Articles de revues : « Flavan-3-ol monomer »

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Vogiatzoglou, Anna, Angela A. Mulligan, Robert N. Luben, Marleen A. H. Lentjes, Christian Heiss, Malte Kelm, Marc W. Merx, Jeremy P. E. Spencer, Hagen Schroeter et Gunter G. C. Kuhnle. « Assessment of the dietary intake of total flavan-3-ols, monomeric flavan-3-ols, proanthocyanidins and theaflavins in the European Union ». British Journal of Nutrition 111, n^o 8 (13 décembre 2013) : 1463–73. http://dx.doi.org/10.1017/s0007114513003930.

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Dietary interventions with flavan-3-ols have shown beneficial effects on vascular function. The translation of these findings into the context of the health of the general public requires detailed information on habitual dietary intake. However, only limited data are currently available for European populations. Therefore, in the present study, we assessed the habitual intake of flavan-3-ol monomers, proanthocyanidins (PA) and theaflavins in the European Union (EU) and determined their main food sources using the EFSA (European Food Safety Authority) Comprehensive European Food Consumption Database. Data for adults aged 18–64 years were available from fourteen European countries, and intake was determined using the FLAVIOLA Flavanol Food Composition Database, developed for the present study and based on the latest US Department of Agriculture and Phenol-Explorer databases. The mean habitual intake of flavan-3-ol monomers, theaflavins and PA ranged from 181 mg/d (Czech Republic) to 793 mg/d (Ireland). The highest intakes of flavan-3-ol monomers and theaflavins were observed in Ireland (191/505 mg/d) and the lowest intakes in Spain (24/9 mg/d). In contrast, the daily intake of PA was highest in Spain (175 mg/d) and lowest in The Netherlands (96 mg/d). Main sources were tea (62 %), pome fruits (11 %), berries (3 %) and cocoa products (3 %). Tea was the major single contributor to monomer intake (75 %), followed by pome fruits (6 %). Pome fruits were also the main source of PA (28 %). The present study provides important data on the population-based intake of flavanols in the EU and demonstrates that dietary intake amounts for flavan-3-ol monomers, PA and theaflavins vary significantly across European countries. The average habitual intake of flavan-3-ols is considerably below the amounts used in most dietary intervention studies.

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Raman, Gowri, Esther E. Avendano, Siyu Chen, Jiaqi Wang, Julia Matson, Bridget Gayer, Janet A. Novotny et Aedín Cassidy. « Dietary intakes of flavan-3-ols and cardiometabolic health : systematic review and meta-analysis of randomized trials and prospective cohort studies ». American Journal of Clinical Nutrition 110, n^o 5 (26 août 2019) : 1067–78. http://dx.doi.org/10.1093/ajcn/nqz178.

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ABSTRACT Background Although available data suggest that some dietary flavan-3-ol sources reduce cardiometabolic risk, to our knowledge no review has systematically synthesized their specific contribution. Objective We aimed to examine, for the first time, if there is consistent evidence that higher flavan-3-ol intake, irrespective of dietary source, reduces cardiometabolic risk. Methods MEDLINE, Cochrane Central, and Commonwealth Agricultural Bureau abstracts were searched for prospective cohorts and randomized controlled trials (RCTs) published from 1946 to March 2019 on flavan-3-ol intake and cardiovascular disease (CVD) risk. Random-effects models meta-analysis was used. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach assessed the strength of evidence. Results Of 15 prospective cohorts (23 publications), 4 found highest compared with lowest habitual intakes of flavan-3-ols were associated with a 13% reduction in risk of CVD mortality and 2 found a 19% reduction in risk of chronic heart disease (CHD) incidence. Highest compared with lowest habitual intakes of monomers were associated with a reduction in risk of type 2 diabetes mellitus (T2DM) (n = 5) and stroke (n = 4) (10% and 18%, respectively). No association was found for hypertension. Of 156 RCTs, flavan-3-ol intervention resulted in significant improvements in acute/chronic flow-mediated dilation (FMD), systolic (SBP) and diastolic blood pressure (DBP), total cholesterol (TC), LDL and HDL cholesterol, triglycerides (TGs), hemoglobin A1c (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR). All analyses, except HbA1c, were associated with moderate/high heterogeneity. When analyses were limited to good methodological quality studies, improvements in TC, HDL cholesterol, SBP, DBP, HOMA-IR, and acute/chronic FMD remained significant. In GRADE evaluations, there was moderate evidence in cohort studies that flavan-3-ol and monomer intakes were associated with reduced risk of CVD mortality, CHD, stroke, and T2DM, whereas RCTs reported improved TC, HDL cholesterol, SBP, and HOMA-IR. Conclusions Available evidence supports a beneficial effect of flavan-3-ol intake on cardiometabolic outcomes, but there was considerable heterogeneity in the meta-analysis. Future research should focus on an integrated intake/biomarker approach in cohorts and high-quality dose–response RCTs. This review was registered at www.crd.york.ac.uk/PROSPERO/ as CRD42018035782.

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Knaze, Viktoria, Raul Zamora-Ros, Leila Luján-Barroso, Isabelle Romieu, Augustin Scalbert, Nadia Slimani, Elio Riboli et al. « Intake estimation of total and individual flavan-3-ols, proanthocyanidins and theaflavins, their food sources and determinants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study ». British Journal of Nutrition 108, n^o 6 (20 décembre 2011) : 1095–108. http://dx.doi.org/10.1017/s0007114511006386.

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Epidemiological studies suggest health-protective effects of flavan-3-ols and their derived compounds on chronic diseases. The present study aimed to estimate dietary flavan-3-ol, proanthocyanidin (PA) and theaflavin intakes, their food sources and potential determinants in the European Prospective Investigation into Cancer and Nutrition (EPIC) calibration cohort. Dietary data were collected using a standardised 24 h dietary recall software administered to 36 037 subjects aged 35–74 years. Dietary data were linked with a flavanoid food composition database compiled from the latest US Department of Agriculture and Phenol-Explorer databases and expanded to include recipes, estimations and retention factors. Total flavan-3-ol intake was the highest in UK Health-conscious men (453·6 mg/d) and women of UK General population (377·6 mg/d), while the intake was the lowest in Greece (men: 160·5 mg/d; women: 124·8 mg/d). Monomer intake was the highest in UK General population (men: 213·5 mg/d; women: 178·6 mg/d) and the lowest in Greece (men: 26·6 mg/d in men; women: 20·7 mg/d). Theaflavin intake was the highest in UK General population (men: 29·3 mg/d; women: 25·3 mg/d) and close to zero in Greece and Spain. PA intake was the highest in Asturias (men: 455·2 mg/d) and San Sebastian (women: 253 mg/d), while being the lowest in Greece (men: 134·6 mg/d; women: 101·0 mg/d). Except for the UK, non-citrus fruits (apples/pears) were the highest contributors to the total flavan-3-ol intake. Tea was the main contributor of total flavan-3-ols in the UK. Flavan-3-ol, PA and theaflavin intakes were significantly different among all assessed groups. This study showed heterogeneity in flavan-3-ol, PA and theaflavin intake throughout the EPIC countries.

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Alcaraz, Miguel, Amparo Olivares, Daniel Gyingiri Achel, José Antonio García-Gamuz, Julián Castillo et Miguel Alcaraz-Saura. « Genoprotective Effect of Some Flavonoids against Genotoxic Damage Induced by X-rays In Vivo : Relationship between Structure and Activity ». Antioxidants 11, n^o 1 (30 décembre 2021) : 94. http://dx.doi.org/10.3390/antiox11010094.

