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This article references 494 other publications.

Harborne, J. B. ; Williams, C. A. Advances in Flavonoid Research since 1992. Phytochemistry 2000, 55 , 481– 504, DOI: 10.1016/S0031-9422(00)00235-1

[Crossref], [PubMed], [CAS], Google Scholar

Advances in flavonoid research since 1992

Harborne, J. B.; Williams, C. A.

Phytochemistry (2000), 55 (6), 481-504CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science Ltd.)

A review with over 200 refs. Some of the recent advances in flavonoid research are reviewed. The role of anthocyanins and flavones in providing stable blue flower colors in the angiosperms is outlined. The contribution of leaf flavonoids to UV-B protection in plants is critically discussed. Advances in understanding the part played by flavonoids in warding off microbial infection and protecting plants from herbivory are described. The biol. properties of flavonoids are considered in an evaluation of the medicinal and nutritional values of these compds.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXosFent74%253D&md5=6af3a4661f27d5d3052f28781b235da9

Hoballah, M. E. ; Gübitz, T. ; Stuurman, J. ; Broger, L. ; Barone, M. ; Mandel, T. ; Dell'Olivo, A. ; Arnold, M. ; Kuhlemeier, C. Single Gene-Mediated Shift in Pollinator Attraction in Petunia. Plant Cell 2007, 19 , 779– 790, DOI: 10.1105/tpc.106.048694

[Crossref], [PubMed], [CAS], Google Scholar

Single gene-mediated shift in pollinator attraction in Petunia

Hoballah, Maria Elena; Gubitz, Thomas; Stuurman, Jeroen; Broger, Larissa; Barone, Mario; Mandel, Therese; Dell'Olivo, Alexandre; Arnold, Maeva; Kuhlemeier, Cris

Plant Cell (2007), 19 (3), 779-790CODEN: PLCEEW; ISSN:1040-4651. (American Society of Plant Biologists)

Animal-mediated pollination is essential in plant reproductive biol. and is often assocd. with pollination syndromes, sets of floral traits, such as color, scent, shape, or nectar content. Selection by pollinators is often considered a key factor in floral evolution and plant speciation. The aim of this study was the identification and characterization of the genetic changes that caused the evolution of divergent pollination syndromes in closely related plant species. The authors focused on ANTHOCYANIN2 (AN2), a well-defined myb-type transcription factor that is a major determinant of flower color variation between Petunia integrifolia and Petunia axillaris. Anal. of sequence variation in AN2 in wild P. axillaris accessions showed that loss-of-function alleles arose at least five times independently. DNA sequence anal. was complemented by functional assays for pollinator preference using genetic introgressions and transgenics. These results show that AN2 is a major determinant of pollinator attraction. Therefore, changes in a single gene cause a major shift in pollination biol. and support the notion that the adaptation of a flowering plant to a new pollinator type may involve a limited no. of genes of large effect. Gene identification and anal. of mol. evolution in combination with behavioral and ecol. studies can ultimately unravel the evolutionary genetics of pollination syndromes.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXltFyqtbY%253D&md5=468c7a841f5c9928650dd74cf3b8280b

Ahmed, N. U. ; Park, J. I. ; Jung, H. J. ; Yang, T. J. ; Hur, Y. ; Nou, I. S. Characterization of Dihydroflavonol 4-Reductase (Dfr) Genes and Their Association with Cold and Freezing Stress in Brassica Rapa. Gene 2014, 550 , 46– 55, DOI: 10.1016/j.gene.2014.08.013

[Crossref], [PubMed], [CAS], Google Scholar

Characterization of dihydroflavonol 4-reductase (DFR) genes and their association with cold and freezing stress in Brassica rapa

Ahmed, Nasar Uddin; Park, Jong-In; Jung, Hee-Jeong; Yang, Tae-Jin; Hur, Yoonkang; Nou, Ill-Sup

Gene (2014), 550 (1), 46-55CODEN: GENED6; ISSN:0378-1119. (Elsevier B.V.)

Flavonoids including anthocyanins provide flower and leaf colors, as well as other derivs. that play diverse roles in plant development and interactions with the environment. Dihydroflavonol 4-reductase (DFR) is part of an important step in the flavonoid biosynthetic pathway of anthocyanins. This study characterized 12 DFR genes of Brassica rapa and investigated their assocn. with anthocyanin coloration, as well as cold and freezing stress in several genotypes of B. rapa. Comparison of sequences of these genes with DFR gene sequences from other species revealed a high degree of homol. Constitutive expression of the genes in several pigmented and non-pigmented lines of B. rapa demonstrated correlation with anthocyanin accumulation for BrDFR8 and 9. Conversely, BrDFR2, 4, 8 and 9 only showed very high responses to cold stress in pigmented B. rapa samples. BrDFR1, 3, 5, 6 and 10 responded to cold and freezing stress treatments, regardless of pigmentation. BrDFRs were also shown to be regulated by two transcription factors, BrMYB2-2 and BrTT8, contrasting with anthocyanin accumulation and cold and freezing stress. Thus, the above results suggest that these genes are assocd. with anthocyanin biosynthesis and cold and freezing stress tolerance and might be useful resources for development of cold and/or freezing stress resistant Brassica crops with desirable colors as well. These findings may also facilitate exploration of the mol. mechanism that regulates anthocyanin biosynthesis and its response to abiotic stresses.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtlWqsrrO&md5=e38348f82068bb981b59fa3f780a6605

Chalker-Scott, L. Environmental Significance of Anthocyanins in Plant Stress Responses. Photochem. Photobiol. 1999, 70 , 1– 9, DOI: 10.1111/j.1751-1097.1999.tb01944.x

[Crossref], [CAS], Google Scholar

Environmental significance of anthocyanins in plant stress responses

Chalker-Scott, Linda

Photochemistry and Photobiology (1999), 70 (1), 1-9CODEN: PHCBAP; ISSN:0031-8655. (American Society for Photobiology)

A review with 139 refs. concerning the environmental induction of anthocyanins and their proposed importance in ameliorating environmental stresses induced by visible and UVB radiation, drought and cold temps. Anthocyanins are water-sol. pigments found in all plant tissues throughout the plant kingdom. The understanding of anthocyanin biosynthesis and its mol. control has greatly improved in the last decade. The adaptive advantages of anthocyanins, esp. in non-reproductive tissues, is much less clear. Anthocyanins often appear transiently at specific developmental stages and may be induced by a no. of environmental factors including visible and UV-B radiation, cold temps. and water stress. The subsequent prodn. and localization of anthocyanins in root, stem and esp. leaf tissues may allow the plant to develop resistance to a no. of environmental stresses.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksFOktr0%253D&md5=1f8099b5e134b9df6cc2dc9b144aacfa

Guo, J. ; Wang, M. Ultraviolet a-Specific Induction of Anthocyanin Biosynthesis and Pal Expression in Tomato (Solanum Lycopersicum L.). Plant Growth Regul. 2010, 62 , 1– 8, DOI: 10.1007/s10725-010-9472-y

[Crossref], [CAS], Google Scholar

Ultraviolet A-specific induction of anthocyanin biosynthesis and PAL expression in tomato (Solanum lycopersicum L.)

Guo, Jia; Wang, Myeong-Hyeon

Plant Growth Regulation (2010), 62 (1), 1-8CODEN: PGRED3; ISSN:0167-6903. (Springer)

UV A (UV-A) is an environmental stimulus, and UV-A-induced anthocyanin biosynthesis has been previously investigated in the tomato plant (Solanum lycopersicum L.). UV-A induced anthocyanin biosynthesis in tomato seedlings and co-irradn. with visible light and UV-A did not influence the content of UV-A-induced anthocyanin accumulation. UV-A irradn. induced significant accumulations of anthocyanin in both the cotyledons and hypocotyls of tomato seedlings. Anthocyanin prodn. increased gradually in the tomato hypocotyls after exposure to UV-A and reached max. levels at 12 h. In the cotyledons, anthocyanin accumulation was significantly increased at 1 h after UV-A exposure and was reduced afterward; however, it increased again beginning at 3 h. The expression of the phenylalanine ammonia-lyase (SlPAL5) gene was shown to be increased after UV-A exposure in a time-dependent manner. UV-A irradn. was also shown to induce anthocyanin accumulation in the epidermis of the tomato fruit; however, SlPAL5 transcripts were detected only at 3 and 24 h after UV-A treatment. After a 1 h pulse of UV-A, SlPAL5 transcripts were increased significantly in tomato cotyledons and hypocotyls after transfer to dark conditions for a short time.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptlGju70%253D&md5=d07f58b8a212123ebdbd950b88cb33eb

Zhu, H. ; Zhang, T. J. ; Zheng, J. ; Huang, X. D. ; Yu, Z. C. ; Peng, C. L. ; Chow, W. S. Anthocyanins Function as a Light Attenuator to Compensate for Insufficient Photoprotection Mediated by Nonphotochemical Quenching in Young Leaves of Acmena Acuminatissima in Winter. Photosynthetica 2018, 56 , 445– 454, DOI: 10.1007/s11099-017-0740-1

[Crossref], [CAS], Google Scholar

Anthocyanins function as a light attenuator to compensate for insufficient photoprotection mediated by nonphotochemical quenching in young leaves of Acmena acuminatissima in winter

Zhu, H.; Zhang, T.-J.; Zheng, J.; Huang, X.-D.; Yu, Z.-C.; Peng, C.-L.; Chow, W. S.

Photosynthetica (2018), 56 (1), 445-454CODEN: PHSYB5; ISSN:0300-3604. (Springer)

Anthocyanins and nonphotochem. quenching (NPQ) are two important tools that provide photoprotection in plant leaves. In order to understand how plants use these tools for acclimation to changing seasonal conditions, we investigated pigments, antioxidative capacity, and photosynthesis in leaves of an evergreen tree (Acmena acuminatissima) in two contrasting seasons. Young leaves of A. acuminatissima appeared in distinct colors, being light green in summer and red in winter due to the presence of anthocyanins. In the winter young leaves, anthocyanins contributed less than 2% to the antioxidant pool. In the summer, young leaves had higher NPQ than that of mature leaves, but in the winter, they did not derive any NPQ-related advantage over mature leaves. These results suggest that the accumulation of anthocyanins in young leaves in the winter may compensate for the insufficient photoprotection afforded by NPQ and that anthocyanins function as a light attenuator to protect the photochem. app. against excess light.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVOjsrnO&md5=55e1aa60f9aa53e7cad666839a8bb9f6

Tilbrook, J. ; Tyerman, S. D. Cell Death in Grape Berries: Varietal Differences Linked to Xylem Pressure and Berry Weight Loss. Funct. Plant Biol. 2008, 35 , 173– 184, DOI: 10.1071/FP07278

[Crossref], [PubMed], [CAS], Google Scholar

Cell death in grape berries: varietal differences linked to xylem pressure and berry weight loss

Tilbrook Joanne; Tyerman Stephen D

Functional plant biology : FPB (2008), 35 (3), 173-184 ISSN:.

Some varieties of Vitis vinifera L. can undergo berry weight loss during later stages of ripening. This defines a third phase of development in addition to berry formation and berry expansion. Berry weight loss is due to net water loss, but the component water flows through different pathways have remained obscure. Because of the very negative osmotic potential of the cell sap, the maintenance of semipermeable membranes in the berry is required for the berry to counter xylem and apoplast tensions that may be transferred from the vine. The transfer of tension is determined by the hydraulic connection through the xylem from the berry to the vine, which changes during development. Here we assess the membrane integrity of three varieties of V. vinifera berries (cvv. Shiraz, Chardonnay and Thompson seedless) throughout development using the vitality stains, fluorescein diacetate and propidium iodide, on fresh longitudinal sections of whole berries. We also measured the xylem pressure using a pressure probe connected to the pedicel of detached berries. The wine grapes, Chardonnay and Shiraz, maintained fully vital cells after veraison and during berry expansion, but began to show cell death in the mesocarp and endocarp at or near the time that the berries attain maximum weight. This corresponded to a change in rate of accumulation of solutes in the berry and the beginning of weight loss in Shiraz, but not in Chardonnay. Continuous decline in mesocarp and endocarp cell vitality occurred for both varieties until normal harvest dates. Shiraz grapes classified as high quality and sourced from a different vineyard also showed the same death response at the same time after anthesis, but they displayed a more consistent pattern of pericarp cell death. The table grape, Thompson seedless, showed near to 100% vitality for all cells throughout development and well past normal harvest date, except for berries with noticeable berry collapse that were treated with giberellic acid. The high cell vitality in Thompson seedless berries corresponded to negative xylem pressures that contrasted to the slightly positive pressures for Shiraz and Chardonnay. We hypothesise that two variety dependent strategies exist for grapevine berries late in development: (1) programmed cell death in the pericarp and loss of osmotically competent membranes that requires concomitant reduction in the hydraulic conductance via the xylem to the vine; (2) continued cell vitality and osmotically competent membranes that can allow high hydraulic conductance to the vine.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB38jkvVGktQ%253D%253D&md5=760f2829cccdf1239cab9275518ca6db

Xiao, Z. ; Liao, S. ; Rogiers, S. Y. ; Sadras, V. O. ; Tyerman, S. D. Effect of Water Stress and Elevated Temperature on Hypoxia and Cell Death in the Mesocarp of Shiraz Berries. Aust. J. Grape Wine Res. 2018, 24 , 487– 497, DOI: 10.1111/ajgw.12363

[Crossref], [CAS], Google Scholar

Effect of water stress and elevated temperature on hypoxia and cell death in the mesocarp of Shiraz berries

Xiao, Z.; Liao, S.; Rogiers, S. Y.; Sadras, V. O.; Tyerman, S. D.

Australian Journal of Grape and Wine Research (2018), 24 (4), 487-497CODEN: AJGRFF; ISSN:1322-7130. (Wiley-Blackwell)

Berry shrivel during ripening is cultivar dependent and is correlated with berry cell death (CD). We hypothesised that under heat stress and water stress, regions of the pericarp in Shiraz berries would become hypoxic depending on berry porosity, and that this would induce CD. We measured CD and [O2] across the pericarp in berries developed under the factorial combination of two thermal regimes (ambient and heated) and two irrigation regimes (irrigated and non-irrigated) in the Barossa Valley, South Australia. Heating increased ambient temp. by 0.6°C for irrigated and 1°C for non-irrigated vines but had no effect on water relations, while non-irrigation decreased stomatal conductance and stem water potential. Non-irrigation decreased berry [O2] and increased both CD and ethanol concn. relative to irrigation. An assocn. was established between mesocarp [O2] and CD. Berry respiration and total berry porosity decreased during berry ripening, but relative locule air-space measured by X-ray micro-computed tomog. increased late in ripening. Heating had little or no effect on CD or [O2] but decreased berry porosity, which was not affected by irrigation. Water stress increased berry CD, which was assocd. with increased hypoxia. The assocn. between berry [O2] and CD provides insights into berry ripening with implications for yield and berry flavor.

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Fernandes, I. ; Pérez-Gregorio, R. ; Soares, S. ; Mateus, N. ; De Freitas, V. Wine Flavonoids in Health and Disease Prevention. Molecules 2017, 22 , 292, DOI: 10.3390/molecules22020292

[Crossref], [CAS], Google Scholar

Wine flavonoids in health and disease prevention

Fernandes, Iva; Perez-Gregorio, Rosa; Soares, Susana; Mateus, Nuno; de Freitas, Victor

Molecules (2017), 22 (2), 292/1-292/28CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

Wine, and particularly red wine, is a beverage with a great chem. complexity that is in continuous evolution. Chem., wine is a hydroalcoholic soln. (∼78% water) that comprises a wide variety of chem. components, including aldehydes, esters, ketones, lipids, minerals, org. acids, phenolics, sol. proteins, sugars and vitamins. Flavonoids constitute a major group of polyphenolic compds. which are directly assocd. with the organoleptic and health-promoting properties of red wine. However, due to the insufficient epidemiol. and in vivo evidences on this subject, the presence of a high no. of variables such as human age, metab., the presence of alc., the complex wine chem., and the wide array of in vivo biol. effects of these compds. suggest that only cautious conclusions may be drawn from studies focusing on the direct effect of wine and any specific health issue. Nevertheless, there are several reports on the health protective properties of wine phenolics for several diseases such as cardiovascular diseases, some cancers, obesity, neurodegenerative diseases, diabetes, allergies and osteoporosis. The different interactions that wine flavonoids may have with key biol. targets are crucial for some of these health-promoting effects. The interaction between some wine flavonoids and some specific enzymes are one example. The way wine flavonoids may be absorbed and metabolized could interfere with their bioavailability and therefore in their health-promoting effect. Hence, some reports have focused on flavonoids absorption, metab., microbiota effect and overall on flavonoids bioavailability. This review summarizes some of these major issues which are directly related to the potential health-promoting effects of wine flavonoids. Reports related to flavonoids and health highlight some relevant scientific information. However, there is still a gap between the knowledge of wine flavonoids bioavailability and their health-promoting effects. More in vivo results as well as studies focused on flavonoid metabolites are still required. Moreover, it is also necessary to better understand how biol. interactions (with microbiota and cells, enzymes or general biol. systems) could interfere with flavonoid bioavailability.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXps1Witbs%253D&md5=124bafc12beae0fcfd643a6558eea98a

Quideau, S. ; Deffieux, D. ; Douat-Casassus, C. ; Pouységu, L. Plant Polyphenols: Chemical Properties, Biological Activities, and Synthesis. Angew. Chem., Int. Ed. 2011, 50 , 586– 621, DOI: 10.1002/anie.201000044

[Crossref], [CAS], Google Scholar

Plant polyphenols: Chemical properties, biological activities, and synthesis

Quideau, Stephane; Deffieux, Denis; Douat-Casassus, Celine; Pouysegu, Laurent

Angewandte Chemie, International Edition (2011), 50 (3), 586-621CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

A review. Eating five servings of fruits and vegetables per day!!This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why The answer is in fact still under scientific scrutiny, but a particular class of compds. naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really What are their physicochem. properties How do they express their biol. activity Are they really valuable for disease prevention Can they be used to develop new pharmaceutical drugs What recent progress has been made toward their prepn. by org. synthesis This Review gives answers from a chem. perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmtFGjsw%253D%253D&md5=e1469df2ccba3b121680dff0b43b696a

Bars-Cortina, D. ; Sakhawat, A. ; Piñol-Felis, C. ; Motilva, M.-J. Chemopreventive Effects of Anthocyanins on Colorectal and Breast Cancer: A Review. Semin. Cancer Biol. 2021, DOI: 10.1016/j.semcancer.2020.12.013

Ma, Y. ; Ding, S. ; Fei, Y. ; Liu, G. ; Jang, H. ; Fang, J. Antimicrobial Activity of Anthocyanins and Catechins against Foodborne Pathogens Escherichia Coli and Salmonella. Food Control 2019, 106 , 106712, DOI: 10.1016/j.foodcont.2019.106712

[Crossref], [CAS], Google Scholar

Antimicrobial activity of anthocyanins and catechins against foodborne pathogens Escherichia coli and Salmonella

Ma, Yong; Ding, Sujuan; Fei, Yanquan; Liu, Gang; Jang, Hongmei; Fang, Jun

Food Control (2019), 106 (), 106712CODEN: FOOCEV; ISSN:0956-7135. (Elsevier Ltd.)

A review. The main foodborne pathogens are Norovirus, Enteric parasites, bacteria and fungi. Foodborne diseases can lead to high morbidity and mortality and result in huge economic losses. Some foodborne diseases are assocd. with antibiotic resistance, which is a significant problem throughout the world. To reduce the harm caused by antibiotics, it is important to find alternatives so that food is not infected with foodborne pathogens. Anthocyanins and catechins, two species of plant polyphenols with strong antioxidant properties, offer a promising new approach to preventing foodborne disease. Recent studies have shown that these compds. are good growth inhibitors. In this review, we focus on the antibacterial properties of anthocyanins and catechins as antibiotic substitutes. The min. inhibitory concn. (MIC) of anthocyanins against E. coli and Salmonella is 10-400 mg/mL. The MIC of catechins against E. coli and Salmonella is 6-50 mg/mL. Anthocyanins and catechins can also significantly reduce the abundance of pathogenic bacteria that produce toxins in the host including Desulfovibrio sp. and Enterococcus. At the same time, we summarize the antibacterial mechanism of Anthocyanins and catechins on Salmonella and Escherichia coli. Anthocyanins and catechins can increase the abundance of probiotics such as Akkermansia, Bifidobacteria, and increase the ratio of thick-walled bacteria to Bacteroides. Finally, it seems that Anthocyanins and catechins can regulate the compn. of intestinal microbes to improve intestinal immunity and promote intestinal health, thereby controlling foodborne.

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Oliveira, H. ; Fernandes, I. ; de Freitas, V. ; Mateus, N. Ageing Impact on the Antioxidant and Antiproliferative Properties of Port Wines. Food Res. Int. 2015, 67 , 199– 205, DOI: 10.1016/j.foodres.2014.10.034

[Crossref], [CAS], Google Scholar

Ageing impact on the antioxidant and antiproliferative properties of Port wines

Oliveira, Helder; Fernandes, Iva; de Freitas, Victor; Mateus, Nuno

Food Research International (2015), 67 (), 199-205CODEN: FORIEU; ISSN:0963-9969. (Elsevier B.V.)

This study is focused on the impact of Port wine ageing on some antioxidant features and antiproliferative properties towards human cancer cells. For this, two types of Port wines with different ageing stages were used: a young Vintage and a 20-yr-old Tawny. The wines were dealcoholized and two wine phenolic fractions were also characterized and tested. The radical scavenging capacity was similar amongst the wines tested but the reducing capacity was significantly reduced for both Port wine exts. The results from the FRAP assay, but not DPPH, seem to be pos. correlated with the amts. of phenolics with lower structural complexity. MKN-28 (stomach) was found to be the most susceptible cell line to the antiproliferative effect of the young Vintage Port. However, for all wines, Caco-2 (colon) was the cell line that showed the lowest IC50. Interestingly, the old Tawny Port was found to maintain some antiproliferative activity.

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Oliveira, H. ; Correia, P. ; Pereira, A. R. ; Araújo, P. ; Mateus, N. ; de Freitas, V. ; Oliveira, J. ; Fernandes, I. Exploring the Applications of the Photoprotective Properties of Anthocyanins in Biological Systems. Int. J. Mol. Sci. 2020, 21 , 7464, DOI: 10.3390/ijms21207464

[Crossref], [CAS], Google Scholar

Exploring the applications of the photoprotective properties of anthocyanins in biological systems

Oliveira, Helder; Correia, Patricia; Pereira, Ana Rita; Araujo, Paula; Mateus, Nuno; De Freitas, Victor; Oliveira, Joana; Fernandes, Iva

International Journal of Molecular Sciences (2020), 21 (20), 7464CODEN: IJMCFK; ISSN:1422-0067. (MDPI AG)

A review. Due to their phys. and chem. characteristics, anthocyanins are amongst the most versatile groups of natural compds. Such unique signature makes these compds. a focus in several different areas of research. Anthocyanins have well been reported as bioactive compds. in a myriad of health disorders such as cardiovascular diseases, cancer, and obesity, among others, due to their anti-inflammatory, antioxidant, anti-diabetic, anti-bacterial, and anti-proliferative capacities. Such a vast no. of action mechanisms may be also due to the no. of structurally different anthocyanins plus their related derivs. In this review, we highlight the recent advances on the potential use of anthocyanins in biol. systems with particular focus on their photoprotective properties. Topics such as skin aging and eye degenerative diseases, highly influenced by light, and the action of anthocyanins against such damages will be discussed. Photodynamic Therapy and the potential role of anthocyanins as novel photosensitizers will be also a central theme of this review.

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Amogne, N. Y. ; Ayele, D. W. ; Tsigie, Y. A. Recent Advances in Anthocyanin Dyes Extracted from Plants for Dye Sensitized Solar Cell. Mater. Renew. Sustain. Energy 2020, 9 , 23, DOI: 10.1007/s40243-020-00183-5

Roy, S. ; Rhim, J.-W. Anthocyanin Food Colorant and Its Application in Ph-Responsive Color Change Indicator Films. Crit. Rev. Food Sci. Nutr. 2021, 61 , 2297– 2235, DOI: 10.1080/10408398.2020.1776211

[Crossref], [PubMed], [CAS], Google Scholar

Anthocyanin food colorant and its application in pH-responsive color change indicator films

Roy, Swarup; Rhim, Jong-Whan

Critical Reviews in Food Science and Nutrition (2021), 61 (14), 2297-2325CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)

A review. Recently, interest in smart packaging, which can show the color change of the packaging film according to the state of the food and evaluate the quality or freshness of the packaged food in real-time, is increasing. As a color indicator, a natural colorant, anthocyanin, drew a lot of attention due to their various colors as well as useful functions properties such as antioxidant activity and anti-carcinogenic and anti-inflammatory effects, prevention of cardiovascular disease, obesity, and diabetes. In particular, the pH-responsive color-changing function of anthocyanins is useful for making color indicator smart packaging films. This review addressed the latest information on the use of natural pigment anthocyanins for intelligent and active food packaging applications. Recent studies on eco-friendly biodegradable polymer-based color indicator films incorporated with anthocyanins have been addressed. Also, studies on the use of smart packaging films to monitor the freshness of foods such as milk, meat, and fish were reviewed. This review highlights the potential and challenges for the use of anthocyanins as pH-responsive color-changing films for intelligent food packaging applications, which may be beneficial for further development of smart color indicator films for practical use.

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Willstätter, R. ; Everest, A. E. Untersuchungen Über Die Anthocyane. I. Über Den Farbstoff Der Kornblume. Justus Liebigs Ann. Chem. 1913, 401 , 189– 232, DOI: 10.1002/jlac.19134010205

Robinson, R. ; Todd, A. R. Experiments on the Synthesis of Anthocyanins Part Xvii the Syntheses of Pelargonin, Peonin, and Cyanin Chlorides. J. Chem. Soc. 1932, 2488– 2496, DOI: 10.1039/jr9320002488

[Crossref], [CAS], Google Scholar

Anthocyanins. XVII. The syntheses of pelargonin, peonin and cyanin chlorides

Robinson, Robert; Todd, A. R.

Journal of the Chemical Society (1932), (), 2488-96CODEN: JCSOA9; ISSN:0368-1769.

2-O-Monoacetyl-β-glucosidylphloroglucinaldehyde and ω-O-tetraacetyl-β-glucosidoxy-4-acetoxyacetophenone, satd. with HCl in AcOEt, give 7-hydroxy-3-O-tetraacetyl-β-glucosidoxy-5-O-monoacetyl-β-glucosidoxy-4'-acetoxyflavylium chloride, scarle-red powder, contg. 2 mols. H2O; NaOH, followed by HCl, gives pelargonin chloride, identical with the natural product. 2-O-Tetraacetyl-β-glucosidylphloroglucinaldehyde (I) and ω-O-tetraacetyl-β-glucosidoxy-4-acetoxy-3-methoxyacetophenone, m. 103°, for which an improved method of prepn. is given, give with HCl in AcOEt 7-hydroxy-3, -di(O-tetraacetyl-β-glucosidoxyl)-4'-acetoxy-3-methoxyflavylium chloride, carmine-red, crystg. with 2 mols. H2O; NaOH and HCl give peonin chloride, which comparison shows to be identical with the natural product. I and ω-O-tetraacetyl-β-glucosidoxy-3,4-diacetoxyacetophenone give 7-hydroxy-3, 5-di(O-tetraacetyl-β-glucosidoxy)-3',4'-diacetoxyflavylium chloride, scarlet-red, crystg. with 2 mols. H2O; this yields on hydrolysis and warming with HCl, cyanin chloride, identical with the natural product.

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Andersen, O. M.; Markham, K. R. The Anthocyanins. Flavonoids: Chemistry, Biochemistry, and Applications; CRC Press: Boca Raton, FL, 2006; Chapter 10, pp 471– 551.

Wallace, T. C. ; Giusti, M. M. Anthocyanins─Nature's Bold, Beautiful, and Health-Promoting Colors. Foods 2019, 8 , 550, DOI: 10.3390/foods8110550

[Crossref], [CAS], Google Scholar

Anthocyanins-nature's bold, beautiful, and health-promoting colors

Wallace, Taylor C.; Giusti, M. Monica

Foods (2019), 8 (11), 550CODEN: FOODBV; ISSN:2304-8158. (MDPI AG)

Anthocyanins are among the most interesting and vigorously studied plant compds., representing a large class of over 700 polyphenolic pigments within the flavonoid family that exist ubiquitously in the human diet. They are "nature's colors," responsible for providing the beautiful red-orange to blue-violet hues present in many leaves, flowers, vegetables, and fruits, esp. berries. The beginning of the 21st century has witnessed a renaissance in research activities on anthocyanins in several areas, mainly related to their potential health-promoting properties and their increased use as alternatives to synthetic food colors. There is increasingly convincing scientific evidence that supports both a preventative and therapeutic role of anthocyanins towards certain chronic disease states. Many anthocyanin-based exts. and juice concs. from crop and/or food processing waste have become com. available as colorants and/or value-added food ingredients. There is a large and evolving peer-reviewed literature on how anthocyanin chem. and concn. may affect their coloring properties in food. Equally as important is the food matrix, which can have large impacts on anthocyanin color expression, stability and degrdn., particularly regarding the applications of anthocyanins as food colorants and their health-promoting properties. This Special Edition of Foods, titled "Anthocyanins in Foods," presents original research that extends our understanding of these exciting and complex compds.

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Oliveira, J. ; Alhinho da Silva, M. ; Teixeira, N. ; De Freitas, V. ; Salas, E. Screening of Anthocyanins and Anthocyanin-Derived Pigments in Red Wine Grape Pomace Using Lc-Dad/Ms and Maldi-Tof Techniques. J. Agric. Food Chem. 2015, 63 , 7636– 7644, DOI: 10.1021/acs.jafc.5b00256

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Screening of Anthocyanins and Anthocyanin-Derived Pigments in Red Wine Grape Pomace Using LC-DAD/MS and MALDI-TOF Techniques

Oliveira, Joana; Alhinho da Silva, Mara; Teixeira, Natercia; De Freitas, Victor; Salas, Erika

Journal of Agricultural and Food Chemistry (2015), 63 (35), 7636-7644CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Two phenolic exts. were made from a red wine grape pomace (GP) and fractionated first by sequential liq.-liq. extn. with org. solvents. The aq. fraction was fractionated by low-pressure chromatog. on Toyopearl HW-40 gel and on C18. Different fractions were obtained by sequential elution with aq./org. solvents, and then analyzed by liq. chromatog. and mass spectrometry (LC-DAD/MS and MALDI-TOF). Over 50 anthocyanin-based pigments were detected by LC-DAD/MS in GP, mainly pyranoanthocyanins including A- and B-type vitisins and methylpyranoanthocyanins. The presence of oligomeric malvidin-3-O-coumaroylglucoside-based anthocyanins was also detected in GP using both LC-DAD/MS and MALDI-TOF.

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Clifford, M. N. Anthocyanins - Nature, Occurrence and Dietary Burden. J. Sci. Food Agric. 2000, 80 , 1063– 1072, DOI: 10.1002/(SICI)1097-0010(20000515)80:7<1063::AID-JSFA605>3.0.CO;2-Q

[Crossref], [CAS], Google Scholar

Anthocyanins - nature, occurrence and dietary burden

Clifford, Michael N.

Journal of the Science of Food and Agriculture (2000), 80 (7), 1063-1072CODEN: JSFAAE; ISSN:0022-5142. (John Wiley & Sons Ltd.)

A review with 103 refs. discussing the occurrence of anthocyanins in foods and their transformation during processing, including the formation of adducts and derived tannins. Data describing the safety of anthocyanins and possible dietary effects are examd. Attention is drawn to some misquotations in the literature and to some serious gaps in our knowledge, in particular, the lack of pharmacokinetic data in humans essential to an understanding of assocd. biol. effects.

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Berland, H. ; Albert, N. W. ; Stavland, A. ; Jordheim, M. ; McGhie, T. K. ; Zhou, Y. ; Zhang, H. ; Deroles, S. C. ; Schwinn, K. E. ; Jordan, B. R. Auronidins Are a Previously Unreported Class of Flavonoid Pigments That Challenges When Anthocyanin Biosynthesis Evolved in Plants. Proc. Natl. Acad. Sci. U. S. A. 2019, 116 , 20232– 20239, DOI: 10.1073/pnas.1912741116

[Crossref], [PubMed], [CAS], Google Scholar

Auronidins are a previously unreported class of flavonoid pigments that challenges when anthocyanin biosynthesis evolved in plants

Berland, Helge; Albert, Nick W.; Stavland, Anne; Jordheim, Monica; McGhie, Tony K.; Zhou, Yanfei; Zhang, Huaibi; Deroles, Simon C.; Schwinn, Kathy E.; Jordan, Brian R.; Davies, Kevin M.; Andersen, Ayvind M.

Proceedings of the National Academy of Sciences of the United States of America (2019), 116 (40), 20232-20239CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)

Anthocyanins are key pigments of plants, providing color to flowers, fruit, and foliage and helping to counter the harmful effects of environmental stresses. It is generally assumed that anthocyanin biosynthesis arose during the evolutionary transition of plants from aquatic to land environments. Liverworts, which may be the closest living relatives to the first land plants, have been reported to produce red cell wall-bound riccionidin pigments in response to stresses such as UV-B light, drought, and nutrient deprivation, and these have been proposed to correspond to the first anthocyanidins present in early land plant ancestors. Taking advantage of the liverwort model species Marchantia polymorpha, we show that the red pigments of Marchantia are formed by a phenylpropanoid biosynthetic branch distinct from that leading to anthocyanins. They constitute a previously unreported flavonoid class, for which we propose the name auronidin, with similar colors as anthocyanin but different chem., including strong fluorescence. Auronidins might contribute to the remarkable ability of liverworts to survive in extreme environments on land, and their discovery calls into question the possible pigment status of the first land plants.

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Khalil, A. ; Baltenweck-Guyot, R. ; Ocampo-Torres, R. ; Albrecht, P. A Novel Symmetrical Pyrano-3-Deoxyanthocyanidin from a Sorghum Species. Phytochem. Lett. 2010, 3 , 93– 95, DOI: 10.1016/j.phytol.2010.02.003

[Crossref], [CAS], Google Scholar

A novel symmetrical pyrano-3-deoxyanthocyanidin from a Sorghum species

Khalil, Ali; Baltenweck-Guyot, Raymonde; Ocampo-Torres, Ruben; Albrecht, Pierre

Phytochemistry Letters (2010), 3 (2), 93-95CODEN: PLHEBK; ISSN:1874-3900. (Elsevier B.V.)

Polyphenols are widespread components of higher plants. Sorghum is rich in polyphenols and known to contain a specific type, 3-deoxyanthocyanins, many of which remain uncharacterized. Here we report the structural detn. of a new pigment isolated from red Sorghum bicolor var. bicolor (Moench) and characterized as 8-hydroxy-2-(4'-hydroxyphenyl)-5-(4"-hydroxyphenyl)-pyrano[4,3,2-de]1-benzopyrylium by MS, UV-vis and 2D NMR spectroscopy. This new sym. pyrano-3-deoxyanthocyanidin, contg. apigeninidin as a base unit, displays structural features responsible for higher stability as compared to corresponding anthocyanins.

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Berké, B. ; Chèze, C. ; Vercauteren, J. ; Deffieux, G. Bisulfite Addition to Anthocyanins: Revisited Structures of Colorless Adducts. Tetrahedron Lett. 1998, 39 , 5771– 5774, DOI: 10.1016/S0040-4039(98)01205-2

[Crossref], [CAS], Google Scholar

Bisulfite addition to anthocyanins: revisited structures of colorless adducts

Berke, Benedicte; Cheze, Catherine; Vercauteren, Joseph; Deffieux, Gerard

Tetrahedron Letters (1998), 39 (32), 5771-5774CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

Decolorization of anthocyanins by sulfur dioxide is investigated through the reaction between sodium bisulfite and malvidin 3-O-glucoside. The structural elucidation of the C-4 sulfonate adducts is established by 1H, 13C and 33S NMR spectroscopies.

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Berké, B. ; De Freitas, V. A. P. Influence of Procyanidin Structures on Their Ability to Complex with Oenin. Food Chem. 2005, 90 , 453– 460, DOI: 10.1016/j.foodchem.2004.05.009

Fernandes, A. ; Bras, N. F. ; Oliveira, J. ; Mateus, N. ; de Freitas, V. Impact of a Pectic Polysaccharide on Oenin Copigmentation Mechanism. Food Chem. 2016, 209 , 17– 26, DOI: 10.1016/j.foodchem.2016.04.018

[Crossref], [PubMed], [CAS], Google Scholar

Impact of a pectic polysaccharide on oenin copigmentation mechanism

Fernandes, Ana; Bras, Natercia F.; Oliveira, Joana; Mateus, Nuno; de Freitas, Victor

Food Chemistry (2016), 209 (), 17-26CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Copigmentation plays an important role in the colors provided by anthocyanins. However, little attention has been paid to the interaction between anthocyanins and cell wall compds. (e.g. polysaccharides) and the impact of this interaction on anthocyanins color, a fundamental issue to be considered in industrial applications of these pigments as food colorants. The copigmentation binding consts. (KCP) for the interaction between malvidin-3-O-glucoside and (+)-catechin in the presence of low methoxylated pectic polysaccharide were detd. The values obtained showed that in the presence of pectic polysaccharide the copigmentation binding consts. decreased. These results probably suggest the occurrence of competition equil. in which the presence of pectin limited the assocn. between catechin and oenin. 1H NMR studies revealed that the dissocn. const. detd. for these complexes was very similar in absence and presence of 1.5 g/L pectin with this polysaccharide apparently not affecting the strength of anthocyanin-catechin binding.

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Hondo, T. ; Yoshida, K. ; Nakagawa, A. ; Kawai, T. ; Tamura, H. ; Goto, T. Structural Basis of Blue-Color Development in Flower Petals from Commelina-Communis. Nature 1992, 358 , 515– 518, DOI: 10.1038/358515a0

Yoshida, K. ; Kondo, T. ; Okazaki, Y. ; Katou, K. Cause of Blue Petal Color. Nature 1995, 373 , 291– 291, DOI: 10.1038/373291a0

[Crossref], [CAS], Google Scholar

Cause of blue petal color

Yoshida, Kumi; Kondo, Tadao; Okazaki, Yoshiji; Katou, Kiyoshi

Nature (London) (1995), 373 (6512), 291CODEN: NATUAS; ISSN:0028-0836. (Macmillan Magazines)

A review with 11 refs. of color of Ipomoea tricolor cv. 'Heavenly Blue' flowers and the structure of heavenly blue anthocyanin causing this color.

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Oliveira, J. ; Mateus, N. ; De Freitas, V. Wine-Inspired Chemistry: Anthocyanin Transformations for a Portfolio of Natural Colors. Synlett 2017, 28 , 898– 906, DOI: 10.1055/s-0036-1589937

[Crossref], [CAS], Google Scholar

Wine-Inspired Chemistry: Anthocyanin Transformations for a Portfolio of Natural Colors

Oliveira, Joana; Mateus, Nuno; de Freitas, Victor

Synlett (2017), 28 (8), 898-906CODEN: SYNLES; ISSN:0936-5214. (Georg Thieme Verlag)

A review. During wine aging and maturation, anthocyanins can react with flavanols (directly or mediated by aldehydes) and with small mols. derived from yeast metab. during fermn. It has been demonstrated that A-type vitisins (the main pyranoanthocyanins found in red wines) can react with other wine components yielding pyranoanthocyanin pigments with different colors ranging from yellow to turquoise blue. Wine-color chem. has been an inspiration for the synthesis of new mols. with unique chromatic features.

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Dangles, O. ; Fenger, J.-A. The Chemical Reactivity of Anthocyanins and Its Consequences in Food Science and Nutrition. Molecules 2018, 23 , 1970, DOI: 10.3390/molecules23081970

[Crossref], [PubMed], [CAS], Google Scholar

The chemical reactivity of anthocyanins and its consequences in food science and nutrition

Dangles, Olivier; Fenger, Julie-Anne

Molecules (2018), 23 (8), 1970/1-1970/23CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

A review. Owing to their specific pyrylium nucleus (C-ring), anthocyanins express a much richer chem. reactivity than the other flavonoid classes. For instance, anthocyanins are weak diacids, hard and soft electrophiles, nucleophiles, prone to developing π-stacking interactions, and bind hard metal ions. They also display the usual chem. properties of polyphenols, such as electron donation and affinity for proteins. In this review, these properties are revisited through a variety of examples and discussed in relation to their consequences in food and in nutrition with an emphasis on the transformations occurring upon storage or thermal treatment and on the catabolism of anthocyanins in humans, which is of crit. importance for interpreting their effects on health.

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Rentzsch, M. ; Schwarz, M. ; Winterhalter, P. Pyranoanthocyanins - an Overview on Structures, Occurrence, and Pathways of Formation. Trends Food Sci. Technol. 2007, 18 , 526– 534, DOI: 10.1016/j.tifs.2007.04.014

[Crossref], [CAS], Google Scholar

Pyranoanthocyanins - an overview on structures, occurrence, and pathways of formation

Rentzsch, Michael; Schwarz, Michael; Winterhalter, Peter

Trends in Food Science & Technology (2007), 18 (10), 526-534CODEN: TFTEEH; ISSN:0924-2244. (Elsevier Ltd.)

A review. Since the identification of a new class of anthocyanin-derived pigments in red wine, the so-called pyranoanthocyanins, a lot of scientific information were published dealing with different aspects of these pigments. Depending on their origin as well as different pathways of formation in foodstuff, the pyranoanthocyanins possess varying chem. structures. This report presents an overview of different classes of pyranoanthocyanins, their formation, occurrence, and their relevance for the color and anal. of aged fruit juices and wines.

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Fernandes, A. ; Bras, N. F. ; Mateus, N. ; de Freitas, V. A Study of Anthocyanin Self-Association by Nmr Spectroscopy. New J. Chem. 2015, 39 , 2602– 2611, DOI: 10.1039/C4NJ02339K

[Crossref], [CAS], Google Scholar

A study of anthocyanin self-association by NMR spectroscopy

Fernandes, Ana; Bras, Natercia F.; Mateus, Nuno; Freitas, Victor de

New Journal of Chemistry (2015), 39 (4), 2602-2611CODEN: NJCHE5; ISSN:1144-0546. (Royal Society of Chemistry)

Research involving the development of anthocyanin-contg. food colorants has led to the discovery that acylated anthocyanins exhibit remarkable stability, with this improved stabilization being attributed to intra and inter-mol. assocn. In this work the self-assocn. behavior (intra- and inter-mol. assocn.) of malvidin-3-O-(6-coumaroylglucoside) (mv3cumglc) and malvidin-3-O-glucoside (mv3glc) in the flavylium form (pH 1.0) was studied using a synergistic combination of NMR and mol. dynamics simulation. NOESY expts. have suggested the occurrence of intra-mol. assocn. on malvidin-3-O-coumaroylglucoside with the coumaric acid residue stacking in the anthocyanidin nucleus. The NMR spectral variations (chem. shifts, δ, and diffusion coeffs., D) resulting from the increase of the anthocyanin concn. were analyzed using an isodesmic model. In D2O-DMSO mixts. and in the concn. range tested, mv3cumglc was found to self-assoc. with a higher affinity const. (1402 M-1 (δ) and 2203 M-1 (D)) compared to mv3glc (819 M-1 (δ) and 1002 M-1 (D)) revealing that in acylated anthocyanins the combined aggregation phenomenon could be responsible for this higher affinity towards self-assocn. In D2O-DMSO the crit. aggregation concn. (cac) values detd. for both anthocyanins were very similar, though this value was lower for mv3cumglc.

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Di Meo, F. ; Garcia, J. C. S. ; Dangles, O. ; Trouillas, P. Highlights on Anthocyanin Pigmentation and Copigmentation: A Matter of Flavonoid Pi-Stacking Complexation to Be Described by Dft-D. J. Chem. Theory Comput. 2012, 8 , 2034– 2043, DOI: 10.1021/ct300276p

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Highlights on Anthocyanin Pigmentation and Copigmentation: A Matter of Flavonoid π-Stacking Complexation To Be Described by DFT-D

Di Meo, Florent; Sancho Garcia, Juan Carlos; Dangles, Olivier; Trouillas, Patrick

Journal of Chemical Theory and Computation (2012), 8 (6), 2034-2043CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)

Anthocyanidins are a class of π-conjugated systems responsible for red, blue, and purple colors of plants. They exhibit the capacity of aggregation in the presence of other natural compds. including flavonols. Such complexations induce color modulation in plants, which is known as copigmentation. It is largely driven by π-interactions existing between pigments and copigments. In this work, the energies of copigmentation-complexation and self-assocn. are systematically evaluated for an anthocyanidin/flavonol couple prototype (3-O-methylcyanidin/quercetin). To describe noncovalent interactions, DFT-D appears mandatory to reach a large accuracy. Due to the chem. complexity of this phenomenon, we also aim at assessing the relevance of both B3P86-D2 and ωB97X-D functionals. The benchmarking has shown that B3P86-D2 possesses enough accuracy when dealing with π-π interactions with respect to both spin component scaled Moller-Plesset second-order perturbation theory post Hartree-Fock method and exptl. data. UV-vis absorption properties are then evaluated with time-dependent DFT for the different complexes. The use of range-sepd. hybrid functionals, such as ωB97X-D, helped to correctly disentangle and interpret the origin of the UV-vis exptl. shifts attributed to the subtle copigmentation phenomenon.

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Escribano-Bailon, M. T. ; Santos-Buelga, C. Anthocyanin Copigmentation - Evaluation, Mechanisms and Implications for the Colour of Red Wines. Curr. Org. Chem. 2012, 16 , 715– 723, DOI: 10.2174/138527212799957977

[Crossref], [CAS], Google Scholar

Anthocyanin copigmentation - evaluation, mechanisms and implications for the colour of red wines

Escribano-Bailon, Maite T.; Santos-Buelga, Celestino

Current Organic Chemistry (2012), 16 (6), 715-723CODEN: CORCFE; ISSN:1385-2728. (Bentham Science Publishers Ltd.)

A review. Copigmentation is the main color-stabilizing mechanism in plants and in food products of vegetable origin. It is a spontaneous and exothermic process that consists of the stacking of an org. mol., called copigment, on the planar polarizable moieties of the anthocyanin colored forms. Although this phenomenon has long been described, there are some aspects that are still not well understood or controversial like the nature of the interaction pigment to copigment, the way to quantify the extent of the process, its effect on other anthocyanin properties like astringency or reactivity. In this article a review of the most significant advances achieved in the last years in the field of intramol. and intermol. copigmentation is presented. Also, the most recent findings regarding wine copigments and their effects on the color of red wines are revised.

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He, F. ; Liang, N. N. ; Mu, L. ; Pan, Q. H. ; Wang, J. ; Reeves, M. J. ; Duan, C. Q. Anthocyanins and Their Variation in Red Wines I. Monomeric Anthocyanins and Their Color Expression. Molecules 2012, 17 , 1571– 1601, DOI: 10.3390/molecules17021571

[Crossref], [PubMed], [CAS], Google Scholar

Anthocyanins and their variation in red wines I. Monomeric anthocyanins and their color expression

He, Fei; Liang, Na-Na; Mu, Lin; Pan, Qiu-Hong; Wang, Jun; Reeves, Malcolm J.; Duan, Chang-Qing

Molecules (2012), 17 (), 1571-1601CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

A review. Originating in the grapes, monomeric anthocyanins in young red wines contribute the majority of color and the supposed beneficial health effects related to their consumption, and as such they are recognized as one of the most important groups of phenolic metabolites in red wines. In recent years, our increasing knowledge of the chem. complexity of the monomeric anthocyanins, their stability, together with the phenomena such as self-assocn. and copigmentation that can stabilize and enhance their color has helped to explain their color representation in red wine making and aging. A series of new enol. practices were developed to improve the anthocyanin extn., as well as their color expression and maintenance. This paper summarizes the most recent advances in the studies of the monomeric anthocyanins in red wines, emphasizing their origin, occurrence, color enhancing effects, their degrdn. and the effect of various enol. practices on them.

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Goto, T. ; Kondo, T. Structure and Molecular Stacking of Anthocyanins - Flower Color Variation. Angew. Chem., Int. Ed. Engl. 1991, 30 , 17– 33, DOI: 10.1002/anie.199100171

Mendoza, J. ; Basílio, N. ; Pina, F. ; Kondo, T. ; Yoshida, K. Rationalizing the Color in Heavenly Blue Anthocyanin: A Complete Kinetic and Thermodynamic Study. J. Phys. Chem. B 2018, 122 , 4982– 4992, DOI: 10.1021/acs.jpcb.8b01136

[ACS Full Text ], [CAS], Google Scholar

Rationalizing the Color in Heavenly Blue Anthocyanin: A Complete Kinetic and Thermodynamic Study

Mendoza, Johan; Basilio, Nuno; Pina, Fernando; Kondo, Tadao; Yoshida, Kumi

Journal of Physical Chemistry B (2018), 122 (19), 4982-4992CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

All equil. and rate consts. of heavenly blue anthocyanin (HBA 1) as well as the derivs. with two (HBA 2) or none (HBA 3) acylated units were detd. The three acylated units of the sugar in position 3 of the peonidin chromophore of HBA 1 are essential to confer the peculiar stability of its purple and blue colors. The sugars generate an efficient protective environment around position 2 (and 4) of the flavylium cation, through an intramol. sandwich-type stacking that retards 35-fold the hydration reaction (kh) and increases 8.8-fold the dehydration reaction (k-h), when compared with the peonidin chromophore HBA 3. The conjugation of these two rates lowers 308-fold the hydration equil. const. (Kh), corresponding to a raise of the energy level of the hemiketal by 14.2 kJ mol-1. Conversely, the pKa of the quinoidal base in HBA 1 is only slightly stabilized in comparison with that of HBA 2 and HBA 3. The energy level of hemiketal increases with the no. of acylated units, but the inversion of energies between hemiketal and quinoidal base takes place exclusively for HBA 1 (three acylated units), permitting in moderately acidic solns. the stabilization of the purple quinoidal base. Identical inversion of energy was obsd. for the corresponding ionized species, allowing the stabilization of the blue ionized quinoidal base in slightly basic solns. At pH values higher than 8, the hydroxyl groups of the hydroxycinnamic acid units start to deprotonate disrupting the intramol. sandwich-type stacking and the more or less slow degrdn. of the anthocyanin is obsd.

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Yoshida, K. ; Mori, M. ; Kondo, T. Blue Flower Color Development by Anthocyanins: From Chemical Structure to Cell Physiology. Nat. Prod. Rep. 2009, 26 , 884– 915, DOI: 10.1039/b800165k

[Crossref], [PubMed], [CAS], Google Scholar

Blue flower color development by anthocyanins: from chemical structure to cell physiology

Yoshida, Kumi; Mori, Mihoko; Kondo, Tadao

Natural Product Reports (2009), 26 (7), 884-915CODEN: NPRRDF; ISSN:0265-0568. (Royal Society of Chemistry)

A review. Blue flower colors are primarily due to anthocyanin, a flavonoid pigment. Anthocyanin itself is purple in neutral aq. solns., and its color is very unstable and quickly fades. Therefore, the mechanism of blue color development in living flower petals is one of the most intriguing problems in natural product chem. Much progress has been made in understanding blue flower coloration since the comprehensive review by Goto and Kondo in 1991. This review focuses on the advances in the last 15 years, and cites 149 refs.

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Trouillas, P. ; Sancho-García, J. C. ; De Freitas, V. ; Gierschner, J. ; Otyepka, M. ; Dangles, O. Stabilizing and Modulating Color by Copigmentation: Insights from Theory and Experiment. Chem. Rev. 2016, 116 , 4937– 4982, DOI: 10.1021/acs.chemrev.5b00507

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Stabilizing and Modulating Color by Copigmentation: Insights from Theory and Experiment

Trouillas, Patrick; Sancho-Garcia, Juan C.; De Freitas, Victor; Gierschner, Johannes; Otyepka, Michal; Dangles, Olivier

Chemical Reviews (Washington, DC, United States) (2016), 116 (9), 4937-4982CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. Natural anthocyanin pigments/dyes and phenolic copigments/co-dyes form noncovalent complexes, which stabilize and modulate (in particular blue, violet, and red) colors in flowers, berries, and food products derived from them (including wines, jams, purees, and syrups). This noncovalent assocn. and their electronic and optical implications constitute the copigmentation phenomenon. Over the past decade, exptl. and theor. studies have enabled a mol. understanding of copigmentation. This review revisits this phenomenon to provide a comprehensive description of the nature of binding (the dispersion and electrostatic components of π-π stacking, the hydrophobic effect, and possible hydrogen-bonding between pigment and copigment) and of spectral modifications occurring in copigmentation complexes, in which charge transfer plays an important role. Particular attention is paid to applications of copigmentation in food chem.

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Muller-Maatsch, J. ; Bechtold, L. ; Schweiggert, R. M. ; Carle, R. Co-Pigmentation of Pelargonidin Derivatives in Strawberry and Red Radish Model Solutions by the Addition of Phenolic Fractions from Mango Peels. Food Chem. 2016, 213 , 625– 634, DOI: 10.1016/j.foodchem.2016.06.097

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Co-pigmentation of pelargonidin derivatives in strawberry and red radish model solutions by the addition of phenolic fractions from mango peels

Muller-Maatsch Judith; Bechtold Lena; Schweiggert Ralf M; Carle Reinhold

Food chemistry (2016), 213 (), 625-634 ISSN:.

Pelargonidin-based colors suffer from notorious instability. A phenolic mango peel extract and defined phenolic fractions thereof were shown to effectively modulate the visible absorption of anthocyanins from strawberry (Fragaria x ananassa Duch.) and red radish (Raphanus sativus L.) by intermolecular co-pigmentation. Consistently, non-acylated pelargonidin derivatives from strawberry exerted significantly greater hyper- and bathochromic spectral shifts than their acylated counterparts from red radish. The addition of low molecular-weight co-pigments such as gallic acid and monogalloyl glucoses to strawberry anthocyanins led to strong hyperchromic shifts from 30% to 48%, while gallotannins (>six galloyl units) exerted smaller co-pigmentation effects (36±2%; Δλmax 13nm), possibly due to steric hindrances. In contrast, penta- and hexa-O-galloyl-glucose induced greatest and most stable co-pigmentation effects (53±2%; Δλmax 13nm). Irrespective of the underlying mechanisms and the responsible compounds, phenolic mango peel extracts might represent suitable color enhancers for coloring foodstuff, particularly for those containing non-acylated pelargonidin derivatives.

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Iwashina, T. Contribution to Flower Colors of Flavonoids Including Anthocyanins: A Review. Nat. Prod. Commun. 2015, 10 , 529– 544, DOI: 10.1177/1934578X1501000335

[Crossref], [PubMed], [CAS], Google Scholar

Contribution to flower colors of flavonoids including anthocyanins: a review

Iwashina Tsukasa

Natural product communications (2015), 10 (3), 529-44 ISSN:1934-578X.

Flavonoids are one of the major pigments in higher plants, together with chlorophylls and carotenoids. Though ca. 8,000 kinds of flavonoids have been reported in nature, anthocyanins, chalcones, aurones and some flavonols act as major flower pigments. Flavonoids are present as major components in many flowers. On the other hand, flavones and flavonols, which are colorless or extremely pale yellow, function as copigment substances. Moreover, expression of the flower colors is diversified by inter-molecular and intra-molecular copigmentation, metal chelation, pH change and so on. In this review, I describe the distribution of the flavonoids which act as the pigments, and contribution to flower colors, e.g., yellow, scarlet, red, red-purple, violet, purple, blue and so on, of flavonoids, especially anthocyanins, chalcones, aurones and flavonols.

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Mendoza, J. ; Oliveira, J. ; Araújo, P. ; Basílio, N. ; Teixeira, N. ; Brás, N. F. ; Pina, F. ; Yoshida, K. ; de Freitas, V. The Peculiarity of Malvidin 3-O-(6-O-P-Coumaroyl) Glucoside Aggregation. Intra and Intermolecular Interactions. Dyes Pigm. 2020, 180 , 108382, DOI: 10.1016/j.dyepig.2020.108382

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The peculiarity of malvidin 3-O-(6-O-p-coumaroyl) glucoside aggregation. Intra and intermolecular interactions

Mendoza, Johan; Oliveira, Joana; Araujo, Paula; Basilio, Nuno; Teixeira, Natercia; Bras, Natercia F.; Pina, Fernando; Yoshida, Kumi; de Freitas, Victor

Dyes and Pigments (2020), 180 (), 108382CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The aggregation of malvidin 3-O-(6-O-p-coumaroyl) glucoside flavylium cation (OeninCoum) in water is reported. Intra and intermol. interactions of OeninCoum were characterized by UV-vis absorption, 1H NMR and CD. Theor. calcns. were also performed to describe the intramol. interactions. At higher temp. (>60°C) the intermol. aggregates are disrupted but CD signal attributed to an intramol. interaction remains. Moreover, the kinetic and thermodn. data for Oenin and OeninCoum at 50°C and 25°C shows that the increase of temp. stabilizes the quinoidal base of this later.

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Qian, B. J. ; Liu, J. H. ; Zhao, S. J. ; Cai, J. X. ; Jing, P. The Effects of Gallic/Ferulic/Caffeic Acids on Colour Intensification and Anthocyanin Stability. Food Chem. 2017, 228 , 526– 532, DOI: 10.1016/j.foodchem.2017.01.120

[Crossref], [PubMed], [CAS], Google Scholar

The effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability

Qian, Bing-Jun; Liu, Jian-Hua; Zhao, Shu-Juan; Cai, Jian-Xiong; Jing, Pu

Food Chemistry (2017), 228 (), 526-532CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The mechanism by which copigments stabilize color, by protecting anthocyanin chromophores from nucleophilic attack, seems well accepted. This study was to det. effects of gallic/ferulic/caffeic acids on color intensification and anthocyanin stability. Mol. dynamics simulations were applied to explore mol. interactions. Phenolic acids intensified the color by 19% ∼ 27%. Color fading during heating followed first-order reactions with half-lives of 3.66, 9.64, 3.50, and 3.39 h, whereas anthocyanin degrdn., detd. by the pH differential method (or HPLC-PDA), followed second-order reactions with half-lives of 3.29 (3.40), 3.43 (3.39), 2.29 (0.39), and 2.72 (0.32) h alone or with gallic/ferulic/caffeic acids, resp., suggesting that anthocyanin degrdn. was faster than the color fading. The strongest protection of gallic acids might be attributed to the shortest distance (4.37 Å) of its arom. ring to the anthocyanin (AC) panel. Hyperchromic effects induced by phenolic acids were pronounced and they obscured the accelerated anthocyanin degrdn. due to self-assocn. interruption.

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Pina, F. ; Melo, M. J. ; Maestri, M. ; Passaniti, P. ; Balzani, V. Artificial Chemical Systems Capable of Mimicking Some Elementary Properties of Neurons. J. Am. Chem. Soc. 2000, 122 , 4496– 4498, DOI: 10.1021/ja000190d

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Artificial Chemical Systems Capable of Mimicking Some Elementary Properties of Neurons

Pina, Fernando; Melo, Maria Joao; Maestri, Mauro; Passaniti, Paolo; Balzani, Vincenzo

Journal of the American Chemical Society (2000), 122 (18), 4496-4498CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

We describe the photochem. behavior of aq. solns. contg. the Co(CN)63- complex ion and the trans-chalcone form Ct of the 4'-methoxyflavylium ion (AH+). It is shown that, under the exptl. conditions used, the photochem. reaction leading from Ct to AH+ shows an off-on-off behavior upon excitation with a continuous light source or with successive light flashes. The described systems perform as threshold devices and as XOR (exclusive OR) logic gates. They behave as rudimental artificial neuron-like systems in the sense that their outputs (formation of the AH+ species, with a consequent change in the spectroscopic properties) are the result of an elaboration of two distinct (light) inputs by chem. reactions in soln.

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Melo, M. J. ; Moura, S. ; Maestri, M. ; Pina, F. Micelle Effects on Multistate/Multifunctional Systems Based on Photochromic Flavylium Compounds. The Case of Luteolinidin. J. Mol. Struct. 2002, 612 , 245– 253, DOI: 10.1016/S0022-2860(02)00095-9

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Micelle effects on multistate/multifunctional systems based on photochromic flavylium compounds. The case of luteolinidin

Melo, Maria Joao; Moura, Sara; Maestri, Mauro; Pina, Fernando

Journal of Molecular Structure (2002), 612 (2-3), 245-253CODEN: JMOSB4; ISSN:0022-2860. (Elsevier Science B.V.)

The effect of the charged sodium dodecyl sulfate, cetyltrimethylammonium bromide and neutral N-benzyltrimethylammonium hydroxide (Triton X-100) on the thermal and light induced chem. of luteolinidin, a natural deoxyanthocyanidin found essentially in mosses and ferns, is described. The system was characterized by pH jump and flash photolysis techniques. While the kinetics and thermodn. of the cis-trans isomerization are only slightly affected, the hydration and proton transfer reactions are significantly changed by the presence of the charged surface of the micelles. On this basis the micelles can be considered as a third input, beside the pH variations and light pulses, capable of tuning some responses of this multistate/multifunctional system.

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Pina, F. ; Maestri, M. ; Balzani, V. Photochromic Flavylium Compounds as Multistate/Multifunction Molecular-Level Systems. Chem. Commun. 1999, 107– 114, DOI: 10.1039/a805522j

[Crossref], [CAS], Google Scholar

Photochromic flavylium compounds as multistate/multifunction molecular-level systems

Pina, Fernando; Maestri, Mauro; Balzani, Vincenzo

Chemical Communications (Cambridge) (1999), (2), 107-114CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

Synthetic flavylium compds. can exist in several forms (multistate) that can be interconverted by more than one type of external stimulus (multifunctional). The intricate network of their reactions, when examd. from the view point of 'mol.-level devices', reveals very interesting properties. Review with 34 refs.

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Melo, M. J. ; Moura, S. ; Roque, A. ; Maestri, M. ; Pina, F. Photochemistry of Luteolinidin: "Write-Lock-Read-Unlock-Erase" with a Natural Compound. J. Photochem. Photobiol., A 2000, 135 , 33– 39, DOI: 10.1016/S1010-6030(00)00272-0

[Crossref], [CAS], Google Scholar

Photochemistry of luteolinidin "Write-lock-read-unlock-erase" with a natural compound

Melo, M. J.; Moura, S.; Roque, A.; Maestri, M.; Pina, F.

Journal of Photochemistry and Photobiology, A: Chemistry (2000), 135 (1), 33-39CODEN: JPPCEJ; ISSN:1010-6030. (Elsevier Science S.A.)

In this work, the photochem. of luteolinidin, a natural deoxyanthocyanidin, found essentially in mosses and ferns is described. In moderately acidic methanol/water (3:1) solns. the dominant species of luteolinidin is the photoactive trans-chalcone. The system was characterized by steady state irradn. and pulse light excitation expts. as well as by pH jumps. The use of this compd. to carry out cycles able to write-lock-read-unlock-erase, is discussed.

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Bülow, C. ; Wagner, B. H. Ber. Dtsch. Chem. Ges. 1901, 34 , 1782– 1806, DOI: 10.1002/cber.19010340277

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Over derivatives of the 1.4-Benzopyranols, the source material of a new class of dyes II. [machine translation]

Buelow, Carl; Wagner, Hermann

Berichte der Deutschen Chemischen Gesellschaft (1901), 34 (), 1782-1804CODEN: BDCGAS; ISSN:0365-9496.

[Machine Translation of Descriptors]. The authors have in the first article (Ber. Dtsch. Chem. Ges. 34. 1189; C. 1901. I. 1326) condensation products from multi-valued phenols (resorcinol, phloroglucinol, pyrogallol) and acetylacetones described, which Anhydroderivate of the hypothetical 1.4-Benzopyranols (Formula I.) represents, (see original document for graphics). Recently the authors with Benzoylaceton represented the appropriate condensation products. With the cleavage by alkalis these compounds supply with on the one hand to acetophenone and on the other hand Resacetophenon, Phloracetophenon or Gallacetophenon, depending on resorcinol, phloroglucinol or pyrogallol for condensation were related. Therefore the constitutional Formulas II., III. and IV. come to the compounds, and it results that with coalescence of the Benzoylacetons with suitable phenols to Benzopyranolderivaten the phenyl group steps the methyl group regularly into zero position to the ring oxygen, however to it into p-position. The condensation products possess, like described the in former times, a coloring material character and form with hydrogen halide salt-like compounds, which dissociate into diluted solution; the picric acid compounds are somewhat steadier. The acetyl derivative of the Anhydro-2-phenyl-4-methyl-7-oxy-1.4-benzopyranols exists to a brown-red, crystallization, with difficult soluble form in two physical different modifications, white, amorphous, and easily soluble. Also the methylate product shows similar dimorphe features; from methylation by means of dimethyl sulfate in alkaline solution an amorphous, colorless product results; on the other hand iodine methyl produces a green-glossy, difficultly soluble, crystallinic compound. Anhydro-2-phenyl-4-methyl-7-oxy-1.4-benzopyranolchlorhydrat, C16H12O. HCl + H2O. Formation: One dissolves 11 g resorcinol and 16.2 g Benzoylaceton in 60 ccm glacial acetic acid and introduces under cooling dry HCl gas. After one hour becomes with water diluted, which recrystallize separated chlorine hydrate sucked off and from 150-200 ccm acidified, 40% alcohol; with rapid cool one the salt with 1 mole crystal water in yellow needles. By water partly dissociated; in acidified alcohol it separates easily, is otherwise, however, little soluble. The solution into concentrated sulfuric acid is yellowish and shows bluish- green fluorescence. From the acidified alcoholic-aqueous solution sodium acetate the base C16H12O2 precipitates in red, amorphous flakes. Picrinic acid additions product, C16H12O2. C6H6O7N3; prism tables crystals, little soluble in alcohol. Anhydro-2-phenyl-4-methyl-7-acetoxy-1.4-benzopyranol, C18H14O3. The asymmetrical white amorphous modification develops, if one of the chlorine hydrate below 30° in excess caustic potash solution dissolves and with shaking, adds drop by drop acetic anhydride. The compound sinters with 155-160° to a brown mass; they are easily soluble in organic means except ligroin. When cooking with acetic acid and acetic anhydride changes it into the crystallinic modification. The crystallinic modification develops when cooking 2 g chlorine hydrate with a mixture of 2 g anhydrous sodium acetate, 3 g acetic anhydride and 10 g glacial acetic acid. The compound crystallize from Nitrobenxyle in lamellas, which have a brown color, in the reflected a dark-green, in the broken light metallic gleam. It sinters only over 300°, is insoluble, however, by boiling aniline, nitrobenzene and pyridine is taken up in most solvents. The solution into concentrated sulfuric acid shows yellowish-green fluorescence. Anhydro-2-phenyl-4-methyl-7-methoxy-1.4-benzopyranol, C17H14O2. Asymmetrical amorphous modification. Formation: One loosens the chlorine hydrate of the coloring material cousin in acidified water, cools down, transferred with excess soda lye and adds below 30° Dimethyl sulfate in addition. The compound becomes from acetone precipitated by alcohol in white flakes. They are easily soluble in organic medium except ligroin and cold alcohol; it sinters with 120-125° to a brown resin together. The crystallinic modification develops, if 2 g of the chlorine hydrate in 20 ccm methyl alcohol with 3.1 g 10% methyl alcohol sodium solution and 1 g CH3J in the pipe 6 hours on 100-110° are heated up. Long needles from methyl alcohol, which show brown color in the falling through light, in the reflected dark-green metal gleam. Soluble in boiling aniline, nitrobenzene, pyridine, otherwise little soluble. The solution into concentrated sulfuric acid shows yellowish-green fluorescence the compound sinters with 260-261°. 2-Phenyl-4-methyl-7-oxybenzopyrane. Formation: By reduction of the Anhydro-2-phenyl-4-methyl-7-oxy-1.4-benzopyranolchlorhydrates with zinc and hydrochloric acid. Yellowish-white, amorphous powder, dried steadily, easily oxidizable in damp state easily oxydizible. Sinters with 155-160°. Insoluble in ligroin, otherwise easily soluble. Soluble in corroded alkalis, colorless. The solution into concentrated sulfuric acid is colorless, shows, however, green-yellow fluorescence. The acetyl derivative, C13H16O8, is amorphous, sinters with 115 to 120° and is easily soluble in organic medium. Anhydro-2-phenyl-4-methyl-5.7-dioxy-1.4-benzopyranolchlorhydrate, C16H12O3. HCl + H2O. Formation from phloroglucinol and Benzoylacetone in glacial acetic acid solution by HCl gas. Orange needles, blackens itself between 200 and 250° Few soluble in acidified alcohol, otherwise insoluble in organic medium. The solution into concentrated sulfuric acid does not fluoresce. The base C16H12O3, from which by means of potassium acetate recover chlorine hydrate, forms a red-brown, amorphous powder; few soluble in ethers, insoluble in ligroin; otherwise easily soluble. Picric acid compound, C16H12O3. C6H3O7N3; orange needles. Anhydro-2-phenyl-4-methyl-7.8-dioxy-1.4-benzopyranolchlorhydrate, C16H12O3. HCl. Formation from pyrogallol and Benzoylacetone in glacial acetic acid solution by HCl. Red-brown crystal, powder, consisting of rhombic tablets. Few soluble in acidified water and alcohol, otherwise insoluble in organic medium. Pure water causes Dissociation. Concetrated sulfuric acid draws with light-yellow color without fluorescence. The base C16H12O3 forms a black, crystallinic powder, which is with violet color in acetone, alcohol, chloroform, nitrobenzene and pyridine, soluble with red color in glacial acetic acid. Picric acid compound, C16H12O6. C6H6O7N3; dark-violet, hexagonal boards. The acetyl derivative, C20H16O5, from the chlorine hydrate represented by cooking with glacial acetic acid, acetic anhydride and sodium acetate, crystallize from nitrobenzene in red-brown, rectangular lamellas with green metal gleam, soluble in nitrobenzene, aniline, pyridine, otherwise very little soluble.

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Appelhagen, I. ; Wulff-Vester, A. K. ; Wendell, M. ; Hvoslef-Eide, A.-K. ; Russell, J. ; Oertel, A. ; Martens, S. ; Mock, H.-P. ; Martin, C. ; Matros, A. Colour Bio-Factories: Towards Scale-up Production of Anthocyanins in Plant Cell Cultures. Metab. Eng. 2018, 48 , 218– 232, DOI: 10.1016/j.ymben.2018.06.004

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Colour bio-factories: Towards scale-up production of anthocyanins in plant cell cultures

Appelhagen, Ingo; Wulff-Vester, Anders Keim; Wendell, Micael; Hvoslef-Eide, Anne-Kathrine; Russell, Julia; Oertel, Anne; Martens, Stefan; Mock, Hans-Peter; Martin, Cathie; Matros, Andrea

Metabolic Engineering (2018), 48 (), 218-232CODEN: MEENFM; ISSN:1096-7176. (Elsevier B.V.)

Anthocyanins are widely distributed, glycosylated, water-sol. plant pigments, which give many fruits and flowers their red, purple or blue coloration. Their beneficial effects in a dietary context have encouraged increasing use of anthocyanins as natural colorants in the food and cosmetic industries. However, the limited availability and diversity of anthocyanins com. have initiated searches for alternative sources of these natural colorants. In plants, high-level prodn. of secondary metabolites, such as anthocyanins, can be achieved by engineering of regulatory genes as well as genes encoding biosynthetic enzymes. We have used tobacco lines which constitutively produce high levels of cyanidin 3-O-rutinoside, delphinidin 3-O-rutinoside or a novel anthocyanin, acylated cyanidin 3-O-(coumaroyl) rutinoside to generate cell suspension cultures. The cell lines are stable in their prodn. rates and superior to conventional plant cell cultures. Scale-up of anthocyanin prodn. in small scale fermenters has been demonstrated. The cell cultures have also proven to be a suitable system for prodn. of 13C-labeled anthocyanins. Our method for anthocyanin prodn. is transferable to other plant species, such as Arabidopsis thaliana, demonstrating the potential of this approach for making a wide range of highly-decorated anthocyanins. The tobacco cell cultures represent a customisable and sustainable alternative to conventional anthocyanin prodn. platforms and have considerable potential for use in industrial and medical applications of anthocyanins.

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Levisson, M. ; Patinios, C. ; Hein, S. ; de Groot, P. A. ; Daran, J.-M. ; Hall, R. D. ; Martens, S. ; Beekwilder, J. Engineering De Novo Anthocyanin Production in Saccharomyces Cerevisiae. Microb. Cell Fact. 2018, 17 , 103, DOI: 10.1186/s12934-018-0951-6

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Engineering de novo anthocyanin production in Saccharomyces cerevisiae

Levisson, Mark; Patinios, Constantinos; Hein, Sascha; de Groot, Philip A.; Daran, Jean-Marc; Hall, Robert D.; Martens, Stefan; Beekwilder, Jules

Microbial Cell Factories (2018), 17 (), 103/1-103/16CODEN: MCFICT; ISSN:1475-2859. (BioMed Central Ltd.)

Background: Anthocyanins are polyphenolic pigments which provide pink to blue colors in fruits and flowers. There is an increasing demand for anthocyanins, as food colorants and as health-promoting substances. Plant prodn. of anthocyanins is often seasonal and cannot always meet demand due to low productivity and the complexity of the plant exts. Therefore, a system of on-demand supply is useful. While a no. of other (simpler) plant polyphenols have been successfully produced in the yeast Saccharomyces cerevisiae, prodn. of anthocyanins has not yet been reported. Results:Saccharomyces cerevisiae was engineered to produce pelargonidin 3-O-glucoside starting from glucose. Specific anthocyanin biosynthetic genes from Arabidopsis thaliana and Gerbera hybrida were introduced in a S. cerevisiae strain producing naringenin, the flavonoid precursor of anthocyanins. Upon culturing, pelargonidin and its 3-O-glucoside were detected inside the yeast cells, albeit at low concns. A no. of related intermediates and side-products were much more abundant and were secreted into the culture medium. To optimize titers of pelargonidin 3-O-glucoside further, biosynthetic genes were stably integrated into the yeast genome, and formation of a major side-product, phloretic acid, was prevented by engineering the yeast chassis. Further engineering, by removing two glucosidases which are known to degrade pelargonidin 3-O-glucoside, did not result in higher yields of glycosylated pelargonidin. In aerated, pH controlled batch reactors, intracellular pelargonidin accumulation reached 0.01 μmol/gCDW, while kaempferol and dihydrokaempferol were effectively exported to reach extracellular concn. of 20 μM [5 mg/L] and 150 μM [44 mg/L], resp. Conclusion: The results reported in this study demonstrate the proof-of-concept that S. cerevisiae is capable of de novo prodn. of the anthocyanin pelargonidin 3-O-glucoside. Furthermore, while current conversion efficiencies are low, a no. of clear bottlenecks have already been identified which, when overcome, have huge potential to enhance anthocyanin prodn. efficiency. These results bode very well for the development of fermn.-based prodn. systems for specific and individual anthocyanin mols. Such systems have both great scientific value for identifying and characterizing anthocyanin decorating enzymes as well as significant com. potential for the prodn. of, on-demand, pure bioactive compds. to be used in the food, health and even pharma industries.

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Zha, J. ; Koffas, M. A. G. Production of Anthocyanins in Metabolically Engineered Microorganisms: Current Status and Perspectives. Synth. Syst. Biotechnol. 2017, 2 , 259– 266, DOI: 10.1016/j.synbio.2017.10.005

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Production of anthocyanins in metabolically engineered microorganisms: Current status and perspectives

Zha Jian; Koffas Mattheos A G; Koffas Mattheos A G

Synthetic and systems biotechnology (2017), 2 (4), 259-266 ISSN:.

Microbial production of plant-derived natural products by engineered microorganisms has achieved great success thanks to large extend to metabolic engineering and synthetic biology. Anthocyanins, the water-soluble colored pigments found in terrestrial plants that are responsible for the red, blue and purple coloration of many flowers and fruits, are extensively used in food and cosmetics industry; however, their current supply heavily relies on complex extraction from plant-based materials. A promising alternative is their sustainable production in metabolically engineered microbes. Here, we review the recent progress on anthocyanin biosynthesis in engineered bacteria, with a special focus on the systematic engineering modifications such as selection and engineering of biosynthetic enzymes, engineering of transportation, regulation of UDP-glucose supply, as well as process optimization. These promising engineering strategies will facilitate successful microbial production of anthocyanins in industry in the near future.

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Perkin, W. H. ; Robinson, R. ; Turner, M. R. Cx.─the Synthesis and Constitution of Certain Pyranol Salts Related to Brazilein and Haematein. J. Chem. Soc., Trans. 1908, 93 , 1085– 1115, DOI: 10.1039/CT9089301085

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The Synthesis and Constitution of Certain Pyranol Salts Related to Brazilein and Haematein

Perkin, William Henry, Jr.; Robertson, Robert; Turner, Maurice Russell

Journal of the Chemical Society, Transactions (1908), 93 (), 1085-1114CODEN: JCHTA3; ISSN:0368-1645.

For abstract of preliminary report see Proc.Chem.Soc., 23, 149; and C. A., 1908, 109, 1005, 1562, and 1968. Acetophenone and β-resorcylaldehyde condense in AcOH by HCl to 7-hydroxy-2-phenylbenzopyranol-1,4-anhydrohydrochloride (I), decomp. 152°, identical with HCl salt, m. 152-3° of B.ovrddot.ulow and Sicherer (Ber., 34, 3889); chlorplatinate, (C15H11O2Cl2)PtCl4,2H2O, and recrystallized from formic acid (C15H11O2Cl)2PtCl4. Oxonium salt (II) resulting on boiling 2'-hydroxybenzylidene-α-hydrindone in EtOH with HCl, yields with FeCl3 2,3-indenobenzopyranol-1,4-anhydroferrichloride (III), m. 175°; chlorplatinate. 7-Hydroxy-2,3-indenobenzopyranol-1,4-anhydrohydrochloride, from the condensation of β-resorcylaldehyde with α-hydrindone, or by passing HCl through a solution of 2',4'-dihydroxy-2-benzylidene-1-hydrindone in MeOH, brownish-orange prisms, 3H2O, softens 105°; chlorplatinate; chloraurate, two modifications, (C16H11O2Cl)AuCl3,2H2O and after recrystallization from MeOH-HCl, (C16H11O2Cl)2AuCl3; anhydroferrichloride, darkens 165°, m. 171°. The Pt and Au salts are (pyranol, HCl)2PtCl4 (IV), and on recrystallization from dil. HCl, they lose H2O and have the composition (pyranol, HCl-H2O)2PtCl4 (III). All the ferrichlorides are of the type (III). The last-mentioned HCl salt when treated with NaOAc yields the pyranol base, 7-hydroxy-2,3-indenobenzopyranol-1,4 (V), and when treated with KOH it is hydrolyzed into α-hydrindone. When 2'-hydroxy-4'-methoxy-2-benzylidene-1-hydrindone is treated with HCl and finally FeCl3, 7-methoxy-2,3-indenobenzopyranol-1,4-anhydroferrichloride results, m. 163° (with decomp.). Salicylaldehyde and 5,6-dimethoxy-1-hydrindone yield 4',5'-dimethoxy-2,3-indenobenzopyranol-1,4-anhydrohydrochloride, darkens 135°, decomp. 165°; chlorplatinate, 2H2O; anhydroferrichloride; KOH hydrolyzes the HCl salt of this pyranol into 2'-hydroxy-5,6-dimethoxy-2-benzylidene-1-hydrindone, which is readily converted into the pyranol anhydrohydrochloride again. 4',5'-Methylenedioxy-2,3-indenobenzopyranol-1,4-anhydroferrichloride, from 2'-hydroxy-5,6-methylenedioxy-2-benzylidene-1-hydrindone, m. 225° (indistinctly). 7-Hydroxy-4',5'-dimethoxy-2,3-indenobenzopyranol-1,4-anhydrohydrochloride, from 2',4'-dihydroxy-5,6-dimethoxy-2-benzylidene-1-hydrindone or from β-resorcylaldehyde and 5,6-dimethoxyhydrindone, crimson prisms or short needles, darkens 200°; NaOAc precipitates from its solution the pyranol base; chlorplatinate, anhydroferrichloride. 4',5',7-Trimethoxy-2,3-indenobenzopyranol-1,4-anhydrohydrochloride, from p-methoxysalicylaldehyde and dimethoxyhydrindone, darkens 175°; chlorplatinate; anhydroferrichloride, bright red needles, m. about 200° (with decomp.); anhydrocadmium bromide, vermillion-red salt; KOH hydrolyzes the HCl salt to 2'-hydroxy-4',5,6-trimethoxy-2-benzylidene-1-hydrindone, which substance is readily reconverted into the pyranol anhydrohydrochloride. Resacetophenone dimethyl ether (Tahara, Ber., 24, 2461) has been prepared by methylation of resacetophenone with (Me)2SO4 and KOH, b. 288°, crystals (from MeOH), m. 40°. 2-Hydroxy-2',4'-dimethoxybenzylideneacetophenone (VI), from salicylaldehyde and resacetophenone, small, yellow needles or prisms (from EtOH), m. 124°; potassium derivative, orange-red crystals; When this ketone is boiled in AcOH with conc. HCl for a few minutes 2-phenylbenzopyranolanhydrohydrochloride results; chlorplatinate. If dry HCl is passed into dry (Et)2O solution of the ketone in the cold for 3 hrs., the dichloride (VII) results; yellow needles, soften 78°, m. 85° (with decomp.). The hydrochloride of 4'-methoxy-2-phenylbenzopyranol-1,4-anhydrohydrochloride is obtained from 2-hydroxy-4'-methoxybenzylideneacetophenone (Kostanecki and Zwayer, Ber., 41, 1337) under similar conditions as for the preceding dichloride, orange-red needles, m. 126° (with decomp.). 4'-Methoxy-2-phenylbenzopyranol-1,4-anhydrohydrochloride, from the dichloride by dissolving the latter in H2O and allowing to stand, orange crystals, m. 87°, may also be prepared from 2-hydroxy-4'-methoxybenzylideneacetophenone; anhydrochlorplatinate; anhydroferrichloride, by the addition of conc. FeCl3 solution to a solution of the HCl salt, needles, m. 156°; another method of formation of this ferrichloride consists in the addition of conc. FeCl3 in HCl to an AcOH solution of 2-hydroxy-4'-methoxybenzylideneacetophenone, when on adding more HCl, a red compound (VIII) is precipitated; H2O decomposes it into the ketone again. When boiled in AcOH solution, the color changes from red to yellow and the above anhydroferrichloride of the pyranol results. The ferrichloride of the hydrochloride of 2-hydroxy-2',4'-dimethoxybenzylideneacetophenone (constitution like VIII) from 2-hydroxy-2',4'-dimethoxybenzylideneacetophenone. The hydrochloride of 2',4'-dimethoxy-2-phenylbenzopyranolanhydrohydrochloride, from the above ketone, m. 116°. 2',4'-Dimethoxy-2-phenylbenzopyranol-1,4-anhydrochloride yields a chlorplatinate, and a ferrichloride, red needles, m. 189°. The authors give to the anhydrochlorides of these pyranols the o-quinoid structure (I) instead of (IX) as proposed by Decker (Ann., 356, 302 and C. A., 1908, 537), on account of their color properties.

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Pratt, D. D. ; Robinson, R. Clxxxviii.-a Synthesis of Pyrylium Salts of Anthocyanidin Type. J. Chem. Soc., Trans. 1922, 121 , 1577– 1585, DOI: 10.1039/CT9222101577

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Synthesis of pyrylium salts of the anthocyanidin type

Pratt, D. D.; Robinson, Robert

Journal of the Chemical Society, Transactions (1922), 121 (), 1577-85CODEN: JCHTA3; ISSN:0368-1645.

All pyrylium salts thus far synthesized have been substituted in the pyrylium nucleus by various alkyl and aryl groups. Since Willst.ovrddot.atter has shown that the naturally occurring plant pigments are derived from 3-hydroxybenzopyrylium, it is of interest to attempt synthesis of compds. of this type. Phenyl 2-hydroxy-β-ethoxystyryl ketone, HOC6H4CH:C(OEt)COPh, from HOC6H4CHO and EtOCH2COPh in MeOH-KOH, glistening leaflets, m. 138°; the concd. H2SO4 soln. is bright orange-red, the KOH soln. orange-yellow. With HCl in Et2O and subsequent addn. of FeCl3 it is transformed into 3-ethoxy-2-phenylbenzopyrylium ferrichloride, bright golden plates, m. 121°. The yellow soln. in concd. H2SO4 has a pale ivy-green fluorescence. Phenyl 2-hydroxy-β-phenoxystyryl ketone, silvery rhombic prisms, m. 160°. 3-Phenoxy-2-phenylbenzopyrylium ferrichloride, golden yellow, hexagonal prisms, m. 149°. 7-Hydroxy-3-ethoxy-2-phenylbenzopyrylium chloride, from 2,4-(HO)2C6H3CHO and EtOCH2COPh in AcOH and HCl, clusters of orange-red needles, decomp. 210°. It is at once hydrolyzed by water, giving a deep crimson product. Chloroplatinate, small, bright red needles, decomp. 225°. Ferrichloride, orange-red, diamond-shaped prisms, m. 170°. Mercurichloride, orange-red needles, m. 188°. Iodide, red, elongated prismatic needles, with no definite m. p. Periodide, almost black needles. Perchlorate, orange-yellow hexagonal prisms, m. 248° (decompn.). Picrate, small red prisms, decomp. 215°. 7-Hydroxy-3-pkenoxy-2-phenylbenzopyrylium ferrichloride, small bright red tablets, with beetle-green luster, m. 178°.

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Pratt, D. D. ; Robinson, R. A Synthesis of Pyrylium Salts of Anthocyanidin Type. Part V. The Synthesis of Cyanidin Chloride and of Delphinidin Chloride. J. Chem. Soc., Trans. 1925, 127 , 166– 175, DOI: 10.1039/CT9252700166

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Synthesis of pyrylium salts of anthocyanidin type. V. The synthesis of cyanidin chloride and of delphinidin chloride

Pratt, D. D.; Robinson, Robt.

Journal of the Chemical Society, Transactions (1925), 127 (), 166-75CODEN: JCHTA3; ISSN:0368-1645.

cf. C. A. 18, 986. Et α,γ-dimethoxyacetoacetate (I), b15 130°, from Na and MeOCH2CO2Et; its EtOH soln. gives a violet color with FeCl3. Me ester, b17 129°. I (22.3 g.), 2.7 g. Na and 20 g. p-MeOC6H4COCl gave 7.5 g. p-MeOC6H4-COCH2OMe, m. 40°, which condensed with 6-aminopiperonal in EtOH to give 3-methoxy-6,7-methylenedioxy-2-[4-methoxyphenyl]quinoline, m. 152°. 3,4-(MeO)2C6H8-COCl (38 g.) similarly gave 22 g. ω-methoxyacetoverathrone (II), b15 190°, m. 62°; its semicarbazone, m. 178° (cf. C. A. 17, 2288). 3-Methoxy-6,7-methylenedioxy-2-[3,4-dimethoxyphenyl]quinoline m. 155°; the EtOH soln. has a violet fluorescence. II and β-resorcylaldehyde in dry Et2O, treated with HCl gas, give fisetinidin chloride trimethyl ether; from hot 7% HCl there sep. reddish brown needles with 2H2O, exhibiting a green reflex, darken 135°, decomp. 188-9°. The EtOH soln. is deep reddish violet and the orange concd. H2SO4 soln. exhibits a green fluorescence. The violet color base is pptd. when AcONa is added to the moderately concd. aq. soln. of the salt but if a dil. soln. is used the appearance of the violet color is transient and the ψ-base is obtained. II and 2,4,6-HO(MeO)2C6H2CHO give cyanidin chloride pentamethyl ether, crystg. from 7% HCl in long orange-brown needles with 3H2O; the HCl salt crysts. from EtOH with 2H2O, red needles, m. 152°; the ferrichloride is reddish brown, exhibiting a bronze luster and m. 194-200° (decompn.). When this ether is heated with PhOH and HI, there results cyanidine chloride, identical with a specimen of natural origin. ω-3,4,5-Tetramethoxyacetophenone (II), b15 212°, m. 54° (semicarbazone, m. 158°), results from 24.5 g. 3,4,5-(MeO)3C6H2COCl and I in a 9 g. yield. 3-Methoxy-6,7-methylenedioxy-2-[3,4,5-trimethoxyphenyl]quinoline, m. 159°, and shows a violet fluorescence in EtOH. The HCl salt is yellow, the methosulfate, orange-yellow. III and 2,4,6-HO(MeO)2-C6H2CHO with HCl give delphinidin chloride hexamethyl ether, long red needles with 0.5 H2O, m. 163-4°; it exhibits a green luster and is reddish violet by transmitted light. The ferrichloride is brownish red, the sulfate red with a green reflex. With HI and PhOH this gives delphinidin chloride, identical with the natural product.

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Robertson, A. ; Robinson, R. Ccxxv.─Experiments on the Synthesis of Anthocyanins. Part I. J. Chem. Soc. 1926, 129 , 1713– 1720, DOI: 10.1039/JR9262901713

Kueny-Stotz, M. ; Chassaing, S. ; Brouillard, R. ; Nielsen, M. ; Goeldner, M. Flavylium Salts as in Vitro Precursors of Potent Ligands to Brain Gaba-a Receptors. Bioorg. Med. Chem. Lett. 2008, 18 , 4864– 4867, DOI: 10.1016/j.bmcl.2008.07.107

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Flavylium salts as in vitro precursors of potent ligands to brain GABA-A receptors

Kueny-Stotz, Marie; Chassaing, Stefan; Brouillard, Raymond; Nielsen, Mogens; Goeldner, Maurice

Bioorganic & Medicinal Chemistry Letters (2008), 18 (17), 4864-4867CODEN: BMCLE8; ISSN:0960-894X. (Elsevier Ltd.)

The synthesis of a series of derivatized flavylium cations was undertaken and the affinity to the benzodiazepine binding site of the GABA-A receptor evaluated. The obsd. high affinity for some derivs. (sub-μM range) was explained by an in vitro transformation of the flavylium cations into the corresponding trans-retrochalcones, components which are proposed to be the active species in this series.

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Diniz, A. M. ; Gomes, R. ; Parola, A. J. ; Laia, C. A. T. ; Pina, F. Photochemistry of 7-Hydroxy-2-(4-Hydroxystyryl)-1-Benzopyrylium and Related Compounds. J. Phys. Chem. B 2009, 113 , 719– 727, DOI: 10.1021/jp807024d

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Photochemistry of 7-Hydroxy-2-(4-hydroxystyryl)-1-benzopyrylium and Related Compounds

Diniz, Ana M.; Gomes, Raquel; Parola, A. Jorge; Laia, Cesar A. T.; Pina, Fernando

Journal of Physical Chemistry B (2009), 113 (3), 719-727CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)

2-Styryl-1-benzopyrylium derivs. exhibit deeper hues and absorption spectra that are substantially red-shifted when compared with their 2-phenyl-1-benzopyrylium analogs. They follow the same pH and light-dependent network of chem. reactions previously described for 2-phenyl-1-benzopyrylium compds. In this work, the photochromic properties of 7-hydroxy-2-(4-hydroxystyryl)-1-benzopyrylium chloride are reported. This compd. was fully characterized by UV-vis absorption, fluorescence emission, pH jumps, and flash photolysis, and its properties were compared with the analog 7,4'-dihydroxyflavylium (7-hydroxy-2-(4-hydroxyphenyl)-1-benzopyrylium). The trans-chalcones of both compds. lacking the hydroxyl in position 2 were synthesized and used as model compds. since they exhibit cis-trans isomerization but cannot be involved in the other processes resulting from the ring closure. The transient absorption of two triplets attributed to the chalcones Ct/Ct-, and a tautomer was detected by nanosecond flash photolysis, independent of the existence of the 2-hydroxyl substituent. The exptl. results are compatible with the main formation of cis-chalcone from the singlet state. In the case of the styryl derivs., the fraction of triplet formed from excitation of Ct is much higher, and the fraction of isomerization is much smaller. For this reason, the photochem. of 7-hydroxy-2-(4-hydroxystyryl)-1-benzopyrylium in water is much less efficient than that of its parent 7,4'-dihydroxyflavylium; however, in the presence of CTAB micelles, intense red colors can be obtained upon irradn., confirming the usefulness of this family of compds. as photochromic systems.

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Gomes, R. ; Diniz, A. M. ; Jesus, A. ; Parola, A. J. ; Pina, F. The Synthesis and Reaction Network of 2-Styryl-1-Benzopyrylium Salts: An Unexploited Class of Potential Colorants. Dyes Pigm. 2009, 81 , 69– 79, DOI: 10.1016/j.dyepig.2008.09.007

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The synthesis and reaction network of 2-styryl-1-benzopyrylium salts: An unexploited class of potential colorants

Gomes, Raquel; Diniz, Ana M.; Jesus, Alexandre; Parola, A. Jorge; Pina, Fernando

Dyes and Pigments (2009), 81 (1), 69-79CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The syntheses, thermodn. and kinetic properties of a series of 2-styryl-1-benzopyrylium compds. are reported. This family of compds. was found to follow the same pH- and light-dependent network of chem. reactions previously described for flavylium (2-phenyl-1-benzopyrylim) compds. However, 2-styryl-1-benzopyrylium compds. exhibit absorption spectra substantially red shifted when compared with flavylium analogs (up to 90 nm). In particular, a photochromic system switching from yellow to light blue based on derivs. of natural anthocyanins is for the first time documented.