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Flavonoids constitute a group of polyphenolic compounds characterized by a common gamma-benzo- pyrone structure considered in numerous biological systems to possess antioxidant capacity. Among the different applications of flavonoids, its genoprotective capacity against damage induced by ionizing radiation stands out, which has been related to antioxidant activity and its chemical structure. In this study, we determined the frequency of appearance of micronucleus in vivo by means of the micronucleus assay. This was conducted in mice treated with different flavonoids before and after exposure to 470 mGy X-rays; thereafter, their bone marrow polychromatophilic erythrocytes were evaluated to establish the structural factors enhancing the observed genoprotective effect. Our results in vivo show that the presence of a monomeric flavan-3-ol type structure, with absence of carbonyl group in position C4 of ring C, absence of conjugation between the carbons bearing the C2 = C3 double bond and the said ring, presence of a catechol group in ring B and characteristic hydroxylation in positions 5 and 7 of ring A are the structural characteristics that determine the highest degree of genoprotection. Additionally, a certain degree of polymerization of this flavonoid monomer, but maintaining significant levels of monomers and dimers, contributes to increasing the degree of genoprotection in the animals studied at both times of their administration (before and after exposure to X-rays).

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Liang, Changmei, Jianyong Guo, Mingxiang Chen, Xuehui Zhang, Guorong Zhang, Pengfei Zhang, Jinjun Liang et Pengfei Wen. « VvMYBPA2 Regulated the Accumulation of Flavan-3-ols though Forming a Trimeric Complex in ‘Zaoheibao’ Grape ». Agriculture 12, n^o 9 (7 septembre 2022) : 1414. http://dx.doi.org/10.3390/agriculture12091414.

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Flavan-3-ols are monomers of Proanthocyanidins (PAs), which are important polyphenolic compounds in grapes. Previous studies had shown that VvMYBPA2 was closely related to grape flavan-3-ol monomers biosynthesis, but its regulatory network is still unclear. Here, we found that the contents of (+)-catechin and (−)-epicatechin, the enzyme activities of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) and the expression of VvANR and VvLAR1 were increased in the VvMYBPA2 overexpression grape leaves compared to the control. It was proved that VvMYBPA2 protein interacted with VvWDR1 and VvWDR1 protein interacted with VvMYC2 by yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC). The promoters of VvANR and VvLAR1 were bound by VvMYBPA2 using yeast one-hybrid (Y1H) assay. These results suggested that VvMYBPA2 could form a trimeric complex with VvWDR1 and VvMYC2 and jointly regulated the expression of flavan-3-ol monomers related genes VvANR and VvLAR1, thereby affecting the enzyme activities of ANR and LAR and ultimately regulating the contents of flavan-3-ols.

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Almanza-Aguilera, Enrique, Daniela Ceballos-Sánchez, David Achaintre, Joseph A. Rothwell, Nasser Laouali, Gianluca Severi, Verena Katzke et al. « Urinary Concentrations of (+)-Catechin and (-)-Epicatechin as Biomarkers of Dietary Intake of Flavan-3-ols in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study ». Nutrients 13, n^o 11 (20 novembre 2021) : 4157. http://dx.doi.org/10.3390/nu13114157.

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This study examines the correlation of acute and habitual dietary intake of flavan-3-ol monomers, proanthocyanidins, theaflavins, and their main food sources with the urinary concentrations of (+)-catechin and (-)-epicatechin in the European Prospective Investigation into Cancer and Nutrition study (EPIC). Participants (N = 419, men and women) provided 24-h urine samples and completed a 24-h dietary recall (24-HDR) on the same day. Acute and habitual dietary data were collected using a standardized 24-HDR software and a validated dietary questionnaire, respectively. Intake of flavan-3-ols was estimated using the Phenol-Explorer database. Concentrations of (+)-catechin and (-)-epicatechin in 24-h urine were analyzed using tandem mass spectrometry after enzymatic deconjugation. Simple and partial Spearman’s correlations showed that urinary concentrations of (+)-catechin, (-)-epicatechin and their sum were more strongly correlated with acute than with habitual intake of individual and total monomers (acute rpartial = 0.13–0.54, p < 0.05; and habitual rpartial = 0.14–0.28, p < 0.01), proanthocyanidins (acute rpartial = 0.24–0.49, p < 0.001; and habitual rpartial = 0.10–0.15, p < 0.05), theaflavins (acute rpartial = 0.22–0.31, p < 0.001; and habitual rpartial = 0.20–0.26, p < 0.01), and total flavan-3-ols (acute rpartial = 0.40–0.48, p < 0.001; and habitual rpartial = 0.23–0.33, p < 0.001). Similarly, urinary concentrations of flavan-3-ols were weakly correlated with both acute (rpartial = 0.12–0.30, p < 0.05) and habitual intake (rpartial = 0.10–0.27, p < 0.05) of apple and pear, stone fruits, berries, chocolate and chocolate products, cakes and pastries, tea, herbal tea, wine, red wine, and beer and cider. Moreover, all comparable correlations were stronger for urinary (-)-epicatechin than for (+)-catechin. In conclusion, our data support the use of urinary concentrations of (+)-catechin and (-)-epicatechin, especially as short-term nutritional biomarkers of dietary catechin, epicatechin and total flavan-3-ol monomers.

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Noreljaleel, Anwar E. M., Anke Wilhelm et Susan L. Bonnet. « Analysis of Commercial Proanthocyanidins. Part 6 : Sulfitation of Flavan-3-Ols Catechin and Epicatechin, and Procyanidin B-3 ». Molecules 25, n^o 21 (28 octobre 2020) : 4980. http://dx.doi.org/10.3390/molecules25214980.

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Proanthocyanidins (PACs) are natural plant-derived polymers consisting of flavan-3-ol monomers. Quebracho (Schinopsis lorentzii and balansae) heartwood and mimosa (Acacia mearnsii) bark extracts are the major industrial sources of PACs. These commercial extracts are often sulfited to reduce their viscosity and increase their solubility in water. The chemical process of sulfitation is still poorly understood regarding stereochemical influences during the reaction and during the cleavage of the interflavanyl bond of oligomers. To gain a better understanding of sulfitation, two diastereomeric flavan-3-ol monomers were sulfited under industrial conditions, and procyanidin B-3 (catechin-4α→8-catechin) were sulfited to investigate interflavanyl bond cleavage with sulfitation at C-4. Treatment of diastereomeric flavan-3-ols 2R,3S-catechin and 2R,3R-epicatechin with NaHSO3 at 100 °C in aqueous medium afforded the enantiomeric (1R,2S)- and (1S,2R)-1-(3,4-dihydroxyphenyl)-2-hydroxy-3-(2,4,6-trihydroxyphenyl)propane-1-sulfonic acid, respectively. Utilizing computational NMR PD4 calculations it was determined that the direction of stereoselective nucleophilic attack is controlled by the C-3 configuration of the flavan-3-ols catechin and epicatechin. Sulfitation of the catechin-4α→8-catechin dimer 7 (procyanidin B-3) under the same conditions led to the cleavage of the interflavanyl bond yielding the C-4 sulfonic acid substituted catechin momomer. From the heterocyclic ring coupling constants it was determined that nucleophilic attack occurs from the β-face of the dimer leading to the 2,3-trans-3,4-cis isomer as product.

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Peleg, Hanna, Karine Gacon, Pascal Schlich et Ann C. Noble. « Bitterness and astringency of flavan-3-ol monomers, dimers and trimers ». Journal of the Science of Food and Agriculture 79, n^o 8 (juin 1999) : 1123–28. http://dx.doi.org/10.1002/(sici)1097-0010(199906)79:8<1123 ::aid-jsfa336>3.0.co;2-d.

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Tsang, Catherine, Cyril Auger, William Mullen, Aurélie Bornet, Jean-Max Rouanet, Alan Crozier et Pierre-Louis Teissedre. « The absorption, metabolism and excretion of flavan-3-ols and procyanidins following the ingestion of a grape seed extract by rats ». British Journal of Nutrition 94, n^o 2 (août 2005) : 170–81. http://dx.doi.org/10.1079/bjn20051480.

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Rats were fed a grape seed extract (GSE) containing (+)-catechin, (−)-epicatechin and dimers, trimers, tetramers and polymeric procyanidins. Liver, kidney, brain and gastrointestinal (GI) tract together with plasma, urine and faeces were collected over a 24 h period and their flavan-3-ol content was analysed by HPLC with tandem mass spectrometry and diode array detection. Small amounts of the GSE flavan-3-ols moved out of the stomach and into the duodenum/jejunum, and to a greater extent the ileum 1 h after ingestion, and into the caecum after 2 h with relatively small amounts being detected in the colon after 3 h. The GI tract contained the parent GSE flavan-3-ols and procyanidins with only trace amounts of metabolites and there were no indications that proanthocyanidins were depolymerised in the GI tract releasing monomeric flavan-3-ols. Plasma contained exclusively catechin glucuronides and methylated glucuronide metabolites which were also detected in the liver and kidneys. These metabolites were also present in urine together with sulphated metabolites and low amounts of the procyanidin dimers B1, B2, B3 and B4 as well as the trimer C2 and an unknown GSE trimer. The amounts of (+)-catechin and (−)-epicatechin metabolites excreted in urine relative to the quantity of the monomers ingested were 27 and 36 %, respectively, after 24 h. This is similar to the levels of urinary excretion reported to occur by other investigators after feeding (−)-epicatechin to rats and provides further, albeit indirect, evidence that the procyanidin oligomers in the GSE were not depolymerised to monomers to any extent after ingestion. No convincing analytical data were obtained for the presence of flavan-3-ol metabolites in the brain.

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Enomoto, Hirofumi, Senji Takahashi, Shiro Takeda et Hajime Hatta. « Distribution of Flavan-3-ol Species in Ripe Strawberry Fruit Revealed by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging ». Molecules 25, n^o 1 (26 décembre 2019) : 103. http://dx.doi.org/10.3390/molecules25010103.

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Flavan-3-ols, which comprise proanthocyanidins and their monomers, are major flavonoids in strawberries, and they have a wide range of biological activities and health benefits. However, their spatial distribution in strawberry fruit remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI), to visualize flavan-3-ols in ripe strawberry fruit. Peaks matching the m/z values of flavan-3-ols [M − H]− ions were detected in the negative ion mode using 1,5-diaminonaphthalene as matrix. Catechin and/or epicatechin, three B-type procyanidins, and two B-type propelargonidins were identified by MALDI-tandem MS. These flavan-3-ols were mainly distributed in the calyx, in and around the vascular bundles, and in the skin. In-source fragmentation of proanthocyanidins was determined using their standards, suggesting their distribution was mixed ion images of themselves, and fragment ions generated from those had a higher degree of polymerization. B-type procyanidins were predominantly distributed in the vascular bundles than in the skin, whereas B-type propelargonidins were almost equally distributed between the vascular bundles and skin, suggesting that their distribution patterns are different from the type of their flavan-3-ol monomers. Flavan-3-ols, especially B-type procyanidins, may help prevent pathogen infection not only in the skin but also in and around the vascular bundles.

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Radi, M., M. Mahrouz, A. Jaouad, M. Tacchini, S. Aubert, M. Hugues et M. J. Amiot. « Phenolic Composition, Browning Susceptibility, and Carotenoid Content of Several Apricot Cultivars at Maturity ». HortScience 32, n^o 6 (octobre 1997) : 1087–91. http://dx.doi.org/10.21273/hortsci.32.6.1087.

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Phenolic composition and susceptibility to browning were determined for nine apricot (Prunus armeniaca L.) cultivars. Chlorogenic and neochlorogenic acids, (+)-catechin and (-)-epicatechin, and rutin (or quercetin-3-rutinoside) were the major phenolic compounds in apricots. In addition to these compounds, other quercetin-3-glycosides and procyanidins have been detected. Chlorogenic acid content decreased rapidly during enzymatic browning, but the susceptibility to browning seemed to be more strongly correlated with the initial amount of flavan-3-ols (defined as catechin monomers and procyanidins). As chlorogenic acid is certainly the best substrate for polyphenol oxidase, the development of brown pigments depended mainly on the flavan-3-ol content.

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Enomoto, Hirofumi, et Takashi Nirasawa. « Localization of Flavan-3-ol Species in Peanut Testa by Mass Spectrometry Imaging ». Molecules 25, n^o 10 (20 mai 2020) : 2373. http://dx.doi.org/10.3390/molecules25102373.

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Flavan-3-ols, procyanidins and their monomers are major flavonoids present in peanuts that show a wide range of biological properties and health benefits, based on their potent antioxidant activity. Procyanidin oligomers, especially A-type, are reportedly abundant in peanut skin; however, their localization in the raw peanut testa remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to investigate the localization of flavan-3-ols in peanut testa. 1,5-Diaminonaphthalene was coated onto the peanut section by matrix vapor deposition/recrystallization, and MALDI-MSI measurements were performed in the negative-ion mode. Peaks matching the m/z values of flavan-3-ol [M − H]− ions were observed in the mass spectrum extracted from the outer epidermis of the peanut testa, using the region of interest function. Catechin and/or epicatechin, five A-type, and one B-type procyanidins were assigned by the fragment ions generated by retro-Diels-Alder, heterocyclic ring fission, and quinone methide reactions detected in MALDI-tandem MS spectra. These flavan-3-ols were localized in the outer epidermis of the peanut testa. This information will contribute to improving the extraction and purification efficiencies of flavan-3-ols from peanut testa. As flavan-3-ols display anti-microbial activity, it is speculated that flavan-3-ols present in the outer epidermis of peanut testa act to prevent pathogen infection.

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Gacon, Karine, Hanna Peleg et Ann C. Noble. « II-29. Bitterness and astringency of flavan-3-OL monomers, dimers and trimers ». Food Quality and Preference 7, n^o 3-4 (juillet 1996) : 343–44. http://dx.doi.org/10.1016/s0950-3293(96)90245-1.

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Chen, Mingshun, et Shujuan Yu. « Characterization of Lipophilized Monomeric and Oligomeric Grape Seed Flavan-3-ol Derivatives ». Journal of Agricultural and Food Chemistry 65, n^o 40 (29 septembre 2017) : 8875–83. http://dx.doi.org/10.1021/acs.jafc.7b03530.

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Godjevac, Dejan, Vele Tesevic, Milovan Velickovic, Ljubodrag Vujisic, Vlatka Vajs et Slobodan Milosavljevic. « Polyphenolic compounds in seeds from some grape cultivars grown in Serbia ». Journal of the Serbian Chemical Society 75, n^o 12 (2010) : 1641–52. http://dx.doi.org/10.2298/jsc100519131g.

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Seed extracts from eight grape cultivars (Vitis vinifera) growing in Serbia were screened for their polyphenolic composition by means of HPLC/PDA/ESI/MS analysis. The study revealed 34 phenolic compounds belonging to the following groups: flavan-3-ol monomers, proanthocyanidins, flavonols, hydroxycinnamic acids and hydroxybenzoic acid derivatives. The quantities of the main constituents were determined using PDA/HPLC. Qualitative and quantitative differences among the cultivars were observed.

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Simon, Margaux, et Sonia Collin. « Why Oxidation Should Be Still More Feared in NABLABs : Fate of Polyphenols and Bitter Compounds ». Beverages 8, n^o 4 (4 octobre 2022) : 61. http://dx.doi.org/10.3390/beverages8040061.