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Gomes, V. ; Mateus, N. ; de Freitas, V. ; Cruz, L. Synthesis and Structural Characterization of a Novel Symmetrical 2,10-Bis-Styryl-1-Benzopyrylium Dye. Synlett 2018, 29 , 1390– 1394, DOI: 10.1055/s-0036-1591978

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Synthesis and Structural Characterization of a Novel Symmetrical 2,10-Bis-Styryl-1-Benzopyrylium Dye

Gomes, Vania; Mateus, Nuno; de Freitas, Victor; Cruz, Luis

Synlett (2018), 29 (10), 1390-1394CODEN: SYNLES; ISSN:0936-5214. (Georg Thieme Verlag)

A novel sym. 2,10-bis-styryl-1-benzopyrylium dye was synthesized through two steps: in the first reaction an aldol condensation between 2,4,6-trihydroxybenzaldehyde and 3,4-dihydroxymethylstyrylketone gave 5,7,3',4'-tetrahydroxy-2-styryl-1-benzopyrylium; and in the second step this latter reacted with the same ketone by a cycloaddn. reaction yielding the sym. 2,10-bis(3,4-dihydroxystyryl)-pyrano-7-hydroxy-1-benzopyrylium. The dye was fully characterized by LC-DAD/ESI-MS and NMR 1D and 2D techniques, and a formation pathway was proposed. The novel dye obtained revealed extended π-conjugation (λ max556 nm) and catechol groups in its compn., which is very important for applications as a photosensitizer for dye-sensitive solar cells (DSSCs).

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Mora-Soumille, N. ; Al Bittar, S. ; Rosa, M. ; Dangles, O. Analogs of Anthocyanins with a 3′,4′-Dihydroxy Substitution: Synthesis and Investigation of Their Acid–Base, Hydration, Metal Binding and Hydrogen-Donating Properties in Aqueous Solution. Dyes Pigm. 2013, 96 , 7– 15, DOI: 10.1016/j.dyepig.2012.07.006

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Analogs of anthocyanins with a 3',4'-dihydroxy substitution: Synthesis and investigation of their acid-base, hydration, metal binding and hydrogen-donating properties in aqueous solution

Mora-Soumille, Nathalie; Al Bittar, Sheiraz; Rosa, Maxence; Dangles, Olivier

Dyes and Pigments (2013), 96 (1), 7-15CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Glycosides of hydroxylated flavylium ions are proposed as pertinent analogs of anthocyanins, a major class of polyphenolic plant pigments. Anthocyanins with a 3',4'-dihydroxy substitution on the B-ring (catechol nucleus) are esp. important for their metal chelating and electron-donating (antioxidant) capacities. In this work, an efficient chem. synthesis of 3',4'-dihydroxy-7-O-β-D-glucopyranosyloxyflavylium chloride and its aglycon is reported. Then, the ability of the two pigments to undergo proton transfer (formation of colored quinonoid bases) and add water (formation of a colorless chalcone) is investigated: at equil. the colored quinonoid bases (kinetic products) are present in very minor concns. (<10% of the total pigment concn.) compared to the colorless chalcone (thermodn. product). The glucopyranosyloxyflavylium ion appears significantly less acidic than the aglycon. The thermodn. of the overall sequence of flavylium-chalcone conversion is not affected by the β-D-glucosyl moiety while the kinetics appears slower by a factor ca. 8. Although the glucopyranosyl-oxyflavylium ion and its aglycon display similar affinities for Al3+, the Al3+-glucoside complex is more stable than the Al3+-aglycon complex due to the higher sensitivity of the latter to water addn. and conversion into the corresponding chalcone. Finally, the glucopyranosyl-oxyflavylium ion and its aglycon are compared for their ability to reduce the 1,1-diphenyl-2-picrylhydrazyl radical in a mildly acidic water/MeOH (1:1) mixt. as a first evaluation of their antioxidant activity. Glycosidation at C7-OH results in a lower rate const. of first electron transfer to DPPH and a lower stoichiometry (total no. of 1,1-diphenyl-2-picrylhydrazyl radicals reduced per pigment mol.). Anthocyanins are difficult to ext. from plants in substantial amt. However, the analogs investigated in this work are of easy access by chem. synthesis and express the physico-chem. properties typical of anthocyanins. They can thus be regarded as valuable models for investigating the coloring, metal-binding and antioxidant properties of these important natural pigments.

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Barcena, H. S. ; Chen, P. ; Tuachi, A. Synthetic Anthocyanidins and Their Antioxidant Properties. SpringerPlus 2015, 4 , 499, DOI: 10.1186/s40064-015-1250-x

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Synthetic anthocyanidins and their antioxidant properties

Barcena Homar S; Chen Peishan; Tuachi Abraham

SpringerPlus (2015), 4 (), 499 ISSN:2193-1801.

Anthocyanidins were synthesized to study the effect of methoxy substitution on the B ring to their antioxidant property. Comparative FRAP studies show 2'- and 4'-methoxy substituents have higher antioxidant activities, which may be attributed to both resonance and inductive effects.Graphical abstract:Anthocyanidins as reducing agents.

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Cruz, L. ; Mateus, N. ; De Freitas, V. First Chemical Synthesis Report of an Anthocyanin Metabolite with in Vivo Occurrence: Cyanidin-4′-O-Methyl-3-Glucoside. Tetrahedron Lett. 2013, 54 , 2865– 2869, DOI: 10.1016/j.tetlet.2013.03.100

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First chemical synthesis report of an anthocyanin metabolite with in vivo occurrence: cyanidin-4'-O-methyl-3-glucoside

Cruz, Luis; Mateus, Nuno; de Freitas, Victor

Tetrahedron Letters (2013), 54 (22), 2865-2869CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

A strategy was reported for the chem. synthesis of cyanidin-4'-O-methyl-3-glucoside, which involved the 'Western' and 'Eastern' mols., namely 2,4-diacetoxy-6-hydroxybenzaldehyde (I) and 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyloxy)-3'-benzyloxy-4'-methoxyacetophenone (II), resp. The final step consisted in Robinson's acidic aldol condensation between I and II, yielding, after deprotection, the title product.

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Cruz, L. ; Fernandes, I. ; Évora, A. ; de Freitas, V. ; Mateus, N. Synthesis of the Main Red Wine Anthocyanin Metabolite: Malvidin-3-O-Β-Glucuronide. Synlett 2017, 28 , 593– 596, DOI: 10.1055/s-0036-1588673

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Synthesis of the Main Red Wine Anthocyanin Metabolite: Malvidin-3-O-β-Glucuronide

Cruz, Luis; Fernandes, Iva; Evora, Ana; de Freitas, Victor; Mateus, Nuno

Synlett (2017), 28 (5), 593-596CODEN: SYNLES; ISSN:0936-5214. (Georg Thieme Verlag)

Anthocyanins are widely consumed in human and despite the health effects that have been attributed to them they appear to have low plasmatic concn. This is in great part attributed to the lack of stds. to allow an adequate assignment of the identity of the compds. detected that are often not the ones present in the original source. In this work, the chem. synthesis strategy of one of the glucuronide conjugates of the main anthocyanin present in red wine was developed. The purity and the identity of the metabolite were checked by HPLC-DAD, LC-MS, and NMR spectroscopy. It was confirmed that the compd. obtained was malvidin-3-O-β-glucuronide, with the main MS2 and MS3 fragments corresponding to the loss of glucuronic moiety [M - 176]+m/z = 331 and Me groups [M - 176 - 16]+m/z = 315. The configuration and the position of the linkage between the aglycon and the glucuronyl residue was confirmed by NMR spectroscopy, considering the coupling const. between H-C1'' and H-C2'' and HMBC/NOESY connectivities.

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Zhang, Q. ; Botting, N. P. ; Kay, C. A Gram Scale Synthesis of a Multi-¹³c-Labelled Anthocyanin, [6,8,10,3′,5′-¹³c₅]Cyanidin-3-Glucoside, for Use in Oral Tracer Studies in Humans. Chem. Commun. 2011, 47 , 10596– 10598, DOI: 10.1039/c1cc14323a

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A gram scale synthesis of a multi-13C-labelled anthocyanin, [6,8,10,3',5'-13C5]cyanidin-3-glucoside, for use in oral tracer studies in humans

Zhang, Qingzhi; Botting, Nigel P.; Kay, Colin

Chemical Communications (Cambridge, United Kingdom) (2011), 47 (38), 10596-10598CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

The major dietary anthocyanin, cyanidin-3-glucoside, was prepd. on a 4 g scale from three units of di-Et [2-13C]malonate and one unit of [1,3-13C2]acetone, such that five isotope locations were distributed throughout the mol. to provide a penta-13C5-labeled anthocyanin, [6,8,10,3',5'-13C5]cyanidin-3-glucoside chloride, for use in human stable-isotope tracer studies.

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Cruz, L. ; Basílio, N. ; Mateus, N. ; Pina, F. ; de Freitas, V. Characterization of Kinetic and Thermodynamic Parameters of Cyanidin-3-Glucoside Methyl and Glucuronyl Metabolite Conjugates. J. Phys. Chem. B 2015, 119 , 2010– 2018, DOI: 10.1021/jp511537e

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Characterization of Kinetic and Thermodynamic Parameters of Cyanidin-3-glucoside Methyl and Glucuronyl Metabolite Conjugates.

Cruz, Luis; Basilio, Nuno; Mateus, Nuno; Pina, Fernando; de Freitas, Victor

Journal of Physical Chemistry B (2015), 119 (5), 2010-2018CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

The detn. of rate and equil. consts. of anthocyanin metabolites with in vivo occurrence, cyanidin-4'-O-methyl-3-glucoside (Cy4'Me3glc) and cyanidin-7-O-glucuronyl-3-glucoside (Cy7Gluc3glc), was carried out for the first time by means of direct and reverse pH jumps. The thermodn. and kinetics of these compds. are similar to the anthocyanin monoglucosides in particular for the analogous cyanidin-3-glucoside (Cy3glc) and peonidin-3-glucoside (Peo3glc). The rate and equil. consts. of metabolites were also compared with malvin (malvidin 3,5-diglucoside) and with a bio-inspired compd. 3',4'-dihydroxy-7-O-glucopyranosyloxyflavylium (DGF). In Cy4'Me3glc and Cy7Gluc3glc the rate of hydration for a fixed pH value is slower than in DGF and the dominant species at moderately acidic solns. is the hemiketal. Oppositely, in DGF trans-chalcone is the dominant species at moderately acidic solns.

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Robertson, A. ; Robinson, R. Experiments on the Synthesis of Anthocyanins. Part V. A Synthesis of 3-B-Glucosidylpelargonidin Chloride, Which Is Believed to Be Identical with Callistephin Chloride. J. Chem. Soc. 1928, 0 , 1460– 1472, DOI: 10.1039/JR9280001460

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Synthesis of anthocyanins. V. Synthesis of 3,β-glucosidylpelargonidin chloride, which is believed to be identical with callistephin chloride

Robertson, A.; Robinson, R.

Journal of the Chemical Society (1928), (), 1460-72CODEN: JCSOA9; ISSN:0368-1769.

p-HOC6H4COCH2OH and ClCO2Me in H2O give ω-hydroxy-4-methylcarbonato-acetophenone, m. 84°; 4-Ac deriv. (III), m. 95-6°; 4-Bz deriv. (IV), m. 140-1°; the di-Bz deriv., m. 180-2°. IV (4.5 g.) and 12 g. O-tetraacetyl-α-glucosidyl bromide (V) in 80 cc. C6H6, treated with 10 g. Ag2CO3 at 35°, give 5 g. ω-O-tetraacetyl-β-glucosidoxy-4-benzoyloxyacetophenone, m. 147°, attempts to condense this with I were not successful. III and V similarly give the 4-Ac deriv. (VI), m. 132°. ω-O-Tetraacetyl-β-glucosidoxy-4-methoxyacetophenone, m. 133°, from V and anisoylcarbinol. VI (1 g.) and 1.5 g. I in 30 cc. CHCl3 and 100 cc. Et2O, satd. with HCl at room temp., give 0.4 g. pure and 0.6 g. impure 3-O-tetraacetyl-β-glucosidoxy-7-hydroxy-5-benzcyloxy-4'-acetoxyflavylium chloride, red plates with brilliant green reflex; the orange-red EtOH soln. shows a green fluorescence; NaOH or concd. aq. Na2CO3 gives a purple-violet color. With 8% NaOH at 10° for 3 hrs., followed by acidification with 7% HCl until the concn. of the HCl was 2%, purification through the Pb salt and addn. of cold satd. aq. picric acid, there results 3-β-glucosidylpelargonidin picrate, bright red plates with a brilliant golden reflex; with 5% MeOH-HCl this gives the chloride, which crysts. with 2H2O and in every respect appears to be identical with the callistephin chloride of Willst.ovrddot.atter and Burdick. If this be true, then pelargonin, peonin and cyanin are 5- or 7-saccharides, the weight of evidence favoring the 5-saccharide configuration.

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Murakami, S. ; Robertson, A. ; Robinson, R. Ccclxxii.─Experiments on the Synthesis of Anthocyanins. Part Vi. A Synthesis of Chrysanthemin Chloride. J. Chem. Soc. 1931, 0 , 2665– 2671, DOI: 10.1039/JR9310002665

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Synthesis of anthocyanins. VI. Synthesis of chrysanthemin chloride

Murakami, Shinzo; Robertson, Alex; Robinson, Robert

Journal of the Chemical Society (1931), (), 2665-71CODEN: JCSOA9; ISSN:0368-1769.

cf. C. A. 22, 3411. 3,4-(HO)2C6HaCOCH2OH (5 g. of the Na salt) in 25 cc. H2O, shaken in the cold with 5 cc. Ac2O and 10 cc C6H6, gives 3.9. g. of ‾ω-hydroxy-3,4-diacetoxy-acetophenone, m. 86-7°, sepd. as the CaCl2 compd., 2 C12H12O6. CaCl2, m. 126-7°; with dry Ag2CO3 and O-tetraacetyl-α-glucosidyl bromide in CHCl3, agitated for 15 min. and then refluxed 15 min., there results ‾ω-O-tetraacetyl-β-glucosidoxy-3,4-diacetoxyacetophenone (I), m. 105-5.5°. I and O-benzoylphloroglucinaldehyde in CHCl3-Et2O, satd. with HCl at room temp., give tetraacetylglucosidoxybenzoyloxyhydroxydiacetoxy-flavyliurn chloride, dark red; this was dissolved in 10% NaOH, allowed to stand 3.5 hrs. at room temp., acidified with 10% HCl, kept 12 hrs., the BzOH filtered off, the pyrylium salt converted into the Pb salt, regenerated and changed into 3-β-glucosidoxy-5,7,3',4'-tetrahydroxyflavylium picrate, deep brownish red with feeble metallic glance, m. 178°, decomps. 182°; this was also obtained in EtOAc, from which the picrate sepd. as prisms, orange by transmitted light and crimson with bronze glance in mass, m. 170-5° according to the rate of heating, and decompg. 190-3°, crystg. with 4 mols. H2O. With 2% MeOH-HCl this yields 3-β-glucosidylcyanidin chloride (chrysanthemin chloride), identical with that obtained by Willst.ovrddot.atter from the deep-red chrysanthemum. Color reactions are given for a range of buffered solns. of graded pH.

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Dangles, O. ; Elhajji, H. Synthesis of 3-Methoxy-Flavylium and 3-(B-D-Glucopyranosyloxy)Flavylium Ions - Influence of the Flavylium Substitution Pattern on the Reactivity of Anthocyanins in Aqueous-Solution. Helv. Chim. Acta 1994, 77 , 1595– 1610, DOI: 10.1002/hlca.19940770616

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Synthesis of 3-methoxy- and 3-(β-D-glucopyranosyloxy)flavylium ions. Influence of the flavylium substitution pattern on the reactivity of anthocyanins in aqueous solution

Dangles, Olivier; Elhajji, Hakima

Helvetica Chimica Acta (1994), 77 (6), 1595-610CODEN: HCACAV; ISSN:0018-019X.

The synthesis of 3-glycosyloxylated flavylium ions (anthocyanins), in particular of callistephin, a natural anthocyanin, is described. The structural transformations in aq. soln. and mol. complexation with chlorogenic acid and caffeine of the synthesized pigments, e.g. I (R = H, OH), are investigated. The results are discussed in terms of the role played by the glycosyloxy residues in the chem. properties of anthocyanins. Anthocyanin mol. complexation (copigmentation) is investigated by UV/VIS spectroscopy and 1H-NMR. In particular, the UV/VIS spectroscopic data are interpreted using a general theor. treatment, which, e.g., allows to demonstrate the formation of mol. complexes between the colorless forms of an anthocyanin and caffeine.

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Kuhnert, N. ; Clifford, M. N. ; Radenac, A. G. Boron Trifluoride-Etherate Mediated Synthesis of 3-Desoxyanthocyanidins Including a Total Synthesis of Tricetanidin from Black Tea. Tetrahedron Lett. 2001, 42 , 9261– 9263, DOI: 10.1016/S0040-4039(01)01975-X

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Boron trifluoride-etherate mediated synthesis of 3-desoxyanthocyanidins including a total synthesis of tricetanidin from black tea

Kuhnert, Nikolai; Clifford, Mike N.; Radenac, Anne-Gaelle

Tetrahedron Letters (2001), 42 (52), 9261-9263CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

The synthesis of a series of 3-desoxyanthocyanidins, e.g. I, via a BF3·Et2O-mediated aldol condensation between a substituted acetophenone and salicylaldehyde derivs. is described. Using this new synthetic methodol. the synthesis of tricetanidin, a natural pigment isolated from black tea, was accomplished.

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Mas, T. A New and Convenient One-Stepsynthesis of the Natural 3-DeoxyanthoCyanidins Apigeninidinand Luteolinidin Chlorides from 2,4,6-TriacetoxyBenzaldehyde. Synthesis 2003, 2003 , 1878– 1880, DOI: 10.1055/s-2003-40982

Al Bittar, S. ; Mora, N. ; Loonis, M. ; Dangles, O. A Simple Synthesis of 3-Deoxyanthocyanidins and Their O-Glucosides. Tetrahedron 2016, 72 , 4294– 4302, DOI: 10.1016/j.tet.2016.05.076

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A simple synthesis of 3-deoxyanthocyanidins and their O-glucosides

Al Bittar, Sheiraz; Mora, Nathalie; Loonis, Michele; Dangles, Olivier

Tetrahedron (2016), 72 (29), 4294-4302CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

This work deals with the chem. synthesis of simple analogs of anthocyanins, the main class of water-sol. natural pigments. Flavylium ions with hydroxyl, methoxyl and β-D-glucopyranosyloxyl substituents at positions 4' and 7 have been prepd. by straightforward chem. procedures. Moreover, the two 3-deoxyanthocyanidins of red sorghum apigeninidin (4',5,7-trihydroxyflavylium) and luteolinidin (3',4',5,7-tetrahydroxyflavylium) were synthesized in a one-step protocol. Attempts to synthesize luteolinidin O-β-D-glucosides resulted in a mixt. of the 5-O- and 7-O-regioisomers in low yield. A preliminary study of the 4'-β-D-glucopyranosyloxy-7-hydroxyflavylium and 7-β-D-glucopyranosyloxy-4'-hydroxy-flavylium ions shows that simply changing the glucosidation site can profoundly affect the color intensity and stability.

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Johnson, A. W. ; Melhuish, R. R. A New Synthesis of Benzopyrylium Salts. J. Chem. Soc. 1947, 346– 350, DOI: 10.1039/jr9470000346

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New synthesis of benzopyrylium salts

Johnson, A. W.; Melhuish, R. M.

Journal of the Chemical Society (1947), (), 346-50CODEN: JCSOA9; ISSN:0368-1769.

Benzopyrylium salts can be prepd. from phenols and CH≡CCOR in the presence of acid. BzC≡CH (I) (0.5 g.) and 0.5 g. 2-C10H7OH in 10 cc. AcOH, treated with HCl 1 hr. and the mixt. allowed to stand overnight, give 0.8 g. 2-phenyl-2-naphthopyrylium chloride, m. 133-4°; it also results with concd. H2SO4 or FeCl3 (100 g. FeCl3 in 150 cc. concd. HCl). MeC≡CH (0.25 g.) and 0.5 g. 2-C10H7OH with 3 cc. FeCl3 in 5 cc. AcOH give 2-methyl-2-naphthopyrylium ferrichloride, pale green, m. 141-3°. (m-Methoxyphenyl)ethynylcarbinol, pale yellow, b3 103°, is obtained from m-MeOC6H4CHO and HC≡CNa in liquid NH3; oxidation with CrO3 in dil. Me2CO and concd. H2SO4 in a N atm. at 10-15° gives m-methoxyphenyl ethynyl ketone (II), b1 92-3°, m. 15-16°. II (0.55 g.), 0.5 g. 2-C10H7OH, and 1 cc. concd. H2SO4 in 10 cc. AcOH, kept 2 days and the ppt. crystd. from dil. HCl, give 1.02 g. 2-(m-methoxyphenyl)-2-naphthopyrylium chloride (IIa, R = m-MeOC6H4), red, m. 124-5°; ferrichloride, orange, m. 178-9°; perchlorate, brown, m. 210-11°; FeCl3 or 70% HClO4 can be used as the catalyst. 2,3,4-(HO)3C6H2CHO (1.54 g.) and 1.2 g. PhAc with 5 cc. concd. H2SO4 in 20 cc. AcOH give 1.65 g. 7,8-dihydroxyflavylium chloride (III), KMnO4 color, m. 236-7° (decompn.); Na2CO3 gives a deep blue color in EtOH; perchlorate, dark reddish brown, m. 223-4°; III results in 0.5 g. yield from 0.3 g. 1,2,3-C6H3(OH)3 and 0.7 g. I; 1,3,5-C6H3(OH)3 gives the 5,7-isomer of III. m-C6H4(OH)2 and I with concd. H2SO4 in AcOH (4 days at room temp.) give 7-hydroxyflavylium chloride, m. above 260°; ferrichloride, orange-red, m. 166-7°; it causes sneezing and is stable in air; perchlorate, orange, m. 220-1°; similarly, m-MeOC6H4OH gives 7-methoxyflavylium chloride, deep orange, m. 96-7°; the dil. HCl soln. shows a bright green fluorescence; perchlorate, pale yellow, m. 222-3°, deep green fluorescence in AcOH. 2-Hydroxycarbazole (0.6 g.), 0.4 g. I, and 1 cc. concd. H2SO4 in 40 cc. AcOH, kept 2 days at room temp., the product pptd. with 100 cc. ether, and crystd. from 2500 cc. 3% HCl, give 0.7 g. 2-phenylcarbazolo[1',2',5,6]-pyrylium chloride (IV), dark brown, does not m. below 270°; ferrichloride, dark red, m. 235-6°; perchlorate, black with metallic luster, m. 267-8°. 6-Ethoxythioindoxyl (0.75 g.) and 0.5 g. I with 1 cc. concd. H2SO4 in 10 cc. AcOH, kept at room temp. overnight, give 2-phenyl-6'-ethoxythionaphtheno[2',3',5,6]pyrylium chloride, pale brown, amorphous, very susceptible to heat; ferrichloride, red, m. 170-1°; perchlorate, brown, m. 231-3°. No pyrylium salt has been isolated from I and PhOH, m-MeC6H4OH, p-MeC6H4SH, 1-phenyl-3-methyl-5-pyrazolone, N-propyloxindole, 1,3-dihydroxyisoquinoline, 1,3-diketohydrindene, or 7-chloro-3-keto-5-methyl-2,3-dihydro-1,4-benzothiazine. PhOH and I with FeCl3 react slowly to give a poor yield of flavylium ferrichloride (possibly because of simultaneous para substitution of PhOH); 0.4 g. p-MeC6H4OH and 0.5 g. I with 3 cc. FeCl3 in 5 cc. AcOH give 0.7 g. 6-methylflavylium ferrichloride, yellow, m. 171-2°; 0.5 g. p-MeOC6H4OH and 0.5 g. I with 1 cc. concd. H2SO4 in 10 cc. AcOH give 0.5 g. of 6-methoxyflavylium chloride and FeCl3 gives 1.1 g. of the ferrichloride. Thus I can be used with phenols other than "reactive" phenols.

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Kueny-Stotz, M. ; Isorez, G. ; Chassaing, S. ; Brouillard, R. Straightforward Synthesis of Highly Hydroxylated Phloroglucinol-Type 3-Deoxyanthocyanidins. Synlett 2007, 2007 , 1067– 1070, DOI: 10.1055/s-2007-977433

Sousa, A. ; Mateus, N. ; De Freitas, V. A Novel Reaction Mechanism for the Formation of Deoxyanthocyanidins. Tetrahedron Lett. 2012, 53 , 1300– 1303, DOI: 10.1016/j.tetlet.2012.01.006

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A novel reaction mechanism for the formation of deoxyanthocyanidins

Sousa, Andre; Mateus, Nuno; de Freitas, Victor

Tetrahedron Letters (2012), 53 (10), 1300-1303CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The synthesis of deoxyanthocyanidins from the reaction between cinnamic aldehydes (coniferaldehyde and sinapaldehyde) and phloroglucinol is reported herein. The resulting structures were characterized by visible, MS, and NMR spectroscopy.

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Sousa, C. ; Mateus, N. ; Perez-Alonso, J. ; Santos-Buelga, C. ; De Freitas, V. Preliminary Study of Oaklins, a New Class of Brick-Red Catechinpyrylium Pigments Resulting from the Reaction between Catechin and Wood Aldehydes. J. Agric. Food Chem. 2005, 53 , 9249– 9256, DOI: 10.1021/jf051970e

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Preliminary study of oaklins, a new class of brick-red catechinpyrylium pigments resulting from the reaction between catechin and wood aldehydes

Sousa, Carlos; Mateus, Nuno; Perez-Alonso, Joaquin; Santos-Buelga, Celestino; De Freitas, Victor

Journal of Agricultural and Food Chemistry (2005), 53 (23), 9249-9256CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Several structurally related pigments were found to result from the reaction between catechin and coniferaldehyde/sinapaldehyde extd. from oak wood. Their structures were tentatively identified by mass spectrometry, and their formation was studied in different pH and temp. conditions for several days. They were all found to have a characteristic catechinpyrylium core, thereby constituting a new class of compds. named as oaklins. One of the main oaklins was also detected in a com. table red wine aged in oak barrels.

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De Freitas, V. ; Sousa, C. ; Silva, A. M. S. ; Santos-Buelga, C. ; Mateus, N. Synthesis of a New Catechin-Pyrylium Derived Pigment. Tetrahedron Lett. 2004, 45 , 9349– 9352, DOI: 10.1016/j.tetlet.2004.10.132

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Synthesis of a new catechin-pyrylium derived pigment

de Freitas, Victor; Sousa, Carlos; Silva, Artur M. S.; Santos-Buelga, Celestino; Mateus, Nuno

Tetrahedron Letters (2004), 45 (51), 9349-9352CODEN: TELEAY; ISSN:0040-4039. (Elsevier B.V.)

A new catechin-pyrylium derived pigment compd. was synthesized from the reaction of catechin with sinapaldehyde in acidic conditions and its structure characterized by UV-vis, MS and NMR spectroscopy. Similar compds. could be expected to be formed in wines and contribute to changes in color and astringency during aging.

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Bianco, A. ; Cavarischia, C. ; Guiso, M. Total Synthesis of Anthocyanidins Via Heck Reaction. Nat. Prod. Res. 2006, 20 , 93– 97, DOI: 10.1080/14786410500059474

[Crossref], [PubMed], [CAS], Google Scholar

Total synthesis of anthocyanidins via Heck reaction

Bianco, Armandodoriano; Cavarischia, Claudia; Guiso, Marcella

Natural Product Research (2006), 20 (1), 93-97CODEN: NPRAAT; ISSN:1478-6419. (Taylor & Francis Ltd.)

Anthocyanidin moiety was obtained by cyclization of a 2-hydroxychalcone prepd. by the Heck approach to the synthesis of flavonoids. 1-(3,4-dimethoxyphenyl)-prop-2-en-1-one was used as a coupling partner along with o-acetoxyiodobenzene in the Heck reaction.

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Bianco, A. ; Cavarischia, C. ; Farina, A. ; Guiso, M. ; Marra, C. A New Synthesis of Flavonoids Via Heck Reaction. Tetrahedron Lett. 2003, 44 , 9107– 9109, DOI: 10.1016/j.tetlet.2003.10.060

[Crossref], [CAS], Google Scholar

A new synthesis of flavonoids via Heck reaction

Bianco, Armandodoriano; Cavarischia, Claudia; Farina, Angela; Guiso, Marcella; Marra, Carolina

Tetrahedron Letters (2003), 44 (51), 9107-9109CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science B.V.)

Several naturally occurring flavonoids have been synthesized following a new proposed method based on the use of the Heck reaction. The key step involves the coupling of an aryl vinyl ketone with an aryl iodide. This procedure affords the flavonoid moiety in a single step.

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Dekić, M. ; Kolašinac, R. ; Radulović, N. ; Šmit, B. ; Amić, D. ; Molčanov, K. ; Milenković, D. ; Marković, Z. Synthesis and Theoretical Investigation of Some New 4-Substituted Flavylium Salts. Food Chem. 2017, 229 , 688– 694, DOI: 10.1016/j.foodchem.2017.02.139

[Crossref], [PubMed], [CAS], Google Scholar

Synthesis and theoretical investigation of some new 4-substituted flavylium salts

Dekic, Milan; Kolasinac, Rejhana; Radulovic, Niko; Smit, Biljana; Amic, Dragan; Molcanov, Kresimir; Milenkovic, Dejan; Markovic, Zoran

Food Chemistry (2017), 229 (), 688-694CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Flavylium salts substituted at 4-position with hydroxyphenyl substituents were synthesized by acidic condensation according to a slightly modified procedure described by Robinson and Walker. Their thermodn. properties and conformational anal. have been studied at DFT level.

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Willstätter, R. ; Schmidt, O. T. Synthesis of New Anthocyanidins. Ber. Dtsch. Chem. Ges. B 1924, 57B , 1945– 1950, DOI: 10.1002/cber.19240571032

[Crossref], [CAS], Google Scholar

Synthesis of new anthocyanidins

Willstatter, Richard; Schmidt, Otto Th.

Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen (1924), 57B (), 1945-50CODEN: BDCBAD; ISSN:0365-9488.

Two new anthocyanidins have been synthesized by the method described in the preceding abstr. From 3,5,7-trimethoxycoumarin (I) and PhMgBr was obtained 2-phenyl-3,5,7-trihydroxybenzopyrylium chloride (II), and from I and 2,4-(MeO)2C6H3MgI 2-resorcyl- or 2-[2',4'-dihydroxyphenyl]-3,5,7-trihydroxybenzopyrylium chloride (III), which, owing to their relationship with the flavanol dyes galangin and morin are designated reap. galanginidin chloride (rather than galangidin; cf. Pratt and Robinson, C. A. 18, 985) and moridinin chloride, and the names galanginin and morinin are reserved for their as yet unknown glucosides. III, which is isomeric with cyanidin (IV), resembles pelargonidin (V) in its color phenomena much more than it does IV. II is no longer red but scarlet-yellow in H2O and orange in alc.; the beautiful color of the anthocyans therefore depends on the presence of at least one HO group in the Ph residue. II differs materially from the other anthocyanidins in lacking the blue (or violet) color of the alkali color salt; the violet AmOH soln. of the color base (oxonium betaine) shows with Na2CO3 or NaOH no change to blue and yields none of the substance to the alkali. The salt C20H21O6Cl, obtained in 0.8 g. yield from 0.9 g. I and the Grignard reagent from 3 g. 2,4-(MeO)2C6H3I, hair-like needles, bluish red by transmitted light under the microscope, loses H2O in a desiccator and in air reabsorbs an amt. corresponding to 4H2O, dissolves in 0.5% HCl with a yellowish deep red color, in alc. with a very similar color but a faint violet tinge, the color of the alc. soln. being stable for days even without the addn. of acids, but in H2O the color fades out and the turbid liq. deposits colorless flocks of the pseudo base, which in NaOH forms a stable lemon-yellow soln. regenerating the dye salt with acid; 0.4 g. heated 30 mins. at 135-40° with 1 g. PhOH and 15 cc. HI (d. 1.7) gives 0.25 g. of the brown-red iodide corresponding to III. III itself seps. from hot 7% HCl on rapid cooling in Fe(OH)3-like flocks changing in a few hrs. into red-brown needles contg. (air-dry) 1.5H2O, which, after drying, absorb 2H2O from the air; from an alc. HCl soln. treated with 10% aq. HCl and freed from most of the alc. by evapn. it seps. in light red-brown prisms apparently with 3H2O, while if the alc. is completely evapd. off the salt seps. in brown needles with violet tinge contg. 1H2O, which at 105° in a high vacuum lose 0.5 of the HCl and then absorb 1H2O from the air. III is very little sol. in hot 0.1% HCl, considerably in hot 1% HCl, easily (more so than IV and V) in hot 7% HCl and very easily in 0.5% alc. HCl. The soln. in 0.1% aq. HCl is peach-blossom red and with a much more bluish tinge, probably owing to hydrolysis, than in more concd. acids; in 1 and 7% HCl it is scarlet, much more yellowish and less blue than IV and therefore much more similar (in these solns. but not in 0.1% HCl) to V than to IV; on addn. of much alc. the soln. in 1% HCl becomes much more bluish red; in 7% HCl it behaves very much like V on addn. of much alc., the soln. being much less bluish than that in 1% HCl treated with alc.; in 0.5% alc. HCl it is bluish red like V; in 1% Na2CO3 it dissolves with violet-blue to blue-violet color and is extd. with the same color by Na2CO3, from the KMnO4-like soln. obtained by shaking the HCl soln. with AmOH and treating with NaOAc. The dil. soln. in alc. decolorized by heating 15 mins. regenerates only a small amt. of III on heating with HCl, showing that the pseudo base undergoes alteration to a greater degree and more easily than that of IV. With FeCl3 III gives no color reaction. I (1.5 g.) and the Grignard reagent from 3 g. PhBr yield 1.3 g. yellow-red prisms losing 13.3% H2O in the desiccator and becoming purple; they now have approx. the compn. of a di-HCl salt C18H18O4Cl2 (found, Cl 17.8%, MeO 21.7%, sol. in acids with intense red color and no blue tinge and becoming yellow-red on diln., gives with HI the red-brown iodide (sol. only in traces in hot H2O with light orange color, the soln. becoming milky on cooling owing to sepn. of the carbinol), corresponding to the bright red II, which is sol. in alc. with orange-red, in CHCl3 with raspberry-red color, the latter soln. becoming colorless with conversion of the II into the pseudo base. The deep red AmOH soln. shaken with Na2CO3 or NaOAc becomes violet, the soln., unlike those of IV and other anthocyanidins, yielding no dye to an excess of Na2CO3; likewise the HCl soln. added to an excess of Na2CO3, becomes colorless and on adding more alkali turns light yellow. The soln. in 0.5% alc. HCl has no blue tinge and is scarlet; in 1% aq. HCl it is scarlet-yellow. II forms various hydrates.

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Willstätter, R. ; Zechmeister, L. Syntheses of Pelargonidin. Sitzb. kgl. preuss. Akad. 1914, 886– 893

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Syntheses of pelargonidin

Willstatter, R.; Zechmeister, L.

(1914), (), 886-93 ISSN:.

through Chem. Zentr. 1914, II, 1359-60. After detg. the constitution of anthocyan (cf. C. A. 8, 3421-2) 2 ways were seen to be suitable for the synthesis of pelargonidin, the application of the Grignard reaction to coumarin, or the action of o-hydroxybenzaldehydes upon compds. containing the -CH2CO- group. By means of the 1st method, pelargonidin chloride was shown to have the formula Methoxyacetic anhydride, b20 124-8°. 5,7-Dimethyoxyacetyl-3-methoxycoumarin, (MeOCH2CO2)2C6H2.O.CO.C(OMe):CH, colorless less prisms, m. 170-1°, gives, by pptn. with acids from NaOH, 5,7-dihydroxy-3-methoxycoumarin (a), prisms and rhomboidal plates, m. 280-5° (decomp.). 3,5,7-Trimethoxycoumarin, from (a) by the action of CH2N2, prisms and long, rectangular plates, m. 171-2°, gives with p-MeOC6H4MgBr, pelargonidin tetramethyl ether chloride, purplish prisms.

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Roehri-Stoeckel, C. ; Gonzalez, E. ; Fougerousse, A. ; Brouillard, R. Synthetic Dyes: Simple and Original Ways to 4-Substituted Flavylium Salts and Their Corresponding Vitisin Derivatives. Can. J. Chem. 2001, 79 , 1173– 1178, DOI: 10.1139/v01-089

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Synthetic dyes: simple and original ways to 4-substituted flavylium salts and their corresponding vitisin derivatives

Roehri-Stoeckel, Christine; Gonzalez, Emmanuel; Fougerousse, Andre; Brouillard, Raymond

Canadian Journal of Chemistry (2001), 79 (7), 1173-1178CODEN: CJCHAG; ISSN:0008-4042. (National Research Council of Canada)

Flavylium salts substituted at the 4-position, e.g. I, have been prepd. according to a Grignard reaction of some flavones with appropriate alkyl- and aryl-magnesium bromides. Among these compds., 4-Me flavylium salts were gently reacted with arom. aldehydes, affording new anthocyanidin pigments, e.g. II, some of which are of the vitisin family. These are the first examples of chem. synthesized vitisidins (aglycons of vitisins). Compared to the more common flavylium salts, they demonstrate a large bathochromic shift (from about 100-200 nm), thus providing blue-violet and green colors, so difficult to obtain with anthocyanidins in general.

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Iacobucci, G. A. ; Sweeny, J. G. The Chemistry of Anthocyanins, Anthocyanidins and Related Flavylium Salts. Tetrahedron 1983, 39 , 3005– 3038, DOI: 10.1016/S0040-4020(01)91542-X

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The chemistry of anthocyanins, anthocyanidins and related flavylium salts

Iacobucci, Guillermo A.; Sweeny, James G.

Tetrahedron (1983), 39 (19), 3005-38CODEN: TETRAB; ISSN:0040-4020.

A review with 265 refs.

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Shibata, K. ; Shibata, Y. ; Kasiwagi, I. Studies on Anthocyanins: Color Variation in Anthocyanins. J. Am. Chem. Soc. 1919, 41 , 208– 220, DOI: 10.1021/ja01459a008

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Anthocyanins: color-variation in anthocyanins

Shibata, Keita; Shibata, Yuji; Kasiwagi, Itizo

Journal of the American Chemical Society (1919), 41 (), 208-20CODEN: JACSAT; ISSN:0002-7863.

Former investigators have invariably used metallic Zn or Mg and excess of inorganic acid to reduce the yellow plant pigments of the flavonol series and obtained red anthocyanin pigments, the oxonium salts of Willst.ovrddot.atter, but S., S. and K. have used organic acids. With monobasic acids they obtained, for the most part, deep green to bluish green pigments, depending on the reagent used, and have been able to isolate some of the pigments. Myricetin (I) with glacial AcOH and Mg gives compds. of the compn. C15H11O8MgOAc.nMg(OAc)2 (n = 2 or 4). They represent the reaction as consisting in the formation, by reduction, of a phenopyrylium compd. (II) which, by loss of AcOH, yields the organometallic compd. (III) and this adds 2 or 4 mols. of Mg(OAc)2 according to Werner's co.ovrddot.ordination theory. Similarly myricitrin gives a deep blue product co.ovrddot.ordinated with 4Mg(OAc)2. These blue or green pigments are sol. in H2O and alc. with the same color and form neutral solns. but with dil. acids the color changes to red with formation of the oxonium salt. Even with inorganic acids under certain conditions green or blue pigments are formed, myricetin with alc. HCl forming a deep green pigment (III, with MgCl instead of MgOAc); in this case MgCl2 does not add co.ovrddot.ordinately. On the basis of their work, S., S. and K. conclude that organo-metallic or complex compds. of reduced flavonol glucosides are the most important factor in the production of flower colors; that the "blue" anthocyanins are the complex compds. of reduced flavonol glucosides containing several HO groups of the flavonol nucleus besides those of sugar mols. and the metal with which they are co.ovrddot.ordinated is probably Ca or Mg; and that the "violet," "violet-red" and "red pigments" are either the analogous metallic complex compds. of flavonol glucosides containing fewer auxochrome HO groups or are a mixt. of the blue pigments and their products of decompn. by excess of acids, i. e., Willst.ovrddot.atter's red oxonium. salts. The theory proposed is confirmed by the fact that in alc. exts. of various flowers treated with salts of the alk. earths and heavy metals the color change is always bathochromatic, e. g., from red or violet-red to beautiful blue or violet. The reversible color change of the exts. of some petals produced by temp. changes is interpreted as due to the formation and decompn. of the complex compds. Tables are given, showing the color of the pigment produced by reduction of myricetin in alc., Me2CO and Et2O with Mg and formic, acetic, propionic, butyric, valeric, lactic, oxalic, citric, benzoic, m-nitrobenzoic, cinnamic, chloroacetic, trichloroacetic and camphoric acid, the colors produced by adding 1 drop of H2O or dil. HCl to the reduced Me2CO solns., the colors obtained by reduction of quercitin, quercitrin, rutin, kempferol, chrysin and toringin in alc., the colors obtained by reduction of myricetin with AcOH, ClCH2CO2H and CCl3CO2H and Zn in alc. and Et2O and with Al-Hg in alc., and finally with Mg, Fe and Zn and HCl, HBr, HNO3, H2SO4, H3PO4 and H3PO3; and finally the colors produced by adding salts of Ca, Sr, Ba, Mg, Zn, Al, Sn, Pb, Cr, NH4, Mn, Fe, Ni, Co, Cu and Hg and AcOH, HCl, NaOH and K2CO3 to alc. exts. of 24 flowers.

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Asahina, Y. ; Nakagome, G. ; Inubuse, M. Flavonoid Glycosides. V. Reduction of Flavone and Flavonone Derivatives. Ber. Dtsch. Chem. Ges. B 1929, 62B , 3016– 3021, DOI: 10.1002/cber.19290621112

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Flavanone glucosides. V. Reduction of flavone and favanone derivatives

Asahina, Yasuhiko; Nakagome, Goro; Inubuse, Mototaro

Berichte der Deutschen Chemischen Gesellschaft [Abteilung] B: Abhandlungen (1929), 62B (), 3016-21CODEN: BDCBAD; ISSN:0365-9488.

cf. C. A. 23, 3475. Apigenin, naringenin, sakuranetin and hesperitin can be reduced with Na-Hg to the corresponding benzopyrylium compds. The reaction has now been extended to acacctin (apigenin 4'-Me ether) (I), eriodictyol (3'4',5,7-tetra-hydroxyflavanone) (II) and homoriodictyol (3'-methoxy-4'5,7-trihydroxyflavanone) (III). Previously it has not been found possible to convert quercetin in alk. soln. into cyanidin, but from its penta-Me ether (IV) has now been obtained with Na-Hg the pseudo base of cyanidin penta-Me ether (V). The properties of the chloride do not agree wholly with those of Pratt and Robinson's synthetic product but its spectrum agrees with that of the cyanidin group. The glucosides, apiin, naringin, sakuranin and hesperidin, likewise gave on reduction in alk. soln. substances forming red to violet-red dyes on acidification, but on account of their easy soly. they could not be isolated in pure form. Acacetidin, C16H13O4Cl.H2O, from I, dark red, does not m. 300°, sol. in alc. with yellow-red color not changed by NaOAc or NH3, in N alkalies and in hot concd. Na2CO3 with red color; addn. of concd. alkali produces a turbid orange-yellow liquid which again becomes red on acidification. Luteolindin, C18H11O5Cl.H2O, from II, deep violet-red, does not m. 300°, sol. in alc. with violet-red color changed to blue by a drop of FeCl3, gives a violet color with aq. FeCl3, sol. in NaOH with blue, in Na2-CO3 with violet, in NaOAc with dirty brown color; yield, 18%. 3'-Me ether, from III, deep violet-red, m. 255° (decompn.), gives a red, color in alc. with a trace of FeCl3, sol, in alkalies and Na2CO3 with violet, in NaOAc with dirty brown color; yield, 21%. Pseudo base of V, light yellow powder m. around 60°, at once gives a red color in alc. with mineral acids or tartaric, citric or oxalic acid, forms in Et2O a red ppt. with FeCl3. Picrate, C26H23O18N2.O.5H2O, brown-red, m. 202-3°, easily sol. in alc, Me2CO and CHCl3 with cherry-red color. Chloride, C15H6OCl(OMe)5, dark violet-red, m. 158-9°, forms a red aq. soln. decolorized by NaOAc, KOH, alkali carbonates or NH4OH but again turned red by HCl, sol. in CHCl3 With violet-red color.

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King, H. G. C. ; White, T. 775. The Conversion of Flavonols into Anthocyanidins. J. Chem. Soc. 1957, 3901– 3903, DOI: 10.1039/jr9570003901

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Conversion of flavanols into anthocyanidins

King, H. G. C.; White, T.

Journal of the Chemical Society (1957), (), 3901-3CODEN: JCSOA9; ISSN:0368-1769.

Quercetin (1.0 g.) was refluxed 1 hr. with 1.0 g. Zn dust and 0.5 g. NaOAc in 20 ml. Ac2O, more Zn (1.0 g.) added and refluxing continued 1 hr., the mixt. filtered and poured into 250 ml. H2O to ppt. the compd. C25H22O12 (I), m. 80-100°. Reductive acetylation of quercetin pentaacetate, m. 193°, also gave I. Robinetin (1.0 g.) similarly gave 1.2 g. reduced acetate, m. 110°. Similarly, 0.2 g. fisetin gave 151 mg. C23H20O10 (II), m. 85-105°. Kaempherol (0.1 g.) gave 72 mg. reduced acetate (III), m. 92-100°. I (98.2 mg.) in 5:1 3N HCl-iso-PrOH was heated on a boiling H2O bath 40 min. and the mixt. evapd. to give 66.3 mg. cyanidin chloride (IV). Similarly, 58.4 mg. II gave 39.3 mg. fisetinidin chloride and 37.8 mg. III gave 29.3 mg. pelargonidin chloride. I (200 mg.) was kept overnight in 10 ml. 2% KOH in 50% aq. EtOH, the mixt. acidified, dild. with H2O, and extd. with EtOAc, then with iso-AmOH. The exts. were chromatographed on Solka-Floc to give IV.

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Elhabiri, M. ; Figueiredo, P. ; Fougerousse, A. ; Brouillard, R. A Convenient Method for Conversion of Flavonols into Anthocyanins. Tetrahedron Lett. 1995, 36 , 4611– 4614, DOI: 10.1016/0040-4039(95)00809-Q

[Crossref], [CAS], Google Scholar

A convenient method for conversion of flavonols into anthocyanins

Elhabiri, Mourad; Figueiredo, Paulo; Fourgerousse, Andre; Brouillard, Raymond

Tetrahedron Letters (1995), 36 (26), 4611-14CODEN: TELEAY; ISSN:0040-4039. (Elsevier)

Redn. of rutin I by zinc amalgam is 3% abs. methanolic hydrochloric acid provides pure 3-O-β-D-(6"-O-α-L-(6'''-deoxy-mannosyl))glucopyranosyl-cyanidin in good yield.

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Oyama, K.-i. ; Kimura, Y. ; Iuchi, S. ; Koga, N. ; Yoshida, K. ; Kondo, T. Conversion of Flavonol Glycoside to Anthocyanin: An Interpretation of the Oxidation–Reduction Relationship of Biosynthetic Flavonoid-Intermediates. RSC Adv. 2019, 9 , 31435– 31439, DOI: 10.1039/C9RA06986K

[Crossref], [CAS], Google Scholar

Conversion of flavonol glycoside to anthocyanin: an interpretation of the oxidation-reduction relationship of biosynthetic flavonoid-intermediates

Oyama, Kin-ichi; Kimura, Yuki; Iuchi, Satoru; Koga, Nobuaki; Yoshida, Kumi; Kondo, Tadao

RSC Advances (2019), 9 (54), 31435-31439CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)

An efficient conversion of rutin to the corresponding anthocyanin, cyanidin 3-O-rutinoside, was established. Clemmensen-type redn. of rutin gave a mixt. of flav-2-en-3-ol and two flav-3-en-3-ols, which were easily oxidized by air to give the anthocyanin. The interconversion reactions of these flavonoids provide insight into their biosynthetic pathway.

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Bjoroy, O. ; Rayyan, S. ; Fossen, T. ; Kalberg, K. ; Andersen, O. M. C-Glycosylanthocyanidins Synthesized from C-Glycosylflavones. Phytochemistry 2009, 70 , 278– 287, DOI: 10.1016/j.phytochem.2008.12.012

[Crossref], [PubMed], [CAS], Google Scholar

C-glycosylanthocyanidins synthesized from C-glycosylflavones

Bjoroy Orjan; Rayyan Saleh; Fossen Torgils; Kalberg Kjersti; Andersen Oyvind M

Phytochemistry (2009), 70 (2), 278-87 ISSN:0031-9422.

Nine C-glycosyldeoxyanthocyanidins, 6-C-beta-glucopyranosyl-7-O-methylapigeninidin, 6-C-beta-glucopyranosyl-7-O-methylluteolinidin, 6-C-beta-(2''-O-beta-glucopyranosylglucopyranosyl)-7-O-methylapigeninidin, 6-C-beta-(2''-O-beta-glucopyranosylglucopyranosyl)-7,4'-di-O-methylapigeninidin, 8-C-beta-glucopyranosylapigeninidin, 8-C-beta-(2''-O-alpha-rhamnopyranosylglucopyranosyl)apigeninidin, 8-C-beta-(2''-O-alpha-(4'''-O-acetylrhamnopyranosyl)glucopyranosyl)apigeninidin, 6,8-di-C-beta-glucopyranosylapigeninidin (8), 6,8-di-C-beta-glucopyranosyl-4'-O-methylluteolinidin (9), have been synthesized from their respective C-glycosylflavones (yields between 14% and 32%) by the Clemmensen reduction reaction using zinc-amalgam. The various precursors (C-glycosylflavones) of the C-glycosylanthocyanidins were isolated from either flowers of Iris sibirica L., leaves of Hawthorn 'Crataegi Folium Cum Flore', or lemons and oranges. This is the first time C-glycosylanthocyanidins have been synthesized. The structures of all flavonoids including the flavone rotamers were elucidated by 2D NMR techniques and high-resolution electrospray MS. The distribution of the various structural forms of 8 and 9 are different at pH 1.1, 4.5, and 7.0, however, the two pigments undergoes similar structural transformations at the various pH values. Pigments 8 and 9 with C-C linkages between the sugar moieties and the aglycone, were found to be far more stable towards acid hydrolysis than pelargonidin 3-O-glucoside, which has the typical anthocyanidin C-O linkage between the sugar and aglycone. This stability may extend the present use of anthocyanins as nutraceuticals, pharmaceuticals or colorants.

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Oyama, K. I. ; Kawaguchi, S. ; Yoshida, K. ; Kondo, T. Synthesis of Pelargonidin 3-O-6 ''-O-Acetyl-B-D-Glucopyranoside, an Acylated Anthocyanin, Via the Corresponding Kaempferol Glucoside. Tetrahedron Lett. 2007, 48 , 6005– 6009, DOI: 10.1016/j.tetlet.2007.06.134

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Synthesis of pelargonidin 3-O-6''-O-acetyl-β-D-glucopyranoside, an acylated anthocyanin, via the corresponding kaempferol glucoside

Oyama, Kin-Ichi; Kawaguchi, Satoshi; Yoshida, Kumi; Kondo, Tadao

Tetrahedron Letters (2007), 48 (34), 6005-6009CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The first total synthesis of pelargonidin 3-O-6''-O-acetyl-β-D-glucopyranoside, an acylated anthocyanin of magenta-colored Verbena flowers, was successfully carried out. The key intermediate, protected kaempferol 3-O-glucoside, was constructed by the Baker-Venkataraman rearrangement from a glucosyloxyacetophenone followed by Zn-Hg redn. to the corresponding acylated anthocyanin.

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Clark-Lewis, J. ; Skingle, D. Flavan Derivatives. Xviii. Synthesis of Hemiketals Containing the Peltogynol Ring System: 3(3′)-Hydroxyisochromano (4',3′:2, 3) Chromans. Conversion of 2'-Hydroxychdcones into Flav-3-Enes and Its Biosyntheticimplications. Aust. J. Chem. 1967, 20 , 2169– 2190, DOI: 10.1071/CH9672169c

[Crossref], [CAS], Google Scholar

Flavan derivatives. XVIII. Synthesis of hemiketals containing the peltogynol ring system. 3(3')-hydroxyisochromano[4',3':2,3]chromans. Conversion of 2'-hydroxychalcones into flav-3-enes and its biosynthetic implications

Clark-Lewis, John W.; Skingle, D. C.

Australian Journal of Chemistry (1967), 20 (10), 2169-90CODEN: AJCHAS; ISSN:0004-9425.

Redn. of 3 1'-oxoisochromeno[4',3':2,3]chromones (chromeno[3',2':3,4]isocoumarins) with LiAlH4 yielded 3(3')-hydroxyisochromano[4',3':1,3]chromans (hemiketals). The structures of these compds. (the 7-methoxy, 7,6',7'-trimethoxy, and parent hemiketals) were unequivocally established by N.M.R., mass spectral, and chem. data. The hemiketals contain the peltogynol (I) ring system, and one of them is the 7,6',7'-trimethyl ether of the structure originally proposed for this leucoanthocyanidin by Robinson and Robinson. The hemiketals were obtained as mixts. of cis- and trans-isomers which underwent equilibration in deuteriochloroform or in wet CHCl3, and configurations were assigned to the isomers from a detailed study of their N.M.R. spectra. The hemiketals suffered dehydration when heated further in deuteriochloroform, and gave the isochromeno[4',3':2,3]chromens (flav-2-enes), which immediately gave the flavylium salts with cold acids in air. The flavylium salts were also formed very readily from the hemiketals and acid, and the trimethoxyhemiketal gave the peltogynidin trimethyl ether cation. The mechanism of formation of the hemiketals from chromenoisocoumarins showed that 2'-hydroxychalocones are reduced by NaBH4 to flav-3-enes, and these readily give anthocyanidins when treated with acid. Parallel biol. redn. of chalcones is clearly possible and a plausible, new, biosynthetic pathway leading directly from 2'-hydroxychalcones to anthocyanidins and catechins is proposed. Flav-3-enes are valuable intermediates for prepn. of flavans, flavan derivs., and flavylium salts, and the new synthesis makes flav-3-enes readily accessible in one stage from 2'-hydroxychalcones. 37 references.

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Sweeny, J. G. ; Iacobucci, G. A. Synthesis of Anthocyanidins─Ii: The Synthesis of 3-Deoxyanthocyanidins from 5-Hydroxy-Flavanones. Tetrahedron 1977, 33 , 2927– 2932, DOI: 10.1016/0040-4020(77)88025-3

[Crossref], [CAS], Google Scholar

Synthesis of anthocyanidins. II. The synthesis of 3-deoxyanthocyanidins from 5-hydroxy-flavanones

Sweeny, J. G.; Iacobucci, G. A.

Tetrahedron (1977), 33 (22), 2927-32CODEN: TETRAB; ISSN:0040-4020.

Apigeninidin chloride (I; R = R1 = H) and 4'-O-methylluteolinidin chloride (I; R = OH, R1 = Me) were prepd. from naringenin (II; R = R1 = H) and hesperetin (II; R = OH, R1 = Me), resp., by sequential acetylation, NaBH4 redn., and benzoquinone oxidn.

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Sweeny, J. G. ; Iacobucci, G. A. Synthesis of Anthocyanidins─I: The Oxidative Generation of Flavylium Cations Using Benzoquinones. Tetrahedron 1977, 33 , 2923– 2926, DOI: 10.1016/0040-4020(77)88024-1

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Synthesis of anthocyanidins. I. The oxidative generation of flavylium cations using benzoquinones

Sweeny, J. G.; Iacobucci, G. A.

Tetrahedron (1977), 33 (22), 2923-6CODEN: TETRAB; ISSN:0040-4020.

The addn. of benzoquinone (I) or chloranil (II) enhanced the yields of 3-deoxyanthocyanidins formed on oxidn. of flavan-4-ols. E.g., oxidn. of 2,4-cis-hydroxy-3',4',5,7-tetramethoxyflavan with I and II and in the absence of oxidant in AcOH at 100° for 30 min gave 25, 66, and 3% tetramethylluteolinidin chloride (III), resp. Only slight improvements were noted when I and II were used in the oxidn. of flavan-3,4-diols.

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Mirza, R. ; Robinson, R. Conversion of Flavonols into Anthocyanidins. Nature 1950, 166 , 997– 997, DOI: 10.1038/166997b0

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Conversion of flavonols into anthocyanidins

Mirza, R.; Robinson, R.

Nature (London, United Kingdom) (1950), 166 (), 997CODEN: NATUAS; ISSN:0028-0836.

Qual. expts. show that 4-pyrones, flavonols, and xanthones are reduced by LiAlH4 to 4-pyranols, anthocyanidins, and xanthydrols, resp., yielding with acids salts which may be readily isolated, crystd., and identified. A paper chromatogram of the reduction product of kaempferol showed that the pelargonidin was uncontaminated by related pigments; pinacol-like coupling of the mols. is avoided.

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Jurd, L. Quinone Oxidation of Flavenes and Flavan-3,4-Diols. Chem. Ind. 1966, 40 , 1683– 1684

Waiss, A. C. ; Jurd, L. Synthesis of Flav-2-Enes and Flav-3-Enes. Chem. Ind. 1968, 23 , 743– 744

Kimura, Y. ; Oyama, K. ; Murata, Y. ; Wakamiya, A. ; Yoshida, K. Synthesis of 8-Aryl-O-Methylcyanidins and Their Usage for Dye-Sensitized Solar Cell Devices. Int. J. Mol. Sci. 2017, 18 , 427, DOI: 10.3390/ijms18020427

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Synthesis of 8-aryl-O-methylcyanidins and their usage for dye-sensitized solar cell devices

Kimura, Yuki; Oyama, Kin-ichi; Murata, Yasujiro; Wakamiya, Atsushi; Yoshida, Kumi

International Journal of Molecular Sciences (2017), 18 (2), 427/1-427/13CODEN: IJMCFK; ISSN:1422-0067. (MDPI AG)

Anthocyanins as natural pigments are colorful and environmentally compatible dyes for dye-sensitized solar cells (DSSCs). To increase the efficiency, we designed and synthesized unnatural O-methylflavonols and O-methylcyanidins that possess an aryl group at the 8-position. We synthesized per-O-methylquercetin from quercetin, then using selective demethylation prepd. various O-methylquercetins. Using the Suzuki-Miyaura coupling reaction, 8-arylation of per-O-methylquercetin was achieved. Using a LiAlH4 redn. or Clemmensen redn., these flavonols were transformed to the corresponding cyanidin derivs. in satisfactory yields. Using these dyes, we fabricated DSSCs, and their efficiency was investigated. The efficiency of tetra-O-methylflavonol was 0.31%. However, the introduction of the 8-aryl residue increased the efficiency to 1.04%. In comparison to these flavonols, O-methylcyanidins exhibited a lower efficiency of 0.05% to 0.52%. The introduction of the 8-aryl group into the cyanidin derivs. did not result in a remarkable increase in the efficiency. These phenomena may be due to the poor fit of the HOMO-LUMO level of the dyes to the TiO2 conduction band.

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Kimura, Y. ; Oyama, K. I. ; Kondo, T. ; Yoshida, K. Synthesis of 8-Aryl-3,5,7,3 ',4 '-Penta-O-Methylcyanidins from the Corresponding Quercetin Derivatives by Reduction with Lialh4. Tetrahedron Lett. 2017, 58 , 919– 922, DOI: 10.1016/j.tetlet.2017.01.065

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Synthesis of 8-aryl-3,5,7,3',4'-penta-O-methylcyanidins from the corresponding quercetin derivatives by reduction with LiAlH4

Kimura, Yuki; Oyama, Kin-ichi; Kondo, Tadao; Yoshida, Kumi

Tetrahedron Letters (2017), 58 (10), 919-922CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

Synthesis of 8-aryl-3,5,7,3',4'-penta-O-methylcyanidins, e.g., I·CF3CO2-, from the corresponding quercetin derivs. by redn. with LiAlH4 is reported. Regioselective iodination at the 8-position of penta-O-methylquercetin followed by a Suzuki-Miyaura reaction gave the 8-arylated quercetin derivs. By the redn. of 8-arylated quercetins using 4 equiv. of LiAlH4 at room temp. for 30 min, the corresponding anthocyanidins were obtained with a good yield.

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100

Kondo, T. ; Oyama, K. ; Nakamura, S. ; Yamakawa, D. ; Tokuno, K. ; Yoshida, K. Novel and Efficient Synthesis of Cyanidin 3-O-B-D-Glucoside from (+)-Catechin Via a Flav-3-En-3-Ol as a Key Intermediate. Org. Lett. 2006, 8 , 3609– 3612, DOI: 10.1021/ol0614976

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100

Novel and Efficient Synthesis of Cyanidin 3-O-β-D-Glucoside from (+)-Catechin via a Flav-3-en-3-ol as a Key Intermediate

Kondo, Tadao; Oyama, Kin-ichi; Nakamura, Saki; Yamakawa, Daisuke; Tokuno, Kazunari; Yoshida, Kumi

Organic Letters (2006), 8 (16), 3609-3612CODEN: ORLEF7; ISSN:1523-7060. (American Chemical Society)

A novel and efficient synthesis of cyanidin 3-O-β-D-glucoside (I) was accomplished the first time by a biomimetic oxidn. route. From (+)-catechin, 3-OH was glucosylated, and the 4-position of the nucleus was then oxidized and dehydrated to give the 5,7,3',4'-tetra-O-(tert-butyldimethylsilyl)flav-3-en-3-ol 3-O-glucoside as a key intermediate, which was deprotected and oxidized under air in hydrogen chloride-MeOH to give I.

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101

Cameira dos Santos, P. J. ; Brillouet, J. M. ; Cheynier, V. ; Moutounet, M. Detection and Partial Characterisation of New Anthocyanins Derived Pigments in Wine. J. Sci. Food Agric. 1996, 70 , 204– 208, DOI: 10.1002/(SICI)1097-0010(199602)70:2<204::AID-JSFA484>3.0.CO;2-F

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101

Detection and partial characterization of new anthocyanin-derived pigments in wine

Cameira-dos-Santos, Paulo-Jorge; Brillouet, Jean-Marc; Cheynier, Veronique; Moutounet, Michel

Journal of the Science of Food and Agriculture (1996), 70 (2), 204-8CODEN: JSFAAE; ISSN:0022-5142. (Wiley)

New anthocyanin-derived red-orange pigments were detected in wine in the course of cross-flow microfiltration expts. Anal. of the sugar and org. acid released resp. by acid and alk. hydrolysis showed that the two major products were a glucoside and the corresponding p-coumaroylglucoside. Mass spectrometry indicated mol. masses of 755·5 for the p-coumaroylglucoside and of 447·5 for its aglycon. Therefore, the new pigments are likely to result from condensation reaction between grape anthocyanins (possibly the 3-glucoside and 3-p-coumaroylglucoside of malvidin) and another wine component, which is not a flavanol. This reaction may participate in the mechanism of color change during ageing of red wines.

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102

Fulcrand, H. ; Cameira dos Santos, P. ; Sarni-Manchado, P. ; Cheynier, V. ; Favre-Bonvin, J. Structure of New Anthocyanin-Derived Wine Pigments. J. Chem. Soc., Perkin Trans. 1 1996, 735– 739, DOI: 10.1039/p19960000735

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102

Structure of new anthocyanin-derived wine pigments

Fulcrand, Helene; Cameira dos Santos, Paulo-Jorge; Sarni-Manchado, Pascale; Cheynier, Veronique; Favre-Bonvin, Jean

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1996), (7), 735-9CODEN: JCPRB4; ISSN:0300-922X. (Royal Society of Chemistry)

Two new malvidin-derived pigments, referred to as A and B, were detected in red wine made from Vitis vinifera grapes (var. Carignane) and characterized. The results reported herein indicate that they are formed by covalent binding of major wine anthocyanins [malvidin 3-monoglucoside and malvidin 3-(6-p-coumaroyl)monoglucoside] with 4-vinylphenol. Synthetic products obtained by reaction between these reagents were shown to be identical with the natural compds. on the basis of their UV-visible, mass and 1H NMR spectra. Their formation involves cyclization between C-4 and the hydroxy group at C-5 of the original flavylium moiety and the vinylphenol double bond. Subsequent oxidn. leads to pigment A or B. Their structure can yield two flavylium mesomeric forms, one corresponding to the malvidin type and the other to the pelargonidin type. The pigments' color suggests that the latter is the predominant form under our conditions.

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103

Bakker, J. ; Timberlake, C. F. Isolation, Identification, and Characterization of New Color-Stable Anthocyanins Occurring in Some Red Wines. J. Agric. Food Chem. 1997, 45 , 35– 43, DOI: 10.1021/jf960252c

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103

Isolation, Identification, and Characterization of New Color-Stable Anthocyanins Occurring in Some Red Wines

Bakker, Johanna; Timberlake, Colin F.

Journal of Agricultural and Food Chemistry (1997), 45 (1), 35-43CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Four new anthocyanin pigments were found in red wines in trace amts. and are thought to be formed in wines during maturation. Their structures were established by FAB-MS and NMR. Two pigments were identified as the 3-glucoside (vitisin A) and the 3-acetyl glucoside (acetylvitisin A) of malvidin contg. a C3H2O2 grouping, linking carbon 4 and the 5-hydroxy group of its mol. (vitisidin A). The other 2 anthocyanins were identified as the 3-glucoside (vitisin B) and the 3-acetyl glucoside (acetylvitisin B) of malvidin contg. a CH:CH moiety linking carbon 4 and the 5-hydroxy group of its mol. (vitisidin B or decarboxyvitisidin A). Unlike other anthocyanins, these novel compds. were wholly or partly resistant to bleaching by SO2 and express more color up to pH 7 than malvidin 3-glucoside. Detailed spectral measurements from 250 to 770 nm up to pH 7, including the use of CIELAB 76 measurements, indicate the formation of stable quinonoidal bases, confirming that there could be little formation of the colorless carbinol base forms.

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104

Fulcrand, H. ; Benabdeljalil, C. ; Rigaud, J. ; Cheynier, V. ; Moutounet, M. A New Class of Wine Pigments Generated by Reaction between Pyruvic Acid and Grape Anthocyanins. Phytochemistry 1998, 47 , 1401– 1407, DOI: 10.1016/S0031-9422(97)00772-3

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104

A new class of wine pigments generated by reaction between pyruvic acid and grape anthocyanins

Fulcrand, Helene; Benabdeljalil, Carime; Rigaud, Jacques; Cheynier, Veronique; Moutounet, Michel

Phytochemistry (1998), 47 (7), 1401-1407CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science Ltd.)

A new class of stable red pigments detected in grape pomace was analyzed by electro-spray ionization mass spectrometry. They were shown to be pyruvic acid derivs. of genuine grape anthocyanins by synthesis expts. The major product was identified by NMR (1H, NOE, HSQC, HMBC) expts. as the malvidin-3-mono-glucoside pyruvic acid adduct. Its formation results from cyclization between C-4 and the hydroxyl group at C-5 of the original flavylium moiety with the double bond of the enolic form of pyruvic acid, followed by dehydration and re-aromatization steps. This type of reaction leads to increased color stability. Various yeast metabolites other than pyruvic acid were shown to react with grape anthocyanins following this mechanism, suggesting that it may be an important route of conversion into stable pigments during the maturation and ageing of wine.

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105

Robertson, A. ; Whalley, W. B. ; Yates, J. The Pigments of Dragons Blood Resins.3. The Constitution of Dracorubin. J. Chem. Soc. 1950, 0 , 3117– 3123, DOI: 10.1039/JR9500003117

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105

Pigments of "dragon's blood" resins. III. The constitution of dracorubin

Robertson, Alexander; Whalley, W. B.; Yates, J.

Journal of the Chemical Society (1950), (), 3117-23CODEN: JCSOA9; ISSN:0368-1769.

cf. C.A. 45, 1126d. Dracorubin (I) (0.5 g.), 5 mL. 3 N aq. KOH, and 30 mL. MeOH at 0°, treated with 1 mL. 100-vol. H2O2, kept 3 days at 0°, and acidified with 2 N H2SO4, give (from 40 expts.) 2.5-3 g. draconol (II) and 0.8-1.3 g. dracoic acid (III), m. 167°, [α]25D -56.1° (CHCl3, c 1), violet-brown FeCl3 reaction in EtOH; Me ester (IV), m. 145°, [α]25D -80.5° (CHCl3, c 1), steel-blue FeCl3 reaction in EtOH; IV is unchanged on heating 20 h. at 145-50°; I (40 g.) also gives 8.5 g. BzOH and 0.5 g. BzOMe. III (0.7 g.) and 2 g. Cu bronze in 10 mL. quinoline, refluxed 15 min. in a N atm., give 0.5 g. 7-hydroxy-5-methoxyflavan (V), m. 95°, [α]25D -11.5° (MeOH, c 1); V results also on sublimation of III at a temp. above 180° (with or without Cu bronze) or by boiling 1 h. with 20% KOH. II yields a perchlorate, bright yellow, m. 206-8° (violent decompn.); the perchlorate of O-methyldraconol (VI), bright greenish yellow, m. 139-40° (vigorous decompn.); VI yields a boroacetic anhydride complex, C25H21O6B(OAc)2, bright lemon-yellow, m. 296° (decompn.). II (0.5 g.) in 100 mL. Me2CO, treated (4 h.) with 1 g. KMnO4 in 100 mL. Me2CO and kept 24 h., gives 50 mg. unchanged II and, after methylation, a trace of BzOMe, 20 mg. IV, and a trace of a compd. m. 124°. O-Diacetyldraconol (0.5 g.) in 15 mL. boiling AcOH, treated with 0.5 g. CrO3 (24 h.), gives 0.1 g. of a compd. C28H22O9, m. 250°. II and its ether contain a 4-pyrone system of the 1-hydroxyxanthone type. 1,3,5-C6H3(OH)3 (15 g.), 16.8 g. PhCH:CHCOCl, 17 g. AlCl3, and 50 mL. PhNO2 (24 h. at room temp.) give 5.6 g. 5,7-dihydroxyflavanone (VII), m. 199°; 10 g. VII, 4.8 mL. PhCH2Br, 10 g. K2CO3, and 200 mL. Me2CO, refluxed 2 h., give 14 g. 7-benzyloxy-5-hydroxy-flavanone (IX), m. 67°, intense red FeCl3 reaction in EtOH; 14.2 g. IX, 20 g. MeI, 20 g. K2CO3, and 600 mL. Me2CO, refluxed 15 h., give the 5-Me ether, m. 134-5°; debenzylation with Pd-C gives 7-hydroxy-5-methoxyflavanone (X), m. 225°. X (1 g.) in 40 mL. AcOH, reduced (24 h.) at room temp. with amalgamated Zn (10 g. Zn dust) and 5 mL. concd. HCl, gives 0.8 g. (±)-V; redn. of 0.5 g. X in AcOH with Pt oxide gives only 20 mg. (±)-V; redn. with Pd-C at 80-100° gives a nearly quant. yield of 6,2,4-MeO(HO)2C6H2COCH2CH2Ph, m. 192°. VII (1 g.), 1 g. K2CO3, and 0.4 g. MeI in 100 mL. Me2CO, refluxed 2 h., give the 7-Me ether, m. 100°; redn. with Zn and HCl in AcOH at room temp. gives 5-hydroxy-7-methoxyflavan, m. 148°; 5,7-dihydroxyflavan (XI), m. 196°. XI (1 g.), 10 g. KHCO3, and 125 g. C3H5(OH)3, heated 6 h. at 140° in a CO2 atm., give 0.7 g. 5,7-dihydro-6-flavancarboxylic acid, m. 178-9° (decompn.), intense blue-violet FeCl3 reaction in EtOH; Me ester, m. 109°; MeI-K2CO3 (6 h.) gives a quant. yield of Me 5,7-dimethoxy-6-flavancarboxylate, m. 95°. 6,2,4-Me(HO)2C6H2Ac (2 g.), 5 mL. HCN, and 1 g. Zn(CN)2 in 250 mL. ether, satd. with HCl, kept 24 h., and the product boiled with 250 mL. H2O, give 1.5 g. 3-formyl-2,4-dihydroxy-6-methoxyacetophenone (XII), m. 134°, red-brown FeCl3 reaction [2,4-dinitrophenylhydrazone, orange, m. 291-3° (decompn.)]; 1.5 g. XII in MeOH contg. 8 g. amalgamated Zn, mixed with 10 mL. concd. HCl and 5 mL. H2O and warmed 3-4 min., gives 0.9 g. 3,2,4,6-Me(HO)2(MeO)C6HAc (XIII), m. 222°. XIII (1 g.), 0.9 g. BzH, 10 mL. EtOH, and 16 mL. 60% aq. KOH, kept 24 h. at room temp., dild. with H2O, and acidified with 2 N HCl, give 0.5 g. 7-hydroxy-5-methoxy-8-methylflavanone (XIV), m. 213°; concn. of the mother liquor gives a small quantity of the corresponding chalcone, pale yellow, m. 213°, violet-brown FeCl3 reaction. Redn. of 0.35 g. XIV with 7 g. amalgamated Zn, 25 mL. AcOH, and 5 mL. concd. HCl (15 h.) gives 0.3 g. 7-hydroxy-5-methoxy-8-methylflavan (XV), m. 120°. V (1 g.) and 5 mL. HCN in 150 mL. ether, satd. with HCl and the residue (after 24 h.) hydrolyzed with H2O, give 0.7 g. of the 8-formyl deriv. (XVI), m. 128° [2,4-dinitrophenylhydrazone, crimson, m. 284° (decompn.)]; Clemmensen redn. gives XV. The acetate of XIV (m. 129) (1 g.), oxidized with KMnO4, gives 0.3 g. 7-hydroxy-5-methoxy-8-flavancarboxylic acid (XVII), m. 167°; Me ester, m. 130°, steel-blue FeCl3. reaction; MeI-K2CO3 gives Me 5,7-dimethoxy-8-flavancarboxylate, m. 88°. XVII (250 mg.) and 400 mg. brucine (4 H2O) in 2 mL. Me2CO and 15 mL. MeOH, give 100 mg. of the brucine salt, m. 134° (decompn.), [α]20D -46.3° (Me2CO, c 0.95), which yields (-)-XVII, identical with III. The brucine salt of natural III, with 2 mols. H2O, m. 134° (decompn.), [α]25D -53.6° (Me2CO, c 0.55). Alpinetin (Kimura, C.A. 34, 4063.5) is X. Since II and its Me ether are obtained from I and O-methyldracorbanuol, resp., by the loss of the elements of PhAc with the simultaneous formation of the CO and the 1-HO group of the xanthone residue, I has the following structure or the alternative structure in which the C-Me group is in the position marked * in the anhydro-2-phenylbenzopyranol residue.

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106

Fukui, Y. ; Kusumi, T. ; Masuda, K. ; Iwashita, T. ; Nomoto, K. Structure of Rosacyanin B, a Novel Pigment from the Petals of Rosa Hybrida. Tetrahedron Lett. 2002, 43 , 2637– 2639, DOI: 10.1016/S0040-4039(02)00305-2

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106

Structure of rosacyanin B, a novel pigment from the petals of Rosa hybrida

Fukui, Yuko; Kusumi, Takaaki; Masuda, Katsuyoshi; Iwashita, Takashi; Nomoto, Kyosuke

Tetrahedron Letters (2002), 43 (14), 2637-2639CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

A novel violet pigment, rosacyanin B, was isolated from the petals of Rosa hybrida cv. "M'me violet", and its structure was elucidated by spectroscopic methods. Rosacyanin B is the first C-4 substituted anthocyanidin isolated from intact plants.

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107

Andersen, O. M. ; Fossen, T. ; Torskangerpoll, K. ; Fossen, A. ; Hauge, U. Anthocyanin from Strawberry (Fragaria Ananassa) with the Novel Aglycone, 5-Carboxypyranopelargonidin. Phytochemistry 2004, 65 , 405– 410, DOI: 10.1016/j.phytochem.2003.10.014

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107

Anthocyanin from strawberry (Fragaria ananassa) with the novel aglycone, 5-carboxypyranopelargonidin

Andersen, Oyvind M.; Fossen, Torgils; Torskangerpoll, Kjell; Fossen, Arve; Hauge, Unni

Phytochemistry (Elsevier) (2004), 65 (4), 405-410CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science B.V.)

An anthocyanin, 1, with the novel 4-substituted aglycon, 5-carboxypyranopelargonidin, was isolated in small amts. from the acidified, methanolic ext. of strawberries, Fragaria ananassa Duch., by preparative HPLC after purifn. by partition against Et acetate, Amberlite XAD-7 and Sephadex LH-20 column chromatog. It was identified mainly by 2D NMR spectroscopy and electrospray LC-MS as the 3-O-β-glucopyranoside of 5-carboxy-2-(4-hydroxyphenyl)-3,8-dihydroxy-pyrano[4,3,2-de]-1-benzopyrylium, an anthocyanidin which is homologous to 5-carboxypyranomalvidin (vitisidin A) reported in red wines and 5-carboxypyranocyanidin recently isolated from red onions. By comparison of UV-Vis absorption spectra, 1 showed in contrast to 2, pelargonidin 3-O-β-glucopyranoside, a local absorption peak around 360 nm, a hypsochromic shift (8 nm) of the visible absorption max., and lack of a distinct UV absorption peak around 280 nm. The similarities between the absorption spectra of 1 in various acidic and neutral buffer solns. implied restricted formation of the instable colorless equil. forms, which are typical for most anthocyanins in weakly acidic solns. The molar absorptivity (ε) of 1 varied little with pH contrary to similar values of for instance the major anthocyanin in strawberry, 2. However, 2 revealed higher ε-values than 1 at all pH values except 5.1. At pH 5.1, the ε-value of 1 (6250) was nearly four times the corresponding value of 2 (1720), which showed the potential of 5-carboxypyranopelargonidin derivs. as colorants in solns. with pH around 5. The colors of 1 and 2 in buffered solns. with pH 1.1 and pH 6.9 have been described by the CIELAB coordinates hab (hue angle), C (chroma), and L (lightness).

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108

Lu, Y. R. ; Sun, Y. ; Foo, L. Y. Novel Pyranoanthocyanins from Black Currant Seed. Tetrahedron Lett. 2000, 41 , 5975– 5978, DOI: 10.1016/S0040-4039(00)00954-0

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108

Novel pyranoanthocyanins from black currant seed

Lu, Y.; Sun, Y.; Foo, L. Y.

Tetrahedron Letters (2000), 41 (31), 5975-5978CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

Four new pyranoanthocyanins, namely pyranocyanin A (I, R1=H, R2=rhamnose) and B I (R1=H, R2=H) and pyranodelphinin A I (R1=OH, R2=rhamnose) and B I (R1=OH, R2=H), with the pyrano[4,3,2-de]-1-benzopyrylium core structure were isolated together with known cyanidin 3-rutinoside and delphinidin 3-glucoside from black currant seed and their chem. structures were elucidated by means of 2D NMR and ES-MS.

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Rentzsch, W. ; Schwarz, M. ; Winterhalter, P. Pyranoanthocyanins - an Overview on Structures, Occurrence, and Pathways of Formation. Trends Food Sci. Technol. 2007, 18 , 526– 534, DOI: 10.1016/j.tifs.2007.04.014

[Crossref], [CAS], Google Scholar

109

Pyranoanthocyanins - an overview on structures, occurrence, and pathways of formation

Rentzsch, Michael; Schwarz, Michael; Winterhalter, Peter

Trends in Food Science & Technology (2007), 18 (10), 526-534CODEN: TFTEEH; ISSN:0924-2244. (Elsevier Ltd.)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVCitrzO&md5=52138471d058a227492e17616a639592

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He, J. ; Santos-Buelga, C. ; Silva, A. M. S. ; Mateus, N. ; De Freitas, V. Isolation and Structural Characterization of New Anthocyanin-Derived Yellow Pigments in Aged Red Wines. J. Agric. Food Chem. 2006, 54 , 9598– 9603, DOI: 10.1021/jf062325q

[ACS Full Text ], [CAS], Google Scholar

110

Isolation and Structural Characterization of New Anthocyanin-Derived Yellow Pigments in Aged Red Wines

He, Jingren; Santos-Buelga, Celestino; Silva, Artur M. S.; Mateus, Nuno; de Freitas, Victor

Journal of Agricultural and Food Chemistry (2006), 54 (25), 9598-9603CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Two newly formed yellow pigments that revealed unique spectral features were detected and isolated from an aged Port red wine by TSK Toyopearl HW-40(s) gel chromatog. and characterized by UV-visible spectrophotometry, 1H NMR and 13C NMR, and mass spectrometry (LC-ESI/MS). The UV-vis spectra of these pigments showed max. absorption at 478 nm that is significantly hypsochromically shifted from those of original grape anthocyanins and other pyranoanthocyanins, exhibiting a more yellow hue in acidic soln. The structures of these pigments correspond to methyl-linked pyranomalvidin 3-glucoside and its resp. coumaroyl glucoside deriv. They were shown to arise from the reaction between acetoacetic acid and genuine grape anthocyanins. Isolation and NMR identification using 1D and 2D NMR techniques are reported for the 1st time for this new family of anthocyanin-derived yellow pigments occurring in red wines.

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Hayasaka, Y. ; Asenstorfer, R. E. Screening for Potential Pigments Derived from Anthocyanins in Red Wine Using Nano-Electrospray Tandem Mass Spectrometry. J. Agric. Food Chem. 2002, 50 , 756– 761, DOI: 10.1021/jf010943v

[ACS Full Text ], [CAS], Google Scholar

111

Screening for Potential Pigments Derived from Anthocyanins in Red Wine Using Nano-electrospray Tandem Mass Spectrometry

Hayasaka, Yoji; Asenstorfer, Robert E.

Journal of Agricultural and Food Chemistry (2002), 50 (4), 756-761CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Red wine exts. were screened for potential wine pigments derived from anthocyanins, using a combination of nano-electrospray tandem mass spectrometry techniques. Fourteen aglycons were considered to be of anthocyanidin origin on the basis of their MS/MS spectra. The proposed structures of the aglycons were anthocyanidin C-4 substituted with vinyl linkage between C-4 and the hydroxy group at C-5. The anthocyanidin derivs. identified in the wine exts. were vinyl, vinylmethyl, vinylformic acid, 4-vinylphenol, 4-vinylguaiacol, and vinylcatechin adducts of malvidin as well as vinylformic acid and 4-vinylphenol adducts of peonidin and petunidin. The presence of vinyl alc., 4-vinylcatechol, and 4-vinylsyringol adducts of malvidin was also proposed.

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Schwarz, M. ; Wabnitz, T. C. ; Winterhalter, P. Pathway Leading to the Formation of Anthocyanin-Vinylphenol Adducts and Related Pigments in Red Wines. J. Agric. Food Chem. 2003, 51 , 3682– 3687, DOI: 10.1021/jf0340963

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112

Pathway Leading to the Formation of Anthocyanin-Vinylphenol Adducts and Related Pigments in Red Wines

Schwarz, Michael; Wabnitz, Tobias C.; Winterhalter, Peter

Journal of Agricultural and Food Chemistry (2003), 51 (12), 3682-3687CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

On the basis of observations from Vitis vinifera cv. Pinotage wines and expts. performed in model wine medium, a new chem. pathway responsible for the formation of anthocyanin-vinylphenol adducts in red wines is described. Until now, these pigments have been considered to be reaction products of anthocyanins and vinylphenols, the latter being generated during fermn. by enzymic decarboxylation of the resp. cinnamic acids. The mechanism of the novel pathway, involving intact hydroxycinnamic acid and anthocyanin, is explained. Only cinnamic acids with electron-donating substituents on the arom. ring, such as coumaric acid, ferulic acid, caffeic acid, and sinapic acid, undergo this conversion, as they stabilize an intermediately formed carbenium ion. Decarboxylation and oxidn. of the pyran moieties are the final steps in the generation of the corresponding 4-vinylphenol, 4-vinylguaiacol, 4-vinylcatechol, and 4-vinylsyringol adducts of anthocyanins in red wine.

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Schwarz, M. ; Winterhalter, P. A Novel Synthetic Route to Substituted Pyranoanthocyanins with Unique Colour Properties. Tetrahedron Lett. 2003, 44 , 7583– 7587, DOI: 10.1016/j.tetlet.2003.08.065

[Crossref], [CAS], Google Scholar

113

A novel synthetic route to substituted pyranoanthocyanins with unique color properties

Schwarz, Michael; Winterhalter, Peter

Tetrahedron Letters (2003), 44 (41), 7583-7587CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science B.V.)

Anthocyanins, isolated from natural sources by countercurrent chromatog., were reacted with cinnamic acids bearing at least one electron-donating substituent at the para-position. The resulting pyranoanthocyanins obtained by this simple one-step reaction were much less susceptible to pH shifts and retained their original color over a wide pH-range. Through reaction with p-dimethylamino cinnamic acid, synthetic malvidin- and cyanidin-based anthocyanins with a unique violet hue were prepd.

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Schwarz, M.; Winterhalter, P. 225th National Meeting of the American Chemical Society, New Orleans, LA, 2003; American Chemical Society, Washington, DC, 2003; p 179– 197.

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Mateus, N. ; Silva, A. M. S. ; Santos-Buelga, C. ; Rivas-Gonzalo, J. C. ; De Freitas, V. Identification of Anthocyanin-Flavanol Pigments in Red Wines by Nmr and Mass Spectrometry. J. Agric. Food Chem. 2002, 50 , 2110– 2116, DOI: 10.1021/jf0111561

[ACS Full Text ], [CAS], Google Scholar

115

Identification of Anthocyanin-Flavanol Pigments in Red Wines by NMR and Mass Spectrometry

Mateus, Nuno; Silva, Artur M. S.; Santos-Buelga, Celestino; Rivas-Gonzalo, Julian C.; de Freitas, Victor

Journal of Agricultural and Food Chemistry (2002), 50 (7), 2110-2116CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Three newly formed Port wine pigments were isolated by Toyopearl HW-40(s) gel chromatog. and semipreparative HPLC. Furthermore, the pigments were identified by mass spectrometry (LC/MS) and NMR techniques (1D and 2D). These anthocyanin-derived pigments showed UV-visible spectra different from those of the original grape anthocyanins. These pigments correspond to malvidin 3-glucoside linked through a vinyl bond to either (+)-catechin, (-)-epicatechin, or procyanidin dimer B3 [(+)-catechin-(+)-catechin]. NMR data of these pigments are reported for the 1st time.

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Francia-Aricha, E. M. ; Guerra, M. T. ; Rivas-Gonzalo, J. C. ; Santos-Buelga, C. New Anthocyanin Pigments Formed after Condensation with Flavanols. J. Agric. Food Chem. 1997, 45 , 2262– 2265, DOI: 10.1021/jf9609587

[ACS Full Text ], [CAS], Google Scholar

116

New Anthocyanin Pigments Formed after Condensation with Flavanols

Francia-Aricha, E.; Guerra, M. T.; Rivas-Gonzalo, J. C.; Santos-Buelga, C.

Journal of Agricultural and Food Chemistry (1997), 45 (6), 2262-2266CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The formation of 3 major pigments has been detected in model solns. imitating wine contg. malvidin-3-monoglucoside (Mv-3-glu) and procyanidin B2 in the presence of acetaldehyde. Two of them were reddish-blue compds. whose visible spectra are bathochromically shifted with regard to that of Mv-3-glu. They were assigned to 2 enantiomers contg. Mv-3-glu and B2 moieties linked across their C-8 by an Et bridge. A mol. ion at m/z 1097, consistent with such a structure, has been established by LC/MS for both of them. The 3rd majority pigment was an orange-red product possessing a spectrum with a max. wavelength in the visible region at 511 nm and a mol. ion at m/z 1093. A possible structure contg. 2 flavylium mesomeric forms, corresponding to malvidin and to pelargonidin, has been suggested for this compd. This pigment proved to be more stable than the 1st 2, as well as more resistant to discoloration by increased pH values and SO2. Similar pigments, whose spectra possess max. wavelengths in the visible region between 490 and 511 nm, have also been found in equiv. solns. contg. other flavan-3-ols [(+)-catechin, (-)-epicatechin, or procyanidin B3]. Evidence for the formation in red wine of pigments with similar spectral characteristics is also contributed.

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Rentzsch, M. ; Schwarz, M. ; Winterhalter, P. ; Hermosin-Gutierrez, I. Formation of Hydroxyphenyl-Pyranoanthocyanins in Grenache Wines: Precursor Levels and Evolution During Aging. J. Agric. Food Chem. 2007, 55 , 4883– 4888, DOI: 10.1021/jf0702491

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117

Formation of Hydroxyphenyl-pyranoanthocyanins in Grenache Wines: Precursor Levels and Evolution during Aging

Rentzsch, Michael; Schwarz, Michael; Winterhalter, Peter; Hermosin-Gutierrez, Isidro

Journal of Agricultural and Food Chemistry (2007), 55 (12), 4883-4888CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Grenache red wines were produced following 3 different winemaking techniques, i.e., small-scale std. exptl. wines and industrial-scale wines by both double-mash fermn. and fermn. in Ganimede vats. Wines were analyzed for their color properties, as well as the anthocyanin, flavonol, hydroxycinnamic acid, and pyranoanthocyanin profiles following alc. and malolactic fermn. The evolution of pyranoanthocyanins and their corresponding precursors in the exptl. wines was monitored at 6 and 10 mo of aging. Wines produced by double-mash fermn. exhibited superior color properties compared to Ganimede wines and the exptl. red wines, due to better extn. of flavonols and anthocyanins as well as a lower d.p. Pyranoanthocyanin formation varied within the different classes of pigments. Vitisins A and B were formed only during alc. fermn. Pinotin A (i.e., the reaction product from malvidin 3-glucoside and caffeic acid) formation took place only during the aging process, whereas formation of hydroxyphenyl-pyranoanthocyanins derived from p-coumaric and ferulic acid followed 2 different pathways, i.e., an enzymically assisted prodn. during fermn. and a pure chem. formation during aging.

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Hakansson, A. E. ; Pardon, K. ; Hayasaka, Y. ; de Sa, M. ; Herderich, M. Structures and Colour Properties of New Red Wine Pigments. Tetrahedron Lett. 2003, 44 , 4887– 4891, DOI: 10.1016/S0040-4039(03)01090-6

[Crossref], [CAS], Google Scholar

118

Structures and color properties of new red wine pigments

Hakansson, Anders E.; Pardon, Kevin; Hayasaka, Yoji; De Sa, Maria; Herderich, Markus

Tetrahedron Letters (2003), 44 (26), 4887-4891CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

Two new red pigments were synthesized by nucleophilic addn. of vinylphenols to malvidin 3-glucoside. The structures of the resulting pyranoanthocyanins were confirmed by electrospray-mass spectrometry and NMR spectroscopy (gHMQC, gHMBC and CIGAR expts.). By means of UV-vis spectroscopy the color properties of the pigments were characterized; it could be demonstrated that the pyranoanthocyanins retained their red color at pH 3.6 in model wine and were resistant to bisulfite-mediated bleaching. Finally, HPLC-MS anal. confirmed the presence of both anthocyanin-derived pigments in red wine.

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Schwarz, M. ; Jerz, G. ; Winterhalter, P. Isolation and Structure of Pinotin a, a New Anthocyanin Derivative from Pinotage Wine. Vitis 2003, 42 , 105– 106, DOI: 10.5073/vitis.2003.42.105-106

[Crossref], [CAS], Google Scholar

119

Isolation and structure of pinotin A, a new anthocyanin derivative from Pinotage wine

Schwarz, M.; Jerz, G.; Winterhalter, P.

Vitis (2003), 42 (2), 105-106CODEN: VITIAY; ISSN:0042-7500. (Institut fuer Rebenzuechtung Geilweilerhof)

Pinotin A, a malvidin-3-O-β-D-glucoside 4-vinylcatechol adduct from Pinotage (Pinot Noir ← Cinsault) wine, was isolated by high-speed countercurrent chromatog. (HSCCC) and semi-preparative HPLC and characterized by HPLC-ESI-MS and one-/two-dimensional NMR techniques.

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Cruz, L. ; Teixeira, N. ; Silva, A. M. S. ; Mateus, N. ; Borges, J. ; De Freitas, V. Role of Vinylcatechin in the Formation of Pyranomalvidin-3-Glucoside-(+)-Catechin. J. Agric. Food Chem. 2008, 56 , 10980– 10987, DOI: 10.1021/jf8021496

[ACS Full Text ], [CAS], Google Scholar

120

Role of Vinylcatechin in the Formation of Pyranomalvidin-3-glucoside-(+)-Catechin

Cruz, Luis; Teixeira, Natercia; Silva, Artur M. S.; Mateus, Nuno; Borges, Jose; de Freitas, Victor

Journal of Agricultural and Food Chemistry (2008), 56 (22), 10980-10987CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Reactions between malvidin-3-glucoside (mv3glc) and 8-vinylcatechin were carried out to synthesize pyranomv3glc-(+)-catechin pigment and to study the formation of intermediates. A rapid decrease of mv3glc content concomitant with the formation of more complex structures such as mv3glc-vinylcatechin [precursor of pyranomv3glc-(+)-catechin pigment] and mv3glc-divinylcatechin was obsd. On the other hand, 8-vinylcatechin undergoes acid-catalyzed dimerization in model wine soln., giving rise to 8-vinylcatechin dimers. These compds. were also found in the reaction between mv3glc and (+)-catechin mediated by acetaldehyde, which provides evidence for the formation of 8-vinylcatechin and its involvement in the formation of pyranoanthocyanins in aged red wines.

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Cruz, L. ; Borges, E. ; Silva, A. M. S. ; Mateus, N. ; De Freitas, V. Synthesis of a New (+)-Catechin-Derived Compound: 8-Vinylcatechin. Lett. Org. Chem. 2008, 5 , 530– 536, DOI: 10.2174/157017808785982211

[Crossref], [CAS], Google Scholar

121

Synthesis of a new (+)-catechin-derived compound: 8-vinylcatechin

Cruz, Luis; Borges, Enrique; Silva, Artur M. S.; Mateus, Nuno; de Freitas, Victor

Letters in Organic Chemistry (2008), 5 (7), 530-536CODEN: LOCEC7; ISSN:1570-1786. (Bentham Science Publishers Ltd.)

A strategy for the synthesis of 8-vinylcatechin I was developed, which involves (+)-catechin silylation with TBDMS-Cl, followed by bromination with NBS, a cross-coupling Suzuki reaction with vinylboronic acid pinacol ester and cleavage of TBDMS groups with TBAF, affording the 8-vinylcatechin.