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Nowadays, non-alcoholic (NAB) and low-alcoholic beers (LAB) still significantly suffer from staling defects when fresh, partially due to absence of ethanol as antioxidant. In the current work, the fate of flavan-3-ols (monomers, dimers, and trimers) and bitter compounds (isohumulones, humulinones, etc.) of 11 commercial NABLABs available on the Belgian market was monitored through one year of aging at 20 °C in the dark. Fresh NABLABs contained variable flavan-3-ols and bitter compounds levels (between 3.0–10.0 mg/L and 8.0–39.0 mg/L, respectively), depending on different technological processes used. Chill haze and color were also investigated as potential oxidation markers of fresh and aged beers. Surprisingly, contrary to conventional beers, the oligomers’ concentration (dimer and trimer procyanidins) exhibited a strong correlation (R2 = 0.95) with chill haze before aging, suggesting prematured oxidation of the samples. After a year of storage, significant degradation occurred as for regular dry hopped beers (process very sensitive to oxidation), only 27% remaining for flavan-3-ol dimers and an average 16% for trans-isohumulones. Oxidation risk appears here as the main weakness of NABLABs, which could be probably improved by spiking very efficient antioxidants.

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Nieto, Juan Antonio, Susana Santoyo, Marin Prodanov, Guillermo Reglero et Laura Jaime. « Valorisation of Grape Stems as a Source of Phenolic Antioxidants by Using a Sustainable Extraction Methodology ». Foods 9, n^o 5 (8 mai 2020) : 604. http://dx.doi.org/10.3390/foods9050604.

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Pressurized liquid extraction with ethanol:water mixtures was proposed for obtaining phenolic antioxidants from grape stems. The optimal extraction conditions were elucidated by using a central composite rotatable design (solvent (X1, 0–100% ethanol:water v/v), temperature (X2, 40–120 °C) and time (X3, 1–11 min)). Response surface methodology determined 30% ethanol:water, 120 °C and 10 min as the optimal extraction conditions regarding total phenolic content (TPC) (185.3 ± 2.9 mg gallic acid/g of extract) and antioxidant activity (3.55 ± 0.21 mmol Trolox/g, 1.22 ± 0.06 mmol Trolox/g and 1.48 ± 0.17 mmol Trolox/g of extract in ABTS, DPPH and ORAC methodologies, respectively). The antioxidant activity was attributed to total polymer procyanidins and flavan-3-ol monomers and oligomers, although other phenolic compound contributions should not be ruled out. Forty-two phenolic compounds were identified in the optimal extract, mainly polymer procyanidins and, to a lesser extent, monomers and oligomers of flavan-3-ols, quercetin-3-O-glucuronide, ε-viniferin, gallic and caftaric acid. Ethyl gallate, ellagic acid, protocatechuic aldehyde, delphinidin-7-O-glucoside and cyanidin-3-O-glucoside were reported for the first time in grape stem extracts. In conclusion, this study highlights the use of this winery side stream as a source of antioxidants within a sustainable food system.

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Kyraleou, Maria, Stamatina Kallithraka, Stefanos Koundouras, Kleopatra Chira, Serkos Haroutounian, Hariklia Spinthiropoulou et Yorgos Kotseridis. « Effect of vine training system on the phenolic composition of red grapes (Vitis vinifera L. cv. Xinomavro) ». OENO One 49, n^o 1 (31 mars 2015) : 71. http://dx.doi.org/10.20870/oeno-one.2015.49.2.92.

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Aims: In order to investigate the effect of vine training system on grape phenolic composition, a divided canopy system (Lyre) and a vertical shoot positioned trellis with two different pruning systems (Royat and Guyot) were applied in a commercial vineyard of cv. Xinomavro (Vitis vinifera L.). The quality of the produced grapes was determined with respect to three analytical parameters: anthocyanin content, tannin composition and proanthocyanidin structure.Methods and results: Monomeric anthocyanins, flavan-3-ol monomers and oligomers, tannin mean degree of polymerization (mDP), galloylation percentage (%G), and extension and terminal subunit structure were determined in seeds and skins by HPLC and LC/MS. Total phenolics, anthocyanin content, tannin concentration and antioxidant activity were measured in whole berries. Grapes and wines of the Lyre system were characterized by increased concentration of total and individual anthocyanins and total phenols. Individual flavan-3-ol monomers and oligomers were highest in Royat grape skins and Guyot seeds. Concerning proanthocyanidin structure, Royat grapes had significantly higher mDP and lower %G in skin and seed polymeric tannin fractions, compared to the other two systems, possibly leading to a lower grape astringency potential.Conclusion: Training system may affect grape anthocyanin concentration, total flavan-3-ol content as well as skin and seed proanthocyanidin structure (mDP, %G, extension and terminal subunits).Significance and impact of the study: The results of the present study could be of high importance to both grape growers and winemakers. Xinomavro grapes are rather poor in anthocyanins while being characterized by dry and astringent tannins. By adopting Lyre as a training system, higher anthocyanin contents could be achieved in grapes, resulting in wines with more attractive colour when adopting a longer pre-fermentation skin contact process. On the contrary, grapes of the Royat system might be more appropriate to produce full-bodied wines with higher ageing potential, due to their more appropriate tannin structure, by using longer maceration periods.

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De Taeye, Cédric, Marie Bodart, Gilles Caullet et Sonia Collin. « Roasting conditions for preserving cocoa flavan-3-ol monomers and oligomers : interesting behaviour of Criollo clones ». Journal of the Science of Food and Agriculture 97, n^o 12 (7 mars 2017) : 4001–8. http://dx.doi.org/10.1002/jsfa.8265.

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Muncaciu, Maria Laura, Fernando Zamora Marin, Nastasia Pop, Anca Cristina Babes, Claudiu Ioan Bunea, Stefania Silvia Balea et Anamaria Calugar. « Functional Tannins in Grape Pomace Flours of Feteasca Neagra and Italian Riesling ». Revista de Chimie 69, n^o 9 (15 octobre 2018) : 2372–76. http://dx.doi.org/10.37358/rc.18.9.6536.

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The aim of this study was to analyze the content of functional tannins in grape pomace skin, seed, and mixed flour, from Feteasca Neagra and Italian Riesling varieties. Results showed that all compounds were present in the highest concentration in grape pomace seed flours and the lowest in skin flours. The concentration of total tannins and total flavan-3-ol monomers in all flour samples ranged from 37.34 to 72.28 mg epicatechin/g dry weight and 0.57 to 3.13 mg/g dry weight, respectively. Among monomers, (+)-catechin was found in the highest concentration, except in Italian Riesling seed flours, where (-)-epicatechin was predominant. The mDP of proanthocyanidins in seed flour (7.15 to 8.07) is lower than that of skin flours (10.83 to 18.43) while the opposite was observed for %G. As a result, all Feteasca Neagra and Italian Riesling grape pomace flours, especially seed flour, could be used as sources of functional tannins in alimentary or pharmaceutical industry.

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Zhao, Xinjie, Bo Deng, Jingxia Mu, Chunguang Li, Feng Wu, Ning Han et Yueling Zhao. « Composition of Flavan-3-ol Monomers in Mature Cabernet Sauvignon Fruit at Different Grapevine Age in Yantai, China ». Asian Journal of Chemistry 25, n^o 6 (2013) : 3127–33. http://dx.doi.org/10.14233/ajchem.2013.13551.

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Novikova, I. V., P. V. Rukavitsyn et A. S. Muravev. « Review : dry hopping in brewing ». Proceedings of the Voronezh State University of Engineering Technologies 80, n^o 2 (2 octobre 2018) : 144–49. http://dx.doi.org/10.20914/2310-1202-2018-2-144-149.

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Dry hopping defined as the addition of hops or hops-products at the cold stage of the brewing process. The practice of dry hopping is currently used in many American styles of beer (IPA, APA, Imperial Stout), Belgian (Ali and Tripoli), traditional British (IPA, Extra Special Bitter), as well as other styles of beer with a developed aromatic component. The main volatile bitter and aromatic components of hops include terpenes (myrcene, humulene and betacarotene), which are characterized by “herbaceous” aroma. There are also linalool and geraniol, which give floral and fruity notes. Terpineol and pinene are making a resinous character. Currently developed special technology, the introduction of hops and the appropriate equipment for dry hopping: flower hops; hop suspension; hop pellets; semi-automatic methods. Dry hopping carried out to increase the “hoppy” aroma of beer and found application due to the increased popularity of small brewing in the world. Since dry hopping performed at relatively low temperatures thermal decomposition and volatilization of aromatic compounds is significantly reduced. This results in a higher concentration of these compounds in the finished product. The source of the aromatic properties of the beer is the polyphenols. In the process of dry hopping about 80-90% of polyphenols extracted during the first 12 hours. Flavan-3-ols increases perceived bitterness and astringency. Monomers and oligomers of flavan-3-ol play a role in the stability of taste, colloidal stability and foam resistance of the drink, have antiradical and antioxidant properties.

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Frost, Scott, Larry Lerno, Jerry Zweigenbaum, Hildegarde Heymann et Susan Ebeler. « Characterization of Red Wine Proanthocyanidins Using a Putative Proanthocyanidin Database, Amide Hydrophilic Interaction Liquid Chromatography (HILIC), and Time-of-Flight Mass Spectrometry ». Molecules 23, n^o 10 (18 octobre 2018) : 2687. http://dx.doi.org/10.3390/molecules23102687.

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Proanthocyanidins are complex polymers of flavan-3-ol monomers and play a key sensory and health role in foods and beverages. We describe here a novel method for characterizing wine proanthocyanidins using a theoretical database comprised of the chemical formula and exact mass of 996 compounds. The database was constructed using the four primary grape and wine proanthocyanidin monomers: (epi)catechin, (epi)catechin-3-O-gallate, (epi)gallocatechin, and (epi)gallocatechin-3-O-gallate, each combined in all possible combinations up to a polymerization of 10. The database was queried against spectra collected using ultrahigh performance liquid chromatography (UHLPC) with a hydrophilic interaction liquid chromatography (HILIC) column and coupled to a high-resolution accurate mass quadrupole time-of-flight mass spectrometer (Q-TOF MS). Two wine samples produced with different post fermentation maceration were analyzed using the presented method to demonstrate application for analysis of diverse proanthocyanidins. The first sample was pressed immediately at the end of fermentation when all sugar had been utilized and the second received eight weeks of post fermentation maceration. The HILIC column combined with high resolution tandem mass spectrometry and database matching provided tentative identification of 89 compounds with excellent resolution and without the need for two-dimensional separations. The identified compounds were visualized with Kendrick mass analysis, a simple technique allowing for rapid visualization of which compounds are present in a given sample.

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Monagas, María, Carmen Gómez-Cordovés, Begoña Bartolomé, Olga Laureano et Jorge M. Ricardo da Silva. « Monomeric, Oligomeric, and Polymeric Flavan-3-ol Composition of Wines and Grapes fromVitis viniferaL. Cv. Graciano, Tempranillo, and Cabernet Sauvignon ». Journal of Agricultural and Food Chemistry 51, n^o 22 (octobre 2003) : 6475–81. http://dx.doi.org/10.1021/jf030325+.

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Rupasinghe, Vasantha, Sandhya V. Neir et Indu Parmar. « Polyphenol characterization, anti-oxidant, anti-proliferation and anti-tyrosinase activity of cranberry pomace ». Functional Foods in Health and Disease 6, n^o 11 (30 novembre 2016) : 754. http://dx.doi.org/10.31989/ffhd.v6i11.292.

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Background: Cranberry pomace (CP), an underutilized by-product from juice processing, contains a wide range of biologically active compounds that can be recovered and used in a variety of applications in functional foods and nutraceuticals. Methods: In this study, analytical chemical techniques such as solvent extractions and characterization of extracts in respect with their phenolic content were performed using ultra-high performance liquid chromatography mass spectrometry (UPLC-MS) and spectrophotometry. Crude CP extract and its phenolic acids, flavonols, anthocyanins and proanthocyanidins–rich fractions were then evaluated for their anti-oxidant capacity, tyrosinase inhibitory activity, and anti-proliferation activity against hepatocellular carcinoma HepG2 cells. Results: On a dry weight basis, the different CP fractions contained seven major anthocyanins (0.1-125 mg/g), six major phenolic acids (0.8-31 mg/g), seven flavonols (1-126 mg/g) and five flavan-3-ols (0.1-12 mg/g). Fractions rich in flavonols exhibited the most potent antioxidant capacities with ferric ion reducing antioxidant power values of 1.8-1.9 mmole/g and 2, 2-diphenyl-1-picrylhydrazyl radical scavenging IC50 values of 15.1-15.2 mg/L respectively. On the other hand, fractions rich in phenolic acids and flavan-3-ol monomers demonstrated the most potent anti-tyrosinase activity (IC50=6.1-6.2 mg/L) and anti-proliferative activity (IC50=7.8-15.8 mg/L). Generally, all the fractions exhibited a dose-response relationship in the selected biological activity assays.Conclusion: This study suggests an effective utilization of CP to obtain biologically active fractions with potential to be used in functional foods and nutraceuticals designed for the prevention of chronic diseases associated with oxidative stress.Keywords: cranberry pomace, polyphenol, anti-tyrosinase, anti-proliferation, nutraceuticals, functional foods

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de Gaulejac, Nathalie Vivas, Nicolas Vivas, Marie-Fran�oise Nonier, Christelle Absalon et Guy Bourgeois. « Study and quantification of monomeric flavan-3-ol and dimeric procyanidin quinonic forms by HPLC/ESI-MS. Application to red wine oxidation ». Journal of the Science of Food and Agriculture 81, n^o 12 (2001) : 1172–79. http://dx.doi.org/10.1002/jsfa.926.

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Balea, Ştefania Silvia, Alina Elena Pârvu, Nastasia Pop, Fernando Zamora Marín et Marcel Pârvu. « Polyphenolic Compounds, Antioxidant, and Cardioprotective Effects of Pomace Extracts from Fetească Neagră Cultivar ». Oxidative Medicine and Cellular Longevity 2018 (2018) : 1–11. http://dx.doi.org/10.1155/2018/8194721.

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Grape pomace is a potential source of natural antioxidant agents. Phenolic compounds and antioxidant and cardioprotective properties of fresh and fermented pomace extracts obtained from Vitis vinifera L. red variety Fetească neagră grown in Romania in 2015 were investigated. Grape pomace extracts total phenolic index, total tannins, total anthocyanins, proanthocyanidins, flavan-3-ol monomers, stilbenes, and DPPH free radical scavenger were measured. The effect of a seven-day pretreatment with grape pomace extracts on the isoprenaline-induced infarct-like lesion in rats was assessed by ECG monitoring, serum levels of creatine kinase, aspartate transaminase, and alanine transaminase. Total serum oxidative status, total antioxidant response, oxidative stress index, malondialdehyde, total thiols, and nitric oxide have been also assessed. Higher phenolic content and antioxidant activity were found in fermented pomace extracts when compared to fresh pomace extracts. Pretreatment with grape pomace extracts significantly improved cardiac and oxidative stress parameters. In conclusion, Fetească neagră pomace extracts had a good in vitro antioxidant activity due to an important phenolic content. In vivo, the extracts had cardioprotective effects against isoprenaline-induced infarct-like lesion by reducing oxidative stress, fresh pomace extracts having a better effect.

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Noda, Kota, Eisuke Kato et Jun Kawabata. « Search for Compounds Suppressing Intestinal α-Glucosidase Expression in Caco-2 Cells ». ICONIET PROCEEDING 2, n^o 2 (13 février 2019) : 96–101. http://dx.doi.org/10.33555/iconiet.v2i2.18.