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122

Es-Safi, N. E. ; Fulcrand, H. ; Cheynier, V. ; Moutounet, M. Studies on the Acetaldehyde-Induced Condensation of (−)-Epicatechin and Malvidin 3-O-Glucoside in a Model Solution System. J. Agric. Food Chem. 1999, 47 , 2096– 2102, DOI: 10.1021/jf9806309

[ACS Full Text ], [CAS], Google Scholar

122

Studies on the Acetaldehyde-Induced Condensation of (-)-Epicatechin and Malvidin 3-O-Glucoside in a Model Solution System

Es-Safi, Nour-Eddine; Fulcrand, Helene; Cheynier, Veronique; Moutounet, Michel

Journal of Agricultural and Food Chemistry (1999), 47 (5), 2096-2102CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The reaction between (-)-epicatechin, malvidin 3-O-glucoside, and acetaldehyde was studied in a model soln. system. Ethyl-linked flavanol oligomers and anthocyanin-flavanol derivs. were obsd., showing that the two polyphenols competed in the condensation process. Among the anthocyanin-ethyl-flavanol adducts, dimeric compds. in which the flavanol was linked to the anthocyanin with CH3-CH bridges were obsd. In addn., trimeric and tetrameric products contg. one anthocyanin and one, two, or three flavanols units were detected. A tetrameric product contg. two anthocyanin and two flavanol units was also found as a doubly charged ion. No compd. contg. more than two malvidin 3-O-glucosides was detected, suggesting that only one anthocyanin A ring summit can be included in the polymn. process, which thus stops when both ends are occupied by an anthocyanin moiety. Thioacidolysis of the two isolated anthocyanin-ethyl-flavanol dimeric derivs. showed that anthocyanin-Et linkage was not sensitive to such reactants, whereas the flavanol-Et one was. In addn., flavanol-Et linkages involved in anthocyanin-ethyl-flavanol adducts were found to be less sensitive to those involved in flavan-Et dimers.

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Bendz, G. ; Martensson, O. ; Nilsson, E. Studies of Flavylium Compounds. I. Some Flavylium Compounds and Their Properties. Ark. Kemi 1967, 27 , 67– 77

124

Oliveira, J. ; De Freitas, V. ; Mateus, N. A Novel Synthetic Pathway to Vitisin B Compounds. Tetrahedron Lett. 2009, 50 , 3933– 3935, DOI: 10.1016/j.tetlet.2009.04.072

[Crossref], [CAS], Google Scholar

124

A novel synthetic pathway to vitisin B compounds

Oliveira, Joana; de Freitas, Victor; Mateus, Nuno

Tetrahedron Letters (2009), 50 (27), 3933-3935CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The hemi-synthesis of vitisin B compds. I [R = H, COCH:CHC6H4-4-OH] was described for the first time through a new, simple and suitable cyclization reaction of malvidin-3-glucoside and malvidin-3-O-coumaroylglucoside with vinyloxy-trimethylsilane. The obtained compds. were identified by LC/DAD-MS and fully characterized by NMR anal. for the first time.

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He, J. R. ; Oliveira, J. ; Silva, A. M. S. ; Mateus, N. ; De Freitas, V. Oxovitisins: A New Class of Neutral Pyranone-Anthocyanin Derivatives in Red Wines. J. Agric. Food Chem. 2010, 58 , 8814– 8819, DOI: 10.1021/jf101408q

[ACS Full Text ], [CAS], Google Scholar

125

Oxovitisins: A new class of neutral pyranone-anthocyanin derivatives in red wines

He, Jingren; Oliveira, Joana; Silva, Artur M. S.; Mateus, Nuno; De Freitas, Victor

Journal of Agricultural and Food Chemistry (2010), 58 (15), 8814-8819CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A new class of stable yellowish pigments with similar unique spectral features, displaying only a pronounced broad band around 370 nm in the UV-vis spectrum, was detected in an aged Port wine fraction obtained by a combination of chromatog. on TSK Toyopearl HW-40(s) and Polyamide resins. These compds. were identified by liq. chromatog.-diode array detector/electrospray ionization mass spectrometry (LC-DAD/ESI/MS) and shown to be direct oxidative derivs. of carboxy-pyranoanthocyanins (vitisins A) by synthesis expts. performed in a wine model soln. Their structures were fully characterized by MS and NMR spectroscopy (1H, gCOSY, gHSQC, and gHMBC) and found to correspond to α-pyranone-anthocyanins (lactone or pyran-2-one-anthocyanins). Their formation involves first the nucleophilic attack of water into the pos. charged C-10 position of vitisins, followed by decarboxylation, oxidn., and dehydration steps, yielding a new and neutral pyranone structure. The occurrence of these novel pigments in aged wines points to a new pathway involving anthocyanin secondary products (vitisins A) as precursors of new pigments in subsequent stages of wine aging that may contribute to its color evolution.

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Mateus, N. ; Oliveira, J. ; Haettich-Motta, M. ; De Freitas, V. New Family of Bluish Pyranoanthocyanins. J. Biomed. Biotechnol. 2004, 2004 , 299– 305, DOI: 10.1155/S1110724304404033

[Crossref], [PubMed], [CAS], Google Scholar

126

New Family of Bluish Pyranoanthocyanins

Mateus Nuno; Oliveira Joana; Haettich-Motta Mafalda; de Freitas Victor

Journal of biomedicine & biotechnology (2004), 2004 (5), 299-305 ISSN:.

The use of anthocyanins has been investigated for the preparation of food and beverage natural colorants as they seem to have nontoxic effects. In this context, vinylpyranoanthocyanins were recently found to naturally occur in ageing red wine. This new family of anthocyanin-derived pigments may be obtained directly through the reaction between anthocyanin derivatives and other compounds. Some of these newly formed pigments have been found to exhibit a bluish color at acidic pH. The formation of bluish pigment was obtained through reaction between anthocyanin-pyruvic-acid adducts and flavanols in the presence of acetaldehyde. The formation of similar bluish pigments was attempted using other different precursors. The chromatic features of this kind of pigments bring promising expectations concerning the use of these naturally occurring blue pigments in the food industry.

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Mateus, N. ; Carvalho, E. ; Carvalho, A. R. F. ; Melo, A. ; Gonzalez-Paramas, A. M. ; Santos-Buelga, C. ; Silva, A. M. S. ; De Freitas, V. Isolation and Structural Characterization of New Acylated Anthocyanin-Vinyl-Flavanol Pigments Occurring in Aging Red Wines. J. Agric. Food Chem. 2003, 51 , 277– 282, DOI: 10.1021/jf020695i

[ACS Full Text ], [CAS], Google Scholar

127

Isolation and Structural Characterization of New Acylated Anthocyanin-Vinyl-Flavanol Pigments Occurring in Aging Red Wines

Mateus, Nuno; Carvalho, Elisabete; Carvalho, Alexandre R. F.; Melo, Andre; Gonzalez-Paramas, Ana M.; Santos-Buelga, Celestino; Silva, Artur M. S.; de Freitas, Victor

Journal of Agricultural and Food Chemistry (2003), 51 (1), 277-282CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Three newly formed pigments were detected and isolated from a 2-yr-old Port wine through TSK Toyopearl HW-40(S) gel column chromatog. and characterized by UV-visible spectrophotometry, NMR, and mass spectrometry (ESI/MS). 1H NMR and 13C NMR data for these pigments obtained using 1D and 2D NMR techniques (COSY, NOESY, gHSQC, and gHMBC) are reported for the 1st time. The structure of the pigments was found to correspond to the vinyl cycloadducts of malvidin 3-coumaroylglucoside bearing either a procyanidin dimer or a flavanol monomer ((+)-catechin or (-)-epicatechin). Addnl., conformational anal. was performed for one of these newly formed pigment using computer-assisted model building and mol. mechanics. A chem. nomenclature is proposed to unambiguously name this new family of anthocyanin-derived pigments.

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Mateus, N. ; Oliveira, J. ; Pissarra, J. ; Gonzalez-Paramas, A. M. ; Rivas-Gonzalo, J. C. ; Santos-Buelga, C. ; Silva, A. M. S. ; De Freitas, V. A New Vinylpyranoanthocyanin Pigment Occurring in Aged Red Wine. Food Chem. 2006, 97 , 689– 695, DOI: 10.1016/j.foodchem.2005.05.051

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128

A new vinylpyranoanthocyanin pigment occurring in aged red wine

Mateus, Nuno; Oliveira, Joana; Pissarra, Joao; Gonzalez-Paramas, Ana M.; Rivas-Gonzalo, Julian C.; Santos-Buelga, Celestino; Silva, Artur M. S.; De Freitas, Victor

Food Chemistry (2006), 97 (4), 689-695CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier B.V.)

A new pyranoanthocyanin-vinylphenol pigment was detected in an aged Port red wine. The UV-Vis spectrum of this pigment was found to have a λmax of 538 nm that is bathochromically shifted from that of original anthocyanins, exhibiting a more purple hue in acidic soln. This newly formed pigment was synthesized in model soln. through the reaction between malvidin 3-O-glucoside-pyruvic acid adduct and vinylphenol and its structure was assigned by NMR and mass spectrometry. This pigment is reported herein for the first time.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtValtbc%253D&md5=ffd620110faf4df2ed50428c23a8c173

129

Oliveira, J. ; De Freitas, V. ; Silva, A. M. S. ; Mateus, N. Reaction between Hydroxycinnamic Acids and Anthocyanin-Pyruvic Acid Adducts Yielding New Portisins. J. Agric. Food Chem. 2007, 55 , 6349– 6356, DOI: 10.1021/jf070968f

[ACS Full Text ], [CAS], Google Scholar

129

Reaction between Hydroxycinnamic Acids and Anthocyanin-Pyruvic Acid Adducts Yielding New Portisins

Oliveira, Joana; de Freitas, Victor; Silva, Artur M. S.; Mateus, Nuno

Journal of Agricultural and Food Chemistry (2007), 55 (15), 6349-6356CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Three new anthocyanin-derived pigments were found to occur in a 2-yr-old Port red wine. Their structures were elucidated through LC/DAD-MS and NMR anal. and were found to correspond to a pyranoanthocyanin moiety linked to substituted cinnamyl substituents. The structures of these compds. are very similar to the one already reported for portisins, with a phenolic moiety replacing the catechin moiety. The newly formed anthocyanin-derived compds. display a bathochromic shift of the λmax (∼540 nm) when compared with their anthocyanin-pyruvic acid adduct precursor (λmax = 511 nm), which may be due to the extended conjugation of the π electrons in the structures of those pigments. Studies performed in model solns. helped to clarify the formation mechanism of these pigments that can result from the nucleophilic attack of the olefinic double bond of a hydroxycinnamic acid to the electrophilic C-10 position of the anthocyanin-pyruvic acid adduct, followed by the loss of a formic acid mol. and decarboxylation. The chromatic characterization of these malvidin-3-glucoside-derived compds. revealed a higher resistance to discoloration against the nucleophilic attack by water and bisulfite when compared to malvidin-3-glucoside that is almost converted into its colorless hemiacetal form. However, the resistance to discoloration of these new pigments is not as high as the one reported for catechin-derived portisins. This could be explained by the presence of a smaller group (hydroxycinnamyl group), which does not protect so efficiently the chromophore against nucleophilic attack at the C-2 position. The occurrence of these pigments in red wine highlights new chem. pathways involving anthocyanin-pyruvic acid derivs. as precursors for the formation of new pigments in subsequent stages of wine aging that may contribute to its color evolution.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXntVyju7w%253D&md5=89b474ce14d15ff4308e9126870ed5c7

130

Mateus, N. ; Oliveira, J. ; Santos-Buelga, C. ; Silva, A. M. S. ; De Freitas, V. Nmr Structure Characterization of a New Vinylpyranoanthocyanin-Catechin Pigment (a Portisin). Tetrahedron Lett. 2004, 45 , 3455– 3457, DOI: 10.1016/j.tetlet.2004.03.007

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130

NMR structure characterization of a new vinylpyranoanthocyanin-catechin pigment (a portisin)

Mateus, Nuno; Oliveira, Joana; Santos-Buelga, Celestino; Silva, Artur M. S.; de Freitas, Victor

Tetrahedron Letters (2004), 45 (17), 3455-3457CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science B.V.)

A new polyphenolic compd., the structure of which corresponds to a pyranomalvidin-3-glucoside linked to a (+)-catechin unit through a vinyl linkage, has been characterized by UV-vis, MS and NMR spectroscopy. This compd. was obtained in an aq. alc. soln. from the reaction between a malvidin-3-glucoside-pyruvic acid deriv. and (+)-catechin in the presence of acetaldehyde.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXislOnsrg%253D&md5=8f5da8c16e36b6f274c9cc352bfa11c7

131

Oliveira, J. ; Azevedo, J. ; Silva, A. M. S. ; Teixeira, N. ; Cruz, L. ; Mateus, N. ; De Freitas, V. Pyranoanthocyanin Dimers: A New Family of Turquoise Blue Anthocyanin-Derived Pigments Found in Port Wine. J. Agric. Food Chem. 2010, 58 , 5154– 5159, DOI: 10.1021/jf9044414

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131

Pyranoanthocyanin Dimers: A New Family of Turquoise Blue Anthocyanin-Derived Pigments Found in Port Wine

Oliveira, Joana; Azevedo, Joana; Silva, Artur M. S.; Teixeira, Natercia; Cruz, Luis; Mateus, Nuno; de Freitas, Victor

Journal of Agricultural and Food Chemistry (2010), 58 (8), 5154-5159CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

In the present work, several compds. bearing similar spectroscopic features were found to occur in aged Port wines and resp. sediments (lees). The data obtained revealed two new families of compds. with unique spectroscopic characteristics, displaying a wavelength of the max. absorption at high wavelength in the visible spectrum at ∼730 and ∼680 nm. The structure of these pigments was elucidated by liq. chromatog./diode array detector-mass spectrometry (LC/DAD-MS) and NMR, and their formation pathway in wines was established. Their structure is constituted by two pyranoanthocyanin moieties linked together through a methane bridge. This new family of compds. displays an attractive and rare turquoise blue color at acidic conditions and has never been reported in the literature.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXisl2jsbg%253D&md5=6e222a8691ef79381410bf8fa06b24a8

132

Oliveira, J. ; Petrov, V. ; Parola, A. J. ; Pina, F. ; Azevedo, J. ; Teixeira, N. ; Bras, N. F. ; Fernandes, P. A. ; Mateus, N. ; Ramos, M. J. Chemical Behavior of Methylpyranomalvidin-3-O-Glucoside in Aqueous Solution Studied by Nmr and Uv-Visible Spectroscopy. J. Phys. Chem. B 2011, 115 , 1538– 1545, DOI: 10.1021/jp110593c

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132

Chemical Behavior of Methylpyranomalvidin-3-O-glucoside in Aqueous Solution Studied by NMR and UV-Visible Spectroscopy

Oliveira, Joana; Petrov, Vesselin; Parola, A. Jorge; Pina, Fernando; Azevedo, Joana; Teixeira, Natercia; Bras, Natercia F.; Fernandes, Pedro A.; Mateus, Nuno; Ramos, Maria Joao; de Freitas, Victor

Journal of Physical Chemistry B (2011), 115 (6), 1538-1545CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

In the present work, the proton-transfer reactions of the methylpyranomalvidin-3-O-glucoside pigment in water with different pH values was studied by NMR and UV-visible spectroscopies. The results showed four equil. forms: the methylpyranomalvidin-3-O-glucoside cation, the neutral quinoidal base, the resp. anionic quinoidal base, and a dianionic base unprotonated at the Me group. According to the NMR data, it seems that for methylpyranomalvidin-3-O-glucoside besides the acid-base equil. between the pyranoflavylium cation and the neutral quinoidal base, a new species is formed at pD 4.88-6.10. This is corroborated by the appearance of a new set of signals in the NMR spectrum that may be assigned to the formation of hemiketal/cis-chalcone species to a small extent. The two ionization consts. (pKa1 and pKa2) obtained by both methods (NMR and UV-visible) for methylpyranomalvidin-3-O-glucoside are in agreement (pKa1 = 5.17 ± 0.03; pKa2 = 8.85 ± 0.08; and pKa1 = 4.57 ± 0.07; pKa2 = 8.23 ± 0.04 obtained by NMR and UV-visible spectroscopies, resp.). Moreover, the fully dianionic unprotonated form (at the Me group) of the methylpyranomalvidin-3-O-glucoside is converted slowly into a new structure that displays a yellow color at basic pH. On the basis of the results obtained through LC-MS and NMR, the proposed structure was found to correspond to the flavonol syringetin-3-glucoside.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXoslymuw%253D%253D&md5=c268a5c3cb31286aa18c9e8843cd1741

133

Chassaing, S. ; Isorez, G. ; Kueny-Stotz, M. ; Brouillard, R. En Route to Color-Stable Pyranoflavylium Pigments─a Systematic Study of the Reaction between 5-Hydroxy-4-Methylflavylium Salts and Aldehydes. Tetrahedron Lett. 2008, 49 , 6999– 7004, DOI: 10.1016/j.tetlet.2008.09.139

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133

En route to color-stable pyranoflavylium pigments - a systematic study of the reaction between 5-hydroxy-4-methylflavylium salts and aldehydes

Chassaing, Stefan; Isorez, Geraldine; Kueny-Stotz, Marie; Brouillard, Raymond

Tetrahedron Letters (2008), 49 (49), 6999-7004CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The reaction of 5-hydroxy-4-methylflavylium salts with aldehydes, furnishing color-stable pyranoflavylium pigments, has been investigated in terms of scope and limitations. An unexpected chem. reactivity was obsd. and the origin of this reactivity is discussed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht12rsb3N&md5=8b4387ea281b3dfe0441a6130a05758e

134

Chassaing, S. ; Isorez-Mahler, G. ; Kueny-Stotz, M. ; Brouillard, R. Aged Red Wine Pigments as a Source of Inspiration for Organic Synthesis─the Cases of the Color-Stable Pyranoflavylium and Flavylium-(4→8)-Flavan Chromophores. Tetrahedron 2015, 71 , 3066– 3078, DOI: 10.1016/j.tet.2014.10.058

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134

Aged red wine pigments as a source of inspiration for organic synthesis-the cases of the color-stable pyranoflavylium and flavylium-(4→8)-flavan chromophores

Chassaing, Stefan; Isorez-Mahler, Geraldine; Kueny-Stotz, Marie; Brouillard, Raymond

Tetrahedron (2015), 71 (20), 3066-3078CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

Two flavylium-based chromophores peculiar to aged red wine pigments are investigated from a synthetic viewpoint. A condensation reaction between easy-to-prep. 5-hydroxy-4-(methyl)flavylium salts and aldehydes, providing color-stable pyranoflavylium pigments, further proves efficient and wide in scope. A set of some twenty structurally-related flavylium-based pigments has been prepd. and a structure-color relationship (mol. structure-property relationship) was discussed. Furthermore, the synthesis of the flavylium-(4→8)-flavan chromophore is achieved by a novel three-step sequence. The elaborated sequence starts with an iodine-magnesium exchange from an 8-(iodo)flavan, thus generating a magnesium-species that then smoothly reacts with a flavone to furnish an adduct, that finally leads to the expected chromophore by a dehydration reaction. The synthesis of the target compds. was achieved using (2R,3S)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-3,5,7-triol (catechin flavan) as a starting material, which was successfully converted into a Grignard reagent [(aryl)magnesium chloride deriv.]. The title compds. thus formed also included 8-hydroxy-5-(4-hydroxyphenyl)-2-(phenyl)pyrano[4,3,2-de]-1-benzopyrylium hexafluorophosphate and related substances.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFWis73K&md5=7d2eb10882585ba040692c92726a660d

135

da Silva, C. P. ; Pioli, R. M. ; Liu, L. ; Zheng, S. S. ; Zhang, M. J. ; Silva, G. T. D. ; Carneiro, V. M. T. ; Quina, F. H. Improved Synthesis of Analogues of Red Wine Pyranoanthocyanin Pigments. ACS Omega 2018, 3 , 954– 960, DOI: 10.1021/acsomega.7b01955

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135

Improved Synthesis of Analogues of Red Wine Pyranoanthocyanin Pigments

da Silva Cassio Pacheco; Pioli Renan Moraes; Liu Liu; Zheng Shasha; Zhang Mengjiao; Silva Gustavo Thalmer de Medeiros; Quina Frank H; Liu Liu; Zheng Shasha; Zhang Mengjiao; Carneiro Vania Maria Teixeira

ACS omega (2018), 3 (1), 954-960 ISSN:.

An improved procedure is described for the preparation of pyranoflavylium cations from the reaction of 5,7-dihydroxy-4-methylflavylium cation with aromatic aldehydes. Modifications of the procedure of Chassaing et al. (Tetrahedron Lett. 2008, 49, 6999-7004; Tetrahedron2015, 71, 3066-3078) circumvent the reported restriction to electron-rich benzaldehydes and provide access to a wide variety of substituted pyranoflavylium cations, including those with electron-withdrawing substituents or an attached heterocyclic or polycyclic aromatic ring. This opens the way for studies of substituent and structural effects on the ground and excited states of these pyranoanthocyanin analogues, the behavior of which should mirror fundamental aspects of the chemistry and photophysics of the pyranoanthocyanin chromophores present in mature red wines.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3MrisVOqsg%253D%253D&md5=0b9b38b7cd6636b51158db807ce153e9

136

Oliveira, J. ; Mateus, N. ; de Freitas, V. Synthesis of a New Bluish Pigment from the Reaction of a Methylpyranoanthocyanin with Sinapaldehyde. Tetrahedron Lett. 2011, 52 , 1996– 2000, DOI: 10.1016/j.tetlet.2011.02.079

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136

Synthesis of a new bluish pigment from the reaction of a methylpyranoanthocyanine with sinapaldehyde

Oliveira, Joana; Mateus, Nuno; de Freitas, Victor

Tetrahedron Letters (2011), 52 (16), 1996-2000CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The synthesis of a new pigment with a bluish color was obtained from the reaction of methylpyranomalvidin-3-glucoside with sinapaldehyde and its formation mechanism seems to involve a charge-transfer reaction pathway. The structure of this compd. was fully characterized by LC/DAD-MS and NMR. Its equil. forms present in water at different pH values and the resp. ionization consts. were detd. by UV-visible spectroscopy. The results revealed the presence of three equil. involving only deprotonation reactions at the 7-OH and 4'-OH positions of the pyranoanthocyanin moiety and at the 4'''-OH of the syringol moiety (pKa1 = 3.64 ± 0.01; pKa2 = 8.02 ± 0.01; pKa3 = 11.19 ± 0.01).

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjsFyksbg%253D&md5=5f961ca980b9ee1795f67b3fcdc318a8

137

Oliveira, J. ; Araújo, P. ; Fernandes, A. ; Mateus, N. ; de Freitas, V. Synthesis and Structural Characterization of Amino-Based Pyranoanthocyanins with Extended Electronic Delocalization. Synlett 2016, 27 , 2459– 2462, DOI: 10.1055/s-0035-1562471

[Crossref], [CAS], Google Scholar

137

Synthesis and Structural Characterization of Amino-Based Pyranoanthocyanins with Extended Electronic Delocalization

Oliveira, Joana; Araujo, Paula; Fernandes, Ana; Mateus, Nuno; de Freitas, Victor

Synlett (2016), 27 (17), 2459-2462CODEN: SYNLES; ISSN:0936-5214. (Georg Thieme Verlag)

Two new pyranoanthocyanin amino derivs. with extended electronic delocalization were obtained from the reaction of methylpyranomalvidin-3-O-glucoside with two amino-derived cinnamaldehydes, 4-(dimethylamino)- and 4-(diethylamino)-cinnamaldehyde. Structural characterization revealed the presence of a butadienylidene linkage connecting the pyranoanthocyanin and the cinnamyl moieties. The unexpected red color presented by the new mols. is due to the presence of a dicationic form of the pigments at acidic pH as confirmed by ESI-MS.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1egtL%252FO&md5=3ce64c1cc9a5b0b90d53befa38068308

138

Oliveira, J. ; Fernandes, A. ; de Freitas, V. Synthesis and Structural Characterization by Lc–Ms and Nmr of a New Semi-Natural Blue Amino-Based Pyranoanthocyanin Compound. Tetrahedron Lett. 2016, 57 , 1277– 1281, DOI: 10.1016/j.tetlet.2016.02.026

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138

Synthesis and structural characterization by LC-MS and NMR of a new semi-natural blue amino-based pyranoanthocyanin compound

Oliveira, Joana; Fernandes, Ana; de Freitas, Victor

Tetrahedron Letters (2016), 57 (11), 1277-1281CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The synthesis and structural characterization by LC-MS and NMR of a new blue amino-based pyranoanthocyanin-derived pigment is presented from the reaction of A-type vitisin and 4-(dimethylamino)-cinnamic acid. The structure of the new compd. is similar to portisin B being the hydroxyl and or methoxyl groups from the cinnamyl moiety substituted by a dimethylamino group. The presence of this amino group is responsible for the extensive π delocalization and by this, these new semi-natural pigments present an intense blue color.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XislyisLw%253D&md5=020e82ca7a35e10ced52fde71eb51d45

139

Cruz, L. ; Sousa, J. L. C. ; Marinho, A. ; Mateus, N. ; de Freitas, V. Synthesis and Structural Characterization of Novel Pyranoluteolinidin Dyes. Tetrahedron Lett. 2017, 58 , 159– 162, DOI: 10.1016/j.tetlet.2016.11.123

[Crossref], [CAS], Google Scholar

139

Synthesis and structural characterization of novel pyranoluteolinidin dyes

Cruz, Luis; Sousa, Joana L. C.; Marinho, Andreia; Mateus, Nuno; de Freitas, Victor

Tetrahedron Letters (2017), 58 (2), 159-162CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The synthesis and structural characterization by LC-MS and NMR of novel pyranoluteolinidin derivs. are reported. The compds. result from the reactions between luteolinidin and three different carboxylic acids in wine model-like solns. The three pigments possess different substituents attached to the D ring (Me, catechol and dimethylaminophenyl groups) and the same catechol group in the B ring, yielding a wide spectrum of colors from yellow to pink-purple.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVyjur3I&md5=482b7449394d680c58ca1b8eee3b1240

140

Sousa, J. L. C. ; Gomes, V. ; Mateus, N. ; Pina, F. ; de Freitas, V. ; Cruz, L. Synthesis and Equilibrium Multistate of New Pyrano-3-Deoxyanthocyanin-Type Pigments in Aqueous Solutions. Tetrahedron 2017, 73 , 6021– 6030, DOI: 10.1016/j.tet.2017.08.051

[Crossref], [CAS], Google Scholar

140

Synthesis and equilibrium multistate of new pyrano-3-deoxyanthocyanin-type pigments in aqueous solutions

Sousa, Joana L. C.; Gomes, Vania; Mateus, Nuno; Pina, Fernando; de Freitas, Victor; Cruz, Luis

Tetrahedron (2017), 73 (41), 6021-6030CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

Pyrano-flavylium compds. are flavylium derivs. with occurrence in processed foodstuffs such as wine and red fruit juices. In this work, the chem. equil. of "bio-inspired" pyrano-3-deoxyanthocyanin dyes (4-8), presenting different substituent groups in D ring (10-Me, 10-catechol, 10-dimethylaminophenyl, 10-carboxy) as well as in B ring (3',4'-dihydroxy, 4'-carboxy), were studied for the first time in aq. solns. by UV-Vis spectroscopy. The presence of a Me group at C-10 (pigment 4) seems to stabilize the flavylium cation (AH+) shifting the deprotonation of 7-OH to a higher pKa1 (pKa1 = 5.0 ± 0.1). On the other hand, the quinoidal bases (A, A-) were more stabilized for the pigments which undergo the first acid-base equil. at C-10 substituent, as could be obsd. by the pKa2 consts. (pKa2 = 8.4 ± 0.1 and pKa2 = 8.1 ± 0.1, pigments 6 and 8, resp.).

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVKqt73L&md5=00a696e67fb7c155ec88f8c62460e8cb

141

Vallverdú-Queralt, A. ; Meudec, E. ; Eder, M. ; Lamuela-Raventos, R. M. ; Sommerer, N. ; Cheynier, V. The Hidden Face of Wine Polyphenol Polymerization Highlighted by High-Resolution Mass Spectrometry. ChemistryOpen 2017, 6 , 336– 339, DOI: 10.1002/open.201700044

[Crossref], [PubMed], [CAS], Google Scholar

141

The Hidden Face of Wine Polyphenol Polymerization Highlighted by High-Resolution Mass Spectrometry

Vallverdu-Queralt, Anna; Meudec, Emmanuelle; Eder, Matthias; Lamuela-Raventos, Rosa M.; Sommerer, Nicolas; Cheynier, Veronique

ChemistryOpen (2017), 6 (3), 336-339CODEN: CHOPCK; ISSN:2191-1363. (Wiley-VCH Verlag GmbH & Co. KGaA)

Polyphenols, including tannins and red anthocyanin pigments, are responsible for the color, taste, and beneficial health properties of plant-derived foods and beverages, esp. in red wines. Known compds. represent only the emerged part of the "wine polyphenol iceberg". It is believed that the immersed part results from complex cascades of reactions involving grape polyphenols and yeast metabolites. We used a non-targeted strategy based on high-resoln. mass spectrometry and Kendrick mass defect plots to explore this hypothesis. Reactions of acetaldehyde, epicatechin, and malvidin-3-O-glucoside, representing yeast metabolites, tannins, and anthocyanins, resp., were selected for a proof-of-concept expt. A series of compds. including expected and so-far-unknown structures were detected. Random polymn. involving both the original substrates and intermediate products resulting from cascade reactions was demonstrated.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXnvVCltbw%253D&md5=ce0b0c9875032c2b283d3f7588a94b41

142

Vidal, S. ; Meudec, E. ; Cheynier, V. ; Skouroumounis, G. ; Hayasaka, Y. Mass Spectrometric Evidence for the Existence of Oligomeric Anthocyanins in Grape Skins. J. Agric. Food Chem. 2004, 52 , 7144– 7151, DOI: 10.1021/jf048939h

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142

Mass Spectrometric Evidence for the Existence of Oligomeric Anthocyanins in Grape Skins

Vidal, Stephane; Meudec, Emmanuelle; Cheynier, Veronique; Skouroumounis, George; Hayasaka, Yoji

Journal of Agricultural and Food Chemistry (2004), 52 (23), 7144-7151CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The fractionation of a grape skin ext. by multilayer countercurrent chromatog. coupled with step gradient elution allowed the prepn. of a fraction almost devoid of free anthocyanins. This fraction appeared to be almost exclusively polymeric, as judged by LC-MS anal., color-bleaching tests with SO2, and thiolysis. Electrospray mass spectrometric anal. indicated that the pigmented material in this fraction was chiefly composed of direct condensation products of anthocyanin extending up to trimers. With regard to their linkages, the anthocyanin units in the oligomers were possibly linked by either an A-type (by both carbon-carbon and ether bonds) or B-type (by carbon-carbon bond) linkage, like proanthocyanidins. The terminal anthocyanin unit of the oligomers is consistently in the flavylium form but the extension units are in the flavan form for the A-type oligomers and in the flavin form for the B-type oligomers. Although their linkages still need to be defined rigorously, this is the 1st mass spectrometric evidence confirming the existence of anthocyanin oligomers in the grape skin ext.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXosVOrsrw%253D&md5=03747b6ab87ae5b1152d2bf9907cd7f7

143

Alcalde-Eon, C. ; Escribano-Bailon, M. T. ; Santos-Buelga, C. ; Rivas-Gonzalo, J. C. Identification of Dimeric Anthocyanins and New Oligomeric Pigments in Red Wine by Means of Hplc-Dad-Esi/Msn. J. Mass Spectrom. 2007, 42 , 735– 748, DOI: 10.1002/jms.1208

[Crossref], [PubMed], [CAS], Google Scholar

143

Identification of dimeric anthocyanins and new oligomeric pigments in red wine by means of HPLC-DAD-ESI/MSn

Alcalde-Eon, Cristina; Escribano-Bailon, Maria Teresa; Santos-Buelga, Celestino; Rivas-Gonzalo, Julian C.

Journal of Mass Spectrometry (2007), 42 (6), 735-748CODEN: JMSPFJ; ISSN:1076-5174. (John Wiley & Sons Ltd.)

HPLC-diode array detector-electrospray ionization/ion trap mass spectrometry (HPLC-DAD-ESI/MSn) analyses carried out in red wine fractions revealed the existence of dimeric anthocyanins (A-A+), previously detected in grape skin, and allowed the detection and identification, for the 1st time, of other derived oligomers. The structure of these compds. was characterized according to their MSn (n = 1-4) fragmentation patterns. The newly detected oligomers consisted of a flavanol, (epi)catechin or (epi)gallocatechin, linked through its C4 position to the nucleophilic positions of the upper unit of a dimeric anthocyanin (F-A-A+). All the compds. contained malvidin as one of the anthocyanin subunits, whereas the other anthocyanin moiety could be either delphinidin, cyanidin, petunidin, peonidin or malvidin. With the fractionation method employed, the dimeric anthocyanins eluted in the same fractions as the monomeric anthocyanins. However, the new F-A-A+ oligomers were found in the same fractions as F-A+ dimers, which might indicate a structural similarity between both types of compds. ESI/MSn analyses, coupled or not to HPLC, showed to be a useful and powerful tool for detecting and identifying these oligomers in wines, which usually elute from reversed-phase columns as humps and/or are overlapped by the peaks of other compds. The detection of these oligomeric pigments in wine has provided more information about the complex pigments responsible for the elevation of the base line obsd. in the chromatograms of wines and has also revealed that oligomeric anthocyanins can take part in the reactions usually undergone by monomeric anthocyanins.

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144

Pati, S. ; Liberatore, M. T. ; Gambacorta, G. ; Antonacci, D. ; La Notte, E. Rapid Screening for Anthocyanins and Anthocyanin Dimers in Crude Grape Extracts by High Performance Liquid Chromatography Coupled with Diode Array Detection and Tandem Mass Spectrometry. J. Chromatogr. A 2009, 1216 , 3864– 3868, DOI: 10.1016/j.chroma.2009.02.068

[Crossref], [PubMed], [CAS], Google Scholar

144

Rapid screening for anthocyanins and anthocyanin dimers in crude grape extracts by high performance liquid chromatography coupled with diode array detection and tandem mass spectrometry

Pati, Sandra; Liberatore, Maria Teresa; Gambacorta, Giuseppe; Antonacci, Donato; La Notte, Ennio

Journal of Chromatography A (2009), 1216 (18), 3864-3868CODEN: JCRAEY; ISSN:0021-9673. (Elsevier B.V.)

A rapid and efficient method using high performance liq. chromatog. coupled with diode array detection and tandem mass spectrometry (HPLC-DAD-MS/MS) for fast screening large nos. of anthocyanins and anthocyanin dimers in different grape skin exts., without further sample clean-up procedures, was developed. A good sepn. of most detected anthocyanins was achieved in a run time of 15 min. Identification of anthocyanin pigments required a combination of several information: UV-vis spectra, MS and MS/MS spectra, and elution pattern. Many compds. have been here detected for the first time and their structures tentatively elucidated.

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145

Salas, E. ; Duenas, M. ; Schwarz, M. ; Winterhalter, P. ; Cheynier, W. ; Fulcrand, H. Characterization of Pigments from Different High Speed Countercurrent Chromatography Wine Fractions. J. Agric. Food Chem. 2005, 53 , 4536– 4546, DOI: 10.1021/jf0478096

[ACS Full Text ], [CAS], Google Scholar

145

Characterization of Pigments from Different High Speed Countercurrent Chromatography Wine Fractions

Salas, Erika; Duenas, Montserrat; Schwarz, Michael; Winterhalter, Peter; Cheynier, Veronique; Fulcrand, Helene

Journal of Agricultural and Food Chemistry (2005), 53 (11), 4536-4546CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A red wine, made from Cabernet Sauvignon (60%) and Tannat (40%) cultivars, was fractionated by high speed countercurrent chromatog. (HSCCC). The biphasic solvent system consisting of tert-Bu Me ether/n-butanol/acetonitrile/water (2/2/1/5, acidified with 0.1% trifluoroacetic acid) was chosen for its demonstrated efficiency in sepg. anthocyanins. The different native and derived anthocyanins were identified on the basis of their UV-visible spectra, their elution time on reversed-phase HPLC, and their mass spectra, before and after thiolysis. The HSCCC method allowed the sepn. of different families of anthocyanin-derived pigments that were eluted in different fractions according to their structures. The hydrosol. fraction was almost devoid of native anthocyanins. Further characterization (glucose quantification, UV-visible absorbance measurements) indicated that it contained flavanol and anthocyanin copolymers in which parts of the anthocyanin units were in colorless forms. Pigments in the hydrosol. fraction showed increased resistance to sulfite bleaching and to the nucleophilic attack of water.

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146

Oliveira, J. ; Bras, N. F. ; da Silva, M. A. ; Mateus, N. ; Parola, A. J. ; de Freitas, V. Grape Anthocyanin Oligomerization: A Putative Mechanism for Red Color Stabilization?. Phytochemistry 2014, 105 , 178– 185, DOI: 10.1016/j.phytochem.2014.05.006

[Crossref], [PubMed], [CAS], Google Scholar

146

Grape anthocyanin oligomerization: A putative mechanism for red color stabilization?

Oliveira, Joana; Bras, Natercia F.; da Silva, Mara Alhinho; Mateus, Nuno; Parola, A. Jorge; de Freitas, Victor

Phytochemistry (Elsevier) (2014), 105 (), 178-185CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Ltd.)

The equil. forms of malvidin-3-O-glucoside trimer present in grape skins were studied in aq. soln. at different pH values through UV-Visible spectroscopy. It was obsd. that the reactivity of this compd. is strongly dominated by acid-base chem. (pKa1 = 3.61±0.03; pKa2 = 6.83±0.06), with the reaction sequence hydration-tautomerization-isomerization accounting less than 10% of the overall reactivity. The decrease of hydration of this flavylium cation deriv. when compared to the original anthocyanins results from the formation of a cluster of the pigment with a high-energy of solvation that inhibits the access of water mols. to the flavylium cation core preventing by this way the hydration reactions. Overall of these results raise the hypothesis that polymn. may be a natural stabilization mechanism for the red color of anthocyanins.

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147

Remy, S. ; Fulcrand, H. ; Labarbe, B. ; Cheynier, V. ; Moutounet, M. First Confirmation in Red Wine of Products Resulting from Direct Anthocyanin-Tannin Reactions. J. Sci. Food Agric. 2000, 80 , 745– 751, DOI: 10.1002/(SICI)1097-0010(20000501)80:6<745::AID-JSFA611>3.0.CO;2-4

[Crossref], [PubMed], [CAS], Google Scholar

147

First confirmation in red wine of products resulting from direct anthocyanin-tannin reactions

Remy, Sophie; Fulcrand, Helene; Labarbe, Benoit; Cheynier, Veronique; Moutounet, Michel

Journal of the Science of Food and Agriculture (2000), 80 (6), 745-751CODEN: JSFAAE; ISSN:0022-5142. (John Wiley & Sons Ltd.)

Anal. of wine fractions before and after thiolysis confirmed the occurrence in red wine of direct reactions between anthocyanins and tannins established earlier in model solns. Results showed the presence of two types of structures differing in the linkage position of the anthocyanin moiety. Detection of malvidin-3-glucoside (Mv3g) among thiolysis products revealed the presence of anthocyanin-derived pigments in which Mv3g is linked by its C-6 or C-8 top. LC/MS anal. allowed the detection of two derivs. tentatively identified as flavenes or bicyclic condensation products yielded by the reaction of a flavanol monomer (C-6 or C-8 top) with malvidin-3-glucoside (C-4 position). The presence of the corresponding benzylthioethers after thiolysis of the polymeric fractions confirmed that procyanidins are similarly involved in the latter reaction. Besides, MS also allowed the detection of new benzylthioethers of catechin derivs. released after thiolysis of the wine fractions, indicating that in addn. to the postulated processes other types of reactions take place in wines.

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148

Hayasaka, Y. ; Kennedy, J. A. Mass Spectrometric Evidence for the Formation of Pigmented Polymers in Red Wine. Aust. J. Grape Wine Res. 2003, 9 , 210– 220, DOI: 10.1111/j.1755-0238.2003.tb00272.x

[Crossref], [CAS], Google Scholar

148

Mass spectrometric evidence for the formation of pigmented polymers in red wine

Hayasaka, Yoji; Kennedy, James A.

Australian Journal of Grape and Wine Research (2003), 9 (3), 210-220CODEN: AJGRFF; ISSN:1322-7130. (Australian Society of Viticulture and Oenology)

The polymeric materials (wine tannin) were isolated from a three-year-old Pinot Noir using Toyopearl TSK HW 40-F size exclusion chromatog. The wine tannin was analyzed by reversed-phase and gel permeation high performance liq. chromatog., UV-Vis spectrophotometry and mass spectrometry. Anal. by gel permeation chromatog. indicated that the isolate was in large part polymeric, and also indicated the presence of pigmented material monitored at a wavelength of 520 nm. Acid-catalysis in the presence of phloroglucinol indicated that the wine tannin contained 45% wt./wt. known proanthocyanidin material. The wine tannins gave a complicated mass spectrum featuring a large no. of intense signals derived from proanthocyanidins and, to a much lesser extent, a series of ions corresponding to masses consistent with direct condensation products of an anthocyanin with proanthocyanidins. The degree of polymn. by mass spectrometry was detected to be as high as an octamer composed of an anthocyanin combined with a proanthocyanidin heptamer. Based upon current evidence, the anthocyanin was proposed to be bound from the C-6/8 or C-4 positions of the anthocyanin to the resp. electrophilic or nucleophilic center of the proanthocyanidins. Only the species with the C-6/8 position of the anthocyanin linked with the proanthocyanidins seemed to be pigmented. Under acid-catalyzed conditions, an increase in malvidin-3-glucoside was obsd., suggesting that the non-pigmented form is possibly converted to the pigmented flavylium form. This is the first mass spectrometric evidence confirming the existence of pigmented polymers with an extension to octamers in wine.

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149

Salas, E. ; Atanasova, V. ; Poncet-Legrand, C. ; Meudec, E. ; Mazauric, J. P. ; Cheynier, V. Demonstration of the Occurrence of Flavanol-Anthocyanin Adducts in Wine and in Model Solutions. Anal. Chim. Acta 2004, 513 , 325– 332, DOI: 10.1016/j.aca.2003.11.084

[Crossref], [CAS], Google Scholar

149

Demonstration of the occurrence of flavanol-anthocyanin adducts in wine and in model solutions

Salas, E.; Atanasova, V.; Poncet-Legrand, C.; Meudec, E.; Mazauric, J. P.; Cheynier, V.

Analytica Chimica Acta (2004), 513 (1), 325-332CODEN: ACACAM; ISSN:0003-2670. (Elsevier Science B.V.)

Flavanol-anthocyanin (F-A+) adducts were detected in red wine. A mechanism involving acid-catalyzed cleavage of flavanol oligomers followed by nucleophilic addn. of the anthocyanin moiety (in its hemiketal form) to the resulting carbocation (F+) was postulated. To confirm this mechanism, reactions between malvidin 3-O-glucoside (Mv3glc) and procyanidin dimer epicatechin-(4-8)-epicatechin 3-O-gallate (B2-3'OG) were studied in a model soln. system at pH 2. A new pigment with a UV-Vis spectrum similar to that of Mv3glc and a signal at m/z=781 in the pos. ion mode was detected and was attributed to Ec-Mv3glc, in agreement with the proposed reaction pathway. A protocol adapted from the synthesis of procyanidin dimers, in which the terminal flavanol units was replaced with Mv3glc, was tested. Two new pigments were formed with a signal at m/z=781, in the pos. ion mode. These ions were attributed to catechin-Mv3glc. Both adducts obtained by hemisynthesis showed exactly the same fragmentation pattern as that present in wine. In particular, the loss of a 126 amu fragment corresponding to the unsubstituted A-ring of the flavanol unit indicated that all of them were (epi)catechin-Mv3glc adducts. These results prove that reactions between the carbocations resulting from cleavage of tannin interflavanic bonds and anthocyanins occur in wine.

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150

Cruz, L. ; Mateus, N. ; De Freitas, V. Identification by Mass Spectrometry of New Compounds Arising from the Reactions Involving Malvidin-3-Glucoside-(O)-Catechin, Catechin and Malvidin-3-Glucoside. Rapid Commun. Mass Spectrom. 2012, 26 , 2123– 2130, DOI: 10.1002/rcm.6330

[Crossref], [PubMed], [CAS], Google Scholar

150

Identification by mass spectrometry of new compounds arising from the reactions involving malvidin-3-glucoside-(O)-catechin, catechin and malvidin-3-glucoside

Cruz, Luis; Mateus, Nuno; de Freitas, Victor

Rapid Communications in Mass Spectrometry (2012), 26 (18), 2123-2130CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)

A study was made of the reactions that could occur in red wines between malvidin-3-glucoside-(O)-catechin (mv3glc-(O)-cat) adduct and catechin (cat) or malvidin-3-glucoside (mv3glc) in the presence of acetaldehyde. METHODS: Mv3glc-(O)-cat adduct (1 mM) was incubated with catechin (or mv3glc) in the presence of acetaldehyde (molar ratio of 1:4:10) in 12% ethanol/water at pH 3.2, protected from light and placed in an oven at 30°. The formation of the new compds. was monitored by liq. chromatog.-diode-array detection/electrospray ionization mass spectrometry (LC-DAD/ESI-MS) anal. in the pos. and neg. ion mode. RESULTS: The LC-DAD/ESI-MS characterization allowed the confirmation of the structures of the methylmethine-linked cat-mv3glc-(O)-cat ([M-H]- m/z 1097) and mv3glc-mv3glc-(O)-cat ([M]+ m/z 1301) adducts. CONCLUSIONS: The studies performed in model solns. showed that the colorless mv3glc-(O)-cat adduct can undergo some of the characteristic reactions of anthocyanins and flavan-3-ols that occur in red wine in the presence of acetaldehyde forming new methylmethine-bridged compds. Copyright © 2012 John Wiley & Sons, Ltd.

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151

Timberlake, C. F. ; Bridle, P. Interactions between Anthocyanins, Phenolic Compounds and Acetaldehyde and Their Significance in Red Wines. Am. J. Enol. Vitic. 1976, 27 , 97– 105

[CAS], Google Scholar

151

Interactions between anthocyanins, phenolic compounds, and acetaldehyde and their significance in red wines

Timberlake, C. F.; Bridle, P.

American Journal of Enology and Viticulture (1976), 27 (3), 97-105CODEN: AJEVAC; ISSN:0002-9254.

The interactions between anthocyanins (malvidin 3-glucoside [7228-78-6], malvidin 3,5-diglucoside [16727-30-3], and malvidin 3-p-coumarylglucoside-5-glucoside [61520-75-0]), phenolic compds. ((-)-epicatechin [490-46-0], procyanidin dimer B2 [29106-49-8], and procyanidin trimer (Cl [37064-30-5]), and acetaldehyde [75-07-0] were studied under conditions of light and darkness at pH 3.5. Reactions between the anthocyanins and phenolic compds. occurred very slowly and eventually resulted in xanthylium salts. Procyanidins B2 and C1 were partly transformed to epicatechin and polymeric procyanidins in the sunlight. The only reaction between anthocyanidins and acetaldehyde was in the case of malvidin 3-glucoside, which slowly polymerized. The addn. of acetaldehyde to mixts. of anthocyanins and phenolic compds., however, resulted in rapid and spectacular color augmentation. Spectral and Rf data are given for a new anthocyanin formed in the reaction of malvidin 3,5-diglucoside, acetaldehyde, and (+)-catechin.

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152

Rivas-Gonzalo, J. C. ; Bravo-Haro, S. ; Santos-Buelga, C. Detection of Compounds Formed through the Reaction of Malvidin-3-Monoglucoside and Catechin in the Presence of Acetaldehyde. J. Agric. Food Chem. 1995, 43 , 1444– 1449, DOI: 10.1021/jf00054a006

[ACS Full Text ], [CAS], Google Scholar

152

Detection of Compounds Formed through the Reaction of Malvidin 3-Monoglucoside and Catechin in the Presence of Acetaldehyde

Rivas-Gonzalo, Julian C.; Bravo-Haro, Santiago; Santos-Buelga, Celestino

Journal of Agricultural and Food Chemistry (1995), 43 (6), 1444-9CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The interaction between catechin and malvidin-3-monoglucoside in the presence of acetaldehyde was studied in model solns. The initial formation of two pigments (I and II), which later evolved to more condensed structures, was obsd. Evidence was found that for these pigments to be formed, catechin should first react with acetaldehyde and the resulting adduct later condenses with anthocyanin; it is proposed that pigments I and II are two enantiomeric structures of the catechin-(8→)-acetyl-(→8)-anthocyanin dimer. For their formation, a relatively acidic pH is necessary; this is attributed to the requirement that acetaldehyde be in the cationic form for condensation to occur. Condensation among catechin units involving acetaldehyde was also seen. Minor amts. of substances from the degrdn. of anthocyanin were detected, indicating that in the presence of acetaldehyde it is basically condensation and not degrdn. of the anthocyanin that occurs.

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153

Dallas, C. ; Ricardo-da-Silva, J. M. ; Laureano, O. Products Formed in Model Wine Solutions Involving Anthocyanins, Procyanidin B-2, and Acetaldehyde. J. Agric. Food Chem. 1996, 44 , 2402– 2407, DOI: 10.1021/jf940433j

[ACS Full Text ], [CAS], Google Scholar

153

Products Formed in Model Wine Solutions Involving Anthocyanins, Procyanidin B2, and Acetaldehyde

Dallas, Constantin; Ricardo-da-Silva, Jorge M.; Laureano, Olga

Journal of Agricultural and Food Chemistry (1996), 44 (8), 2402-2407CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Interaction between anthocyanins (3-glucosides of cyanidin, peonidin and malvidin), procyanidin B2 (B2), and acetaldehyde and the formation of new colored compds. was studied in model wine solns. The anthocyanins-procyanidin B2 condensation reaction showed first-order kinetics with or without the presence of acetaldehyde, and the reaction rates were calcd. In all the model solns. contg. anthocyanins, procyanidin B2, and acetaldehyde, rapid color augmentation with shifts toward violet were obsd. Two principal new compds. (thought to be trimers, linked at different positions) were detectable by HPLC, and their spectral properties were studied by diode-array spectroscopy. Malvidin-3-glucoside reacts more slowly than cyanidin-3-glucoside and peonidin-3-glucoside. Similar color changes were obsd. in model solns. contg. anthocyanins alone with acetaldehyde. Finally, we obsd. that the degrdn. const. rates for each anthocyanin increased in the following order: anthocyanins alone < anthocyanins + B2 < anthocyanins + acetaldehyde < anthocyanins + B2 + acetaldehyde. Similar increasing order of the reaction rates of procyanidin B2 was obsd. In both cases, the presence of acetaldehyde was of major importance in accelerating the chem. transformation of phenolic compds., inducing the formation of new products.

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154

Escribano-Bailón, T. ; Dangles, O. ; Brouillard, R. Coupling Reactions between Flavylium Ions and Catechin. Phytochemistry 1996, 41 , 1583– 1592, DOI: 10.1016/0031-9422(95)00811-X

[Crossref], [CAS], Google Scholar

154

Coupling reactions between flavylium ions and catechin

Escribano-Bailon, Teresa; Dangles, Olivier; Brouillard, Raymond

Phytochemistry (1996), 41 (6), 1583-92CODEN: PYTCAS; ISSN:0031-9422. (Elsevier)

In order to model natural polymeric pigments present in old red wines, new covalent adducts have been synthesized upon condensation of synthetic flavylium ions (models of anthocyanins) with catechin (model of tannins) in the presence and in the absence of acetaldehyde. These new pigments have been investigated by 1D and 2D NMR, HPLC, FAB-mass and UV-visible spectroscopies and mol. modeling. The two flavylium salts used in this work (3,4'-dimethoxy-7-hydroxyflavylium chloride and 5,7-dihydroxy-3,4'-dimethoxyflavylium chloride) display quite different reactivities toward catechin. The electronic donating effect of the catechin moiety and the formation of noncovalent dimers in acidic aq. or methanolic soln. should be mainly responsible for the improved stability of the flavylium chromophore in the new pigments.

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155

Lee, D. F. ; Swinny, E. E. ; Jones, G. P. Nmr Identification of Ethyl-Linked Anthocyanin-Flavanol Pigments Formed in Model Wine Ferments. Tetrahedron Lett. 2004, 45 , 1671– 1674, DOI: 10.1016/j.tetlet.2003.12.110

[Crossref], [CAS], Google Scholar

155

NMR identification of ethyl-linked anthocyanin-flavanol pigments formed in model wine ferments

Lee, David F.; Swinny, Ewald E.; Jones, Graham P.

Tetrahedron Letters (2004), 45 (8), 1671-1674CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science B.V.)

The ethyl-linked pigments produced by the reaction between either catechin or epicatechin and malvidin 3-O-glucoside with added acetaldehyde were been isolated and characterized by NMR spectroscopy. These pigments are generated in high concns. in model fermns. contg. added malvidin 3-O-glucoside and (epi)catechin when inoculated with Saccharomyces cerevisiae yeast. Thus, these pigments are produced during fermn. from metabolically produced acetaldehyde and provides evidence that the formation of these pigments may be a significant contributor to the purple coloration of young red wines.

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156

Sousa, C. ; Mateus, N. ; Silva, A. M. S. ; Gonzalez-Paramas, A. M. ; Santos-Buelga, C. ; De Freitas, V. Structural and Chromatic Characterization of a New Malvidin 3-Glucoside-Vanillyl-Catechin Pigment. Food Chem. 2007, 102 , 1344– 1351, DOI: 10.1016/j.foodchem.2006.04.050

[Crossref], [CAS], Google Scholar

156

Structural and chromatic characterization of a new Malvidin 3-glucoside-vanillyl-catechin pigment

Sousa, Carlos; Mateus, Nuno; Silva, Artur M. S.; Gonzalez-Paramas, Ana M.; Santos-Buelga, Celestino; de Freitas, Victor

Food Chemistry (2007), 102 (4), 1344-1351CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier B.V.)

A new pigment, resulting from the reaction between malvidin 3-glucoside and catechin in the presence of vanillin, was detected in a model soln. This newly formed anthocyanin-aryl-flavanol adduct was structurally characterized by 1D and 2D NMR and mass spectrometry, and its chromatic characteristics were studied by UV-Vis techniques. The new pigment was shown to have a wavelength of max. absorption in the visible region (λmax) of 549 nm, conferring on it a purple color, and a molar extinction coeff. value (ε) of 12,247 l · mol-1 · cm-1.

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157

Pissarra, J. ; Lourenco, S. ; Gonzalez-Paramas, A. M. ; Mateus, N. ; Buelga, C. S. ; Silva, A. M. S. ; De Freitas, V. Isolation and Structural Characterization of New Anthocyanin-Alkyl-Catechin Pigments. Food Chem. 2005, 90 , 81– 87, DOI: 10.1016/j.foodchem.2004.03.027

158

Pissarra, J. ; Lourenco, S. ; Gonzalez-Paramas, A. M. ; Mateus, N. ; Santos-Buelga, C. ; De Freitas, V. Formation of New Anthocyanin-Alkyl/Aryl-Flavanol Pigments in Model Solutions. Anal. Chim. Acta 2004, 513 , 215– 221, DOI: 10.1016/j.aca.2003.09.039

[Crossref], [CAS], Google Scholar

158

Formation of new anthocyanin-alkyl/aryl-flavanol pigments in model solutions

Pissarra, Joao; Lourenco, Sandra; Gonzalez-Paramas, Ana M.; Mateus, Nuno; Santos-Buelga, C.; De Freitas, Victor

Analytica Chimica Acta (2004), 513 (1), 215-221CODEN: ACACAM; ISSN:0003-2670. (Elsevier Science B.V.)

The contribution of the aldehyde compn. of wine spirit to the colorimetric changes in red Port wine was studied in model solns. by HPLC-diode array detection (DAD) and LC-MS. The reaction between anthocyanins, catechin and the several aldehydes was tested with dimers B4 and B2-3'-O-gallate, 2 of most abundant procyanidins dimers present in young Port wines. Both dimers reacted with oenin (malvidin 3-glucoside, mv3gl) mediated by several aldehydes (such as acetaldehyde, propionaldehyde, isovaleraldehyde, formaldehyde, isobutyraldehyde and benzaldehyde) leading to the formation of the resp. alkyl/aryl linked adducts. The structures of mv3gl-alkyl/aryl-dimer (B4 and B2-3'-O-gallate) and mv3gl-alkyl/aryl-cat ((-)-epicatechin and (-)-epicatechin-gallate) were assigned by LC/ESI-MS.

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159

Atanasova, V. ; Fulcrand, H. ; Le Guerneve, C. ; Cheynier, W. ; Moutounet, M. Structure of a New Dimeric Acetaldehyde Malvidin 3-Glucoside Condensation Product. Tetrahedron Lett. 2002, 43 , 6151– 6153, DOI: 10.1016/S0040-4039(02)01294-7

[Crossref], [CAS], Google Scholar

159

Structure of a new dimeric acetaldehyde malvidin 3-glucoside condensation product

Atanasova, Vessela; Fulcrand, Helene; Le Guerneve, Christine; Cheynier, Veronique; Moutounet, Michel

Tetrahedron Letters (2002), 43 (35), 6151-6153CODEN: TELEAY; ISSN:0040-4039. (Elsevier Science Ltd.)

A new pigment was detected in wine-like model soln. contg. malvidin 3-O-glucoside and acetaldehyde. This compd. was isolated, and its structure was investigated by UV, MS and NMR spectroscopies. The anal. data allowed identification of it to 8,8 Me methine-linked malvidin 3-O-glucoside dimer. The occurrence of this pigment was demonstrated in red wine. A polymeric fraction was also isolated from the model soln. and analyzed by LC/MS. Detection of Me methine-linked malvidin 3-O-glucoside oligomers proved that acetaldehyde mediated self-condensation of anthocyanins is possible, and that the C6 position of anthocyanins seems reactive as the C8 although to a lesser extent.

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Chassaing, S. ; Lefeuvre, D. ; Jacquet, R. ; Jourdes, M. ; Ducasse, L. ; Galland, S. ; Grelard, A. ; Saucier, C. ; Teissedre, P. L. ; Dangles, O. Physicochemical Studies of New Anthocyano-Ellagitannin Hybrid Pigments: About the Origin of the Influence of Oak C-Glycosidic Ellagitannins on Wine Color. Eur. J. Org. Chem. 2010, 2010 , 55– 63, DOI: 10.1002/ejoc.200901133

161

García-Estévez, I. ; Gavara, R. ; Alcalde-Eon, C. ; Rivas-Gonzalo, J. C. ; Quideau, S. ; Escribano-Bailón, M. T. ; Pina, F. Thermodynamic and Kinetic Properties of a New Myrtillin–Vescalagin Hybrid Pigment. J. Agric. Food Chem. 2013, 61 , 11569– 11578, DOI: 10.1021/jf403319u

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161

Thermodynamic and Kinetic Properties of a New Myrtillin-Vescalagin Hybrid Pigment

Garcia-Estevez, Ignacio; Gavara, Raquel; Alcalde-Eon, Cristina; Rivas-Gonzalo, Julian C.; Quideau, Stephane; Escribano-Bailon, M. Teresa; Pina, Fernando

Journal of Agricultural and Food Chemistry (2013), 61 (47), 11569-11578CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

During red wine maturation in contact with oak wood, C-glucosidic ellagitannins can react with anthocyanins, leading to new pigments. In this work the thermodn. and kinetic consts. of the network pH-dependent equil. of a new myrtillin (delphinidin 3-O-glucoside)-vescalagin hybrid pigment (1-deoxyvescalagin-(1β→8)-myrtillin) have been detd. by UV-visible absorption and stopped-flow expts. and compared to those detd. for myrtillin. The vescalagin substitution at the C-8' center of myrtillin entails important variations in the pigment behavior upon pH changes. The hybrid pigment showed lower pK'a and pKa values and a much higher value of Kt. As a consequence, at moderately acidic pH values (4 < pH < 6), the percentage of the hemiketal is much lower and the quinoidal base and the (E)-chalcone represent higher percentages relative to those for myrtillin. Therefore, the hybrid pigment can provide in slightly acidic or neutral solns. an exceptionally different color compared to that of myrtillin.

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Quideau, S. ; Jourdes, M. ; Lefeuvre, D. ; Montaudon, D. ; Saucier, C. ; Glories, Y. ; Pardon, P. ; Pourquier, P. The Chemistry of Wine Polyphenolic C-Glycosidic Ellagitannins Targeting Human Topoisomerase Ii. Chem. - Eur. J. 2005, 11 , 6503– 6513, DOI: 10.1002/chem.200500428

[Crossref], [PubMed], [CAS], Google Scholar

162

The chemistry of wine Polyphenolic C-glycosidic ellagitannins targeting human topoisomerase II

Quideau, Stephane; Jourdes, Michael; Lefeuvre, Dorothee; Montaudon, Daniele; Saucier, Cedric; Glories, Yves; Pardon, Patrick; Pourquier, Philippe

Chemistry - A European Journal (2005), 11 (22), 6503-6513CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

Polyphenolic nonahydroxyterphenoyl-contg. C-glycosidic oak ellagitannins are found in wine as a result of the aging of this beverage in oak-made barrels. Once in the slightly acidic wine (pH ∼ 3-4), some of these complex natural products such as (-)-vescalagin, but not its C-1 epimer (-)-castalagin, can capture grape-derived nucleophilic entities such as ethanol, the flavanols catechin and epicatechin, the anthocyanin oenin, and the thiolic glutathione to furnish condensation products with retention of configuration at the C-1 locus. A computer-aided rationale of this high diastereoselectivity is given. These condensation products can contribute to the modulation of organoleptic properties of the wine, as evidenced by the 23 nm bathochromic shift color absorbance obsd. with the novel oenin-based anthocyano-ellagitannin. Hydrolysis of 1 under solvolytic conditions furnished another novel compd. that we refer to as vescalene, in addn. to the known (-)-vescalin. Of pharmacol. importance is the fact that most of these found-in-wine water-sol. ellagitannin derivs. are much more potent than etoposide (VP-16) at inhibiting top2-mediated DNA de-catenation in vitro (top2 = topoisomerase II). The known (-)-vescalin and the novel vescalene fully inhibited top2 at 10 μM concn.!.

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Ferreira da Silva, P. ; Lima, J. C. ; Freitas, A. A. ; Shimizu, K. ; Maçanita, A. L. ; Quina, F. H. Charge-Transfer Complexation as a General Phenomenon in the Copigmentation of Anthocyanins. J. Phys. Chem. A 2005, 109 , 7329– 7338, DOI: 10.1021/jp052106s

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163

Charge-Transfer Complexation as a General Phenomenon in the Copigmentation of Anthocyanins

Ferreira da Silva, Palmira; Lima, Joao C.; Freitas, Adilson A.; Shimizu, Karina; Macanita, Antonio L.; Quina, Frank H.

Journal of Physical Chemistry A (2005), 109 (32), 7329-7338CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

Color intensification of anthocyanin solns. in the presence of natural polyphenols (copigmentation) is re-interpreted in terms of charge transfer from the copigment to the anthocyanin. Flavylium cations are shown to be excellent electron acceptors (Ered ≈ -0.3 V vs SCE). It is also demonstrated, for a large series of anthocyanin-copigment pairs, that the std. Gibbs free energy of complex formation decreases linearly with EAAnthoc-IPCop, the difference between the electron affinity of the anthocyanin, EAAnthoc, and the ionization potential of the copigment, IPCop. Based on this correlation, copigmentation strengths of potential candidates for copigments can be predicted.

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Alluis, B. ; Pérol, N. ; El hajji, H. ; Dangles, O. Water-Soluble Flavonol (=3-Hydroxy-2-Phenyl-4h-1-Benzopyran-4-One) Derivatives: Chemical Synthesis, Colouring, and Antioxidant Properties. Helv. Chim. Acta 2000, 83 , 428– 443, DOI: 10.1002/(SICI)1522-2675(20000216)83:2<428::AID-HLCA428>3.0.CO;2-J

[Crossref], [CAS], Google Scholar

164

Water-soluble flavonol (= 3-hydroxy-2-phenyl-4H-1-benzopyran-4-one) derivatives: chemical synthesis, coloring, and antioxidant properties

Alluis, Bertrand; Perol, Nathalie; El hajji, Hakima; Dangles, Olivier

Helvetica Chimica Acta (2000), 83 (2), 428-443CODEN: HCACAV; ISSN:0018-019X. (Verlag Helvetica Chimica Acta)

Water-sol. derivs. of rutin, a very common glycoside of quercetin (= 3,3',4',5,7-pentahydroxyflavone = 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one) and a potent plant antioxidant from the flavonol family, were synthesized by simple chem. procedures aimed at introducing carboxy or sulfo groups at the sugar moiety. Such derivs. form stable mol. complexes with malvin, a polyphenolic pigment from the anthocyanin family, and thereby prove to be very effective in the enhancement (hyperchromism) and variation (bathochromism) of natural colors. The H2O-solubilizing carboxylate and sulfate groups are shown to deeply modify the enthalpy-entropy balance of the pigment-flavonol complexation (copigmentation). A mol. interpretation of the complexation-induced bathochromic shift in the pigment VIS band is proposed. Finally, the H2O-sol. rutin derivs. are shown to retain the high antioxidant ability of rutin as evidenced by their efficient trapping of the colored radical DPPH (=2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl).

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Wang, Y. ; Chen, S. ; Yu, O. Metabolic Engineering of Flavonoids in Plants and Microorganisms. Appl. Microbiol. Biotechnol. 2011, 91 , 949– 956, DOI: 10.1007/s00253-011-3449-2

[Crossref], [PubMed], [CAS], Google Scholar

165

Metabolic engineering of flavonoids in plants and microorganisms

Wang, Yechun; Chen, Steven; Yu, Oliver

Applied Microbiology and Biotechnology (2011), 91 (4), 949-956CODEN: AMBIDG; ISSN:0175-7598. (Springer)

A review. Over 9,000 flavonoid compds. have been found in various plants, comprising one of the largest families of natural products. Flavonoids are an essential factor in plant interactions with the environment, often serving as the first line of defense against UV irradn. and pathogen attacks. Flavonoids are also major nutritional compds. in foods and beverages, with demonstrated health benefits. Some flavonoids are potent antioxidants, and specific flavonoid compds. are beneficial in many physiol. and pharmacol. processes. Therefore, engineering of flavonoid biosynthesis in plants or in microorganisms has significant scientific and economical importance. Construction of biosynthetic pathways in heterologous systems offers promising results for large-scale flavonoid prodn. by fermn. or bioconversion. Genomics and metabolomics now offer unprecedented tools for detailed understanding of the engineered transgenic organism and for developing novel technologies to further increase flavonoid prodn. yields. The authors summarize some of the recent metabolic engineering strategies in plants and microorganisms, with a focus on applications of metabolic flux anal. The authors are confident that these engineering approaches will lead to successful industrial flavonoid prodn. in the near future.

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Holton, T. A. ; Cornish, E. C. Genetics and Biochemistry of Anthocyanin Biosynthesis. Plant Cell 1995, 7 , 1071– 1083, DOI: 10.1105/tpc.7.7.1071

[Crossref], [PubMed], [CAS], Google Scholar

166

Genetics and biochemistry of anthocyanin biosynthesis

Holton, Timothy A.; Cornish, Edwina C.

Plant Cell (1995), 7 (7), 1071-83CODEN: PLCEEW; ISSN:1040-4651. (American Society of Plant Physiologists)

A review with many refs. on the more recent developments in gene isolation and characterization as to anthocyanin biosynthesis.

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Tanaka, Y. ; Sasaki, N. ; Ohmiya, A. Biosynthesis of Plant Pigments: Anthocyanins, Betalains and Carotenoids. Plant J. 2008, 54 , 733– 749, DOI: 10.1111/j.1365-313X.2008.03447.x

[Crossref], [PubMed], [CAS], Google Scholar

167

Biosynthesis of plant pigments: anthocyanins, betalains and carotenoids

Tanaka, Yoshikazu; Sasaki, Nobuhiro; Ohmiya, Akemi

Plant Journal (2008), 54 (4), 733-749CODEN: PLJUED; ISSN:0960-7412. (Blackwell Publishing Ltd.)

A review. Plant compds. that are perceived by humans to have color are generally referred to as pigments. Their varied structures and colors have long fascinated chemists and biologists, who have examd. their chem. and phys. properties, their mode of synthesis, and their physiol. and ecol. roles. Plant pigments also have a long history of use by humans. The major classes of plant pigments, with the exception of the chlorophylls, are reviewed here. Anthocyanins, a class of flavonoids derived ultimately from phenylalanine, are water-sol., synthesized in the cytosol, and localized in vacuoles. They provide a wide range of colors ranging from orange/red to violet/blue. In addn. to various modifications to their structures, their specific color also depends on co-pigments, metal ions and pH. They are widely distributed in the plant kingdom. The lipid-sol., yellow-to-red carotenoids, a subclass of terpenoids, are also distributed ubiquitously in plants. They are synthesized in chloroplasts and are essential to the integrity of the photosynthetic app. Betalains, also conferring yellow-to-red colors, are nitrogen-contg. water-sol. compds. derived from tyrosine that are found only in a limited no. of plant lineages. In contrast to anthocyanins and carotenoids, the biosynthetic pathway of betalains is only partially understood. All three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal. They also protect plants from damage caused by UV and visible light.

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Krisa, S. ; Waffo Téguo, P. ; Decendit, A. ; Deffieux, G. ; Vercauteren, J. ; Mérillon, J.-M. Production of 13c-Labelled Anthocyanins by Vitis Vinifera Cell Suspension Cultures. Phytochemistry 1999, 51 , 651– 656, DOI: 10.1016/S0031-9422(99)00068-0

[Crossref], [PubMed], [CAS], Google Scholar

168

Production of 13C-labelled anthocyanins by Vitis vinifera cell suspension cultures

Krisa, Stephanie; Teguo, Pierre Waffo; Decendit, Alain; Deffieux, Gerard; Vercauteren, Joseph; Merillon, Jean-Michel

Phytochemistry (1999), 51 (5), 651-656CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science Ltd.)

The use of plant cell cultures for producing isotopically (13C) labeled phenolic substances is reported. Vitis vinifera cells synthesize high levels of anthocyanins when they are cultured in a polyphenol synthesis-inducing medium. Three major anthocyanin monoglucosides found in red wine were identified in grape cells: cyanidin-3-O-β-glucoside, peonidin-3-O-β-glucoside, and malvidin-3-O-β-glucoside. Kinetic study of the intracellular level of phenylalanine and its metabolites showed that it is preferable to add this precursor to grape cell suspensions after the 5th day of culture, i.e. at the beginning of the exponential growth phase. After adding phenylalanine to the culture medium, its uptake was complete and the accumulation of anthocyanins in grape cells was stimulated. Incorporation of [1-13C]-phenylalanine into anthocyanins was measured by means of 13C satellites in the proton NMR spectrum. The maximal rate of 13C enrichment anthocyanins obtained with this technique reached 65%. The prodn. of 13C-labeled phenolic compds. was undertaken in order to investigate their absorption and metab. in humans.

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Yousef, G. G. ; Seigler, D. S. ; Grusak, M. A. ; Rogers, R. B. ; Knight, C. T. G. ; Kraft, T. F. B. ; Erdman, J. W. ; Lila, M. A. Biosynthesis and Characterization of 14c-Enriched Flavonoid Fractions from Plant Cell Suspension Cultures. J. Agric. Food Chem. 2004, 52 , 1138– 1145, DOI: 10.1021/jf035371o

[ACS Full Text ], [CAS], Google Scholar

169

Biosynthesis and Characterization of 14C-Enriched Flavonoid Fractions from Plant Cell Suspension Cultures

Yousef, Gad G.; Seigler, David S.; Grusak, Michael A.; Rogers, Randy B.; Knight, Christopher T. G.; Kraft, Tristan F. B.; Erdman, John W., Jr.; Lila, Mary Ann

Journal of Agricultural and Food Chemistry (2004), 52 (5), 1138-1145CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A range of radiolabeled anthocyanins, proanthocyanidins, and other flavonoids were accumulated by cell suspension cultures of two plant species, ohelo (Vaccinium pahalae) and grape (a Vitis hybrid, Bailey Alicant A), after providing uniformly labeled [14C]sucrose to the medium. Approx. 15% of administered label was recovered in a series of flavonoid-rich fractions varying in compn. Anthocyanins, and monomers to oligomers of proanthocyanidins, were labeled effectively and characterized from both species. Most of the proanthocyanidin oligomers were based on the flavan-3-ols (+)-catechin and (-)-epicatechin. Cyanidin and peonidin glycosides were the dominant forms of anthocyanins in both species. Whereas the predominant form of flavonoids identified from ohelo cell cultures was proanthocyanidins, grape cell cultures produced mostly anthocyanins. The labeled phytochems. were produced for use in subsequent in vivo animal feeding studies to gauge their bioavailability and accumulation in target organs.

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Hwang, E. I. ; Kaneko, M. ; Ohnishi, Y. ; Horinouchi, S. Production of Plant-Specific Flavanones by Escherichia Coli Containing an Artificial Gene Cluster. Appl. Environ. Microbiol. 2003, 69 , 2699– 2706, DOI: 10.1128/AEM.69.5.2699-2706.2003

[Crossref], [PubMed], [CAS], Google Scholar

170

Production of plant-specific flavanones by Escherichia coli containing an artificial gene cluster

Hwang, Eui Il; Kaneko, Masafumi; Ohnishi, Yasuo; Horinouchi, Sueharu

Applied and Environmental Microbiology (2003), 69 (5), 2699-2706CODEN: AEMIDF; ISSN:0099-2240. (American Society for Microbiology)

In plants, chalcones are precursors for a large no. of flavonoid-derived plant natural products and are converted to flavanones by chalcone isomerase or nonenzymically. Chalcones are synthesized from tyrosine and phenylalanine via the phenylpropanoid pathway involving phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate:CoA ligase (4CL), and chalcone synthase (CHS). For the purpose of prodn. of flavanones in Escherichia coli, three sets of an artificial gene cluster which contained three genes of heterologous origins-PAL from the yeast Rhodotorula rubra, 4CL from the actinomycete Streptomyces coelicolor A3(2), and CHS from the licorice plant Glycyrrhiza echinata-were constructed. The constructions of the three sets were done as follows: (i) PAL, 4CL, and CHS were placed in that order under the control of the T7 promoter (PT7) and the ribosome-binding sequence (RBS) in the pET vector, where the initiation codons of 4CL and CHS were overlapped with the termination codons of the preceding genes; (ii) the three genes were transcribed by a single PT7 in front of PAL, and each of the three contained the RBS at appropriate positions; and (iii) all three genes contained both PT7 and the RBS. These pathways bypassed C4H, a cytochrome P 450 hydroxylase, because the bacterial 4CL enzyme ligated CoA to both cinnamic acid and 4-coumaric acid. E. coli cells contg. the gene clusters produced two flavanones, pinocembrin from phenylalanine and naringenin from tyrosine, in addn. to their precursors, cinnamic acid and 4-coumaric acid. Of the three sets, the third gene cluster conferred on the host the highest ability to produce the flavanones. This is a new metabolic engineering technique for the prodn. in bacteria of a variety of compds. of plant and animal origin.

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Yan, Y. ; Chemler, J. ; Huang, L. ; Martens, S. ; Koffas, M. A. G. Metabolic Engineering of Anthocyanin Biosynthesis in Escherichia Coli . Appl. Environ. Microbiol. 2005, 71 , 3617– 3623, DOI: 10.1128/AEM.71.7.3617-3623.2005

[Crossref], [PubMed], [CAS], Google Scholar

171

Metabolic engineering of anthocyanin biosynthesis in Escherichia coli

Yan, Yajun; Chemler, Joseph; Huang, Lixuan; Martens, Stefan; Koffas, Mattheos A. G.

Applied and Environmental Microbiology (2005), 71 (7), 3617-3623CODEN: AEMIDF; ISSN:0099-2240. (American Society for Microbiology)

Anthocyanins are red, purple, or blue plant pigments that belong to the family of polyphenolic compds. collectively called flavonoids. Their demonstrated antioxidant properties and economic importance to the dye, fruit, and cut-flower industries have driven intensive research into their metabolic biosynthetic pathways. In order to produce stable, glycosylated anthocyanins from colorless flavanones such as naringenin and eriodictyol, a four-step metabolic pathway was constructed that contained plant genes from heterologous origins: flavanone 3β-hydroxylase from Malus domestica, dihydroflavonol 4-reductase from Anthurium andraeanum, anthocyanidin synthase (ANS) also from M. domestica, and UDP-glucose:flavonoid 3-O-glucosyltransferase from Petunia hybrida. Using two rounds of PCR, each one of the four genes was first placed under the control of the trc promoter and its own bacterial ribosome-binding site and then cloned sequentially into vector pK184. Escherichia coli cells contg. the recombinant plant pathway were able to take up either naringenin or eriodictyol and convert it to the corresponding glycosylated anthocyanin, pelargonidin 3-O-glucoside or cyanidin 3-O-glucoside. The produced anthocyanins were present at low concns., while most of the metabolites detected corresponded to their dihydroflavonol precursors, as well as the corresponding flavonols. The presence of side product flavonols is at least partly due to an alternate reaction catalyzed by ANS. This is the first time plant-specific anthocyanins have been produced from a microorganism and opens up the possibility of further prodn. improvement by protein and pathway engineering.

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Yan, Y. ; Li, Z. ; Koffas, M. A. G. High-Yield Anthocyanin Biosynthesis in Engineered Escherichia Coli. Biotechnol. Bioeng. 2008, 100 , 126– 140, DOI: 10.1002/bit.21721

[Crossref], [PubMed], [CAS], Google Scholar

172

High-yield anthocyanin biosynthesis in engineered Escherichia coli

Yan, Yajun; Li, Zhen; Koffas, Mattheos A. G.

Biotechnology and Bioengineering (2008), 100 (1), 126-140CODEN: BIBIAU; ISSN:0006-3592. (John Wiley & Sons, Inc.)

Anthocyanins are red, purple, or blue plant water-sol. pigments. In the past two decades, anthocyanins have received extensive studies for their anti-oxidative, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, and cardioprotective properties. In the present study, anthocyanin biosynthetic enzymes from different plant species were characterized and employed for pathway construction leading from inexpensive precursors such as flavanones and flavan-3-ols to anthocyanins in Escherichia coli. The recombinant E. coli cells successfully achieved milligram level prodn. of two anthocyanins, pelargonidin 3-O-glucoside (0.98 mg/L) and cyanidin 3-O-glucoside (2.07 mg/L) from their resp. flavanone precursors naringenin and eriodictyol. Cyanidin 3-O-glucoside was produced at even higher yields (16.1 mg/L) from its flavan-3-ol, (+)-catechin precursor. Further studies demonstrated that availability of the glucosyl donor, UDP-glucose, was the key metabolic limitation, while product instability at normal pH was also identified as a barrier for prodn. improvement. Therefore, various optimization strategies were employed for enhancing the homogenous synthesis of UDP-glucose in the host cells while at the same time stabilizing the final anthocyanin product. Such optimizations included culture medium pH adjustment, the creation of fusion proteins and the rational manipulation of E. coli metabolic network for improving the intracellular UDP-glucose metabolic pool. As a result, prodn. of pelargonidin 3-O-glucoside at 78.9 mg/L and cyanidin 3-O-glucoside at 70.7 mg/L was achieved from their precursor flavan-3-ols without supplementation with extracellular UDP-glucose. These results demonstrate the efficient prodn. of the core anthocyanins for the first time and open the possibility for their commercialization for pharmaceutical and nutraceutical applications.

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Eichenberger, M. ; Hansson, A. ; Fischer, D. ; Dürr, L. ; Naesby, M. Novo Biosynthesis of Anthocyanins in Saccharomyces Cerevisiae. FEMS Yeast Res. 2018, 18 , foy046, DOI: 10.1093/femsyr/foy046

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Zhang, J.-R. ; Trossat-Magnin, C. ; Bathany, K. ; Delrot, S. ; Chaudière, J. Oxidative Transformation of Leucocyanidin by Anthocyanidin Synthase from Vitis Vinifera Leads Only to Quercetin. J. Agric. Food Chem. 2019, 67 , 3595– 3604, DOI: 10.1021/acs.jafc.8b06968

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174

Oxidative transformation of leucocyanidin by anthocyanidin synthase from Vitis vinifera leads only to quercetin

Zhang, Jia-rong; Trossat-Magnin, Claudine; Bathany, Katell; Delrot, Serge; Chaudiere, Jean

Journal of Agricultural and Food Chemistry (2019), 67 (13), 3595-3604CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Anthocyanidin synthase from Vitis vinifera (VvANS) catalyzes the in vitro transformation of the natural isomer of leucocyanidin, 2R,3S,4S-cis-leucocyanidin, into 2R,4S-flavan-3,3,4-triol ([M + H]+, m/z 323) and quercetin. The C3-hydroxylation product 2R,4S-flavan-3,3,4-triol is first produced and its C3,C4-dehydration product is in tautomeric equil. with (+)-dihydroquercetin. The latter undergoes a second VvANS-catalyzed C3-hydroxylation leading to a 4-keto-2R-flavan-3,3-gem-diol which upon dehydration gives quercetin. The unnatural isomer of leucocyanidin, 2R,3S,4R-trans-leucocyanidin, is similarly transformed into quercetin upon C3,C4-dehydration, but unlike 3,4-cis-leucocyanidin, it also undergoes some C2,C3-dehydration followed by an acid-catalyzed hydroxyl group extrusion at C4 to give traces of cyanidin. Overall, the C3,C4-trans isomer of leucocyanidin is transformed into 2R,4R-flavan-3,3,4-triol (M + 1, m/z 323), (+)-DHQ, (-)-epiDHQ, quercetin, and traces of cyanidin. Our data bring the first direct observation of 3,4-cis-leucocyanidin- and 3,4-trans-leucocyanidin-derived 3,3-gem-diols, supporting the idea that the generic function of ANS is to catalyze the C3-hydroxylation of its substrates. No cyanidin is produced with the natural cis isomer of leucocyanidin, and only traces with the unnatural trans isomer, which suggests that anthocyanidin synthase requires other substrate(s) for the in vivo formation of anthocyanidins.

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Denish, P. R. ; Fenger, J.-A. ; Powers, R. ; Sigurdson, G. T. ; Grisanti, L. ; Guggenheim, K. G. ; Laporte, S. ; Li, J. ; Kondo, T. ; Magistrato, A. Discovery of a Natural Cyan Blue: A Unique Food-Sourced Anthocyanin Could Replace Synthetic Brilliant Blue. Sci. Adv. 2021, 7 , eabe7871, DOI: 10.1126/sciadv.abe7871

176

Butelli, E. ; Titta, L. ; Giorgio, M. ; Mock, H.-P. ; Matros, A. ; Peterek, S. ; Schijlen, E. G. W. M. ; Hall, R. D. ; Bovy, A. G. ; Luo, J. Enrichment of Tomato Fruit with Health-Promoting Anthocyanins by Expression of Select Transcription Factors. Nat. Biotechnol. 2008, 26 , 1301– 1308, DOI: 10.1038/nbt.1506

[Crossref], [PubMed], [CAS], Google Scholar

176

Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors

Butelli, Eugenio; Titta, Lucilla; Giorgio, Marco; Mock, Hans-Peter; Matros, Andrea; Peterek, Silke; Schijlen, Elio G. W. M.; Hall, Robert D.; Bovy, Arnaud G.; Luo, Jie; Martin, Cathie

Nature Biotechnology (2008), 26 (11), 1301-1308CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)

Dietary consumption of anthocyanins, a class of pigments produced by higher plants, has been assocd. with protection against a broad range of human diseases. However, anthocyanin levels in the most commonly eaten fruits and vegetables may be inadequate to confer optimal benefits. When expressed as 2 transcription factors from snapdragon in tomato, the fruit of the plants accumulated anthocyanins at levels substantially higher than previously reported for efforts to engineer anthocyanin accumulation in tomato and at concns. comparable to the anthocyanin levels found in blackberries and blueberries. Expression of the two transgenes enhanced the hydrophilic antioxidant capacity of tomato fruit 3-fold and resulted in fruit with intense purple coloration in both peel and flesh. In a pilot test, cancer-susceptible Trp53-/- mice fed a diet supplemented with the high-anthocyanin tomatoes showed a significant extension of life span.

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177

Zhu, Q. ; Yu, S. ; Zeng, D. ; Liu, H. ; Wang, H. ; Yang, Z. ; Xie, X. ; Shen, R. ; Tan, J. ; Li, H. Development of "Purple Endosperm Rice" by Engineering Anthocyanin Biosynthesis in the Endosperm with a High-Efficiency Transgene Stacking System. Mol. Plant 2017, 10 , 918– 929, DOI: 10.1016/j.molp.2017.05.008

[Crossref], [PubMed], [CAS], Google Scholar

177

Development of "Purple Endosperm Rice" by Engineering Anthocyanin Biosynthesis in the Endosperm with a High-Efficiency Transgene Stacking System

Zhu, Qinlong; Yu, Suize; Zeng, Dongchang; Liu, Hongmei; Wang, Huicong; Yang, Zhongfang; Xie, Xianrong; Shen, Rongxin; Tan, Jiantao; Li, Heying; Zhao, Xiucai; Zhang, Qunyu; Chen, Yuanling; Guo, Jingxing; Chen, Letian; Liu, Yao-Guang

Molecular Plant (2017), 10 (7), 918-929CODEN: MPOLA2; ISSN:1674-2052. (Elsevier)

Anthocyanins have high antioxidant activities, and engineering of anthocyanin biosynthesis in staple crops, such as rice (Oryza sativa L.), could provide health-promoting foods for improving human health. However, engineering metabolic pathways for biofortification remains difficult, and previous attempts to engineer anthocyanin prodn. in rice endosperm failed because of the sophisticated genetic regulatory network of its biosynthetic pathway. In this study, we developed a high-efficiency vector system for transgene stacking and used it to engineer anthocyanin biosynthesis in rice endosperm. We made a construct contg. eight anthocyanin-related genes (two regulatory genes from maize and six structural genes from Coleus) driven by the endosperm-specific promoters,plus a selectable marker and a gene for marker excision. Transformation of rice with this construct generated a novel biofortified germplasm "Purple Endosperm Rice" (called "Zijingmi" in Chinese), which has high anthocyanin contents and antioxidant activity in the endosperm. This anthocyanin prodn. results from expression of the transgenes and the resulting activation (or enhancement) of expression of 13 endogenous anthocyanin biosynthesis genes that are silenced or expressed at low levels in wild-type rice endosperm. This study provides an efficient, versatile toolkit for transgene stacking and demonstrates its use for successful engineering of a sophisticated biol. pathway, suggesting the potential utility of this toolkit for synthetic biol. and improvement of agronomic traits in plants.

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178

Pina, F. ; Melo, M. J. ; Laia, C. A. T. ; Parola, A. J. ; Lima, J. C. Chemistry and Applications of Flavylium Compounds: A Handful of Colours. Chem. Soc. Rev. 2012, 41 , 869– 908, DOI: 10.1039/C1CS15126F

[Crossref], [PubMed], [CAS], Google Scholar

178

Chemistry and applications of flavylium compounds: a handful of colours

Pina, Fernando; Melo, Maria J.; Laia, Cesar A. T.; Parola, A. Jorge; Lima, Joao C.

Chemical Society Reviews (2012), 41 (2), 869-908CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Flavylium compds. are versatile mols. that comprise anthocyanins, the ubiquitous colorants used by Nature to confer color to most flowers and fruits. They have found a wide range of applications in human technol., from the millenary color paints described by the Roman architect Vitruvius, to their use as food additives, combining color and antioxidant effects, and even as light absorbers in solar cells aiming at a greener solar energy conversion. Their rich complexity derives in part from their ability to switch between a variety of species (flavylium cations, neutral quinoidal bases, hemiketals and chalcones, and neg. charged phenolates) by means of external stimuli, such as pH, temp. and light. This crit. review describes (i) the historical advancements in the understanding of the equil. of their chem. reaction networks; (ii) their thermodn. and kinetics; (iii) the mechanisms underlying their color development, such as co-pigmentation and host-guest interactions; (iv) the photophysics and photochem. that lead to photochromism; and (v) applications in solar cells, models for optical memories, photochromic soft materials such as ionic liqs. and gels, and their properties in solid state materials (274 refs.).

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Pina, F. ; Melo, M. J. ; Maestri, M. ; Ballardini, R. ; Balzani, V. Photochromism of 4'-Methoxyflavylium Perchlorate. A ''Write-Lock-Read-Unlock-Erase'' Molecular Switching System. J. Am. Chem. Soc. 1997, 119 , 5556– 5561, DOI: 10.1021/ja9704646

[ACS Full Text ], [CAS], Google Scholar

179

Photochromism of 4'-Methoxyflavylium Perchlorate. A "Write-Lock-Read-Unlock-Erase" Molecular Switching System

Pina, Fernando; Melo, Maria Joao; Maestri, Mauro; Ballardini, Roberto; Balzani, Vincenzo

Journal of the American Chemical Society (1997), 119 (24), 5556-5561CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

In aq. soln. (pH 2-8) the thermodynamically stable form of the 4'-methoxyflavylium ion (I) is its hydrated deriv. trans-4'-methoxychalcone, (II). II shows a broad absorption band, at λmax 350 nm. In acid medium, irradn. of II with near-UV light causes strong spectral changes with five isosbestic points and appearance of a very intense band in the visible region with max. at 435 nm, corresponding to the I. Irradn. of II causes a trans → cis photoisomerization reaction (Φ = 0.04 at λexc = 365 nm), which is followed by 100% conversion of the cis-chalcone form to I. I is photochem. inactive and thermally inert in acid medium (half-life of the back conversion at 25° in the dark is 815 days at pH 1.0 and 20 h at pH 4.3, resp.). At high temp. (>50°) and/or pH ≥3, however, I can be quant. converted back to II (half-life of 15 min at pH 4.0 and 60°). Because of this behavior, this represents a novel mol. system in which the color can be controlled by light and changes in temp. and/or pH. The ability to photochem. convert the stable and colorless II to the kinetically inert and colored I, and the possibility to reconvert I to II at high temp. or by a pH jump makes the system well-suited as the basis for an optical memory device with multiple storage and nondestructive readout capacity through a write-lock-read-unlock-erase cycle.

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Basilio, N. ; Pina, F. Chemistry and Photochemistry of Anthocyanins and Related Compounds: A Thermodynamic and Kinetic Approach. Molecules 2016, 21 , 1502, DOI: 10.3390/molecules21111502

[Crossref], [CAS], Google Scholar

180

Chemistry and photochemistry of anthocyanins and related compounds: a thermodynamic and kinetic approach

Basilio, Nuno; Pina, Fernando

Molecules (2016), 21 (11), 1502/1-1502/25CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

Anthocyanins are identified by the resp. flavylium cation, which is only one species of a multistate of different mols. reversibly interconverted by external inputs such as pH, light and temp. The flavylium cation (acidic form) is involved in an apparent acid-base reaction, where the basic species is the sum of quinoidal base, hemiketal and cis- and trans-chalcones, their relative fraction depending on the substitution pattern of the flavylium cation. The full comprehension of this complex system requires a thermodn. and kinetic approach. The first consists in drawing an energy level diagram where the relative positions of the different species are represented as a function of pH. On the other hand, the kinetic approach allows measuring the rates of the reactions that interconnect reversibly the multistate species. The kinetics is greatly dependent on the existence or not of a high cis-trans isomerization barrier. In this work, the procedure to obtain the energy level diagram and the rates of interconversion in the multistate in both cases (low or high isomerization barrier) are described. Practical examples of this approach are presented to illustrate the theory, and recently reported applications based on host-guest complexes are reviewed.

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181

Brouillard, R. ; Iacobucci, G. A. ; Sweeny, J. G. Chemistry of Anthocyanins Pigments.9. Uv Visible Spectrophotometric Deetrmination of the Acidity Constants of Apigeninidin and 3 Related 3-Deoxyflavylium Salts. J. Am. Chem. Soc. 1982, 104 , 7585– 7590, DOI: 10.1021/ja00390a033

[ACS Full Text ], [CAS], Google Scholar

181

Chemistry of anthocyanin pigments. 9. UV-visible spectrophotometric determination of the acidity constants of apigeninidin and three related 3-deoxyflavylium salts

Brouillard, R.; Iacobucci, G. A.; Sweeny, J. G.

Journal of the American Chemical Society (1982), 104 (26), 7585-90CODEN: JACSAT; ISSN:0002-7863.

The equil. consts. for the isomerization and hydration of 3-deoxyanthocyanidins in H2O at 25° are detd. by the pH-jump method. According to their particular substitution patterns, hydroxylated flavylium salts can exist in slightly acidic mediums in the quinoidal bases A, he carbinol pseudobase B, and the chalcone pseudobase C forms. 4',5,7-Trihydroxyflavylium (apigeninidin) and 4'-methoxy-4-methyl-5,7-dihydroxyflavylium chlorides, exist essentially as a mixt. of neutral A, B, and C; the colored species A is the most abundant. As expected, 4',7-dihydroxyflavylium chloride is stable in the open chalcone structure C in agreement with the catalytic light effect generally obsd. for the ring-closure reaction of this species leading to the flavylium cation AH+. Only for the monohydroxylated pigment 4'-methoxy-4-methyl-7-hydroxyflavylium chloride is the quinoidal base A perfectly stable, whatever the pH. In contrast to natural anthocyanins, the hydration of the pyrylium ring is less efficient and occurs, therefore, at much higher pH values (pH 5-6). Proton loss from the phenolic acidic hydroxyl groups of the flavylium cation takes place in the usual acidity range (pH 4-5), indicating that these groups are strongly H-bonded to the surrounding H2O mols. The chalcone content is much higher than for the anthocyanins, and for 4',7-dihydroxyflavylium chloride for instance, the value for the equil. ratio of the chalcone to the carbinol is as high as 20.6.