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Diabetes is a chronic disease characterized by elevated blood glucose level.Reducing carbohydrate absorption from the intestinal tract is an effective strategy to control post-meal blood glucose level. Inhibition of intestinal α-glucosidase, involved in digestion of carbohydrates, is known as an approach to accomplish this. On the other hand, reduction of α-glucosidase amount is expected to work in the similar manner. However, none of the previousstudy pursues this approach. A convenient assay was developed to evaluate α-glucosidase amount employing Caco-2 cells, the intestinal epithelial cell model reported to express α-glucosidase. Sixty plants were screened and two candidate plants, Calluna vulgaris and Perilla frutescens var. crispa were found to reduce α-glucosidase expression. C. vulgaris extract was subjected to activity guided isolation. Proanthocyanidin was identified as the active principle which was analyzed by thiol decomposition to reveal the components as a mixture ofcatechin, epicatechin, epigallocatechin, and A type procyanidin dimer. The proanthocyanidin suppressed about 30% of α-glucosidase amount evaluated through convenient assay, and suppressed bulk of mRNA expression level of sucrase-isomaltase (SI) at 0.125 mg/mL. Several flavan-3-ol monomers were also tested, and epicatechin gallate and epigallocatechin gallate were found to suppress α-glucosidase amount significantly.

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Maffei, Massimo E., Cristiano Salata et Giorgio Gribaudo. « Tackling the Future Pandemics : Broad-Spectrum Antiviral Agents (BSAAs) Based on A-Type Proanthocyanidins ». Molecules 27, n^o 23 (30 novembre 2022) : 8353. http://dx.doi.org/10.3390/molecules27238353.

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A-type proanthocyanidins (PAC-As) are plant-derived natural polyphenols that occur as oligomers or polymers of flavan-3-ol monomers, such as (+)-catechin and (−)-epicatechin, connected through an unusual double A linkage. PAC-As are present in leaves, seeds, flowers, bark, and fruits of many plants, and are thought to exert protective natural roles against microbial pathogens, insects, and herbivores. Consequently, when tested in isolation, PAC-As have shown several biological effects, through antioxidant, antibacterial, immunomodulatory, and antiviral activities. PAC-As have been observed in fact to inhibit replication of many different human viruses, and both enveloped and non-enveloped DNA and RNA viruses proved sensible to their inhibitory effect. Mechanistic studies revealed that PAC-As cause reduction of infectivity of viral particles they come in contact with, as a result of their propensity to interact with virion surface capsid proteins or envelope glycoproteins essential for viral attachment and entry. As viral infections and new virus outbreaks are a major public health concern, development of effective Broad-Spectrum Antiviral Agents (BSAAs) that can be rapidly deployable even against future emerging viruses is an urgent priority. This review summarizes the antiviral activities and mechanism of action of PAC-As, and their potential to be deployed as BSAAs against present and future viral infections.

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Padilla-González, Guillermo F., Esther Grosskopf, Nicholas J. Sadgrove et Monique S. J. Simmonds. « Chemical Diversity of Flavan-3-Ols in Grape Seeds : Modulating Factors and Quality Requirements ». Plants 11, n^o 6 (18 mars 2022) : 809. http://dx.doi.org/10.3390/plants11060809.

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Grape seeds are a rich source of flavan-3-ol monomers, oligomers, and polymers. The diverse profile of compounds includes mainly B-type procyanidins (especially C4→C8 linked molecules) and the key monomers, catechin, and epicatechin that are positively implicated in the ‘French Paradox’. Today grape seed nutraceuticals have become a multi-million-dollar industry. This has created incentives to elucidate the variations in chemistry across cultivars, to identify signs of adulteration, and to understand the intrinsic and extrinsic factors controlling the expression of metabolites in the seeds’ metabolome. This review provides a critical overview of the existing literature on grape seed chemistry. Although the biosynthetic pathways for polymeric procyanidins in seeds have not yet been explained, abiotic factors have been shown to modulate associated genes. Research of extrinsic factors has demonstrated that the control of procyanidin expression is strongly influenced, in order of importance, by genotype (species first, then variety) and environment, as claimed anecdotally. Unfortunately, research outcomes on the effects of abiotic factors have low certainty, because effects can be specific to genotype or variety, and there is limited control over physical metrics in the field. Thus, to gain a fuller understanding of the effects of abiotic factors and biosynthetic pathways, and realise potential for optimisation, a more fundamental research approach is needed. Nevertheless, the current synthesis offers insight into the selection of species or varieties according to the profile of polyphenols, as well as for optimisation of horticultural practices, with a view to produce products that contain the compounds that support health claims.

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Zamora-Ros, Raul, Viktoria Knaze, Leila Luján-Barroso, Isabelle Romieu, Augustin Scalbert, Nadia Slimani, Anette Hjartåker et al. « Differences in dietary intakes, food sources and determinants of total flavonoids between Mediterranean and non-Mediterranean countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study ». British Journal of Nutrition 109, n^o 8 (14 septembre 2012) : 1498–507. http://dx.doi.org/10.1017/s0007114512003273.

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A greater adherence to the traditional Mediterranean (MED) diet is associated with a reduced risk of developing chronic diseases. This dietary pattern is based on higher consumption of plant products that are rich in flavonoids. We compared the total flavonoid dietary intakes, their food sources and various lifestyle factors between MED and non-MED countries participating in the EPIC study. Flavonoid intakes and their food sources for 35 628 subjects, aged 35–74 years and recruited between 1992 and 2000, in twenty-six study centres were estimated using standardised 24 h dietary recall software (EPIC-Soft®). An ad hoc food composition database on flavonoids was compiled using analytical data from the United States Department of Agriculture and Phenol-Explorer databases. Moreover, it was expanded to include using recipes, estimations of missing values and flavonoid retention factors. No significant differences in total flavonoid mean intake between non-MED countries (373·7 mg/d) and MED countries (370·2 mg/d) were observed. In the non-MED region, the main contributors were proanthocyanidins (48·2 %) and flavan-3-ol monomers (24·9 %) and the principal food sources were tea (25·7 %) and fruits (32·8 %). In the MED region, proanthocyanidins (59·0 %) were by far the most abundant contributor and fruits (55·1 %), wines (16·7 %) and tea (6·8 %) were the main food sources. The present study shows similar results for total dietary flavonoid intakes, but significant differences in flavonoid class intakes, food sources and some characteristics between MED and non-MED countries. These differences should be considered in studies about the relationships between flavonoid intake and chronic diseases.

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Navarro, Mirtha, Elizabeth Arnaez, Ileana Moreira, Alonso Hurtado, Daniela Monge et Maria Monagas. « Polyphenolic Composition and Antioxidant Activity of Uncaria tomentosa Commercial Bark Products ». Antioxidants 8, n^o 9 (23 août 2019) : 339. http://dx.doi.org/10.3390/antiox8090339.

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Uncaria tomentosa, which is widely commercialized as an herbal medicine, constitutes an important source of secondary metabolites with diverse biological activities. For instance, we have previously reported, for the first time, of a polyphenolic profile rich in proanthocyanidins from extracts of U. tomentosa plants, as well as their antioxidant capacity, antimicrobial activity on aerial bacteria, and cytotoxicity on cancer cell lines. These promising results prompted this research to evaluate the polyphenolic contents of U. tomentosa commercial products. We report a detailed study on the polyphenolic composition of extracts from U. tomentosa bark products (n = 18) commercialized in Costa Rica and Spain. Using HPLC-DAD/TQ-ESI-MS, a total of 25 polyphenolic compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavan-3-ol monomers, procyanidin dimers, procyanidin trimers, as well as propelargonidin dimers. Our findings on the polyphenolic profile for all commercial samples show analogous composition to previous reports on U. tomentosa bark material, for instance a 41–49% content of procyanidin dimers and the presence of propelargonidin dimers (8–15%). However, most of the 18 commercial samples exhibit low proanthocyanidin contents (254.8–602.8 µg/g), more similar to previous U. tomentosa inner bark reports, while some exhibit better results, with one sample (SP-2) showing the highest contents (2386.5 µg/g) representing twice the average value of all 18 commercial products. This sample also exhibits the highest total phenolics (TP) and total proanthocyanidins (PRO) contents, as well as the highest Oxygen Radical Absorbance Capacity (ORAC) value (1.31 µg TE/g). One-way Analysis of Variance (ANOVA) with a Tukey post hoc test indicated significant difference (p < 0.05) between products from Costa Rica and Spain for TP and PRO findings, with samples from Spain exhibiting a higher average value. In addition, Pearson correlation analysis results showed a positive correlation (p < 0.05) between TP, PRO, and ORAC results, and an especially important correlation between ORAC antioxidant values and procyanidin dimers (r = 0.843, p < 0.05), procyanidin trimers (r = 0.847, p < 0.05), and propelargonidin dimers (r = 0.851, p < 0.05) contents. Finally, Principal Component Analysis (PCA) results indicated some variability in the composition regardless of their origin. However, only one sample (SP-2) stands out significatively, showing the highest PC1 because of its particularly high proanthocyanidins contents, which could be attributed to the 15% bark polyphenolic extract labeled in this commercial product, which differentiate this sample from all other 17 commercial samples. Therefore, our findings confirmed previous results on the value of extracts in the elaboration of potential commercial products from U. tomentosa, rich in proanthocyanidins and exhibiting high antioxidant activity.

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VanderWeide, Joshua, Filippo Del Zozzo, Esmaeil Nasrollahiazar, James A. Kennedy, Enrico Peterlunger, Laura Rustioni et Paolo Sabbatini. « Influence of freezing and heating conditions on grape seed flavan-3-ol extractability, oxidation, and galloylation pattern ». Scientific Reports 12, n^o 1 (9 mars 2022). http://dx.doi.org/10.1038/s41598-022-07925-7.

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AbstractIn cool-climate viticulture, the short growing season can influence grape seed maturation by reducing the apparent oxidation of flavan-3-ol monomers and associated increase in seed browning. A reduction in seed maturation increases the potential extraction of flavan-3-ol monomers into wine during maceration operations, heightening bitterness. Here, we carried out a 2 × 2 factorial experiment to test the ability of freezing and heating treatments to advance maturation (decrease flavan-3-ol, improve browning) of (Vitis vinifera L.) Pinot noir and Cabernet Sauvignon seeds over a 24-h incubation period. Only freezing significantly increased seed browning in both cultivars. Subsequent correlations with seed flavan-3-ol monomer concentrations suggest that freezing enhanced the oxidation of these compounds. Interestingly, natural ripening and freezing reduced galloylated flavan-3-ol monomers to a greater extent than non-galloylated ones. This study provides new information regarding the susceptibility of flavan-3-ol monomers to freezing and heating, and also suggests that freezing can advance the maturation the seeds of under-ripe red vinifera grapes.

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Alfke, Julian, Uta Kampermann, Svetlana Kalinina et Melanie Esselen. « Isolation and structural elucidation of dimeric epigallocatechin-3-gallate autoxidation products and their antioxidant capacity ». European Food Research and Technology, 25 août 2021. http://dx.doi.org/10.1007/s00217-021-03846-3.

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AbstractDietary polyphenols like epigallocatechin-3-gallate (EGCG)—which represents the most abundant flavan-3-ol in green tea—are subject of several studies regarding their bioactivity and health-related properties. On many occasions, cell culture or in vitro experiments form the basis of published data. Although the stability of these compounds is observed to be low, many reported effects are directly related to the parent compounds whereas the impact of EGCG degradation and autoxidation products is not yet understood and merely studied. EGCG autoxidation products like its dimers theasinensin A and D, “P2” and oolongtheanin are yet to be characterized in the same extent as their parental polyphenol. However, to investigate the bioactivity of autoxidation products—which would minimize the discrepancy between in vitro and in vivo data—isolation and structure elucidation techniques are urgently needed. In this study, a new protocol to acquire the dimers theasinensin A and D as well as oolongtheanin is depicted, including a variety of spectroscopic and quadrupole time-of-flight high-resolution mass spectrometric (qTOF-HRMS) data to characterize and assign these isolates. Through nuclear magnetic resonance (NMR) spectroscopy, polarimetry, and especially circular dichroism (CD) spectroscopy after enzymatic hydrolysis the complementary atropisomeric stereochemistry of the isolated theasinensins is illuminated and elucidated. Lastly, a direct comparison between the isolated EGCG autoxidation products and the monomer itself is carried out regarding their antioxidant properties featuring Trolox equivalent antioxidant capacity (TEAC) values. These findings help to characterize these products regarding their cellular effects and—which is of special interest in the flavonoid group—their redox properties.

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Vangeel, Thijs, Ruben Smets, Mik Van Der Borght et Bert Sels. « Depolymerisation - hydrogenation of condensed tannins as strategy for generating flavan-3-ol monomers ». Green Chemistry, 2023. http://dx.doi.org/10.1039/d2gc04470f.

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Flavan-3-ol monomers are interesting, functionalised phenolic building blocks. Here, a strategy is presented for producing these flavan-3-ol monomers, starting from condensed tannins present in biomass waste streams such as tree...

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Monfoulet, Laurent-Emmanuel, Caroline Buffiere, Geoffrey Istas, Claire Dufour, Carine le Bourvelec, Sylvie Mercier, Dominique Bayle et al. « Effect of apple food matrix on plasma flavan-3-ols distribution and nutrigenomic profile in response to a nutritional challenge in minipigs ». Proceedings of the Nutrition Society 79, OCE2 (2020). http://dx.doi.org/10.1017/s0029665120001901.

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AbstractFood matrix is known to interact with some dietary constituents and microconstituents during digestion. These interactions may potentially affect the metabolism and bioavailability of some compounds, and as a consequence modulate their biological effects. In this context, the aim of this study was to determine the effect of apple food matrix on the bioavailability of flavan-3-ols and on the ability of these compounds to modulate the nutrigenomic response to a high fat challenge in minipigs.Adult male Yucatan minipigs (n = 5) were assigned to a random treatment sequence of high-fat meals non supplemented or supplemented with 250 g of raw apple, 250 g of apple puree or 1.4 g of apple polyphenols extract, with a 7-days washout period between each treatment. Each supplementation provided 155 mg flavan-3-ol monomers. At each treatment period, fasting- and 1h-, 2h-, 3h-postprandial blood samples were collected, and the concentration in flavan-3-ol monomers was measured on hydrolyzed serum, using UPLC-Q-TOF MS. The ability of apple-derived products to modulate the postprandial gene expression profile was assessed and compared in circulating PBMCs collected at 3 h after consumption of the four tested meals using a microarray analysis.Results show that the apple matrix did not affect the kinetic of the postprandial absorption of flavan-3-ol monomers. The total flavan-3-ols concentrations measured at peak were significantly higher in the extract (x1.75), suggesting an impact of the apple matrix on flavan-3-ols absorption. However, no significant difference in total flavanols was observed between raw apple and apple puree.Principal Component Analysis of the microarray data from PBMCs identified three distinct clusters of gene expression patterns: one corresponding to gene expression profiles after the high-fat meal, one for meal supplemented with raw apples or apple puree, and a third cluster for meal supplemented with polyphenol extract. A set of 309 genes was identified as differentially expressed by apple-derived products compared to high-fat meal alone, including 93 modulated with the three apple products. The variations in gene expression were similar for only 75% of the 93 genes, suggesting that the apple matrix affects the nutrigenomic response to flavan-3-ols. A bioinformatics analysis revealed that genes affected by apple-derived products are involved in inflammation and leukocyte transendothelial migration, suggesting a beneficial impact of apple-derived products.In conclusion, these results raise awareness for considering the impact of food matrix on the biological responsiveness of polyphenols in future nutritional studies.