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182

Brouillard, R. ; Delaporte, B. ; Dubois, J. E. Chemistry of Anthocyanins Pigments.3. Relaxation Amplitudes in Ph-Jump Experiments. J. Am. Chem. Soc. 1978, 100 , 6202– 6205, DOI: 10.1021/ja00487a041

[ACS Full Text ], [CAS], Google Scholar

182

Chemistry of anthocyanin pigments. 3. Relaxation amplitudes in pH-jump experiments

Brouillard, Raymond; Delaporte, Bernard; Dubois, Jacques Emile

Journal of the American Chemical Society (1978), 100 (19), 6202-5CODEN: JACSAT; ISSN:0002-7863.

A pH-jump method is used to det. the equil. consts. of the proton transfer, hydration, and tautomeric reactions of malvidin 3-glucoside and malvidin 3,5-diglucoside. The method gives excellent agreement between calcd. and obsd. amplitudes and offers simplicity and an absence of secondary phys. effects.

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183

Alejo-Armijo, A. ; Mendoza, J. ; Parola, A. J. ; Pina, F. The Chemical Evolution of the Colour Systems Generated by Riccionidin a, 3-Deoxyanthocyanidins and Anthocyanins. Phytochemistry 2020, 174 , 112339, DOI: 10.1016/j.phytochem.2020.112339

[Crossref], [PubMed], [CAS], Google Scholar

183

Chemical evolution of the colour systems generated by riccionidin A, 3-deoxyanthocyanidins and anthocyanins

Alejo-Armijo, A.; Mendoza, Johan; Parola, A. Jorge; Pina, Fernando

Phytochemistry (Elsevier) (2020), 174 (), 112339CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Ltd.)

The kinetics and thermodn. (in acidic solns.) of the five chem. species reversibly interconnected by external stimuli (a multistate), such as pH and light, generated by the liverworts colorant riccionidin A were investigated. The degrdn. products of the multistate formed after 10 days at neutral pH were identified. The behavior of riccionidin A multistate was compared with previous results reported for the equiv. systems based on 3-deoxyanthocyanidins (found in mosses and ferns) and anthocyanins (ubiquitous in angiosperms). The five chem. species have mutatis mutandis similar structures in the three multistates. The most dramatic difference is the extremely slow interconversion rate between flavylium cation and trans-chalcone in riccionidin A and related compds. multistates (tens of days) when compared with deoxyanthocyanins (a few days) and anthocyanins (several hours), at room temp. The mole fraction distribution of the five species that constitute the multistate as a function of pH is also different in the three families of compds. Some considerations regarding the chem. evolution of the three systems are given.

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184

Brouillard, R. ; Dubois, J. E. Mechanism of Structural Transformations of Anthocyanins in Acidic Media. J. Am. Chem. Soc. 1977, 99 , 1359– 1364, DOI: 10.1021/ja00447a012

[ACS Full Text ], [CAS], Google Scholar

184

Mechanism of the structural transformations of anthocyanins in acidic media

Brouillard, Raymond; Dubois, Jacques-Emile

Journal of the American Chemical Society (1977), 99 (5), 1359-64CODEN: JACSAT; ISSN:0002-7863.

In acidic aq. media (pH 1-6), there are three forms of malvin: the flavylium cation I (R = β-D-glucopyranosyl), the carbinol, and the quinonoidal base. Equilibrium between the two neutral forms occurs via the flavylium cation and the equil. const. [carbinol]/[base] is 1.6 (± 0.5) × 102 at 4° ;a relaxation technique was used to det. the rate consts for neutralization (endotherm) of the base, for hydration ofI via formation of a C-O bond and proton transfer,and for the reverse of the reactions.

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185

McClelland, R. A. ; Gedge, S. Hydration of the Flavylium Ion. J. Am. Chem. Soc. 1980, 102 , 5838– 5848, DOI: 10.1021/ja00538a024

[ACS Full Text ], [CAS], Google Scholar

185

Hydration of the flavylium ion

McClelland, Robert A.; Gedge, Sherrin

Journal of the American Chemical Society (1980), 102 (18), 5838-48CODEN: JACSAT; ISSN:0002-7863.

Spectral and kinetic studies were carried out on the transformations undergone in aq. soln. by flavylium ions and I (R = H, Me, MeO). Seven species were identified under various pH conditions, i.e., the flavylium ion, 2 pseudobases, 4-hydroxy adducts and the cis-2-hydroxychalcones and their ionized forms. Equil. between the various species are described and rate and equil. consts. were detd.

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186

Leydet, Y. ; Gavara, R. ; Petrov, V. ; Diniz, A. M. ; Parola, A. J. ; Lima, J. C. ; Pina, F. The Effect of Self-Aggregation on the Determination of the Kinetic and Thermodynamic Constants of the Network of Chemical Reactions in 3-Glucoside Anthocyanins. Phytochemistry 2012, 83 , 125– 135, DOI: 10.1016/j.phytochem.2012.06.022

[Crossref], [PubMed], [CAS], Google Scholar

186

The effect of self-aggregation on the determination of the kinetic and thermodynamic constants of the network of chemical reactions in 3-glucoside anthocyanins

Leydet, Yoann; Gavara, Raquel; Petrov, Vesselin; Diniz, Ana M.; Parola, A. Jorge; Lima, Joao C.; Pina, Fernando

Phytochemistry (Elsevier) (2012), 83 (), 125-135CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Ltd.)

The six most common 3-glucoside anthocyanins, pelargonidin-3-glucoside, peonidin-3-glucoside, delphinidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-glucoside and petunidin-3-glucoside were studied in great detail by NMR, UV-vis absorption and stopped flow. For each anthocyanin, the thermodn. and kinetic consts. of the network of chem. reactions were calcd. at different anthocyanin concn., from 6 × 10-6 M up to 8 × 10-4 M; an increasing of the flavylium cation acidity const. to give quinoidal base and a decreasing of the flavylium cation hydration const. to give hemiketal were obsd. by increasing the anthocyanin concn. These effects are attributed to the self-aggregation of the flavylium cation and quinoidal base, which is stronger in the last case. The UV-vis and 1H NMR spectral variations resulting from the increasing of the anthocyanin concn. were discussed in terms of two aggregation models; monomer-dimer and isodesmic, the last one considering the formation of higher order aggregates possessing the same aggregation const. of the dimer. The self-aggregation const. of flavylium cation at pH = 1.0, calcd. by both models increases by increasing the no. of methoxy (-OCH3) or hydroxy (-OH) substituents following the order: myrtillin (2 -OH), oenin (2 -OCH3), 3-OGl-petunidin (1 -OH, 1 -OCH3), kuromanin (1 -OH), 3-OGl-peonidin (1 -OCH3) and callistephin (none). Evidence for flavylium aggregates possessing a shape between J and H was achieved, as well as for the formation of higher order aggregates.

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187

Macanita, A. L. ; Moreira, P. F. ; Lima, J. C. ; Quina, F. H. ; Yihwa, C. ; Vautier-Giongo, C. Proton Transfer in Anthocyanins and Related Flavylium Salts. Determination of Ground-State Rate Constants with Nanosecond Laser Flash Photolysis. J. Phys. Chem. A 2002, 106 , 1248– 1255, DOI: 10.1021/jp0140421

[ACS Full Text ], [CAS], Google Scholar

187

Proton Transfer in Anthocyanins and Related Flavylium Salts. Determination of Ground-State Rate Constants with Nanosecond Laser Flash Photolysis

Macanita, Antonio L.; Moreira, Paulo F., Jr.; Lima, Joao C.; Quina, Frank H.; Yihwa, Chang; Vautier-Giongo, Carolina

Journal of Physical Chemistry A (2002), 106 (7), 1248-1255CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

A new method for the detn. of proton-transfer rate consts. in the ground state of anthocyanins and related flavylium salts is described. The method is based on the known pKa shift of phenols on going from ground to the first excited singlet state coupled to the typically very fast excited state proton transfer and very short lifetimes (picosecond range) occurring in these compds. Under these conditions, a nanosecond light pulse instantaneously shifts the ground-state equil., after which the ground-state transients can be monitored with nanosecond or microsecond resoln. The method is successfully applied to the detn. of the deprotonation rate consts., kd, of two synthetic flavylium salts and a natural anthocyanin (7-hydroxy-4-methylflavylium chloride (HMF), 4',7-dihydroxyflavylium chloride (DHF), and malvidin-3-glucoside chloride (oenin), resp.) and the protonation rate consts., kp, of their conjugate quinonoidal bases in the ground state. For all three flavylium cations, the protonation of the ground state base form is essentially diffusion-controlled, and the deprotonation occurs in the submicrosecond range. Directly detd. rate consts. are 2 orders of magnitude greater than previous values estd. for oenin by T jump. The flash photolysis approach used in the present work seems to be the only technique available for measurement of the kinetics of proton transfer in anthocyanins. In addn., results show clear laser-induced perturbation of the ground-state protonation of oenin, providing the first direct evidence for excited-state proton transfer as a significant energy dissipation process in natural anthocyanins.

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188

Basilio, N. ; Al Bittar, S. ; Mora, N. ; Dangles, O. ; Pina, F. Analogs of Natural 3-Deoxyanthocyanins: O-Glucosides of the 4 ',7-Dihydroxyflavylium Ion and the Deep Influence of Glycosidation on Color. Int. J. Mol. Sci. 2016, 17 , 1751, DOI: 10.3390/ijms17101751

[Crossref], [CAS], Google Scholar

188

Analogs of natural 3-deoxyanthocyanins: O-glucosides of the 4',7-dihydroxyflavylium ion and the deep influence of glycosidation on color

Basilio, Nuno; Al Bittar, Sheiraz; Mora, Nathalie; Dangles, Olivier; Pina, Fernando

International Journal of Molecular Sciences (2016), 17 (10), 1751/1-1751/14CODEN: IJMCFK; ISSN:1422-0067. (MDPI AG)

3-Deoxyanthocyanidins and their O-β-d-glucosides are natural pigments abundant in black sorghum. O-glycosylation can perturb the acid-base properties of the chromophore and lower its electron d. with a large impact on the distribution of colored and colorless forms in aq. soln. In this work, the influence of O-glycosidation on color is systematically studied from a series of 3-deoxyanthocyanin analogs. The pH- and light-dependent reversible reactions of 7-β-D-glucopyranosyloxy-4'-hydroxyflavylium (P3) and 4'-β-D-glucopyranosyloxy-7-hydroxyflavylium (P5) were completely characterized. Except P5, the chalcone forms of the pigments exhibit a high cis-trans isomerization barrier that allows a pseudo-equil. involving all species except the trans-chalcone. At equil., only the flavylium cation and trans-chalcone are obsd. Glycosidation of C7-OH accelerates hydration and strongly slows down cis-trans isomerization with the pH dependence of the apparent isomerization rate const. shifting from a bell-shaped curve to a sigmoid. The color of P5 is much more stable than that of its regioisomer P3 in near-neutral conditions.

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Rusishvili, M. ; Grisanti, L. ; Laporte, S. ; Micciarelli, M. ; Rosa, M. ; Robbins, R. J. ; Collins, T. ; Magistrato, A. ; Baroni, S. Unraveling the Molecular Mechanisms of Color Expression in Anthocyanins. Phys. Chem. Chem. Phys. 2019, 21 , 8757– 8766, DOI: 10.1039/C9CP00747D

[Crossref], [PubMed], [CAS], Google Scholar

189

Unraveling the molecular mechanisms of color expression in anthocyanins

Rusishvili, Mariami; Grisanti, Luca; Laporte, Sara; Micciarelli, Marco; Rosa, Marta; Robbins, Rebecca J.; Collins, Tom; Magistrato, Alessandra; Baroni, Stefano

Physical Chemistry Chemical Physics (2019), 21 (17), 8757-8766CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)

Anthocyanins are a broad family of natural dyes, increasingly finding application as substitutes for artificial colorants in the food industry. In spite of their importance and ubiquity, the mol. principles responsible for their extreme color variability are poorly known. We address these mechanisms by computer simulations and photoabsorption expts. of cyanidin-3-O-glucoside in water soln., as a proxy for more complex members of the family. Exptl. results are presented in the range of pH 1-9, accompanied by a comprehensive systematic computational study across relevant charge states and tautomers. The computed spectra are in excellent agreement with the expts., providing unprecedented insight into the complex behavior underlying color expression in these mols. Besides confirming the importance of the mol.'s charge state, we also unveil the hitherto unrecognized role of internal distortions in the chromophore, which affect its degree of conjugation, modulating the optical gap and in turn the color. This entanglement of structural and electronic traits is also shared by other members of the anthocyanin family (e.g. pelargonidin and delphinidin) highlighting a common mechanism for color expression across this important family of natural dyes.

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190

Fenger, J.-A. ; Roux, H. ; Robbins, R. J. ; Collins, T. M. ; Dangles, O. The Influence of Phenolic Acyl Groups on the Color of Purple Sweet Potato Anthocyanins and Their Metal Complexes. Dyes Pigm. 2021, 185 , 108792, DOI: 10.1016/j.dyepig.2020.108792

[Crossref], [CAS], Google Scholar

190

The influence of phenolic acyl groups on the color of purple sweet potato anthocyanins and their metal complexes

Fenger, Julie-Anne; Roux, Hugo; Robbins, Rebecca J.; Collins, Thomas M.; Dangles, Olivier

Dyes and Pigments (2021), 185 (Part_A), 108792CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Anthocyanins from purple sweet potato (PSP) are peonidin and cyanidin glycosides acylated by p-hydroxycinnamic and p-hydroxybenzoic acids. For six individual PSP pigments, the thermodn. consts. of proton transfer and water addn. were detd., from which the speciation diagrams for the colored and colorless forms and the UV-visible spectra of individual colored forms could be constructed. The data confirm that acylation by phenolic acids protects the chromophore against water addn. (a consequence of acyl - anthocyanidin π-stacking interactions) and that this protection depends on the type and no. of acyl residues, diacylation being much more efficient than monoacylation, and p-hydroxycinnamoyl more efficient than p-hydroxybenzoyl. Most PSP anthocyanins can bind metal ions (Fe2+, Al3+) through their cyanidin chromophore and/or their caffeoyl residue(s). At pH 7, a cyanidin glycoside bearing a caffeoyl residue can bind a single metal ion by simultaneous involvement of its two binding units. With Fe2+ a strong bluing effect was obsd. Although the caffeoyl residues efficiently slow down color loss, their redox activity actually accelerates the thermal degrdn. of anthocyanins. Consistently, two-electron autoxidn. of anthocyanins bearing caffeoyl residues could be evidenced by UPLC-MS/DAD anal. These new pigments possibly stem from intramol. coupling between the chromophore and o-quinones derived from the caffeoyl residues.

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191

Pina, F. Chemical Applications of Anthocyanins and Related Compounds. A Source of Bioinspiration. J. Agric. Food Chem. 2014, 62 , 6885– 6897, DOI: 10.1021/jf404869m

[ACS Full Text ], [CAS], Google Scholar

191

Chemical Applications of Anthocyanins and Related Compounds. A Source of Bioinspiration

Pina, Fernando

Journal of Agricultural and Food Chemistry (2014), 62 (29), 6885-6897CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A review. Independently of the natural or synthetic origin, flavylium derivs. follow the same network of chem. reactions. Actually, the flavylium cation is stable only at low pH values. Increasing the pH gives rise to the formation of several species: quinoidal bases, hemiketal, cis- and trans-chalcones, and their deprotonated forms. A deep knowledge of the thermodn. and kinetics of these species is an essential tool to practical applications of these compds., in particular, in the domain of food chem. In this work the network of chem. reactions involving flavylium derivs. is presented, and the resp. thermodn. and kinetics are discussed in detail, including the math. expressions and a step-by-step procedure to calc. all of the rate and equil. consts. of the system. Examples of systems possessing a high or low cis-trans isomerization barrier are shown. Recent practical applications of anthocyanins and related compds. illustrate the potential of the flavylium-based family of compds.

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192

Mendoza, J. ; Basilio, N. ; de Freitas, V. ; Pina, F. New Procedure to Calculate All Equilibrium Constants in Flavylium Compounds: Application to the Copigmentation of Anthocyanins. ACS Omega 2019, 4 , 12058– 12070, DOI: 10.1021/acsomega.9b01066

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192

New Procedure To Calculate All Equilibrium Constants in Flavylium Compounds: Application to the Copigmentation of Anthocyanins

Mendoza, Johan; Basilio, Nuno; de Freitas, Victor; Pina, Fernando

ACS Omega (2019), 4 (7), 12058-12070CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)

A new exptl. procedure to calc. all equil. consts. of the anthocyanins and related compds. multistate of species, including those in basic medium is reported. The procedure is based in series of pH jumps monitored by stopped flow from an extended pH range of solns. at the pseudo-equil. (when there is no significant formation of trans-chalcones) or at the equil. to pH = 1.0. The exptl. procedure is described for the anthocyanins model compd. 4'-hydroxyflavylium, which exhibits a peculiar behavior in moderately acidic medium, because quinoidal base, hemiketal and cis-chalcone have similar mole fractions at the pseudo-equil., permitting a good discrimination between these species. The exptl. procedure can be extended to the co-pigmentation phenomenon and allow the calcn. of the 1:1 co-pigmentation consts. of flavylium cation, quinoidal base, hemiketal, cis and trans chalcones (this last from the equil.) and the resp. ionized forms. The method was applied to calc. the co-pigmentation consts. of the model compd. 4'-hydroxyflavylium as well as malvidin-3-glucoside with caffeine. In this last compd. the highest interaction takes place with quinoidal base (K=303 M-1) and flavylium cation (K = 134 M-1), and in less extent with ionized quinoidal base (K = 43 M-1) and cis-chalcone (K = 17 M-1). The caffeine interaction with hemiketal and the other ionized species is negligible.

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193

Mendoza, J. ; Basilio, N. ; Pina, F. ; Kondo, T. ; Yoshida, K. Rationalizing the Color in Heavenly Blue Anthocyanin: A Complete Kinetic and Thermodynamic Study. J. Phys. Chem. B 2018, 122 , 4982– 4992, DOI: 10.1021/acs.jpcb.8b01136

[ACS Full Text ], [CAS], Google Scholar

193

Rationalizing the Color in Heavenly Blue Anthocyanin: A Complete Kinetic and Thermodynamic Study

Mendoza, Johan; Basilio, Nuno; Pina, Fernando; Kondo, Tadao; Yoshida, Kumi

Journal of Physical Chemistry B (2018), 122 (19), 4982-4992CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnvFansro%253D&md5=b910cee096a2bd530e2ae6171cda596c

194

Moloney, M. ; Robbins, R. J. ; Collins, T. M. ; Kondo, T. ; Yoshida, K. ; Dangles, O. Red Cabbage Anthocyanins: The Influence of D-Glucose Acylation by Hydroxycinnamic Acids on Their Structural Transformations in Acidic to Mildly Alkaline Conditions and on the Resulting Color. Dyes Pigm. 2018, 158 , 342– 352, DOI: 10.1016/j.dyepig.2018.05.057

[Crossref], [CAS], Google Scholar

194

Red cabbage anthocyanins: The influence of D-glucose acylation by hydroxycinnamic acids on their structural transformations in acidic to mildly alkaline conditions and on the resulting color

Moloney, Micheal; Robbins, Rebecca J.; Collins, Tom M.; Kondo, Tadao; Yoshida, Kumi; Dangles, Olivier

Dyes and Pigments (2018), 158 (), 342-352CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Anthocyanins acylated by hydroxycinnamic acids (HCAs) are fascinating plant pigments that express a variety of red, purple and blue colors by combining multiple structural transformations and mol. interactions. Acylated anthocyanins are also a promising alternative to artificial food colorants. In this work, the mono- and diacylated anthocyanins of red cabbage have been extensively studied by NMR, UV-visible spectroscopy and CD. Our results show that HCA residues promote π-stacking interactions between the phenolic nuclei, thereby efficiently protecting the cyanidin chromophore against water addn. leading to colorless forms. For instance, the rate const. of water addn. is ca. 0.3 s-1 for the nonacylated pigment, in the range 0.1-0.2 s-1 for the three monoacylated pigments and of the order of 0.01 s-1 for the three diacylated pigments. By contrast, the rate const. of water elimination and the thermodn. consts. of proton transfer between the cationic, neutral and anionic colored forms are only weakly affected by acylation. Thus, through π-stacking interactions, the diacylated anthocyanins maintain a higher percentage of cationic and neutral colored forms at equil. in mildly acidic conditions. In neutral - mildly alk. conditions, the diacylated anthocyanins adopt persistent anionic forms (very slow water addn.), expressing intense blue colors. NMR and CD data suggest that a combination of cyanidin - HCA (intramol. copigmentation) and cyanidin - cyanidin (self-assocn.) interactions operates in the color-stabilizing mechanism, which is also translated in an improved resistance against the long-term color loss in mildly alk. conditions, signalling the irreversible degrdn. of the chromophore.

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195

Dangles, O. ; Saito, N. ; Brouillard, R. Kinetic and Thermodynamic Control of Flavylium Hydration in the Pelargonidin Cinnamic Acid Complexation - Origin of the Extraordinary Flower Color Diversity of Pharbitis-Nil. J. Am. Chem. Soc. 1993, 115 , 3125– 3132, DOI: 10.1021/ja00061a011

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195

Kinetic and thermodynamic control of flavylium hydration in the pelargonidin-cinnamic acid complexation. Origin of the extraordinary flower color diversity of Pharbitis nil

Dangles, Olivier; Saito, Norio; Brouillard, Raymond

Journal of the American Chemical Society (1993), 115 (8), 3125-32CODEN: JACSAT; ISSN:0002-7863.

During the past decade, structural elucidation of heavily substituted anthocyanins present, for instance, in the bright ornamental flowers, has brought to light the role played by sugar and phenolic acid residues in the fascinating pigmentation properties of such natural mols. It now appears that higher plants have developed in their flowers and fruits extremely sensitive and powerful color stabilization and variation mechanism related to the presence of glycosidic acylated anthocyanidins. In these mols., a sugar unit, bearing the anthocyanidin chromophore and a cinnamic acid residue, brings sufficient flexibility for the latter two moieties to interact through space, according to a mechanism called intramol. copigmentation. Here, on the basis of UV-visible spectroscopic measurements, kinetic and thermodn. evidence supporting the existence of folded conformations which involve the stacking of either one cinnamic acid residue on the anthocyanidin chromophore or two cinnamic acid residues on both sides of the chromophore (sandwich-type assocn.) is given. Pigments investigated in this work were obtained from red-purple cultivars of Pharbitis nil (morning glory). They correspond to four pelargonidin derivs. [I; R = R1 = R2 = H; R = β-D-glucopyranosyl, R1 = H, R2 = trans-caffeyl; R = β-D-glucopyranosyl, R1 = trans-3-O-(β-D-glucopyranosyl)caffeyl, R2 = H;]: one which is not acylated (ref. compd. I; R = R1 = R2 = H), two of the monoacylated type [I; R = β-D-glucopyranosyl, R1 = H, R2 = trans-caffeyl; R = β-D-glucopyranosyl, R1 = trans-3-O-(β-D-glucopyranosyl)caffeyl, R2 = H], and one diacylated [I; R = β-D-glucopyranosyl, R1 = trans-3-O-(β-D-glucopyranosyl)caffeyl, R2 = trans-caffeyl]. The cornerstone of our study rests on the hydration reaction of the anthocyanidin chromophore when in its flavylium form. Indeed, the kinetic and thermodn. parameters of this reaction and the way they are affected by the presence of one or two cinnamic acid residue(s) is of considerable value in the understanding of anthocyanin intramol. complex formation. Copigmentation more frequently occurs as an intermol. process, pigment and copigment being in that case two distinct mols. By running competitive intra- and intermol. copigmentation expts., we also demonstrate that the phenomenon in which pigment and copigment are linked together is much more efficient.

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Oliveira, H. ; Basilio, N. ; Pina, F. ; Fernandes, I. ; de Freitas, V. ; Mateus, N. Purple-Fleshed Sweet Potato Acylated Anthocyanins: Equilibrium Network and Photophysical Properties. Food Chem. 2019, 288 , 386– 394, DOI: 10.1016/j.foodchem.2019.02.132

[Crossref], [PubMed], [CAS], Google Scholar

196

Purple-fleshed sweet potato acylated anthocyanins: Equilibrium network and photophysical properties

Oliveira, Helder; Basilio, Nuno; Pina, Fernando; Fernandes, Iva; de Freitas, Victor; Mateus, Nuno

Food Chemistry (2019), 288 (), 386-394CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Two anthocyanins from purple-fleshed sweet potato were isolated and characterized by LC-MS and NMR anal. They were identified as peonidin-3-(6'-hydroxybenzoyl)-sophoroside-5-glucoside and peonidin-3-(6'-hydroxybenzoyl-6''-caffeoyl)-sophoroside-5-glucoside. The acid-base dynamics of these acylated anthocyanins was evaluated by means of pH jump techniques. Equil. and kinetic consts. were detd. and, in general, these anthocyanins demonstrated a higher capacity in retaining the red and blue colors at acidic and basic pH values, suggesting a higher resistance to pH variations compared to the parent anthocyanin, peonidin-3-O-glucoside. The presence of acyl groups and addnl. glucoside moieties seems to det. this particular characteristic. The fluorescence properties of these anthocyanins were evaluated. Overall, the species present at higher pH values (7-9) showed higher fluorescence intensity for both anthocyanins, with an optimum λex/λem pair at λex 610 nm/λem 640 nm. The fluorescence characteristics of these anthocyanins were used to evaluate their location in gastric and intestinal cells by fluorescence microscopy.

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197

McClelland, R. A. ; McGall, G. H. Hydration of the Flvylium Ion.2. The 4'-Hydroxyflavylium Ion. J. Org. Chem. 1982, 47 , 3730– 3736, DOI: 10.1021/jo00140a027

[ACS Full Text ], [CAS], Google Scholar

197

Hydration of the flavylium ion. 2. The 4'-hydroxyflavylium ion

McClelland, Robert A.; McGall, Glenn H.

Journal of Organic Chemistry (1982), 47 (19), 3730-6CODEN: JOCEAH; ISSN:0022-3263.

The reactions of aq. I are examd. A rapid initial deprotonation of the OH group occurs, resulting in an anhydro base II; the pKa of this ionization is 5.5. A slower reaction follows in which further equilibration occurs with a pseudobase III and cis-o-(p-HOC6H4COCH:CH)C6H4OH (cis-IV). The stabilities of the neutral species are very similar, the mixt. at equil. consisting of 37% III, 33% cis-IV, and 30% II. This equil. is displaced towards cis-IV in base due to the ionization of its phenolic hydroxyl groups. III is formed in solns. with pH <8 by hydration of I; in solns. with pH >8 direct hydration of II occurs. In all solns. with pH >4 a very slow further reaction occurs resulting in the irreversible formation of trans-IV, the product of thermodn. control at all pH's.

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198

Pina, F. Anthocyanins and Related Compounds. Detecting the Change of Regime between Rate Control by Hydration or by Tautomerization. Dyes Pigm. 2014, 102 , 308– 314, DOI: 10.1016/j.dyepig.2013.10.033

[Crossref], [CAS], Google Scholar

198

Anthocyanins and related compounds. Detecting the change of regime between rate control by hydration or by tautomerization

Pina, Fernando

Dyes and Pigments (2014), 102 (), 308-314CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The network of chem. reactions involving anthocyanins and related compds. has been historically considered as the chem. transformations taking place when the flavylium cation (which is generally stable only in very acidic solns.) disappears upon a pH jump to higher pH values (direct pH jump). In this work profit is taken from the appearance of flavylium cation from equilibrated solns. at moderately acid pH values, (reverse pH jumps) as well as upon irradn. of trans-chalcone in the cases where photochem. is available. Reverse pH jumps, flash photolysis and reaction quantum yields unequivocally show that at sufficiently acidic pH values the tautomerization becomes the rate detg. step of flavylium cation formation. This is a lucky situation since gives kinetic information about tautomerization, the most difficult process to access in the anthocyanins and related compds. network of chem. reactions. The thermodn. and kinetic details of flavylium base photochromic systems are described. Math. expressions for direct and reverse pH jumps, stopped flow and flash photolysis are presented as well as the procedure to obtain all of the rate and equil. consts. of the system.

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199

Mistry, T. V. ; Cai, Y. ; Lilley, T. H. ; Haslam, E. Polyphenol Interactions 0.5. Anthocyanin Copigmentation. J. Chem. Soc., Perkin Trans. 2 1991, 1287– 1296, DOI: 10.1039/p29910001287

[Crossref], [CAS], Google Scholar

199

Polyphenol interactions. Part 5. Anthocyanin copigmentation

Mistry, Tarankumar V.; Cai, Ya; Lilley, Terence H.; Haslam, Edwin

Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1972-1999) (1991), (8), 1287-96CODEN: JCPKBH; ISSN:0300-9580.

In aq. media, anthocyanins undergo several structural transformations and exist in a series of equil. between carbinol-base, flavylium cation, quinonoidal anhydro-base and chalcone forms. A detailed interpretation of the 1H-NMR (400 MHz) spectra of malvin in D2O is given for the first time in the context of these equil. The phenomenon of copigmentation is reviewed and the efficacy of various phenolic flavonoids, galloyl and hexahydroxycinnamyl esters as natural copigments is detd. quant. DNA, RNA and ATP also act as effective copigments for malvin in the form the flavylium ion but both caffeine and theophylline preferentially stabilize the quinonoidal-base forms of the anthocyanin. At pH 3.5 to 7.0, they give rise to stable violet through to blue and finally green colors. 1H-NMR studies of all these intermol. copigmentation reactions are reported and the phenomenon is provisionally interpreted in terms of hydrophobically reinforced π-π stacking of anthocyanin and copigment mols. in the aq. environment.

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200

Houbiers, C. ; Lima, J. C. ; Macanita, A. L. ; Santos, H. Color Stabilization of Malvidin 3-Glucoside: Self-Aggregation of the Flavylium Cation and Copigmentation with the Z-Chalcone Form. J. Phys. Chem. B 1998, 102 , 3578– 3585, DOI: 10.1021/jp972320j

[ACS Full Text ], [CAS], Google Scholar

200

Color Stabilization of Malvidin 3-Glucoside: Self-Aggregation of the Flavylium Cation and Copigmentation with the Z-Chalcone Form

Houbiers, Chantal; Lima, Joao C.; Macanita, Antonio L.; Santos, Helena

Journal of Physical Chemistry B (1998), 102 (18), 3578-3585CODEN: JPCBFK; ISSN:1089-5647. (American Chemical Society)

1H NMR spectroscopy was used to characterize the aggregation processes leading to color stabilization of the natural anthocyanin, malvidin 3-glucoside. The concns. of the different forms in aq. soln. were detd. as a function of pH for several values of the total anthocyanin concn. The chem. shifts were measured as a function of total concn. and temp., and the concn. dependence of the T1 values of relevant resonances were detd. for different concns. and pH values. The data are in agreement with a model that considers the occurrence of multimeric aggregates of flavylium cations at very acidic pH and copigmentation of flavylium cations with the Z-chalcone form at moderately acidic pH. The following equil. consts. were detd.: Kh = 0.0016 M for the flavylium cation hydration, KT = 0.26 for the hemiacetal/E-chalcone tautomerism, Ki = 0.6 for the E-chalcone/Z-chalcone isomerization, K = 3700 M-1 for the flavylium cation self-aggregation, and K' = 3080 M-1 for the flavylium cation/Z-chalcone copigmentation. The relevance of these results for color enhancement is discussed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXivV2rsbo%253D&md5=b79a4324afebeb696b56b2eff491032d

201

Kallam, K. ; Appelhagen, I. ; Luo, J. ; Albert, N. ; Zhang, H. ; Deroles, S. ; Hill, L. ; Findlay, K. ; Andersen, Ø. M. ; Davies, K. Aromatic Decoration Determines the Formation of Anthocyanic Vacuolar Inclusions. Curr. Biol. 2017, 27 , 945– 957, DOI: 10.1016/j.cub.2017.02.027

[Crossref], [PubMed], [CAS], Google Scholar

201

Aromatic Decoration Determines the Formation of Anthocyanic Vacuolar Inclusions

Kallam, Kalyani; Appelhagen, Ingo; Luo, Jie; Albert, Nick; Zhang, Huaibi; Deroles, Simon; Hill, Lionel; Findlay, Kim; Andersen, Oeyvind M.; Davies, Kevin; Martin, Cathie

Current Biology (2017), 27 (7), 945-957CODEN: CUBLE2; ISSN:0960-9822. (Cell Press)

Anthocyanins are some of the most widely occurring secondary metabolites in plants, responsible for the orange, red, purple, and blue colors of flowers and fruits and red colors of autumn leaves. These pigments accumulate in vacuoles, and their color is influenced by chem. decorations, vacuolar pH, the presence of copigments, and metal ions. Anthocyanins are usually sol. in the vacuole, but in some plants, they accumulate as discrete sub-vacuolar structures. Studies have distinguished intensely colored intra-vacuolar bodies obsd. in the cells of highly colored tissues, termed anthocyanic vacuolar inclusions (AVIs), from more globular, membrane-bound anthocyanoplasts. We describe a system in tobacco that adds addnl. decorations to the basic anthocyanin, cyanidin 3-O-rutinoside, normally formed by this species. Using this system, we have been able to establish which decorations underpin the formation of AVIs, the conditions promoting AVI formation, and, consequently, the mechanism by which they form.

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202

Francis, F. J. ; Markakis, P. C. Food Colorants: Anthocyanins. Crit. Rev. Food Sci. Nutr. 1989, 28 , 273, DOI: 10.1080/10408398909527503

[Crossref], [PubMed], [CAS], Google Scholar

202

Food colorants: anthocyanins

Francis, F. J.

Critical Reviews in Food Science and Nutrition (1989), 28 (4), 273-314CODEN: CRFND6; ISSN:0099-0248.

A review, with 429 refs., on the use of anthocyanin pigments as food colorants.

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203

Jurd, L. Acid Fruit and Vegetable Food and Method of Coloring Emplying Benzopyrylium Compounds. US Patent 3,301,683, January 31, 1967.

204

[Crossref], [CAS], Google Scholar

204

Synthetic dyes: simple and original ways to 4-substituted flavylium salts and their corresponding vitisin derivatives

Roehri-Stoeckel, Christine; Gonzalez, Emmanuel; Fougerousse, Andre; Brouillard, Raymond

Canadian Journal of Chemistry (2001), 79 (7), 1173-1178CODEN: CJCHAG; ISSN:0008-4042. (National Research Council of Canada)

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205

Duenas, M. ; Salas, E. ; Cheynier, V. ; Dangles, O. ; Fulcrand, H. Uv-Visible Spectroscopic Investigation of the 8,8-Methylmethine Catechin-Malvidin 3-Glucoside Pigments in Aqueous Solution: Structural Transformations and Molecular Complexation with Chlorogenic Acid. J. Agric. Food Chem. 2006, 54 , 189– 196, DOI: 10.1021/jf0516989

[ACS Full Text ], [CAS], Google Scholar

205

UV-Visible Spectroscopic Investigation of the 8,8-Methylmethine Catechin-malvidin 3-Glucoside Pigments in Aqueous Solution: Structural Transformations and Molecular Complexation with Chlorogenic Acid

Duenas, Montserrat; Salas, Erika; Cheynier, Veronique; Dangles, Olivier; Fulcrand, Helene

Journal of Agricultural and Food Chemistry (2006), 54 (1), 189-196CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The physicochem. properties of 8,8-methylmethine catechin-malvidin 3-O-glucoside isomers [commonly referred to as catechin-ethyl-malvidin 3-O-glucoside (I)] was studied in aq. solns. and compared with those of the parent anthocyanin [malvidin 3-O-glucoside (II)]. The hydration and acidity consts. (pKh and pKa) of the I and II were detd. by UV-visible spectroscopic measurements. I present higher stability toward hydration than II. The high resistance of these ethyl-linked pigments toward the hydration is related to the self-assocn. that offers optimal protection from the nucleophilic attack of water. Moreover, the Et link may confer to the mol. enough flexibility to undergo intramol. interaction, further protecting it from hydration and bisulfite discoloration. In the wine pH range (3.2-4.0), due to the low pKa and high pKh values, the ethyl-linked pigments are present as colored forms (flavylium cation and quinonoid bases).

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206

Melo, M. J. ; Sousa, M. ; Parola, A. J. ; de Melo, J. S. S. ; Catarino, F. ; Marcalo, J. ; Pina, F. Identification of 7,4 '-Dihydroxy-5-Methoxyflavylium in ″Dragon's Blood″: To Be or Not to Be an Anthocyanin. Chem. - Eur. J. 2007, 13 , 1417– 1422, DOI: 10.1002/chem.200600837

[Crossref], [PubMed], [CAS], Google Scholar

206

Identification of 7,4'-dihydroxy-5-methoxyflavylium in "dragon's blood": to be or not to be an anthocyanin

Melo, Maria J.; Sousa, Micaela; Parola, A. Jorge; Seixas de Melo, J. Sergio; Catarino, Fernando; Marcalo, Joaquim; Pina, Fernando

Chemistry - A European Journal (2007), 13 (5), 1417-1422CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

The compd. 7,4'-dihydroxy-5-methoxyflavylium (dracoflavylium, I) was identified as the major red colorant in samples of the "dragon's blood" resin extd. from the Dracaena draco tree. The complex network of reversible chem. reactions that dracoflavylium undergoes in aq. soln. is fully described; for the first time, all the equil. consts. that enable a complete characterization of the system have been obtained (K'a = 1.6 × 10-4, Ka1 = 1.0 × 10-4, Ka2 = 3.2 × 10-8, KCt1 = 1.0 × 10-7, KCt2 = 1.3 × 10-10). Te red color is due to a stable quinoid base, A, which is the major species at pH 4-7. This compd. does not fit the commonly accepted definitions of anthocyanidin and 3-deoxyanthocyanidin. Similar to synthetic flavylium salts, the natural compd. 7,4'-dihydroxy-5-methoxyflavylium gives rise to several species (multistate system) reversibly interconverted by external stimuli such as pH.

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207

Olaniyi, A. A. ; Powell, J. W. ; Whalley, W. B. Pigments of Dragons-Blood Resin.7. Synthesis of (±)-Draconol, (±)-O-Methyldraconol, (±)-O-Methylisodraconol and Derivatives - Structure of Dracorubin. J. Chem. Soc., Perkin Trans. 1 1973, 179– 184, DOI: 10.1039/P19730000179

[Crossref], [CAS], Google Scholar

207

Pigments of dragon's blood resin. VII. Synthesis of (+-)-draconol, (+-)-O-methyldraconal, (+-)-O-methylisodraconol, and derivatives. Structure of dracorubin

Olaniyi, A. A.; Powell, J. W.; Whalley, W. B.

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) (1973), (2), 179-84CODEN: JCPRB4; ISSN:0300-922X.

Condensation of 7-hydroxy-5-methoxyflavan (I) with 4,6-dihydroxy-2-methoxy-3-methylbenzoic acid gave 2,4-dihydroxy-6-methoxy-5-methylphenyl 7-hydroxy-5-methoxy-8-flavanyl ketone, cyclization of which gave (±)-draconol (II, R = Me, R1 = R2 = H). (±)-O-methyldraconol (II, R1 = H, R = R2 = Me) and (±)-O-methylisodraconol (II, R = H, R1 = R2 = Me) were similarly prepd. The structure of dracorubin was thus detd. as III. Oxidative coupling of I with 7-hydroxy-6(and 8)-methylflavylium chloride gave 4-(7-hydroxy-5-methoxy-8-flavanyl)-6-(and 8)-methyl-2-phenylbenzopyran-7-one.

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208

Agbakwuru, E. O. P. ; Whalley, W. B. Pigments of Drgoon's Blood Resin.8. Synthesis of (+or-)-Dracorubin and of (+or-)-Nordracorubin. J. Chem. Soc., Perkin Trans. 1 1976, 1392– 1394, DOI: 10.1039/P19760001392

[Crossref], [CAS], Google Scholar

208

The pigments of 'dragon's blood' resin. Part VIII. Synthesis of (±)-dracorubin and of (±)-nordracorubin

Agbakwuru, Evans O. P.; Whalley, W. Basil

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) (1976), (13), 1392-4CODEN: JCPRB4; ISSN:0300-922X.

Condensation of the carbocations formed on dissoln. of the flavanols I (R = Me, H) in AcOH with 7-hydroxy-5-methoxyflavan gave the dimeric flavans II which on acetylation, debenzylation, oxidn., and base-catalyzed cyclization gave (±)-dracorubin and (±)-nordracorubin III (R = Me, H, resp.).

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209

CameiradosSantos, P. J. ; Brillouet, J. M. ; Cheynier, V. ; Moutounet, M. Detection and Partial Characterisation of New Anthocyanin-Derived Pigments in Wine. J. Sci. Food Agric. 1996, 70 , 204– 208, DOI: 10.1002/(SICI)1097-0010(199602)70:2<204::AID-JSFA484>3.0.CO;2-F

210

Fulcrand, H. ; dos Santos, P. J. C. ; Sarni Manchado, P. ; Cheynier, V. ; Favre Bonvin, J. Structure of New Anthocyanin-Derived Wine Pigments. J. Chem. Soc., Perkin Trans. 1 1996, 735– 739, DOI: 10.1039/p19960000735

[Crossref], [CAS], Google Scholar

210

Structure of new anthocyanin-derived wine pigments

Fulcrand, Helene; Cameira dos Santos, Paulo-Jorge; Sarni-Manchado, Pascale; Cheynier, Veronique; Favre-Bonvin, Jean

Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1996), (7), 735-9CODEN: JCPRB4; ISSN:0300-922X. (Royal Society of Chemistry)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xit1Oktrw%253D&md5=3f28fe97ad9cc51b50b347146143b94c

211

[ACS Full Text ], [CAS], Google Scholar

211

Isolation, Identification, and Characterization of New Color-Stable Anthocyanins Occurring in Some Red Wines

Bakker, Johanna; Timberlake, Colin F.

Journal of Agricultural and Food Chemistry (1997), 45 (1), 35-43CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXitVKjug%253D%253D&md5=a389a2b307de10edebae20e5ce014c92

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Chassaing, S. ; Isorez, G. ; Kueny-Stotz, M. ; Brouillard, R. En Route to Color-Stable Pyranoflavylium Pigments - a Systematic Study of the Reaction between 5-Hydroxy-4-Methylflavylium Salts and Aldehydes. Tetrahedron Lett. 2008, 49 , 6999– 7004, DOI: 10.1016/j.tetlet.2008.09.139

[Crossref], [CAS], Google Scholar

212

En route to color-stable pyranoflavylium pigments - a systematic study of the reaction between 5-hydroxy-4-methylflavylium salts and aldehydes

Chassaing, Stefan; Isorez, Geraldine; Kueny-Stotz, Marie; Brouillard, Raymond

Tetrahedron Letters (2008), 49 (49), 6999-7004CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

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213

Chassaing, S. ; Isorez-Mahler, G. ; Kueny-Stotz, M. ; Brouillard, R. Aged Red Wine Pigments as a Source of Inspiration for Organic Synthesis the Cases of the Color-Stable Pyranoflavylium and Flavylium-(4 -> 8)-Flavan Chrornophores. Tetrahedron 2015, 71 , 3066– 3078, DOI: 10.1016/j.tet.2014.10.058

[Crossref], [CAS], Google Scholar

213

Aged red wine pigments as a source of inspiration for organic synthesis-the cases of the color-stable pyranoflavylium and flavylium-(4→8)-flavan chromophores

Chassaing, Stefan; Isorez-Mahler, Geraldine; Kueny-Stotz, Marie; Brouillard, Raymond

Tetrahedron (2015), 71 (20), 3066-3078CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFWis73K&md5=7d2eb10882585ba040692c92726a660d

214

Oliveira, J. ; Araújo, P. ; Fernandes, A. ; Brás, N. F. ; Mateus, N. ; Pina, F. ; de Freitas, V. Influence of the Structural Features of Amino-Based Pyranoanthocyanins on Their Acid-Base Equilibria in Aqueous Solutions. Dyes Pigm. 2017, 141 , 479– 486, DOI: 10.1016/j.dyepig.2017.03.005

[Crossref], [CAS], Google Scholar

214

Influence of the structural features of amino-based pyranoanthocyanins on their acid-base equilibria in aqueous solutions

Oliveira, Joana; Araujo, Paula; Fernandes, Ana; Bras, Natercia F.; Mateus, Nuno; Pina, Fernando; de Freitas, Victor

Dyes and Pigments (2017), 141 (), 479-486CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The equil. forms of three different families of dimethylamino-based pyranoanthocyanins (1, 2 and 3) were studied in aq. solns. at different pH values from 1 to 12 using UV-Visible spectroscopy. The forms present under those conditions are strongly correlated to the pyranoanthocyanin structural features. The increase of the electronic delocalization helps the protonation at the amino group. At very acidic pH condition (pH < 0) the protonation at the amino group is obsd. for the three pigments, but under less acidic conditions (pH∼1) it only occurs for pigment 3 (pKa1 = 2.4 ± 0.1) and at a lesser extent for pigment 2 (pKa1 = 1.1 ± 0.1). At the same time, the increase of the electronic delocalization on the amino-based pigments also favors the deprotonation at the hydroxyl group present at carbon C-7 yielding the neutral quinoidal base (pKa2 = 2.7 ± 0.1, pKa2 = 4.8 ± 0.1 and pKa2 = 5.4 ± 0.1 for pigment 3, 2 and 1, resp.). For pigment 3, the max. molar fraction obtained for the pyranoflavylium cation form is ∼0.4 due to the proximity of the two acid-base consts. (pKa1 and pKa2) which indicates that at the pH range 1-5 three forms of the compd. are present in equil. (pyranoflavylium dication, pyranoflavylium cation and neutral quinoidal base). The second deprotonation at the 4'-OH was less affected by the structural features of the pigment with the ionization const. situated at pKa3∼9 (pKa3 = 9.5 ± 0.1, pKa3 = 8.9 ± 0.1 and pKa3 = 9.8 ± 0.1 for pigment 1, 2 and 3, resp.).

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Silva, C. P. ; Silva, G. T. M. ; Costa, T. D. ; Carneiro, V. M. T. ; Siddique, F. ; Aquino, A. J. A. ; Freitas, A. A. ; Clark, J. A. ; Espinoza, E. M. ; Vullev, V. I. Chromophores Inspired by the Colors of Fruit, Flowers and Wine. Pure Appl. Chem. 2020, 92 , 255– 263, DOI: 10.1515/pac-2019-0226

[Crossref], [CAS], Google Scholar

215

Chromophores inspired by the colors of fruit, flowers and wine

Silva, Cassio P.; Silva, Gustavo T. M.; Costa, Tassia de Sousa; Carneiro, Vania M. T.; Siddique, Farhan; Aquino, Adelia J. A.; Freitas, Adilson A.; Clark, John A.; Espinoza, Eli M.; Vullev, Valentine I.; Quina, Frank H.

Pure and Applied Chemistry (2020), 92 (2), 255-263CODEN: PACHAS; ISSN:0033-4545. (Walter de Gruyter, Inc.)

Anthocyanins, which are responsible for most of the red, blue and purple colors of fruits and flowers, are very efficient at absorbing and dissipating light energy via excited state proton transfer or charge-transfer mediated internal conversion without appreciable excited triplet state formation. During the maturation of red wines, grape anthocyanins are slowly transformed into pyranoanthocyanins, which have a much more chem. stable pyranoflavylium cation chromophore. Development of straightforward synthetic routes to mono- and disubstituted derivs. of the pyranoflavylium cation chromophore has stimulated theor. and exptl. studies that highlight the interesting absorption and emission properties and redox properties of pyranoflavylium cations. Thus, p-methoxyphenyl substitution enhances the fluorescence quantum yield, while a p-dimethylaminophenyl substituent results in fast decay via a twisted intramol. charge-transfer (TICT) state. Unlike anthocyanins and their synthetic analogs (flavylium cations), a variety of pyranoflavylium cations form readily detectable excited triplet states that sensitize singlet oxygen formation in soln. and exhibit appreciable two-photon absorption cross sections for near-IR light, suggesting a potential for applications in photodynamic therapy. These excited triplet states have microsecond lifetimes in soln. and excited state redn. potentials of at least 1.3 V vs. SCE, features that are clearly desirable in a triplet photoredox catalyst.

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216

Quijada-Morin, N. ; Dangles, O. ; Rivas-Gonzalo, J. C. ; Escribano-Bailon, M. T. Physico-Chemical and Chromatic Characterization of Malvidin 3-Glucoside-Vinylcatechol and Malvidin 3-Glucoside-Vinylguaiacol Wine Pigments. J. Agric. Food Chem. 2010, 58 , 9744– 9752, DOI: 10.1021/jf102238v

[ACS Full Text ], [CAS], Google Scholar

216

Physico-Chemical and Chromatic Characterization of Malvidin 3-Glucoside-vinylcatechol and Malvidin 3-Glucoside-vinylguaiacol Wine Pigments

Quijada-Morin, Natalia; Dangles, Olivier; Rivas-Gonzalo, Julian C.; Escribano-Bailon, M. Teresa

Journal of Agricultural and Food Chemistry (2010), 58 (17), 9744-9752CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The physicochem. and chromatic features of malvidin 3-glucoside-vinylcatechol (PA1) and malvidin 3-glucoside-vinylguaiacol (PA2) adducts were investigated. Important differences between both pigments were obsd. In the investigated pH range (2.0-4.5), the results suggest that PA1 could be considered as a noncovalent dimer of two pyranoflavylium ions (AH)2 which undergo a hydration reaction in two successive steps, with no proton transfer. In contrast, only proton transfer equil. between the pyranoflavylium ion and the quinonoid bases was obsd. for PA2. The hydration and acidity thermodn. consts. of both pyranoanthocyanins were detd. by UV-vis spectroscopy. Pigment PA1 was shown to be less sensitive to bisulfite addn. than to water addn., and PA2 seems to be largely insensitive to both water and bisulfite addns. The binding consts. for the interaction between the pigments and (+)-catechin in aq. soln. and the changes in the CIELAB parameters that it provoked were also detd. The huge increase in the absorption of the pyranoflavylium ion of PA2 when it binds catechin has no equiv. for anthocyanins and nicely outlines the potential of pyranoanthocyanins in the expression of natural colors.

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217

[Crossref], [CAS], Google Scholar

217

Pyranoanthocyanins - an overview on structures, occurrence, and pathways of formation

Rentzsch, Michael; Schwarz, Michael; Winterhalter, Peter

Trends in Food Science & Technology (2007), 18 (10), 526-534CODEN: TFTEEH; ISSN:0924-2244. (Elsevier Ltd.)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVCitrzO&md5=52138471d058a227492e17616a639592

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De Freitas, V. ; Mateus, N. Formation of Pyranoanthocyanins in Red Wines: A New and Diverse Class of Anthocyanin Derivatives. Anal. Bioanal. Chem. 2011, 401 , 1463– 1473, DOI: 10.1007/s00216-010-4479-9

[Crossref], [PubMed], [CAS], Google Scholar

218

Formation of pyranoanthocyanins in red wines: a new and diverse class of anthocyanin derivatives

de Freitas Victor; Mateus Nuno

Analytical and bioanalytical chemistry (2011), 401 (5), 1463-73 ISSN:.

Pyranoanthocyanins constitute one of the most important classes of anthocyanin-derived pigments occurring naturally in red wine. Nonetheless, correct assignment of their structures and pathways of formation in red wine has been relatively recent--less than two decades. Study of these newly discovered pigments is progressively unfolding the chemical pathways that drive the evolution of red wine colour during ageing. The objective of this paper is to review current knowledge regarding the pathway of formation in red wine of a great variety of pyranoanthocyanin structures, namely carboxypyranoanthocyanins, methylpyranoanthocyanins, pyranoanthocyanin-flavanols, pyranoanthocyanin-phenols, portisins, oxovitisins, and pyranoanthocyanin dimers. The chromatic features of some of the compounds, for example their colour expression and acid-base equilibria in aqueous media, are also discussed.

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Cruz, L. ; Petrov, V. ; Teixeira, N. ; Mateus, N. ; Pina, F. ; De Freitas, V. Establishment of the Chemical Equilibria of Different Types of Pyranoanthocyanins in Aqueous Solutions: Evidence for the Formation of Aggregation in Pyranomalvidin-3-O-Coumaroylglucoside-(+)-Catechin. J. Phys. Chem. B 2010, 114 , 13232– 13240, DOI: 10.1021/jp1045673

[ACS Full Text ], [CAS], Google Scholar

219

Establishment of the Chemical Equilibria of Different Types of Pyranoanthocyanins in Aqueous Solutions: Evidence for the Formation of Aggregation in Pyranomalvidin-3-O-coumaroylglucoside-(+)-catechin

Cruz, Luis; Petrov, Vesselin; Teixeira, Natercia; Mateus, Nuno; Pina, Fernando; de Freitas, Victor

Journal of Physical Chemistry B (2010), 114 (41), 13232-13240CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)

The chem. equil. of the pyranomalvidin-3-glucosides linked to (+)-catechin, (-)-epicatechin, and catechol moieties (and the resp. coumaroylglucoside compds.) were established by means of UV-vis spectroscopy. The conjugated double bonds among pyranic rings C and D provide a higher electronic delocalization that prevents the nucleophilic attack of water at position 2. Consequently, besides flavylium cation (AH+), the bases A, A-, and A2- have been identified by increasing pH, and the resp. acidity consts. were detd. by spectrophotometry. The formation of dimers at higher concn. was obsd. for pyranomalvidin-3-O-coumaroylglucoside-(+)-catechin, and the resp. data treated by the exciton model suggests the formation of a dimer where the monomers form J-type aggregates with the dipolar moments in opposite directions and rotated by 174° at a distance of 5.2 Å (from the center).

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Oliveira, J. ; Mateus, N. ; De Freitas, V. Previous and Recent Advances in Pyranoanthocyanins Equilibria in Aqueous Solution. Dyes Pigm. 2014, 100 , 190– 200, DOI: 10.1016/j.dyepig.2013.09.009

[Crossref], [CAS], Google Scholar

220

Previous and recent advances in pyranoanthocyanins equilibria in aqueous solution

Oliveira, Joana; Mateus, Nuno; de Freitas, Victor

Dyes and Pigments (2014), 100 (), 190-200CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

A review. Pyranoanthocyanins are anthocyanin-derived compds. found that present a vast palette of colors ranging from yellow to turquoise blue. Studies in aq. solns. of these pigments by UV-Visible spectroscopy revealed their higher color stability when compared to their anthocyanin precursors. Through NMR techniques it was possible to confirm the absence of hydration reactions in pyranoanthocyanins, contrarily to anthocyanins, which helps explaining their higher color stability with the increase of the pH.

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Gomez-Alonso, S. ; Blanco-Vega, D. ; Gomez, M. ; Hermosin-Gutierrez, I. Synthesis, Isolation, Structure Elucidation, and Color Properties of 10-Acetyl-Pyranoanthocyanins. J. Agric. Food Chem. 2012, 60 , 12210– 12223, DOI: 10.1021/jf303854u

[ACS Full Text ], [CAS], Google Scholar

221

Synthesis, isolation, structure elucidation, and color properties of 10-acetyl-pyranoanthocyanins

Gomez-Alonso, Sergio; Blanco-Vega, Dora; Gomez, M. Victoria; Hermosin-Gutierrez, Isidro

Journal of Agricultural and Food Chemistry (2012), 60 (49), 12210-12223CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Grape anthocyanins reacted with diacetyl (secondary microbial metabolite in winemaking) to form 10-acetylpyranoanthocyanins, a type of anthocyanin pigments similar to other vitisin-type pyranoanthocyanins found in red wines. The 10-acetylpyranomalvidin-3-β-O-glucoside and 10-acetylpyranopeonidin-3-β-O-glucoside were synthesized and their structures were confirmed by UV-VIS, MS/MS, and NMR spectroscopic methods. The synthesis used reaction of diacetyl with malvidin-3-glucoside or peonidin-3-glucoside in aq. acidic medium pH 2.5 at 35°C; the products were isolated using Amberlite XAD-7 chromatog. column. In contrast to other vitisin-type pyranoanthocyanins, these 10-acetylpyranoanthocyanins had differentiated color-related properties. They had an important tendency to occur as colorless hemiacetals at C-10 under wine pH conditions, while co-occurrence of flavylium cation and quinoidal base yielded a broad visible absorbance band around 510-520 nm. They also easily reacted with bisulfite in acidic aq. soln. (pH 2.0), but the expected bleaching was not obsd. The bisulfite was bound to the carbonyl of 10-acetyl substituent instead of the expected C-10 position of the pyranoanthocyanin core, thus giving rise to a red pigment hypsochromically shifted toward orange nuances with max. absorbances at 487-491 nm.

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Mazza, G. ; Brouillard, R. Color Stability and Structural Transformations of Cyanidin 3,5-Diglucoside and Four 3-Deoxyanthocyanins in Aqueous Solutions. J. Agric. Food Chem. 1987, 35 , 422– 426, DOI: 10.1021/jf00075a034

[ACS Full Text ], [CAS], Google Scholar

222

Color stability and structural transformations of cyanidin 3,5-diglucoside and four 3-deoxyanthocyanins in aqueous solutions

Mazza, G.; Brouillard, Raymond

Journal of Agricultural and Food Chemistry (1987), 35 (3), 422-6CODEN: JAFCAU; ISSN:0021-8561.

The acidity consts. together with the equil. distribution of the flavylium cation (AH+), quinoidal base (A), carbinol pseudobase (B), and chalcone (C) of cyanidin 3,5-diglucoside [2611-67-8] and four related 3-deoxyflavylium salts in water at 25° were detd. by the pH-jump method. For cyanidin 3,5-diglucoside, the equil. consts. for the acid-base, hydration, and tautomeric equil. were 4.36 × 10-4 M (pKa' 3.38), 5.85 × 10-3 M (pKh' 2.23) and 0.16, resp. The acidity const. for the chalcone formation reaction starting from the flavylium cation of cyanin was 9.54 × 10-4 M (pKc' 3.02). Thus, in acidic aq. media and at 25°, the most favored species for this anthocyanin is the colorless carbinol pseudobase. 4'-Hydroxy- [4134-79-6], 4-methyl-7-hydroxy- [20921-29-3], and 4'-methoxy-4-carboxyl-7-hydroxyflavylium chloride [107616-79-5] were essentially stable in the form of flavylium cation in fast equil. with the quinoidal base. Apigeninidin existed primarily in the flavylium cationic form at pH ≤4 and as a mixt. of the three neutral forms at higher pH. Unlike the common anthocyanin, then, the 3-deoxyflavylium salts could be of advantage to color foods and beverages at neutral pH.

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223

[ACS Full Text ], [CAS], Google Scholar

223

Chemical Behavior of Methylpyranomalvidin-3-O-glucoside in Aqueous Solution Studied by NMR and UV-Visible Spectroscopy

Oliveira, Joana; Petrov, Vesselin; Parola, A. Jorge; Pina, Fernando; Azevedo, Joana; Teixeira, Natercia; Bras, Natercia F.; Fernandes, Pedro A.; Mateus, Nuno; Ramos, Maria Joao; de Freitas, Victor

Journal of Physical Chemistry B (2011), 115 (6), 1538-1545CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXoslymuw%253D%253D&md5=c268a5c3cb31286aa18c9e8843cd1741

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Vallverdu-Queralt, A. ; Biler, M. ; Meudec, E. ; Le Guerneve, C. ; Vernhet, A. ; Mazauric, J. P. ; Legras, J. L. ; Loonis, M. ; Trouillas, P. ; Cheynier, V. p-Hydroxyphenyl-Pyranoanthocyanins: An Experimental and Theoretical Investigation of Their Acid-Base Properties and Molecular Interactions. Int. J. Mol. Sci. 2016, 17 , 1842, DOI: 10.3390/ijms17111842

[Crossref], [CAS], Google Scholar

224

p-Hydroxyphenyl-pyranoanthocyanins: an experimental and theoretical investigation of their acid-base properties and molecular interactions

Vallverdu-Queralt, Anna; Biler, Michal; Meudec, Emmanuelle; Le Guerneve, Christine; Vernhet, Aude; Mazauric, Jean-Paul; Legras, Jean-Luc; Loonis, Michele; Trouillas, Patrick; Cheynier, Veronique; Dangles, Olivier

International Journal of Molecular Sciences (2016), 17 (11), 1842/1-1842/19CODEN: IJMCFK; ISSN:1422-0067. (MDPI AG)

The physicochem. properties of the wine pigments catechyl-pyranomalvidin-3-O-glucoside (PA1) and guaiacyl-pyranomalvidin-3-O-glucoside (PA2) are extensively revisited using UV-visible spectroscopy, dynamic light scattering (DLS) and quantum chem. d. functional theory (DFT) calcns. In mildly acidic aq. soln., each cationic pigment undergoes regioselective deprotonation to form a single neutral quinonoid base and water addn. appears negligible. Above pH = 4, both PA1 and PA2 become prone to aggregation, which is manifested by the slow build-up of broad absorption bands at longer wavelengths (λ ≥ 600 nm), followed in the case of PA2 by pptn. Some phenolic copigments are able to inhibit aggregation of pyranoanthocyanins (PAs), although at large copigment/PA molar ratios. Thus, chlorogenic acid can dissoc. PA1 aggregates while catechin is inactive. With PA2, both chlorogenic acid and catechin are able to prevent pptn. but not self-assocn. Calcns. confirmed that the noncovalent dimerization of PAs is stronger with the neutral base than with the cation and also stronger than π-π stacking of PAs to chlorogenic acid (copigmentation). For each type of complex, the most stable conformation could be obtained. Finally, PA1 can also bind hard metal ions such as Al3+ and Fe3+ and the corresponding chelates are less prone to self-assocn.

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Oliveira, J. ; Mateus, N. ; Silva, A. M. S. ; De Freitas, V. Equilibrium Forms of Vitisin B Pigments in an Aqueous System Studied by Nmr and Visible Spectroscopy. J. Phys. Chem. B 2009, 113 , 11352– 11358, DOI: 10.1021/jp904776k

[ACS Full Text ], [CAS], Google Scholar

225

Equilibrium Forms of Vitisin B Pigments in an Aqueous System Studied by NMR and Visible Spectroscopy

Oliveira, Joana; Mateus, Nuno; Silva, Artur M. S.; de Freitas, Victor

Journal of Physical Chemistry B (2009), 113 (32), 11352-11358CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)

The main species in the acid-base equil. of two pyranoanthocyanins (vitisins B), pyranomalvidin-3-glucoside (I) and pyranomalvidin-3-O-coumaroylglucoside (II), and the resp. pKa were detd. using NMR, visible spectroscopy, and mass spectrometry techniques. The three equil. involve protonation of the pyranoflavylium cation of vitisin B (pKa1) and two deprotonations (pKa2 and pKa3). For pigment I, the values obtained through the titrn. curves of the chem. shift of some protons vs. pH were (pKa1 < 0.68; pKa2 = 4.40±0.08; pKa3 = 7.45±0.09) very close to the values obtained by visible spectroscopy (pKa1 < 0.63; pKa2 = 4.43±0.02; pKa3 = 7.34±0.03). For pigment II, it was only possible to calc. the pKa by visible spectroscopy (pKa1 < 0.75; pKa2 = 4.66±0.10; pKa3 = 6.76±0.10). NMR studies have shown that pigment I does not undergo hydration, and the hypothesis of the occurrence of hemiacetal forms in equil. was discarded.

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Oliveira, J. ; Mateus, N. ; de Freitas, V. Network of Carboxypyranomalvidin-3-O-Glucoside (Vitisin a) Equilibrium Forms in Aqueous Solution. Tetrahedron Lett. 2013, 54 , 5106– 5110, DOI: 10.1016/j.tetlet.2013.07.046

[Crossref], [CAS], Google Scholar

226

Network of carboxypyranomalvidin-3-O-glucoside (vitisin A) equilibrium forms in aqueous solution

Oliveira, Joana; Mateus, Nuno; de Freitas, Victor

Tetrahedron Letters (2013), 54 (37), 5106-5110CODEN: TELEAY; ISSN:0040-4039. (Elsevier Ltd.)

The equil. forms of carboxypyranomalvidin-3-O-glucoside (vitisin A) were studied in aq. soln. at different pH values by NMR and UV-Visible spectroscopy. The results obtained revealed three deprotonation reactions at positions 10-COOH, 7-OH and 4'-OH: pKa1 = 1.09 ± 0.09; pKa2 = 4.93 ± 0.02; pKa3 = 9.14 ± 0.05, data obtained from NMR titrn. The titrn. by NMR confirmed the absence of hydration reactions since no characteristic peaks of the hemiketal form were obsd. in the NMR spectrum at any pD value studied (pD 0.67-10.99).

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227

Chakravarty, G. ; Seshadri, T. R. Study of 3,2-Furanoflavylium Chlorides. Indian J. Chem. 1964, 2 , 319– 323

[CAS], Google Scholar

227

3,2'-Furanoflavylium chlorides

Chakravarty, Geeta; Seshadri, T. R.

Indian Journal of Chemistry (1964), 2 (8), 319-23CODEN: IJOCAP; ISSN:0019-5103.

6-Hydroxy- and 6-methoxycoumaranones were condensed with salicylaldehyde, resorcylaldehyde and its mono-Me ether, and phloroglucinaldehyde and its di-Me ether and triacetate, according to the method of Pratt and Robinson (CA 16, 3483) to yield a number of 3,2'-furanoflavylium salts (Ia). Their properties and color reactions closely resembled those of flavylium salts of the gesneridin type, though their spectral characteristics did not; the introduction of the furan ring seemed to have a hypsochromic effect. The furan ring in Ia was stable to treatment with hot aq. Na2CO3. This observation provided support to the dipyran structure of cyanomaclurin (CA 59, 8717f; Nair and Venkataraman, CA 59, 584a). The following Ia were prepd.: 4'-hydroxy-g,2'-furanoflavylium chloride (I), m. 200° (decompn.); Me ether (II) of I, m. 190° (decompn.) [II treated with aq. NaOAc yielded the corresponding chalcone, m. 230° (decompn.)]; and 4',7-dihydroxy-3,2'-furanoflavylium chloride (III), m. >290° (color change at 120°) [pseudoacetate (IV) m. 160°]. III (83 mg.) in 1 ml. EtOH was treated with 3 ml. satd. soln. of NaOAc in H2O, and the mixt. stirred and left 2 days in a refrigerator to yield 50 mg. of the corresponding anhydro color base, m. 240° (decompn.) (EtOAc)]. 4',7-Dimethoxy-3,2'-furanoflavylium chloride, m. 200° (color changed at 160°) [V lost HCl slowly at room temp. to give the corresponding chalcone; treatment of V with aq. NaOAc (as for III) yielded the corresponding chalcone, m. 220° (EtOAc-petr. ether)]; 4',5,7-trihydroxy-3,2'-furanoflavylium chloride (VI), m. 280° (became black) [VI yielded the corresponding color base, m. 220° (EtOAc)]; 5,7-dihydroxy-4'-methoxy-3,2'-furanoflavylium chloride (VII), m. >290° (color changed at 160°) [VII yielded the corresponding anhydro-color base, m. >270° (EtOAc); VII gave a pseudoacetate (VIII), m. 170° (decompn.)]; 5,7-dimethoxy-4'-hydroxy-3,2'-furanoflavylium chloride (IX), m. 170° (decompn.) (HOAc-HCl) [IX yielded the corresponding color base, m. 163-5° (EtOAc)]; 4',5,7-trimethoxy-3,2'-furanoflavylium chloride (X), m. >270° (color change at 120°) (HOAcHCl) [X yielded (NaOAc) the corresponding chalcone (XI), m. 174° (EtOH)]; and 2',4',7-trihydroxyflavylium chloride, m. 290° (decompn.) (MeOH-HCl). Treatment of X with aq. Na2CO3 soln. at 90°, cooling, and acidifying the soln. yielded the corresponding chalcone, m.p. and mixed m.p. 174°, which could be reconverted into VI by boiling with alc. HCl. Similar treatment of VI did not yield any chalcone; VI was recovered. The behavior of Ia in aq. NaOH, Na2CO3, NaHCO3, and EtOH was described. Chromatographic and uv. spectral data were given.

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228

Alejo-Armijo, A. ; Basilio, N. ; Freitas, A. A. ; Macanita, A. L. ; Lima, J. C. ; Parola, A. J. ; Pina, F. Ground and Excited State Properties of Furanoflavylium Derivatives. Phys. Chem. Chem. Phys. 2019, 21 , 21651– 21662, DOI: 10.1039/C9CP04917G

[Crossref], [PubMed], [CAS], Google Scholar

228

Ground and excited state properties of furanoflavylium derivatives

Alejo-Armijo, Alfonso; Basilio, Nuno; Freitas, Adilson A.; Macanita, Antonio L.; Lima, Joao C.; Parola, A. Jorge; Pina, Fernando

Physical Chemistry Chemical Physics (2019), 21 (38), 21651-21662CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)

The comparison of the ground-state reactivity of anthocyanins and aurone model compds. (i.e. with and without the furano bridge) has shown that the kinetic paradigm does not depend on the bridge but only on the hydroxyl substituent pattern, independently of the presence of the bridge: (i) bell shaped kinetics for those with two hydroxyl substituents in position 4' and 7, and (ii) four distinct kinetic steps for the mono substituted compds. with a hydroxyl in position 4'. The excited state proton transfer (ESPT) properties of these compds. were also investigated using steady-state and time-resolved spectroscopic techniques. It was found that the ESPT efficiency is significantly higher for the bridged compds. Interestingly, pH-dependent steady-state fluorescence emission expts. show that in 4',7-dihydroxyfuranoflavylium the hydroxyl group in position 7 is the more acidic one in the excited state, while 1H NMR titrn. curves indicate a higher acidity const. in the ground state for the proton at the hydroxyl group in position 4'. Differently, the fluorescence emission spectrum of the quinoidal base deprotonated at position 7 is only obsd. upon excitation of the flavylium cation while the one from the base deprotonated at 4' is obsd. upon direct excitation.

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229

Berland, H. ; Albert, N. W. ; Stavland, A. ; Jordheim, M. ; McGhie, T. K. ; Zhou, Y. F. ; Zhang, H. B. ; Deroles, S. C. ; Schwinn, K. E. ; Jordan, B. R. Auronidins Are a Previously Unreported Class of Flavonoid Pigments That Challenges When Anthocyanin Biosynthesis Evolved in Plants. Proc. Natl. Acad. Sci. U. S. A. 2019, 116 , 20232– 20239, DOI: 10.1073/pnas.1912741116

[Crossref], [PubMed], [CAS], Google Scholar

229

Auronidins are a previously unreported class of flavonoid pigments that challenges when anthocyanin biosynthesis evolved in plants

Proceedings of the National Academy of Sciences of the United States of America (2019), 116 (40), 20232-20239CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)

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230

Snell, K. R. S. ; Kokubun, T. ; Griffiths, H. ; Convey, P. ; Hodgson, D. A. ; Newsham, K. K. Quantifying the Metabolic Cost to an Antarctic Liverwort of Responding to an Abrupt Increase in Uvb Radiation Exposure. Glob. Chang. Biol. 2009, 15 , 2563– 2573, DOI: 10.1111/j.1365-2486.2009.01929.x

231

Kunz, S. ; Becker, H. Bibenzyl Derivatives from the Liverwort Ricciocarpos Natans. Phytochemistry 1994, 36 , 675– 677, DOI: 10.1016/S0031-9422(00)89795-2

[Crossref], [CAS], Google Scholar

231

Bibenzyl derivatives from the liverwort Ricciocarpos natans

Kunz, Siegmund; Becker, Hans

Phytochemistry (1994), 36 (3), 675-7CODEN: PYTCAS; ISSN:0031-9422.

A new bibenzyl (2,5,4'-trihydroxybibenzyl), a dimeric bisbibenzyl (6',6'''-bis-riccardin C) and a phenylethylcyclohexanone (prelunularin) were isolated from the liverwort Ricciocarpos natans grown in axenic culture. All structures were established on the basis of spectral data and chem. evidence.

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232

Taniguchi, S. ; Yazaki, K. ; Yabu-uchi, R. ; Kawakami, K. ; Ito, H. ; Hatano, T. ; Yoshida, T. Galloylglucoses and Riccionidin a in Rhus Javanica Adventitious Root Cultures. Phytochemistry 2000, 53 , 357– 363, DOI: 10.1016/S0031-9422(99)00399-4

[Crossref], [PubMed], [CAS], Google Scholar

232

Galloylglucoses and riccionidin A in Rhus javanica adventitious root cultures

Taniguchi, Shoko; Yazaki, Kazufumi; Yabu-Uchi, Ryoko; Kawakami, Ken-Ya; Ito, Hideyuki; Hatano, Tsutomu; Yoshida, Takashi

Phytochemistry (2000), 53 (3), 357-363CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science Ltd.)

Adventitious root cultures of Rhus javanica L. produced large amts. of galloylglucoses (gallotannins) and an anthocyanidin, riccionidin A, formerly found only in liverworts. Prodn. of both galloylglucoses and riccionidin A in the adventitious root culture system was suppressed by light. The Rhus root culture showed the highest productivity for those secondary metabolites in a modified Linsmaier-Skoog (LS) liq. medium contg. 30 mM NH4+ and 30 mM NO3- as nitrogen sources in the presence of 10-6 M 3-indoleacetic acid (IAA).

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Dyker, G. ; Bauer, M. Synthesis of 2,3,6,8-Tetrahydroxybenzofuro 3,2-B 1 Benzopyrylium Chloride (Riccionidin a).. J. Prakt. Chem./Chem.-Ztg. 1998, 340 , 271– 273, DOI: 10.1002/prac.19983400312

[Crossref], [CAS], Google Scholar

233

Synthesis of 2,3,6,8-tetrahydroxybenzofuro[3,2-b]benzopyrylium chloride (riccionidin A)

Dyker, Gerald; Bauer, Michael

Journal fuer Praktische Chemie/Chemiker-Zeitung (1998), 340 (3), 271-273CODEN: JPCCEM; ISSN:0941-1216. (Johann Ambrosius Barth)

The liverwort pigment riccionidin A was synthesized in a single preparative step from 2,4,5-(HO)C6H2CHO and the appropriate benzofuranone by a double condensation reaction.

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234

Alejo-Armijo, A. ; Parola, A. J. ; Pina, F. Ph-Dependent Multistate System Generated by a Synthetic Furanoflavylium Compound: An Ancestor of the Anthocyanin Multistate of Chemical Species. ACS Omega 2019, 4 , 4091– 4100, DOI: 10.1021/acsomega.8b03696

[ACS Full Text ], [CAS], Google Scholar

234

pH-Dependent Multistate System Generated by a Synthetic Furanoflavylium Compound: An Ancestor of the Anthocyanin Multistate of Chemical Species

Alejo-Armijo, A.; Parola, A. Jorge; Pina, Fernando

ACS Omega (2019), 4 (2), 4091-4100CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)

The multistate of chem. species generated by 4'-hydroxy-3,2'-furanoflavylium is similar to that of anthocyanins and related compds. This furanoflavylium multistate system was fully characterized by UV-Visible and NMR spectroscopies, allowing detn. of the resp. equil. and rate consts. In contrast with the multistate generated by flavylium cations derived from anthocyanins and related compds., the furanoflavylium multistate is characterized by much slower hydration and tautomerization (pyran ring opening-closure). In addn., the cis-trans isomerization of the chalcones of this system (2'-hydroxyaurones) is extremely slow when compared with anthocyanins. The obsd. similar order of magnitude for tautomerization and isomerization rate consts. leads to a peculiar kinetics from flavylium cation (pH = 1) to the stable trans-chalcones (higher pH values). The hemiketal appears and disappears during the first stages of the kinetics that gives the intermediate cis-chalcone (pseudo-equil.). This last species disappears in a much slower process, as fully characterized by 1H NMR, to give the final trans-chalcone.

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235

Gomes, R. ; Diniz, A. M. ; Jesus, A. ; Parola, A. J. ; Pina, F. The Synthesis and Reaction Network of 2-Styryl-1-Benzopyrylium Salts: An Unexploited Cass of Potential Colorants. Dyes Pigm. 2009, 81 , 69– 79, DOI: 10.1016/j.dyepig.2008.09.007

[Crossref], [CAS], Google Scholar

235

The synthesis and reaction network of 2-styryl-1-benzopyrylium salts: An unexploited class of potential colorants

Gomes, Raquel; Diniz, Ana M.; Jesus, Alexandre; Parola, A. Jorge; Pina, Fernando

Dyes and Pigments (2009), 81 (1), 69-79CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

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236

Pina, F. ; Melo, M. J. ; Parola, A. J. ; Maestri, M. ; Balzani, V. Ph-Controlled Photochromism of Hydroxyflavylium Ions. Chem. - Eur. J. 1998, 4 , 2001– 2007, DOI: 10.1002/(SICI)1521-3765(19981002)4:10<2001::AID-CHEM2001>3.0.CO;2-P

[Crossref], [CAS], Google Scholar

236

pH-controlled photochromism of hydroxyflavylium ions

Pina, Fernando; Melo, Maria Joao; Parola, A. Jorge; Maestri, Mauro; Balzani, Vincenzo

Chemistry - A European Journal (1998), 4 (10), 2001-2007CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH)

The structural transformations and photochromic properties of the 7-hydroxyflavylium ion have been investigated by means of the pH jump technique and continuous and pulsed light excitation. The primary photoproduct of UV irradn. of the colorless trans-chalcone form, which is the predominant species at pH 4, is its colorless cis isomer, which rapidly disappears on a time scale of seconds through two competitive processes: (i) back-reaction to yield the trans-chalcone form, and (ii) formation of the colored flavylium ion and its conjugated quinoidal base. Over minutes or hours (depending on pH), the system reverts quant. to its original state. The rate consts. and equil. consts. of the various processes have been obtained and compared with those previously reported for the 4'-hydroxyflavylium and 4',7-dihydroxyflavylium ions. This comparison demonstrates the substituent effect on the rate and equil. consts.; the effect on the rate const. of the cis→trans thermal isomerization reaction is particularly strong. For the 7-hydroxyflavylium and 4',7-dihydroxyflavylium ions the pH of the soln. plays the role of a tap for the color intensity generated by light excitation. This also means that this system can be viewed as a light-switchable pH indicator.

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237

Felle, H. H. Ph Regulation in Anoxic Plants. Ann. Bot. 2005, 96 , 519– 532, DOI: 10.1093/aob/mci207

[Crossref], [PubMed], [CAS], Google Scholar

237

pH regulation in anoxic plants

Felle, Hubert H.

Annals of Botany (Oxford, United Kingdom) (2005), 96 (4), 519-532CODEN: ANBOA4; ISSN:0305-7364. (Oxford University Press)

A review. PH regulation is the result of a complex interaction of ion transport, H+ buffering, H+-consuming and H+-producing reactions. Cells under anoxia experience an energy crisis; an early response thereof (in most tissues) is a rapid cytoplasmic acidification of roughly half a pH unit. Depending on the degree of anoxia tolerance, this pH remains relatively stable for some time, but then drops further due to an energy shortage, which, in concert with a general breakdown of transmembrane gradients, finally leads to cell death unless the plant finds access to an energy source. In this review the much-debated origin of the initial pH change and its regulation under anoxia is discussed, as well as the problem of how tissues deal with the energy crisis and to what extent pH regulation and membrane transport from and into the vacuole and the apoplast is a part thereof. It is postulated that, because a foremost goal of cells under anoxia must be energy prodn. (having an anaerobic machinery that produces insufficient amts. of ATP), a new pH is set to ensure a proper functioning of the involved enzymes. Thus, the anoxic pH is not experienced as an error signal and is therefore not reversed to the aerobic level. Although acclimated and anoxia-tolerant tissues may display higher cytoplasmic pH than non-acclimated or anoxia-intolerant tissues, evidence for an impeded pH-regulation is missing even in the anoxia-intolerant tissues. For sufficient energy prodn., residual H+ pumping is vital to cope with anoxia by importing energy-rich compds.: however it is not vital for pH-regulation. Whereas the initial acidification is not due to energy shortage, subsequent uncontrolled acidosis occurring in concert with a general gradient breakdown damages the cell but may not be the primary event.

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Echeverria, E. ; Burns, J. ; Felle, H. Compartmentation and Cellular Conditions Controlling Sucrose Breakdown in Mature Acid Lime Fruits. Phytochemistry 1992, 31 , 4091– 4095, DOI: 10.1016/0031-9422(92)80420-J

[Crossref], [CAS], Google Scholar

238

Compartmentation and cellular conditions controlling sucrose breakdown in mature acid lime fruits

Echeverria, Ed; Burns, Jacqueline; Felle, Hubert

Phytochemistry (1992), 31 (12), 4091-5CODEN: PYTCAS; ISSN:0031-9422.

The intracellular conditions required for acid hydrolysis of sucrose in acid lime juice cells were examd. with particular attention to the potential of enzymic sucrose breakdown and the existence of acid invertase inhibitors. The decrease in acid invertase activity during fruit development was not due to the presence of an inhibitor, as measured by subjecting the tissue ext. to treatments known to inactivate the inhibitor. The vacuolar pH of about 2.1 was confirmed by microelectrode detns. using intact vesicle tissue. Addnl., compartmentation studies using the poly-L-lysine method revealed total vacuolar localization of sucrose in mature cells. Thus, conditions necessary for in vivo acid hydroylsis of sucrose, namely a lack of enzymic sucrose breakdown, complete vacuolar sucrose compartmentation and a low vacuolar pH, are concurrently present in mature juice cells of acid limes.

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Figueiredo, P. ; George, F. ; Tatsuzawa, F. ; Toki, K. ; Saito, N. ; Brouillard, R. New Features of Intramolecular Copigmentation by Acylated Anthocyanins. Phytochemistry 1999, 51 , 125– 132, DOI: 10.1016/S0031-9422(98)00685-2

[Crossref], [CAS], Google Scholar

239

New features of intramolecular copigmentation by acylated anthocyanins

Figueiredo, Paulo; George, Florian; Tatsuzawa, Fumi; Toki, Kenjiro; Saito, Norio; Brouillard, Raymond

Phytochemistry (1999), 51 (1), 125-132CODEN: PYTCAS; ISSN:0031-9422. (Elsevier Science Ltd.)

Three series of structurally related anthocyanins, extd. from the red-purple flowers of Dendrobium "Pramot", xLaeliocattleya cv. Mini Purple, Bletilla striata and Phalaenopsis all belonging to the Orchidaceae family and another series extd. from the pink flowers of Senecio cruentus (Compositae) allowed the confirmation of the existence of strong intramol. copigmentation effects. These interactions confer stability to the colored forms of the mols., in a wide range of slightly acidic to neutral aq. media. Moreover, the existence of structural relationships among the four series stressed the different influences exerted by the diverse substituent groups. The existence of a malonylglucoside attached to position 3 of all but three of the mols. put forward a new role for the malonyl residue, in this particular position.

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240

[Crossref], [CAS], Google Scholar

240

Red cabbage anthocyanins: The influence of D-glucose acylation by hydroxycinnamic acids on their structural transformations in acidic to mildly alkaline conditions and on the resulting color

Moloney, Micheal; Robbins, Rebecca J.; Collins, Tom M.; Kondo, Tadao; Yoshida, Kumi; Dangles, Olivier

Dyes and Pigments (2018), 158 (), 342-352CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

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241

Gerard, V. ; Ay, E. ; Morlet-Savary, F. ; Graff, B. ; Galopin, C. ; Ogren, T. ; Mutilangi, W. ; Lalevee, J. Thermal and Photochemical Stability of Anthocyanins from Black Carrot, Grape Juice, and Purple Sweet Potato in Model Beverages in the Presence of Ascorbic Acid. J. Agric. Food Chem. 2019, 67 , 5647– 5660, DOI: 10.1021/acs.jafc.9b01672

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241

Thermal and Photochemical Stability of Anthocyanins from Black Carrot, Grape Juice, and Purple Sweet Potato in Model Beverages in the Presence of Ascorbic Acid

Gerard, Violaine; Ay, Emel; Morlet-Savary, Fabrice; Graff, Bernadette; Galopin, Christophe; Ogren, Thaddao; Mutilangi, William; Lalevee, Jacques

Journal of Agricultural and Food Chemistry (2019), 67 (19), 5647-5660CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Anthocyanins are natural dyes widely used in the food industry, but their chem. stability in beverages can be affected by the presence of additives. In the present paper, the interaction between anthocyanins and ascorbic acid (AA) is more particularly investigated. Ascorbic acid is an ubiquitous component in food products. In this study, the thermal stability at 43°C and the photolysis stability in air and in an inert atm. (N2) of anthocyanins extd. from black carrot (BC), grape juice (GJ), and purple sweet potato (SP) were studied in the presence and absence of ascorbic acid (in citrate buffer at pH 3). Discriminating the main environmental factors (i.e., heat and light) affecting anthocyanin stability is a key point for better understanding the degrdn. pathways. The stability of the anthocyanins was followed by UV-vis spectrometry. Moreover, to understand the degrdn. mechanisms in both the presence and absence of ascorbic acid, various techniques such as fluorescence quenching, cyclic voltammetry, and electron-spin-resonance (ESR) spectroscopy were also used to furnish a full coherent picture of the chem. mechanisms assocd. with the anthocyanin degrdn. In addn., MOs and bond-dissocn. energies (BDE) were calcd. to extend the investigation. Moreover, the effects of some supplementary stabilizers (chlorogenic acid, sinapic acid, tannic acid, fumaric acid, β-carotene, isoquercitrin, myricitrin, green coffee bean ext., and rosemary ext.) and sugars (sucrose, fructose, and glucose) on anthocyanins stability in the presence of ascorbic acid were examd.

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Gras, C. C. ; Nemetz, N. ; Carle, R. ; Schweiggert, R. M. Anthocyanins from Purple Sweet Potato (Ipomoea Batatas (L.) Lam.) and Their Color Modulation by the Addition of Phenolic Acids and Food-Grade Phenolic Plant Extracts. Food Chem. 2017, 235 , 265– 274, DOI: 10.1016/j.foodchem.2017.04.169

[Crossref], [PubMed], [CAS], Google Scholar

242

Anthocyanins from purple sweet potato (Ipomoea batatas (L.) Lam.) and their color modulation by the addition of phenolic acids and food-grade phenolic plant extracts

Gras, Claudia C.; Nemetz, Nicole; Carle, Reinhold; Schweiggert, Ralf M.

Food Chemistry (2017), 235 (), 265-274CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Anthocyanin profiles and contents of three purple sweet potato provenances were investigated by HPLC-DAD-MSn. In contrast to widely uniform profiles, the contents of total (558-2477 mg/100 g DM) and individual anthocyanins varied widely. Furthermore, quant. and qual. effects of intermol. co-pigmentation were studied by adding chlorogenic and rosmarinic acids, and food-grade phenolic apple and rosemary exts. at various dosages to a dild. purple sweet potato conc. at pH 0.9, 2.6, 3.6, and 4.6. Addn. of co-pigments generally increased pKH estimate-values of anthocyanins from 3.28 (without co-pigments) to up to 4.71, thus substantially broadening the pH range wherein colored forms prevail. The most pronounced hyperchromic shift by up to +50.5% at the absorption max. was obsd. at pH 4.6. Simply by blending the co-pigments with purple sweet potato anthocyanins at pH-values ranging from 2.6 to 4.6, purplish-blue, light pink, magenta, brick-red, and intense red hues were accessible as expressed by CIE-L*a*b* color values.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXotVyitLw%253D&md5=fc4c2a9f41648453680035b8ce30edab

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Li, J. ; Li, X. D. ; Zhang, Y. ; Zheng, Z. D. ; Qu, Z. Y. ; Liu, M. ; Zhu, S. H. ; Liu, S. ; Wang, M. ; Qu, L. Identification and Thermal Stability of Purple-Fleshed Sweet Potato Anthocyanins in Aqueous Solutions with Various Ph Values and Fruit Juices. Food Chem. 2013, 136 , 1429– 1434, DOI: 10.1016/j.foodchem.2012.09.054

[Crossref], [PubMed], [CAS], Google Scholar

243

Identification and thermal stability of purple-fleshed sweet potato anthocyanins in aqueous solutions with various pH values and fruit juices

Li, Jie; Li, Xiao-ding; Zhang, Yun; Zheng, Zheng-dong; Qu, Zhi-ya; Liu, Meng; Zhu, Shao-hua; Liu, Shuo; Wang, Meng; Qu, Lu

Food Chemistry (2013), 136 (3-4), 1429-1434CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Thirteen anthocyanins were identified in the purple-fleshed sweet potato cultivar Jihei No. 1. The main anthocyanins were 3-sophoroside-5-glucoside derivs. from cyanidin and peonidin, acylated with p-hydroxybenzoic acid, ferulic acid, or caffeic acid. A unique anthocyanin, delphinidin-3,5-diglucoside was also found. The thermal stability of purple-fleshed sweet potato anthocyanins (PSPAs) followed a first-order kinetics model. Aq. solns. with various pH (2, 3, 4, 5, and 6) and fruit juices (apple, pear, grapefruit, orange, tangerine, kiwifruit, and lemon) were colored with PSPAs. The enrichment and degrdn. kinetics of anthocyanins in these matrixes were investigated at 80, 90, and 100 °C. A higher stability of anthocyanins was obtained in aq. solns. with pH 3 and 4 and in apple and pear juices. Moreover, the activation energies for PSPA degrdn. in aq. solns. with various pH and fruit juices ranged from 66.56 kJ/mol to 111.57 kJ/mol and 46.76 kJ/mol to 75.68 kJ/mol, resp.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhslaktbjF&md5=00fd0ad40f23f1a05f6efeed4fc44af8

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Sigurdson, G. T. ; Robbins, R. J. ; Collins, T. M. ; Giusti, M. M. Molar Absorptivities (Epsilon) and Spectral and Colorimetric Characteristics of Purple Sweet Potato Anthocyanins. Food Chem. 2019, 271 , 497– 504, DOI: 10.1016/j.foodchem.2018.07.096

[Crossref], [PubMed], [CAS], Google Scholar

244

Molar absorptivities (ε) and spectral and colorimetric characteristics of purple sweet potato anthocyanins

Sigurdson, Gregory T.; Robbins, Rebecca J.; Collins, Thomas M.; Giusti, M. Monica

Food Chemistry (2019), 271 (), 497-504CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Purple sweet potato, a source of acylated cyanidin and peonidin derivs., is com. available as a food colorant. Our objectives were to det. molar absorptivities (ε), spectral and colorimetric properties of purple sweet potato anthocyanins. Anthocyanins were isolated by semi-preparative HPLC, weighed, dried, and redissolved in acidic methanol or water. Anthocyanins were dild. at pH 1-9; ε, spectra, and color were measured on the methanolic and aq. solns. Higher ε were obtained in 0.1% HCl methanol (10,797-31,257 L/(mol × cm)) than in aq. soln. pH 1 (8861-24,303 L/(mol × cm)). Peonidin-3-sophoroside-5-glucoside had greatest ε in pH 1, but in alk. pH, ε of acylated Peonidin-3-sophoroside-5-glucoside derivs. were greatest. Generally monoacylation decreased ε while diacylation increased ε. Location of acylation also affected ε of two Peonidin isomers (pH 1: 15,999 and 21,011 L/(mol × cm)). All anthocyanins expressed red-pink hues (330°-13.2°) in acidic pH and blues (230°-262°) in alk. pH.

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Eichhorn, S. ; Winterhalter, P. Anthocyanins from Pigmented Potato (Solanum Tuberosum L.) Varieties. Food Res. Int. 2005, 38 , 943– 948, DOI: 10.1016/j.foodres.2005.03.011

[Crossref], [CAS], Google Scholar

245

Anthocyanins from pigmented potato (Solanum tuberosum L.) varieties

Eichhorn, S.; Winterhalter, P.

Food Research International (2005), 38 (8-9), 943-948CODEN: FORIEU; ISSN:0963-9969. (Elsevier B.V.)

Pigmented potato (Solanum tuberosum L.) varieties are a rich source of anthocyanins, in particular acylated derivs. From potato cultivars "Hermanns Blaue", "Highland Burgundy Red", "Shetland Black", and "Vitelotte" the major anthocyanins were isolated and characterized. Sliced potatoes were blanched to minimize enzymic reactions which cause degrdn. of anthocyanins. By means of solid phase extn., countercurrent chromatog. and preparative HPLC, it was possible to sep. coumaric acid derivs. (i.e. 3-p-coumaroylrutinoside-5-glucosides of petunidin, pelargonidin, peonidin and malvidin) from non-acylated anthocyanins as well as chlorogenic acids. Identity of the isolated compds. was detd. by combination of HPLC-DAD and LC-ESI-MS2 measurements. Petunidin derivs. were detected in all varieties except Highland Burgundy Red, where pelargonidin was found to be the only anthocyanidin. Malvidin was the predominant aglycon of the variety Vitelotte. Of the four selected cultivars, Shetland Black was the only one contg. minor amts. of peonidin derivs.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXntVOgtLc%253D&md5=82037ecbb3bd219f7d44f400fda29861

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Li, A. R. ; Xiao, R. S. ; He, S. J. ; An, X. Y. ; He, Y. ; Wang, C. T. ; Yin, S. ; Wang, B. ; Shi, X. W. ; He, J. R. Research Advances of Purple Sweet Potato Anthocyanins: Extraction, Identification, Stability, Bioactivity, Application, and Biotransformation. Molecules 2019, 24 , 3816, DOI: 10.3390/molecules24213816

[Crossref], [CAS], Google Scholar

246

Research advances of purple sweet potato anthocyanins: extraction, identification, stability, bioactivity, application, and biotransformation

Li, Aoran; Xiao, Ruoshi; He, Sijia; An, Xiaoyu; He, Yi; Wang, Chengtao; Yin, Sheng; Wang, Bin; Shi, Xuewei; He, Jingren

Molecules (2019), 24 (21), 3816CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

A review. Purple sweet potato anthocyanins are kinds of natural anthocyanin red pigments extd. from the root or stem of purple sweet potato. They are stable and have the functions of anti-oxidn., anti-mutation, anti-tumor, liver protection, hypoglycemia, and anti-inflammation, which confer them a good application prospect. Nevertheless, there is not a comprehensive review of purple sweet potato anthocyanins so far. The extn., structural characterization, stability, functional activity, application in the food, cosmetics, medicine, and other industries of anthocyanins from purple sweet potato, together with their biotransformation in vitro or by gut microorganism are reviewed in this paper, which provides a ref. for further development and utilization of anthocyanins.

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Zhao, C. L. ; Yu, Y. Q. ; Chen, Z. J. ; Wen, G. S. ; Wei, F. G. ; Zheng, Q. ; Wang, C. D. ; Xiao, X. L. Stability-Increasing Effects of Anthocyanin Glycosyl Acylation. Food Chem. 2017, 214 , 119– 128, DOI: 10.1016/j.foodchem.2016.07.073

[Crossref], [PubMed], [CAS], Google Scholar

247

Stability-increasing effects of anthocyanin glycosyl acylation

Zhao, Chang-Ling; Yu, Yu-Qi; Chen, Zhong-Jian; Wen, Guo-Song; Wei, Fu-Gang; Zheng, Quan; Wang, Chong-De; Xiao, Xing-Lei

Food Chemistry (2017), 214 (), 119-128CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

This review comprehensively summarizes the existing knowledge regarding the chem. implications of anthocyanin glycosyl acylation, the effects of acylation on the stability of acylated anthocyanins and the corresponding mechanisms. Anthocyanin glycosyl acylation commonly refers to the phenomenon in which the hydroxyl groups of anthocyanin glycosyls are esterified by aliph. or arom. acids, which is synthetically represented by the acylation sites as well as the types and nos. of acyl groups. Generally, glycosyl acylation increases the in vitro and in vivo chem. stability of acylated anthocyanins, and the mechanisms primarily involve physicochem., stereochem., photochem., biochem. or environmental aspects under specific conditions. Addnl., the acylation sites as well as the types and nos. of acyl groups influence the stability of acylated anthocyanins to different degrees. This review could provide insight into the optimization of the stability of anthocyanins as well as the application of suitable anthocyanins in food, pharmaceutical and cosmetic industries.

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Sharif, N. ; Khoshnoudi-Nia, S. ; Jafari, S. M. Nano/Microencapsulation of Anthocyanins; a Systematic Review and Meta-Analysis. Food Res. Int. 2020, 132 , 109077, DOI: 10.1016/j.foodres.2020.109077

[Crossref], [PubMed], [CAS], Google Scholar

248

Nano/microencapsulation of anthocyanins; a systematic review and meta-analysis

Sharif, Niloufar; Khoshnoudi-Nia, Sara; Jafari, Seid Mahdi

Food Research International (2020), 132 (), 109077CODEN: FORIEU; ISSN:0963-9969. (Elsevier B.V.)

A review. Anthocyanins, a kind of phenolic compds. are present in plant kingdom. They exhibit biol. activities such as anti-inflammatory and anti-cancer properties as well as imparting colors to various plants. The objective of this review is to provide a systematic evaluation of the evidence and a meta-anal. of published researches on the nano/microencapsulation of anthocyanins. A comprehensive literature search was conducted for articles published in 2016 to 2019 on PubMed, Web of Sciences and Scopus databases. Overall 45 eligible articles (51 cases; some authors studied 2 or more encapsulation methods) with appropriate data were included in the statistical anal. In the current work, based on the technique and equipment applied for the formulation of micro/nanoencapsulation systems, the anthocyanin-loaded nano/microcarriers were classified into five main classes: (a) spray dried particles (spray-drying); (b) freeze-dried particles (freeze-drying); (c) lipid-based particles (emulsification and liposomal encapsulation); (d) electrospun fibers and electrosprayed particles (electrohydrodynamic encapsulation); and (e) nano/micro-gels (gelation). Based on the results from the meta-anal., the studied technique for encapsulation of anthocyanins can be ordered as: spray-drying (33.33%), freeze-drying (27.08%), gelation (20.83%), lipid-based particles (14.58%) and electrohydrodynamic processes (4.17%). In addn., carbohydrates such as maltodextrin (19.56%) and gums (15.22%) have been the most frequently used biopolymers for encapsulation of anthocyanins in the selected studies.

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Yousuf, B. ; Gul, K. ; Wani, A. A. ; Singh, P. Health Benefits of Anthocyanins and Their Encapsulation for Potential Use in Food Systems: A Review. Crit. Rev. Food Sci. Nutr. 2016, 56 , 2223– 2230, DOI: 10.1080/10408398.2013.805316

[Crossref], [PubMed], [CAS], Google Scholar

249

Health Benefits of Anthocyanins and Their Encapsulation for Potential Use in Food Systems: A Review

Yousuf, Basharat; Gul, Khalid; Wani, Ali Abas; Singh, Preeti

Critical Reviews in Food Science and Nutrition (2016), 56 (13), 2223-2230CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)

A review. Anthocyanins are one of the six subgroups of large and widespread group of plant constituents known as flavonoids. These are responsible for the bright and attractive orange, red, purple, and blue colors of most fruits, vegetables, flowers and some cereal grains. More than 600 structurally distinct anthocyanins have been identified in nature. Earlier, anthocyanins were only known for their coloring properties but now interest in anthocyanin pigments has intensified because of their possible health benefits as dietary antioxidants, which help to prevent neuronal diseases, cardiovascular illnesses, cancer, diabetes, inflammation, and many such others diseases. Ability of anthocyanins to counter oxidants makes them atherosclerosis fighters. Therefore, anthocyanin-rich foods may help to boost overall health by offering an array of nutrients. However, the incorporation of anthocyanins into food and medical products is a challenging task due to their low stability toward environmental conditions during processing and storage. Encapsulation seems to be an efficient way to introduce such compds. into these products. Encapsulating agents act as a protector coat against ambient adverse conditions such as light, humidity, and oxygen. Encapsulated bioactive compds. are easier to handle and offer improved stability. The main objective of this review is to explore health benefits of anthocyanins and their extn., characterization, encapsulation, and delivery.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtleqsL%252FI&md5=c15fca80405ad1d3586ad65d4ac52e31

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Celli, G. B. ; Ghanem, A. ; Brooks, M. S. L. Optimized Encapsulation of Anthocyanin-Rich Extract from Haskap Berries (Lonicera Caerulea L.) in Calcium-Alginate Microparticles. J. Berry Res. 2016, 6 , 1– 11, DOI: 10.3233/JBR-150107

[Crossref], [CAS], Google Scholar

250

Optimized encapsulation of anthocyanin-rich extract from haskap berries (Lonicera caerulea L.) in calcium-alginate microparticles

Celli, Giovana Bonat; Ghanem, Amyl; Brooks, Marianne Su-Ling

Journal of Berry Research (2016), 6 (1), 1-11CODEN: JBROH4; ISSN:1878-5093. (IOS Press)

The chem. instability of extd. anthocyanins (ACNs) limits their application and broader use as food colorants and health-promoting functional ingredients. Encapsulation technol. can improve ACN stability and widen their potential applications. The objective of this study was to optimize the microencapsulation of ACNs from haskap berries (Lonicera caerulea L.) in calcium-alginate particles by the extrusion/gelation method. Response Surface Methodol. (RSM) by Box-Behnken (BB) design was used for the optimization, followed by the desirability function. Three input variables were evaluated: concns. of sodium alginate (x1, wt./wt. %) and calcium chloride (x2, w/v %), and gelation time (x3, min). The responses were encapsulation efficiency (y1, %) and particle size (y2, μm). There was a good fit for the model where encapsulation efficiency was used as a sep. response (R2=97.98%), however, the model for particle size did not give as good an agreement (R2=63.86%). The desirability function was used to optimize the two responses simultaneously and the optimum conditions were detd. as 9.0% (wt./wt.) alginate soln., 2.0% (w/v) CaCl2, and 10 min in the gelation soln. These results illustrate the application of RSM followed by a desirability function to optimize encapsulation parameters for a combined response, where several measures are considered.

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Guldiken, B. ; Gibis, M. ; Boyacioglu, D. ; Capanoglu, E. ; Weiss, J. Impact of Liposomal Encapsulation on Degradation of Anthocyanins of Black Carrot Extract by Adding Ascorbic Acid. Food Funct. 2017, 8 , 1085– 1093, DOI: 10.1039/C6FO01385F

[Crossref], [PubMed], [CAS], Google Scholar

251

Impact of liposomal encapsulation on degradation of anthocyanins of black carrot extract by adding ascorbic acid

Guldiken, Burcu; Gibis, Monika; Boyacioglu, Dilek; Capanoglu, Esra; Weiss, Jochen

Food & Function (2017), 8 (3), 1085-1093CODEN: FFOUAI; ISSN:2042-6496. (Royal Society of Chemistry)

Black carrot anthocyanins are known to be relatively stable because they contain acylated anthocyanins. The degrdn. of vitamin C (L-ascorbic acid) on anthocyanins is a known fact in beverage systems. In this study, the effects of various liposomal systems, including black carrot ext. (0.1%, 0.2%, 0.4% wt./wt.) and lecithin (1%, 2%, 4% wt./wt.), on the color and degrdn. of anthocyanin in different ascorbic acid (0.01%, 0.025%, 0.05%, 0.1% wt./wt.) concns. were examd. via UV/VIS spectroscopy and visual control of the color. The phys. characteristics of the liposomal systems resulted in particle diams. of 41-46 nm and zeta-potentials of (-23)-(-20) mV. The encapsulation efficiencies of the liposomal systems increased up to 50% with increasing lecithin concns. The encapsulation of black carrot ext. in liposomes enhanced the color and stability of the anthocyanins during storage. This study showed that the degrdn. of anthocyanins due to ascorbic acid can be reduced by liposomes in aq. solns.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjt1Gj&md5=8de214f6ea751ab380309293c64d2184

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Zhao, L.-y. ; Chen, J. ; Wang, Z.-q. ; Shen, R.-m. ; Cui, N. ; Sun, A.-d. Direct Acylation of Cyanidin-3-Glucoside with Lauric Acid in Blueberry and Its Stability Analysis. Int. J. Food Prop. 2016, 19 , 1– 12, DOI: 10.1080/10942912.2015.1016577

[Crossref], [CAS], Google Scholar

252

Direct Acylation of Cyanidin-3-Glucoside with Lauric Acid in Blueberry and Its Stability Analysis

Zhao, Li-yi; Chen, Jian; Wang, Zhi-qiang; Shen, Rui-meng; Cui, Nan; Sun, Ai-dong

International Journal of Food Properties (2016), 19 (1), 1-12CODEN: IJFPFO; ISSN:1094-2912. (Taylor & Francis, Inc.)

Cyanidin-3-glucoside is an anthocyanin that is abundant in blueberry. Lauric acid was used as the acyl donor in the acylation of cyanidin-3-glucoside. Preparative high performance liq. chromatog. was used to sep. and purify the acylated cyanidin-3-glucoside, the acylated rate was 30.78%. Fourier transform IR spectroscopy and liq. chromatog. mass spectrometry were used to confirm the basic structure of cyanidin-3-glucoside. Lauric acid was combined with cyanidin-3-glucoside. Lauric acid reacted with the glucoside's primary hydroxyl group and removed a mol. of water, thereby resulting in the obtained structure. The compns. of the unacylated cyanidin-3-glucoside and acylated cyanidin-3-glucoside were compared under different temps. and under illumination. The effects of different concns. of additive compds. on the stability of acylated cyanidin-3-glucoside were compared. Stability of acylated cyanidin-3-glucoside was obviously higher than that of the unacylated cyanidin-3-glucoside because of the higher stability of the ester group than the hydroxyl group. The primary hydroxyl esterification of glucoside improved cyanidin-3-glucoside.

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Cruz, L. ; Fernandes, V. C. ; Araújo, P. ; Mateus, N. ; de Freitas, V. Synthesis, Characterisation and Antioxidant Features of Procyanidin B4 and Malvidin-3-Glucoside Stearic Acid Derivatives. Food Chem. 2015, 174 , 480– 486, DOI: 10.1016/j.foodchem.2014.11.062

[Crossref], [PubMed], [CAS], Google Scholar

253

Synthesis, characterisation and antioxidant features of procyanidin B4 and malvidin-3-glucoside stearic acid derivatives

Cruz, Luis; Fernandes, Virginia C.; Araujo, Paula; Mateus, Nuno; de Freitas, Victor

Food Chemistry (2015), 174 (), 480-486CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The acylation of procyanidin B4 with a satd. fatty acid chloride contg. 18 carbon atoms was studied in order to obtain procyanidin B4 3-O-di-stearic acid conjugate. This compd. was structurally characterized by mass spectrometry and 1D and 2D NMR techniques. Derivatization of malvidin-3-glucoside using stearoyl chloride in acetonitrile was also performed yielding mono-, di- and tri-stearic ester derivs. The novel derivs. obtained revealed significant antioxidant activity, although lower than the resp. precursors. However, the chem. modification of anthocyanins and procyanidins (water-sol. pigments) to more lipophilic compds. has the advantage of increased bioavailability in biol. matrixes, and to potentiate their application in food matrixes and cosmetic products.

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Grajeda-Iglesias, C. ; Salas, E. ; Barouh, N. ; Baréa, B. ; Figueroa-Espinoza, M. C. Lipophilization and Ms Characterization of the Main Anthocyanins Purified from Hibiscus Flowers. Food Chem. 2017, 230 , 189– 194, DOI: 10.1016/j.foodchem.2017.02.140

[Crossref], [PubMed], [CAS], Google Scholar

254

Lipophilization and MS characterization of the main anthocyanins purified from hibiscus flowers

Grajeda-Iglesias, Claudia; Salas, Erika; Barouh, Nathalie; Barea, Bruno; Figueroa-Espinoza, Maria Cruz

Food Chemistry (2017), 230 (), 189-194CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Hibiscus sabdariffa flowers represent an interesting source of anthocyanins, one of the most important plant pigments, which are responsible of the intense red color of the calyces, and have potential as natural colorants for food applications. Nevertheless, anthocyanins are highly hydrosol. and unstable compds. On this basis, the aim of this work was to increase the lipophilicity of the hibiscus anthocyanins by lipophilization, in order to obtain amphiphilic colorants, which could be easily incorporated in lipid-rich food matrixes. Octanoyl derivs. of delphinidin-3-O-sambubioside and cyanidin-3-O-sambubioside were chem. obtained for the first time, and characterized by means of HPLC-ESI-MS data.

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Cruz, L. ; Guimaraes, M. ; Araujo, P. ; Evora, A. ; de Freitas, V. ; Mateus, N. Malvidin 3-Glucoside-Fatty Acid Conjugates: From Hydrophilic toward Novel Lipophilic Derivatives. J. Agric. Food Chem. 2017, 65 , 6513– 6518, DOI: 10.1021/acs.jafc.6b05461

[ACS Full Text ], [CAS], Google Scholar

255

Malvidin 3-Glucoside-Fatty Acid Conjugates: From Hydrophilic toward Novel Lipophilic Derivatives

Cruz, Luis; Guimaraes, Marta; Araujo, Paula; Evora, Ana; de Freitas, Victor; Mateus, Nuno

Journal of Agricultural and Food Chemistry (2017), 65 (31), 6513-6518CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

This work reports the lipophilization of malvidin 3-glucoside with different satd. fatty acid chain lengths using an enzymic synthesis approach. The lipophilic anthocyanins were obtained with satisfactory yields (22-40%) after column chromatog. purifications and they revealed the same appealing chromatic features of the parent anthocyanin. All the compds. were characterized by mass spectrometry confirming the regioselective acylation on the glucose moiety. The octanol-water partition coeffs. and the hydrophobicity index of the different derivs. were detd. confirming a lipophilicity increase concomitant with the fatty acid chain length. The antioxidant profile was also evaluated by two in vitro methods (β-Carotene-lineolate method and oxygen consumption assay). Overall, a max. of antioxidant activity was achieved when malvidin 3-glucoside was conjugated with caprylic acid (C8). Altogether, the results obtained provides a good perspective for the technol. application of these functionalized anthocyanins in cosmetic and food industries.

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De Castro, V. C. ; Alves da Silva, P. H. ; de Oliveira, E. B. ; Desobry, S. ; Humeau, C. Extraction, Identification and Enzymatic Synthesis of Acylated Derivatives of Anthocyanins from Jaboticaba (Myrciaria Cauliflora) Fruits. Int. J. Food Sci. Technol. 2014, 49 , 196– 204, DOI: 10.1111/ijfs.12298

[Crossref], [CAS], Google Scholar

256

Extraction, identification and enzymatic synthesis of acylated derivatives of anthocyanins from jaboticaba (Myrciaria cauliflora) fruits

de Castro, Vanessa Cristina; Alves da Silva, Paulo Henrique; Basilio de Oliveira, Eduardo; Desobry, Stephane; Humeau, Catherine

International Journal of Food Science and Technology (2014), 49 (1), 196-204CODEN: IJFTEZ; ISSN:0950-5423. (Wiley-Blackwell)

Polyphenols were extd. from the skin of jabuticaba fruits (Myrciaria cauliflora). Their total concn. and in vitro antioxidant activity were analyzed by the DPPH and ABTS methods. The corresponding results (dry basis) were 1290 mg gallic acid equiv. (GAE)·(100 g)-1, 98% of DPPH radical inhibition and 120 μmTEAC·-1 (ABTS method). All these values are at least as higher as av. values reported in the literature for other fruits. A more specific anal. of the fractions of phenolic compds. was also performed by HPLC-MS. Ellagic acid, quercetin, rutin, delphinidin-3-glucoside and cyanidin-3-glucoside were the main compds. detected; the latter two were the most abundant. The crude ext. was subjected to enzymic acylation assays in order to synthesize new esters with new potential techno-functionalities. Palmitic acid was used as acyl donor and lipase B of Candida antactica (CALB) as biocatalyst. HPLC-MS evidenced the formation of palmitic monoesters in connection with the delphinidin-3-glucoside and cyanidin-3-glucoside fractions.

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Yang, W. ; Kortesniemi, M. ; Yang, B. ; Zheng, J. Enzymatic Acylation of Anthocyanins Isolated from Alpine Bearberry (Arctostaphylos Alpina) and Lipophilic Properties, Thermostability, and Antioxidant Capacity of the Derivatives. J. Agric. Food Chem. 2018, 66 , 2909– 2916, DOI: 10.1021/acs.jafc.7b05924

[ACS Full Text ], [CAS], Google Scholar

257

Enzymatic Acylation of Anthocyanins Isolated from Alpine Bearberry (Arctostaphylos alpina) and Lipophilic Properties, Thermostability, and Antioxidant Capacity of the Derivatives

Yang, Wei; Kortesniemi, Maaria; Yang, Baoru; Zheng, Jie

Journal of Agricultural and Food Chemistry (2018), 66 (11), 2909-2916CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Cyanidin-3-O-galactoside (cy-gal) isolated from alpine bearberry (Arctostaphylos alpine L.) was enzymically acylated with satd. fatty acids of different chain lengths with Candida antarctica lipase immobilized on acrylic resin (Novozyme 435). The acylation reaction was optimized by considering the reaction medium, acyl donor, substrate molar ratio, reaction temp., and reaction time. The highest conversion yield of 73% was obtained by reacting cy-gal with lauric acid (molar ratio of 1:10) in tert-butanol at 60 °C for 72 h. A novel compd. was synthesized, which was identified as cyanidin-3-O-(6''-dodecanoyl)galactoside by mass spectrometry and NMR. Introducing lauric acid into cy-gal significantly improved both the lipophilicity and thermostability and substantially preserved the UV-visible absorbance and antioxidant properties. The research provides important insight in expanding the application of natural anthocyanins in the cosmetic and food industries.

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258

Cruz, L. ; Benohoud, M. ; Rayner, C. M. ; Mateus, N. ; de Freitas, V. ; Blackburn, R. S. Selective Enzymatic Lipophilization of Anthocyanin Glucosides from Blackcurrant (Ribes Nigrum L.) Skin Extract and Characterization of Esterified Anthocyanins. Food Chem. 2018, 266 , 415– 419, DOI: 10.1016/j.foodchem.2018.06.024

[Crossref], [PubMed], [CAS], Google Scholar

258

Selective enzymatic lipophilization of anthocyanin glucosides from blackcurrant (Ribes nigrum L.) skin extract and characterization of esterified anthocyanins

Cruz, Luis; Benohoud, Meryem; Rayner, Christopher M.; Mateus, Nuno; de Freitas, Victor; Blackburn, Richard S.

Food Chemistry (2018), 266 (), 415-419CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Anthocyanins (ANC) are hydrophilic and water-sol. polyphenolic plant pigments. The current barriers to successful application of ANC in the food, cosmetic and pharmaceutical industries are predominantly related to performance, stability, formulation properties, and color. Enzymic acylation of ANC could increase their stability without compromising bioactivity and chromatic features. Lipophilization of ANC-rich blackcurrant skin ext. with Candida antarctica lipase B and octanoic acid was selective to cyanidin and delphinidin glucosides, but not the corresponding rutinosides. The reaction was chemo- and regioselective for acylation at the primary alc. of the glucose moieties, greatly facilitating sepn. of the different glycoside derivs.

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259

Cruz, L. ; Fernandes, I. ; Guimaraes, M. ; de Freitas, V. ; Mateus, N. Enzymatic Synthesis, Structural Characterization and Antioxidant Capacity Assessment of a New Lipophilic Malvidin-3-Glucoside-Oleic Acid Conjugate. Food Funct. 2016, 7 , 2754– 2762, DOI: 10.1039/C6FO00466K

[Crossref], [PubMed], [CAS], Google Scholar

259

Enzymatic synthesis, structural characterization and antioxidant capacity assessment of a new lipophilic malvidin-3-glucoside-oleic acid conjugate

Cruz, Luis; Fernandes, Iva; Guimaraes, Marta; de Freitas, Victor; Mateus, Nuno

Food & Function (2016), 7 (6), 2754-2762CODEN: FFOUAI; ISSN:2042-6496. (Royal Society of Chemistry)

The chem. modification of anthocyanins (water-sol. pigments) into more lipophilic compds. is very important to expand their application in the food, medical and cosmetic industries. In this work, the synthesis of a pure malvidin-3-glucoside-oleic acid ester deriv. was achieved by enzymic catalysis. This approach allowed us to synthesize a novel compd., malvidin-3-O-(6''-oleoyl)glucoside (Mv3glc-OA), which was structurally characterized by mass spectrometry and for the first time by NMR spectroscopy. The enzymic reaction revealed to be regioselective giving only one ester product. Antioxidant features of the malvidin-3-glucoside lipophilic deriv. by means of DPPH, FRAP and lipid peroxidn. assays were assessed, which confirmed that the structural modification of the genuine malvidin-3-glucoside into a more lipophilic compd. did not compromise its antioxidant potential and protected more effectively a lipidic substrate from oxidn., which is an important insight for future technol. applications.

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260

Cruz, L. ; Guimarães, M. ; Araújo, P. ; Évora, A. ; de Freitas, V. ; Mateus, N. Malvidin 3-Glucoside–Fatty Acid Conjugates: From Hydrophilic toward Novel Lipophilic Derivatives. J. Agric. Food Chem. 2017, 65 , 6513– 6518, DOI: 10.1021/acs.jafc.6b05461

[ACS Full Text ], [CAS], Google Scholar

260

Malvidin 3-Glucoside-Fatty Acid Conjugates: From Hydrophilic toward Novel Lipophilic Derivatives

Cruz, Luis; Guimaraes, Marta; Araujo, Paula; Evora, Ana; de Freitas, Victor; Mateus, Nuno

Journal of Agricultural and Food Chemistry (2017), 65 (31), 6513-6518CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

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261

Guimarães, M. ; Mateus, N. ; de Freitas, V. ; Cruz, L. Improvement of the Color Stability of Cyanidin-3-Glucoside by Fatty Acid Enzymatic Acylation. J. Agric. Food Chem. 2018, 66 , 10003– 10010, DOI: 10.1021/acs.jafc.8b03536

[ACS Full Text ], [CAS], Google Scholar

261

Improvement of the Color Stability of Cyanidin-3-glucoside by Fatty Acid Enzymatic Acylation

Guimaraes, Marta; Mateus, Nuno; de Freitas, Victor; Cruz, Luis

Journal of Agricultural and Food Chemistry (2018), 66 (38), 10003-10010CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Anthocyanins are water-sol. pigments with limited application in lipophilic matrixes such as lipid-based foods and cosmetic formulations. In this work, the liposoly. improvement of cyanidin-3-glucoside (cy3glc) was performed by enzymic esterification with satd. fatty acids with variable chain lengths, and their thermostabilities were evaluated at different pH values in a lipophilic medium (an aq. sodium dodecyl sulfate soln.) by means of UV-vis spectroscopy. Overall, lipophilic cy3glc derivs. showed improved color stability and lowered sensitivity to thermal degrdn. than nonmodified cy3glc in an SDS micellar soln. between pH 3 and 7.

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Mendoza, J. ; Pina, F. ; Basílio, N. ; Guimarães, M. ; de Freitas, V. ; Cruz, L. Extending the Stability of Red and Blue Colors of Malvidin-3-Glucoside-Lipophilic Derivatives in the Presence of Sds Micelles. Dyes Pigm. 2018, 151 , 321– 326, DOI: 10.1016/j.dyepig.2018.01.007

[Crossref], [CAS], Google Scholar

262

Extending the stability of red and blue colors of malvidin-3-glucoside-lipophilic derivatives in the presence of SDS micelles

Mendoza, Johan; Pina, Fernando; Basilio, Nuno; Guimaraes, Marta; de Freitas, Victor; Cruz, Luis

Dyes and Pigments (2018), 151 (), 321-326CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Anthocyanins lipophilization recently emerged as an efficient tool to deliver oil-sol. dyes aiming to expand their applications in lipophilic matrixes such as cosmetics formulations. Sodium dodecyl sulfate (SDS) micelles were used to solubilize malvidin-3-glucoside derivs. bearing an ester chain derived from dodecanoic and hexanoic fatty acids. Detailed investigations on the kinetic and thermodn. behavior of the pigments towards pH variations was carried out by means of UV-Vis spectroscopy. It was found that the pH domain of the red flavylium cation is extended in ca 0.3-0.4 pH units. The mole fraction of the quinoidal base at neutral conditions increased by 40% when compared with malvidin-3-glucoside in the same micellar media, which provides a great blue color stabilization. The results presented herein report for the first time the blue color stabilization of these lipophilic anthocyanin bioactives, opening new application fields as novel colorants for lipid-based foods and cosmetics.

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Cruz, L. ; Basílio, N. ; de Freitas, V. Color Stabilization of Cyanidin-3-Glucoside-Based Dyes by Encapsulation with Biocompatible Pegylated Phospholipid Micelles. Dyes Pigm. 2020, 181 , 108592, DOI: 10.1016/j.dyepig.2020.108592

[Crossref], [CAS], Google Scholar

263

Color stabilization of cyanidin-3-glucoside-based dyes by encapsulation with biocompatible PEGylated phospholipid micelles

Cruz, Luis; Basilio, Nuno; de Freitas, Victor

Dyes and Pigments (2020), 181 (), 108592CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Anthocyanins color stabilization is a const. concern of the scientific community which has been searching different approaches since encapsulation technol. to development of new host-guest systems. The interaction between a biocompatible self-assembled system (PEGylated phospholipid micelles) and two anthocyanin dyes was studied by UV-visible, stopped-flow, NMR and DLS. Overall, the results obtained clearly showed a superior stabilization and intensification effect on the colored species of anthocyanin dyes in the presence of PEGylated phospholipid micelles. The red flavylium cation of cyanidin-3-glucoside was preferentially encapsulated by the neg. charged micelles rather than the colorless hemiketal species resulting in an increase of absorbance of the soln. color in 36% at pH 3.5. The thermodn. consts. were also modulated in the presence of the micelles, namely the hydration const. (pKh) and the apparent acidic equil. const. (pK'a) increased in 0.5-0.6 pH units. In the case of the anthocyanin lipophilic pigment, it was obsd. an increase in the mole fraction of blue quinoidal base concomitantly with the decrease of the hemiketal species from pH >6 (circa 40%) displaying stable bluish colored solns. The tuning and color stabilization of anthocyanin-based dyes using this biocompatible system envisage novel applications such as colorimetric sensors for food packaging.

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264

Lima, J. C. ; Vautier-Giongo, C. ; Lopes, A. ; Melo, E. ; Quina, F. H. ; Macanita, A. L. Color Stabilization of Anthocyanins: Effect of Sds Micelles on the Acid-Base and Hydration Kinetics of Malvidin 3-Glucoside (Oenin). J. Phys. Chem. A 2002, 106 , 5851– 5859, DOI: 10.1021/jp014081c

[ACS Full Text ], [CAS], Google Scholar

264

Color Stabilization of Anthocyanins: Effect of SDS Micelles on the Acid-Base and Hydration Kinetics of Malvidin 3-Glucoside (Oenin)

Lima, Joao C.; Vautier-Giongo, Carolina; Lopes, Antonio; Melo, Eurico; Quina, Frank H.; Macanita, Antonio L.

Journal of Physical Chemistry A (2002), 106 (24), 5851-5859CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

The origin of the substantial stabilization of the color of the natural anthocyanin malvidin-3-glucosyl chloride (Oenin) in aq. micellar SDS solns. was elucidated by employing laser flash photolysis and pH-jump techniques to det. all four rate consts. involved in the acid-base and hydration reactions of Oenin. These rate data show that the pronounced stabilizing effect of SDS micelles on the color of aq. solns. of Oenin, as measured by the shift in the bleaching const. (pK1/2) from moderately acid to near-neutral pH, cannot be attributed just to the difference in local pH between the aq. and micellar phases. Thus, the major contribution to the SDS-induced shift in the acid-base equil. const. arises from the large decrease in the deprotonation rate const. in SDS micelles (kd = 2 × 105 s-1) with respect to water (kd = 5.0 × 106 s-1). Although the hydration rate const. also decreases in SDS micelles (kh = 4.6 × 10-3 s-1 vs. kh = 8.5 × 10-2 s-1 in water), the major contribution to the obsd. shift in the hydration equil. const. comes from the back reaction (k-h = 7.1 × 103 l mol-1 s-1 in SDS vs. k-h = 34 L mol-1 s-1 in water). The present results conclusively demonstrate that color stabilization by anionic SDS micelles involves significant preferential stabilization of the cationic form of Oenin with respect to the neutral base, hemiacetal and E-chalcone forms, resulting in profound changes in the energetics of deprotonation and hydration, the two key equil. that affect color.

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Bandara, H. M. D. ; Burdette, S. C. Photoisomerization in Different Classes of Azobenzene. Chem. Soc. Rev. 2012, 41 , 1809– 1825, DOI: 10.1039/C1CS15179G

[Crossref], [PubMed], [CAS], Google Scholar

265

Photoisomerization in different classes of azobenzene

Bandara, H. M. Dhammika; Burdette, Shawn C.

Chemical Society Reviews (2012), 41 (5), 1809-1825CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Azobenzene undergoes trans cis isomerization when irradiated with light tuned to an appropriate wavelength. The reverse cis trans isomerization can be driven by light or occurs thermally in the dark. Azobenzene's photochromatic properties make it an ideal component of numerous mol. devices and functional materials. Despite the abundance of application-driven research, azobenzene photochem. and the isomerization mechanism remain topics of study. Addnl. substituents on the azobenzene ring system change the spectroscopic properties and isomerization mechanism. This crit. review details the studies completed to date on the 3 main classes of azobenzene derivs. Understanding the differences in photochem., which originate from substitution, is imperative in exploiting azobenzene in the desired applications.

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Irie, M. ; Fukaminato, T. ; Matsuda, K. ; Kobatake, S. Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators. Chem. Rev. 2014, 114 , 12174– 12277, DOI: 10.1021/cr500249p

[ACS Full Text ], [CAS], Google Scholar

266

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

Irie, Masahiro; Fukaminato, Tuyoshi; Matsuda, Kenji; Kobatake, Seiya

Chemical Reviews (Washington, DC, United States) (2014), 114 (24), 12174-12277CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review of diarylethene mols. and their photochromic properties is discussed. Numerous applications, such as optical memory devices, optical switches, and actuators, are detailed. The effects of chem. modifications via different functional group derivs. on the photochromic properties are all also discussed.

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267

Klajn, R. Spiropyran-Based Dynamic Materials. Chem. Soc. Rev. 2014, 43 , 148– 184, DOI: 10.1039/C3CS60181A

[Crossref], [PubMed], [CAS], Google Scholar

267

Spiropyran-based dynamic materials

Klajn, Rafal

Chemical Society Reviews (2014), 43 (1), 148-184CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. In the past few years, spiropyran has emerged as the mol. of choice for the construction of novel dynamic materials. This unique mol. switch undergoes structural isomerization in response to a variety of orthogonal stimuli, e.g. light, temp., metal ions, redox potential, and mech. stress. Incorporation of this switch onto macromol. supports or inorg. scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromols., inorg. nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.

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Kortekaas, L. ; Browne, W. R. The Evolution of Spiropyran: Fundamentals and Progress of an Extraordinarily Versatile Photochrome. Chem. Soc. Rev. 2019, 48 , 3406– 3424, DOI: 10.1039/C9CS00203K

[Crossref], [PubMed], [CAS], Google Scholar

268

The evolution of spiropyran: fundamentals and progress of an extraordinarily versatile photochrome

Kortekaas, Luuk; Browne, Wesley R.

Chemical Society Reviews (2019), 48 (12), 3406-3424CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

Spiropyrans have played a pivotal role in the emergence of the field of chromism following their discovery in the early 20th century, with almost ubiquitous use in materials applications esp. since their photochromism was discovered in 1952. Their versatility continues to lend them to application in increasingly diverse fields not least due to recent discoveries of properties that have expanded their utility extensively. This review provides an overview of their rich history and highlights the contemporary relevance of the spiropyrans.

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269

Silva, V. O. ; Freitas, A. A. ; Maçanita, A. L. ; Quina, F. H. Chemistry and Photochemistry of Natural Plant Pigments: The Anthocyanins. J. Phys. Org. Chem. 2016, 29 , 594– 599, DOI: 10.1002/poc.3534

[Crossref], [CAS], Google Scholar

269

Chemistry and photochemistry of natural plant pigments: the anthocyanins

Silva, Volnir O.; Freitas, Adilson A.; Macanita, Antonio L.; Quina, Frank H.

Journal of Physical Organic Chemistry (2016), 29 (11), 594-599CODEN: JPOCEE; ISSN:0894-3230. (John Wiley & Sons Ltd.)

A review. Anthocyanins are naturally occurring plant pigments responsible for the red, blue, and purple colors of the majority of fruits, flowers, and leaves. The pH-dependent ground-state chem. of anthocyanins is extremely rich. Above about pH 2.5, the colored flavylium cation form typically hydrates to form the colorless hemiacetal, followed by ring-opening tautomerization to the (E)-chalcone, which can isomerize to the (Z)-chalcone. The color of anthocyanins can also be modulated and/or stabilized by complexation with metal ions or with colorless org. mols. (copigments) such as hydroxylated benzoic or cinnamic acids. An understanding of the chem. that contributes to the loss of color is essential for the development of novel and more effective strategies for the stabilization of the color above pH 3, which would permit the use of anthocyanins as natural pigments in a much wider range of foods or consumer products. In the excited state, uncomplexed anthocyanins undergo ultrafast adiabatic deprotonation (5-20 ps) in aq. soln. to give the corresponding short-lived (about 200 ps) excited quinonoidal base. Intermol. and intramol. complexes of anthocyanins with org. copigments undergo deactivation that is even faster than deprotonation. The colorless hydration products are photoactive in the UV; thus, the chalcones undergo E-Z photoisomerization, while the hemiacetal form of anthocyanins exhibits photochem. typical of a chromene. These photoprocesses all potentially contribute to the photostability of anthocyanins in fruit and flowers and are fully consistent with the biol. role of anthocyanins in protecting leaves from excess solar radiation. Copyright © 2016 John Wiley & Sons, Ltd.

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Xiong, Y. ; Zhang, P. Z. ; Warner, R. D. ; Fang, Z. X. 3-Deoxyanthocyanidin Colorant: Nature, Health, Synthesis, and Food Applications. Compr. Rev. Food Sci. Food Saf. 2019, 18 , 1533– 1549, DOI: 10.1111/1541-4337.12476

[Crossref], [PubMed], [CAS], Google Scholar

270

3-Deoxyanthocyanidin Colorant: Nature, Health, Synthesis, and Food Applications

Xiong, Yun; Zhang, Pangzhen; Warner, Robyn Dorothy; Fang, Zhongxiang

Comprehensive Reviews in Food Science and Food Safety (2019), 18 (5), 1533-1549CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)

A review. 3-Deoxyanthocyanidins are a rare type of anthocyanins that are present in mosses, ferns, and some flowering plants. They are water-sol. pigments and impart orange-red and blue-violet color to plants and play a role as phytoalexins against microbial infection and environmental stress. In contrast to anthocyanins, the lack of a hydroxyl group at the C-3 position confers unique chem. and biochem. properties. They are potent natural antioxidants with a no. of potential health benefits including cancer prevention. 3-Deoxyanthocyanidin pigments have attracted much attention in the food industry as natural food colorants, mainly due to their higher stability during processing and handling conditions compared with anthocyanins. They are also photochromic compds. capable of causing a change in "perceived" color, when exposed to UV light, which can be used to design novel foods and beverages. Due to their interesting properties and potential industrial applications, great efforts have been made to synthesize these compds. For biosynthesis, researchers have discovered the 3-deoxyanthocyanidin biosynthetic pathway and their biosynthetic genes. For chem. synthesis, advances have been made to synthesize the compds. in a simpler and more efficient way as well as looking for its novel deriv. with enhanced coloration properties. This review summarizes the developments in the research on 3-deoxyanthocyanidin as a colorant, from natural sources to chem. syntheses and from health benefits to applications and future prospects, providing comprehensive insights into this group of interesting compds.

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Pina, F. ; Melo, M. J. ; Ballardini, R. ; Flamigni, L. ; Maestri, M. Flash Photolysis of 4',7-Dihydroxyflavylium Perchlorate. New J. Chem. 1997, 21 , 969– 976

[CAS], Google Scholar

271

Flash photolysis of 4',7-dihydroxyflavylium perchlorate

Pina, Fernando; Melo, Maria Joao; Ballardini, Roberto; Flamigni, Lucia; Maestri, Mauro

New Journal of Chemistry (1997), 21 (9), 969-976CODEN: NJCHE5; ISSN:1144-0546. (Gauthier-Villars)

In this work flash photolysis is applied for the first time to study kinetic processes involving synthetic flavylium salts and anthocyanins. This method proves to be a unique tool for the study of 4',7-dihydroxyflavylium salt, having shown that in this compd. the cis-trans isomerization is not the detg. step in the process that converts the flavylium cation into trans-chalcone. This role is attributed to the hydration reaction, in contrast with previous results obtained for 4'-substituted synthetic flavylium salts and anthocyanins.

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272

Castet, F. ; Champagne, B. ; Pina, F. ; Rodriguez, V. A Multistate Ph-Triggered Nonlinear Optical Switch. ChemPhysChem 2014, 15 , 2221– 2224, DOI: 10.1002/cphc.201402190

[Crossref], [PubMed], [CAS], Google Scholar

272

A Multistate pH-Triggered Nonlinear Optical Switch

Castet, Frederic; Champagne, Benoit; Pina, Fernando; Rodriguez, Vincent

ChemPhysChem (2014), 15 (11), 2221-2224CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)

By using hyper-Rayleigh scattering expts. and quantum-chem. calcns., nonlinear optics can be used to probe unequivocally, within a nondestructive process, the multiple electronic states that are activated upon pH- and light-triggered transformations of 4'-hydroxyflavylium ion. These results open new perspectives in the design of mol.-scale high-d. optical memory.

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273

Gago, S. ; Basílio, N. ; Moro, A. J. ; Pina, F. Flavylium Based Dual Photochromism: Addressing Cis–Trans Isomerization and Ring Opening-Closure by Different Light Inputs. Chem. Commun. 2015, 51 , 7349– 7351, DOI: 10.1039/C5CC01677K

[Crossref], [PubMed], [CAS], Google Scholar

273

Flavylium based dual photochromism: addressing cis-trans isomerization and ring opening-closure by different light inputs

Gago, Sandra; Basilio, Nuno; Moro, Artur J.; Pina, Fernando

Chemical Communications (Cambridge, United Kingdom) (2015), 51 (34), 7349-7351CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

The multistate system of 4',7-dihydroxy-3-methoxyflavylium is constituted by a multiequil. involving trans-chalcone, cis-chalcone, hemiketal, flavylium cation and quinoidal base. This system possesses two independently addressable inter-connected photochromic systems based on the cis-trans isomerization and ring opening-closure of the hemiketal.

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274

Horiuchi, H. ; Shirase, H. ; Okutsu, T. ; Matsushima, R. ; Hiratsuka, H. Photochromism of 2-Hydroxy-4″-Methoxychalcone: A Novel Photon-Mode Erasable Optical Memory System with Nondestructive Readout Ability. Chem. Lett. 2000, 29 , 96– 97, DOI: 10.1246/cl.2000.96

275

Wünscher, H. ; Haucke, G. ; Czerney, P. ; Kurzer, U. Photochromic Properties of Hydrolyzed Benzopyrylium Salts─the Influence of Substituents. J. Photochem. Photobiol., A 2002, 151 , 75– 82, DOI: 10.1016/S1010-6030(02)00017-5

[Crossref], [CAS], Google Scholar

275

Photochromic properties of hydrolyzed benzopyrylium salts - the influence of substituents

Wunscher, Heike; Haucke, Gunter; Czerney, Peter; Kurzer, Ute

Journal of Photochemistry and Photobiology, A: Chemistry (2002), 151 (1-3), 75-82CODEN: JPPCEJ; ISSN:1010-6030. (Elsevier Science B.V.)

A series of systematically modified benzopyrylium salts was hydrolyzed to study the influence of donor substituents in 4-, 7- and 4'-position of the benzopyrylium cation on photochromic systems. A photochromic behavior was obsd. at the 7- and 4'-substituted flavylium salts, whereas the insertion of 4-Ph group prevents the formation of a photochromic system. The photochem. quantum yield varies strongly depending on the substituents and the medium conditions. Good reaction quantum yields were found in highly viscous borax-glycerol mixts. The exclusively OH- and OMe-substituted chalcones exhibit photochem. quantum yields up to 0.6, whereas the NR2-substituted ones show quantum yields usually below 0.1. As a rule the latter ones fluoresce more intensively, indicating that the S1 state of the trans-chalcone is the common precursor for the photochem. formation of flavylium cation. The differences in the reaction quantum yields can be referred to the different tendency of the formation of a highly polar state on the S1 hypersurface, presumably a twisted intramol. charge transfer state (TICT).

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276

Costa, D. ; Galvão, A. M. ; Di Paolo, R. E. ; Freitas, A. A. ; Lima, J. C. ; Quina, F. H. ; Maçanita, A. L. Photochemistry of the Hemiketal Form of Anthocyanins and Its Potential Role in Plant Protection from Uv-B Radiation. Tetrahedron 2015, 71 , 3157– 3162, DOI: 10.1016/j.tet.2014.06.092

[Crossref], [CAS], Google Scholar

276

Photochemistry of the hemiketal form of anthocyanins and its potential role in plant protection from UV-B radiation

Costa, Damien; Galvao, Adelino M.; Di Paolo, Roberto E.; Freitas, Adilson A.; Lima, Joao C.; Quina, Frank H.; Macanita, Antonio L.

Tetrahedron (2015), 71 (20), 3157-3162CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

There is presently strong evidence that anthocyanins protect plant tissues from excessive solar radiation. In support of this, we have shown that the red flavylium form of anthocyanins (AH+) dissipates more than 99% of the absorbed radiation energy into heat through a series of ultra-fast excited-state processes, among which excited-state proton transfer to water plays the major role. In this work, it is shown for the first time that the less exuberant (colorless) hemiketal form of three common anthocyanins (pelargonin, cyanin, and malvin) is equally efficient at dissipating the absorbed (UV-B) radiation into heat by fast photo-tautomerization, which yields the cis-chalcone form in its ground state in a few picoseconds.

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277

Weller, A. Allgemeine Basenkatalyse Bei Der Elektrolytischen Dissoziation Angeregter Naphthole. Zeitschrift für Elektrochemie, Berichte der Bunsengesellschaft für physikalische Chemie 1954, 58 , 849– 853

278

Basilio, N. ; Laia, C. A. T. ; Pina, F. Excited-State Proton Transfer in Confined Medium. 4-Methy1–7-Hydroxyflavylium and Beta-Naphthol Incorporated in Cucurbit 7 Uril. J. Phys. Chem. B 2015, 119 , 2749– 2757, DOI: 10.1021/jp511351w

[ACS Full Text ], [CAS], Google Scholar

278

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

Basilio, Nuno; Laia, Cesar A. T.; Pina, Fernando

Journal of Physical Chemistry B (2015), 119 (6), 2749-2757CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

Excited-state proton transfer (ESPT) was studied by fluorescent emission using a math. model recast from the Weller theory. The titrn. curves can be fitted with three parameters: pKa (acidity const. of the ground sate), pK*ap (apparent acidity const. of the excited state), and ηA*, the efficiency of excited base formation from the excited acid. β-Naphthol and 4-methyl-7-hydroxyflavylium were studied in aq. soln. and upon incorporation in cucurbit[7]uril. For all the compds. studied the interaction with the host leads to 1:1 adducts and the ground-state pKa increases upon incorporation. Whereas the ESPT of 4-methyl-7-hydroxyflavylium practically does not change in the presence of the host, in the case of β-naphthol it is prevented and the fluorescence emission titrn. curves are coincident with those taken by absorption. The position of the guest inside the host was investigated by NMR expts. and seems to det. the efficiency of the ESPT. The ESPT decreases for the guest, exhibiting a great protection of the phenol to the bulk water interaction.

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In reference

Basílio, N. ; Laia, C. A. T. Excited-State Proton Transfer in Confined Medium. 4-Methy1-7-hydroxyflavylium and beta-Naphthol Incorporated in Cucurbit[7]uril. J. Phys. Chem. B 2015, 119 , 2749– 2757, where is written k_ap ^* shoul be k_a ^* (rate constant that gives A^* from AH^+*) in Scheme 6.1 DOI: 10.1021/jp511351w

[ACS Full Text ], [CAS], Google Scholar

279

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

Basilio, Nuno; Laia, Cesar A. T.; Pina, Fernando

Journal of Physical Chemistry B (2015), 119 (6), 2749-2757CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFaqur3I&md5=da0a92100f4c5988833ce30e8a297d44

280

Moreira, P. F. ; Giestas, L. ; Yihwa, C. ; Vautier-Giongo, C. ; Quina, F. H. ; Macanita, A. L. ; Lima, J. C. Ground- and Excited-State Proton Transfer in Anthocyanins: From Weak Acids to Superphotoacids. J. Phys. Chem. A 2003, 107 , 4203– 4210, DOI: 10.1021/jp027260i

[ACS Full Text ], [CAS], Google Scholar

280

Ground- and Excited-State Proton Transfer in Anthocyanins: From Weak Acids to Superphotoacids

Moreira, Paulo F., Jr.; Giestas, Leticia; Yihwa, Chang; Vautier-Giongo, Carolina; Quina, Frank H.; Macanita, Antonio L.; Lima, Joao C.

Journal of Physical Chemistry A (2003), 107 (21), 4203-4210CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

Malvidin-3,5-diglucoside (malvin), cyanidin-3,5-diglucoside (cyanin), and pelargonidin-3,5-diglucoside (pelargonin) are among the most representative anthocyanins because of their abundance in the most common red flowers and fruits. Anthocyanin color is directly affected by the pH-dependent chem. of the red (acid) form of these compds., while anthocyanin photostability is a function of the photophysics of the first excited singlet state. In the present work, we employ laser flash photolysis and picosecond time-correlated single-photon counting to det. the dynamics of the proton-transfer reactions of these three anthocyanins in the ground [deprotonation rate consts., kd = 1.3 × 106 s-1 (pelargonin), 1.8 × 106 s-1 (cyanin), and 3.8 × 106 s-1 (malvin)] and first excited singlet state [deprotonation rate consts., kd = 4.3 × 1010 s-1 (pelargonin), 4.0 × 1010 s-1 (cyanin), and 1.6 × 1011 s-1 (malvin)], resp. The ground- and excited-state proton-transfer rate consts. for anthocyanins and for photoacids of the naphthol type are found to correlate with an empirical parameter related to the ionic character of the dissociable OH bond. The present results show that the typically weak fluorescence of the flavylium cation form of anthocyanins is due primarily to competitive ultrafast, adiabatic proton transfer to water. This process is highly efficient as an energy-wasting mechanism, as would be required by an in vivo role such as protection of plant tissues from potentially deleterious excess radiant energy.

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281

Lima, J. C. ; Abreu, I. ; Brouillard, R. ; Macanita, A. L. Kinetics of Ultra-Fast Excited State Proton Transfer from 7-Hydroxy-4-Methylflavylium Chloride to Water. Chem. Phys. Lett. 1998, 298 , 189– 195, DOI: 10.1016/S0009-2614(98)01199-3

[Crossref], [CAS], Google Scholar

281

Kinetics of ultra-fast excited state proton transfer from 7-hydroxy-4-methylflavylium chloride to water

Lima, J. C.; Abreu, Isabel; Brouillard, Raymond; Macanita, Antonio L.

Chemical Physics Letters (1998), 298 (1-3), 189-195CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)

Excited state proton transfer from 7-hydroxy-4-methylflavylium chloride to water is reported. From a modified anal. of picosecond time-resolved fluorescence data (not using the lifetime of a parent compd.), all rate consts. were detd.: the deprotonation rate const. of the flavylium cation, kd=1.4×1011 s-1, the protonation rate const. of the base form, kp=2.3×1010 L mol-1 s-1 and the reciprocal fluorescence lifetimes of these species, kAH+=7.8×109 s-1 (τAH+=128 ps) and kA=7.6×109 s-1 (τA=132 ps), in water, at 20°. The value of kd is the largest measured value for an intermol. proton transfer (to water).

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282

Freitas, A. A. ; Quina, F. H. ; Macanita, A. A. L. Femtosecond and Temperature-Dependent Picosecond Dynamics of Ultrafast Excited-State Proton Transfer in Water-Dioxane Mixtures. J. Phys. Chem. A 2014, 118 , 10448– 10455, DOI: 10.1021/jp504189m

[ACS Full Text ], [CAS], Google Scholar

282

Femtosecond and Temperature-Dependent Picosecond Dynamics of Ultrafast Excited-State Proton Transfer in Water-Dioxane Mixtures

Freitas, Adilson A.; Quina, Frank H.; Macanita, Antonio A. L.

Journal of Physical Chemistry A (2014), 118 (45), 10448-10455CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

Synthetic flavylium salts like the 7-hydroxy-4-methylflavylium (HMF) cation were used as prototypes to study the chem. and photochem. of anthocyanins, the major group of water-sol. pigments in the plant kingdom. A combination of fluorescence upconversion with femtosecond time resoln. and time-correlated single photon counting (TCSPC) with picosecond time resoln. were employed to study in details the excited-state proton transfer (ESPT) of HMF in water and in binary water/1,4-dioxane mixts. TCSPC measurements as a function of temp. provide activation parameters for all of the individual rate consts. involved in the proton transfer, including those for dissocn. and recombination of the geminate excited base-proton pair (A*···H+) that can be detected in the water/dioxane mixts. (but not in water). Unlike the other rate consts., the deprotonation rate const. kd shows a non-Arrhenius dependence on temp. in both water and water/dioxane mixts. At low temps. kd is close to the dielec. relaxation rate of the solvent with a barrier of ∼8 kJ mol-1, suggesting that the solvent reorganization is the rate-limiting step. At higher temps. (>30 °C) the proton transfer process is nearly barrierless and solvent-dependent. Fluorescence upconversion results in H2O, D2O, and water/dioxane mixts. confirm the two-step model for the ESPT of HMF and provide addnl. details of the early events prior to the onset of proton transfer, attributed to conformational relaxation and solvent reaccommodation around the initially formed excited state. The results are consistent with DFT calcns. that indicate that charge redistribution occurs after rather than prior to the onset of the ESPT process.

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283

Pina, F. ; Melo, M. J. ; Santos, H. ; Lima, J. C. ; Abreu, I. ; Ballardini, R. ; Maestri, M. Excited State Proton Transfer in Synthetic Flavylium Salts: 4-Methyl-7-Hydroxyflavylium and 4 ',7-Dihydroxyflavylium - Example of a Four-Level Molecular Device to Invert the Population of the Excited State. New J. Chem. 1998, 22 , 1093– 1098, DOI: 10.1039/a801774c

[Crossref], [CAS], Google Scholar

283

Excited state proton transfer in synthetic flavylium salts: 4-methyl-7-hydroxyflavylium and 4',7-dihydroxyflavylium. Example of a four-level molecular device to invert the population of the excited state

Pina, Fernando; Joao Melo, Maria; Santos, Helena; Carlos Lima, Joao; Abreu, Isabel; Ballardini, Roberto; Maestri, Mauro

New Journal of Chemistry (1998), 22 (10), 1093-1098CODEN: NJCHE5; ISSN:1144-0546. (Royal Society of Chemistry)

The excited state proton transfer (ESPT) obsd. in the compds. 4-methyl-7-hydroxyflavylium and 4',7-dihydroxyflavylium is described, the results are quant. interpreted on the basis of the A. Weller approach. ESPT is esp. efficient in the case of 4-methyl-7-hydroxyflavylium. For pH>2, proton recombination in the excited state does not occur and the yield of the adiabatic formation of excited base (A*) through the excited acid (AH+*) is 0.93. This result compares with 0.45 for 4',7-dihydroxyflavylium under identical conditions. The use of adiabatic proton transfer to obtain the inversion of the population of the excited state is discussed.

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284

Freitas, A. A. ; Silva, C. P. ; Silva, G. T. M. ; Macanita, A. L. ; Quina, F. H. Ground- and Excited-State Acidity of Analogs of Red Wine Pyranoanthocyanins. Photochem. Photobiol. 2018, 94 , 1086– 1091, DOI: 10.1111/php.12944

[Crossref], [PubMed], [CAS], Google Scholar

284

Ground- and Excited-State Acidity of Analogs of Red Wine Pyranoanthocyanins,

Freitas, Adilson A.; Silva, Cassio Pacheco; Silva, Gustavo Thalmer M.; Macanita, Antonio L.; Quina, Frank H.

Photochemistry and Photobiology (2018), 94 (6), 1086-1091CODEN: PHCBAP; ISSN:0031-8655. (Wiley-Blackwell)

Pyranoflavylium cations are synthetic analogs contg. the same basic chromophore as the pyranoanthocyanins that form in red wine during maturation and are responsible for its final color. Detn. of the ground- and excited-state acidities for a series of eight substituted hydroxy pyranoflavylium cations shows that they are weak acids in the ground state (pKa ranging from 3.4 to 4.4 in aq. buffer soln.), but substantially more acidic in the first excited singlet state (pKa* ranging from ca. 0.2 to 0.7 in 30% methanol-water). Unlike the ground-state acidities, which show no obvious trend with electronic effects of the substituents, the excited-state pKa* values correlate well with Hammett sigma parameters for the substituents on the pyranoflavylium chromophore. This difference in the transmission of electronic effects between ground and excited state is reflected in the localization of the HOMO of the cation and conjugate base in distinct regions of the chromophore as compared to delocalization of the LUMO over the entire mol. The current results provide further support for the conclusion that excited-state proton transfer is the dominant deactivation pathway for the pyranoflavylium cation excited singlet state in aq. or aq.-org. media and presumably for pyranoanthocyanins as well.

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Freitas, A. A. ; Silva, C. P. ; Silva, G. T. M. ; Macanita, A. L. ; Quina, F. H. From Vine to Wine: Photophysics of a Pyranoflavylium Analog of Red Wine Pyranoanthocyanins. Pure Appl. Chem. 2017, 89 , 1761– 1767, DOI: 10.1515/pac-2017-0411

[Crossref], [CAS], Google Scholar

285

From vine to wine: photophysics of a pyranoflavylium analog of red wine pyranoanthocyanins

Freitas, Adilson A.; Silva, Cassio Pacheco; Silva, Gustavo Thalmer M.; Macanita, Antonio L.; Quina, Frank H.

Pure and Applied Chemistry (2017), 89 (12), 1761-1767CODEN: PACHAS; ISSN:0033-4545. (Walter de Gruyter, Inc.)

In the ground state, the p-methoxyphenyl-substituted pyranoflavylium cation I, prepd. by the reaction of the 5,7-dihydroxy-4-methylflavylium cation with p-methoxybenzaldehyde, is a weak acid (pKa=3.7±0.1). In its lowest excited singlet state, I is a moderate photoacid (pKa*=0.67) in 30% methanol-water acidified with trifluoroacetic acid (TFA). In comparison to anthocyanins and 7-hydroxyflavylium cations, the photoacidity of I is much less pronounced and the rate of proton loss from the excited acid form of I much slower (by a factor of up to 100). In 50% ethanol:0.10 mol dm-3 HClO4, the excited state of the acid form of I undergoes fast (12 ps) initial relaxation (potentially in the direction of an intramol. charge transfer state), followed by much slower (340 ps) adiabatic deprotonation to form the excited base. The excited base in turn exhibits a moderately fast relaxation (70 ps), consistent with solvent hydrogen-bond reorganization times, followed by slower but efficient decay (1240 ps) back to the ground state. As in uncomplexed anthocyanins and 7-hydroxyflavylium cations, the photophys. behavior of I points to excited state proton transfer as the dominant excited state deactivation pathway of pyranoanthocyanins, consistent with relatively good photostability of natural pyranoanthocyanins.

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286

Silva, G. T. M. ; Thomas, S. S. ; Silva, C. P. ; Schlothauer, J. C. ; Baptista, M. S. ; Freitas, A. A. ; Bohne, C. ; Quina, F. H. Triplet Excited States and Singlet Oxygen Production by Analogs of Red Wine Pyranoanthocyanins. Photochem. Photobiol. 2019, 95 , 176– 182, DOI: 10.1111/php.12973

[Crossref], [PubMed], [CAS], Google Scholar

286

Triplet Excited States and Singlet Oxygen Production by Analogs of Red Wine Pyranoanthocyanins

Silva, Gustavo Thalmer M.; Thomas, Suma S.; Silva, Cassio Pacheco; Schlothauer, Jan C.; Baptista, Mauricio S.; Freitas, Adilson A.; Bohne, Cornelia; Quina, Frank H.

Photochemistry and Photobiology (2019), 95 (1), 176-182CODEN: PHCBAP; ISSN:0031-8655. (Wiley-Blackwell)

During the maturation of red wines, the anthocyanins of grapes are transformed into pyranoanthocyanins, which possess a pyranoflavylium cation as their basic chromophore. Photophys. properties of the singlet and triplet excited states of a series of synthetic pyranoflavylium cations were detd. at room temp. in acetonitrile soln. acidified with 0.10 mol dm-3 trifluoroacetic acid (TFA, to inhibit competitive excited state proton transfer) and at 77 K in a rigid TFA-acidified isopropanol glass. In soln., the triplet states of these pyranoflavylium cations are efficiently quenched by mol. oxygen, resulting in sensitized formation of singlet oxygen, as confirmed by direct detection of the triplet-state decay by laser flash photolysis and of singlet oxygen monomol emission in the near IR. The strong visible light absorption, the relatively small singlet-triplet energy differences, the excited state redox potentials and the reasonably long lifetimes of pyranoflavylium triplet states in the absence of mol. oxygen suggest that they might be useful as triplet sensitizers and/or as cationic redox initiators in polar aprotic solvents like acetonitrile.

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287

Lakowicz, J. R. Principles of Fluorescence Spectroscopy; Springer: New York, 2006; pp 623– 673.

288

Czerney, P. ; Graness, G. ; Birckner, E. ; Vollmer, F. ; Rettig, W. Molecular Engineering of Cyanin-Type Fluorescent and Lases-Dyes. J. Photochem. Photobiol., A 1995, 89 , 31– 36, DOI: 10.1016/1010-6030(94)04018-W

[Crossref], [CAS], Google Scholar

288

Molecular engineering of cyanine-type fluorescent and laser dyes

Czerney, Peter; Graness, Gerhard; Birckner, Eckhard; Vollmer, Friedrich; Rettig, Wolfgang

Journal of Photochemistry and Photobiology, A: Chemistry (1995), 89 (1), 31-6CODEN: JPPCEJ; ISSN:1010-6030. (Elsevier)

The absorption and emission characteristics of several bis(dialkylamino)benzopyrylium dyes are compared, and their very different fluorescence quantum yields are correlated with the calcd. energies of the lowest excited states of twisted cyanine dyes. The latter are models for selectively bridged compds. The laser performance of the dyes is described and compared with well-known laser dyes. The 4-(2-carboxyphenyl)-substituted pyrylium salts are considerably more stable than the unsubstituted compds.

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289

Lindauer, H. ; Czerney, P. ; Mohr, G. J. ; Grummt, U.-W. New near Infrared Absorbing Acidochromic Dyes and Their Application in Sensor Techniques. Dyes Pigm. 1994, 26 , 229– 235, DOI: 10.1016/0143-7208(94)80038-3

[Crossref], [CAS], Google Scholar

289

New near infrared absorbing acidochromic dyes and their application in sensor techniques

Lindauer, Heike; Czerney, Peter; Mohr, Gerhard J.; Grummt, Ulrich-W.

Dyes and Pigments (1994), 26 (3), 229-35CODEN: DYPIDX; ISSN:0143-7208. (Elsevier)

Two new acidochromic styrylcyanines and one new benzopyrylotrimethinium dye were described. Their visible and near-IR absorption spectra were recorded as a function of pH in fluid soln. and embedded in polymer layers. The layers proved to be useful as pH sensors.

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Rettig, W. ; Majenz, W. ; Lapouyade, R. ; Haucke, F. Multidimensional Photochemistry in Flexible Dye Systems. J. Photochem. Photobiol., A 1992, 62 , 415– 427, DOI: 10.1016/1010-6030(92)85068-6

[Crossref], [CAS], Google Scholar

290

Multidimensional photochemistry in flexible dye systems

Rettig, Wolfgang; Majenz, Wilfried; Lapouyade, Rene; Haucke, Guenter

Journal of Photochemistry and Photobiology, A: Chemistry (1992), 62 (3), 415-27CODEN: JPPCEJ; ISSN:1010-6030.

The photophysics of many flexible dye systems can be understood on the basis of adiabatic photoreactions to emissive or nonemissive product states. Nonemissive product states lead to fluorescence quenching and are often the reason for what is conventionally called internal conversion. For compds. with several flexible bonds, competing photoreaction pathways can exist. This is shown for the example of benzopyrylium dyes and for donor-acceptor-stilbenes. Chem. bridging of bonds and/or substituent changes can control the competition between the various channels. This opens a new view on the multidimensional nature of the excited-state hypersurfaces and gives access to control dye properties by mol. engineering. Thirty-eight refs.

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Chen, H. ; Dong, B. ; Tang, Y. ; Lin, W. A Unique "Integration" Strategy for the Rational Design of Optically Tunable near-Infrared Fluorophores. Acc. Chem. Res. 2017, 50 , 1410– 1422, DOI: 10.1021/acs.accounts.7b00087

[ACS Full Text ], [CAS], Google Scholar

291

A Unique "Integration" Strategy for the Rational Design of Optically Tunable Near-Infrared Fluorophores

Chen, Hua; Dong, Baoli; Tang, Yonghe; Lin, Weiying

Accounts of Chemical Research (2017), 50 (6), 1410-1422CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review. Fluorescence imaging is a rapidly growing technique for noninvasive imaging of biol. mols. and processes with high spatial and temporal resoln. For effective biol. imaging, it is essential and important to develop robust fluorescent dyes, in particular, near-IR (NIR) fluorescent dyes with favorable optical properties. Compared with the visible light emitting dyes, NIR dyes have relatively longer emission wavelengths (650-900 nm) with lower energy and are advantageous as imaging agents owing to the min. photodamage of NIR light to biol. samples, deep penetration into tissues, and low interference from autofluorescence of biomols. Although great efforts have been devoted to engineer NIR fluorophores, it is still very challenging to regulate their photophys. properties as they often lack optically tunable mechanisms, and this shortcoming considerably restricts the realization of their full potential. Consequently, the rational design of small-mol. optically tunable NIR fluorophores is of high priority and great value. In general, two key characteristics are indispensable for designing excellent optically tunable NIR fluorescent dyes. First, NIR fluorescent dyes should display the maximal absorption and emission located in the NIR region and also have the prominent properties including excellent fluorescence quantum yields, large Stokes shifts, good chem. stability and photostability, low cytotoxicity, and desirable compatibility with biol. systems. Second, in principle, functional NIR dyes should also possess optically tunable groups, which can be easily modified to afford responsive sites for the targets of interest. With these considerations in mind, in this Account, the authors described a unique "integration" strategy for judicious design of the optically tunable NIR fluorophores, which are an intuitive combination of the traditional NIR dyes and the optically tunable mechanisms in the visible light emissive dyes. Thus, the versatile strategy may allow not only retention of the NIR emission properties of NIR dyes but also inheritance of the optically tunable mechanisms from the visible light emissive dyes. By the unique integration strategy, a built-in optically tunable group is strategically installed into the traditional NIR fluorescent dyes to directly tune their optical properties. Herein, the authors present a concise review of the rational design strategy and biol. applications of small-mol. optically tunable NIR fluorescent dyes via the unique integration strategy, and the authors focused mainly on the work and some representative examples from other groups based on the NIR platforms. This Account includes the detailed integration strategy of each class of the NIR fluorescent dyes, the development of their derivs., and their imaging applications in living systems.

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Zhou, L. ; Wang, Q. ; Tan, Y. ; Lang, M. J. ; Sun, H. ; Liu, X. Rational Development of near-Infrared Fluorophores with Large Stokes Shifts, Bright One-Photon, and Two-Photon Emissions for Bioimaging and Biosensing Applications. Chem. - Eur. J. 2017, 23 , 8736– 8740, DOI: 10.1002/chem.201701365

[Crossref], [PubMed], [CAS], Google Scholar

292

Rational Development of Near-Infrared Fluorophores with Large Stokes Shifts, Bright One-Photon, and Two-Photon Emissions for Bioimaging and Biosensing Applications

Zhou, Liyi; Wang, Qianqian; Tan, Yi; Lang, Matthew J.; Sun, Hongyan; Liu, Xiaogang

Chemistry - A European Journal (2017), 23 (36), 8736-8740CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

Fluorophores with near-IR emissions play a crucial role in numerous bioimaging and biosensing applications, owing to their deep penetration depths, low auto-fluorescence, and minimal tissue damages. Herein, the rational development of a new class of near-IR fluorophores (I)(R=-NH2, -N(CH3)2, -H, -N3) with bright one-photon and two-photon emissions at ≈740 nm, large Stokes shifts (≈80 nm), significant two-photon action absorption cross-section (≈185 GM at 820 nm), excellent water soly., outstanding photostability, and low toxicity is reported. Their biol. applications in mitochondrial labeling, deep tissue imaging, and H2S detection in live cells and mice are also demonstrated. In addn., a rational design strategy for enlarging the Stokes shifts and enhancing two-photon emissions of these fluorophores is presented. These fluorophores I will serve as a useful platform for developing novel imaging and sensing agents, and the design methodologies will inspire the mol. engineering of abundant high-performance near-IR fluorophores.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsVChsL0%253D&md5=3f466a1bd75162753a13b80d044ce804

293

Chen, H. ; Lin, W. ; Jiang, W. ; Dong, B. ; Cui, H. ; Tang, Y. Locked-Flavylium Fluorescent Dyes with Tunable Emission Wavelengths Based on Intramolecular Charge Transfer for Multi-Color Ratiometric Fluorescence Imaging. Chem. Commun. 2015, 51 , 6968– 6971, DOI: 10.1039/C5CC01242B

[Crossref], [PubMed], [CAS], Google Scholar

293

Locked-flavylium fluorescent dyes with tunable emission wavelengths based on intramolecular charge transfer for multi-color ratiometric fluorescence imaging

Chen, Hua; Lin, Weiying; Jiang, Wenqing; Dong, Baoli; Cui, Haijun; Tang, Yonghe

Chemical Communications (Cambridge, United Kingdom) (2015), 51 (32), 6968-6971CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

A new class of locked-flavylium fluorophores with tunable emission wavelengths based on intramol. charge transfer were designed, synthesized, and evaluated. The optical studies indicate that sensor LF3 can display an intriguing character, fluorescence ratiometric response in 3 channels by tuning the ICT efficiencies.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksFWisrs%253D&md5=f8f8dacff1bb6494effd97fe5220d7e2

294

Pessêgo, M. ; Gago, S. ; Basílio, N. ; Laia, C. A. T. ; Jorge Parola, A. ; Lima, J. C. ; Pina, F. Hiding and Unveiling Trans-Chalcone in a Constrained Derivative of 4′,7-Dihydroxyflavylium in Water: A Versatile Photochromic System. Org. Biomol. Chem. 2017, 15 , 338– 347, DOI: 10.1039/C6OB01607C

[Crossref], [PubMed], [CAS], Google Scholar

294

Hiding and unveiling trans-chalcone in a constrained derivative of 4',7-dihydroxyflavylium in water: a versatile photochromic system

Pessego, Marcia; Gago, Sandra; Basilio, Nuno; Laia, Cesar A. T.; Jorge Parola, A.; Lima, Joao C.; Pina, Fernando

Organic & Biomolecular Chemistry (2017), 15 (2), 338-347CODEN: OBCRAK; ISSN:1477-0520. (Royal Society of Chemistry)

A structurally constrained deriv. of 4',7-dihydroxyflavylium was studied in aq. soln. and in CTAB micelles by pH jumps, flash photolysis and continuous irradn. with spectroscopic details assessed as well by theor. calcns. In water, up to pH = 8, the compd. shows only acid base chem. with deprotonation of the flavylium cation to form a quinoidal base that further deprotonates with pKas of 4.8 and 7.4. In the basic region, unprotonated trans-chalcones are formed. No neutral trans-chalcone (Ct) is formed in water preventing the establishment of the well-known photochromism involving photoisomerization of this species with subsequent formation of the flavylium cation. Addn. of 0.02 M CTAB drastically changes the mole fraction distribution of species, leading to the formation of Ct (χCt = 1 at pH = 5) and unveiling a photochromic behavior with a pH-tunable color contrast in a large pH range (2 < pH < 8). The Ct species can be hidden again (irreversibly) upon addn. of α-cyclodextrin that disrupts the CTAB micelles, reverting the system to its initial mole fraction distribution of species. These supramol. inputs work atop the mol. reaction networks by modifying their species' mole fraction distribution.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1Gnsb%252FM&md5=a94a40ea4a6ca3e0e0c64af075563e89

295

Kopainsky, B. ; Qiu, P. ; Kaiser, W. ; Sens, B. ; Drexhage, K. H. Lifetime, Photostability, and Chemical-Structure of Ir Heptamethine Cyanine Dyes Absorbing Beyond 1 Mu-Mm. Appl. Phys. B: Photophys. Laser Chem. 1982, 29 , 15– 18, DOI: 10.1007/BF00694363

[Crossref], [CAS], Google Scholar

295

Lifetime, photostability, and chemical structure of IR heptamethine cyanine dyes absorbing beyond 1μm

Kopainsky, B.; Qiu, P.; Kaiser, W.; Sens, B.; Drexhage, K. H.

Applied Physics B: Photophysics and Laser Chemistry (1982), B29 (1), 15-18CODEN: APPCDL; ISSN:0721-7269.

Optical absorption, S1 lifetime, and photostability are investigated for a series of heptamethine IR dyes and related to chem. structure. The high photostability of several dyes and the large range of S1 lifetimes make these dyes very interesting for IR dye lasers and for IR mode-locked laser systems.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL38XmtVGgu7k%253D&md5=49508440b6267da1b97d36fbe1d66516

296

Cosco, E. D. ; Caram, J. R. ; Bruns, O. T. ; Franke, D. ; Day, R. A. ; Farr, E. P. ; Bawendi, M. G. ; Sletten, E. M. Flavylium Polymethine Fluorophores for near- and Shortwave Infrared Imaging. Angew. Chem., Int. Ed. 2017, 56 , 13126– 13129, DOI: 10.1002/anie.201706974

[Crossref], [CAS], Google Scholar

296

Flavylium Polymethine Fluorophores for Near- and Shortwave Infrared Imaging

Cosco, Emily D.; Caram, Justin R.; Bruns, Oliver T.; Franke, Daniel; Day, Rachael A.; Farr, Erik P.; Bawendi, Moungi G.; Sletten, Ellen M.

Angewandte Chemie, International Edition (2017), 56 (42), 13126-13129CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

Bright fluorophores in the near-IR and shortwave IR (SWIR) regions of the electromagnetic spectrum are essential for optical imaging in vivo. The authors used a 7-dimethylamino flavylium heterocycle to construct a panel of novel red shifted polymethine dyes, with emission wavelengths from 680 to 1045 nm. Photophys. characterization revealed that the 1- and 3-methine dyes display enhanced photostability and the 5- and 7-methine dyes exhibit exceptional brightness for their resp. spectral regions. A micelle formulation of the 7-methine facilitated SWIR imaging in mice. This report presents the first polymethine dye designed and synthesized for SWIR in vivo imaging.

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297

Cherepy, N. J. ; Smestad, G. P. ; Gratzel, M. ; Zhang, J. Z. Ultrafast Electron Injection: Implications for a Photoelectrochemical Cell Utilizing an Anthocyanin Dye-Sensitized Tio2 Nanocrystalline Electrode. J. Phys. Chem. B 1997, 101 , 9342– 9351, DOI: 10.1021/jp972197w

[ACS Full Text ], [CAS], Google Scholar

297

Ultrafast Electron Injection: Implications for a Photoelectrochemical Cell Utilizing an Anthocyanin Dye-Sensitized TiO2 Nanocrystalline Electrode

Cherepy, Nerine J.; Smestad, Greg P.; Graetzel, Michael; Zhang, Jin Z.

Journal of Physical Chemistry B (1997), 101 (45), 9342-9351CODEN: JPCBFK; ISSN:1089-5647. (American Chemical Society)

A photoelectrochem. cell utilizing flavonoid anthocyanin dyes extd. from blackberries, along with colloidal TiO2 powder, is shown to convert sunlight to elec. power at an efficiency of 0.56% under full sun. Fluorescence quenching is obsd. for the excited state of the TiO2-adsorbed anthocyanin dye, cyanin, and the photocurrent spectrum correlates well with the optical absorption of the cyanin-sensitized TiO2 nanocryst. film. The incident photon-to-current efficiency of 19% at the peak of the visible absorption band of the dye, the open-circuit voltages of 0.5-0.4 V, and short-circuit photocurrents of 1.5-2.2 mA/cm2 are remarkable for such a simple system and suggest efficient charge carrier injection. The ultrafast excited-state dynamics of cyanin in soln. are compared with those of surface-adsorbed cyanin on TiO2 and ZrO2 colloids, as well as complexed with Al(III) ions. A transient absorption signal with a risetime of <100 fs for cyanin-sensitized TiO2 nanoparticles is assigned to electrons injected from the dye to TiO2. This signal is fit to a double-exponential decay with time consts. of 0.52 and 67 ps. The 0.52 ps component is due to trapping of conduction band electrons or to fast direct recombination with the dye cation, while the 67 ps decay is attributed to trap state mediated indirect recombination. In contrast, stimulated emission with a 2.6 ps decay time is obsd. for cyanin in soln., cyanin on ZrO2, and cyanin complexed with Al(III) ions. When compared to the photon-to-current efficiency measured for the solar cell, the efficiency estd. from the injection and recombination rate consts. suggests that electron recapture by the redox mediator and light screening mechanisms may limit the efficiency of the cell.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmvVaktrw%253D&md5=9bb97f9459ef4b1fa419f963c595522a

298

Calogero, G. ; Sinopoli, A. ; Citro, I. ; Di Marco, G. ; Petrov, V. ; Diniz, A. M. ; Parola, A. J. ; Pina, F. Synthetic Analogues of Anthocyanins as Sensitizers for Dye-Sensitized Solar Cells. Photochem. Photobiol. Sci. 2013, 12 , 883– 894, DOI: 10.1039/c3pp25347c

[Crossref], [PubMed], [CAS], Google Scholar

298

Synthetic analogues of anthocyanins as sensitizers for dye-sensitized solar cells

Calogero, Giuseppe; Sinopoli, Alessandro; Citro, Ilaria; Di Marco, Gaetano; Petrov, Vesselin; Diniz, Ana M.; Parola, A. Jorge; Pina, Fernando

Photochemical & Photobiological Sciences (2013), 12 (5), 883-894CODEN: PPSHCB; ISSN:1474-905X. (Royal Society of Chemistry)

Seven flavylium salt dyes were employed for the first time as sensitizers for dye-sensitized solar cells (DSSCs). The theor. and exptl. wavelengths of the max. absorbances, the HOMO and LUMO energy levels, the coeffs., the oscillator strengths and the dipole moments are calcd. for these synthetic dyes. The introduction of a donor group in the flavylium mol. structure was investigated. Photophys. and photoelectrochem. measurements showed that some of these synthetic analogs of anthocyanins are very promising for DSSC applications. The best performance was obtained by a DSSC based on the novel compd. 7-(N,N-diethylamino)-3',4'-dihydroxyflavylium which produced a 2.15% solar energy-to-electricity conversion efficiency, under AM 1.5 irradn. (100 mW cm-2) with a short-circuit c.d. (Jsc) of 12.0 mA cm-2, a fill factor of 0.5 and an open-circuit voltage (Voc) of 0.355 V; its incident photocurrent efficiency of 51% at the peak of the visible absorption band of the dye is remarkable. Our results demonstrated that the substitution of a hydroxylic group with a diethylamine unit in position 7 of ring A of the flavylium backbone expanded the π-conjugation in the dye and thus resulted in a higher absorption in the visible region and is advantageous for effective electron injection from the dye into the conduction band of TiO2.

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299

Pinto, A. L. ; Cruz, L. ; Gomes, V. ; Cruz, H. ; Calogero, G. ; de Freitas, V. ; Pina, F. ; Parola, A. J. ; Carlos Lima, J. Catechol Versus Carboxyl Linkage Impact on Dssc Performance of Synthetic Pyranoflavylium Salts. Dyes Pigm. 2019, 170 , 107577, DOI: 10.1016/j.dyepig.2019.107577

[Crossref], [CAS], Google Scholar

299

Catechol versus carboxyl linkage impact on DSSC performance of synthetic pyranoflavylium salts

Pinto, Ana Lucia; Cruz, Luis; Gomes, Vania; Cruz, Hugo; Calogero, Giuseppe; de Freitas, Victor; Pina, Fernando; Parola, A. Jorge; Carlos Lima, J.

Dyes and Pigments (2019), 170 (), 107577CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

Anthocyanins are the main polyphenolic dyes found in young red wines, which are transformed into more stable structures such as pyranoanthocyanins, during wine ageing and maturation. While anthocyanins practically lose their red color between pH 1 and 5, as a result of the formation of colorless hemiketals, pyranoanthocyanins practically do not change their color intensity. For that they constitute a photosensitizer family with great potential for bio-inspired dye-sensitized solar cells (DSSCs). In this work, a series of pyranoanthocyanin derivs. were designed, synthesized and applied for the first time as dye sensitizers in DSSCs. A relation was established between dye structure and cell efficiency. Specifically, the influence of different linker units, carboxyl and catechol, was studied in terms of their influence in the various parameters related to DSSC efficiency. The presence of the catechol unit was shown to be essential for efficient electron injection of the dye into the TiO2 semiconductor, since carboxylic units showed a deleterious effect in electron injection due to their electron withdrawing character. An overall efficiency of 1.15% was obtained for the best performing compd., 10-catecholpyrano-3',4',5,7-tetrahydroxyflavylium, with no further optimization.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtVOjsLzO&md5=a6c031a19e4b6e98f31debcb9cc329db

300

Phan, K. ; De Meester, S. ; Raes, K. ; De Clerck, K. ; Van Speybroeck, V. A Comparative Study on the Photophysical Properties of Anthocyanins and Pyranoanthocyanins. Chem. - Eur. J. 2021, 27 , 5956– 5971, DOI: 10.1002/chem.202004639

[Crossref], [PubMed], [CAS], Google Scholar

300

A Comparative Study on the Photophysical Properties of Anthocyanins and Pyranoanthocyanins

Phan, Kim; De Meester, Steven; Raes, Katleen; De Clerck, Karen; Van Speybroeck, Veronique

Chemistry - A European Journal (2021), 27 (19), 5956-5971CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

Anthocyanins and pyranoanthocyanins are flavonoids that are present in various food products (e.g., fruit, vegetables, wine, etc.). The large chem. diversity amongst these mols. leads to compd.-specific properties such as color and stability towards external conditions. These properties are also attractive for food and non-food applications. The photophys. exptl. characterization is not easy as this generally demands advanced anal. techniques along with optimized sepn. procedures. Mol. modeling can provide insights into the fundamental understanding of the photophys. properties of these compds. in a uniform way for a broad set of compds. However, the current literature is quite fragmented on this topic. Herein, a large set of 140 naturally derived anthocyanins was evaluated in a systematic way with three functionals (B3LYP, PBE0, and CAM-B3LYP). The accuracy of these functionals was detd. with exptl. literature λmax,vis values. In addn. to λmax,vis values, time-dependent (TD)-DFT calcns. also provided oscillator strengths, molar absorption coeffs., and orbital energies, which define whether specific natural anthocyanin-based compds. can be deployed in food and non-food applications such as food additives/colorants, textile dyeing, anal. stds., and dye-sensitized solar cells (DSSCs).

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXlslShtL8%253D&md5=fe9b1a485545dcf4999e964b546e9e9d

301

Blanco-Gómez, A. ; Cortón, P. ; Barravecchia, L. ; Neira, I. ; Pazos, E. ; Peinador, C. ; García, M. D. Controlled Binding of Organic Guests by Stimuli-Responsive Macrocycles. Chem. Soc. Rev. 2020, 49 , 3834– 3862, DOI: 10.1039/D0CS00109K

[Crossref], [PubMed], [CAS], Google Scholar

301

Controlled binding of organic guests by stimuli-responsive macrocycles

Blanco-Gomez, Arturo; Corton, Pablo; Barravecchia, Liliana; Neira, Iago; Pazos, Elena; Peinador, Carlos; Garcia, Marcos D.

Chemical Society Reviews (2020), 49 (12), 3834-3862CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Synthetic supramol. chem. pursues not only the construction of new matter, but also control over its inherently dynamic behavior. In this context, classic host-guest chem., based on the development of a myriad of macrocyclic receptors with fine-tuned affinities and selectivities, has enormously contributed to the discovery of new chem. function under self-assembly conditions. In turn, the use of mol. switches as control units within host-guest assemblies opened the door for the regulation of their dynamic interactional behavior, which can be translated into controlled aggregation. In this review, we will focus on different strategies developed for the regulated binding of org. mols. by switchable macrocyclic hosts. As we will see, an appropriate design using stimuli-responsive versions of well-known org. receptors allows the mol. switches implemented within their structures to transform their regulated behavior from the mol. to the supramol. level.

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Grzelczak, M. ; Liz-Marzan, L. M. ; Klajn, R. Stimuli-Responsive Self-Assembly of Nanoparticles. Chem. Soc. Rev. 2019, 48 , 1342– 1361, DOI: 10.1039/C8CS00787J

[Crossref], [PubMed], [CAS], Google Scholar

302

Stimuli-responsive self-assembly of nanoparticles

Grzelczak, Marek; Liz-Marzan, Luis M.; Klajn, Rafal

Chemical Society Reviews (2019), 48 (5), 1342-1361CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

The capacity to respond or adapt to environmental changes is an intrinsic property of living systems that comprise highly-connected subcomponents communicating through chem. networks. The development of responsive synthetic systems is a relatively new research area that covers different disciplines, among which nanochem. brings conceptually new demonstrations. Esp. attractive are ligand-protected gold nanoparticles, which have been extensively used over the last decade as building blocks in constructing superlattices or dynamic aggregates, under the effect of an applied stimulus. To reflect the importance of surface chem. and nanoparticle core compn. in the dynamic self-assembly of nanoparticles, we provide here an overview of various available stimuli, as tools for synthetic chemists to exploit. Along with this task, the review starts with the use of chem. stimuli such as solvent, pH, gases, metal ions or biomols. It then focuses on phys. stimuli: temp., magnetic and elec. fields, as well as light. To reflect on the increasing complexity of current architectures, we discuss systems that are responsive to more than one stimulus, to finally encourage further research by proposing future challenges.

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Qu, D. H. ; Wang, Q. C. ; Zhang, Q. W. ; Ma, X. ; Tian, H. Photoresponsive Host-Guest Functional Systems. Chem. Rev. 2015, 115 , 7543– 7588, DOI: 10.1021/cr5006342

[ACS Full Text ], [CAS], Google Scholar

303

Photoresponsive Host-Guest Functional Systems

Qu, Da-Hui; Wang, Qiao-Chun; Zhang, Qi-Wei; Ma, Xiang; Tian, He

Chemical Reviews (Washington, DC, United States) (2015), 115 (15), 7543-7588CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review in which photoinduced capture and release of guests are discussed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjtV2ntLg%253D&md5=8035fafb9ab2fb3043d3113a4dc9f4b8

304

Ceroni, P. ; Credi, A. ; Venturi, M. Light to Investigate (Read) and Operate (Write) Molecular Devices and Machines. Chem. Soc. Rev. 2014, 43 , 4068– 4083, DOI: 10.1039/C3CS60400D

[Crossref], [PubMed], [CAS], Google Scholar

304

Light to investigate (read) and operate (write) molecular devices and machines

Ceroni, Paola; Credi, Alberto; Venturi, Margherita

Chemical Society Reviews (2014), 43 (12), 4068-4083CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. The development of multicomponent (supramol.) systems that can perform predetd. functions under external control - i.e., mol. devices - is a challenging task in chem. and a fascinating objective in the frame of a bottom-up approach to nanostructures. In this context light signals can be conveniently used both for supplying energy to the system and for probing its states and transformations. The aim of this tutorial review is to recall a few basic aspects of light-induced processes that can be used to "write" and "read" onto mol. and supramol. systems. These principles are illustrated through some examples of artificial mol. devices and machines taken from our work, which provide a flavor of current research. They are mol. and supramol. systems that operate and/or perform valuable functions by exploiting photoinduced energy- or electron-transfer processes, photoisomerization reactions, or photoinduced proton transfer. The choice of these examples was based on both their intrinsic importance for the referred topic and their educational value. In the last section of the review potential applications, limitations and future directions of the research in the field of artificial mol. devices and machines are also discussed.

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Szymanski, W. ; Beierle, J. M. ; Kistemaker, H. A. V. ; Velema, W. A. ; Feringa, B. L. Reversible Photocontrol of Biological Systems by the Incorporation of Molecular Photoswitches. Chem. Rev. 2013, 113 , 6114– 6178, DOI: 10.1021/cr300179f

[ACS Full Text ], [CAS], Google Scholar

305

Reversible Photocontrol of Biological Systems by the Incorporation of Molecular Photoswitches

Szymanski, Wiktor; Beierle, John M.; Kistemaker, Hans A. V.; Velema, Willem A.; Feringa, Ben L.

Chemical Reviews (Washington, DC, United States) (2013), 113 (8), 6114-6178CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. Photoswitches have been developed to control the conformation and activity of biomols. in a reversible manner. This review aims at providing a comprehensive and crit. literature review on reversible photocontrol of biomols.'structure and function with mol. photoswitches.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXms1Wjtbc%253D&md5=5e3785c5753c2f108e2c5ab1872e93c9

306

Steed, J. W.; Atwood, J. L. Supramolecular Chemistry; John Wiley & Sons, 2013.

307

Szejtli, J. Introduction and General Overview of Cyclodextrin Chemistry. Chem. Rev. 1998, 98 , 1743– 1753, DOI: 10.1021/cr970022c

[ACS Full Text ], [CAS], Google Scholar

307

Introduction and General Overview of Cyclodextrin Chemistry

Szejtli, Jozsef

Chemical Reviews (Washington, D. C.) (1998), 98 (5), 1743-1753CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review with 38 refs. on the actual or potential uses of CDs in pharmaceuticals, foods, cosmetics, chem. products and technologies.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXksV2itrw%253D&md5=fe0f94e1fe3e0ce3cd0fdc22f8f3d4b1

308

Connors, K. A. The Stability of Cyclodextrin Complexes in Solution. Chem. Rev. 1997, 97 , 1325– 1357, DOI: 10.1021/cr960371r

[ACS Full Text ], [CAS], Google Scholar

308

The Stability of Cyclodextrin Complexes in Solution

Connors, Kenneth A.

Chemical Reviews (Washington, D. C.) (1997), 97 (5), 1325-1357CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review with 497 refs. Physicochem. properties, binding equil. and kinetics, structures and stability, and pharmaceutical uses of cyclodextrin complexes are discussed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXksV2kurs%253D&md5=30f3b8061136f464fd59b0ab7abfaa2d

309

Crini, G. Review: A History of Cyclodextrins. Chem. Rev. 2014, 114 , 10940– 10975, DOI: 10.1021/cr500081p

[ACS Full Text ], [CAS], Google Scholar

309

Review: A History of Cyclodextrins

Crini, Gregorio

Chemical Reviews (Washington, DC, United States) (2014), 114 (21), 10940-10975CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A discussion of the history of cyclodextrins is presented, describing the 120 years from discovery to development to the process of application.

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Del Valle, E. M. M. Cyclodextrins and Their Uses: A Review. Process Biochem. 2004, 39 , 1033– 1046, DOI: 10.1016/S0032-9592(03)00258-9

[Crossref], [CAS], Google Scholar

310

Cyclodextrins and their uses: a review

Del Valle, E. M. Martin

Process Biochemistry (Oxford, United Kingdom) (2004), 39 (9), 1033-1046CODEN: PBCHE5; ISSN:1359-5113. (Elsevier Science Ltd.)

A review. Cyclodextrins are a family of cyclic oligosaccharides composed of α-(1,4) linked glucopyranose subunits. Cyclodextrins are useful mol. chelating agents. They possess a cage-like supramol. structure, which is the same as the structures formed from cryptands, calixarenes, cyclophanes, spherands and crown ethers. These compds. having supramol. structures carry out chem. reactions that involve intramol. interactions where covalent bonds are not formed between interacting mols., ions or radicals. The majority of all these reactions are of host-guest' type. Compared to all the supramol. hosts mentioned above, cyclodextrins are most important. Because of their inclusion complex forming capability, the properties of the materials with which they complex can be modified significantly. As a result of mol. complexation phenomena CDs are widely used in many industrial products, technologies and anal. methods. The negligible cytotoxic effects of CDs are an important attribute in applications such as rug carrier, food and flavors, cosmetics, packing, textiles, sepn. processes, environment protection, fermn. and catalysis.

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311

Dangles, O. ; Brouillard, R. A Spectroscopic Method Based on the Anthocyanin Copigmentation Interaction and Applied to the Quantitative Study of Molecular-Complexes. J. Chem. Soc., Perkin Trans. 2 1992, 2 , 247– 257, DOI: 10.1039/p29920000247

312

Yamada, T. ; Komiya, T. ; Akaki, M. Formation of an Inclusion Complex of Anthocyanin with Cyclodextrin. Agric. Biol. Chem. 1980, 44 , 1411– 1413, DOI: 10.1080/00021369.1980.10864141

[Crossref], [CAS], Google Scholar

312

Formation of an inclusion complex of anthocyanin with cyclodextrin

Yamada, Tetsuya; Komiya, Takashi; Akaki, Morio

Agricultural and Biological Chemistry (1980), 44 (6), 1411-13CODEN: ABCHA6; ISSN:0002-1369.

The addn. of β-cyclodextrin (β-CD) to solns. of callistephin (I), chrysanthemin (II), or nasunin (III) resulted in the fading of I and II, and this fading effect was greater with higher concns. of β-CD added. Addn. of α-CD had a smaller but significant fading effect in I and little, if any, in II. Addn. of amylase resulted in the fading only of I soln. There was no change in III solns. with addn. of α-CD, β-CD, or amylase. The fading reaction of anthocyanin must by based on the change of an oxonium ion into a pseudobase in the anthocyanidin moiety. This may be accomplished by the formation of an inclusion complex of anthocyanin with β-CD followed by the catalytic action of β-CD in changing the oxonium ion into the pseudobase. This is supported by an obsd. depression of pH and a small increment of absorbance in the UV region of I soln. with the addn. of β-CD. Under extremely acidic conditions the fading effect of both I and II in the presence of β-CD disappeared and the absorbance of both anthocyanin solns. instantly recovered to initial values obtained in the absence of β-CD, suggesting that the inclusion complex may protect anthocyanin from decompn. in spite of its labile pseudobase form.

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Dangles, O. ; Wigand, M. C. ; Brouillard, R. Anthocyanin Anti-Copigment Effect. Phytochemistry 1992, 31 , 3811– 3812, DOI: 10.1016/S0031-9422(00)97533-2

[Crossref], [CAS], Google Scholar

313

Anthocyanin anti-copigment effect

Dangles, O.; Wigand, M. C.; Brouillard, R.

Phytochemistry (1992), 31 (11), 3811-12CODEN: PYTCAS; ISSN:0031-9422.

By means of visible absorption spectrometry, it is shown that, in aq. solns. at pH 2 and 25°, callistephin (I) strongly interacts with β-cyclodextrin. The color loss, or absorption decrease in the visible range, which results from this interaction is mainly due to the encapsulation of I colorless forms into the β-cyclodextrin cavity. This phenomenon, which can lead to an almost complete discoloration if sufficient amts. of the macrocycle are added to I acidic solns., has been called the anti-copigment effect. The weak interaction taking place between I flavylium cation and β-cyclodextrin cannot oppose the almost inclusion of I colorless forms.

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314

Fernandes, A. ; Sousa, A. ; Azevedo, J. ; Mateus, N. ; de Freitas, V. Effect of Cyclodextrins on the Thermodynamic and Kinetic Properties of Cyanidin-3-O-Glucoside. Food Res. Int. 2013, 51 , 748– 755, DOI: 10.1016/j.foodres.2013.01.037

[Crossref], [CAS], Google Scholar

314

Effect of cyclodextrins on the thermodynamic and kinetic properties of cyanidin-3-O-glucoside

Fernandes, Ana; Sousa, Andre; Azevedo, Joana; Mateus, Nuno; de Freitas, Victor

Food Research International (2013), 51 (2), 748-755CODEN: FORIEU; ISSN:0963-9969. (Elsevier B.V.)