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Battistoni, Benjamín, Juan Salazar, Wladimir Vega, Diego Valderrama-Soto, Pablo Jiménez-Muñoz, Ailynne Sepúlveda-González, Sebastián Ahumada et al. « An Upgraded, Highly Saturated Linkage Map of Japanese Plum (Prunus salicina Lindl.), and Identification of a New Major Locus Controlling the Flavan-3-ol Composition in Fruits ». Frontiers in Plant Science 13 (4 mars 2022). http://dx.doi.org/10.3389/fpls.2022.805744.

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Japanese plum fruits are rich in phenolic compounds, such as anthocyanins and flavan-3-ols, whose contents vary significantly among cultivars. Catechin (C) and epicatechin (EC) are flavan-3-ol monomers described in the fruits of this species and are associated with bitterness, astringency, antioxidant capacity, and susceptibility to enzymatic mesocarp browning. In this study, we aimed to identify quantitative trait loci (QTL) associated with the content of flavan-3-ol in Japanese plum fruits. We evaluated the content of C and EC in the mesocarp and exocarp of samples from 79 and 64 seedlings of an F1 progeny (<‘98–99’ × ‘Angeleno’>) in the first and second seasons, respectively. We also constructed improved versions of linkage maps from ‘98–99’ and ‘Angeleno,’ presently called single-nucleotide polymorphisms (SNPs) after mapping the already available GBS reads to Prunus salicina Lindl. cv. ‘Sanyueli’ v2.0 reference genome. These data allowed for describing a cluster of QTLs in the cultivar, ‘Angeleno,’ associated with the flavan-3-ol composition of mesocarp and exocarp, which explain up to 100% of the C/EC ratio. Additionally, we developed a C/EC metabolic marker, which was mapped between the markers with the highest log of odds (LOD) scores detected by the QTL analysis. The C/EC locus was located in the LG1, at an interval spanning 0.70 cM at 108.30–108.90 cM. Our results suggest the presence of a novel major gene controlling the preferential synthesis of C or EC in the Japanese plum fruits. This study is a significant advance in understanding the regulation of synthesizing compounds associated with fruit quality, postharvest, and human health promotion.

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Yu, Keji, Richard A. Dixon et Changqing Duan. « A role for ascorbate conjugates of (+)-catechin in proanthocyanidin polymerization ». Nature Communications 13, n^o 1 (14 juin 2022). http://dx.doi.org/10.1038/s41467-022-31153-2.

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AbstractProanthocyanidins (PAs) are natural polymers of flavan-3-ols, commonly (+)-catechin and (−)-epicatechin. However, exactly how PA oligomerization proceeds is poorly understood. Here we show, both biochemically and genetically, that ascorbate (AsA) is an alternative “starter unit” to flavan-3-ol monomers for leucocyanidin-derived (+)-catechin subunit extension in the Arabidopsis thaliana anthocyanidin synthase (ans) mutant. These (catechin)n:ascorbate conjugates (AsA-[C]n) also accumulate throughout the phase of active PA biosynthesis in wild-type grape flowers, berry skins and seeds. In the presence of (−)-epicatechin, AsA-[C]n can further provide monomeric or oligomeric PA extension units for non-enzymatic polymerization in vitro, and their role in vivo is inferred from analysis of relative metabolite levels in both Arabidopsis and grape. Our findings advance the knowledge of (+)-catechin-type PA extension and indicate that PA oligomerization does not necessarily proceed by sequential addition of a single extension unit. AsA-[C]n defines a new type of PA intermediate which we term “sub-PAs”.

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Parmenter, Ben, Frederik Dalgaard, Kevin Murray, Aedin Cassidy, Catherine P. Bondonno, Joshua R. Lewis, Kevin D. Croft et al. « 326Flavonoid intake and ischemic stroke incidence in the Danish Diet, Cancer, and Health Cohort ». International Journal of Epidemiology 50, Supplement_1 (1 septembre 2021). http://dx.doi.org/10.1093/ije/dyab168.523.

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Abstract Background Flavonoid-rich foods may contribute to a lower risk of ischemic stroke through their anti-inflammatory, anti-atherogenic, and anti-thrombotic properties. We aimed to examine the relationship between flavonoid intake and ischemic stroke incidence in participants from the Danish Diet, Cancer, and Health study. Methods In this prospective cohort study, 55,169 Danish citizens without a prior ischemic stroke (median [IQR] age at enrolment of 56 [52 – 60] years), were followed for 21 [20 – 22] years. Baseline flavonoid intake was estimated from food frequency questionnaires using the Phenol-Explorer database. Incident cases of stroke were identified from Danish nation-wide public health registries. Associations between quintiles of flavonoid intake and incident ischemic stroke were assessed using Cox proportional hazard models adjusting for age, sex, BMI, smoking status, physical activity, alcohol intake, education, and income. Results During follow-up, 4,317 individuals experienced an ischemic stroke. Compared to participants in quintile one and after multivariable adjustments, those in quintile five for intake of total flavonoids, flavonols and oligo+polymers had a 12% [HR (95% CI): 0.88 (0.81, 0.96)], 10% [0.90 (0.82, 0.98)], and 18% [0.82 (0.75, 0.89)], lower risk of ischemic stroke incidence, respectively. Intake of flavan-3-ol monomers, anthocyanins, flavanones and flavones were not associated with incident ischemic stroke. Conclusions A moderate habitual intake of flavonoids, in particular the flavonol and flavan-3-ol oligo+polymer subclasses, is associated with a lower risk of ischemic stroke. Key messages Flavonoid rich foods appear protective against ischemic stroke.

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Parmenter, Benjamin H., Kevin D. Croft, Lachlan Cribb, Matthew B. Cooke, Catherine P. Bondonno, Ana Lea, Grace M. McPhee et al. « Higher habitual dietary flavonoid intake associates with lower central blood pressure and arterial stiffness in healthy older adults ». British Journal of Nutrition, 23 août 2021, 1–11. http://dx.doi.org/10.1017/s000711452100324x.

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Abstract Flavonoids have shown anti-hypertensive and anti-atherosclerotic properties: the impact of habitual flavonoid intake on vascular function, central haemodynamics and arterial stiffness may be important. We investigated the relationship between habitual flavonoid consumption and measures of central blood pressure and arterial stiffness. We performed cross-sectional analysis of 381 non-smoking healthy older adults (mean age 66·0 (sd 4·1) years; BMI, 26·4 (sd 4·41) kg/m2; 41 % male) recruited as part of the Australian Research Council Longevity Intervention study. Flavonoid intake (i.e. flavonols, flavones, flavanones, anthocyanins, isoflavones, flavan-3-ol monomers, proanthocyanidins, theaflavins/thearubigins and total consumption) was estimated from FFQ using the US Department of Agriculture food composition databases. Measures of central haemodynamics and arterial stiffness included systolic blood pressure (cSBP), diastolic blood pressure (cDBP), mean arterial pressure (cMAP) and augmentation index (cAIx). After adjusting for demographic and lifestyle confounders, each sd/d higher intake of anthocyanins ((sd 44·3) mg/d) was associated with significantly lower cDBP (−1·56 mmHg, 95 % CI −2·65, −0·48) and cMAP (−1·62 mmHg, 95 % CI −2·82, −0·41). Similarly, each sd/d higher intake of flavanones ((sd 19·5) mg/d) was associated with ~1 % lower cAIx (−0·93 %, 95 % CI −1·77, −0·09). These associations remained signiﬁcant after additional adjustment for (1) a dietary quality score and (2) other major nutrients that may affect blood pressure or arterial stiffness (i.e. Na, K, Ca, Mg, n-3, total protein and fibre). This study suggests a possible benefit of dietary anthocyanin and flavanone intake on central haemodynamics and arterial stiffness; these findings require corroboration in further research.

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