In this study, the effect of α and β-cyclodextrin on cyanidin-3-O-glucoside color was investigated by UV-visible absorption techniques. The equil. and kinetic consts. of the network of chem. reactions taking place in cyanidin-3-O-glucoside were also studied in water at 25 °C by UV-visible absorption techniques. The results showed that the addn. of β-cyclodextrin resulted in the fading of anthocyanin soln., and this fading effect was greater at higher pH. This anti-copigmentation effect is caused by the selective inclusion and stabilization of the anthocyanin colorless forms into the β-cyclodextrin cavity. Oppositely, no changes were obsd. in the cyanidin-3-O-glucoside absorption spectra with the addn. of α-cyclodextrin. Direct pH jump, from thermally equilibrated solns. at pH = 1.0 (flavylium cation, AH+), shows three kinetic processes: formation of the base A, hydration reaction to form the hemiketal B and the chalcone cis-trans isomerization (Cc-Ct). The results obtained clearly indicated that the equil. and kinetic consts. of the network of chem. reactions taking place in cyanidin-3-O-glucoside were affected by the presence of β-cyclodextrin. Mol. inclusion in the β-cyclodextrin cavity resulted in the increase of the isomerization obsd. rate const. (kobs) at pH 5.3 and in the increase of the hydration equil. const. Kh which is in agreement with the fading of the anthocyanin soln. For the macrocycle α-cyclodextrin, no significant changes were obsd. on the equil. and kinetic consts., which suggests that the inclusion of cyanidin-3-glucoside in the α-cyclodextrin's cavity is not favored.

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Fernandes, A. ; Ivanova, G. ; Bras, N. F. ; Mateus, N. ; Ramos, M. J. ; Rangel, M. ; de Freitas, V. Structural Characterization of Inclusion Complexes between Cyanidin-3–0-Glucoside and Beta-Cyclodextrin. Carbohydr. Polym. 2014, 102 , 269– 277, DOI: 10.1016/j.carbpol.2013.11.037

[Crossref], [PubMed], [CAS], Google Scholar

315

Structural characterization of inclusion complexes between cyanidin-3-O-glucoside and β-cyclodextrin

Fernandes, Ana; Ivanova, Galya; Bras, Natercia F.; Mateus, Nuno; Ramos, Maria J.; Rangel, Maria; de Freitas, Victor

Carbohydrate Polymers (2014), 102 (), 269-277CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

Inclusion complex formation between the multiple equil. forms of cyanidin-3-O-glucoside (cy3glc) and β-cyclodextrin (β-CD) was investigated using a combined approach of NMR spectroscopy and Mol. Dynamics simulation. Diffusion ordered NMR spectroscopy (DOSY) and study of nuclear Overhauser effects (NOE) were used to det. the selective intermol. interactions and structure of these complexes in aq. soln. The obsd. chem. shift displacements of resonance signals of protons from the interior of β-CD cavity and protons belonging to the hemiketal (B) and cis-chalcone forms (Cc), the diffusion measurements using DOSY and the NOE studies have anticipated the formation of an inclusion complex between these two forms and β-CD. The anal. of the NMR spectral data has shown no evidence of internal interaction between β-CD and the flavylium cation (AH+) or trans-chalcone (Ct) forms of cy3glc. The hemiketal formed a 1:1 inclusion complex with β-cyclodextrin in which the pyranic C ring is deeply included inside the β-CD cavity while B ring lies on the plane of the wider rim of β-CD. The structure of the complexes was also clarified through a theor. approach by Mol. Dynamics simulation.

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Dangles, O. ; Stoeckel, C. ; Wigand, M. C. ; Brouillard, R. Two Very Distinct Types of Anthocyanin Complexation: Copigmentation and Inclusion. Tetrahedron Lett. 1992, 33 , 5227– 5230, DOI: 10.1016/S0040-4039(00)79139-8

[Crossref], [CAS], Google Scholar

316

Two very distinct types of anthocyanin complexation: copigmentation and inclusion

Dangles, O.; Stoeckel, C.; Wigand, M. C.; Brouillard, R.

Tetrahedron Letters (1992), 33 (36), 5227-30CODEN: TELEAY; ISSN:0040-4039.

Some natural and synthetic anthocyanins (pigments) are studied for their ability to form inclusion complexes with cyclodextrins. As demonstrated from thermodn. and kinetic investigations, the effect of inclusion on color (fading) is opposed to that of typical mol. interactions involving anthocyanins (copigmentation).

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317

Nepogodiev, S. A. ; Stoddart, J. F. Cyclodextrin-Based Catenanes and Rotaxanes. Chem. Rev. 1998, 98 , 1959– 1976, DOI: 10.1021/cr970049w

[ACS Full Text ], [CAS], Google Scholar

317

Cyclodextrin-Based Catenanes and Rotaxanes

Nepogodiev, Sergey A.; Stoddart, J. Fraser

Chemical Reviews (Washington, D. C.) (1998), 98 (5), 1959-1976CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review with 91 refs. on the self-assembly and inclusion reaction of cyclodextrin-based catenanes and rotaxanes with polymers.

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318

Kaifer, A. E. Interplay between Molecular Recognition and Redox Chemistry. Acc. Chem. Res. 1999, 32 , 62– 71, DOI: 10.1021/ar970335u

[ACS Full Text ], [CAS], Google Scholar

318

Interplay between molecular recognition and redox chemistry

Kaifer, Angel E.

Accounts of Chemical Research (1999), 32 (1), 62-71CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review with 44 refs. is given. A summary of recent work on redox control of host-guest interactions, with emphasis on work performed by my own group. First, I will start with a description of the work in homogeneous soln. with three important classes of hosts, namely, cyclodextrins, calixarenes, and cyclophanes. Next, I will briefly discuss the application of host-guest chem. at the electrode-soln. interface. The last part of the Account will be devoted to a survey of recent results with encapsulated redox centers and dendrimer systems.

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319

Harada, A. ; Takashima, Y. ; Yamaguchi, H. Cyclodextrin-Based Supramolecular Polymers. Chem. Soc. Rev. 2009, 38 , 875– 882, DOI: 10.1039/b705458k

[Crossref], [PubMed], [CAS], Google Scholar

319

Cyclodextrin-based supramolecular polymers

Harada, Akira; Takashima, Yoshinori; Yamaguchi, Hiroyasu

Chemical Society Reviews (2009), 38 (4), 875-882CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review with refs. This tutorial review overviews construction of some inclusion supramol. architectures formed by cyclodextrins or their derivs. with guest mols. In the first part, the construction of supramol. structures of cyclodextrins with some polymers (polyrotaxanes) is described. In the second part, formation of supramol. oligomers and polymers formed by cyclodextrin derivs. is described.

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320

Harada, A. ; Hashidzume, A. ; Yamaguchi, H. ; Takashima, Y. Polymeric Rotaxanes. Chem. Rev. 2009, 109 , 5974– 6023, DOI: 10.1021/cr9000622

[ACS Full Text ], [CAS], Google Scholar

320

CD-based polymeric rotaxanes

Harada, Akira; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Takashima, Yoshinori

Chemical Reviews (Washington, DC, United States) (2009), 109 (11), 5974-6023CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. This review covers mainly peer-reviewed papers on polymeric rotaxanes since 1990. Herein the sections are classified according to the polyrotaxane structure: main chain polyrotaxanes and side chain polyrotaxanes. In the next sections, various polyrotaxanes are discussed according to their structures and components. The review is focused mainly on CD-based systems. However, polymeric rotaxanes contg. other cyclic compds. are also introduced.

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321

Harada, A. Cyclodextrin-Based Molecular Machines. Acc. Chem. Res. 2001, 34 , 456– 464, DOI: 10.1021/ar000174l

[ACS Full Text ], [CAS], Google Scholar

321

Cyclodextrin-based molecular machines

Harada, Akira

Accounts of Chemical Research (2001), 34 (6), 456-464CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review with 37 refs. Cyclodextrins have been used as a cyclic component in the construction of supramol. architectures. Recently they have been studied as a component in the construction of rotaxanes and catenanes. A cyclodextrin ring can translocate in some rotaxane and catenane structures. Therefore, much attention has been given to cyclodextrins as a component of mol. shuttles, motors, and machines. Attempts to design and synthesize mol.-level machines using cyclodextrins as a cyclic component are described.

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322

Basilio, N. ; Fernandes, A. ; de Freitas, V. ; Gago, S. ; Pina, F. Effect of Beta-Cyclodextrin on the Chemistry of 3 ',4 ',7-Trihydroxyflavylium. New J. Chem. 2013, 37 , 3166– 3173, DOI: 10.1039/c3nj00588g

[Crossref], [CAS], Google Scholar

322

Effect of β-cyclodextrin on the chemistry of 3',4',7-trihydroxyflavylium

Basilio, Nuno; Fernandes, Ana; de Freitas, Victor; Gago, Sandra; Pina, Fernando

New Journal of Chemistry (2013), 37 (10), 3166-3173CODEN: NJCHE5; ISSN:1144-0546. (Royal Society of Chemistry)

The pH dependence of the network of chem. reactions involving 3',4',7-trihydroxyflavylium was studied and all the rate and equil. consts. were detd. in the presence and absence of β-cyclodextrin. The β-cyclodextrin increases the rate const. of the flavylium cation hydration to give the hemiketal and decreases the reverse rate const. (de-hydration). The quantum yield of the flavylium cation formation from irradn. of the trans-chalcone increases from 0.023 to 0.055, resp., in the absence and presence of β-cyclodextrin. NMR spectral characterization of the inclusion complex between 3',4',7-trihydroxyflavylium and β-cyclodextrin was performed by ROESY and suggests a structure in which the hydroxyl substituents at positions 3' and 4' interact with the internal surface of the β-cyclodextrin.

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323

Petrov, V. ; Stanimirov, S. ; Petrov, I. K. ; Fernandes, A. ; de Freitas, V. ; Pina, F. Emptying the Beta-Cyclodextrin Cavity by Light: Photochemical Removal of the Trans-Chalcone of 4 ',7-Dihydroxyflavylium. J. Phys. Chem. A 2013, 117 , 10692– 10701, DOI: 10.1021/jp4060582

[ACS Full Text ], [CAS], Google Scholar

323

Emptying the β-cyclodextrin cavity by light: Photochemical removal of the trans-chalcone of 4',7-dihydroxyflavylium

Petrov, Vesselin; Stanimirov, Stanislav; Petrov, Ivan K.; Fernandes, Ana; de Freitas, Victor; Pina, Fernando

Journal of Physical Chemistry A (2013), 117 (41), 10692-10701CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

The interaction between the network of chem. reactions of the compd. 4',7-dihydroxyflavylium and β-cyclodextrin was studied by means of pH jumps, followed by UV-vis absorption, flash photolysis, stopped flow, and NMR. The trans-chalcone is the network species exhibiting the strongest interaction with the host. In moderately acidic medium, 95% of the trans-chalcone, 2.5 × 10-5 M, in the presence of β-cyclodextrin, 9 × 10-3 M, is expected to fill the host cavity (assocn. const. 2.2 × 103 M-1). In contrast, flavylium cation does not interact (assocn. const. ≈ 0). Irradn. of the trans-chalcone in the presence of β-cyclodextrin 9 mM leads to the flavylium cation appearance. Light is thus capable of removing the trans-chalcone from the β-cyclodextrin, leaving the cavity empty. The system is reversible and trans-chalcone goes back to the initial state upon switching off the light due to the thermodn. favorable conversion of flavylium cation to trans-chalcone in the presence of β-cyclodextrin.

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Gago, S. ; Basilio, N. ; Fernandes, A. ; Freitas, V. ; Quintas, A. ; Pina, F. Photochromism of the Complex between 4'-(2-Hydroxyethoxy)-7-Hydroxyflavylium and Beta-Cyclodextrin, Studied by H-1 Nmr, Uv-Vis, Continuous Irradiation and Circular Dichroism. Dyes Pigm. 2014, 110 , 106– 112, DOI: 10.1016/j.dyepig.2014.04.038

[Crossref], [CAS], Google Scholar

324

Photochromism of the complex between 4'-(2-hydroxyethoxy)-7-hydroxyflavylium and β-cyclodextrin, studied by 1H NMR, UV-Vis, continuous irradiation and circular dichroism

Gago, Sandra; Basilio, Nuno; Fernandes, Ana; Freitas, Victor; Quintas, Alexandre; Pina, Fernando

Dyes and Pigments (2014), 110 (), 106-112CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The network of chem. reactions of the compd. 4'-(2-hydroxyethoxy)-7-hydroxyflavylium and its photochromic properties were studied in the absence and presence of β-cyclodextrin. The system was characterized by 1H NMR, UV-visible, continuous irradn. and CD. In the presence of β-cyclodextrin 4.8 mM the pK'a is reduced to 2.2. The assocn. consts. with β-cyclodextrin, follow the order trans-chalcone > quinoidal base > flavylium cation, resp. 1.7 × 103 M-1; 5.6 × 102 M-1; ≈0. The rate of inter-conversion of the network species increases in the presence of β-cyclodextrin circa 2.6 times. The appearance of an induced CD signal of trans-chalcone inside the β-cyclodextrin is described for the first time. It gives information about the position of the guest inside the host and allows the calcn. of the resp. assocn. const.

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Lopes-Costa, T. ; Basilio, N. ; Pedrosa, J. M. ; Pina, F. Photochromism of the Natural Dye 7,4 '-Dihydroxy-5-Methoxyflavylium (Dracoflavylium) in the Presence of (2-Hydroxypropyl)-Beta-Cyclodextrin. Photochem. Photobiol. Sci. 2014, 13 , 1420– 1426, DOI: 10.1039/C4PP00190G

[Crossref], [PubMed], [CAS], Google Scholar

325

Photochromism of the natural dye 7,4'-dihydroxy-5-methoxyflavylium (dracoflavylium) in the presence of (2-hydroxypropyl)-β-cyclodextrin

Lopes-Costa, Tania; Basilio, Nuno; Pedrosa, Jose M.; Pina, Fernando

Photochemical & Photobiological Sciences (2014), 13 (10), 1420-1426CODEN: PPSHCB; ISSN:1474-905X. (Royal Society of Chemistry)

A photochromic system based on dracoflavylium, a natural pigment extd. from Dragon's blood, a resin appearing in the injury parts of the tree Dracaena draco, is studied in water. The photochromism arises from the irradn. of the trans-chalcone, giving a mixt. of flavylium cation/quinoidal base as a photoproduct via cis-chalcone and hemiketal. The performance of the photochromic system can be improved in the presence of (2-hydroxypropyl)-β-cyclodextrin. A math. model to account for the details of the kinetics and thermodn. of the system was deduced. The model is general for all the host-guest systems involving the flavylium network of chem. reactions with 1 : 1 stoichiometric assocn.

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Petrov, V. ; Slavcheva, S. ; Stanimirov, S. ; Pina, F. Origin of the Metastable Stability in Flavylium Multistate Systems. J. Phys. Chem. A 2015, 119 , 2908– 2918, DOI: 10.1021/acs.jpca.5b01473

[ACS Full Text ], [CAS], Google Scholar

326

Origin of the Metastable Stability in Flavylium Multistate Systems

Petrov, Vesselin; Slavcheva, Stoyanka; Stanimirov, Stanislav; Pina, Fernando

Journal of Physical Chemistry A (2015), 119 (12), 2908-2918CODEN: JPCAFH; ISSN:1089-5639. (American Chemical Society)

Metastable states regarding the network of chem. reactions involving flavylium compds. were studied as well as the role they may play in models for optical memories capable of write-read-erase. A necessary requirement to achieve metastable states in flavylium systems is the existence of a high cis-trans isomerization barrier, as in 4'-hydroxyflavylium described through this paper. In an optical memory, the metastable state could be the signal to be detected upon the write step. In that case the autoerase is prevented by the metastable state. Conversely, the metastable state may be the initial state and prevents the auto and unwanted write step. The compd. 4'-hydroxyflavylium offers the possibility of achieving both of these two situations, depending on the sequence of the pH stimuli prior to light absorption. The pH dependent distribution of the flavylium species of the network in the presence of β-cyclodextrin was calcd. Improvement of the performance of the photochromic system in the presence of β-cyclodextrin was obsd.

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327

Gago, S. ; Basilio, N. ; Quintas, A. ; Pina, F. Effect of Beta-Cyclodextrin on the Multistate Species Distribution of 3-Methoxy-4',7-Dihydroxyflavylium. Discrimination of the Two Hemiketal Enantiomers. J. Agric. Food Chem. 2017, 65 , 6346– 6358, DOI: 10.1021/acs.jafc.6b04892

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327

Effect of β-Cyclodextrin on the Multistate Species Distribution of 3-Methoxy-4',7-dihydroxyflavylium. Discrimination of the Two Hemiketal Enantiomers

Gago, Sandra; Basilio, Nuno; Quintas, Alexandre; Pina, Fernando

Journal of Agricultural and Food Chemistry (2017), 65 (31), 6346-6358CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The effect of β-cyclodextrin on the mole fraction distribution of the multistate species of the anthocyanin model compd., 3-methoxy-4',7-dihydroxyflavylium, was studied by NMR, stopped flow, CD, and UV-visible absorption spectroscopy. The formation of inclusion complexes with hemiketal and trans-chalcone, possessing transition dipole moments in a parallel orientation to the cyclodextrin n-fold axis, was unequivocally proved by means of the pos.-induced CD signal. The discrimination of the two hemiketal enantiomers was achieved by the splitting of 1H NMR peaks in the presence β-cyclodextrin. The spectroscopic data shows that the β-cyclodextrin has only moderate enantioselectivity, slightly favoring one of the optical isomers. The obsd. binding affinity of β-cyclodextrin for the 3-methoxy-4',7-dihydroxyflavylium multistate species increases in the order flavylium cation < quinoidal base < hemiketal < trans-chalcone < cis-chalcone. As a result of this selectivity and the dynamic nature of the network, the equil. is displaced toward the formation of the chalcone species.

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328

Mendoza, J. ; Basilio, N. ; Dangles, O. ; Mora, N. ; Al Bittar, S. ; Pina, F. Binding of the Five Multistate Species of the Anthocyanin Analog 7-Beta-D-Glucopyranosyloxy-4'-Hydroxyflavylium to the Beta-Cyclodextrin Derivative Captisol. Dyes Pigm. 2017, 143 , 479– 487, DOI: 10.1016/j.dyepig.2017.04.061

[Crossref], [CAS], Google Scholar

328

Binding of the five multistate species of the anthocyanin analog 7-β-D-glucopyranosyloxy-4'-hydroxyflavylium to the β-cyclodextrin derivative captisol

Mendoza, Johan; Basilio, Nuno; Dangles, Olivier; Mora, Nathalie; Al Bittar, Sheiraz; Pina, Fernando

Dyes and Pigments (2017), 143 (), 479-487CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The host-guest chem. of the anthocyanin analog 7-β-D-glucopyranosyloxy-4'-hydroxyflavylium (GHF) was studied in the presence of the β-cyclodextrin deriv. captisol by stopped flow, UV-visible spectroscopy, flash photolysis, CD and isothermal titrn. calorimetry. The equil. and rate consts. of the multistate of chem. species derived from the flavylium ion were calcd. and compared with those in the absence of the host. A new procedure to obtain the host-guest assocn. consts. of the multistate (including the transient species) by superimposing the two energy level diagrams, in the presence and absence of the cyclodextrin, was developed. The results indicate that the magnitude of the assocn. consts. follows the order, trans-chalcone ≈ cis-chalcone ≈ hemiketal > quinoidal base > flavylium cation. The hydration equil. const. increases ca. 42 times in the presence of captisol as the hydration and dehydration rate consts. resp. increases and decreases. The other equil. consts. are modestly affected: the rate consts. of ring closure and opening are significantly decreased in the complex and the isomerization rate consts. increase in both directions. The quantum yield of the photochromic system in the presence of captisol is 0.3, i.e. 3 times higher than in the absence of the host.

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Basilio, N. ; Pina, F. Flavylium Network of Chemical Reactions in Confined Media: Modulation of 3 ',4 ',7-Trihydroxyflavilium Reactions by Host-Guest Interactions with Cucurbit[7]Uril. ChemPhysChem 2014, 15 , 2295– 2302, DOI: 10.1002/cphc.201402051

[Crossref], [PubMed], [CAS], Google Scholar

329

Flavylium Network of Chemical Reactions in Confined Media: Modulation of 3',4',7-Trihydroxyflavilium Reactions by Host-Guest Interactions with Cucurbit[7]uril

Basilio, Nuno; Pina, Fernando

ChemPhysChem (2014), 15 (11), 2295-2302CODEN: CPCHFT; ISSN:1439-4235. (Wiley-VCH Verlag GmbH & Co. KGaA)

In moderately acidic aq. solns., flavylium compds. undergo a pH-, and in some cases, light-dependent array of reversible chem. reactions. This network can be described as a single acid-base reaction involving a flavylium cation (acidic form) and a mixt. of basic forms (quinoidal base, hemiketal and cis and trans chalcones). The apparent pK'a of the system and the relative mole fractions of the basic forms can be modulated by the interaction with cucurbit[7]uril. The system is studied by using 1H NMR spectroscopy, UV/Vis spectroscopy, flash photolysis, and steady-state irradn. Of all the network species, the flavylium cation possesses the highest affinity for cucurbit[7]uril. The rate of interconversion between flavylium cation and the basic species (where trans-chalcone is dominant) is approx. nine times lower inside the cucurbit[7]uril.

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Basilio, N. ; Cabrita, L. ; Pina, F. Mimicking Positive and Negative Copigmentation Effects in Anthocyanin Analogues by Host-Guest Interaction with Cucurbit[7]Uril and Beta-Cyclodextrins. J. Agric. Food Chem. 2015, 63 , 7624– 7629, DOI: 10.1021/acs.jafc.5b00765

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330

Mimicking Positive and Negative Copigmentation Effects in Anthocyanin Analogues by Host-Guest Interaction with Cucurbit[7]uril and β-Cyclodextrins

Basilio, Nuno; Cabrita, Luis; Pina, Fernando

Journal of Agricultural and Food Chemistry (2015), 63 (35), 7624-7629CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Copigmentation and the anti-copigmentation effects can be mimicked by the interaction of anthocyanin's model compds. resp. with cucurbit[7]uril (CB7) and β-cyclodextrin (β-CD). The complex network of chem. reactions displayed by this family of compds. includes the colored flavylium cation, AH+, and quinoidal base, A, along with the colorless hemiketal, B, cis-chalcone, Cc, and trans-chalcone, Ct. Whereas AH+ is stable only at very acidic pH values, the remaining species are formed at slightly acidic and neutral conditions. However, under these conditions, for most of the natural and synthetic flavylium salts, the colorless species predominate (B, Cc, and Ct) at the expense of A. The host CB7 was found to improve the color of solns. in two different ways: first, it stabilizes AH+ at higher pH values by decreasing its acidity and, second, it enhances the mole fraction of A due to selective complexation of this species in the pH range where the flavylium cation is no longer stable. In contrast, β-CD increases the acidity of AH+, favoring the formation of Ct at the expense of all the other multistate species. Although both hosts have a large effect on the hydration rate and pH domain of the flavylium cation, the effect on the degrdn. kinetics of anthocyanidins is modest. CB7 decreases the hydration rate and decreases the acid-base (AH+/A) equil. const. (Ka), leading resp. to a slowing and a speeding of the anthocyanin degrdn. rate. On the other hand, β-CD increases the hydration rate but increases Ka, both effects acting in opposite directions.

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Basilio, N. ; Petrov, V. ; Pina, F. Host-Guest Complexes of Flavylium Cations and Cucurbit[7]Uril: The Influence of Flavylium Substituents on the Structure and Stability of the Complex. ChemPlusChem 2015, 80 , 1779– 1785, DOI: 10.1002/cplu.201500304

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331

Host-Guest Complexes of Flavylium Cations and Cucurbit[7]uril: The Influence of Flavylium Substituents on the Structure and Stability of the Complex

Basilio, Nuno; Petrov, Vesselin; Pina, Fernando

ChemPlusChem (2015), 80 (12), 1779-1785CODEN: CHEMM5; ISSN:2192-6506. (Wiley-VCH Verlag GmbH & Co. KGaA)

The host-guest complexes formed from six differently substituted flavylium cations and cucurbit[7]uril (CB7) have been characterized by UV/Vis absorption, fluorescence emission and 1H NMR spectroscopy. It was obsd. that all flavylium cations form 1:1 inclusion complexes with assocn. consts. that depend on the nature and position of the substituents. The results indicate that CB7 displays higher affinity for more hydrophobic flavylium compds. and for those bearing amino substituents. 1H NMR spectroscopy was used to elucidate the structure of the complexes. While for 7-hydroxyflavylium and 4-methyl-7-hydroxyflavylium the Ph group (ring B) is included within the host's cavity leaving the benzopyrilium group (rings A and C) outside, in 4',7-dihydroxyflavylium and 3',4',7-trihydroxyflavylium the macrocycle shuttles between rings A and B. For compds. with amino substituents it was found that CB7 is attracted towards these groups regardless of their position in ring A or B. In addn., it was obsd. that the dimethylamino group tends to be positioned near the carbonyl-decorated portal while the diethylamino motif prefers the hydrophobic cavity of CB7.

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Diniz, A. M. ; Basilio, N. ; Cruz, H. ; Pina, F. ; Parola, A. J. Spatiotemporal Control over the Co-Conformational Switching in Ph-Responsive Flavylium-Based Multistate Pseudorotaxanes. Faraday Discuss. 2015, 185 , 361– 379, DOI: 10.1039/C5FD00078E

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332

Spatiotemporal control over the co-conformational switching in pH-responsive flavylium-based multistate pseudorotaxanes

Diniz, Ana Marta; Basilio, Nuno; Cruz, Hugo; Pina, Fernando; Parola, A. Jorge

Faraday Discussions (2015), 185 (), 361-379CODEN: FDISE6; ISSN:1359-6640. (Royal Society of Chemistry)

A multistate mol. dyad contg. flavylium and viologen units was synthesized and the pH dependent thermodn. of the network completely characterized by a variety of spectroscopic techniques such as NMR, UV-vis and stopped-flow. The flavylium cation is only stable at acidic pH values. Above pH ≈ 5 the hydration of the flavylium leads to the formation of the hemiketal followed by ring-opening tautomerization to give the cis-chalcone. Finally, this last species isomerizes to give the trans-chalcone. For the present system only the flavylium cation and the trans-chalcone species could be detected as being thermodynamically stable. The hemiketal and the cis-chalcone are kinetic intermediates with negligible concns. at the equil. All stable species of the network were found to form 1:1 and 2:1 host:guest complexes with cucurbit[7]uril (CB7) with assocn. consts. in the ranges 105-108 M-1 and 103-104 M-1, resp. The 1:1 complexes were particularly interesting to devise pH responsive bistable pseudorotaxanes: at basic pH values (≈12) the flavylium cation interconverts into the deprotonated trans-chalcone in a few minutes and under these conditions the CB7 wheel was found to be located around the viologen unit. A decrease in pH to values around 1 regenerates the flavylium cation in seconds and the macrocycle is translocated to the middle of the axle. On the other hand, if the pH is decreased to 6, the deprotonated trans-chalcone is neutralized to give a metastable species that evolves to the thermodynamically stable flavylium cation in ca. 20 h. By taking advantage of the pH-dependent kinetics of the trans-chalcone/flavylium interconversion, spatiotemporal control of the mol. organization in pseudorotaxane systems can be achieved.

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Basilio, N. ; Cruz, L. ; de Freitas, V. ; Pina, F. A Multistate Molecular Switch Based on the 6,8-Rearrangement in Bromo-Apigeninidin Operated with Ph and Host- Guest Inputs. J. Phys. Chem. B 2016, 120 , 7053– 7061, DOI: 10.1021/acs.jpcb.6b03694

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333

A Multistate Molecular Switch Based on the 6,8-Rearrangement in Bromo-apigeninidin Operated with pH and Host-Guest Inputs

Basilio, Nuno; Cruz, Luis; de Freitas, Victor; Pina, Fernando

Journal of Physical Chemistry B (2016), 120 (29), 7053-7061CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

The equil. between 6- and 8-bromo-apigeninidin is quant. displaced toward the formation of the former in the presence of cucurbit[7]uril because of the selective recognition of the 6-bromo isomer by the host. This phenomenon permits us to conceive a unidirectional multistate switch addressed with host-guest inputs and enables the reversible activation and deactivation of the 6-/8-bromo-apigeninidin dynamic mol. multistate through coupled host-guest and pH inputs.

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Basilio, N. ; Pischel, U. Drug Delivery by Controlling a Supramolecular Host-Guest Assembly with a Reversible Photoswitch. Chem. - Eur. J. 2016, 22 , 15208– 15211, DOI: 10.1002/chem.201603331

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334

Drug delivery by controlling a supramolecular host-guest assembly with a reversible photoswitch

Basilio, Nuno; Pischel, Uwe

Chemistry - A European Journal (2016), 22 (43), 15208-15211CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

The reversibly switchable trans-chalcone/flavylium photochromic system was successfully coupled to the complexation equil. of a drug-cucurbit[7]uril host-guest assembly. Hence, the phototriggered release of memantine under illumination at 366 nm was obsd. The process can be partially reverted through a thermally activated back reaction.

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Seco, A. ; Diniz, A. M. ; Sarrato, J. ; Mourao, H. ; Cruz, H. ; Parola, A. J. ; Basilio, N. A Pseudorotaxane Formed from a Cucurbit[7] Uril Wheel and a Bioinspired Molecular Axle with Ph, Light and Redox-Responsive Properties. Pure Appl. Chem. 2020, 92 , 301– 313, DOI: 10.1515/pac-2019-0225

[Crossref], [CAS], Google Scholar

335

A pseudorotaxane formed from a cucurbit[7]uril wheel and a bioinspired molecular axle with pH, light and redox-responsive properties

Seco, Andre; Diniz, Ana Marta; Sarrato, Joao; Mourao, Henrique; Cruz, Hugo; Parola, A. Jorge; Basilio, Nuno

Pure and Applied Chemistry (2020), 92 (2), 301-313CODEN: PACHAS; ISSN:0033-4545. (Walter de Gruyter, Inc.)

A pH-, light- and redox-responsive flavylium-bipyridinium mol. dyad (bioinspired in natural anthocyanins) was synthesized and employed to devise a pseudorotaxane with the macrocycle cucurbit[7]uril (CB7) in aq. soln. The inclusion complex was characterized by UV-Vis absorption, fluorescence emission, NMR and electrochem. techniques which demonstrate formation of a stable binary complex between the dyad and CB7 both under acidic and neutral conditions. It is noteworthy that the flavylium-bipyridinium tricationic dyad is only stable in highly acidic media, undergoing a reversible hydration reaction at slightly acidic or neutral pH to give a trans-chalcone-bipyridinium dication. The 1H NMR expts. showed that in this last species the CB7 binds to the bipyridinium unit while in the tricationic species the macrocycle is positioned between the flavylium and the bipyridinium moieties. The different location of the CB7 wheel in the two dyad states allows control of the shuttling movement using light and pH stimuli that trigger the interconversion between these two species.

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336

Romero, M. A. ; Fernandes, R. J. ; Moro, A. J. ; Basilio, N. ; Pischel, U. Light-Induced Cargo Release from a Cucurbit[8]Uril Host by Means of a Sequential Logic Operation. Chem. Commun. 2018, 54 , 13335, DOI: 10.1039/C8CC07404F

[Crossref], [PubMed], [CAS], Google Scholar

336

Light-induced cargo release from a cucurbit[8]uril host by means of a sequential logic operation

Romero, Miguel A.; Fernandes, Rita J.; Moro, Artur J.; Basilio, Nuno; Pischel, Uwe

Chemical Communications (Cambridge, United Kingdom) (2018), 54 (95), 13335-13338CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

The logically controlled and light-induced release of a tripeptide model cargo from a cucurbit[8]uril host macrocycle by means of a photoswitch was shown in water. This provides a new approach to photoresponsive and selective release in a meaningful pH window.

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Held, B. ; Tang, H. ; Natarajan, P. ; da Silva, C. P. ; Silva, V. D. ; Bohne, C. ; Quina, F. H. Cucurbit[7]Uril Inclusion Complexation as a Supramolecular Strategy for Color Stabilization of Anthocyanin Model Compounds. Photochem. Photobiol. Sci. 2016, 15 , 752– 757, DOI: 10.1039/C6PP00060F

[Crossref], [PubMed], [CAS], Google Scholar

337

Cucurbit[7]uril inclusion complexation as a supramolecular strategy for color stabilization of anthocyanin model compounds

Held, Barbara; Tang, Hao; Natarajan, Palani; Pacheco da Silva, Cassio; Silva, Volnir de Oliveira; Bohne, Cornelia; Quina, Frank H.

Photochemical & Photobiological Sciences (2016), 15 (6), 752-757CODEN: PPSHCB; ISSN:1474-905X. (Royal Society of Chemistry)

Host-guest complexation with cucurbit[7]uril of anthocyanin model compds. in which acid-base equil. are blocked resulted in essentially complete stabilization of their color. The color protection is a thermodn. effect and establishes a strategy to stabilize these colored compds. at pH values of interest for practical applications.

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338

Zubillaga, A. ; Ferreira, P. ; Parola, A. J. ; Gago, S. ; Basilio, N. Ph-Gated Photoresponsive Shuttling in a Water-Soluble Pseudorotaxane. Chem. Commun. 2018, 54 , 2743– 2746, DOI: 10.1039/C8CC00688A

[Crossref], [PubMed], [CAS], Google Scholar

338

pH-Gated photoresponsive shuttling in a water-soluble pseudorotaxane

Zubillaga, A.; Ferreira, P.; Parola, A. J.; Gago, S.; Basilio, N.

Chemical Communications (Cambridge, United Kingdom) (2018), 54 (22), 2743-2746CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

A fluorescent bistable pseudorotaxane was devised and shown to display pH-gated photoresponsive ring shuttling. At pH > 7.5 shuttling does not take place after light stimulation while at pH ≈ 5 the macrocycle is quant. translocated.

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339

Basilio, N. ; Laia, C. A. T. ; Pina, F. Excited-State Proton Transfer in Confined Medium. 4-Methy1–7-Hydroxyflavylium and Beta-Naphthol Incorporated in Cucurbit[7]Uril. J. Phys. Chem. B 2015, 119 , 2749– 2757, DOI: 10.1021/jp511351w

[ACS Full Text ], [CAS], Google Scholar

339

Excited-State Proton Transfer in Confined Medium. 4-Methyl-7-hydroxyflavylium and β-Naphthol Incorporated in Cucurbit[7]uril

Basilio, Nuno; Laia, Cesar A. T.; Pina, Fernando

Journal of Physical Chemistry B (2015), 119 (6), 2749-2757CODEN: JPCBFK; ISSN:1520-5207. (American Chemical Society)

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Lagona, J. ; Mukhopadhyay, P. ; Chakrabarti, S. ; Isaacs, L. The Cucurbit[N]Uril Family. Angew. Chem., Int. Ed. 2005, 44 , 4844– 4870, DOI: 10.1002/anie.200460675

[Crossref], [CAS], Google Scholar

340

The cucurbit[n]uril family

Lagona, Jason; Mukhopadhyay, Pritam; Chakrabarti, Sriparna; Isaacs, Lyle

Angewandte Chemie, International Edition (2005), 44 (31), 4844-4870CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

A review. In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed cucurbituril by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants-the pumpkin. In the intervening years, the fundamental binding properties of CB[6]-high affinity, highly selective, and constrictive binding interactions-were delineated by the pioneering work of the research groups of Mock, Kim, and Buschmann, and led to their applications in wastewater remediation, as artificial enzymes, and as mol. switches. More recently, the cucurbit[n]uril family has grown to include homologs (CB[5]-CB[10]), derivs., congeners, and analogs whose sizes span and exceed the range available with the α-, β-, and γ-cyclodextrins. Their shapes, soly., and chem. functionality may now be tailored by synthetic chem. to play a central role in mol. recognition, self-assembly, and nano-technol. This Review focuses on the synthesis, recognition properties, and applications of these unique macrocycles.

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Kim, K. ; Selvapalam, N. ; Ko, Y. H. ; Park, K. M. ; Kim, D. ; Kim, J. Functionalized Cucurbiturils and Their Applications. Chem. Soc. Rev. 2007, 36 , 267– 279, DOI: 10.1039/B603088M

[Crossref], [PubMed], [CAS], Google Scholar

341

Functionalized cucurbiturils and their applications

Kim, Kimoon; Selvapalam, Narayanan; Ko, Young Ho; Park, Kyeng Min; Kim, Dongwoo; Kim, Jeeyeon

Chemical Society Reviews (2007), 36 (2), 267-279CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Cucurbit[n]uril (CB[n], n = 5-10), a new family of mol. hosts comprising n glycoluril units, have gained much attention in the new millennium for their exceptional mol. recognition ability. The CB homologues have brought dynamism to CB chem., as witnessed by the heightened interest in the field for the last several years. Compared to the chem. of cyclodextrins and calixarenes, however, that of CB[n] has developed slowly until recently, which may be attributed mainly to their poor soly. in common solvents, and inability to functionalize these mols. The direct functionalization method of CB[n] propelled CB chem. to a new height as this new method not only solved the soly. problem but also opened up the gateway to the generation of tailor-made CB[n] derivs. The functionalization of CB[n] led us to investigate numerous applications including artificial ion channels, vesicles, stationary phases in chromatog., ISEs, polymers, nanomaterials, and many others. This tutorial review describes the recent advances and challenges in the functionalization of CBs along with the applications of functionalized CBs.

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Barrow, S. J. ; Kasera, S. ; Rowland, M. J. ; del Barrio, J. ; Scherman, O. A. Cucurbituril-Based Molecular Recognition. Chem. Rev. 2015, 115 , 12320– 12406, DOI: 10.1021/acs.chemrev.5b00341

[ACS Full Text ], [CAS], Google Scholar

342

Cucurbituril-based molecular recognition

Barrow, Steven J.; Kasera, Setu; Rowland, Matthew J.; del Barrio, Jesus; Scherman, Oren A.

Chemical Reviews (Washington, DC, United States) (2015), 115 (22), 12320-12406CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. In this review, we cover the vast areas of scientific research upon which CB[n]s have impacted, with a focus on the guest recognition properties of CB[n], largely but not wholly concerning of their utilization in soln. phase where most applications have arisen. To understand the binding properties of CB[n], a general overview of the thermodn. of CB[n] binding is first discussed, followed by an individual anal. of the specific binding properties of CB[5]-CB[8]. Looking toward the application of CB[n] complexation, the areas of gas encapsulation, CB[n]s on surfaces, CB[n]-mediated supramol. polymers, mol. recognition in 3D supramol. networks, CB[n] catalysis and reaction templating, nd CB[n] recognition in biol. systems will each be discussed in turn. Addnl., this review provides the reader with a comprehensive guide to the guest mols. that have been studied with CB[5,6,7,8].

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Assaf, K. I. ; Nau, W. M. Cucurbiturils: From Synthesis to High-Affinity Binding and Catalysis. Chem. Soc. Rev. 2015, 44 , 394– 418, DOI: 10.1039/C4CS00273C

[Crossref], [PubMed], [CAS], Google Scholar

343

Cucurbiturils: from synthesis to high-affinity binding and catalysis

Assaf, Khaleel I.; Nau, Werner M.

Chemical Society Reviews (2015), 44 (2), 394-418CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. In the wide area of supramol. chem., cucurbit[n]urils (CBn) present themselves as a young family of mol. containers, able to form stable complexes with various guests, including drug mols., amino acids and peptides, saccharides, dyes, hydrocarbons, perfluorinated hydrocarbons, and even high mol. wt. guests such as proteins (e.g., human insulin). Since the discovery of the first CBn, CB6, the field has seen tremendous growth with respect to the synthesis of new homologues and derivs., the discovery of record binding affinities of guest mols. in their hydrophobic cavity, and assocd. applications ranging from sensing to drug delivery. In this review, we discuss in detail the fundamental properties of CBn homologs and their cyclic derivs. with a focus on their synthesis and their applications in catalysis.

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Cao, L. P. ; Sekutor, M. ; Zavalij, P. Y. ; Mlinaric-Majerski, K. ; Glaser, R. ; Isaacs, L. Cucurbit[7]Uril.Guest Pair with an Attomolar Dissociation Constant. Angew. Chem., Int. Ed. 2014, 53 , 988– 993, DOI: 10.1002/anie.201309635

[Crossref], [CAS], Google Scholar

344

Cucurbit[7]uril.Guest Pair with an Attomolar Dissociation Constant

Cao, Liping; Sekutor, Marina; Zavalij, Peter Y.; Mlinaric-Majerski, Kata; Glaser, Robert; Isaacs, Lyle

Angewandte Chemie, International Edition (2014), 53 (4), 988-993CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

Host·guest complexes between cucurbit[7]uril (CB[7]) or CB[8] and diamantane diammonium ion guests I and II were studied by 1H NMR spectroscopy and x-ray crystallog. 1H NMR competition expts. revealed that CB[7]·II is among the tightest monovalent noncovalent complexes ever reported in water with Ka = 7.2 × 1017 M-1 in pure D2O and 1.9 × 1015 M-1 in D2O buffered with NaO2CCD3 (50 mM). The crystal structure of CB[7]·II allowed us to identify some of the structural features responsible for the ultratight binding, including the distance between the NMe3+ groups of II (7.78 Å), which allows it to establish 14 optimal ion-dipole interactions with CB[7], the complementarity of the convex van der Waals surface contours of II with the corresponding concave surfaces of CB[7], desolvation of the C=O portals within the CB[7]·II complex, and the co-linearity of the C7 axis of CB[7] with the N+···N+ line in II. This work further blurs the lines of distinction between natural and synthetic receptors.

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Ghosh, I. ; Nau, W. M. The Strategic Use of Supramolecular Pk(a) Shifts to Enhance the Bioavailability of Drugs. Adv. Drug Delivery Rev. 2012, 64 , 764– 783, DOI: 10.1016/j.addr.2012.01.015

[Crossref], [PubMed], [CAS], Google Scholar

345

The strategic use of supramolecular pKa shifts to enhance the bioavailability of drugs

Ghosh, Indrajit; Nau, Werner M.

Advanced Drug Delivery Reviews (2012), 64 (9), 764-783CODEN: ADDREP; ISSN:0169-409X. (Elsevier B.V.)

A review. Macrocyclic hosts of the cyclodextrin, sulfonatocalixarene, and cucurbituril type can be employed as discrete supramol. drug delivery systems, thereby complementing existing supramol. drug formulation strategies based on polymers, hydrogels, liposomes, and related microheterogeneous systems. Cucurbiturils, in particular, stand out in that they do not only provide a hydrophobic cavity to encapsulate the drug in the form of a host-guest complex, but in that they possess cation-receptor properties, which favor the encapsulation of protonated drugs over their unprotonated forms, resulting in pronounced pKa shifts up to 5 units. These pKa shifts can be rationally exploited to activate prodrug mols., to stabilize the active form of drug mols., to enhance their soly., and to increase their degree of ionization, factors which can jointly serve to enhance the bioavailability of drugs, particularly weakly basic ones. Addnl., macrocycles can serve to increase the chem. stability of drugs by protecting them against reactions with nucleophiles (e.g., thiols) and electrophiles, by increasing their photostability, and by causing a higher thermal stability in the solid state. Detailed examples of the different effects of macrocyclic encapsulation of drugs and the assocd. pKa shifts are provided and discussed. Other important considerations, namely a potential lowering of the bioactivity of drugs by macrocyclic complexation, interferences of the macrocycles with biocatalytic processes, the toxicity of the macrocyclic host mols., and problems and opportunities related to a targeted release and the rate of release of the drug from the host-guest complexes are critically evaluated.

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Biedermann, F. ; Uzunova, V. D. ; Scherman, O. A. ; Nau, W. M. ; De Simone, A. Release of High-Energy Water as an Essential Driving Force for the High-Affinity Binding of Cucurbit[N]Urils. J. Am. Chem. Soc. 2012, 134 , 15318– 15323, DOI: 10.1021/ja303309e

[ACS Full Text ], [CAS], Google Scholar

346

Release of High-Energy Water as an Essential Driving Force for the High-Affinity Binding of Cucurbit[n]urils

Biedermann, Frank; Uzunova, Vanya D.; Scherman, Oren A.; Nau, Werner M.; De Simone, Alfonso

Journal of the American Chemical Society (2012), 134 (37), 15318-15323CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

Mol. dynamics simulations and isothermal titrn. calorimetry (ITC) expts. with neutral guests illustrate that the release of high-energy water from the cavity of cucurbit[n]uril (CBn) macrocycles is a major determinant for guest binding in aq. solns. The energy of the individual encapsulated water mols. decreases with increasing cavity size, because larger cavities allow for the formation of more stable H-bonded networks. Conversely, the total energy of internal water increases with the cavity size because the abs. no. of water mols. increases. For CB7, which has emerged as an ultrahigh affinity binder, these counteracting effects result in a max. energy gain through a complete removal of water mols. from the cavity. A new design criterion for aq. synthetic receptors has therefore emerged, which is the optimization of the size of cavities and binding pockets with respect to the energy and no. of residing water mols.

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Basilio, N. ; Mendoza, J. ; Gago, S. ; Parola, A. J. Ph-Driven Self-Sorting in a Four Component Host-Guest System. Chem. Commun. 2017, 53 , 6472– 6475, DOI: 10.1039/C7CC02432K

[Crossref], [PubMed], [CAS], Google Scholar

347

pH-Driven self-sorting in a four component host-guest system

Basilio, Nuno; Mendoza, Johan; Gago, Sandra; Parola, A. Jorge

Chemical Communications (Cambridge, United Kingdom) (2017), 53 (48), 6472-6475CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

A four component host-guest system comprising β-cyclodextrin (β-CD), cucurbit[7]uril (CB7) and two chalcone guests was demonstrated to undergo pH-triggered self-sorting in aq. soln. This phenomenon arises from the contrasting complexation induced pKa shifts displayed by these guests after complexation with CB7.

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Basilio, N. ; Gago, S. ; Parola, A. J. ; Pina, F. Contrasting Pk(a) Shifts in Cucurbit[7]Uril Host-Guest Complexes Governed by an Interplay of Hydrophobic Effects and Electrostatic Interactions. ACS Omega 2017, 2 , 70– 75, DOI: 10.1021/acsomega.6b00427

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348

Contrasting pKa Shifts in Cucurbit[7]uril Host-Guest Complexes Governed by an Interplay of Hydrophobic Effects and Electrostatic Interactions

Basilio, Nuno; Gago, Sandra; Parola, A. Jorge; Pina, Fernando

ACS Omega (2017), 2 (1), 70-75CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)

Cucurbit[7]uril inclusion complexes with guests bearing dimethylamino groups shows the expected upward pKa shifts while their diethylamino counterparts display a decrease in the pKa due to the preferential stabilization of the unprotonated form. These results reveal the diethylamino group as the substituent of choice to avoid receptor-assisted protonation of guest mols. and presents new evidence for the role of the hydrophobic effect as driving force in cucurbituril complexation.

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de Silva, A. P. ; McClenaghan, N. D. Molecular-Scale Logic Gates. Chem. - Eur. J. 2004, 10 , 574– 586, DOI: 10.1002/chem.200305054

[Crossref], [PubMed], [CAS], Google Scholar

349

Molecular-scale logic gates

de Silva A Prasanna; McClenaghan Nathan D

Chemistry (Weinheim an der Bergstrasse, Germany) (2004), 10 (3), 574-86 ISSN:0947-6539.

Currently available approaches to molecular-scale logic gates are summarized and compared. These include: chemically-controlled fluorescent and transmittance-based switches concerned with small molecules, DNA oligonucleotides with fluorescence readout, oligonucleotide reactions with DNA-based catalysts, chemically-gated photochromics, reversibly denaturable proteins, molecular machines with optical and electronic signals, two-photon fluorophores and multichromophoric transient optical switches. The photochemical principles of electron and energy transfer are involved in several of these approaches. More complex molecular logic systems with reconfigurability and superposability provide contrasts with current semiconductor electronics. Integration of simple logic functions to produce more complex ones is also discussed in terms of recent developments.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2c%252FmsFahuw%253D%253D&md5=04cbbd62439c9ae126777fbda15c77e1

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Andreasson, J. ; Pischel, U. Molecules with a Sense of Logic: A Progress Report. Chem. Soc. Rev. 2015, 44 , 1053– 1069, DOI: 10.1039/C4CS00342J

[Crossref], [PubMed], [CAS], Google Scholar

350

Molecules with a sense of logic: a progress report

Andreasson, Joakim; Pischel, Uwe

Chemical Society Reviews (2015), 44 (5), 1053-1069CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

In this tutorial review, the most recent developments in the field of mol. logic and information processing are discussed. Special emphasis is given to the report of progress in the concatenation of mol. logic devices and switches, the design of memory systems working according to the principles of sequential logic, the mimicking of transistors, and the research on photochromic platforms with an unprecedented degree of functional integration. Furthermore, a series of achievements that add up to the conceptual diversity of mol. logic is introduced, such as the realization of highly complex and logically reversible Toffoli and Fredkin gates by the action of DNAzymes or the use of a multifluorophoric platform as a viable approach towards keypad lock functions.

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351

de Silva, P. A. ; Gunaratne, N. H. Q. ; McCoy, C. P. A Molecular Photoionic and Gate Based on Fluorescent Signalling. Nature 1993, 364 , 42– 44, DOI: 10.1038/364042a0

352

Liu, Y. L. ; Yu, Y. ; Gao, J. A. ; Wang, Z. Q. ; Zhang, X. Water-Soluble Supramolecular Polymerization Driven by Multiple Host-Stabilized Charge-Transfer Interactions. Angew. Chem., Int. Ed. 2010, 49 , 6576– 6579, DOI: 10.1002/anie.201002415

[Crossref], [CAS], Google Scholar

352

Water-Soluble Supramolecular Polymerization Driven by Multiple Host-Stabilized Charge-Transfer Interactions

Liu, Yiliu; Yu, Ying; Gao, Jian; Wang, Zhiqiang; Zhang, Xi

Angewandte Chemie, International Edition (2010), 49 (37), 6576-6579, S6576/1-S6576/13CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

The author's prep. a novel water sol. supramol. polymer with high d.p. that is based on multiple HSCT (host-stabilized charge transfer) interactions. It was demonstrated that multiple HSCT interactions, which possess a high binding const. and orientation selectivity, can be used as the driving force to construct a supramol. polymer. This study enriches the field of supramol. polymn. with new building blocks and driving forces, and the concept is expected to be used as a new effective method for fabricating supramol. materials.

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Appel, E. A. ; del Barrio, J. ; Loh, X. J. ; Scherman, O. A. Supramolecular Polymeric Hydrogels. Chem. Soc. Rev. 2012, 41 , 6195– 6214, DOI: 10.1039/c2cs35264h

[Crossref], [PubMed], [CAS], Google Scholar

353

Supramolecular polymeric hydrogels

Appel, Eric A.; del Barrio, Jesus; Loh, Xian Jun; Scherman, Oren A.

Chemical Society Reviews (2012), 41 (18), 6195-6214CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. The supramol. crosslinking of polymer chains in water by specific, directional and dynamic non-covalent interactions has led to the development of novel supramol. polymeric hydrogels. These aq. polymeric networks constitute an interesting class of soft materials exhibiting attractive properties such as stimuli-responsiveness and self-healing arising from their dynamic behavior and that are crucial for a wide variety of emerging applications. We present here a crit. review summarizing the formation of dynamic polymeric networks through specific non-covalent interactions. Aq. supramol. chem. has unlocked a versatile toolbox for the design and fine-tuning of the material properties of these hydrogels.

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354

Yang, H. ; Yuan, B. ; Zhang, X. ; Scherman, O. A. Supramolecular Chemistry at Interfaces: Host-Guest Interactions for Fabricating Multifunctional Biointerfaces. Acc. Chem. Res. 2014, 47 , 2106– 2115, DOI: 10.1021/ar500105t

[ACS Full Text ], [CAS], Google Scholar

354

Supramolecular Chemistry at Interfaces: Host-Guest Interactions for Fabricating Multifunctional Biointerfaces

Yang, Hui; Yuan, Bin; Zhang, Xi; Scherman, Oren A.

Accounts of Chemical Research (2014), 47 (7), 2106-2115CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review. Host-guest chem. can greatly improve the selectivity of biomol.-ligand binding on account of recognition-directed interactions. In addn., functional structures and the actuation of supramol. assemblies in mol. systems can be controlled efficiently through various host-guest chem. Together, these highly selective, strong yet dynamic interactions can be exploited as an alternative methodol. for applications in the field of programmable and controllable engineering of supramol. soft materials through the reversible binding between complementary components. Many processes in living systems such as biotransformation, transportation of matter, and energy transduction begin with interfacial mol. recognition, which is greatly influenced by various external stimuli at biointerfaces. Detailed investigations about the mol. recognition at interfaces can result in a better understanding of life science, and further guide us in developing new biomaterials and medicines. In order to mimic complicated mol.-recognition systems obsd. in nature that adapt to changes in their environment, combining host-guest chem. and surface science is crit. for fabricating the next generation of multifunctional biointerfaces with efficient stimuli-responsiveness and good biocompatibility. In this Account, we will summarize some recent progress on multifunctional stimuli-responsive biointerfaces and biosurfaces fabricated by cyclodextrin- or cucurbituril-based host-guest chem. and highlight their potential applications including drug delivery, bioelectrocatalysis, and reversible adsorption and resistance of peptides, proteins, and cells. In addn., these biointerfaces and biosurfaces demonstrate efficient response toward various external stimuli, such as UV light, pH, redox chem., and competitive guests. All of these external stimuli can aid in mimicking the biol. stimuli evident in complex biol. environments. We begin by reviewing the current state of stimuli-responsive supramol. assemblies formed by host-guest interactions, discussing how to transfer host-guest chem. from soln. onto surfaces required for fabricating multifunctional biosurfaces and biointerfaces. Then, we present different stimuli-responsive biosurfaces and biointerfaces, which have been prepd. through a combination of cyclodextrin- or cucurbituril-based host-guest chem. and various surface technologies such as self-assembled monolayers or layer-by-layer assembly. Moreover, we discuss the applications of these biointerfaces and biosurfaces in the fields of drug release, reversible adsorption and release of some org. mols., peptides, proteins, and cells, and photoswitchable bioelectrocatalysis. In addn., we summarize the merits and current limitations of these methods for fabricating multifunctional stimuli-responsive biointerfaces in a dynamic noncovalent manner. Finally, we present possible strategies for future designs of stimuli-responsive multifunctional biointerfaces and biosurfaces by combining host-guest chem. with surface science, which will lead to further crit. development of supramol. chem. at interfaces.

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355

Zhang, J. ; Coulston, R. J. ; Jones, S. T. ; Geng, J. ; Scherman, O. A. ; Abell, C. One-Step Fabrication of Supramolecular Microcapsules from Microfluidic Droplets. Science 2012, 335 , 690– 694, DOI: 10.1126/science.1215416

[Crossref], [PubMed], [CAS], Google Scholar

355

One-step fabrication of supramolecular microcapsules from microfluidic droplets

Zhang, Jing; Coulston, Roger J.; Jones, Samuel T.; Geng, Jin; Scherman, Oren A.; Abell, Chris

Science (Washington, DC, United States) (2012), 335 (6069), 690-694CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)

Although many techniques exist for prepg. microcapsules, it is still challenging to fabricate them in an efficient and scalable process without compromising functionality and encapsulation efficiency. We demonstrated a simple one-step approach that exploits a versatile host-guest system and uses microfluidic droplets to generate porous microcapsules with easily customizable functionality. The capsules comprise a polymer-gold nanoparticle composite held together by cucurbit[8]uril ternary complexes. The dynamic yet highly stable micrometer-sized structures can be loaded in one step during capsule formation and are amenable to on-demand encapsulant release. The internal chem. environment can be probed with surface enhanced Raman spectroscopy.

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Wiemann, M. ; Jonkheijm, P. Stimuli-Responsive Cucurbit[N]Uril-Mediated Host-Guest Complexes on Surfaces. Isr. J. Chem. 2018, 58 , 314– 325, DOI: 10.1002/ijch.201700109

[Crossref], [CAS], Google Scholar

356

Stimuli-Responsive Cucurbit[n]uril-Mediated Host-Guest Complexes on Surfaces

Wiemann, Maike; Jonkheijm, Pascal

Israel Journal of Chemistry (2018), 58 (3-4), 314-325CODEN: ISJCAT; ISSN:0021-2148. (Wiley-VCH Verlag GmbH & Co. KGaA)

A review. Supramol. functional surfaces are at the heart of many materials and medical applications. Increasing interest can be seen for supramol. functionalization strategies of surfaces. In this review we place particular emphasis on the use of cucurbit[n]uril-mediated host-guest complexation as surface functionalization strategy. The state of the art of cucurbit[n]uril-mediated host-guest complexes on surfaces is reviewed. Cucurbit[n]urils (CB[n]) are able to form strong host-guest complexes with affinities that span several orders of magnitudes up to the regime of the biotin-streptavidin pair. Strategies to fabricate stimuli-responsive surfaces creates versatile supramol. systems and several applications of these types of surfaces are outlined.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVKls7zE&md5=1ee726a0f1ce44b4d34062e0d428f028

357

van Dun, S. ; Ottmann, C. ; Milroy, L. G. ; Brunsveld, L. Supramolecular Chemistry Targeting Proteins. J. Am. Chem. Soc. 2017, 139 , 13960– 13968, DOI: 10.1021/jacs.7b01979

[ACS Full Text ], [CAS], Google Scholar

357

Supramolecular Chemistry Targeting Proteins

van Dun, Sam; Ottmann, Christian; Milroy, Lech-Gustav; Brunsveld, Luc

Journal of the American Chemical Society (2017), 139 (40), 13960-13968CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

A review. The specific recognition of protein surface elements is a fundamental challenge in the life sciences. New developments in this field will form the basis of advanced therapeutic approaches and lead to applications such as sensors, affinity tags, immobilization techniques, and protein-based materials. Synthetic supramol. mols. and materials are creating new opportunities for protein recognition that are orthogonal to classical small mol. and protein-based approaches. As outlined here, their unique mol. features enable the recognition of amino acids, peptides, and even whole protein surfaces, which can be applied to the modulation and assembly of proteins. The authors believe that structural insights into these processes are of great value for the further development of this field and have therefore focused this Perspective on contributions that provide such structural data.

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Nguyen, H. D. ; Dang, D. T. ; van Dongen, J. L. J. ; Brunsveld, L. Protein Dimerization Induced by Supramolecular Interactions with Cucurbit[8]Uril. Angew. Chem., Int. Ed. 2010, 49 , 895– 898, DOI: 10.1002/anie.200904413

[Crossref], [CAS], Google Scholar

358

Protein Dimerization Induced by Supramolecular Interactions with Cucurbit[8]uril

Nguyen, Hoang D.; Dang, Dung T.; van Dongen, Joost L. J.; Brunsveld, Luc

Angewandte Chemie, International Edition (2010), 49 (5), 895-898, S895/1-S895/11CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

The application of supramol. chem. to proteins provides a means of reversibly controlling protein properties. Control over protein dimerization with synthetic mols. is highly desirable, and approaches in which small mols. bind to specific, addnl. incorporated protein domains have been very successful. Control over protein dimerization by means of a very small, genetically encoded peptide motif is an attractive goal in this respect as it would require only very minor protein modifications. Synthetic supramol. host mols. such as the cyclodextrins and cucurbituril have been shown to selectively recognize amino acids, and synthetic receptors have been developed to recognize protein elements, some of which with a high degree of recognition affinity and selectivity. However, synthetic supramol. host mols. have not been applied thus far as inducers of protein dimerization. Herein, it is shown that the supramol. host mol. cucurbit[8]uril can be used to induce and reversibly control the dimerization of proteins having a genetically incorporated N-terminal phenylalanine-glycine-glycine (FGG) peptide motif. The FGG peptide tag is easily incorporated through mol. biol. techniques. The induction of protein dimerization is stable and can be reversed by addn. of a synthetic supramol. guest mol.

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359

Heitmann, L. M. ; Taylor, A. B. ; Hart, P. J. ; Urbach, A. R. Sequence-Specific Recognition and Cooperative Dimerization of N-Terminal Aromatic Peptides in Aqueous Solution by a Synthetic Host. J. Am. Chem. Soc. 2006, 128 , 12574– 12581, DOI: 10.1021/ja064323s

[ACS Full Text ], [CAS], Google Scholar

359

Sequence-specific recognition and cooperative dimerization of N-terminal aromatic peptides in aqueous solution by a synthetic host

Heitmann, Lisa M.; Taylor, Alexander B.; Hart, P. John; Urbach, Adam R.

Journal of the American Chemical Society (2006), 128 (38), 12574-12581CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

This article describes the selective recognition and noncovalent dimerization of N-terminal arom. peptides in aq. soln. by the synthetic host compd., cucurbit[8]uril (Q8). Q8 is known to bind two arom. guests simultaneously and, in the presence of Me viologen, to recognize N-terminal tryptophan over internal and C-terminal sequence isomers. Here, the binding of Q8 to arom. peptides in the absence of Me viologen was studied by isothermal titrn. calorimetry (ITC), 1H NMR spectroscopy, and X-ray crystallog. The peptides studied were of sequence X-Gly-Gly, Gly-X-Gly, and Gly-Gly-X (X = Trp, Phe, Tyr, and His). Q8 selectively binds and dimerizes Trp-Gly-Gly (1) and Phe-Gly-Gly (4) with high affinity (ternary K = 109-1011 M-2); binding consts. for the other 10 peptides were too small to be measured by ITC. Both peptides bound in a stepwise manner, and peptide 4 bound with pos. cooperativity. Crystal structures of Q8·1 and Q8·42 reveal the basis for selective recognition as simultaneous inclusion of the hydrophobic arom. side chain into the cavity of Q8 and chelation of the proximal N-terminal ammonium group by carbonyl groups of Q8. The peptide sequence selectivity and pos. cooperative dimerization reported here are, to the best of our knowledge, unprecedented for synthetic hosts in aq. soln. Specific peptide recognition and dimerization by synthetic hosts such as Q8 should be important in the study of dimer-mediated biochem. processes and for the sepn. of peptides and proteins.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XptFaisLw%253D&md5=a1ee16d43d15cb42298d6c5bf8140959

360

de Vink, P. J. ; Briels, J. M. ; Schrader, T. ; Milroy, L. G. ; Brunsveld, L. ; Ottmann, C. A Binary Bivalent Supramolecular Assembly Platform Based on Cucurbit[8]Uril and Dimeric Adapter Protein 14–3-3. Angew. Chem., Int. Ed. 2017, 56 , 8998– 9002, DOI: 10.1002/anie.201701807

[Crossref], [CAS], Google Scholar

360

A binary bivalent supramolecular assembly platform based on cucurbit[8]uril and dimeric adapter protein 14-3-3

de Vink, Pim J.; Briels, Jeroen M.; Schrader, Thomas; Milroy, Lech-Gustav; Brunsveld, Luc; Ottmann, Christian

Angewandte Chemie, International Edition (2017), 56 (31), 8998-9002CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)

Interactions between proteins frequently involve recognition sequences based on multivalent binding events. Dimeric 14-3-3 adapter proteins are a prominent example and typically bind partner proteins in a phosphorylation-dependent monovalent or bivalent manner. Here, we describe the development of a cucurbit[8]uril (Q8)-based supramol. system, which in conjunction with the 14-3-3β protein dimer acts as a binary and bivalent protein assembly platform. We fused the Phe-Gly-Gly (FGG) tripeptide motif to the N-terminus of the 14-3-3-binding epitope of the estrogen receptor α (ERα) for selective binding to Q8. Q8-induced dimerization of the ERα epitope augmented its affinity towards 14-3-3β through a binary bivalent binding mode. The crystal structure of the Q8-induced ternary complex revealed mol. insight into the multiple supramol. interactions between the protein, the peptide, and Q8.

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361

Guo, D.-S. ; Wang, K. ; Liu, Y. Selective Binding Behaviors of P-Sulfonatocalixarenes in Aqueous Solution. J. Inclusion Phenom. Mol. Recognit. Chem. 2008, 62 , 1– 21, DOI: 10.1007/s10847-008-9452-2

[Crossref], [CAS], Google Scholar

361

Selective binding behaviors of p-sulfonatocalixarenes in aqueous solution

Guo, Dong-Sheng; Wang, Kui; Liu, Yu

Journal of Inclusion Phenomena and Macrocyclic Chemistry (2008), 62 (1-2), 1-21CODEN: JIPCF5; ISSN:1388-3127. (Springer)

A review. The complex structures, binding abilities, mol. selectivities, and thermodn. origin of p-sulfonatocalixarenes upon complexation with kinds of guests are outlined in this review article, including inorg. cations, org. ammonium cations, pyridiniums and viologens, neutral org. mols., dye mols., and others. Calorimetric and spectroscopic investigations afford the complex stability consts., thermodn. parameters and binding manners of the inclusion complexation of p-sulfonatocalixarenes with guest mols. The π-stacking, hydrophobic and charge interactions are the main driving-forces during the course of the host-guest inclusion complexation. The mol. binding abilities and selectivities are influenced by not only the frameworks of calixarene cavities, structures of guest mols., and their binding manners but also the conditions of solns. (mainly pH), which are discussed from the correlation between the structural features and mol.-recognition abilities. Moreover, the further applications and potentials of p-sulfonatocalixarenes are briefly described.

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362

Guo, D.-S. ; Liu, Y. Supramolecular Chemistry of P-Sulfonatocalix[N]Arenes and Its Biological Applications. Acc. Chem. Res. 2014, 47 , 1925– 1934, DOI: 10.1021/ar500009g

[ACS Full Text ], [CAS], Google Scholar

362

Supramolecular Chemistry of p-Sulfonatocalix[n]arenes and Its Biological Applications

Guo, Dong-Sheng; Liu, Yu

Accounts of Chemical Research (2014), 47 (7), 1925-1934CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review. Developments in macrocyclic chem. led to supramol. chem., a field that has attracted increasing attention among researchers in various disciplines. Notably, the discoveries of new types of macrocyclic hosts have served as important milestones in the field. Researchers have explored the supramol. chem. of several classical macrocyclic hosts, including crown ethers, cyclodextrins, calixarenes, and cucurbiturils. Calixarenes represent a third generation of supramol. hosts after cyclodextrins and crown ethers. Easily modified, these macrocycles show great potential as simple scaffolds to build podand-like receptors. However, the inclusion properties of the cavities of unmodified calixarenes are not as good as those of other common macrocycles. Calixarenes require extensive chem. modifications to achieve efficient endo-complexation. P-Sulfonatocalix[n]arenes (SCnAs, n = 4-8) are a family of water-sol. calixarene derivs. that in aq. media bind to guest mols. in their cavities. Their cavities are three-dimensional and π-electron-rich with multiple sulfonate groups, which endow them with fascinating affinities and selectivities, esp. toward org. cations. They also can serve as scaffolds for functional, responsive host-guest systems. Moreover, SCnAs are biocompatible, which makes them potentially useful for diverse life sciences and pharmaceutical applications. In this Account, the authors summarize recent work on the recognition and assembly properties unique to SCnAs and their potential biol. applications, by the authors' group and by other labs. Initially examg. simple host-guest systems, the authors describe the development of a series of functional host-guest pairs based on the mol. recognition between SCnAs and guest mols. Such pairs can be used for fluorescent sensing systems, enzymic activity assays, and pesticide detoxification. Although most macrocyclic hosts prevent self-aggregation of guest mols., SCnAs can induce self-aggregation. Researchers have exploited calixarene-induced aggregation to construct supramol. binary vesicles. These vesicles respond to internal and external stimuli, including temp. changes, redox reactions, additives, and enzymic reactions. Such structures could be used as drug delivery vehicles. Although several biol. applications of SCnAs have been reported, this field is still in its infancy. Continued exploration of the supramol. chem. of SCnAs will not only improve the existing biol. functions but also open new avenues for the use of SCnAs in the fields of biol., biotechnol., and pharmaceutical research. In addn., the authors expect that other interdisciplinary research efforts will accelerate developments in the supramol. chem. of SCnAs.

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Ghale, G. ; Nau, W. M. Dynamically Analyte-Responsive Macrocyclic Host–Fluorophore Systems. Acc. Chem. Res. 2014, 47 , 2150– 2159, DOI: 10.1021/ar500116d

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363

Dynamically Analyte-Responsive Macrocyclic Host-Fluorophore Systems

Ghale, Garima; Nau, Werner M.

Accounts of Chemical Research (2014), 47 (7), 2150-2159CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review. Host-guest chem. commenced to a large degree with the work of Pedersen, who in 1967 first reported the synthesis of crown ethers. The past 45 years have witnessed a substantial progress in the field, from the design of highly selective host mols. as receptors to their application in drug delivery and, particularly, analyte sensing. Much effort has been expended on designing receptors and signaling mechanism for detecting compds. of biol. and environmental relevance. Traditionally, the design of a chemosensor comprises one component for mol. recognition, frequently macrocycles of the cyclodextrin, cucurbituril, cyclophane, or calixarene type. The second component, used for signaling, is typically an indicator dye which changes its photophys. properties, preferably its fluorescence, upon analyte binding. A variety of signal transduction mechanisms are available, of which displacement of the dye from the macrocyclic binding site is one of the simplest and most popular ones. This constitutes the working principle of indicator displacement assays. However, indicator displacement assays have been predominantly exploited in a static fashion, namely, to det. abs. analyte concns., or, by using combinations of several reporter pairs, to achieve a differential sensing and, thus, identification of specific food products or brands. In contrast, their use in biol. systems, for example, with membranes, cells, or with enzymes has been comparably less explored, which led the authors to the design of the so-called tandem assays, i.e., dynamically analyte-responsive host-dye systems, in which the change in analyte concns. is induced by a biol. reaction or process. This methodol. variation has practical application potential, because the ability to monitor these biochem. pathways or to follow specific mols. in real time is of paramount interest for both biochem. labs. and the pharmaceutical industry. The authors will begin by describing the underlying principles that govern the use of macrocycle-fluorescent dye complexes to monitor time-dependent changes in analyte concns. Suitable chemosensing ensembles are introduced, along with their fluorescence responses (switch-on or switch-off). This includes supramol. tandem assays in their product- and substrate-selective variants, and in their domino and enzyme-coupled modifications, with assays for amino acid decarboxylases, diamine, and choline oxidase, proteases, Me transferases, acetylcholinesterase (including an unpublished direct tandem assay), choline oxidase, and potato apyrase as examples. It also includes the very recently introduced tandem membrane assays in their published influx and unpublished efflux variants, with the outer membrane protein F as channel protein and protamine as bidirectionally translocated analyte. As proof-of-principle for environmental monitoring applications, the authors describe sensing ensembles for volatile hydrocarbons.

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Hof, F. Host–Guest Chemistry That Directly Targets Lysine Methylation: Synthetic Host Molecules as Alternatives to Bio-Reagents. Chem. Commun. 2016, 52 , 10093– 10108, DOI: 10.1039/C6CC04771H

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364

Host-guest chemistry that directly targets lysine methylation: synthetic host molecules as alternatives to bio-reagents

Hof, Fraser

Chemical Communications (Cambridge, United Kingdom) (2016), 52 (66), 10093-10108CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)

A review. Post-translational methylation is a chem. simple modification, but regulates the function of hundreds of proteins in profound ways. This Feature Article will report on the basic aspects of protein methylation, and will offer a personal perspective on our recent efforts at making supramol. hosts that can bind and discriminate among post-translationally methylated partners. The article highlights several general lessons drawn from these efforts and related work by other groups. It also describes some ways in which supramol. approaches are inherently well suited to provide tools that drive new research in the life sciences.

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Romero, M. A. ; Mateus, P. ; Matos, B. ; Acuna, A. ; Garcia-Rio, L. ; Arteaga, J. F. ; Pischel, U. ; Basílio, N. Binding of Flavylium Ions to Sulfonatocalix[4]Arene and Implication in the Photorelease of Biologically Relevant Guests in Water. J. Org. Chem. 2019, 84 , 10852– 10859, DOI: 10.1021/acs.joc.9b01420

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365

Binding of Flavylium Ions to Sulfonatocalix[4]arene and Implication in the Photorelease of Biologically Relevant Guests in Water

Romero, Miguel A.; Mateus, Pedro; Matos, Beatriz; Acuna, Angel; Garcia-Rio, Luis; Arteaga, Jesus F.; Pischel, Uwe; Basilio, Nuno

Journal of Organic Chemistry (2019), 84 (17), 10852-10859CODEN: JOCEAH; ISSN:0022-3263. (American Chemical Society)

The formation of host-guest complexes between seven flavylium cations and water-sol. p-sulfonatocalix[4]arene (SC4) was investigated by UV/vis absorption, fluorescence, and NMR spectroscopies. The results show the cationic guests form complexes with affinities in the submillimolar range. A representative chalcone/flavylium photoswitch was investigated in more detail regarding its pH- and light-triggered interconversion between the two forms. The dramatic affinity differentiation of the SC4 binding of the two switchable species (40 M-1 for the trans-chalcone vs. 3.5 × 104 M-1 for the flavylium cation) enables the pH-gated photocontrol of the complexation process. These responsive properties were explored to demonstrate the competitive and selective release of biol. relevant guests from their supramol. complexes with p-sulfonatocalix[4]arene (SC4), following the principle of AND logic. The guest release can be reverted by the thermally activated reaction of the flavylium ion back to the trans-chalcone.

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Baroncini, M. ; Silvi, S. ; Credi, A. Photo- and Redox-Driven Artificial Molecular Motors. Chem. Rev. 2020, 120 , 200– 268, DOI: 10.1021/acs.chemrev.9b00291

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366

Photo- and Redox-Driven Artificial Molecular Motors

Baroncini, Massimo; Silvi, Serena; Credi, Alberto

Chemical Reviews (Washington, DC, United States) (2020), 120 (1), 200-268CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. Directed motion at the nanoscale is a central attribute of life, and chem. driven motor proteins are nature's choice to accomplish it. Motivated and inspired by such bionanodevices, in the past few decades chemists have developed artificial prototypes of mol. motors, namely, multicomponent synthetic species that exhibit directionally controlled, stimuli-induced movements of their parts. In this context, photonic and redox stimuli represent highly appealing modes of activation, particularly from a technol. viewpoint. Here we describe the evolution of the field of photo- and redox-driven artificial mol. motors, and we provide a comprehensive review of the work published in the past 5 years. After an anal. of the general principles that govern controlled and directed movement at the mol. scale, we describe the fundamental photochem. and redox processes that can enable its realization. The main classes of light- and redox-driven mol. motors are illustrated, with a particular focus on recent designs, and a thorough description of the functions performed by these kinds of devices according to literature reports is presented. Limitations, challenges, and future perspectives of the field are critically discussed.

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Erbas-Cakmak, S. ; Leigh, D. A. ; McTernan, C. T. ; Nussbaumer, A. L. Artificial Molecular Machines. Chem. Rev. 2015, 115 , 10081– 10206, DOI: 10.1021/acs.chemrev.5b00146

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367

Artificial Molecular Machines

Erbas-Cakmak, Sundus; Leigh, David A.; McTernan, Charlie T.; Nussbaumer, Alina L.

Chemical Reviews (Washington, DC, United States) (2015), 115 (18), 10081-10206CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

This paper reviews triggered large-amplitude motions in mol. structures and the changes in properties these can produce. The focus is on conformational and configurational changes in wholly covalently bonded mols. and on catenanes and rotaxanes in which switching is brought about by various stimuli. Also discussed is the latest generations of sophisticated synthetic mol. machine systems in which the controlled motion of subcomponents is used to perform complex tasks, paving the way to applications and the realization of a new era of "mol. nanotechnol.".

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Pezzato, C. ; Cheng, C. Y. ; Stoddart, J. F. ; Astumian, R. D. Mastering the Non-Equilibrium Assembly and Operation of Molecular Machines. Chem. Soc. Rev. 2017, 46 , 5491– 5507, DOI: 10.1039/C7CS00068E

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368

Mastering the non-equilibrium assembly and operation of molecular machines

Pezzato, Cristian; Cheng, Chuyang; Stoddart, J. Fraser; Astumian, R. Dean

Chemical Society Reviews (2017), 46 (18), 5491-5507CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

In mech. interlocked compds., such as rotaxanes and catenanes, the mols. are held together by mech. rather than chem. bonds. These compds. can be engineered to have several well-defined mech. states by incorporating recognition sites between the different components. The rates of the transitions between the recognition sites can be controlled by introducing steric "speed bumps" or electrostatically switchable gates. A mechanism for the absorption of energy can also be included by adding photoactive, catalytically active, or redox-active recognition sites, or even charges and dipoles. At equil., these Mech. Interlocked Mols. (MIMs) undergo thermally activated transitions continuously between their different mech. states where every transition is as likely as its microscopic reverse. External energy, for example, light, external modulation of the chem. and/or phys. environment or catalysis of an exergonic reaction, drives the system away from equil. The absorption of energy from these processes can be used to favor some, and suppress other, transitions so that completion of a mech. cycle in a direction in which work is done on the environment - the requisite of a mol. machine - is more likely than completion in a direction in which work is absorbed from the environment. In this Tutorial Review, we discuss the different design principles by which mol. machines can be engineered to use different sources of energy to carry out self-organization and the performance of work in their environments.

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Coskun, A. ; Spruell, J. M. ; Barin, G. ; Dichtel, W. R. ; Flood, A. H. ; Botros, Y. Y. ; Stoddart, J. F. High Hopes: Can Molecular Electronics Realise Its Potential?. Chem. Soc. Rev. 2012, 41 , 4827– 4859, DOI: 10.1039/c2cs35053j

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369

High hopes: Can molecular electronics realize its potential?

Coskun, Ali; Spruell, Jason M.; Barin, Gokhan; Dichtel, William R.; Flood, Amar H.; Botros, Youssry Y.; Stoddart, J. Fraser

Chemical Society Reviews (2012), 41 (14), 4827-4859CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Manipulating and controlling the self-organization of small collections of mols., as an alternative to investigating individual mols., has motivated researchers bent on processing and storing information in mol. electronic devices (MEDs). Although numerous ingenious examples of single-mol. devices have provided fundamental insights into their mol. electronic properties, MEDs incorporating hundreds to thousands of mols. trapped between wires in two-dimensional arrays within crossbar architectures offer a glimmer of hope for mol. memory applications. In this crit. review, we focus attention on the collective behavior of switchable mech. interlocked mols. (MIMs)-specifically, bistable rotaxanes and catenanes-which exhibit reset lifetimes between their ON and OFF states ranging from seconds in soln. to hours in crossbar devices. When these switchable MIMs are introduced into high viscosity polymer matrixes, or self-assembled as monolayers onto metal surfaces, both in the form of nanoparticles and flat electrodes, or organized as tightly packed islands of hundreds and thousands of mols. sandwiched between two electrodes, the thermodn. which characterize their switching remain approx. const. while the kinetics assocd. with their reset follow an intuitively predictable trend-i.e., fast when they are free in soln. and sluggish when they are constrained within closely packed monolayers. The importance of seamless interactions and const. feedback between the makers, the measurers and the modelers in establishing the structure-property relationships in these integrated functioning systems cannot be stressed enough as rationalizing the many different factors that impact device performance becomes more and more demanding. The choice of electrodes, as well as the self-organized superstructures of the monolayers of switchable MIMs employed in the mol. switch tunnel junctions (MSTJs) assocd. with the crossbars of these MEDs, have a profound influence on device operation and performance. It is now clear, after much investigation, that a distinction should be drawn between two types of switching that can be elicited from MSTJs. One affords small ON/OFF ratios and is a direct consequence of the switching in bistable MIMs that leads to a relatively small remnant mol. signature-an activated chem. process. The other leads to a very much larger signature and ON/OFF ratios resulting from phys. or chem. changes in the electrodes themselves. Control expts. with various compds., including degenerate catenanes and free dumbbells, which cannot and do not switch, are crucial in establishing the authenticity of the small ON/OFF ratios and remnant mol. signatures produced by bistable MIMs. Moreover, expts. conducted on monolayers in MSTJs of mols. designed to switch and mols. designed not to switch have been probed directly by spectroscopic and other means in support of MEDs that store information through switching collections of bistable MIMs contained in arrays of MSTJs. In the quest for the next generation of MEDs, it is likely that monolayers of bistable MIMs will be replaced by robust cryst. extended structures wherein the switchable components, derived from bistable MIMs, are organized precisely in a periodic manner.

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Bruns, C. J. ; Stoddart, J. F. Rotaxane-Based Molecular Muscles. Acc. Chem. Res. 2014, 47 , 2186– 2199, DOI: 10.1021/ar500138u

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370

Rotaxane-Based Molecular Muscles

Bruns, Carson J.; Stoddart, J. Fraser

Accounts of Chemical Research (2014), 47 (7), 2186-2199CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

A review. More than two decades of investigating the chem. of bistable mech. interlocked mols. (MIMs), such as rotaxanes and catenanes, has led to the advent of numerous mol. switches that express controlled translational or circumrotational movement on the nanoscale. Directed motion at this scale is an essential feature of many biomol. assemblies known as mol. machines, which carry out essential life-sustaining functions of the cell. It follows that the use of bistable MIMs as artificial mol. machines (AMMs) has been long anticipated. This objective is rarely achieved, however, because of challenges assocd. with coupling the directed motions of mech. switches with other systems on which they can perform work. A natural source of inspiration for designing AMMs is muscle tissue, since it is a material that relies on the hierarchical organization of mol. machines (myosin) and filaments (actin) to produce the force and motion that underpin locomotion, circulation, digestion, and many other essential life processes in humans and other animals. Muscle is characterized at both microscopic and macroscopic length scales by its ability to generate forces that vary the distance between two points at the expense of chem. energy. Artificial muscles that mimic this ability are highly sought for applications involving the transduction of mech. energy. Rotaxane-based mol. switches are excellent candidates for artificial muscles because their architectures intrinsically possess movable filamentous mol. components. In this Account, we describe (i) the different types of rotaxane "mol. muscle" architectures that express contractile and extensile motion, (ii) the mol. recognition motifs and corresponding stimuli that have been used to actuate them, and (iii) the progress made on integrating and scaling up these motions for potential applications. We identify three types of rotaxane muscles, namely, "daisy chain", "press", and "cage" rotaxanes, and discuss their mech. actuation driven by ions, pH, light, solvents, and redox stimuli. Different applications of these rotaxane-based mol. muscles are possible at various length scales. On a mol. level, they have been harnessed to create adjustable receptors and to control electronic communication between chem. species. On the mesoscale, they have been incorporated into artificial muscle materials that amplify their concerted motions and forces, making future applications at macroscopic length scales look feasible. We emphasize how rotaxanes constitute a remarkably versatile platform for directing force and motion, owing to the wide range of stimuli that can be used to actuate them and their diverse modes of mech. switching as dictated by the stereochem. of their mech. bonds, i.e., their mechanostereochem. We hope that this Account will serve as an exposition that sets the stage for new applications and materials that exploit the capabilities of rotaxanes to transduce mech. energy and help in paving the path going forward to genuine AMMs.

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Blanco, V. ; Leigh, D. A. ; Marcos, V. Artificial Switchable Catalysts. Chem. Soc. Rev. 2015, 44 , 5341– 5370, DOI: 10.1039/C5CS00096C

[Crossref], [PubMed], [CAS], Google Scholar

371

Artificial switchable catalysts

Blanco, Victor; Leigh, David A.; Marcos, Vanesa

Chemical Society Reviews (2015), 44 (15), 5341-5370CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. Catalysis is key to the effective and efficient transformation of readily available building blocks into high value functional mols. and materials. For many years research in this field has largely focused on the invention of new catalysts and the optimization of their performance to achieve high conversions and/or selectivities. However, inspired by Nature, chemists are beginning to turn their attention to the development of catalysts whose activity in different chem. processes can be switched by an external stimulus. Potential applications include using the states of multiple switchable catalysts to control sequences of transformations, producing different products from a pool of building blocks according to the order and type of stimuli applied. Here we outline the state-of-art in artificial switchable catalysis, classifying systems according to the trigger used to achieve control over the catalytic activity and stereochem. or other structural outcomes of the reaction.

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Chen, W. ; Glackin, C. A. ; Horwitz, M. A. ; Zink, J. I. Nanomachines and Other Caps on Mesoporous Silica Nanoparticles for Drug Delivery. Acc. Chem. Res. 2019, 52 , 1531– 1542, DOI: 10.1021/acs.accounts.9b00116

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372

Nanomachines and Other Caps on Mesoporous Silica Nanoparticles for Drug Delivery

Chen, Wei; Glackin, Carlotta A.; Horwitz, Marcus A.; Zink, Jeffrey I.

Accounts of Chemical Research (2019), 52 (6), 1531-1542CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)

Mesoporous silica nanoparticles (MSNs) are delivery vehicles that can carry cargo mols. and release them on command. The particles used in the applications reported in this Account are around 100 nm in diam. (about the size of a virus) and contain 2.5 nm tubular pores with a total vol. of about 1 cm3/g. For the biomedical applications discussed here, the cargo is trapped in the pores until the particles are stimulated to release it. The challenges are to get the particles to the site of a disease and then to deliver the cargo on command. We describe methods to do both, and we illustrate the applicability of the particles to cure cancer and intracellular infectious disease.Our first steps were to design multifunctional nanoparticles with properties that allow them to carry and deliver hydrophobic drugs. Many important pharmaceuticals are hydrophobic and cannot reach the diseased sites by themselves. We describe how we modified MSNs to make them dispersible, imagable, and targetable and discuss in vitro studies. We then present examples of surface modifications that allow them to deliver large mols. such as siRNA. In vivo studies of siRNA delivery to treat triple-neg. breast and ovarian cancers are presented.The next steps are to attach nanomachines and other types of caps that trap drug mols. but release them when stimulated. We describe nanomachines that respond autonomously (without human intervention) to stimuli specific to disease sites. A versatile type of machine is a nanovalve that is closed at neutral (blood) pH but opens upon acidification that occurs in endolysosomes of cancer cells. Another type of machine, a snap-top cap, is stimulated by reducing agents such as glutathione in the cytosol of cells. Both of these platforms were studied in vitro to deliver antibiotics to infected macrophages and in vivo to cure and kill the intracellular bacteria M. tuberculosis and F. tularensis. The latter is a tier 1 select agent of bioterrorism.Finally, we describe nanomachines for drug delivery that are controlled by externally administered light and magnetic fields. A futuristic dream for nanotherapy is the ability to control a nano-object everywhere in the body. Magnetic fields penetrate completely and have spatial selectivity governed by the size of the field-producing coil. We describe how to control nanovalves with alternating magnetic fields (AMFs) and superparamagnetic cores inside the MSNs. The AMF heats the cores, and temp.-sensitive caps release the cargo. In vitro studies demonstrate dose control of the therapeutic to cause apoptosis without overheating the cells. Nanocarriers have great promise for therapeutic applications, and MSNs that can carry drugs to the site of a disease to produce a high local concn. without premature release and off-target damage may have the capability of realizing this goal.

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Li, Z. X. ; Barnes, J. C. ; Bosoy, A. ; Stoddart, J. F. ; Zink, J. I. Mesoporous Silica Nanoparticles in Biomedical Applications. Chem. Soc. Rev. 2012, 41 , 2590– 2605, DOI: 10.1039/c1cs15246g

[Crossref], [PubMed], [CAS], Google Scholar

373

Mesoporous silica nanoparticles in biomedical applications

Li, Zongxi; Barnes, Jonathan C.; Bosoy, Aleksandr; Stoddart, J. Fraser; Zink, Jeffrey I.

Chemical Society Reviews (2012), 41 (7), 2590-2605CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

This tutorial review provides an outlook on nanomaterials that are currently being used for theranostic purposes, with a special focus on mesoporous silica nanoparticle (MSNP) based materials. MSNPs with large surface area and pore vol. can serve as efficient carriers for various therapeutic agents. The functionalization of MSNPs with mol., supramol. or polymer moieties, provides the material with great versatility while performing drug delivery tasks, which makes the delivery process highly controllable. This emerging area at the interface of chem. and the life sciences offers a broad palette of opportunities for researchers with interests ranging from sol-gel science, the fabrication of nanomaterials, supramol. chem., controllable drug delivery and targeted theranostics in biol. and medicine.

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374

Ma, X. ; Tian, H. Bright Functional Rotaxanes. Chem. Soc. Rev. 2010, 39 , 70– 80, DOI: 10.1039/B901710K

[Crossref], [PubMed], [CAS], Google Scholar

374

Bright functional rotaxanes

Ma, Xiang; Tian, He

Chemical Society Reviews (2010), 39 (1), 70-80CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

A review. As a hot topic in research, various rotaxanes continue to be constructed. This tutorial review focuses mainly on bright rotaxanes with functional properties, which have been developed in recent years: fluorescent rotaxanes, rotaxanes as logic gates and information storage devices, gelation of rotaxanes, rotaxanes on solid surfaces, sensory rotaxanes, as well as rotaxanes related to biol. and so on. Novel synthetic protocols towards several functional rotaxanes are also illustrated.

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375

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375

Nano/microencapsulation of anthocyanins; a systematic review and meta-analysis

Sharif, Niloufar; Khoshnoudi-Nia, Sara; Jafari, Seid Mahdi

Food Research International (2020), 132 (), 109077CODEN: FORIEU; ISSN:0963-9969. (Elsevier B.V.)

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Cortez, R. ; Luna-Vital, D. A. ; Margulis, D. ; de Mejia, E. G. Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications. Compr. Rev. Food Sci. Food Saf. 2017, 16 , 180– 198, DOI: 10.1111/1541-4337.12244

[Crossref], [PubMed], [CAS], Google Scholar

376

Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications

Cortez, Regina; Luna-Vital, Diego A.; Margulis, Daniel; Gonzalez de Mejia, Elvira

Comprehensive Reviews in Food Science and Food Safety (2017), 16 (1), 180-198CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)

A review. The prodn. of natural food pigments continues to grow worldwide. The global market is expected to grow at a compd. annual growth rate of 6.22%, by revenue, over the period 2015 to 2019. Pigments such as anthocyanins, carotenoids, betalains, and chlorophylls have been used to color foods. However, there are challenges related to color losses during food processing, storage, and commercialization due to a low stability of natural pigments compared to synthetic colorants. This review summarizes the most recent studies and patents aimed at enhancing anthocyanin stability in food systems. The stabilizing methods include addns. of copigment compds., such as polymers, phenolic compds., and metals. In addn., the exclusion of O2 during processing and storage, hard-panned candy coating methods for blue, green, and brown colors, and various encapsulation techniques were considered. Combining strategies and evaluating new materials capable of stabilizing anthocyanins will enhance their potential for use as value-added natural food pigments.

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377

Silva, G. T. M. ; Silva, K. M. ; Silva, C. P. ; Gonçalves, J. M. ; Quina, F. H. Hybrid Pigments from Anthocyanin Analogues and Synthetic Clay Minerals. ACS Omega 2020, 5 , 26592– 26600, DOI: 10.1021/acsomega.0c03354

[ACS Full Text ], [CAS], Google Scholar

377

Hybrid Pigments from Anthocyanin Analogues and Synthetic Clay Minerals

Silva, Gustavo Thalmer M.; Silva, Karen Magno; Silva, Cassio P.; Goncalves, Josue M.; Quina, Frank H.

ACS Omega (2020), 5 (41), 26592-26600CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)

Flavylium cations are synthetic analogs of anthocyanins, the natural plant pigments that are responsible for the majority of the red, blue, and purple colors of flowers, fruits, and leaves. Unlike anthocyanins, the properties and reactivity of flavylium cations can be manipulated by the nature and position of substituents on the flavylium cation chromophore. Currently, the most promising strategies for stabilizing the color of anthocyanins and flavylium cations appear to be to intercalate and/or adsorb them on solid surfaces and/or in confined spaces. We report here that hybrid pigments with improved thermal stability, fluorescence, and attractive colors are produced by the cation-exchange-mediated adsorption of flavylium cations (FL) on two synthetic clays, the mica-montmorillonite SYn-1, and the laponite SYnL-1. Compared to the FL/SYn-1 hybrid pigments, the FL/SYnL-1 pigments exhibited improved thermal stability as judged by color retention, better preferential adsorption of the cationic form of FL1 at neutral to mildly basic pH (pH 7-8), and lower susceptibility to color changes at pH 10. Although both clays adsorb the cationic form on their external surfaces, SYnL-1 gave more evidence of adsorption in the interlayer regions of the clay. This interlayer adsorption appears to be the contributing factor to the better properties of the FL/SYnL-1 hybrid pigments, pointing to this clay to be a promising inorg. matrix for the development of brightly colored, thermally more stable hybrid pigments based on cationic analogs of natural plant pigments.

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378

Kohno, Y. ; Shibata, Y. ; Oyaizu, N. ; Yoda, K. ; Shibata, M. ; Matsushima, R. Stabilization of Flavylium Dye by Incorporation into the Pore of Protonated Zeolites. Microporous Mesoporous Mater. 2008, 114 , 373– 379, DOI: 10.1016/j.micromeso.2008.01.023

[Crossref], [CAS], Google Scholar

378

Stabilization of flavylium dye by incorporation into the pore of protonated zeolites

Kohno, Yoshiumi; Shibata, Yoshinori; Oyaizu, Nobuyuki; Yoda, Keiko; Shibata, Masashi; Matsushima, Ryoka

Microporous and Mesoporous Materials (2008), 114 (1-3), 373-379CODEN: MIMMFJ; ISSN:1387-1811. (Elsevier)

Flavylium dye, a model compd. of natural anthocyanin, has a defect that its color stability is very poor. We have complexed the flavylium dye with protonated zeolites and succeeded to enhance both the thermal and chem. stability of the dye. The aq. dispersion of the flavylium/zeolite complex maintains its color even at 353 K or at pH 9, under which conditions the aq. soln. of the flavylium loses its color immediately. The stability is enhanced when the dye is incorporated into the pore of the zeolites, and a large stabilization effect is obtained by a tight adsorption with a narrow pore, as long as the dye is incorporated into the pore. Because of its enhanced color stability, the flavylium dye incorporated in the zeolite pore can be a candidate for an environmentally friendly coloring material.

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379

Gago, S. ; Pessêgo, M. ; Laia, C. A. T. ; Parola, A. J. Ph-Tunable Fluorescence and Photochromism of a Flavylium-Based Mcm-41 Pigment. ACS Omega 2017, 2 , 122– 126, DOI: 10.1021/acsomega.6b00381

[ACS Full Text ], [CAS], Google Scholar

379

pH-Tunable Fluorescence and Photochromism of a Flavylium-Based MCM-41 Pigment

Gago, Sandra; Pessego, Marcia; Laia, Cesar A. T.; Parola, A. Jorge

ACS Omega (2017), 2 (1), 122-126CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)

Incorporation of flavylium-derived chalcones in the CTAB-templated synthesis of mesoporous silica particles with no subsequent removal of the micellar phase leads to highly luminescence (0.3<Φf<0.5) and strong color contrast photochromic pigments finely tunable over a large pH range (1<pH<11).

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380

Brandão Lima, L. C. ; Castro-Silva, F. ; Silva-Filho, E. C. ; Fonseca, M. G. ; Jaber, M. Saponite-Anthocyanin Pigments: Slipping between the Sheets. Microporous Mesoporous Mater. 2020, 300 , 110148, DOI: 10.1016/j.micromeso.2020.110148

[Crossref], [CAS], Google Scholar

380

Saponite-anthocyanin pigments: Slipping between the sheets

Brandao Lima, Luciano Clecio; Castro-Silva, Fabricia; Silva-Filho, Edson Cavalcanti; Fonseca, Maria Gardennia; Jaber, Maguy

Microporous and Mesoporous Materials (2020), 300 (), 110148CODEN: MIMMFJ; ISSN:1387-1811. (Elsevier B.V.)

The present work describes the synthesis and characterization of hybrid materials based on β-cyclodextrin (β-CD) and cetyltrimethylammonium bromide (CTAB) intercalated into saponite (SAP) and a com. available powder of anthocyanin dye, Crystal Red Grape (RG). The interactions between the org. dye guest and the organo-clay host were studied by x-ray diffraction, TGA, transmission electronic microscopy and 13C solid state NMR. The results support complex formation between β-CD and CTAB, their intercalation into the clay interlayer spaces or surface loading, and their interaction with RG (CTAB_SAP-RG, β-CD_SAP-RG and β-CD + CTAB_SAP-RG). The hybrid pigments formed exhibit different colors, enhanced stability against visible light irradn. and basic pH conditions. These hybrid pigments are environmentally friendly and can be promising candidates in different application fields.

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381

Silva, G. T. M. ; Silva, C. P. ; Gehlen, M. H. ; Oake, J. ; Bohne, C. ; Quina, F. H. Organic/Inorganic Hybrid Pigments from Flavylium Cations and Palygorskite. Appl. Clay Sci. 2018, 162 , 478– 486, DOI: 10.1016/j.clay.2018.07.002

[Crossref], [CAS], Google Scholar

381

Organic/inorganic hybrid pigments from flavylium cations and palygorskite

Silva, Gustavo Thalmer M.; Silva, Cassio P.; Gehlen, Marcelo H.; Oake, Jessy; Bohne, Cornelia; Quina, Frank H.

Applied Clay Science (2018), 162 (), 478-486CODEN: ACLSER; ISSN:0169-1317. (Elsevier B.V.)

Features such as color, brightness and fluorescence are extremely important in applications of pigments. Hybrid materials inspired by the ancient Maya Blue pigment are a promising alternative to improve the properties and applicability of natural and synthetic dyes. In this work, we report the prepn., photophys. properties, and stability of several fluorescent hybrid pigments based on flavylium cations (FL) adsorbed on palygorskite (PAL). Five flavylium cations were investigated, viz., the 3',4',7-trimethoxyflavylium (FL1), 7-hydroxy-4'-methoxy-flavylium (FL2), 7-hydroxy-4-methylflavylium (FL3), 5,7-dihydroxy-4-methylflavylium (FL4) and 7-methoxy-4-methylflavylium (FL5) cations. Only FL1 and FL2, without a Me substituent at the 4-position that could hinder inclusion in palygorskite channels, adsorbed strongly on PAL, producing fluorescent hybrid pigments with attractive colors. The spectroscopic and fluorescence properties of the FL1/PAL and FL2/PAL hybrid pigments were characterized. The color of the adsorbed dyes was somewhat more resistant to changes in external pH, photochem. stability was maintained and the thermal lability was markedly improved in the FL/PAL hybrid pigments, pointing to flavylium cations as promising chromophores for the development of fluorescent hybrid pigments with attractive colors.

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382

Silva, G. T. M. ; da Silva, K. M. ; Silva, C. P. ; Rodrigues, A. C. B. ; Oake, J. ; Gehlen, M. H. ; Bohne, C. ; Quina, F. H. Highly Fluorescent Hybrid Pigments from Anthocyanin- and Red Wine Pyranoanthocyanin-Analogs Adsorbed on Sepiolite Clay. Photochem. Photobiol. Sci. 2019, 18 , 1750– 1760, DOI: 10.1039/C9PP00141G

[Crossref], [PubMed], [CAS], Google Scholar

382

Highly fluorescent hybrid pigments from anthocyanin- and red wine pyranoanthocyanin-analogs adsorbed on sepiolite clay

Silva, Gustavo Thalmer M.; da Silva, Karen M.; Silva, Cassio P.; Rodrigues, Ana Clara B.; Oake, Jessy; Gehlen, Marcelo H.; Bohne, Cornelia; Quina, Frank H.

Photochemical & Photobiological Sciences (2019), 18 (7), 1750-1760CODEN: PPSHCB; ISSN:1474-905X. (Royal Society of Chemistry)

Flavylium cations serve as models for the chem. and photochem. reactivity of anthocyanins, the natural plant pigment responsible for many of the red, blue and purple colors of fruits and flowers. Likewise, pyranoflavylium cations serve as models of the fundamental chromophoric moiety of pyranoanthocyanins, mols. that can form from reactions of grape anthocyanins in red wines during their maturation. In the present work, hybrid pigments are prepd. by the adsorption of a series of five synthetic flavylium cations (FL) and five synthetic pyranoflavylium cations (PFL) on sepiolite clay (SEP). The FL are smaller in size than the PFL, but both can in principle fit into the tunnels and/or external grooves (with dimensions of 3.7 × 10.6 Å) of SEP. Measurements of the fluorescence quantum yields of the adsorbed dyes indicate that they are at least as fluorescent as in acidic acetonitrile soln., and in a few cases substantially more fluorescent. The observation of biexponential fluorescence decays is consistent with emission from dye mols. adsorbed at two distinct sites, presumably tunnels and grooves. These hybrid materials also have improved properties in terms of stability of the color in contact with pH 10 aq. soln. and resistance to thermal degrdn. of the dye. SEP thus appears to be a promising substrate for the development of highly fluorescent flavylium or pyranoflavylium cation-derived hybrid pigments with improved color and thermal stability.

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383

Li, S. ; Ding, J. ; Mu, B. ; Wang, X. ; Kang, Y. ; Wang, A. Acid/Base Reversible Allochroic Anthocyanin/Palygorskite Hybrid Pigments: Preparation, Stability and Potential Applications. Dyes Pigm. 2019, 171 , 107738, DOI: 10.1016/j.dyepig.2019.107738

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383

Acid/base reversible allochroic anthocyanin/palygorskite hybrid pigments: Preparation, stability and potential applications

Li, Shue; Ding, Junjie; Mu, Bin; Wang, Xiaowen; Kang, Yuru; Wang, Aiqin

Dyes and Pigments (2019), 171 (), 107738pp.CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The color of natural anthocyanin is sensitive to acid or base atm., and thus it may be used as an intelligent acid/base-responsive allochroic pigment. However, the instability of anthocyanin to external environments severely limits their relevant applications. In this study, the org./inorg. hybrid pigment is facilely prepd. by adsorption of anthocyanin extd. from fresh blueberry using palygorskite followed by a grinding process. The effect of grinding time on the thermal and the chem. stabilities of hybrid pigment was studied, and it is found that the grinding process can promote the diffusion of anthocyanin mols. into the external grooves of palygorskite, which favors the improvement of the stability of natural anthocyanin to external environments. In addn., the colors of the resulting hybrid pigments transform from pale pink to steel gray with the change of atm. from acid to base. The effect of the added amts. of hybrid pigments on mech. properties of sodium alginate films are investigated, and the results indicate that the incorporation of hybrid pigments obviously improve the tensile strength and elongation at break of sodium alginate films.

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384

Li, S. ; Mu, B. ; Wang, X. ; Kang, Y. ; Wang, A. A Comparative Study on Color Stability of Anthocyanin Hybrid Pigments Derived from 1d and 2d Clay Minerals. Materials 2019, 12 , 3287, DOI: 10.3390/ma12203287

[Crossref], [CAS], Google Scholar

384

A comparative study on color stability of anthocyanin hybrid pigments derived from 1D and 2D clay minerals

Li, Shue; Mu, Bin; Wang, Xiaowen; Kang, Yuru; Wang, Aiqin

Materials (2019), 12 (20), 3287CODEN: MATEG9; ISSN:1996-1944. (MDPI AG)

Anthocyanin extd. from the fresh blue berry fruits was loaded onto different clay minerals including one-dimensional tubular halloysite and fibrous sepiolite, and two-dimensional lamellar kaolinite and montmorillonite to fabricate reversible allochroic hybrid pigments. The effect of the possible interaction mechanism between anthocyanin and clay minerals on the color stability of hybrid pigments was investigated. Due to the difference in the structures and properties of clay minerals, natural anthocyanin was inclined to be absorbed on the surface and intercalated into the interlayer of 2:1 type layered montmorillonite, while it was mainly anchored on the surface of 1:1 type kaolinite and halloysite. By contrast, it was simultaneously loaded on the surface and confined into the nanochannels and/or grooves of 2:1 type chain-layered sepiolite. Interestingly, the resulting hybrid pigments presented good thermal stability and resistance to chem. reagents, as well as reversible gas-sensitive allochroic behavior in HCl or NH3 gases, esp. anthocyanin/sepiolite hybrid pigments due to the shielding effect of the well-defined nanochannels and grooves of sepiolite. Based on this color-change behavior, a simple pH test paper was also prepd. with obvious color change at different pH values by coating the filter paper with anthocyanin/sepiolite hybrid pigments.

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385

Lima, L. C. B. ; Silva, F. C. ; Silva-Filho, E. C. ; Fonseca, M. G. ; Zhuang, G. ; Jaber, M. Saponite-Anthocyanin Derivatives: The Role of Organoclays in Pigment Photostability. Appl. Clay Sci. 2020, 191 , 105604, DOI: 10.1016/j.clay.2020.105604

[Crossref], [CAS], Google Scholar

385

Saponite-anthocyanin derivatives: The role of organoclays in pigment photostability

Lima, Luciano C. B.; Silva, Fabricia C.; Silva-Filho, Edson C.; Fonseca, Maria G.; Zhuang, Guanzheng; Jaber, Maguy

Applied Clay Science (2020), 191 (), 105604CODEN: ACLSER; ISSN:0169-1317. (Elsevier B.V.)

Hybrid pigments based on organo-saponite (cetyltrimethyl ammonium bromide (CTAB-Sap) and a com. anthocyanin (ACN) dye, Crystal Red Grape, were prepd. The interactions between org. dye guest and hosts (including saponite and organo-saponite) were investigated by X-ray diffraction, transmission electron microscopy and Fourier transform IR spectroscopy. The pigments exhibit different colors function of their host-guest interactions. The blue color of organo-clay-anthocyanin indicates the stabilization of quinoidal base form of the dye. The hybrids have good stability against visible light irradn. and basic pH conditions. These dyed materials are environmentally friendly and can be promising candidates in different application fields.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnslertrw%253D&md5=db7b2a370c27d15ef8c72660b1ef584d

386

Zhu, F. Interactions between Cell Wall Polysaccharides and Polyphenols. Crit. Rev. Food Sci. Nutr. 2018, 58 , 1808– 1831, DOI: 10.1080/10408398.2017.1287659

[Crossref], [PubMed], [CAS], Google Scholar

386

Interactions between cell wall polysaccharides and polyphenols

Zhu, Fan

Critical Reviews in Food Science and Nutrition (2018), 58 (11), 1808-1831CODEN: CRFND6; ISSN:1040-8398. (Taylor & Francis, Inc.)

In plant-based food systems such as fruits, vegetables, and cereals, cell wall polysaccharides and polyphenols co-exist and commonly interact during processing and digestion. The noncovalent interactions between cell wall polysaccharides and polyphenols may greatly influence the physicochem. and nutritional properties of foods. The affinity of cell wall polysaccharides with polyphenols depends on both endogenous and exogenous factors. The endogenous factors include the structures, compns., and concns. of both polysaccharides and polyphenols, and the exogenous factors are the environmental conditions such as pH, temp., ionic strength, and the presence of other components (e.g., protein). Diverse methods used to directly characterize the interactions include NMR spectroscopy, size-exclusion chromatog., confocal microscopy, isothermal titrn. calorimetry, mol. dynamics simulation, and so on. The un-bound polyphenols are quantified by liq. chromatog. or spectrophotometry after dialysis or centrifugation. The adsorption of polyphenols by polysaccharides is mostly driven by hydrophobic interactions and hydrogen bonding, and can be described by various isothermal models such as Langmuir and Freundlich equations. Quality attributes of various food and beverage products (e.g., wine) can be significantly affected by polysaccharide-polyphenol interactions. Nutritionally, the interactions play an important role in the digestive tract of humans for the metab. of both polyphenols and polysaccharides.

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387

Fernandes, A. ; Bras, N. F. ; Mateus, N. ; de Freitas, V. Understanding the Molecular Mechanism of Anthocyanin Binding to Pectin. Langmuir 2014, 30 , 8516– 8527, DOI: 10.1021/la501879w

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387

Understanding the molecular mechanism of anthocyanin binding to pectin

Fernandes, Ana; Bras, Natercia F.; Mateus, Nuno; de Freitas, Victor

Langmuir (2014), 30 (28), 8516-8527CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)

The assocn. between anthocyanins and carbohydrates has drawn attention over the past few years and this interaction is of particularly importance in food chem. since these compds. are often found together in plants and foodstuffs. This work intended to bring insights on the interaction between ionic carbohydrates (pectin) and 2 anthocyanins [cyanidin 3-O-glucoside (I) and delphinidin 3-O-glucoside (II)]. The interaction between the flavylium cation and hemiketal anthocyanin forms was characterized by satn. transfer difference (STD) NMR spectroscopy and the resp. dissocn. const. (Kd) was obtained. This binding was also studied by mol. dynamics simulation. In the presence of the anthocyanin hemiketal form, a weak interaction between anthocyanins and pectin appeared to occur. A variation in the extent of this interaction was also noticed for the 2 anthocyanins with II bearing 3 OH groups, revealed to be a stronger binder to pectin (Kd = ∼180 μM for II and Kd = ∼250 μM for I). Expts. performed at acidic pH (flavylium cation) revealed a much stronger interaction (Kd = ∼2 μM). These exptl. results were also supported by theor. studies which also revealed a stronger interaction in the presence of the anthocyanin flavylium cation and also a stronger interaction between pectin and II than with I (for the hemiketal form).

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388

Fernandes, A. ; Oliveira, J. ; Fonseca, F. ; Ferreira-da-Silva, F. ; Mateus, N. ; Vincken, J. P. ; de Freitas, V. Molecular Binding between Anthocyanins and Pectic Polysaccharides - Unveiling the Role of Pectic Polysaccharides Structure. Food Hydrocolloids 2020, 102 , 105625, DOI: 10.1016/j.foodhyd.2019.105625

[Crossref], [CAS], Google Scholar

388

Molecular binding between anthocyanins and pectic polysaccharides - Unveiling the role of pectic polysaccharides structure

Fernandes, Ana; Oliveira, Joana; Fonseca, Fatima; Ferreira-da-Silva, Frederico; Mateus, Nuno; Vincken, Jean-Paul; de Freitas, Victor

Food Hydrocolloids (2020), 102 (), 105625CODEN: FOHYES; ISSN:0268-005X. (Elsevier Ltd.)

The interaction between cyanidin-3-O-glucoside and four citrus pectic fractions was investigated using a combined mol. approach, including isothermal titrn. calorimetry (ITC), magnetic nuclear resonance (NMR) and UV-Visible spectrophotometry. These pectic fractions differed on their type and degree of esterification (amidated (AHG 30%), low (HG 30%) and high Me esterified fractions (HG 70%)) and on the pattern of esterification (blockwise (HG-B 70%) vrs random (HG-R 70%)). The binding const. (Ka) and the assocd. thermodn. parameters detd. showed weak noncovalent interactions, particularly due to electrostatic interactions, hydrogen bonding and hydrophobic effect. The degree and the type of esterification of each pectic fractions had a significant effect on the binding consts. detd. by ITC and NMR expts. The binding consts. ranged from 102 to 104 M-1, with the highest Ka value obsd. for the interaction between cy3glc and low methylesterified fraction, followed by the amidated fraction. Pectic fractions with a higher degree of Me esterification, resulted on lower binding affinities, with these interactions being mostly driven by hydrophobic effect compared to enthalpy. The different binding affinities could be correlated with anthocyanins color impact, as a higher red color intensity could be obsd. for a cy3glc model soln. fortified with a low methylated fraction. However, this color improvement was not obsd. for amidated fraction, presumably due to charge repulsive forces, lowering the stability of the flavylium cation.

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389

Fernandes, A. ; Brandão, E. ; Raposo, F. ; Maricato, É. ; Oliveira, J. ; Mateus, N. ; Coimbra, M. A. ; de Freitas, V. Impact of Grape Pectic Polysaccharides on Anthocyanins Thermostability. Carbohydr. Polym. 2020, 239 , 116240, DOI: 10.1016/j.carbpol.2020.116240

[Crossref], [PubMed], [CAS], Google Scholar

389

Impact of grape pectic polysaccharides on anthocyanins thermostability

Fernandes, Ana; Brandao, Elsa; Raposo, Filomena; Maricato, Elia; Oliveira, Joana; Mateus, Nuno; Coimbra, Manuel A.; de Freitas, Victor

Carbohydrate Polymers (2020), 239 (), 116240CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

The impact of grape pectic polysaccharides on malvidin-3-O-β-D-glucoside thermostability was evaluated in model solns. Pectic polysaccharides richer in homogalacturonan domains, with less neutral sidechains (chelator fraction) showed higher binding with malvidin-3-O-β-D-glucoside, by 1H NMR (Ka=505 M-1). Binding affinity with water sol. ext. was estd. to be 10-fold lower, possibly due to the presence of neutral branched regions and more compacted structure, hampering the binding. Hydrophobic domains, such as rhamnogalacturonans-I domains in acid sol. polysaccharides, may participate in the formation of complexes with malvidin-3-O-β-D-glucoside. The thermostability of anthocyanin-polysaccharides complexes was evaluated at different temps., assessing anthocyanins degrdn. by HPLC-DAD. Polysaccharides showed to improve anthocyanin thermostability, with chelator and acid ext. having the highest impact at lowest temps. Electrostatic interactions, addnl. stabilized by hydrophobic effect contribute to the anthocyanin-polysaccharides binding and to the consequent thermostabilization. The protection provided by grape pectic polysaccharides foresees innovative anthocyanin food products with improved thermostability and color features.

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390

Buchweitz, M. ; Carle, R. ; Kammerer, D. R. Bathochromic and Stabilising Effects of Sugar Beet Pectin and an Isolated Pectic Fraction on Anthocyanins Exhibiting Pyrogallol and Catechol Moieties. Food Chem. 2012, 135 , 3010– 3019, DOI: 10.1016/j.foodchem.2012.06.101

[Crossref], [PubMed], [CAS], Google Scholar

390

Bathochromic and stabilising effects of sugar beet pectin and an isolated pectic fraction on anthocyanins exhibiting pyrogallol and catechol moieties

Buchweitz, M.; Carle, R.; Kammerer, D. R.

Food Chemistry (2012), 135 (4), 3010-3019CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The formation of anthocyanin-metal chelates, exhibiting intense blue colors was monitored over a period up to 10 wk. Evaluating normalized absorption spectra in the range of 580-700 nm and their proportion of the total area under the curve (AUC), provided information about the blue color hue, intensity and stability. Color stability in model solns. contg. com. sugar beet pectin or an isolated pectic polysaccharide fraction (PPF) therefrom, both being naturally enriched in aluminum and ferric ions, was assessed in a pH range of 3.6-7.0. The pectic structures stabilized anthocyanin-metal chelates, and thus blue colors by efficiently preventing complex pptn. Highest bathochromic shifts and most intense blue colors were obsd. in PPF model solns. contg. delphinidin-3-glucoside (Dpd-3-glc), exhibiting a pyrogallol moiety in the flavylium B-ring, compared to cyanidin- (Cyd-3-glc) and petunidin-3-glucoside (Pet-3-glc), both carrying a catechol substituted B-ring. Hue and intensity of the blue color at pH 5.0 were only insignificantly influenced by the buffer system except for citrate and phosphate buffers, which both annihilated anthocyanin-metal chelate formation. The blue colors faded following first order kinetics. Best stabilities as deduced from storage expts. performed at 20±2° in the dark were obsd. for Dpd-3-glc. In contrast, Cyd-3-glc displayed shortened half-life values, whereas blue Pet-3-glc chelates decompd. rapidly. These results demonstrate that the solubilization of anthocyanin-metal chelates by pectic structures is a promising option for developing water sol. natural blue food colorants.

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391

Jeong, D. ; Na, K. Chondroitin Sulfate Based Nanocomplex for Enhancing the Stability and Activity of Anthocyanin. Carbohydr. Polym. 2012, 90 , 507– 515, DOI: 10.1016/j.carbpol.2012.05.072

[Crossref], [PubMed], [CAS], Google Scholar

391

Chondroitin sulfate based nanocomplex for enhancing the stability and activity of anthocyanin

Jeong, Dooyong; Na, Kun

Carbohydrate Polymers (2012), 90 (1), 507-515CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

To improve the structural stability of the potent antioxidant anthocyanin (ATC), a nanocomplex was fabricated from intermol. stacking between chondroitin sulfate (CS) and ATC using a simple complexing method in water, without inputting high energy or an org. solvent. The physicochem. properties of the nanocomplex were evaluated at various feed wt. ratios of CS/ATC. The most stable nanocomplex was obtained at a CS/ATC wt. ratio of 10/1 (WR10). The ATC loading content and loading efficiency were 6.3 and 99%, resp. Its diam. was approx. 300 nm with unimodal size distribution. The intermol. stacking state of WR10 was maintained up to 1 μg/mL of ATC, whereas an intermol. stacking state formed by ATC alone was easily dissocd. below 16 μg/mL of ATC. The structural stability of ATC in WR10 was 8 times higher than that of free ATC at 37 °C. Moreover, the complex effectively protected the ATC degrdn. by hydroxyl mols. under high pH (above 9) conditions. Finally, cancer cell growth suppression activity was measured to det. the in vitro free radical scavenger ability of ATC. The WR10 strongly suppressed the Hela cell growth compared with ATC alone. Therefore, we conclude that the CS/ATC nanocomplex has a potential for use as a carrier for stable antioxidants or water-sol. drugs via intermol. stacking. These nanocomplexes would prove useful for applications in the food and pharmaceutical industries.

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392

Tan, C. ; B. Celli, G. ; Lee, M. ; Licker, J. ; Abbaspourrad, A. Polyelectrolyte Complex Inclusive Biohybrid Microgels for Tailoring Delivery of Copigmented Anthocyanins. Biomacromolecules 2018, 19 , 1517– 1527, DOI: 10.1021/acs.biomac.8b00352

[ACS Full Text ], [CAS], Google Scholar

392

Polyelectrolyte complex inclusive biohybrid microgels for tailoring delivery of copigmented anthocyanins

Tan, Chen; B. Celli, Giovana; Lee, Michelle; Licker, Jonathan; Abbaspourrad, Alireza

Biomacromolecules (2018), 19 (5), 1517-1527CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)

This study fabricated a novel biohybrid microgel contg. polysaccharide-based polyelectrolyte complexes (PECs) for anthocyanins. Herein, anthocyanins were encapsulated into PECs composed of chondroitin sulfate and chitosan, followed by incorporation into alginate microgels using emulsification/internal gelation method. We demonstrated that PECs incorporation strongly affected the properties of microgels, dependent on the polysaccharide concn. and pH in which they were fabricated. The dense internal network surrounded by an alginate shell was clearly visualized in cross-sectioned PECs-microgels. Stability studies carried out under varying ionic strength and pH conditions demonstrated the stimuli-responsiveness of the PECs-microgels. Addnl., the presence of PECs conferred microgels with high rigidity during freeze-drying and excellent reconstitution capacity upon rehydration. These observations were attributed to the modulation of electrostatic and hydrogen-bonding crosslinking between PECs and the alginate gel matrix and suggest the PECs inclusive microgels hold promise as delivery vehicles for the controlled release of hydrophilic bioactive compds.

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393

Klimaviciute, R. ; Navikaite, V. ; Jakstas, V. ; Ivanauskas, L. Complexes of Dextran Sulfate and Anthocyanins from Vaccinium Myrtillus: Formation and Stability. Carbohydr. Polym. 2015, 129 , 70– 78, DOI: 10.1016/j.carbpol.2015.04.038

[Crossref], [PubMed], [CAS], Google Scholar

393

Complexes of dextran sulfate and anthocyanins from Vaccinium myrtillus: Formation and stability

Klimaviciute, Rima; Navikaite, Vesta; Jakstas, Valdas; Ivanauskas, Liudas

Carbohydrate Polymers (2015), 129 (), 70-78CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

To improve the stability and antioxidant activity of anthocyanins (ATC), complexes of dextran sulfate (DESU) and ATC extd. from Vaccinium myrtillus were formed during electrostatic interaction between sulfo groups of DESU and cationic moieties of ATC. At the optimal wt. ratio DESU/ATC = 0.4 g/g, the amt. of ATC introduced into a complex depended on the total concn. of the reagents. About 1.7 g of ATC per g of DESU could be incorporated into a complex. The formation of DESU/ATC complexes was confirmed by HPLC and FT-IR spectroscopy. According to HPLC anal., the amt. of individual ATC incorporated into a complex varied from 73.7% in the case of malvidin-3-O-glucoside to 90.8% in the case of delphinidin-3-arabinoside.

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394

Tan, C. ; Celli, G. B. ; Abbaspourrad, A. Copigment-Polyelectrolyte Complexes (Pecs) Composite Systems for Anthocyanin Stabilization. Food Hydrocolloids 2018, 81 , 371– 379, DOI: 10.1016/j.foodhyd.2018.03.011

[Crossref], [CAS], Google Scholar

394

Copigment-polyelectrolyte complexes (PECs) composite systems for anthocyanin stabilization

Tan, Chen; Celli, Giovana B.; Abbaspourrad, Alireza

Food Hydrocolloids (2018), 81 (), 371-379CODEN: FOHYES; ISSN:0268-005X. (Elsevier Ltd.)

This study aimed to explore copigment-polyelectrolyte complexes (PECs) composite systems for simultaneous color intensification and stabilization of anthocyanins. The polysaccharide-based PECs consisting of chitosan and chondroitin sulfate were fabricated at different pHs (3.3, 4.0, and 5.0) and incorporated various copigments, including catechol (CAT), gallic acid (GA), gallic acid Et ester (GAEE), and (-)-epigallocatechin gallate (EGCG). We found that copigments could modulate anthocyanin loading into PECs and color quality of formulations, depending on the formulated pH and types of copigments. At pH 3.3 and 4.0, the incorporation of copigments simultaneously improved the red color and encapsulation efficiency of PECs, whereas these effects were not pronounced at pH 5.0. Stability assay demonstrated the synergistic effect of copigmentation and PECs encapsulation at pH 3.3 on protection of anthocyanin against nucleophilic attack of ascorbic acid. This phenomenon was attributed to the addnl. dense network created by hydrogen bonding between copigments and polysaccharides as well as the formation of hydrophobic environments inside PECs. The strongest copigmentation effect was obsd. for GAEE, followed by CAT, GA, and EGCG. However, the stabilizing effect of copigments was negligible or even opposite at pH 4.0 and 5.0. Our findings on pH- and copigment-dependent modulating effects should guide the design of copigment-PECs composite systems as carriers for natural colorants, such as anthocyanin, in nutraceuticals and functional foods.

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395

Tan, C. ; Celli, G. B. ; Selig, M. J. ; Abbaspourrad, A. Catechin Modulates the Copigmentation and Encapsulation of Anthocyanins in Polyelectrolyte Complexes (Pecs) for Natural Colorant Stabilization. Food Chem. 2018, 264 , 342– 349, DOI: 10.1016/j.foodchem.2018.05.018

[Crossref], [PubMed], [CAS], Google Scholar

395

Catechin modulates the copigmentation and encapsulation of anthocyanins in polyelectrolyte complexes (PECs) for natural colorant stabilization

Tan, Chen; Celli, Giovana B.; Selig, Michael Joseph; Abbaspourrad, Alireza

Food Chemistry (2018), 264 (), 342-349CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Our objective was to develop a robust system for anthocyanin-based color intensification, with high-encapsulation capacity and improved stability of the encapsulated natural colorant. Catechin was used to modulate the copigmentation and encapsulation of anthocyanins in counter-ionic polyelectrolyte complexes (PECs) composed of chondroitin sulfate and chitosan. Results showed that catechin copigmentation significantly intensified red color of formulations both with and without encapsulation in PECs and improved the anthocyanin encapsulation efficiency by forming addnl. dense network through hydrogen bonding. A series of stability assays revealed that anthocyanin stabilizing effect of system depended on the formulated pH and adding order of catechin. The strongest retaining capacity of anthocyanin was obsd. when catechin was copigmented with anthocyanin directly in PECs at pH 3.3, while the coated layer of catechin covered on PECs would be more effective at pH 4.0 and 5.0. Furthermore, we demonstrated that this delivery system works for anthocyanins from different sources.

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396

Araújo, P. ; Basílio, N. ; Fernandes, A. ; Mateus, N. ; de Freitas, V. ; Pina, F. ; Oliveira, J. Impact of Lignosulfonates on the Thermodynamic and Kinetic Parameters of Malvidin-3-O-Glucoside in Aqueous Solutions. J. Agric. Food Chem. 2018, 66 , 6382– 6387, DOI: 10.1021/acs.jafc.8b02273

[ACS Full Text ], [CAS], Google Scholar

396

Impact of Lignosulfonates on the Thermodynamic and Kinetic Parameters of Malvidin-3-O-glucoside in Aqueous Solutions

Araujo, Paula; Basilio, Nuno; Fernandes, Ana; Mateus, Nuno; de Freitas, Victor; Pina, Fernando; Oliveira, Joana

Journal of Agricultural and Food Chemistry (2018), 66 (25), 6382-6387CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The interaction of malvidin-3-O-glucoside (1) and a lignosulfonate was studied by UV-visible spectroscopy, and the results obtained showed the formation of a complex between the neg. charged lignosulfonate and the flavylium cation form (AH+) of this anthocyanin at pH 1. The thermodn. and kinetic parameters of 1 in the presence of a lignosulfonate were detd. by UV-visible spectroscopy and stopped-flow techniques. The main differences were obsd. in the flavylium cation (AH+)/quinoidal base (A) equil., the AH+ form being more stabilized than A (pKa1 = 4.4 ± 0.1) compared with 1 in the absence of the lignosulfonate (pKa1 = 3.9 ± 0.1). Furthermore, comparing the hydration (kh = 0.028 s-1) and dehydration (k-h = 40 M-1 s-1) processes of 1 in the presence of the lignosulfonate with the processes of 1 (kh = 0.12 s-1 and k-h = 35 M-1 s-1) show that the hydration process is slower while the dehydration process is practically unaffected in the presence of the lignosulfonate.

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397

Araújo, P. ; Basílio, N. ; Azevedo, J. ; Fernandes, A. ; Mateus, N. ; Pina, F. ; de Freitas, V. ; Oliveira, J. Colour Modulation of Blue Anthocyanin-Derivatives. Lignosulfonates as a Tool to Improve the Water Solubility of Natural Blue Dyes. Dyes Pigm. 2018, 153 , 150– 159, DOI: 10.1016/j.dyepig.2018.02.019

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397

Colour modulation of blue anthocyanin-derivatives. Lignosulfonates as a tool to improve the water solubility of natural blue dyes

Araujo, Paula; Basilio, Nuno; Azevedo, Joana; Fernandes, Ana; Mateus, Nuno; Pina, Fernando; de Freitas, Victor; Oliveira, Joana

Dyes and Pigments (2018), 153 (), 150-159CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

The impact of a lignosulfonate (calcium) (L) on the chromatic features of two anthocyanin-derived bluish dyes (portisin, P and pyranoanthocyanin dimer, PD) was evaluated in aq. solns. using UV-Visible spectroscopy. It was demonstrated that the interaction between each dye and this macromol. at pH 1 occurs by two mechanisms, assocn. and copigmentation that are dependent on L concn. For instance, at low concns. of L (up to 0.27 μM) it is obsd. the assocn. of dyes promoted by their complexation with lignin (different mols. of dye are bound to the same binding sites of L). At higher concns. of L (25 μM), the aggregation of dyes decreases and each mol. is bound to a different site of L resulting in the formation of a charge-transfer complex (copigmentation). Moreover, the titrn. of both dyes (P and PD) in the presence of L (19 μM) showed a strong stabilization of their pyranoflavylium cation forms revealed by the considerably higher pKa1 (6.6 ± 0.1 and 6.2 ± 0.1 for P and PD, resp.) in the presence of this macromol. when compared to the values obtained in the absence (pKa1 = 4.61 ± 0.03 and 4.93 ± 0.04). In addn., the water soly. of the dyes in the absence and presence of L was also evaluated by turbidimetry and the results showed that the water sol. lignosulfonate improved the soly. of the dyes over time.

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398

Chung, C. ; Rojanasasithara, T. ; Mutilangi, W. ; McClements, D. J. Stability Improvement of Natural Food Colors: Impact of Amino Acid and Peptide Addition on Anthocyanin Stability in Model Beverages. Food Chem. 2017, 218 , 277– 284, DOI: 10.1016/j.foodchem.2016.09.087

[Crossref], [PubMed], [CAS], Google Scholar

398

Stability improvement of natural food colors: Impact of amino acid and peptide addition on anthocyanin stability in model beverages

Chung, Cheryl; Rojanasasithara, Thananunt; Mutilangi, William; McClements, David Julian

Food Chemistry (2017), 218 (), 277-284CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Anthocyanins are prone to chem. degrdn. and color fading in the presence of vitamin C. The potential of three amino acids (L-phenylalanine, L-tyrosine, L-tryptophan) and a polypeptide (ε-poly-L-lysine) in prolonging the color stability of purple carrot anthocyanins (0.025%) in model beverages (0.05% L-ascorbic acid, citric acid, pH 3.0) stored at elevated temp. (40 °C/7 days) was examd. In the absence of amino acids or peptides, anthocyanin degraded at first-order reaction rate. Addn. of amino acids or peptide (0.1%) increased the color stability of anthocyanins, with the most significant improvement obsd. for L-tryptophan. The av. half-life of anthocyanin color increased from 2 days to 6 days with L-tryptophan addn. Fluorescence quenching measurements revealed that the L-tryptophan interacted with anthocyanins mainly through hydrogen bonding, although some hydrophobic interaction may also have been involved. Overall, this study suggests that amino acid or peptide addn. may prolong the color stability of anthocyanin in beverage products.

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399

Dangles, O. ; Brouillard, R. Poplyphenol Interactions - the Copigmentation Case - Thermodynamic Data from Temperature-Variation and Relaxation Kinetics-Medium Effect. Can. J. Chem. 1992, 70 , 2174– 2189, DOI: 10.1139/v92-273

[Crossref], [CAS], Google Scholar

399

Polyphenol interactions. The copigmentation case: thermodynamic data from temperature variation and relaxation kinetics. Medium effect

Dangles, Olivier; Brouillard, Raymond

Canadian Journal of Chemistry (1992), 70 (8), 2174-89CODEN: CJCHAG; ISSN:0008-4042.

Copigmentation of malvin with a series of naturally occurring colorless org. mols. has been investigated by UV-visible absorption. The temp.-dependence of the visible spectrum of the copigmented solns. yields the copigmentation enthalpy and entropy changes. Copigmentation appears to be clearly enthalpically driven (exothermic process with unfavorable entropy change) in the case of chlorogenic acid and (+)-catechin. Concerning caffeine and tryptophan, favorable entropy changes, probably arising from solvation effects, have been recorded. Similar expts. in water-ethanol binary solvents have shown pigmentation have been investigated as well. Relaxation kinetic measurements on the malvin-rutin system give striking evidence of the strong slowing down that a good copigment causes to the anthocyanin fading process (hydration). From the decrease in the apparent first-order rate const. of hydration on copigment addn., a general method for a quick detn. of the copigmentation stability consts. is proposed.

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400

Fasano, M. ; Curry, S. ; Terreno, E. ; Galliano, M. ; Fanali, G. ; Narciso, P. ; Notari, S. ; Ascenzi, P. The Extraordinary Ligand Binding Properties of Human Serum Albumin. IUBMB Life 2005, 57 , 787– 796, DOI: 10.1080/15216540500404093

[Crossref], [PubMed], [CAS], Google Scholar

400

The extraordinary ligand binding properties of human serum albumin

Fasano, Mauro; Curry, Stephen; Terreno, Enzo; Galliano, Monica; Fanali, Gabriella; Narciso, Pasquale; Notari, Stefania; Ascenzi, Paolo

IUBMB Life (2005), 57 (12), 787-796CODEN: IULIF8; ISSN:1521-6543. (Taylor & Francis Ltd.)

A review. Human serum albumin (HSA), the most prominent protein in plasma, binds different classes of ligands at multiple sites. HSA provides a depot for many compds., affects pharmacokinetics of many drugs, holds some ligands in a strained orientation by providing their metabolic modification, renders potential toxins harmless by transporting them to disposal sites, accounts for most of the antioxidant capacity of human serum, and acts as a NO carrier. The globular domain structural organization of monomeric HSA is at the root of its allosteric properties which are reminiscent of those of multimeric proteins. Here, structural, functional, biotechnol., and biomedical aspects of ligand binding to HSA are summarized.

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401

Abou-Zied, O. K. ; Al-Shihi, O. I. K. Characterization of Subdomain Iia Binding Site of Human Serum Albumin in Its Native, Unfolded, and Refolded States Using Small Molecular Probes. J. Am. Chem. Soc. 2008, 130 , 10793– 10801, DOI: 10.1021/ja8031289

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401

Characterization of Subdomain IIA Binding Site of Human Serum Albumin in its Native, Unfolded, and Refolded States Using Small Molecular Probes

Abou-Zied, Osama K.; Al-Shihi, Othman I. K.

Journal of the American Chemical Society (2008), 130 (32), 10793-10801CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)

Subdomain IIA binding site of human serum albumin (HSA) was characterized by examg. the change in HSA fluorescence in the native, unfolded, and refolded states. The study was carried out in the absence and presence of small mol. probes using steady-state and time-resolved fluorescence measurements. 2-Pyridone, 3-pyridone, and 4-pyridone bear similar mol. structures to those found in many drugs and are used here as probes. They are found to specifically bind in subdomain IIA and cause a redn. in the fluorescence intensity and lifetime of the Trp-214 residue in native HSA which is located in the same subdomain. The efficiency of energy transfer from Trp-214 fluorescence to the probes was found to depend on the degree of the spectral overlap between the donor's fluorescence and the acceptor's absorption. After probe binding in subdomain IIA, the distance between the donor and acceptor was calcd. using Forster theory. The calcd. quenching rate consts. and binding consts. were also shown to depend on the degree of spectral overlap. The results point to a static quenching mechanism operating in the complexes. Denaturation of HSA in the presence of guanidine hydrochloride (GdnHCl) starts at [GdnHCl] > 1.0 M and is complete at [GdnHCl] ≥ 6.0 M. Upon unfolding, two fluorescence peaks were obsd. One peak was assigned to the fluorescence of Trp-214 in a polar environment, and the other peak was assigned to tyrosine fluorescence. A redn. of the fluorescence intensity of the two peaks upon binding of the probes to the denatured HSA indicates that Tyr-263 in subdomain IIA is one of the tyrosine residues responsible for the second fluorescence peak. The results were confirmed by measuring the fluorescence spectra and lifetimes of denatured HSA at different excitation wavelengths, and of L-tryptophan and L-tyrosine free in buffer. The measured lifetimes of denatured HSA are typical of tryptophan in a polar environment and are slightly reduced upon probe binding. Diln. of the denatured HSA by buffer results in a partial refolding of subdomain IIA. This partial refolding is attributed to some swelling of the binding site caused by water. The swelling prevents a full recovery from the denatured state.

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402

Kanakis, C. D. ; Tarantilis, P. A. ; Polissiou, M. G. ; Diamantoglou, S. ; Tajmir-Riahi, H. A. Antioxidant Flavonoids Bind Human Serum Albumin. J. Mol. Struct. 2006, 798 , 69– 74, DOI: 10.1016/j.molstruc.2006.03.051

[Crossref], [CAS], Google Scholar

402

Antioxidant flavonoids bind human serum albumin

Kanakis, C. D.; Tarantilis, P. A.; Polissiou, M. G.; Diamantoglou, S.; Tajmir-Riahi, H. A.

Journal of Molecular Structure (2006), 798 (1-3), 69-74CODEN: JMOSB4; ISSN:0022-2860. (Elsevier B.V.)

Human serum albumin (HSA) is a principal extracellular protein with a high concn. in blood plasma and carrier for many drugs to different mol. targets. Flavonoids are powerful antioxidants and prevent DNA damage. The antioxidative protections are related to their binding modes to DNA duplex and complexation with free radicals in vivo. However, flavonoids are known to inhibit the activities of several enzymes such as calcium phospholipid-dependent protein kinase, tyrosine protein kinase from rat lung, phosphorylase kinase, phosphatidylinositol 3-kinase and DNA topoisomerases that exhibit the importance of flavonoid-protein interaction. This study was designed to examine the interaction of human serum albumin (HSA) with quercetin (que), kaempferol (kae) and delphinidin (del) in aq. soln. at physiol. conditions, using const. protein concn. of 0.25 mM (final) and various drug contents of 1 μM-1 mM. FTIR and UV-vis spectroscopic methods were used to det. the polyphenolic binding mode, the binding const. and the effects of flavonoid complexation on protein secondary structure. The spectroscopic results showed that flavonoids are located along the polypeptide chains through H-bonding interactions with overall affinity const. of Kque = 1.4 × 104 M-1, Kkae = 2.6 × 105 M-1 and Kdel = 4.71 × 105 M-1. The protein secondary structure showed no alterations at low pigment concn. (1 μM), whereas at high flavonoid content (1 mM), major redn. of α-helix from 55% (free HSA) to 42-46% and increase of β-sheet from 15% (free HSA) to 17-19% and β-anti from 7% (free HSA) to 10-20% occurred in the flavonoid-HSA adducts. The major redn. of HSA α-helix is indicative of a partial protein unfolding upon flavonoid interaction.

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403

Cahyana, Y. ; Gordon, M. H. Interaction of Anthocyanins with Human Serum Albumin: Influence of Ph and Chemical Structure on Binding. Food Chem. 2013, 141 , 2278– 2285, DOI: 10.1016/j.foodchem.2013.05.026

[Crossref], [PubMed], [CAS], Google Scholar

403

Interaction of anthocyanins with human serum albumin: Influence of pH and chemical structure on binding

Cahyana, Yana; Gordon, Michael H.

Food Chemistry (2013), 141 (3), 2278-2285CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The affinity of anthocyanins for human serum albumin (HSA) was detd. by a fluorescence quenching method. The effects of pH and structure of anthocyanins on the binding consts. were studied. The consts. for binding of anthocyanins to HSA ranged from 1.08 × 105 to 13.2 × 105 M-1. A hydrophobic effect at acidic pH was shown by the relatively high pos. entropy values under the conditions studied. Electrostatic interactions, including hydrogen bonding, contributed to the binding at pH 7.4. The effect of structure of anthocyanins on the affinity was pH-dependent, particularly the effect of addnl. hydroxyl substituents. Hydroxyl substituents and glycosylation of anthocyanins decreased the affinity for binding to HSA at lower pH (esp. pH 4), but increased the strength of binding at pH 7.4. In contrast, methylation of a hydroxyl group enhanced the binding at acidic pH, while this substitution reduced the strength of binding at pH 7.4. This paper shows that changes in anthocyanin structure or redns. in pH, which may occur in the region of inflammatory sites, have an effect on the binding of anthocyanins to HSA.

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404

Matei, I. ; Hillebrand, M. Interaction of Kaempferol with Human Serum Albumin: A Fluorescence and Circular Dichroism Study. J. Pharm. Biomed. Anal. 2010, 51 , 768– 773, DOI: 10.1016/j.jpba.2009.09.037

[Crossref], [PubMed], [CAS], Google Scholar

404

Interaction of kaempferol with human serum albumin: A fluorescence and circular dichroism study

Matei, Iulia; Hillebrand, Mihaela

Journal of Pharmaceutical and Biomedical Analysis (2010), 51 (3), 768-773CODEN: JPBADA; ISSN:0731-7085. (Elsevier B.V.)

The interaction of kaempferol (kaemp), a natural flavonoid to which antioxidative, anti-inflammatory and cardioprotective biol. activities have been attributed, with human serum albumin (HSA), the main in vivo transporter of exogenous substances, was investigated by steady-state, synchronous fluorescence and CD spectroscopies. The binding const., K, and no. of binding sites, n, were computed using literature models that showed satisfactory agreement and revealed a strong interaction (K ∼ 3.5×105 M-1, n ∼ 1). The binding process was investigated at temps. in the range 298-313 K, allowing for the evaluation of the thermodn. parameters, which indicate the occurrence of hydrogen bonding interactions. The distance between kaemp and the tryptophan residue of HSA was estd. at 2.7 nm using Foerster's theory of nonradiative resonance energy transfer. Using CD we evidenced some degree of HSA defolding upon binding.

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405

Sengupta, B. ; Sengupta, P. K. The Interaction of Quercetin with Human Serum Albumin: A Fluorescence Spectroscopic Study. Biochem. Biophys. Res. Commun. 2002, 299 , 400– 403, DOI: 10.1016/S0006-291X(02)02667-0

[Crossref], [PubMed], [CAS], Google Scholar

405

The interaction of quercetin with human serum albumin: a fluorescence spectroscopic study

Sengupta, Bidisa; Sengupta, Pradeep K.

Biochemical and Biophysical Research Communications (2002), 299 (3), 400-403CODEN: BBRCA9; ISSN:0006-291X. (Elsevier Science)

Quercetin (3,3',4',5,7-pentahydroxyflavone), a ubiquitous, bioactive plant flavonoid, is known to possess anti-cancer, anti-tumor, and other important therapeutic activities of significant potency and low systemic toxicity. In this communication, we report for the first time a study on the interactions of quercetin with the plasma protein human serum albumin (HSA), exploiting the intrinsic fluorescence emission properties of quercetin as a probe. Quercetin is weakly fluorescent in aq. buffer medium, with an emission max. at ≈538 nm. Binding of quercetin with HSA leads to dramatic enhancement in the fluorescence emission intensity and anisotropy (r), along with significant changes in the fluorescence excitation and emission profiles. The excitation spectrum suggests occurrence of efficient Forster type resonance energy transfer (FRET) from the single tryptophan-214 residue of HSA to the protein bound quercetin. The emission, excitation, and anisotropy (r=0.18 at [HSA]=30 μM) data (using the native protein) along with emission studies of quercetin using partially denatured HSA (by 8 M urea) indicate that the quercetin mols. bind at a motionally restricted site near tryptophan-214 in the interdomain cleft region of HSA. Furthermore, the binding const. (K=1.9×105 M-1) and Gibbs free energy change (ΔG0=-30.12 kJ/mol) for quercetin-HSA interaction have been calcd. from the relevant anisotropy data. Implications of these results are examd., particularly in relation to prospective applications in biomedical research.

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406

Tang, L. ; Zuo, H. ; Shu, L. Comparison of the Interaction between Three Anthocyanins and Human Serum Albumins by Spectroscopy. J. Lumin. 2014, 153 , 54– 63, DOI: 10.1016/j.jlumin.2014.03.004

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406

Comparison of the interaction between three anthocyanins and human serum albumins by spectroscopy

Tang, Lin; Zuo, Huijun; Shu, Li

Journal of Luminescence (2014), 153 (), 54-63CODEN: JLUMA8; ISSN:0022-2313. (Elsevier B.V.)

Anthocyanin is an important kind of water-sol. pigment existing widely in plants, and has various health benefits to human body. The no. and location of the hydroxyl groups of the parent nucleus of Anthocyanins have significant effects on their activities. This research employed different spectroscopic methods (i.e. fluorescence spectroscopy, UV-vis absorbance, three-dimensional fluorescence spectra and CD (CD)) to investigate the mutual interactions between three differently substituted B-ring hydroxyl groups (Pelargonidin-3-O-glucoside, P3G; Cyanidin-3-O-glucoside, C3G and Delphinidin-3-O-glucoside, D3G) and human serum albumin (HSA) under physiol. pH conditions. The calcd. thermodn. parameters and the spectrum showed that P3G, C3G and D3G could result in quenching of the intrinsic fluorescence. The comparison result of the strength of comprehensive binding parameter Y (i.e. Y=lg( Ka×E×n/r)), which was used to reflect the extent of interaction of Anthocyanin-HSA system, was YD3G>YC3G>YP3G. Moreover, the secondary structure of HSA was changed in the presence of P3G/C3G/D3G. The α-helix percentage of P3G-HSA increased while that of C3G/D3G-HSA decreased. Overall, these results showed that the no. of B-ring -OH in each mol. played an important role in the interaction of these anthocyanins with HSA.

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407

Al Bittar, S. ; Mora, N. ; Loonis, M. ; Dangles, O. Chemically Synthesized Glycosides of Hydroxylated Flavylium Ions as Suitable Models of Anthocyanins: Binding to Iron Ions and Human Serum Albumin, Antioxidant Activity in Model Gastric Conditions. Molecules 2014, 19 , 20709– 20730, DOI: 10.3390/molecules191220709

[Crossref], [PubMed], [CAS], Google Scholar

407

Chemically synthesized glycosides of hydroxylated flavylium ions as suitable models of anthocyanins: binding to iron ions and human serum albumin, antioxidant activity in model gastric conditions

Al Bittar, Sheiraz; Mora, Nathalie; Loonis, Michele; Dangles, Olivier

Molecules (2014), 19 (12), 20709-20730, 22 pp.CODEN: MOLEFW; ISSN:1420-3049. (MDPI AG)

Polyhydroxylated flavylium ions, such as 3',4',7-trihydroxyflavylium chloride (P1) and its more water-sol. 7-O-β-d-glucopyranoside (P2), are readily accessible by chem. synthesis and suitable models of natural anthocyanins in terms of color and species distribution in aq. soln. Owing to their catechol B-ring, they rapidly bind FeIII, weakly interact with FeII and promote its autoxidn. to FeIII. Both pigments inhibit heme-induced lipid peroxidn. in mildly acidic conditions (a model of postprandial oxidative stress in the stomach), the colorless (chalcone) forms being more potent than the colored forms. Finally, P1 and P2 are moderate ligands of human serum albumin (HSA), their likely carrier in the blood circulation, with chalcones having a higher affinity for HSA than the corresponding colored forms.

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408

Tang, L. ; Li, S. ; Bi, H. ; Gao, X. Interaction of Cyanidin-3-O-Glucoside with Three Proteins. Food Chem. 2016, 196 , 550– 559, DOI: 10.1016/j.foodchem.2015.09.089

[Crossref], [PubMed], [CAS], Google Scholar

408

Interaction of cyanidin-3-O-glucoside with three proteins

Tang, Lin; Li, Shu; Bi, Hongna; Gao, Xin

Food Chemistry (2016), 196 (), 550-559CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

We studied the binding of cyanidin-3-O-glucoside (C3G) with bovine serum albumin (BSA), Hb (Hb) and myoglobin (Mb), using multi-spectral techniques and mol. modeling. Fluorescence and time-resolved fluorescence studies suggested that C3G quenched BSA, Hb or Mb fluorescence in a static mode with binding consts. of 4.159, 0.695 and 1.545 × 104 L mol-1 at 308 K, resp. The thermodn. parameters represented hydrogen bonds and van der Waals forces dominated the binding. Furthermore, CD, UV-vis, and three-dimensional fluorescence spectra results indicated the secondary structures of BSA, Hb and Mb were partially destroyed by C3G with the α-helix percentage of C3G-Hb and C3G-Mb decreased while that of C3G-BSA was increased. UV-vis spectral results showed these binding interactions partially affected the heme bands of Hb and Mb. In addn., mol. modeling anal. supported the exptl. results well. The calcd. results of equil. fraction showed that the concn. of free C3G in plasma was high enough to be stored and transported from the circulatory system to reach their target sites to provide their therapeutic effects.

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409

Cheng, J. ; Liu, J.-H. ; Prasanna, G. ; Jing, P. Spectrofluorimetric and Molecular Docking Studies on the Interaction of Cyanidin-3-O-Glucoside with Whey Protein, Β-Lactoglobulin. Int. J. Biol. Macromol. 2017, 105 , 965– 972, DOI: 10.1016/j.ijbiomac.2017.07.119

[Crossref], [PubMed], [CAS], Google Scholar

409

Spectrofluorimetric and molecular docking studies on the interaction of cyanidin-3-O-glucoside with whey protein, β-lactoglobulin

Cheng, Jing; Liu, Jian-Hua; Prasanna, Govindarajan; Jing, Pu

International Journal of Biological Macromolecules (2017), 105 (Part_1), 965-972CODEN: IJBMDR; ISSN:0141-8130. (Elsevier B.V.)

The interaction of β-Lactoglobulin (β-Lg) with cyanidin-3-O-glucoside (C3G) was characterized using fluorescence, CD spectroscopy, and docking studies under physiol. conditions. Fluorescence studies showed that β-Lg has a strong binding affinity for C3G via hydrophobic interaction with the binding const., Ka, of 3.14 × 104 M-1 at 298 K. The secondary structure of β-Lg displayed an increase in the major structure of β-sheet upon binding with C3G, whereas a decrease in the minor structure of α-helix was also obsd. In addn., evidenced by near UV-CD, the interaction also disrupted the environments of Trp residues. The mol. docking results illustrated that both hydrogen bonding and the hydrophobic interaction are involved as an acting force during the binding process. These results may contribute to a better understanding over the enhanced physicochem. proprieties of anthocyanins due to the complexation with milk proteins.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht1KhsLzI&md5=c09212594012ac5256ae7d24353fc049

410

He, Z. ; Zhu, H. ; Xu, M. ; Zeng, M. ; Qin, F. ; Chen, J. Complexation of Bovine Β-Lactoglobulin with Malvidin-3-O-Glucoside and Its Effect on the Stability of Grape Skin Anthocyanin Extracts. Food Chem. 2016, 209 , 234– 240, DOI: 10.1016/j.foodchem.2016.04.048

[Crossref], [PubMed], [CAS], Google Scholar

410

Complexation of bovine β-lactoglobulin with malvidin-3-O-glucoside and its effect on the stability of grape skin anthocyanin extracts

He, Zhiyong; Zhu, Haidong; Xu, Mingzhu; Zeng, Maomao; Qin, Fang; Chen, Jie

Food Chemistry (2016), 209 (), 234-240CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The binding interaction between bovine β-lactoglobulin and malvidin-3-O-glucoside (MG), the major anthocyanin in grape skin anthocyanin exts. (GSAE), was studied at pH 6.3 using fluorescence, Fourier transform IR and CD spectroscopy. The binding const. (KS), binding force and effect of the interaction on the β-lactoglobulin conformation and GSAE stability were investigated. The results indicated that β-lactoglobulin complexed with MG mainly via hydrophobic interaction with KS of 0.67 × 103 M-1 at 297 K. The secondary structure of β-lactoglobulin was changed by MG binding, with a decrease in α-helix, turn and random coil and an increase in β-sheet. Bovine whey protein effectively prevented the color fading and degrdn. of anthocyanin in the GSAE soln. during the thermal treatment (80 °C/2 h), H2O2 oxidn. (0.005% H2O2/1 h) and photo illumination (5000 lx/5 d). The whey protein-anthocyanin complexation appeared to have a pos. effect on the thermal, oxidn. and photo stability of GSAE.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xms1Sgtr8%253D&md5=cf7f13149621da33e57e742f816263cc

411

Xu, J. ; Hao, M. ; Sun, Q. ; Tang, L. Comparative Studies of Interaction of Β-Lactoglobulin with Three Polyphenols. Int. J. Biol. Macromol. 2019, 136 , 804– 812, DOI: 10.1016/j.ijbiomac.2019.06.053

[Crossref], [PubMed], [CAS], Google Scholar

411

Comparative studies of interaction of β-lactoglobulin with three polyphenols

Xu, Jinhui; Hao, Minghao; Sun, Qifan; Tang, Lin

International Journal of Biological Macromolecules (2019), 136 (), 804-812CODEN: IJBMDR; ISSN:0141-8130. (Elsevier B.V.)

To investigate the interaction mechanism between bovine protein β-lactoglobulin (β-LG) and theaflavin (TA), chlorogenic acid (CA) and delphinidin-3-O-glucoside (D3G), multi-spectrometry anal. methods and mol. modeling were applied. Fluorescence expts. proved that polyphenols strongly quenched the intrinsic fluorescence of β-LG mainly through static quenching and the main interaction force was hydrophobic interaction. Moreover, Fourier transform IR (FTIR) and CD (CD) indicated that polyphenols changed β-LG secondary and tertiary structure. ELISA and mol. modeling study manifested that complex of β-LG with polyphenols could significantly reduce the IgE-binding capacity of β-LG due to the polyphenol binding site directly obscures the IgE linear epitopes. In conclusion, polyphenols had impact on the structure and potential functionality of β-LG, which would be valuable in dairy processing industry and food nutrition security.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1GitrnL&md5=be306ea181c9a20c66d28c513e55faed

412

He, Z. ; Xu, M. ; Zeng, M. ; Qin, F. ; Chen, J. Interactions of Milk Α- and Β-Casein with Malvidin-3-O-Glucoside and Their Effects on the Stability of Grape Skin Anthocyanin Extracts. Food Chem. 2016, 199 , 314– 322, DOI: 10.1016/j.foodchem.2015.12.035

[Crossref], [PubMed], [CAS], Google Scholar

412

Interactions of milk α- and β-casein with malvidin-3-O-glucoside and their effects on the stability of grape skin anthocyanin extracts

He, Zhiyong; Xu, Mingzhu; Zeng, Maomao; Qin, Fang; Chen, Jie

Food Chemistry (2016), 199 (), 314-322CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The interactions of α- and β-casein with malvidin-3-O-glucoside (MG), the major anthocyanin in grape skin anthocyanin exts. (GSAE), were examd. at pH 6.3 by fluorescence, fourier transform IR (FTIR) and CD (CD) spectroscopy. The binding const. (KS), binding force and effects of the interactions on the caseins conformation and GSAE stability were investigated. The results showed that α- and β-casein bound with MG via hydrophilic (van der Waals forces or hydrogen bonding) and hydrophobic interactions, resp. α-Casein had a slightly stronger binding affinity toward MG than β-casein, with resp. KS values of 0.51 × 103 M-1 and 0.46 × 103 M-1 at 297 K. The secondary structures of α- and β-casein were changed by MG binding, with a decrease in α-helix and an increase in turn for α-casein and no change in α-helix and a decrease in turn for β-casein. The casein-anthocyanin interaction appeared to have a pos. effect on the thermal, oxidn. and photo stability of GSAE.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVSrt77N&md5=6816e421986f79dd736e80fa8b8c2805

413

Casanova, F. ; Chapeau, A.-L. ; Hamon, P. ; de Carvalho, A. F. ; Croguennec, T. ; Bouhallab, S. Ph- and Ionic Strength-Dependent Interaction between Cyanidin-3-O-Glucoside and Sodium Caseinate. Food Chem. 2018, 267 , 52– 59, DOI: 10.1016/j.foodchem.2017.06.081

[Crossref], [PubMed], [CAS], Google Scholar

413

pH- and ionic strength-dependent interaction between cyanidin-3-O-glucoside and sodium caseinate

Casanova, Federico; Chapeau, Anne-Laure; Hamon, Pascaline; de Carvalho, Antonio F.; Croguennec, Thomas; Bouhallab, Said

Food Chemistry (2018), 267 (), 52-59CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

Understanding the mechanism of interaction between food proteins and bioactives constitutes the preliminary step to design food grade nanocarriers. We investigated the interaction between cyanidin-3-O-glucoside (C3G), and 20 nm-sized sodium caseinate nanoparticles (NaCas) at pH 7 and pH 2 by fluorescence spectroscopy and dynamic light scattering. The characterization of the C3G-NaCas interaction indicated that the fluorescence quenching mechanism was predominantly static. C3G interacted with two sets of binding sites with assocn. consts. Ka of 106 and 105 M-1. Electrostatic interactions dominated at pH 7, while hydrophobic effects were the main force at pH 2. Interestingly, the two sets of binding sites were discriminated by ionic strength at pH 7. The binding of C3G slightly modified the av. diam. of NaCas nanoparticles without alteration of its surface charge suggesting a complexation of C3G mols. in the internal casein structure. Thus, NaCas constitutes a putative nanocarrier for anthocyanins in new functional foods.

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414

Pitkowski, A. ; Nicolai, T. ; Durand, D. Scattering and Turbidity Study of the Dissociation of Casein by Calcium Chelation. Biomacromolecules 2008, 9 , 369– 375, DOI: 10.1021/bm7006899

[ACS Full Text ], [CAS], Google Scholar

414

Scattering and Turbidity Study of the Dissociation of Casein by Calcium Chelation

Pitkowski, Anne; Nicolai, Taco; Durand, Dominique

Biomacromolecules (2008), 9 (1), 369-375CODEN: BOMAF6; ISSN:1525-7797. (American Chemical Society)

The dissocn. of casein was studied after addn. of polyphosphate that leads to calcium chelation, using light and x-ray scattering and turbidimetry. It is shown that the dissocn. is a cooperative process; i.e., a casein complex is either completely dissocd. or remains largely intact. A systematic study was done of the dependence of the rate and extent of dissocn. on the polyphosphate concn. and was found to be detd. by the ratio between casein and polyphosphate. The structures of the casein complex and the small micellar particles formed after dissocn. were compared. Addnl. expts. with a different chelatant (EDTA) gave similar results.

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415

Soares, S. ; Kohl, S. ; Thalmann, S. ; Mateus, N. ; Meyerhof, W. ; De Freitas, V. Different Phenolic Compounds Activate Distinct Human Bitter Taste Receptors. J. Agric. Food Chem. 2013, 61 , 1525– 1533, DOI: 10.1021/jf304198k

[ACS Full Text ], [CAS], Google Scholar

415

Different phenolic compounds activate distinct human bitter taste receptors

Soares, Susana; Kohl, Susann; Thalmann, Sophie; Mateus, Nuno; Meyerhof, Wolfgang; De Freitas, Victor

Journal of Agricultural and Food Chemistry (2013), 61 (7), 1525-1533CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Bitterness is a major sensory attribute of several common foods and beverages rich in polyphenol compds. These compds. are reported as very important for health as chemopreventive compds., but they are also known to taste bitter. In this work, the activation of the human bitter taste receptors, TAS2Rs, by six polyphenol compds. was analyzed. The compds. chosen are present in a wide range of plant-derived foods and beverages, namely, red wine, beer, tea, and chocolate. Pentagalloylglucose (PGG) is a hydrolyzable tannin, (-)-epicatechin is a precursor of condensed tannins, procyanidin dimer B3 and trimer C2 belong to the condensed tannins, and malvidin-3-glucoside and cyanidin-3-glucoside are anthocyanins. The results show that the different compds. activate different combinations of the ∼25 TAS2Rs. (-)-Epicatechin activated three receptors, TAS2R4, TAS2R5, and TAS2R39, whereas only two receptors, TAS2R5 and TAS2R39, responded to PGG. In contrast, malvidin-3-glucoside and procyanidin trimer stimulated only one receptor, TAS2R7 and TAS2R5, resp. Notably, tannins are the first natural agonists found for TAS2R5 that display high potency only toward this receptor. The catechol and/or galloyl groups appear to be important structural determinants that mediate the interaction of these polyphenolic compds. with TAS2R5. Overall, the EC50 values obtained for the different compds. vary 100-fold, with the lowest values for PGG and malvidin-3-glucoside compds., suggesting that they could be significant polyphenols responsible for the bitterness of fruits, vegetables, and derived products even if they are present in very low concns.

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416

Ferrer-Gallego, R. ; Soares, S. ; Mateus, N. ; Rivas-Gonzalo, J. ; Escribano-Bailón, M. T. ; Freitas, V. d. New Anthocyanin–Human Salivary Protein Complexes. Langmuir 2015, 31 , 8392– 8401, DOI: 10.1021/acs.langmuir.5b01122

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416

New Anthocyanin-Human Salivary Protein Complexes

Ferrer-Gallego, Raul; Soares, Susana; Mateus, Nuno; Rivas-Gonzalo, Julian; Escribano-Bailon, M. Teresa; Freitas, Victor de

Langmuir (2015), 31 (30), 8392-8401CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)

The interaction between phenolic compds. and salivary proteins is considered the basis of the poorly understood phenomenon of astringency. Furthermore, this interaction is an important factor in relation to their bioavailability. In this work, interactions between anthocyanin and human salivary protein fraction were studied by mass spectrometry (MALDI-TOF-MS and FIA-ESI-MS) and satn.-transfer difference (STD) NMR spectroscopy. Anthocyanins were able to interact with saliva proteins. The dissocn. const. (KD) between malvidin 3-glucoside and salivary proline-rich proteins was 1.92 mM for the hemiketal form (pH 3.4) and 1.83 mM for the flavylium cation (pH 1.0). New sol. complexes between these salivary proteins and malvidin 3-glucoside were identified for the first time.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFGitL%252FF&md5=d53f96333e3d6dbe4dae355101f5bdd0

417

Soares, S. ; Santos Silva, M. ; García-Estévez, I. ; Brandão, E. ; Fonseca, F. ; Ferreira-da-Silva, F. ; Teresa Escribano-Bailón, M. ; Mateus, N. ; de Freitas, V. Effect of Malvidin-3-Glucoside and Epicatechin Interaction on Their Ability to Interact with Salivary Proline-Rich Proteins. Food Chem. 2019, 276 , 33– 42, DOI: 10.1016/j.foodchem.2018.09.167

[Crossref], [PubMed], [CAS], Google Scholar

417

Effect of malvidin-3-glucoside and epicatechin interaction on their ability to interact with salivary proline-rich proteins

Soares, Susana; Santos Silva, Mafalda; Garcia-Estevez, Ignacio; Brandao, Elsa; Fonseca, Fatima; Ferreira-da-Silva, Frederico; Teresa Escribano-Bailon, M.; Mateus, Nuno; de Freitas, Victor

Food Chemistry (2019), 276 (), 33-42CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

At red wine pH, malvidin-3-glucoside (mv-3-glc), the major anthocyanin of red wine, is expected to be present mainly in its non-colored hemiketal form. However, due to copigmentation with flavanols (e.g. epicatechin), the stabilization of the colored forms of mv-3-glc occurs. Some flavanols have been linked to astringency, due to their ability to interact/ppt. salivary proteins, namely proline-rich proteins (PRPs). So, a major question is if this copigmentation interaction could affect the ability of flavanols to interact with SP. To answer this, the effect of the interaction between mv-3-glc and epicatechin with basic and acidic PRPs, was investigated by satn.-tranfer difference (STD)-NMR and isothermal titrn. calorimetry (ITC). The most relevant result was that epicatechin:mv-3-glc mixt. presents a synergic effect toward the interaction with both PRPs when compared to individual polyphenols. Furthermore, was obsd. that epicatechin interaction was driven by hydrophobic and hydrophilic interactions while mv-3-glc interaction was driven by electrostatic interactions.

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418

Paissoni, M. A. ; Waffo-Teguo, P. ; Ma, W. ; Jourdes, M. ; Rolle, L. ; Teissedre, P. L. Chemical and Sensorial Investigation of in-Mouth Sensory Properties of Grape Anthocyanins. Sci. Rep. 2018, 8 , 17098, DOI: 10.1038/s41598-018-35355-x

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418

Chemical and sensorial investigation of in-mouth sensory properties of grape anthocyanins

Paissoni M A; Waffo-Teguo P; Ma W; Jourdes M; Teissedre P -L; Paissoni M A; Waffo-Teguo P; Ma W; Jourdes M; Teissedre P -L; Paissoni M A; Rolle L; Ma W

Scientific reports (2018), 8 (1), 17098 ISSN:.

Anthocyanins are water-soluble pigments found in the cell vacuoles of fruits and flowers, performing several roles from insects attraction to stress protection. Their antioxidant activity contributes to human health, and consuming plant-derived products provides their higher source in the diet. Although their colour and nutritional features, their contribution to sensory properties of foods has not been widely investigated. In wine, preferences are connected with sensory attributes of colour, aroma, taste, and mouthfeel. In this study, grape anthocyanin extracts (TAE) were fractionated using centrifugal partition chromatography (CPC) and preparative HPLC in three fractions, i.e glucoside (GF), acetylated (AF) and cinnamoylated (CF) anthocyanins. Sensory properties were investigated by chemical analysis, as reactivity towards bovin serum albumin (BSA) and salivary proteins, and in tasting sessions to assess anthocyanins best estimated thresholds (BET) in wine-like solution. Anthocyanins reacted with both BSA and salivary proteins, but to different extents, because higher interaction between salivary proteins and anthocyanins were found. Cinnamoylated anthocyanins are the most reactive to salivary proteins. Tasting sessions suggested an involvement of anthocyanins as in-mouth contributors in wine, since their BETs were 255, 297, 68, and 58 mg/L for TAE, GF, AF, and CF, respectively, and the descriptors reported were astringency and bitterness.

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419

García-Estévez, I. ; Cruz, L. ; Oliveira, J. ; Mateus, N. ; de Freitas, V. ; Soares, S. First Evidences of Interaction between Pyranoanthocyanins and Salivary Proline-Rich Proteins. Food Chem. 2017, 228 , 574– 581, DOI: 10.1016/j.foodchem.2017.02.030

[Crossref], [PubMed], [CAS], Google Scholar

419

First evidences of interaction between pyranoanthocyanins and salivary proline-rich proteins

Garcia-Estevez, Ignacio; Cruz, Luis; Oliveira, Joana; Mateus, Nuno; de Freitas, Victor; Soares, Susana

Food Chemistry (2017), 228 (), 574-581CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

The contribution of other classes of polyphenol compds. besides tannins to the overall perception of astringency is still poorly understood. So, this work aimed to study the interaction between a family of salivary proline-rich proteins (aPRPs) and representative pyranoanthocyanins in red wines [pyranomalvidin-3-glucoside (vitisin B), pyranomalvidin-3-glucoside-catechol, and pyranomalvidin-3-glucoside-epicatechin] using satn. transfer difference-NMR and MALDI-TOF. For vitisin B KD was of 1.74 mM; for pyranomalvidin-3-glucoside-catechol was 1.17 mM and for pyranomalvidin-3-glucoside-epicatechin it was 0.87 mM. The presence of the flavanol structural unit in the pyranoanthocyanins led to an increase in their interaction with aPRPs. Further, it is also interesting that the values obtained were in the range of KD obtained previously reported for the interaction between the human saliva proline-rich peptides (IB714 and IB937) and procyanidins. Overall, the results obtained suggest that, along with tannins, other polyphenols present in red wine, namely pyranoanthocyanins, could actively contribute to red wine global astringency.

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420

Astruc, D. ; Boisselier, E. ; Ornelas, C. Dendrimers Designed for Functions: From Physical, Photophysical, and Supramolecular Properties to Applications in Sensing, Catalysis, Molecular Electronics, Photonics, and Nanomedicine. Chem. Rev. 2010, 110 , 1857– 1959, DOI: 10.1021/cr900327d

[ACS Full Text ], [CAS], Google Scholar

420

Dendrimers Designed for Functions: From Physical, Photophysical, and Supramolecular Properties to Applications in Sensing, Catalysis, Molecular Electronics, Photonics, and Nanomedicine

Astruc, Didier; Boisselier, Elodie; Ornelas, Catia

Chemical Reviews (Washington, DC, United States) (2010), 110 (4), 1857-1959CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)

A review. The properties, functions and applications of dendrimers are reviewed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXktFektbw%253D&md5=d068a87b96269a35dd6c634b81cf3be2

421

Caminade, A.-M.; Turrin, C.-O.; Laurent, R.; Ouali, A.; Delavaux-Nicot, B. Dendrimers: Towards Catalytic, Material and Biomedical Uses; John Wiley & Sons, Ltd: Chichester, UK, 2011; pp 1– 566.

422

Yesil-Celiktas, O. ; Pala, C. ; Cetin-Uyanikgil, E. O. ; Sevimli-Gur, C. Synthesis of Silica-Pamam Dendrimer Nanoparticles as Promising Carriers in Neuro Blastoma Cells. Anal. Biochem. 2017, 519 , 1– 7, DOI: 10.1016/j.ab.2016.12.004

[Crossref], [PubMed], [CAS], Google Scholar

422

Synthesis of silica-PAMAM dendrimer nanoparticles as promising carriers in Neuro blastoma cells

Yesil-Celiktas, Ozlem; Pala, Cansu; Cetin-Uyanikgil, E. Oyku; Sevimli-Gur, Canan

Analytical Biochemistry (2017), 519 (), 1-7CODEN: ANBCA2; ISSN:0003-2697. (Elsevier B.V.)

Mesoporous silica carriers are emerging as therapeutic drug delivery systems. The objective of this study was to develop a formulation for synthesizing silica-PAMAM dendrimer hybrid nanoparticles with sol-gel technique. Subsequently, black carrot anthocyanins were encapsulated and investigated for their capability in terms of inhibiting the proliferative effects of neuroblastoma (Neuro 2A). In this context, particle size distributions were ascertained followed by thermal anal., SEM and encapsulation efficiency. Subsequently, in vitro release kinetics was detd. along with cytotoxicity of empty and anthocyanin doped hybrid nanoparticles. The lowest particle size was 134.8 nm with a zeta potential of +19.78 mV which enhanced electrostatic interaction with the cell membrane in the cytotoxicity analyses. As the anthocyanin content was totally released at the end of 6 days, the cytotoxicity was obsd. for 134 h, reaching an inhibition of 87.9%. On the other hand, Neuro 2A cells incubated with empty nanoparticles exhibited a high proliferation indicating that hybrid nanoparticles were not toxic to the cells and the inhibitory effect was assocd. with the anthocyanins.

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423

Cruz, L. ; Basílio, N. ; Mendoza, J. ; Mateus, N. ; de Freitas, V. ; Tawara, M. H. ; Correa, J. ; Fernandez-Megia, E. Impact of a Water-Soluble Gallic Acid-Based Dendrimer on the Color-Stabilizing Mechanisms of Anthocyanins. Chem. - Eur. J. 2019, 25 , 11696– 11706, DOI: 10.1002/chem.201901912

[Crossref], [PubMed], [CAS], Google Scholar

423

Impact of a Water-Soluble Gallic Acid-Based Dendrimer on the Color-Stabilizing Mechanisms of Anthocyanins

Cruz, Luis; Basilio, Nuno; Mendoza, Johan; Mateus, Nuno; de Freitas, Victor; Tawara, Maun H.; Correa, Juan; Fernandez-Megia, Eduardo

Chemistry - A European Journal (2019), 25 (50), 11696-11706CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)

The interaction of two anthocyanins with a water-sol. polyanionic dendrimer was studied through UV/Vis, stopped-flow, and NMR spectroscopy. Cyanidin-3-glucoside (cy3glc) revealed a stronger interaction than malvidin-3-glucoside (mv3glc) at pH 1 according to their apparent assocn. consts. A higher color increased was also obtained for cy3glc at pH 3.5 as a result of this stronger interaction. A high-frequency chem. shift of the cy3glc arom. protons suggest the formation of ionic pairs. The interaction parameters (K≈700 M-1, n≈295) indicated the binding of approx. two anthocyanin mols. by each sulfate group. The equil. and rate consts. of cy3glc in the presence of dendrimer showed an increased stability of the flavylium cation and a higher protection of this species from hydration (pK'a and pKh increased almost one pH unit). The tuning and color stabilization of anthocyanins by using this dendrimer allow novel applications as colorimetric sensors for food packaging.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFyjs7%252FO&md5=1df6649432adb0bfc851b419a40cd194

424

Silva-Pereira, M. C. ; Teixeira, J. A. ; Pereira-Júnior, V. A. ; Stefani, R. Chitosan/Corn Starch Blend Films with Extract from Brassica Oleraceae (Red Cabbage) as a Visual Indicator of Fish Deterioration. LWT-Food Sci. Technol. 2015, 61 , 258– 262, DOI: 10.1016/j.lwt.2014.11.041

[Crossref], [CAS], Google Scholar

424

Chitosan/corn starch blend films with extract from Brassica oleraceae (red cabbage) as a visual indicator of fish deterioration

Silva-Pereira, Mayra Cristina; Teixeira, Jose Augusto; Pereira-Junior, Valdir Aniceto; Stefani, Ricardo

LWT--Food Science and Technology (2015), 61 (1), 258-262CODEN: LSTWB3; ISSN:0023-6438. (Elsevier Ltd.)

Chitosan and Starch are polymers that can be obtained from renewable sources, with good film-forming properties and many applications in food industry, such as active and smart-packaging, which can monitor and inform consumers about food conditions in real-time. Hence, we report here a system for pH monitoring based on Chitosan, Corn Starch and red cabbage ext., all inexpensively obtained from renewable sources. The system was produced from medium mol. wt. Chitosan, Corn-Starch and phytochem. ext. from Brassica oleracea var. capitata (Red Cabbage). TG-DSC, FT-IR, Water Vapor Transmission Rate, as well as light microscopy were used to characterize the system. The color variation after activation in different pH range was measured with the CIELab methodol. In order to validate the use of this system as a fish spoilage detection sensor, application tests were conducted with fish fillets. The results show that the system has good optical and morphol. properties and is very sensitive to pH variations. During the application test, the system visually indicated pH changes. Thus, the system shows a clear response to pH variation of the samples. Therefore, it has potential to be used as a visual indicator of the storage and consumption conditions of food.

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425

Choi, I. ; Lee, J. Y. ; Lacroix, M. ; Han, J. Intelligent Ph Indicator Film Composed of Agar/Potato Starch and Anthocyanin Extracts from Purple Sweet Potato. Food Chem. 2017, 218 , 122– 128, DOI: 10.1016/j.foodchem.2016.09.050

[Crossref], [PubMed], [CAS], Google Scholar

425

Intelligent pH indicator film composed of agar/potato starch and anthocyanin extracts from purple sweet potato

Choi, Inyoung; Lee, Jun Young; Lacroix, Monique; Han, Jaejoon

Food Chemistry (2017), 218 (), 122-128CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier Ltd.)

A new colorimetric pH indicator film was developed using agar, potato starch, and natural dyes extd. from purple sweet potato, Ipomoea batatas. Both agar and potato starch are solid matrixes used to immobilize natural dyes, anthocyanins. The UV-visible (UV-vis) spectrum of anthocyanin ext. solns. and agar/potato starch films with anthocyanins showed color variations to different pH values (pH 2.0-10.0). Fourier transform IR (FT-IR) and UV-vis region spectra showed compatibility between agar, starch, and anthocyanin exts. Color variations of pH indicator films were measured by a colorimeter after immersion in different pH buffers. An application test was conducted for potential use as a meat spoilage sensor. The pH indicator films showed pH changes and spoilage point of pork samples, changing from red to green. Therefore, the developed pH indicator films could be used as a diagnostic tool for the detection of food spoilage.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFWmtrfK&md5=706b0ba09a70539708c49295a7ebd1ff

426

Yoshida, C. M. P. ; Maciel, V. B. V. ; Mendonça, M. E. D. ; Franco, T. T. Chitosan Biobased and Intelligent Films: Monitoring Ph Variations. LWT-Food Sci. Technol. 2014, 55 , 83– 89, DOI: 10.1016/j.lwt.2013.09.015

[Crossref], [CAS], Google Scholar

426

Chitosan biobased and intelligent films: Monitoring pH variations

Yoshida, Cristiana M. P.; Maciel, Vinicius Borges V.; Mendonca, Mariana Eleonora D.; Franco, Telma Teixeira

LWT--Food Science and Technology (2014), 55 (1), 83-89CODEN: LSTWB3; ISSN:0023-6438. (Elsevier Ltd.)

Many factors can influence the shelf-life product, such as pH, water activity, nutrient levels available oxygen, etc. Variations in food pH could occur due to microorganism growth and chem. reactions that may impact flavor, consistency and shelf-life. The objective of this paper was to obtain and characterize the fast pH-colorimetric indicator device, applying a simple manufg. technique, using food grade and biodegradable materials. The intelligent film was based on natural compds. as chitosan and anthocyanin (pH-colorimetric indicator). Chitosan intelligent films (C-ATH, 2.0 g/100 g) were obtained incorporating anthocyanin (1.0 g/100 g) in matrix films. Initially, a dark violet color was obsd. in chitosan films dried. When immersed in different pH buffers, the color range of the films varied from pink (in acid pH) to bluish-green (in neutral pH) and to violet (in basic pH). The water soly. and water vapor transmission rate of C-ATH were decreased to 60% and 48%, resp., as compared to control film (CF, without indicator). The mech. properties such as tensile strength and rigidity were maintained, and the elongation at break was reduced to 47% compared to CF. The advantages of this system were the simple manufg. process, biodegradability and usage of natural and safe compds.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1WitL3F&md5=82a2e7620720a6d4ca8ec4943d018e9d

427

Pourjavaher, S. ; Almasi, H. ; Meshkini, S. ; Pirsa, S. ; Parandi, E. Development of a Colorimetric Ph Indicator Based on Bacterial Cellulose Nanofibers and Red Cabbage (Brassica Oleraceae) Extract. Carbohydr. Polym. 2017, 156 , 193– 201, DOI: 10.1016/j.carbpol.2016.09.027

[Crossref], [PubMed], [CAS], Google Scholar

427

Development of a colorimetric pH indicator based on bacterial cellulose nanofibers and red cabbage (Brassica oleraceae) extract

Pourjavaher, Simin; Almasi, Hadi; Meshkini, Saeed; Pirsa, Sajad; Parandi, Ehsan

Carbohydrate Polymers (2017), 156 (), 193-201CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

This work aimed to develop and characterize a smart label for pH monitoring based on bacterial cellulose (BC) nanofibers doped with anthocyanins extd. from red cabbage (Brassica oleracea). The relationship between the concn. of anthocyanins (32 and 193 mg L-1) and the morphol. properties and color response efficiency of pH indicator labels was investigated. The FT-IR results reflected that some new interactions have occurred between BC membrane and anthocyanins. The XRD analyses showed a decrease in diffraction intensities of BC by addn. of concd. form of anthocyanins. SEM results indicated that concd. anthocyanins caused to partial disintegration and deformation of the cellulose microfibrils with more cracks on the labels. But the intrinsic morphol. and structure of the BC nanofibers were preserved by addn. of dild. anthocyanins. A concn. dependent decrease was obsd. in the tensile strength of anthocyanin loaded labels but elongation percentage and moisture absorption of BC was increased by addn. of anthocyanins. The color variation in different pH range (2-10) was measured with the CIELab methodol. The label contg. dild. anthocyanins showed a more clear response to pH variation. Therefore, it has potential to be used as a visual indicator of the pH variations during storage of packaged food.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsFamsb3I&md5=56e97339aa9129404fc38607af96af14

428

Pereira, V. A., Jr ; de Arruda, I. N. Q. ; Stefani, R. Active Chitosan/Pva Films with Anthocyanins from Brassica Oleraceae (Red Cabbage) as Time–Temperature Indicators for Application in Intelligent Food Packaging. Food Hydrocolloids 2015, 43 , 180– 188, DOI: 10.1016/j.foodhyd.2014.05.014

[Crossref], [CAS], Google Scholar

428

Active chitosan/PVA films with anthocyanins from Brassica oleraceae (Red Cabbage) as Time-Temperature Indicators for application in intelligent food packaging

Pereira, Valdir Aniceto; de Arruda, Iza Natalia Queiroz; Stefani, Ricardo

Food Hydrocolloids (2015), 43 (), 180-188CODEN: FOHYES; ISSN:0268-005X. (Elsevier Ltd.)

Food-packaging featuring Time-Temp. Indicators are among the so-called intelligent packages. They use a system that monitors a food's condition in real-time, thus indicating the overall influence of temp. on food product quality. This work aimed to develop and characterize a Time-Temp. Indicator (TTI) based on a PVA/Chitosan polymeric doped with anthocyanins in order to indirectly indicate food quality changes through the detection of changes in the pH of packaged food products when subjected to improper storage temps. The TTI was produced from chitosan, PVA and anthocyanins extd. from Brassica oleracea var. capitata (Red Cabbage). TG-DSC, FT-IR, UV-Vis, as well as Swelling Index (Si) techniques were used to characterize the TTI. The color variation after activation by different pH values was measured through the CIELab scale. The mech. properties of the TTI were established through stress/strain tests. Due to its physicochem. features, the developed TTI offers attractive features for application in intelligent food packaging, even though it presents a divergent modulus of elasticity in comparison to com. polymers applied in food packaging. Application of the TTI presented here is supported by an activation test on pasteurized milk, with evident changes in the coloration of the film, which is important for indicating to consumers that the food has been subjected to changes in its chem. compn.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXpvVSksrg%253D&md5=82263c17931752a84a4fbec396cc78d7

429

Pacquit, A. ; Frisby, J. ; Diamond, D. ; Lau, K. T. ; Farrell, A. ; Quilty, B. ; Diamond, D. Development of a Smart Packaging for the Monitoring of Fish Spoilage. Food Chem. 2007, 102 , 466– 470, DOI: 10.1016/j.foodchem.2006.05.052

[Crossref], [CAS], Google Scholar

429

Development of a smart packaging for the monitoring of fish spoilage

Pacquit, Alexis; Frisby, June; Diamond, Danny; Lau, King Tong; Farrell, Alan; Quilty, Brid; Diamond, Dermot

Food Chemistry (2007), 102 (2), 466-470CODEN: FOCHDJ; ISSN:0308-8146. (Elsevier B.V.)

There is much interest from the fisheries industry in developing rapid methods to evaluate real-time freshness of fish and seafood products. Emphasis is on the ones that would reflect and account for the products history and their storage conditions from "harvest-to-home". The development of a "smart packaging" that monitors the microbial breakdown products in the headspace of packaged fish is described. When fish spoils it releases a variety of basic volatile amines which are detectable with appropriate pH indicating sensors. These are prepd. by entrapping within a polymer matrix a pH sensitive dye that responds, through visible color changes to the spoilage volatile compds. that contribute to a quantity known as total volatile basic nitrogen (TVB-N). Lab. trials on fresh fish filets showed that the sensor accurately tracks the increase in amines concn. in the package headspace. The response was also found to correlate to changing microbial populations (total viable count or TVC and Pseudomonas spp.). In addn., leaching of the dye was assessed over time to assess the suitability of the sensor formulation for food packaging application.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlWqu7fI&md5=d52cd5ed221fb1d809f6285fc8c64ac7

430

Maciel, V. B. V. ; Yoshida, C. M. P. ; Franco, T. T. Chitosan/Pectin Polyelectrolyte Complex as a Ph Indicator. Carbohydr. Polym. 2015, 132 , 537– 545, DOI: 10.1016/j.carbpol.2015.06.047

[Crossref], [PubMed], [CAS], Google Scholar

430

Chitosan/pectin polyelectrolyte complex as a pH indicator

Maciel, Vinicius Borges V.; Yoshida, Cristiana M. P.; Franco, Telma Teixeira

Carbohydrate Polymers (2015), 132 (), 537-545CODEN: CAPOD8; ISSN:0144-8617. (Elsevier Ltd.)

A polyelectrolyte complex (PEC) matrix formed between chitosan and pectin was developed to entrap a bioactive compd. (anthocyanin), obtaining an useful pH indicator device. Polysaccharides of opposite charges such as chitosan and pectin can have a very strong intermol. interaction. The innovation lies in obtaining a new system based on natural and biodegradable compds., which is simple to manuf., to indicate variation in pH by visual changes in color. This device has potential applications in food packaging. The PEC was studied using chitosan and pectin solns. at different pHs values (3.0, 4.0, 5.0 and 5.5) and pectin/chitosan molar ratios (1.0 to 10/1.0 to 5.0). PEC films were homogeneous and showed the highest yield (60.0%) at pH 5.5. Diffusion tests indicated efficient bioactive compd. entrapment in the PEC matrix. Thermogravimetric anal. (TGA), SEM (SEM) and Fourier transform IR (FTIR) spectroscopy indicate the compatibility between the polymers and bioactive compd.

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431

Maciel, V. B. V. ; Yoshida, C. M. P. ; Franco, T. T. Development of a Prototype of a Colourimetric Temperature Indicator for Monitoring Food Quality. J. Food Eng. 2012, 111 , 21– 27, DOI: 10.1016/j.jfoodeng.2012.01.037

432

Lakade, A. J. ; Sundar, K. ; Shetty, P. H. Nanomaterial-Based Sensor for the Detection of Milk Spoilage. LWT-Food Sci. Technol. 2017, 75 , 702– 709, DOI: 10.1016/j.lwt.2016.10.031

[Crossref], [CAS], Google Scholar

432

Nanomaterial-based sensor for the detection of milk spoilage

Lakade, Ankita Jagannath; Sundar, K.; Shetty, Prathapkumar H.

LWT--Food Science and Technology (2017), 75 (), 702-709CODEN: LSTWB3; ISSN:0023-6438. (Elsevier Ltd.)

The present study shows a simple, rapid; highly sensitive and economical assay for gradation of milk quality based on lactic acid in milk using cysteine modified silver nanoparticles. Cysteine helps in the binding of silver nanoparticles (AgNPs) and lactic acid (LA) leading to the aggregation of nanoparticles resulting in visible color change. With the increase in the acid content, the increase in aggregation of the nanoparticles leading to the distinct change in color was obsd. Milk spoilage was detd. by analyzing the pH, acidity, lactic acid concn., Lactic Acid Bacteria (LAB) count, alc. test and Clot on Boiling (COB) test. Based on these analyses, milk samples were categorized as fresh, pre-spoiled and spoiled. The UV-Visible spectrum, Dynamic Light Scattering, and Raman spectroscopy show spectral shift and aggregation of the synthesized AgNP-cysteine conjugate with pre-spoiled and spoiled milk and resulting in corresponding color change. In the presence of Lactic Acid, Cysteine induces the aggregation of AgNPs leading to a change in yellow color of the AgNP to orange - red -purple. The control milk, pre-spoiled milk, and spoiled milk shows the color change from yellow to red - orange to gray-blue resp.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslSmsr3N&md5=efa6167e88ecb203ccf6e6bdf35f0ddf

433

Kuswandi, B. ; Jayus ; Restyana, A. ; Abdullah, A. ; Heng, L. Y. ; Ahmad, M. A Novel Colorimetric Food Package Label for Fish Spoilage Based on Polyaniline Film. Food Control 2012, 25 , 184– 189, DOI: 10.1016/j.foodcont.2011.10.008

[Crossref], [CAS], Google Scholar

433

A novel colorimetric food package label for fish spoilage based on polyaniline film

Kuswandi, Bambang; Jayus; Restyana, Anggi; Abdullah, Aminah; Heng, Lee Yook; Ahmad, Musa

Food Control (2012), 25 (1), 184-189CODEN: FOOCEV; ISSN:0956-7135. (Elsevier Ltd.)

A novel colorimetric method based on polyaniline (PANI) film for the development of smart packaging, as a chem. sensor for real-time monitoring of the microbial breakdown products in the headspace of packaged fish is described. This on-package indicator contains PANI film, that responds through visible color change to a variety of basic volatile amines (specifically known as total volatile basic nitrogen (TVBN)) released during fish spoilage period. The PANI film characteristics and its response to TVBN were studied. A kinetic approach was used to correlate the ammonia response of the PANI film to that of the fish spoilage. Color changes, in terms of total color difference of PANI, correlated well with TVBN levels of fish. Apart from TVBN, trials on milkfish sample (Chanos chanos) have verified that the PANI film response also correlates well with microbial growth patterns in fish samples, esp. the changing microbial populations (total viable count (TVC) and Pseudomonas spp.). These responses enabled the real-time monitoring of fish spoilage either at various const. temps. or with temp. fluctuations. The PANI film can be recycled several times using an acid soln. to regenerate the PANI surface. Thus, PANI film can be considered as a low-cost sensor suitable for smart packaging applications.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1Sqsb3M&md5=ab241f759e07b4b6023d235aedf656d7

434

Dudnyk, I. ; Janeček, E.-R. ; Vaucher-Joset, J. ; Stellacci, F. Edible Sensors for Meat and Seafood Freshness. Sens. Actuators, B 2018, 259 , 1108– 1112, DOI: 10.1016/j.snb.2017.12.057

[Crossref], [CAS], Google Scholar

434

Edible sensors for meat and seafood freshness

Dudnyk, Iuliia; Janecek, Emma-Rose; Vaucher-Joset, Joanne; Stellacci, Francesco

Sensors and Actuators, B: Chemical (2018), 259 (), 1108-1112CODEN: SABCEB; ISSN:0925-4005. (Elsevier B.V.)

Here, we present a sensor for food freshness based solely on food-derived material, specifically pectin and red-cabbage. As such the sensor film is edible and safe for use inside food packaging, facilitating its wide-spread use. The sensor is designed to be a colorimetric indicator of food freshness. It displays high sensitivity to gaseous amines and shows good agreement with std. degrdn. markers when tested against real food samples. The sensor was exposed to a series of synthetic amines including ammonia, cadaverine and pyridine, and showed colorimetric changes accompanied by changes in the films' UV-VIS absorption spectra. When exposed to the headspace above beef, chicken, shrimp or whiting (fish) samples the sensors showed clear colorimetric changes as the food samples degraded. Visual and measured changes in the films absorption showed good agreement with increases in total volatile basic nitrogen and total aerobic colony counting as measured in the food samples by std. E. U. methods and ISO 4833:2003 resp., demonstrating the films' utility as a food freshness sensor.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjsVChsA%253D%253D&md5=98bdf4563fc9082d21b5842236d25bb8

435

Li, Y. ; Wu, K. ; Wang, B. ; Li, X. Colorimetric Indicator Based on Purple Tomato Anthocyanins and Chitosan for Application in Intelligent Packaging. Int. J. Biol. Macromol. 2021, 174 , 370– 376, DOI: 10.1016/j.ijbiomac.2021.01.182

[Crossref], [PubMed], [CAS], Google Scholar

435

Colorimetric indicator based on purple tomato anthocyanins and chitosan for application in intelligent packaging

Li, Yana; Wu, Kaixuan; Wang, Beihai; Li, Xuezhong

International Journal of Biological Macromolecules (2021), 174 (), 370-376CODEN: IJBMDR; ISSN:0141-8130. (Elsevier B.V.)

Intelligent colorimetric indicator films were prepd. to monitor freshness/spoilage of milk and fish by incorporating purple tomato anthocyanin (PTA) into chitosan (CS) matrix via soln. casting method with PTA concn. (wt./wt., based on CS) of 10%, 30%, and 50%, resp. The pH-response, UV absorption, Swelling Index, and the mech. properties of CS/PTA films were detd. It was found that the color of the original CS/PTA films became darker with an improvement of PTA content and expressed well pH-sensitivity. With increasing of pH, the color of the CS/PTA films exposed to pH = 3-11 solns. became darker and the change in color of the CS/10% PTA film was the most discernable. The tensile strength and Young's modulus of the CS/PTA film was much lower than that of CS film, however, the elongation at breaking and Swelling Index were both improved by adding PTA. The intelligent films with 10% PTA changed their color during progressive spoilage of milk or fish, revealing their potential application for monitoring food freshness/spoilage.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXjs1yhsrc%253D&md5=50eaa1c040a41ec45f536edfb37468b1

436

Fenger, J. A. ; Moloney, M. ; Robbins, R. J. ; Collins, T. M. ; Dangles, O. The Influence of Acylation, Metal Binding and Natural Antioxidants on the Thermal Stability of Red Cabbage Anthocyanins in Neutral Solution. Food Funct. 2019, 10 , 6740– 6751, DOI: 10.1039/C9FO01884K

[Crossref], [PubMed], [CAS], Google Scholar

436

The influence of acylation, metal binding and natural antioxidants on the thermal stability of red cabbage anthocyanins in neutral solution

Fenger, Julie-Anne; Moloney, Micheal; Robbins, Rebecca J.; Collins, Thomas M.; Dangles, Olivier

Food & Function (2019), 10 (10), 6740-6751CODEN: FFOUAI; ISSN:2042-6496. (Royal Society of Chemistry)

The main red cabbage anthocyanins (pigments) are cyanidin glycosides bearing one or two acyl groups derived from hydroxycinnamic acids (HCAs). Through π-stacking interactions with the cyanidin chromophore, the HCA residues have a deep influence on the color expressed and its stability. In this work, a series of non-, mono- and diacylated anthocyanins were investigated in neutral soln. (pH 7 and 8), where the pigments exhibit purple to blue colors. Under such conditions, the gradual color loss obsd. is a combination of two distinct processes involving the cyanidin nucleus: reversible water addn. and irreversible autoxidn. By acidification to pH < 2, the colorless forms stemming from water addn. (hemiketal and chalcones) are converted to the red flavylium ion, thereby permitting the selective monitoring of the irreversible contribution. The kinetics of color loss and of true pigment degrdn. could thus be recorded for each pigment. The influence of iron - cyanidin binding and of antioxidants (caffeic acid, N-acetylcysteine) was also investigated. A complete kinetic anal. combining the anthocyanin colored and colorless forms and the degrdn. products is provided. Overall, it appears that acylation is crit. to color stability. For instance, the nonacylated pigment is rapidly bleached as a result of fast water addn. and its iron complex is too unstable to provide protection. By contrast, the diacylated pigments are efficiently protected against hydration but much more moderately against autoxidn., which on the other hand is inhibited by efficient iron binding and addn. of N-acetylcysteine. Finally, the diacylated pigments are much more resistant to bleaching by hydrogen peroxide (possibly produced by cyanidin autoxidn.) and bisulfite (a common food preservative).

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437

Duenas, M. ; Fulcrand, H. ; Cheynier, V. Formation of Anthocyanin-Flavanol Adducts in Model Solutions. Anal. Chim. Acta 2006, 563 , 15– 25, DOI: 10.1016/j.aca.2005.10.062

[Crossref], [CAS], Google Scholar

437

Formation of anthocyanin-flavanol adducts in model solutions

Duenas, M.; Fulcrand, H.; Cheynier, V.

Analytica Chimica Acta (2006), 563 (1-2), 15-25CODEN: ACACAM; ISSN:0003-2670. (Elsevier B.V.)

The mechanism of direct reactions between malvidin 3-O-glucoside (Mv3glc) and a flavanol monomer, (-)-epicatechin, was studied in model solns. in the pH range 2.0-6.0. The direct reactions are strongly related to pH. The rate of Mv3glc and epicatechin disappearance increased with pH. Nucleophilic addn. of epicatechin onto the flavylium form of Mv3glc took place at all pH values. At pH 2.0, the resulting intermediate flavene yielded a colorless Mv3glc-epicatechin adduct with an A-type linkage. In the range pH 3.2-6.0, two new products with UV-vis spectra characteristic of those of xanthylium ions and mass signals at m/z 633 and 453, resp., in the pos. ion mode were detected. These products are postulated to be degrdn. products of the flavylium form of Mv3glc-epicatechin arising from the intermediate flavene. Moreover, above pH 4.0, oxidn. of epicatechin promoted the formation of new pigments detected at m/z 781, in the pos. ion mode. These ions were attributed to epicatechin-Mv3glc adducts formed by addn. of Mv3glc onto the epicatechin o-quinone as the loss of a 138 amu fragment indicated a biphenyl or biphenyl-ether linkage between the flavanol B-ring and the anthocyanin A-ring.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XivVOhsro%253D&md5=11d7646ae0cb7b6ad933f62130ddf212

438

El-Meligy, A. B. ; Ishihara, T. ; Oyama, K. ; El-Nahas, A. M. ; Yoshida, K. The First Synthesis of 3-O-Methylcyanidin and the Effect of 3-O-Substitution on the Stability under Acidic Conditions. Heterocycles 2018, 97 , 946– 959, DOI: 10.3987/COM-18-S(T)74

[Crossref], [CAS], Google Scholar

438

The first synthesis of 3-O-methylcyanidin and the effect of 3-O-substitution on stability under acidic conditions

El-Meligy, Asmaa B.; Ishihara, Takehiro; Oyama, Kin-ichi; El-Nahas, Ahmed M.; Yoshida, Kumi

Heterocycles (2018), 97 (2, Spec. Issue), 946-959CODEN: HTCYAM; ISSN:1881-0942. (Japan Institute of Heterocyclic Chemistry)

The simplest and most common anthocyanin in nature is 3-O-glucosylcyanidin, and 3-O-glucosylation is believed to stabilize the chromophore. To clarify the effect of the glucose residue we compared the stability of 3-O-glucosylcyanidin with its aglycon, cyanidin, and newly synthesized 3-O-methylcyanidin. We also analyzed the co-pigmentation effect of flavocommelin and rutin, on the color and stability of 3-O-substituted cyanidins and cyanidin. The bathochromic shift of λvismax and stability of the color by addn. of flavocommelin was greater than that of rutin. flavocommelin might stack closer and stronger to the anthocyanidin chromophore than rutin.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXpt1ynu74%253D&md5=d4ce45664e906599acc3a4979e376566

439

Lopes, P. ; Richard, T. ; Saucier, C. ; Teissedre, P.-L. ; Monti, J.-P. ; Glories, Y. Anthocyanone A: A Quinone Methide Derivative Resulting from Malvidin 3-O-Glucoside Degradation. J. Agric. Food Chem. 2007, 55 , 2698– 2704, DOI: 10.1021/jf062875o

[ACS Full Text ], [CAS], Google Scholar

439

Anthocyanone A: A Quinone Methide Derivative Resulting from Malvidin 3-O-Glucoside Degradation

Lopes, Paulo; Richard, Tristan; Saucier, Cedric; Teissedre, Pierre-Louis; Monti, Jean-Pierre; Glories, Yves

Journal of Agricultural and Food Chemistry (2007), 55 (7), 2698-2704CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A new compd. resulting from the oxidative degrdn. of malvidin 3-O-glucoside under acid conditions was detected in a wine model soln. stored under 90 and 25 °C. It was isolated by semi-preparative HPLC, and its structure was elucidated by UV-vis spectra, mass spectrometry (LC/MS), and NMR spectroscopy (1-D and 2-D). The compd. was identified as 8-β-D-glucopyranosyl-2,4-dihydroxy-6-oxo-cyclohexa-2,4-dienyl acetic acid (anthocyanone A), which results from nucleophilic attack of hydrogen peroxide to malvidin 3-O-glucoside through a Baeyer-Villiger oxidn. followed by other oxidns. steps.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXisVGlt7w%253D&md5=4356be5d65fd930abf897fdd99333f27

440

de Oliveira, K. G. ; Queiroz, V. A. V. ; Carlos, L. D. ; Cardoso, L. D. ; Pinheiro-Sant'Ana, H. M. ; Anunciacao, P. C. ; de Menezes, C. B. ; da Silva, E. C. ; Barros, F. Effect of the Storage Time and Temperature on Phenolic Compounds of Sorghum Grain and Flour. Food Chem. 2017, 216 , 390– 398, DOI: 10.1016/j.foodchem.2016.08.047

441

Cabrita, L. ; Petrov, V. ; Pina, F. On the Thermal Degradation of Anthocyanidins: Cyanidin. RSC Adv. 2014, 4 , 18939– 18944, DOI: 10.1039/C3RA47809B

[Crossref], [CAS], Google Scholar

441

On the thermal degradation of anthocyanidins: cyanidin

Cabrita, Luis; Petrov, Vesselin; Pina, Fernando

RSC Advances (2014), 4 (36), 18939-18944CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)

Cyanidin was studied by direct pH jumps (from equilibrated solns. at very low pH values to higher pH values) and reverse pH jumps (from equilibrated or not equilibrated solns. at higher pH values to very low ones). The kinetic steps of the direct and reverse pH jumps were followed by stopped flow, absorption spectroscopy and HPLC, at different timescales. The pH dependent rate const. of the slower kinetic process to reach the equil. follows a bell shaped curve as described for many synthetic flavylium compds. Unlike anthocyanins, it was proved that there is no pH dependent reversibility in the system, since the chalcone suffers an irreversible degrdn. process. The math. expression to describe the bell shaped behavior was deduced. These results contribute to explain why in plants glycosylation is crucial for the stabilization of the anthocyanins.

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442

Furtado, P. ; Figueiredo, P. ; das Neves, H. C. ; Pina, F. Photochemical and Thermal Degradation of Anthocyanins. J. Photochem. Photobiol., A 1993, 75 , 113– 118, DOI: 10.1016/1010-6030(93)80191-B

[Crossref], [CAS], Google Scholar

442

Photochemical and thermal degradation of anthocyanidins

Furtado, Paula; Figueiredo, Paulo; Chaves das Neves, Higuinaldo; Pina, Fernando

Journal of Photochemistry and Photobiology, A: Chemistry (1993), 75 (2), 113-18CODEN: JPPCEJ; ISSN:1010-6030.

Photochem. and thermal degrdn. of four anthocyanidins (pelargonidin, delphinidin, malvidin and cyanidin) in aq. acidic media was studied. The kinetics of the degrdn. were followed by absorption spectroscopy and high performance liq. chromatog. All anthocyanidins studied have shown a similar thermal degrdn. pattern. Chalcone was detected as an intermediary product, which undergoes cleavage yielding the final decompn. products, identified as 2,4,6-trihydroxybenzaldehyde originated from ring A for all four anthocyanidins, and 3,4,5-trihydroxybenzoic acid for delphinidin, 4-hydroxy-3,5-dimethoxybenzoic acid for malvidin, 3,4-dihydroxybenzoic acid for cyanidin, and 4-hydroxybenzoic acid for pelargonidin (all these originated from ring B). During the photochem. degrdn., the formation of the same final products as for thermal reaction was obsd., but through a different kinetic pathway involving the excitation of the flavylium cation. The substitution of the hydroxyl in position 3 by a glucoside gives rise to a large increase in the thermal stability, and a decrease in the quantum yield of the photochem. reaction.

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443

Woodward, G. ; Kroon, P. ; Cassidy, A. ; Kay, C. Anthocyanin Stability and Recovery: Implications for the Analysis of Clinical and Experimental Samples. J. Agric. Food Chem. 2009, 57 , 5271– 5278, DOI: 10.1021/jf900602b

[ACS Full Text ], [CAS], Google Scholar

443

Anthocyanin Stability and Recovery: Implications for the Analysis of Clinical and Experimental Samples

Woodward, Gary; Kroon, Paul; Cassidy, Aedin; Kay, Colin

Journal of Agricultural and Food Chemistry (2009), 57 (12), 5271-5278CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

The proportion of ingested anthocyanins to reach the systemic circulation is reported to be a small percentage of their ingested dose. This may be due to physiochem. degrdn. in vivo or following routine sample treatment. Therefore, this study aimed to quant. investigate the effect of anthocyanin structure on their stability under simulated (in vitro) physiol. conditions and to assess their degrdn. and recovery following routine preanal. sample extn. and storage. It was demonstrated that B-ring hydroxylation mediated the degrdn. of anthocyanins to their phenolic acid and aldehyde constituents, successful anthocyanin extn. is dependent on both sample prepn. technique and anthocyanin structure, and anthocyanins are stable through multiple freeze-thaw cycles. These data indicate that significant portions of ingested anthocyanins are likely to degrade to phenolic acids and aldehyde in vivo. Consequently, these compds. should be the target of future bioavailability and bioactivity studies to establish the true occurrence and impact of anthocyanins on human health.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlslemu7g%253D&md5=f1b750bafa994c1edcbc9db1b2f9efa3

444

Fenger, J. A. ; Robbins, R. J. ; Collins, T. M. ; Dangles, O. The Fate of Acylated Anthocyanins in Mildly Heated Neutral Solution. Dyes Pigm. 2020, 178 , 108326, DOI: 10.1016/j.dyepig.2020.108326

[Crossref], [CAS], Google Scholar

444

The fate of acylated anthocyanins in mildly heated neutral solution

Fenger, Julie-Anne; Robbins, Rebecca J.; Collins, Thomas M.; Dangles, Olivier

Dyes and Pigments (2020), 178 (), 108326CODEN: DYPIDX; ISSN:0143-7208. (Elsevier Ltd.)

In neutral soln., anthocyanins acylated by hydroxycinnamic acids typically exhibit attractive blue colors and a higher resistance to color loss compared to their nonacylated homologs. However, they remain vulnerable to a poorly understood combination of oxidative and hydrolytic reactions that strongly contribute to color loss and limits their industrial applications. In this work, the thermal degrdn. of isolated red cabbage anthocyanins (0, 1 or 2 acyl groups) at pH 7 was investigated by UPLC-DAD-MS (low- and high-resoln.). Non-oxidative alterations, including deacylation and intramol. acyl transfer, were obsd. and found very dependent on the no. and position of the acyl group(s) as well as on the presence of iron ions. At intermediate and advanced thermal degrdn., several oxidative mechanisms were evidenced that lead to protocatechuic acid, phloroglucinaldehyde 2-O-glucoside, acylglycosides and derivs. of 2,4,6-trihydroxyphenylacetic acid and 3,5,7-trihydroxycoumarin. Based on the product distribution obsd. and on the impact of added Fe2+ ions and H2O2, possible degrdn. mechanisms are discussed. They likely start with a one- or two-electron transfer from the anionic base (a major colored form in neutral soln.) to O2. The hydrogen peroxide produced could then further react as an electrophile with the anionic base and/or the hemiketal (major colorless hydrated form). This contribution to understanding the degrdn. mechanisms of anthocyanins around neutrality can open up new stabilization strategies to extend the range of their food applications to neutral media.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlsVWjur4%253D&md5=eafccd8ae553b4f846654a7c6b505178

445

[Crossref], [PubMed], [CAS], Google Scholar

445

Chemistry and applications of flavylium compounds: a handful of colours

Pina, Fernando; Melo, Maria J.; Laia, Cesar A. T.; Parola, A. Jorge; Lima, Joao C.

Chemical Society Reviews (2012), 41 (2), 869-908CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhvFKjuw%253D%253D&md5=503ff3ae3e25fb5b6f81e290590a6b62

446

Giestas, L. ; Folgosa, F. ; Lima, J. C. ; Parola, A. J. ; Pina, F. Bio-Inspired Multistate Networks Responsive to Light, Ph and Thermal Inputs – an Example of a Multistate System Operating through Different Algorithms. Eur. J. Org. Chem. 2005, 2005 , 4187– 4200, DOI: 10.1002/ejoc.200500318

447

Moncada, M. C. ; Fernández, D. ; Lima, J. C. ; Parola, A. J. ; Lodeiro, C. ; Folgosa, F. ; Melo, M. J. ; Pina, F. Multistate Properties of 7-(N,N-Diethylamino)-4′-Hydroxyflavylium. An Example of an Unidirectional Reaction Cycle Driven by Ph. Org. Biomol. Chem. 2004, 2 , 2802– 2808, DOI: 10.1039/B409260K

[Crossref], [PubMed], [CAS], Google Scholar

447

Multistate properties of 7-(N,N-diethylamino)-4'-hydroxyflavylium. An example of an unidirectional reaction cycle driven by pH

Moncada, Margarida C.; Fernandez, Damian; Lima, Joao C.; Parola, A. Jorge; Lodeiro, Carlos; Folgosa, Filipe; Melo, M. Joao; Pina, Fernando

Organic & Biomolecular Chemistry (2004), 2 (19), 2802-2808CODEN: OBCRAK; ISSN:1477-0520. (Royal Society of Chemistry)

The synthetic flavylium salt 7-(N,N-diethylamino)-4'-hydroxyflavylium tetrafluoroborate gives rise in aq. soln. to a complex network of chem. reactions driven by pH. The system was studied by 1H NMR, single crystal X-ray diffraction, steady state and transient UV-Vis spectrophotometry as well as stopped flow. The crystal structure shows a high degree of coplanarity between the pyrylium system and the Ph group in position 2. Thermodn. and kinetic consts. for the pH dependent network of chem. reactions were obtained. The introduction of an amino group in position 7 allows formation of protonated species leading, in particular, to a tautomeric form of the protonated cis-chalcone, CcH+, whose absorption spectra is rather red shifted, in comparison with the correspondent protonated trans-chalcone, CtH+. The CcH+ species can be rapidly converted into the flavylium cation through a first order process with lifetime of 0.2 s at pH = 2.35. This new reaction channel confers this compd. a peculiar behavior in acidic media, allowing to define an unidirectional pH driven reaction cycle.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnvFCnsLo%253D&md5=12f2aa084c2c35cbcf7b8a6eeefc13e4

448

Adaku, C. ; Skaar, I. ; Berland, H. ; Byamukama, R. ; Jordheim, M. ; Andersen, O. M. Anthocyanins from Mauve Flowers of Erlangea Tomentosa (Bothriocline Longipes) Based on Erlangidin - the First Reported Natural Anthocyanidin with C-Ring Methoxylation. Phytochem. Lett. 2019, 29 , 225– 230, DOI: 10.1016/j.phytol.2018.12.016

[Crossref], [CAS], Google Scholar

448

Anthocyanins from mauve flowers of Erlangea tomentosa (Bothriocline longipes) based on erlangidin - The first reported natural anthocyanidin with C-ring methoxylation

Adaku, Christopher; Skaar, Irene; Berland, Helge; Byamukama, Robert; Jordheim, Monica; Andersen, Oeyvind M.

Phytochemistry Letters (2019), 29 (), 225-230CODEN: PLHEBK; ISSN:1874-3900. (Elsevier B.V.)

Above 700 different anthocyanins have been isolated from plants. These flavonoid pigments are grouped after the no. and position of hydroxy- and methoxy-groups on their anthocyanidin A- and B-rings, which influence their properties. In this study two new anthocyanins, erlangidin 5-O-(4-(E-caffeoyl)-6-(malonyl)-β-glucopyranoside)-3-O-(6-(3II-(β-glucopyranosyl)-E-caffeoyl)-β-glucopyranoside) and erlangidin 5-O-(6-(malonyl)-β-glucopyranoside)-3-O-(6-(3II-(β-glucopyranosyl)-E-caffeoyl)-β-glucopyranoside) were isolated from purple flowers of Erlangea tomentosa (Bothriocline longipes) Oliv. & Hiern (Asteraceae) in amts. of ∼1.6 and 0.6 mg/g fr. wt., resp. They were found to contain the first reported natural anthocyanidin with a methoxy-group on the heterocyclic C-ring, which we have given the name erlangidin. During extn., isolation and storage in acidified methanolic solvents the two anthocyanins were both partly converted to their demalonylated and methylmalonyl esterified forms. Spectroscopic and chromatog. characteristics for erlangidin in comparison with the common anthocyanidins, which it might be mistaken for, are included.

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449

Wang, D. ; Ma, Y. ; Zhang, C. ; Zhao, X. Y. Thermal Characterization of the Anthocyanins from Black Soybean (Glycine Max L.) Exposed to Thermogravimetry. LWT-Food Sci. Technol. 2014, 55 , 645– 649, DOI: 10.1016/j.lwt.2013.10.007

[Crossref], [CAS], Google Scholar

449

Thermal characterization of the anthocyanins from black soybean (Glycine max L.) exposed to thermogravimetry

Wang, Dan; Ma, Yue; Zhang, Chao; Zhao, Xiaoyan

LWT--Food Science and Technology (2014), 55 (2), 645-649CODEN: LSTWB3; ISSN:0023-6438. (Elsevier Ltd.)

One anthocyanin compd., cyanin-3-glucoside, was isolated and identified by high performance liq. chromatog. tandem mass spectrometry (HPLC_MS/MS) from seed coat of black soybean variety, Heizi to assess its thermal characterization in vitro. The thermal characterization of anthocyanin was studied by thermogravimetry (TG) anal. The results from the TG curves showed the decompn. of anthocyanin occurred in three stages. Glucose cleaved from the cyanin-3-glucoside occurred in the first stage. Degrdn. of cyanin and small amts. of cyanin-3-glucoside appeared mainly in the second stage. The sugar in the anthocyanin was decompd. in the third stage. Thermodn. anal. was applied by free dynamic model. TG-isothermal expts. for the anthocyanins from black soybean seed coats confirmed the correct of the thermodn. anal.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs12ktr7L&md5=567fd645c60e7680370e09e7d3a08291

450

Das, A. B. ; Goud, V. V. ; Das, C. Degradation Kinetics of Anthocyanins from Purple Rice Bran and Effect of Hydrocolloids on Its Stability. J. Food Process Eng. 2020, 43 , e13360, DOI: 10.1111/jfpe.13360

451

Sadilova, E. ; Carle, R. ; Stintzing, F. C. Thermal Degradation of Anthocyanins and Its Impact on Color and in Vitro Antioxidant Capacity. Mol. Nutr. Food Res. 2007, 51 , 1461– 1471, DOI: 10.1002/mnfr.200700179

[Crossref], [PubMed], [CAS], Google Scholar

451

Thermal degradation of anthocyanins and its impact on color and in vitro antioxidant capacity

Sadilova, Eva; Carle, Reinhold; Stintzing, Florian C.

Molecular Nutrition & Food Research (2007), 51 (12), 1461-1471CODEN: MNFRCV; ISSN:1613-4125. (Wiley-VCH Verlag GmbH & Co. KGaA)

The aim of the current study was to thoroughly investigate the structural changes of anthocyanins at pH 3.5 in purified fractions from black carrot, elderberry and strawberry heated over 6 h at 95°C. Degrdn. products were monitored by HPLC-DAD-MS3 to elucidate the prevailing degrdn. pathways. In addn., alterations of color and antioxidant properties obsd. upon heating were scrutinized. Most interestingly, the degrdn. pathways at pH 3.5 were found to differ from those at pH 1. Among others, chalcone glycosides were detected at 320 nm in heat-treated elderberry and strawberry pigment isolates, and opening of the pyrylium ring initiated anthocyanin degrdn. In the case of acylated anthocyanins, acyl-glycoside moieties were split off from the flavylium backbone, first. Finally, for all pigment isolates, phenolic acids and phloroglucinaldehyde were the terminal degrdn. products as remainders of the B- and A-ring, resp. Maximum and min. antioxidant stabilizing capacities were found in black carrot and strawberry, resp., which was explained by the high degree of acylation in the former. After heating, decline of trolox equiv. antioxidant capacity (TEAC) was obsd. in all samples, which was attributed to both anthocyanins and their colorless degrdn. products following thermal exposure. As deduced from the ratio of TEAC value and anthocyanin content, the loss of anthocyanin bioactivity could not be compensated by the antioxidant capacity of newly formed colorless phenolics upon heating.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFyruw%253D%253D&md5=30877ad20234e861ef71dcc89e45c2c2

452

Sadilova, E. ; Stintzing, F. C. ; Carle, R. Thermal Degradation of Acylated and Nonacylated Anthocyanins. J. Food Sci. 2006, 71 , C504– C512, DOI: 10.1111/j.1750-3841.2006.00148.x

[Crossref], [CAS], Google Scholar

452

Thermal degradation of acylated and nonacylated anthocyanins

Sadilova, E.; Stintzing, F. C.; Carle, R.

Journal of Food Science (2006), 71 (8), C504-C512CODEN: JFDSAZ; ISSN:0022-1147. (Institute of Food Technologists)

The thermal degrdn. pathways of acylated and nonacylated anthocyanins from 3 com. sources were investigated. Strawberry, elderberry, and black carrot concs. were purified on XAD-16-HP and Sephadex-LH-20 columns to remove sugars, amino acids, salts, and phenolic compds., resp. The so obtained anthocyanin isolates were heated at 95 °C at pH 1, the optimum stability condition for the flavylium cation. During 7 h of thermal exposure, the samples were monitored by HPLC-DAD-MS3 at 280, 320, and 520 nm, resp., together with spectrophotometric color and anthocyanin assessment. Total anthocyanin content lightness, and chroma, but not hue angle, were appropriate parameters to monitor anthocyanin loss on a statistically significant level. Anthocyanin glycosides were generally cleaved by successive loss of sugar moieties and pentoses were more readily split off than hexoses. Anthocyanin aglycons were further degraded by scission into phloroglucinaldehyde (cyanidin, pelargonidin), 4-hydroxybenzoic acid (pelargonidin), and protocatechuic acid (cyanidin), the residues of the A- and B-rings, resp. Most interestingly, acylated cyanidin-triglycosides from black carrot were degraded into their corresponding diglycoside derivs., which are not genuine carrot pigments. Moreover, hydroxycinnamic acid glycosides were generated. It is therefore assumed that the thermal burden during processing of anthocyanic food can be deduced by monitoring the colored and colorless compd. profiles.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFWqtrjF&md5=32409637404f97655d5d426b64a36721

453

Chen, C.-C. ; Lin, C. ; Chen, M.-H. ; Chiang, P.-Y. Stability and Quality of Anthocyanin in Purple Sweet Potato Extracts. Foods 2019, 8 , 393, DOI: 10.3390/foods8090393

[Crossref], [CAS], Google Scholar

453

Stability and quality of anthocyanin in purple sweet potato extracts

Chen, Chin-Chia; Lin, Chi; Chen, Min-Hung; Chiang, Po-Yuan

Foods (2019), 8 (9), 393CODEN: FOODBV; ISSN:2304-8158. (MDPI AG)

Because of the high nutritional value of anthocyanin in purple sweet potatoes (TN57), the stability and quality of anthocyanin in purple sweet potatoes during and after the processing were investigated in this study. First of all, the extn. methods with different parameters, such as temp., time, solid-liq. ratio, pH value, and solvent were employed to get better extn. efficiencies. After that, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,20 -azino-bis (3-ethylbenz thiazoline-6-sulfonic acid) were used to evaluate the anti-oxidn. ability of the exts. Lastly, the thermal degrdn. kinetics and photodegrdn. were used to obtain important degrdn. factors including the content of anthocyanin residue, degrdn. index (DI), color parameters, reaction rate (k), and chromatic aberration (ΔE). We found that the extn. condition as using 60% ethanol with 1% citric acid under 80 °C for 40 min was optimal for purple sweet potatoes, which obtained antioxidant capacity as 333 μM TE DPPH, 376 μM TE ABTS+, and 593.6 μM TE ferric ion reducing antioxidant power (FRAP). The results indicate that the most important parameter for the stability of anthocyanin in the purple sweet potato ext. (PSPAE) was the pH value rather than temp. In addn., there was no significant difference in chromatic aberration between the light and dark storage conditions under 37 °C. Thus, PSPAE has the potential to be developed as health foods and drinks rich in anthocyanin.

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454

Sheldon, R. Metal-Catalyzed Oxidations of Organic Compounds, 1st ed.; Academic Press, 1981.

455

Vogel, F. ; Harf, J. ; Hug, A. ; von Rohr, P. R. Promoted Oxidation of Phenol in Aqueous Solution Using Molecular Oxygen at Mild Conditions. Environ. Prog. 1999, 18 , 7– 13, DOI: 10.1002/ep.670180114

[Crossref], [CAS], Google Scholar

455

Promoted oxidation of phenol in aqueous solution using molecular oxygen at mild conditions

Vogel, Frederic; Harf, Julien; Hug, Andreas; Von Rohr, Philipp Rudolf

Environmental Progress (1999), 18 (1), 7-13CODEN: ENVPDI; ISSN:0278-4491. (American Institute of Chemical Engineers)

Wet oxidn. with mol. O2 at mild conditions (temp. <200°, pressure ≤2 MPa) is an economically attractive pretreatment step for non-biodegradable aq. waste streams. To overcome the low reactivity of mol. O2 toward org. mols. at these mild process conditions, an initiator was used in combination with Fe2+ ions in the acidic range. The promoted oxidn. of phenol in aq. soln. was studied in a 4 L stirred autoclave. It was possible to degrade phenol at temps. as low as 100° without observing an induction time. The remaining soln. contained mainly acetic and formic acids and was quite biodegradable. The oxidative behavior of the O2/phenol system could be explained using the well-known autoxidn. mechanism for aliph. mols. 4-Hydroperoxyphenol is suggested as a key intermediate. Measured products were p-benzoquinone, hydroquinone, catechol, and maleic, oxalic, pyruvic, formic, and acetic acids; dimers were also identified in sample exts. A global pathway including all identified products is presented.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXislGmsL0%253D&md5=ea2c6e81e7812921013c4c0030ab4219

456

Janeiro, P. ; Brett, A. M. O. Redox Behavior of Anthocyanins Present in Vitis Vinifera L. Electroanalysis 2007, 19 , 1779– 1786, DOI: 10.1002/elan.200703941

[Crossref], [CAS], Google Scholar

456

Redox behavior of anthocyanins present in Vitis vinifera L

Janeiro, Patricia; Brett, Ana Maria Oliveira

Electroanalysis (2007), 19 (17), 1779-1786CODEN: ELANEU; ISSN:1040-0397. (Wiley-VCH Verlag GmbH & Co. KGaA)

Voltammetric techniques were employed to study the electrochem. behavior of several anthocyanins. The redox behavior of anthocyanins with the same basic structure, the influence of glycosylation on the redox behavior of anthocyanins derived from different anthocyanidins, and the influence of methoxylation were investigated. The anthocyanins used in this study were malvidin-3-O-glucoside chloride, malvidin-3,5-di-O-glucoside chloride, cyanidin-3-O-glucoside chloride, cyanidin-3,5-di-O-glucoside chloride, peonidin-3-O-glucoside chloride, delphinidin-3-O-glucoside chloride and the anthocyanidin petunidin chloride, all of them present in Vitis vinifera L. All hydroxyl groups of the anthocyanins can be electrochem. oxidized and the anthocyanins studied revealed a complex and pH dependent oxidn. process, with the occurrence of adsorption and of oxidn. products blocking the electrode surface.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtVCmtr3O&md5=b6e6671b561ac40c475d7df571ea3c47

457

Satake, R. ; Yanase, E. Mechanistic Studies of Hydrogen-Peroxide-Mediated Anthocyanin Oxidation. Tetrahedron 2018, 74 , 6187– 6191, DOI: 10.1016/j.tet.2018.09.012

[Crossref], [CAS], Google Scholar

457

Mechanistic studies of hydrogen-peroxide-mediated anthocyanin oxidation

Satake, Ryuya; Yanase, Emiko

Tetrahedron (2018), 74 (42), 6187-6191CODEN: TETRAB; ISSN:0040-4020. (Elsevier Ltd.)

The oxidn. of cyanidin-3-O-glucoside by hydrogen peroxide was investigated in a range of solvents. The reaction products had chem. structures identical to those formed by the reaction of this compd. with the alkylperoxyl radical 2,2'-azobis(2,4-dimethyl)valeronitrile. A plausible oxidn. mechanism was proposed based on the obtained reaction products, and this mechanism was confirmed by HPLC-MS expts. using 18O-labeled reagents. Further, the reaction conditions were found to influence both the reaction rate and the products formed during the transformation, which validated the proposed mechanism.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhslWisL3I&md5=605931f98bc7913068f3e484e72f368e

458

Nkhili, E. ; Loonis, M. ; Mihai, S. ; El Hajji, H. ; Dangles, O. Reactivity of Food Phenols with Iron and Copper Ions: Binding, Dioxygen Activation and Oxidation Mechanisms. Food Funct. 2014, 5 , 1186– 1202, DOI: 10.1039/C4FO00007B

[Crossref], [PubMed], [CAS], Google Scholar

458

Reactivity of food phenols with iron and copper ions: binding, dioxygen activation and oxidation mechanisms

Nkhili, Ezzohra; Loonis, Michele; Mihai, Simona; El Hajji, Hakima; Dangles, Olivier

Food & Function (2014), 5 (6), 1186-1202CODEN: FFOUAI; ISSN:2042-6496. (Royal Society of Chemistry)

In this work, the affinity of common dietary phenols (gallic acid, caffeic acid, catechin, and rutin) for iron and copper ions was quant. investigated in neutral phosphate buffer as well as the reactivity of the complexes toward dioxygen. Contrasting behaviors were obsd.: because of the competing phosphate ions, FeIII binding is much slower than FeII binding, which is rapidly followed by autoxidn. of FeII into FeIII. With both ions, O2 consumption and H2O2 prodn. are modest and the phenolic ligands are only slowly oxidized. By contrast, metal-phenol binding is fast with both CuI and CuII. With CuI, O2 consumption and H2O2 prodn. are very significant and the phenolic ligands are rapidly oxidized into a complex mixt. of oligomers. The corresponding mechanism with CuII is hampered by the preliminary rate-detg. step of CuII redn. by the phenols. The consequences of these findings for the stability and antioxidant activity of plant phenols are discussed.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXovVamsro%253D&md5=77763ac38850f0ebeab4bb188a86d896

459

Ryan, P. ; Hynes, M. J. The Kinetics and Mechanisms of the Complex Formation and Antioxidant Behaviour of the Polyphenols Egcg and Ecg with Iron(Iii). J. Inorg. Biochem. 2007, 101 , 585– 93, DOI: 10.1016/j.jinorgbio.2006.12.001

[Crossref], [PubMed], [CAS], Google Scholar

459

The kinetics and mechanisms of the complex formation and antioxidant behaviour of the polyphenols EGCg and ECG with iron(III)

Ryan, Paul; Hynes, Michael J.

Journal of Inorganic Biochemistry (2007), 101 (4), 585-593CODEN: JIBIDJ; ISSN:0162-0134. (Elsevier B.V.)

(-)-Epigallocatechin-gallate ((-)-EGCg) and (-)-epicatechin-gallate ((-)-ECG) are important antioxidants which are found in green tea. The kinetics and mechanisms of the reactions of a pseudo-first order excess of iron(III) with EGCg and ECG have been investigated in aq. soln. at 25 °C and an ionic strength of 0.5 M NaClO4. Mechanisms have been proposed which account satisfactorily for the kinetic data. These are consistent with a mechanism in which the 2:1 metal:ligand complex initially formed on reaction of iron(III) with the ligand subsequently decomps. in an electron transfer step. Complex formation takes place at two sep. binding sites via coupled reactions. Rate consts. of 4.28(±0.06) × 106 M-2 s-1 and 2.83(±0.04) × 106 M-2 s-1 have been evaluated for the reaction of monohydroxy Fe(OH)2+ species with EGCg and ECG, resp. while rate consts. for of 2.94(±0.4) × 104 M-2 s-1 and 2.41(±0.25) × 104 M-2 s-1 have been evaluated for the reaction of Fe3+ species with EGCg and ECG, resp. The iron(III) assisted decompn. of the initial iron(III) complex formed was also investigated and the rate consts. evaluated. Both the complex formation and subsequent electron transfer reactions of iron(III) with EGCg and ECG were monitored using UV-visible spectrophotometry. All of the suggested mechanisms and calcd. rate consts. are supported by calcns. carried out using global anal. of time dependant spectra. The results obtained show that one mol. of either EGCg or EGC is capable of reducing up to four iron(III) species, a fact which is consistent with the powerful antioxidant properties of the ligands.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXislKjsrs%253D&md5=1827f1f85fe54d749ac1a07bb598d326

460

Elstner, E. F. ; Osswald, W. Mechanisms of Oxygen Activation During Plant Stress. Proc. R. Soc. Edinburgh, Sect. B: Biol. Sci. 1994, 102 , 131– 154, DOI: 10.1017/S0269727000014068

[Crossref], [CAS], Google Scholar

460

Mechanisms of oxygen activation during plant stress

Elstner, Erich F.; Osswald, Wolfgang

Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences (1994), 102 (Oxygen and Environmental Stress in Plants), 131-54CODEN: PRSSDP; ISSN:0269-7270.

A review with 99 refs. Green plants, within certain limitations, can adapt to a wide variety of unfavorable conditions such as drought, temp. changes, light variations, infectious attacks, air pollution and soil contamination. Depending on the strength of the individual impact(s), fluent or abrupt changes in visible or measurable stress symptoms indicate the deviation from normal metabolic conditions. Most of the visible or measurable symptoms are connected with altered oxygen metab. principally concerning the transition from mostly heterolytic (two-electron transition) to increased homolytic (one-electron transition) processes. Homolytic reactions within metabolic sequences create, however, free radicals and have to be counteracted by the increase in radical-scavenging processes or compds., thus warranting reaction sequences under metabolic control. At later states of stress episodes, the above control is gradually lost and more or less chaotic radical processes take over. Finally, cellular decompartmentalizations induce lytic and necrotic processes which are visible as the collapse of darkening cells or tissues. Every episode during this process is governed by a more or less defined balance between pro- and antioxidative capacities, including photosynthetic (strongly under metabolic and oxygen-detoxifying control) and photodynamic (only controlled by scavenger- and/or quencher-availability) reactions. This (theor.) sequence of events in most cases can only be characterized punctually by strongly defined (anal.) indicator reactions (ESR) and is certainly species- and organ-specific.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXktlSqsrY%253D&md5=7659a72041aa06d0da2d94e5447ee685

461

Oren-Shamir, M. Does Anthocyanin Degradation Play a Significant Role in Determining Pigment Concentration in Plants?. Plant Sci. 2009, 177 , 310– 316, DOI: 10.1016/j.plantsci.2009.06.015

[Crossref], [CAS], Google Scholar

461

Does anthocyanin degradation play a significant role in determining pigment concentration in plants?

Oren-Shamir, Michal

Plant Science (Shannon, Ireland) (2009), 177 (4), 310-316CODEN: PLSCE4; ISSN:0168-9452. (Elsevier Ireland Ltd.)

A review. In contrast to the detailed knowledge available on anthocyanin synthesis, very little is known about its stability and catabolism in plants. Here we review evidence supporting in planta turnover and degrdn. of anthocyanins. Transient anthocyanin accumulation and disappearance during plant development or changes in environmental conditions suggest that anthocyanin degrdn. is controlled and induced when beneficial to the plant. Several enzymes have been isolated that degrade anthocyanins in postharvest fruit that may be candidates for in vivo degrdn. Three enzyme groups that control degrdn. rates of anthocyanins in fruit exts. and juices are polyphenol oxidases, peroxidases and β-glucosidases. Evidence supporting the involvement of peroxidases and β-glucosidases in in vivo anthocyanin degrdn. in Brunfelsia flowers is presented. Understanding the in vivo anthocyanin degrdn. process has potential for enabling increased pigmentation and prevention of color degrdn. in crops.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXpt1Kgs7w%253D&md5=12172fdf7e03349dd1fde9e4ca923d0c

462

Movahed, N. ; Pastore, C. ; Cellini, A. ; Allegro, G. ; Valentini, G. ; Zenoni, S. ; Cavallini, E. ; D'Incà, E. ; Tornielli, G. B. ; Filippetti, I. The Grapevine Vviprx31 Peroxidase as a Candidate Gene Involved in Anthocyanin Degradation in Ripening Berries under High Temperature. J. Plant Res. 2016, 129 , 513– 526, DOI: 10.1007/s10265-016-0786-3

[Crossref], [PubMed], [CAS], Google Scholar

462

The grapevine VviPrx31 peroxidase as a candidate gene involved in anthocyanin degradation in ripening berries under high temperature

Movahed, Nooshin; Pastore, Chiara; Cellini, Antonio; Allegro, Gianluca; Valentini, Gabriele; Zenoni, Sara; Cavallini, Erika; D'Inca, Erica; Tornielli, Giovanni Battista; Filippetti, Ilaria

Journal of Plant Research (2016), 129 (3), 513-526CODEN: JPLREA; ISSN:0918-9440. (Springer Japan)

Anthocyanin levels decline in some red grape berry varieties ripened under high-temp. conditions, but the underlying mechanism is not yet clear. Here we studied the effects of two different temp. regimes, representing actual Sangiovese (Vitis vinifera L.) viticulture regions, on the accumulation of mRNAs and enzymes controlling berry skin anthocyanins. Potted uniform plants of Sangiovese were kept from veraison to harvest, in two plastic greenhouses with different temp. conditions. The low temp. (LT) conditions featured av. and max. daily air temps. of 20 and 29 °C, resp., whereas the corresponding high temp. (HT) conditions were 22 and 36 °C, resp. The anthocyanin concn. at harvest was much lower in HT berries than LT berries although their profile was similar under both conditions. Under HT conditions, the biosynthesis of anthocyanins was suppressed at both the transcriptional and enzymic levels, but peroxidase activity was higher. This suggests that the low anthocyanin content of HT berries reflects the combined impact of reduced biosynthesis and increased degrdn., particularly the direct role of peroxidases in anthocyanin catabolism. Overexpression of VviPrx31 decreased anthocyanin contents in Petunia hybrida petals under heat stress condition. These data suggest that high temp. can stimulate peroxidase activity thus anthocyanin degrdn. in ripening grape berries.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitV2nsLk%253D&md5=62677cbebfbb8d8c34a4373b8116c773

463

Guo, J. ; Wang, M.-H. Ultraviolet a-Specific Induction of Anthocyanin Biosynthesis and Pal Expression in Tomato (Solanum Lycopersicum L.). Plant Growth Regul. 2010, 62 , 1– 8, DOI: 10.1007/s10725-010-9472-y

[Crossref], [CAS], Google Scholar

463

Ultraviolet A-specific induction of anthocyanin biosynthesis and PAL expression in tomato (Solanum lycopersicum L.)

Guo, Jia; Wang, Myeong-Hyeon

Plant Growth Regulation (2010), 62 (1), 1-8CODEN: PGRED3; ISSN:0167-6903. (Springer)

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptlGju70%253D&md5=d07f58b8a212123ebdbd950b88cb33eb

464

Jiang, M. ; Ren, L. ; Lian, H. ; Liu, Y. ; Chen, H. Novel Insight into the Mechanism Underlying Light-Controlled Anthocyanin Accumulation in Eggplant (Solanum Melongena L.). Plant Sci. 2016, 249 , 46– 58, DOI: 10.1016/j.plantsci.2016.04.001

[Crossref], [PubMed], [CAS], Google Scholar

464

Novel insight into the mechanism underlying light-controlled anthocyanin accumulation in eggplant (Solanum melongena L.)

Jiang, Mingmin; Ren, Li; Lian, Hongli; Liu, Yang; Chen, Huoying

Plant Science (Shannon, Ireland) (2016), 249 (), 46-58CODEN: PLSCE4; ISSN:0168-9452. (Elsevier Ireland Ltd.)

Eggplant is rich in anthocyanins, which are the major secondary metabolites and beneficial to human health. We discovered that the anthocyanin biosynthesis of eggplant cultivar 'Lanshan Hexian' was regulated by light. In this study, we isolated two blue light receptor genes, SmCRY1 and SmCRY2, and neg./pos. anthocyanin regulatory factors SmCOP1 and SmHY5 from eggplant. In terms of transcript levels, SmCRY1, SmCRY2 and SmHY5 were up-regulated by light, while SmCOP1 was down-regulated. Subsequently, the four genes were functionally complemented in phenotype of corresponding mutants, indicating that they act as counterparts of Arabidopsis genes. Yeast two-hybrid and bimol. fluorescence complementation assays showed that SmCRY1 and SmCRY2 interact with SmCOP1 in a blue-light-dependent manner. It also obtained the result that SmCOP1 interacts with SmHY5 and SmMYB1. Furthermore, using yeast one-hybrid assay, we found that SmHY5 and SmMYB1 both bind the promoters of anthocyanin biosynthesis structural genes (SmCHS and SmDFR). Taken together, blue-light-triggered CRY1/CRY2-COP1 interaction creates the condition that HY5 and MYB1 combine with the downstream anthocyanin synthesis genes (CHS and DFR) in eggplant. Our finding provides a new working model by which light controls anthocyanin accumulation in eggplant.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xps12ntLY%253D&md5=be0da12b1a30abca717ee4be2bc5eb4e

465

Qiu, Z. ; Wang, X. ; Gao, J. ; Guo, Y. ; Huang, Z. ; Du, Y. The Tomato Hoffman's Anthocyaninless Gene Encodes a Bhlh Transcription Factor Involved in Anthocyanin Biosynthesis That Is Developmentally Regulated and Induced by Low Temperatures. PLoS One 2016, 11 , e0151067 DOI: 10.1371/journal.pone.0151067

[Crossref], [PubMed], [CAS], Google Scholar

465

The tomato Hoffman's Anthocyaninless gene encodes a bHLH transcription factor involved in anthocyanin biosynthesis that is developmentally regulated and induced by low temperatures

Qiu, Zhengkun; Wang, Xiaoxuan; Gao, Jianchang; Guo, Yanmei; Huang, Zejun; Du, Yongchen

PLoS One (2016), 11 (3), e0151067/1-e0151067/22CODEN: POLNCL; ISSN:1932-6203. (Public Library of Science)

Anthocyanin pigments play many roles in plants, including providing protection against biotic and abiotic stresses. Many of the genes that mediate anthocyanin accumulation have been identified through studies of flowers and fruits; however, the mechanisms of genes involved in anthocyanin regulation in seedlings under low-temp. stimulus are less well understood. Genetic characterization of a tomato inbred line, FMTT271, which showed no anthocyanin pigmentation, revealed a mutation in a bHLH transcription factor (TF) gene, which corresponds to the ah (Hoffman's anthocyaninless) locus, and so the gene in FMTT271 at that locus was named ah. Overexpression of the wild type allele of AH in FMTT271 resulted in greater anthocyanin accumulation and increased expression of several genes in the anthocyanin biosynthetic pathway. The expression of AH and anthocyanin accumulation in seedlings was shown to be developmentally regulated and induced by lowtemperature stress. Addnl., transcriptome analyses of hypocotyls and leaves from the near-isogenic lines seedlings revealed that AH not only influences the expression of anthocyanin biosynthetic genes, but also genes assocd. with responses to abiotic stress. Furthermore, the ah mutation was shown to cause accumulation of reactive oxidative species and the constitutive activation of defense responses under cold conditions. These results suggest that AH regulates anthocyanin biosynthesis, thereby playing a protective role, and that this function is particularly important in young seedlings that are particularly vulnerable to abiotic stresses. The RNA-seq datahave been deposited in the NCBI Sequence ReadArchive (SRA) under accession no. SRP064591.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVChsLfP&md5=f4eeda35370eb728544219985503d005

466

Steyn, W. J. ; Wand, S. J. E. ; Holcroft, D. M. ; Jacobs, G. Anthocyanins in Vegetative Tissues: A Proposed Unified Function in Photoprotection. New Phytol. 2002, 155 , 349– 361, DOI: 10.1046/j.1469-8137.2002.00482.x

[Crossref], [PubMed], [CAS], Google Scholar

466

Anthocyanins in vegetative tissues: a proposed unified function in photoprotection

Steyn, W. J.; Wand, S. J. E.; Holcroft, D. M.; Jacobs, G.

New Phytologist (2002), 155 (3), 349-361CODEN: NEPHAV; ISSN:0028-646X. (Blackwell Science Ltd.)

A review. The function of anthocyanins in green, vegetative tissues has always been a contentious issue. Here we evaluate their proposed photoprotective function since recent findings have shown that anthocyanins reduce photoinhibition and photobleaching of chlorophyll under light stress conditions. Anthocyanins generally accumulate in peripheral tissues exposed to high irradiance, although there are some exceptions (e.g. accumulation in abaxial leaf tissues and in obligatory shade plants) and accumulation is usually transient. Anthocyanin accumulation requires light and generally coincides with periods of high excitation pressure and increased potential for photo-oxidative damage due to an imbalance between light capture, CO2 assimilation and carbohydrate utilization (e.g. greening of developing tissues, senescence and adverse environmental conditions). Light attenuation by anthocyanin may help to re-establish this balance and so reduce the risk of photo-oxidative damage. Although it has been suggested that anthocyanins may act as antioxidants, the assocn. between anthocyanins and oxidative stress appears to relate to the ability of anthocyanins to reduce excitation pressure and, hence, the potential for oxidative damage. The various aspects of anthocyanin induction and pigmentation presented here are compatible with, and support, the proposed general role of anthocyanins as photoprotective light screens in vegetative tissues.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xnt1Wmt7o%253D&md5=d61d16aab6232646333895ae14af583f

467

Barbagallo, R. N. ; Palmeri, R. ; Fabiano, S. ; Rapisarda, P. ; Spagna, G. Characteristic of Β-Glucosidase from Sicilian Blood Oranges in Relation to Anthocyanin Degradation. Enzyme Microb. Technol. 2007, 41 , 570– 575, DOI: 10.1016/j.enzmictec.2007.05.006

[Crossref], [CAS], Google Scholar

467

Characteristic of β-glucosidase from Sicilian blood oranges in relation to anthocyanin degradation

Barbagallo, R. N.; Palmeri, R.; Fabiano, S.; Rapisarda, P.; Spagna, G.

Enzyme and Microbial Technology (2007), 41 (5), 570-575CODEN: EMTED2; ISSN:0141-0229. (Elsevier B.V.)

Anthocyanin content in Sicilian sweet orange [Citrus sinensis (L) Osbeck] varieties known as blood oranges (Tarocco, Moro e Sanguinello) undergoes changes during the ripening process. Concn. increases during ripening, reaching a max. in the fully ripe fruit. At latter stage of maturity, a decrease of these pigments is obsd. This study aims to evaluate β-glucosidase activity (βG, EC 3.2.1.21) in Tarocco variety, the most common Sicilian blood orange, and to det. the main physicochem. and kinetic properties of this enzyme in order to underline its role on anthocyanins degrdn. during ripening. The enzymic ext. was assayed on both anthocyanins ext. from Tarocco juice and a synthetic substrate (p-nitrophenyl-β-D-glucopyranoside, pNPG). It was obsd. a 400 times higher specificity of the synthetic substrate than the natural substrate. Kinetic studies and physicochem. characterization of βG such as Vmax and Km (Vmax 2.1 × 10-2 and Km 2.67 × 10-4 using pNPG as substrate; Vmax 3.3 × 10-3 and Km 2.1 × 10-1 using natural substrate), optimum conditions of pH (4.5) and temp. (60 °C), fructose and glucose inhibition (competitive inhibition by glucose) and thermal stability (decimal redn. time 3 min at 75 °C and decimal redn. temp. 9.5 °C) were also performed. β-D-Glucosidase activity seems involved on anthocyanins degrdn. during final ripening stage of fruit.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXosF2ntro%253D&md5=af2e1e1e858d64f9d55ef06d2e89cd62

468

Quattrocchio, F. ; Verweij, W. ; Kroon, A. ; Spelt, C. ; Mol, J. ; Koes, R. Ph4 of Petunia Is an R2r3Myb Protein That Activates Vacuolar Acidification through Interactions with Basic-Helix-Loop-Helix Transcription Factors of the Anthocyanin Pathway. Plant Cell 2006, 18 , 1274– 1291, DOI: 10.1105/tpc.105.034041

[Crossref], [PubMed], [CAS], Google Scholar

468

PH4 of petunia is an R2R3 MYB protein that activates vacuolar acidification through interactions with basic-helix-loop-helix transcription factors of the anthocyanin pathway

Quattrocchio, Francesca; Verweij, Walter; Kroon, Arthur; Spelt, Cornelis; Mol, Joseph; Koes, Ronald

Plant Cell (2006), 18 (5), 1274-1291CODEN: PLCEEW; ISSN:1040-4651. (American Society of Plant Biologists)

The Petunia hybrida genes ANTHOCYANIN1 (AN1) and AN2 encode transcription factors with a basic-helix-loop-helix (BHLH) and a MYB domain, resp., that are required for anthocyanin synthesis and acidification of the vacuole in petal cells. Mutation of PH4 results in a bluer flower color, increased pH of petal exts., and, in certain genetic backgrounds, the disappearance of anthocyanins and fading of the flower color. PH4 encodes a MYB domain protein that is expressed in the petal epidermis and that can interact, like AN2, with AN1 and the related BHLH protein JAF13 in yeast two-hybrid assays. Mutation of PH4 has little or no effect on the expression of structural anthocyanin genes but strongly downregulates the expression of CAC16.5, encoding a protease-like protein of unknown biol. function. Constitutive expression of PH4 and AN1 in transgenic plants is sufficient to activate CAC16.5 ectopically. Together with the previous finding that AN1 domains required for anthocyanin synthesis and vacuolar acidification can be partially sepd., this suggests that AN1 activates different pathways through interactions with distinct MYB proteins.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XkslCmu7k%253D&md5=98bda36e31a17e0f77471ae908d02bde

469

Vaknin, H. ; Bar-Akiva, A. ; Ovadia, R. ; Nissim-Levi, A. ; Forer, I. ; Weiss, D. ; Oren-Shamir, M. Active Anthocyanin Degradation in Brunfelsia Calycina (Yesterday–Today–Tomorrow) Flowers. Planta 2005, 222 , 19– 26, DOI: 10.1007/s00425-005-1509-5

[Crossref], [PubMed], [CAS], Google Scholar

469

Active anthocyanin degradation in Brunfelsia calycina (yesterday-today-tomorrow) flowers

Vaknin, Hila; Bar-Akiva, Ayelet; Ovadia, Rinat; Nissim-Levi, Ada; Forer, Izhak; Weiss, David; Oren-Shamir, Michal

Planta (2005), 222 (1), 19-26CODEN: PLANAB; ISSN:0032-0935. (Springer)

Anthocyanins are the largest group of plant pigments responsible for colors ranging from red to violet and blue. The biosynthesis of anthocyanins, as part of the larger phenylpropanoid pathway, has been characterized in great detail. In contrast to the detailed mol. knowledge available on anthocyanin synthesis, very little is known about the stability and catabolism of anthocyanins in plants. In this study we present a preliminary characterization of active in planta degrdn. of anthocyanins, requiring novel mRNA and protein synthesis, in Brunfelsia calycina flowers. Brunfelsia is a unique system for this study, since the decrease in pigment concn. in its flowers (from dark purple to white) is extreme and rapid, and occurs at a specific and well-defined stage of flower development. Treatment of detached flowers with protein and mRNA synthesis inhibitors, at specific stages of flower development, prevented degrdn. In addn., treatment of detached flowers with cytokinins delayed senescence without changing the rate of anthocyanin degrdn., suggesting that degrdn. of anthocyanins is not part of the general senescence process of the flowers but rather a distinctive and specific pathway. Based on studies on anthocyanin degrdn. in wine and juices, peroxidases are reasonable candidates for the in vivo degrdn. A significant increase in peroxidase activity was shown to correlate in time with the rate of anthocyanin degrdn. An addnl. indication that oxidative enzymes are involved in the process is the fact that treatment of flowers with reducing agents, such as DTT and glutathione, caused inhibition of degrdn. This study represents the first step in the elucidation of the mol. mechanism behind in vivo anthocyanin degrdn. in plants.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVektr3L&md5=410c6f19ae17fef3c8ced34f5cb22764

470

Borovsky, Y. ; Oren-Shamir, M. ; Ovadia, R. ; De Jong, W. ; Paran, I. The a Locus That Controls Anthocyanin Accumulation in Pepper Encodes a Myb Transcription Factor Homologous to Anthocyanin2 of Petunia. Theor. Appl. Genet. 2004, 109 , 23– 9, DOI: 10.1007/s00122-004-1625-9

[Crossref], [PubMed], [CAS], Google Scholar

470

The A locus that controls anthocyanin accumulation in pepper encodes a MYB transcription factor homologous to Anthocyanin2 of Petunia

Borovsky, Yelena; Oren-Shamir, Michal; Ovadia, Rinat; De Jong, Walter; Paran, Ilan

Theoretical and Applied Genetics (2004), 109 (1), 23-29CODEN: THAGA6; ISSN:0040-5752. (Springer-Verlag)

Pepper plants contg. the dominant A gene accumulate anthocyanin pigments in the foliage, flower and immature fruit. The authors previously mapped A to pepper chromosome 10 in the F2 progeny of a cross between 5226 (purple-fruited) and PI 159234 (green-fruited) to a region that corresponds, in tomato, to the location of Petunia anthocyanin 2 (An2), a regulator of anthocyanin biosynthesis. This suggested that A encodes a homolog of Petunia An2. Using the sequences of An2 and a corresponding tomato expressed sequence tag, the authors isolated a pepper cDNA orthologous to An2 that cosegregated with A. The authors subsequently detd. the expression of A by Northern anal., using RNA extd. from fruits, flowers and leaves of 5226 and PI 159234. In 5226, expression was detected in all stages of fruit development and in both flower and leaf. In contrast, A was not expressed in the sampled tissues in PI 159234. Genomic sequence comparison of A between green- and purple-fruited genotypes revealed no differences in the coding region, indicating that the lack of expression of A in the green genotypes can be attributed to variation in the promoter region. By analyzing the expression of the structural genes in the anthocyanin biosynthetic pathway in 5226 and PI 159234, it was detd. that, similar to Petunia, the early genes in the pathway are regulated independently of A, while expression of the late genes is A-dependent.

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471

Povero, G. ; Gonzali, S. ; Bassolino, L. ; Mazzucato, A. ; Perata, P. Transcriptional Analysis in High-Anthocyanin Tomatoes Reveals Synergistic Effect of Aft and Atv Genes. J. Plant Physiol. 2011, 168 , 270– 279, DOI: 10.1016/j.jplph.2010.07.022

[Crossref], [PubMed], [CAS], Google Scholar

471

Transcriptional analysis in high-anthocyanin tomatoes reveals synergistic effect of Aft and atv genes

Povero, Giovanni; Gonzali, Silvia; Bassolino, Laura; Mazzucato, Andrea; Perata, Pierdomenico

Journal of Plant Physiology (2011), 168 (3), 270-279CODEN: JPPHEY; ISSN:0176-1617. (Elsevier GmbH)

Anthocyanins are high value plant antioxidants, which are not present in the fruits of the cultivated tomato. However, both the dominant gene Anthocyanin fruit (Aft) and the recessive gene atroviolacea (atv), when introgressed into the domesticated tomato from two different wild Solanum species, stimulate a limited anthocyanin pigmentation. Surprisingly, the double mutant Aft/Aft atv/atv gives rise to intensely purple pigmented tomatoes. A transcript profiling anal. was carried out using quant. RT-PCR and GeneChip Tomato Genome Arrays to identify differentially expressed genes when comparing Ailsa Craig, Aft/Aft, atv/atv, and Aft/Aft atv/atv fruits. Anthocyanin levels and the expression of the genes involved in anthocyanin prodn. and compartmentalization were higher in the peel of Aft/Aft atv/atv fruits than in the individual parental lines. Moreover, a synergistic effect of the two alleles Aft and atv on the transcription of specific anthocyanin genes and the activation of the whole anthocyanin pathway was obsd. Among the differentially expressed transcripts, genes involved in the phenylpropanoid pathway, biotic and abiotic stress responses, cell wall and hormone metab. were over-represented in Aft/Aft atv/atv fruit peel. Transcriptomic analyses thus revealed that the activation of anthocyanin synthesis in the peel of tomato fruit was accompanied by a complex remodulation of gene expression.

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472

Mennella, G. ; Lo Scalzo, R. ; Fibiani, M. ; D'Alessandro, A. ; Francese, G. ; Toppino, L. ; Acciarri, N. ; de Almeida, A. E. ; Rotino, G. L. Chemical and Bioactive Quality Traits During Fruit Ripening in Eggplant (S. Melongena L.) and Allied Species. J. Agric. Food Chem. 2012, 60 , 11821– 11831, DOI: 10.1021/jf3037424

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472

Chemical and Bioactive Quality Traits During Fruit Ripening in Eggplant (S. melongena L.) and Allied Species

Mennella, Giuseppe; Lo Scalzo, Roberto; Fibiani, Marta; DAlessandro, Antonietta; Francese, Gianluca; Toppino, Laura; Acciarri, Nazzareno; deAlmeida, Adelia Emilia; Rotino, Giuseppe Leonardo

Journal of Agricultural and Food Chemistry (2012), 60 (47), 11821-11831CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

A chem. and bioactive quality evaluation of phytochems. content of 10 eggplant lines and three allied species (S. sodomaeum, S. aethiopicum and S. integrifolium) was performed. The eggplant lines were divided into the two subgroups of delphinidin-3-rutinoside (D3R) and nasunin (NAS) typologies, on the basis of the anthocyanin detected in their fruit skin. The allied species had higher glycoalkaloids content, lower sol. solids and PPO activity and absence of anthocyanins compared to the eggplant lines; S. sodomaeum stood out for high phenols content. Orthogonal contrast revealed a higher sugar content and low PPO activity in NAS- compared to D3R-typologies, whereas higher chlorogenic acid and anthocyanin contents were present in D3R-typologies. The main effect of the ripening was a decrease in phenols and in the PPO activity, not evidenced in S. sodomaeum, and an increase of glycoalkaloids in overripe fruits.A good relationship was found between superoxide anion scavenging capacity and chlorogenic acid. This study highlighted the pattern of accumulation, also evidencing variations, of several phytochems. during the eggplant fruit development and ripening.

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473

Pandey, V. ; Awasthi, M. ; Singh, S. ; Tiwari, S. ; Dwivedi, U. A Comprehensive Review on Function and Application of Plant Peroxidases. Biochem. Anal. Biochem. 2017, 6 , 1000308, DOI: 10.4172/2161-1009.1000308

[Crossref], [CAS], Google Scholar

473

A comprehensive review on function and application of plant peroxidases

Pandey, Veda P.; Awasthi, Manika; Singh, Swati; Tiwari, Sameeksha; Dwivedi, Upendra N.

Biochemistry and Analytical Biochemistry (2017), 6 (1), 1000308/1-1000308/16CODEN: BABIFD; ISSN:2161-1009. (OMICS International)

Peroxidases, one of the key antioxidant enzymes, are widely distributed in nature and catalyze oxidn. of various electron donor substrates concomitant with the decompn. of H2O2. The non-animal plant peroxidases (class III peroxidase) are involved in various essential physiol. processes of plant growth and development throughout their life cycle. In view of the capability of peroxidases to catalyze the redox reaction for a wide range of substrates, they are considered as one of the important enzyme from the point of view of their various medicinal, biochem., immunol., biotechnol. and industrial applications. They have been successfully used for biopulping and biobleaching in the paper and textile industries. Peroxidases have also been used in org. synthesis, bioremediation, as well as various anal. applications in diagnostic kits, ELISA. Peroxidase based biosensors find application in anal. systems for detn. of hydrogen peroxide, glucose, alcs., glutamate, and choline etc. Thus, in view of array of physiol. functions as well as industrial applications, the peroxidases have conquered a dominant position in research groups and become one of the most extensively studied enzymes. In this direction, the present review embodies the classification, mechanism of action, major physiol. functions as well as industrial applications of plant peroxidases.

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474

Jolivet, S. ; Arpin, N. ; Wichers, H. J. ; Pellon, G. Agaricus Bisporus Browning: A Review. Mycol. Res. 1998, 102 , 1459– 1483, DOI: 10.1017/S0953756298006248

[Crossref], [CAS], Google Scholar

474

Agaricus bisporus browning: A review

Jolivet, Sylvie; Arpin, Noel; Wichers, Harry J.; Pellon, Gerard

Mycological Research (1998), 102 (12), 1459-1483CODEN: MYCRER; ISSN:0953-7562. (Cambridge University Press)

A review with many refs. Agaricus bisporus browning is a common and economically detrimental phenomenon, in which melanogenic phenols are enzymically processed into quinones, which evolve eventually to melanins. This review deals with the two fundamental sides of this process, enzyme(s) and phenolic substrates. Mushroom tyrosinase, the main polyphenol oxidase encountered in the A. bisporus sporophore, is treated in the first part. Its overall mol. architecture, isoforms, primary sequence and genetic background are considered. The presentation of tyrosinase catalytic features, including enzyme assays, kinetic properties, substrates and inhibitors, is followed by a comprehensive description of the active site and reaction mechanisms. Because of their relevance for studies of mushroom browning during development and post-harvest storage, the occurrence and properties of latent enzyme forms, as well as the location of tyrosinase and variations of its activity during the A. bisporus life cycle, are also reviewed. The second part deals with the substrates, particularly γ-L-glutaminyl-4-hydroxybenzene (GHB) and its derivs. Main data concerning the nature, obtention (by extn. or synthesis), spectrometric and chromatog. characteristics, chem. stabilities and biol. properties of these typical Agaricaceae compds. are presented. Their distribution and levels according to the strains and flushes are described, as well as their variations during storage. Thirdly, the relationship between browning and the natural or pathogenic discoloration intensity is developed.

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475

Suttirak, W.; Manurakchinakorn, S. Potential Application of Ascorbic Acid, Citric Acid and Oxalic Acid for Browning Inhibition in Fresh-Cut Fruits and Vegetables. Walailak J. Sci. Technol. 2010, 7. 5 14

476

Blokhina, O. ; Virolainen, E. ; Fagerstedt, K. ; Antioxidants, V. Oxidative Damage and Oxygen Deprivation Stress: A Review. Ann. Bot. 2003, 91 , 179– 94, DOI: 10.1093/aob/mcf118

[Crossref], [PubMed], [CAS], Google Scholar

476

Antioxidants, oxidative damage and oxygen deprivation stress: A review

Blokhina, Olga; Virolainen, Eija; Fagerstedt, Kurt V.

Annals of Botany (Oxford, United Kingdom) (2003), 91 (Spec. Issue), 179-194CODEN: ANBOA4; ISSN:0305-7364. (Oxford University Press)

A review. Oxidative stress is induced by a wide range of environmental factors including UV stress, pathogen invasion (hypersensitive reaction), herbicide action and oxygen shortage. Oxygen deprivation stress in plant cells is distinguished by three physiol. different states: transient hypoxia anoxia and reoxygenation. Generation of reactive oxygen species (ROS) is characteristic for hypoxia and esp. for reoxygenation. Of the ROS, hydrogen peroxide (H2O2) and superoxide (O2.-) are both produced in a no. of cellular reactions, including the iron-catalyzed Fenton reaction, and by various enzymes such as lipoxygenases, peroxidases, NADPH oxidase and xanthine oxidase. The main cellular components susceptible to damage by free radicals are lipids (peroxidn. of unsatd. fatty acids in membranes), proteins (denaturation), carbohydrates and nucleic acids. Consequences of hypoxia-induced oxidative stress depend on tissue and/or species (i.e. their tolerance to anoxia), on membrane properties, on endogenous antioxidant content and on the ability to induce the response in the antioxidant system. Effective utilization of energy resources (starch, sugars) and the switch to anaerobic metab. and the preservation of the redox status of the cell are vital for survival. The formation of ROS is prevented by an antioxidant system: low mol. mass antioxidants (ascorbic acid, glutathione, tocopherols), enzymes regenerating the reduced forms of antioxidants, and ROS-interacting enzymes such as SOD, peroxidases and catalases. In plant tissues many phenolic compds. (in addn. to tocopherols) are potential antioxidants: flavonoids, tannins and lignin precursors may work as ROS-scavenging compds. Antioxidants act as a cooperative network, employing a series of redox reactions. Interactions between ascorbic acid and glutathione, and ascorbic acid and phenolic compds. are well known. Under oxygen deprivation stress some contradictory results on the antioxidant status have been obtained. Expts. on overexpression of antioxidant prodn. do not always result in the enhancement of the antioxidative defense, and hence increased antioxidative capacity does not always correlate pos. with the degree of protection. Here, the authors present a consideration of factors which possibly affect the effectiveness of antioxidant protection under oxygen deprivation as well as under other environmental stresses. Such aspects as compartmentalization of ROS formation and antioxidant localization, synthesis and transport of antioxidants, the ability to induce the antioxidant defense and cooperation (and/or compensation) between different antioxidant systems are the determinants of the competence of the antioxidant system.

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477

Perron, N. R. ; Brumaghim, J. L. A Review of the Antioxidant Mechanisms of Polyphenol Compounds Related to Iron Binding. Cell Biochem. Biophys. 2009, 53 , 75– 100, DOI: 10.1007/s12013-009-9043-x

[Crossref], [PubMed], [CAS], Google Scholar

477

A Review of the Antioxidant Mechanisms of Polyphenol Compounds Related to Iron Binding

Perron, Nathan R.; Brumaghim, Julia L.

Cell Biochemistry and Biophysics (2009), 53 (2), 75-100CODEN: CBBIFV; ISSN:1085-9195. (Springer)

A review. In this review, primary attention is given to the antioxidant (and prooxidant) activity of polyphenols arising from their interactions with iron both in vitro and in vivo. In addn., an overview of oxidative stress and the Fenton reaction is provided, as well as a discussion of the chem. of iron binding by catecholate, gallate, and semiquinone ligands along with their stability consts., UV-vis spectra, stoichiometries in soln. as a function of pH, rates of iron oxidn. by O2 upon polyphenol binding, and the published crystal structures for iron-polyphenol complexes. Radical scavenging mechanisms of polyphenols unrelated to iron binding, their interactions with copper, and the prooxidant activity of iron-polyphenol complexes are briefly discussed.

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478

Fisher, G. R. ; Gutierrez, P. L. Free Radical Formation and DNA Strand Breakage During Metabolism of Diaziquone by Nad(P)H Quinone-Acceptor Oxidoreductase (Dt-Diaphorase) and Nadph Cytochrome C Reductase. Free Radical Biol. Med. 1991, 11 , 597– 607, DOI: 10.1016/0891-5849(91)90141-O

[Crossref], [PubMed], [CAS], Google Scholar

478

Free radical formation and DNA strand breakage during metabolism of diaziquone by NAD(P)H quinone-acceptor oxidoreductase (DT-diaphorase) and NADPH cytochrome c reductase

Fisher, Geoffrey R.; Gutierrez, Peter L.

Free Radical Biology & Medicine (1991), 11 (6), 597-607CODEN: FRBMEH; ISSN:0891-5849.

One-electron redn. of diaziquone (AZQ) by purified rat liver NADPH cytochrome c reductase was assocd. with formation of AZQ semiquinone, superoxide anions, hydrogen peroxide, and hydroxyl radicals as indicated by ESR spin-trapping studies. Reactive oxygen formation correlated with AZQ-dependent prodn. of single and double PM2 plasmid DNA strand breaks mediated by this system as detected by gel electrophoresis. Direct two-electron redn. of AZQ by purified rat liver NAD(P)H (quinone acceptor) oxidoreductase (OAO) was also assocd. with formation of AZQ semiquinone, superoxide anions, hydrogen peroxide, and hydroxyl radicals as detected by ESR spin trapping. Furthermore, PM2 plasmid DNA strand breaks were detected in the presence of this system. Plasmid DNA strand breakage was inhibited by dicumarol (49 + 5%) catalase (57 ± 2.3%), SOD (42.2 ± 3.6%) and ethanol (41.1 ± 3.9%) showing QAO and reactive oxygen formation was involved in the PM2 plasmid DNA strand breaks obsd. These results show that both one- and two-electron enzymic redn. of AZQ give rise to formation of reactive oxygen species and DNA strand breaks. Autoxidn. of the AZQ semiquinone and hydroquinone in the presence of mol. oxygen appears to be responsible for these processes. QAO appears to be involved in the metabolic activation of AZQ to free radical species. The cellular levels and distribution of this enzyme may play an important role in the response of tumor and normal cells to this antitumor agent.

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479

Cortez, R. ; Luna-Vital, D. A. ; Margulis, D. ; Gonzalez de Mejia, E. Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications. Compr. Rev. Food Sci. Food Saf. 2017, 16 , 180– 198, DOI: 10.1111/1541-4337.12244

[Crossref], [PubMed], [CAS], Google Scholar

479

Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications

Cortez, Regina; Luna-Vital, Diego A.; Margulis, Daniel; Gonzalez de Mejia, Elvira

Comprehensive Reviews in Food Science and Food Safety (2017), 16 (1), 180-198CODEN: CRFSBJ; ISSN:1541-4337. (Institute of Food Technologists)

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480

Coultate, T. ; Blackburn, R. S. Food Colorants: Their Past, Present and Future. Color. Technol. 2018, 134 , 165– 186, DOI: 10.1111/cote.12334

[Crossref], [CAS], Google Scholar

480

Food colorants: their past, present and future

Coultate, Tom; Blackburn, Richard S.

Coloration Technology (2018), 134 (3), 165-186CODEN: CTOEAZ; ISSN:1472-3581. (Wiley-Blackwell)

Whether we are purchasing fresh vegetables from a market stall, ready meals from the supermarket, eating at home or in a five-star restaurant, we use color to tell us what to expect in terms of taste, nutrition and safety. This review considers the techniques that have, over the years, been employed to modify the color of our food, and the interactions of these techniques with issues of safety and nutrition. The demand for brightly colored food resulted in the incorporation of some questionable inorg. and org. chem. being used in food products. A limited no. of synthetic dyes are still used in food today, but health concerns and the consumer-driven demand for natural colorants has brought about a change in the way food is colored. The proliferation of products with labels that state they contain "No artificial colors" on supermarket shelves suggests that the future of azo dyes and their various derivs. is strictly limited. Nature produces an abundance of colors and many of these are extd. and used as natural food colorants; however, they are subject to application limitations and stability problems. Significant research by academia and industry into methods to stabilize and expand the application possibilities for the various approved natural food colorants is ongoing, but most developments that food color manufacturers proclaim are enhanced vehicles for delivering established natural pigments into food products.

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481

Khoo, H. E. ; Azlan, A. ; Tang, S. T. ; Lim, S. M. Anthocyanidins and Anthocyanins: Colored Pigments as Food, Pharmaceutical Ingredients, and the Potential Health Benefits. Food Nutr. Res. 2017, 61 , 1361779– 1361779, DOI: 10.1080/16546628.2017.1361779

[Crossref], [PubMed], [CAS], Google Scholar

481

Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

Khoo, Hock Eng; Azlan, Azrina; Tang, Sou Teng; Lim, See Meng

Food & Nutrition Research (2017), 61 (1), 1361779/1-1361779/21CODEN: FNROA3; ISSN:1654-661X. (Taylor & Francis Ltd.)

Anthocyanins are colored water-sol. pigments belonging to the phenolic group. The pigments are in glycosylated forms. Anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables. Berries, currants, grapes, and some tropical fruits have high anthocyanins content. Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins. Among the anthocyanin pigments, cyanidin-3-glucoside is the major anthocyanin found in most of the plants. The colored anthocyanin pigments have been traditionally used as a natural food colorant. The color and stability of these pigments are influenced by pH, light, temp., and structure. In acidic condition, anthocyanins appear as red but turn blue when the pH increases. Chromatog. has been largely applied in extn., sepn., and quantification of anthocyanins. Besides the use of anthocyanidins and anthocyanins as natural dyes, these colored pigments are potential pharmaceutical ingredients that give various beneficial health effects. Scientific studies, such as cell culture studies, animal models, and human clin. trials, show that anthocyanidins and anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurol. health, and protect against various non-communicable diseases. These studies confer the health effects of anthocyanidins and anthocyanins, which are due to their potent antioxidant properties. Different mechanisms and pathways are involved in the protective effects, including free-radical scavenging pathway, cyclooxygenase pathway, mitogen-activated protein kinase pathway, and inflammatory cytokines signaling. Therefore, this review focuses on the role of anthocyanidins and anthocyanins as natural food colorants and their nutraceutical properties for health.

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482

Shipp, J. ; Abdel-Aal, E.-S. M. Food Applications and Physiological Effects of Anthocyanins as Functional Food Ingredients. Open Food Sci. J. 2010, 4 , 7– 22, DOI: 10.2174/1874256401004010007

[Crossref], [CAS], Google Scholar

482

Food applications and physiological effects of anthocyanins as functional food ingredients

Shipp, Jaclyn; Abdel-Aal, El-Sayed M.

Open Food Science Journal (2010), 4 (), 7-22CODEN: OFSJA2; ISSN:1874-2564. (Bentham Science Publishers Ltd.)

A review. Anthocyanins have been suggested as promising dietary compds. with an important role in human health. They are the largest group of water-sol. pigments in the plants, which are responsible for the red, purple and blue hues evident in fruits, vegetables, flowers and grains. As natural compds. of vegetables, fruits and red wines, anthocyanins are estd. to be widely consumed by humans with the estd. daily intake about 12.5 mg/d in the United States. Interest in anthocyanin-rich foods and exts. has intensified recently because of their possible health benefits. Anthocyanins have been shown to be potent antioxidants as well as anti-diabetic, anti-carcinogenic and having ocular effects among others. Findings of their beneficial health effects support their role as natural food colorants, functional foods and dietary supplements. The present article summarizes our knowledge on the bioavailability, antioxidant activity and health-enhancing components of anthocyanin-rich foods and exts. In addn., their current and potential use as a natural food colorant, functional food and dietary supplement in the food and beverage industry is discussed.

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483

Eder, R. Pigments in Food Analysis by Hplc; Nollet, L. M. L. , Ed.; Marcel Dekker: New York, 2000.

484

Rose, P. M. ; Cantrill, V. ; Benohoud, M. ; Tidder, A. ; Rayner, C. M. ; Blackburn, R. S. Application of Anthocyanins from Blackcurrant (Ribes Nigrum L.) Fruit Waste as Renewable Hair Dyes. J. Agric. Food Chem. 2018, 66 , 6790– 6798, DOI: 10.1021/acs.jafc.8b01044

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484

Application of Anthocyanins from Blackcurrant (Ribes nigrum L.) Fruit Waste as Renewable Hair Dyes

Rose, Paul M.; Cantrill, Victoria; Benohoud, Meryem; Tidder, Alenka; Rayner, Christopher M.; Blackburn, Richard S.

Journal of Agricultural and Food Chemistry (2018), 66 (26), 6790-6798CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

There is much concern about the toxicol. effects of synthetic hair dyes. As an alternative approach, renewable waste blackcurrant (Ribes nigrum L.) fruit skins from the fruit pressing industry were extd. using acidified water with a solid-phase purifn. stage. Anthocyanin colorants were isolated in good yields (2-3% wt./wt.) and characterized by HPLC. Sorption of anthocyanins onto hair followed a Freundlich isotherm; anthocyanin-anthocyanin aggregation interactions enabled high buildup on the substrate. Sorption energy of cyanidin-3-O-glucoside (monosaccharide) > cyanidin-3-O-rutinoside (disaccharide), but sorption properties of different anthocyanin glucosides were very similar. Intense blue-colored dyeing on hair could be achieved with λmax-vis at 580 nm, typical of the anionic quinonoid base; it is suggested that hair provides an environment that enables the stabilization of the anionic quinonoid base on adsorption through assocn. with cations in the hair and copigmentation effects. Dyeings were stable to multiple washes.

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485

Chan, C. F. ; Lien, C. Y. I. ; Lai, Y. C. ; Huang, C. L. ; Liao, W. C. Influence of Purple Sweet Potato Extracts on the Uv Absorption Properties of a Cosmetic Cream. J. Cosmet. Sci. 2010, 61 , 333– 341

[PubMed], [CAS], Google Scholar

485

Influence of purple sweet potato extracts on the UV absorption properties of a cosmetic cream

Chan Chin-Feng; Lien Ching-Yi; Lai Yung-Chang; Huang Che-Lun; Liao Wayne C

Journal of cosmetic science (2010), 61 (5), 333-41 ISSN:1525-7886.

Anthocyanins were added to a cosmetic cream to provide additional protection against UV radiation. The influence of anthocyanins on UV absorption ability was carefully evaluated. Anthocyanins were successfully extracted from TNG73 purple sweet potato using acidic ethanol and acidic water. Acidic ethanol-extracted anthocyanins had better radical scavenging ability, higher total phenolic content, and stronger reducing ability than acidic water-extracted anthocyanins. The cosmetic cream with 0.61 mg of total anthocyanins (per 100 g cream) absorbed approximately 46% of the incident UV radiation. Although the anthocyanins absorbed both UV-A and UV-B radiation, they were particularly effective against UV-B rays. This study demonstrates that the addition of anthocyanin extracts of purple sweet potato to a cosmetic cream improves the cream's UV absorption ability.

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486

Gasparrini, M. ; Forbes-Hernandez, T. Y. ; Afrin, S. ; Reboredo-Rodriguez, P. ; Cianciosi, D. ; Mezzetti, B. ; Quiles, J. L. ; Bompadre, S. ; Battino, M. ; Giampieri, F. Strawberry-Based Cosmetic Formulations Protect Human Dermal Fibroblasts against Uva-Induced Damage. Nutrients 2017, 9 , 605, DOI: 10.3390/nu9060605

[Crossref], [CAS], Google Scholar

486

Strawberry-based cosmetic formulations protect human dermal fibroblasts against UVA-induced damage

Gasparrini, Massimiliano; Forbes-Hernandez, Tamara Y.; Afrin, Sadia; Reboredo-Rodriguez, Patricia; Cianciosi, Danila; Mezzetti, Bruno; Quiles, Jose L.; Bompadre, Stefano; Battino, Maurizio; Giampieri, Francesca

Nutrients (2017), 9 (6), 605/1-605/15CODEN: NUTRHU; ISSN:2072-6643. (MDPI AG)

Extreme exposure of skin to UV A (UVA)-radiation may induce a dysregulated prodn. of reactive oxygen species (ROS) which can interact with cellular biomols. leading to oxidative stress, inflammation, DNA damage, and alteration of cellular mol. pathways, responsible for skin photoaging, hyperplasia, erythema, and cancer. For these reasons, the use of dietary natural bioactive compds. with remarkable antioxidant activity could be a strategic tool to counteract these UVA-radiation-caused deleterious effects. Thus, the purpose of the present work was to test the efficacy of strawberry (50 μg/mL)-based formulations supplemented with Coenzyme Q10 (100 μg/mL) and sun protection factor 10 in human dermal fibroblasts irradiated with UVA-radiation. The apoptosis rate, the amt. of intracellular reactive oxygen species (ROS) prodn., the expression of proteins involved in antioxidant and inflammatory response, and mitochondrial functionality were evaluated. The results showed that the synergic topical use of strawberry and Coenzyme Q10 provided a significant (p < 0.05) photoprotective effect, reducing cell death and ROS, increasing antioxidant defense, lowering inflammatory markers, and improving mitochondrial functionality. The obtained results suggest the use of strawberry-based formulations as an innovative, natural, and useful tool for the prevention of UVA exposure-induced skin diseases in order to decrease or substitute the amt. of synthetic sunscreen agents.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitVersbnN&md5=a30af673b0eeca2a6c22183cc99a656f

487

Soto, M. L. ; Falqué, E. ; Domínguez, H. Relevance of Natural Phenolics from Grape and Derivative Products in the Formulation of Cosmetics. Cosmetics 2015, 2 , 259, DOI: 10.3390/cosmetics2030259

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487

Relevance of natural phenolics from grape and derivative products in the formulation of cosmetics

Soto, Maria Luisa; Falque, Elena; Dominguez, Herminia

Cosmetics (2015), 2 (3), 259-276CODEN: COSMCC; ISSN:2079-9284. (MDPI AG)

The consumer demand for natural ingredients in cosmetic products is increasing. Phenolic compds. are among the most studied natural antioxidant compds., they also present antimicrobial, anti-inflammatory or antiaging actions and can permeate through the skin barrier. Grapes contain valuable phenolic components and grape byproducts are widely available low cost raw materials. This review presents an overview of the application of phenolic compds. from grape products and byproducts as sources of natural ingredients for cosmetics.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVyiu7jF&md5=f0b3c5ed0a803f093381e1d72f836e59

488

McGhie, T. K. ; Walton, M. C. The Bioavailability and Absorption of Anthocyanins: Towards a Better Understanding. Mol. Nutr. Food Res. 2007, 51 , 702– 713, DOI: 10.1002/mnfr.200700092

[Crossref], [PubMed], [CAS], Google Scholar

488

The bioavailability and absorption of anthocyanins: Towards a better understanding

McGhie, Tony K.; Walton, Michaela C.

Molecular Nutrition & Food Research (2007), 51 (6), 702-713CODEN: MNFRCV; ISSN:1613-4125. (Wiley-VCH Verlag GmbH & Co. KGaA)

A review. Evidence that anthocyanins have beneficial effects for health are increasingly being reported in the scientific literature and these compds. are now widely recognized as potential therapeutic compds. Berry fruit are rich sources of anthocyanins and berry fruit products or derived beverages can provide tens to hundreds of milligrams of anthocyanins in a single serve. Anthocyanins exhibit complex chem. behaviors in vitro and this will result in complex behavior in vivo. This review attempts to summarize some aspects of anthocyanin biochem. and discusses these in the context of what is currently known about bioavailability and absorption. Compared with other flavonoid groups, such as flavonols, relatively little is known about the details and mechanisms of anthocyanin absorption and transport and much remains to be discovered.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXmvFamsrg%253D&md5=f3ed1996ad444124acba04ac6320bf32

489

Zhang, Y. ; Seeram, N. P. ; Lee, R. ; Feng, L. ; Heber, D. Isolation and Identification of Strawberry Phenolics with Antioxidant and Human Cancer Cell Antiproliferative Properties. J. Agric. Food Chem. 2008, 56 , 670– 675, DOI: 10.1021/jf071989c

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489

Isolation and Identification of Strawberry Phenolics with Antioxidant and Human Cancer Cell Antiproliferative Properties

Zhang, Yanjun; Seeram, Navindra P.; Lee, Rupo; Feng, Lydia; Heber, David

Journal of Agricultural and Food Chemistry (2008), 56 (3), 670-675CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Studies suggest that consumption of berry fruits, including strawberries (Fragaria × ananassa Duch.), may have beneficial effects against oxidative stress mediated diseases such as cancer. Berries contain multiple phenolic compds., which are thought to contribute to their biol. properties. Comprehensive profiling of phenolics from strawberries was previously reported using high-performance liq. chromatog. with mass spectrometry (HPLC-MS) detection. The current study reports the isolation and structural characterization of 10 phenolic compds. from strawberry exts. using a combination of Amberlite XAD16-resin and C18 columns, HPLC-UV, and NMR (NMR) spectroscopy methods. The phenolics were cyanidin 3-glucoside (1), pelargonidin (2), pelargonidin 3-glucoside (3), pelargonidin 3-rutinoside (4), kaempferol (5), quercetin (6), kaempferol 3-(6-coumaroylglucoside) (7), 3,4,5-trihydroxyphenylacrylic acid (8), glucose ester of (E)-p-coumaric acid (9), and ellagic acid. Strawberry crude exts. and purified compds. 1-10 were evaluated for antioxidant and human cancer cell antiproliferative activities by the Trolox equiv. antioxidant capacity (TEAC) and luminescent ATP cell viability assays, resp. Among the pure compds., the anthocyanins 1 (7156 μM Trolox/mg), 2 (4922 μM Trolox/mg), and 4 (5514 μM Trolox/mg) were the most potent antioxidants. Crude exts. (250 μg/mL) and pure compds. (100 μg/mL) inhibited the growth of human oral (CAL-27, KB), colon (HT29, HCT-116), and prostate (LNCaP, DU145) cancer cells with different sensitivities obsd. between cell lines. This study adds to the growing body of data supporting the bioactivities of berry fruit phenolics and their potential impact on human health.

https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptlyrtg%253D%253D&md5=06577767b9a432cd952380d1f58db884

490

Jing, P. ; Bomser, J. A. ; Schwartz, S. J. ; He, J. ; Magnuson, B. A. ; Giusti, M. M. Structure–Function Relationships of Anthocyanins from Various Anthocyanin-Rich Extracts on the Inhibition of Colon Cancer Cell Growth. J. Agric. Food Chem. 2008, 56 , 9391– 9398, DOI: 10.1021/jf8005917

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490

Structure-Function Relationships of Anthocyanins from Various Anthocyanin-Rich Extracts on the Inhibition of Colon Cancer Cell Growth

Jing, Pu; Bomser, Joshua A.; Schwartz, Steven J.; He, Jian; Magnuson, Bernadene A.; Giusti, M. Monica

Journal of Agricultural and Food Chemistry (2008), 56 (20), 9391-9398CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

Anthocyanins are potent antioxidants and may be chemoprotective. However, the structure-function relationships are not well understood. The objectives of this study were to compare the chemoprotective properties of anthocyanin-rich exts. (AREs) with variable anthocyanin profiles to understand the relationship between anthocyanin chem. structure and chemoprotective activity, measured as inhibition of colon cancer cell proliferation. Addnl., the chemoprotective interaction of anthocyanins and other phenolics was investigated. AREs with different anthocyanin profiles from purple corn, chokeberry, bilberry, purple carrot, grape, radish, and elderberry were tested for growth inhibition (GI50) using a human colorectal adenocarcinoma (HT29) cell line. All AREs suppressed HT29 cell growth to various degrees as follows: purple corn (GI50 ∼ 14 μg of cy-3-glu equiv/mL) > chokeberry and bilberry > purple carrot and grape > radish and elderberry (GI50 > 100 μg of cy-3-glu equiv/mL). Anthocyanins played a major role in AREs' chemoprotection and exerted an additive interaction with the other phenolics present. Statistical analyses suggested that anthocyanin chem. structure affected chemoprotection, with nonacylated monoglycosylated anthocyanins having greater inhibitory effect on HT-29 cell proliferation, whereas anthocyanins with pelargonidin, triglycoside, and/or acylation with cinnamic acid exerted the least effect. These findings should be considered for crop selection and the development of anthocyanin-rich functional foods.

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491

Wang, H. ; Nair, M. G. ; Strasburg, G. M. ; Chang, Y.-C. ; Booren, A. M. ; Gray, J. I. ; DeWitt, D. L. Antioxidant and Antiinflammatory Activities of Anthocyanins and Their Aglycon, Cyanidin, from Tart Cherries. J. Nat. Prod. 1999, 62 , 294– 296, DOI: 10.1021/np980501m

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491

Antioxidant and Antiinflammatory Activities of Anthocyanins and Their Aglycon, Cyanidin, from Tart Cherries

Wang, Haibo; Nair, Muraleedharan G.; Strasburg, Gale M.; Chang, Yu-Chen; Booren, Alden M.; Gray, J. Ian; DeWitt, David L.

Journal of Natural Products (1999), 62 (2), 294-296CODEN: JNPRDF; ISSN:0163-3864. (American Chemical Society)

The anthocyanins (1-3) and cyanidin isolated from tart cherries exhibited in vitro antioxidant and antiinflammatory activities comparable to com. products. The inhibition of lipid peroxidn. of anthocyanins 1-3 and their aglycon, cyanidin, were 39, 70, 75, and 57%, resp., at 2-mM concns. The antioxidant activities of 1-3 and cyanidin were comparable to the antioxidant activities of tert-butylhydroquinone and butylated hydroxytoluene and superior to vitamin E at 2-mM concns. In the antiinflammatory assay, cyanidin gave IC50 values of 90 and 60 mM, resp., for prostaglandin H endoperoxide synthase-1 and prostaglandin H endoperoxide synthase-2 enzymes.

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492

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492

Application of Anthocyanins from Blackcurrant (Ribes nigrum L.) Fruit Waste as Renewable Hair Dyes

Rose, Paul M.; Cantrill, Victoria; Benohoud, Meryem; Tidder, Alenka; Rayner, Christopher M.; Blackburn, Richard S.

Journal of Agricultural and Food Chemistry (2018), 66 (26), 6790-6798CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)

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493

Westfall, A. ; Giusti, M. M. Color Profiles and Stability of Acylated and Nonacylated Anthocyanins as Novel Pigment Sources in a Lipstick Model: A Viable Alternative to Synthetic Colorants. J. Cosmet. Sci. 2017, 68 , 233– 244

494

Westfall, A. ; Sigurdson, G. T. ; Giusti, M. M. Antioxidant, UV Protection, and Antiphotoaging Properties of Anthocyanin-Pigmented Lipstick Formulations. J. Cosmet. Sci. 2019, 70 , 63– 76

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Source: https://pubs.acs.org/doi/10.1021/acs.chemrev.1c00399

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Click in the Answer Box to Activate the Palette. Write the Ka Expression for Hcn in Water.

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