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Flavan-3-ol

August 25, 2023

Not to be confused with Flavonol.

Flavan-3-ols (sometimes referred to as flavanols) are a subgroup of flavonoids. They are derivatives of flavans that possess a 2-phenyl-3,4-dihydro-2H-chromen-3-ol skeleton. Flavan-3-ols are structurally diverse and include a range of compounds, such as catechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, proanthocyanidins, theaflavins, thearubigins. They play a part in plant defense and are present in the majority of plants.[1]

Chemical structure of flavan-3-ol

Chemical structure

The single-molecule (monomer) catechin, or isomer epicatechin (see diagram), adds four hydroxyls to flavan-3-ol, making building blocks for concatenated polymers (proanthocyanidins) and higher order polymers (anthocyanidins).[2]

Flavan-3-ols possess two chiral carbons, meaning four diastereoisomers occur for each of them. They are distinguished from the yellow, ketone-containing flavonoids such as quercitin and rutin, which are called flavonols. Early use of the term bioflavonoid was imprecisely applied to include the flavanols, which are distinguished by absence of ketone(s). Catechin monomers, dimers, and trimers (oligomers) are colorless. Higher order polymers, anthocyanidins, exhibit deepening reds and become tannins.[2]

Catechin and epicatechin are epimers, with (–)-epicatechin and (+)-catechin being the most common optical isomers found in nature. Catechin was first isolated from the plant extract catechu, from which it derives its name. Heating catechin past its point of decomposition releases pyrocatechol (also called catechol), which explains the common origin of the names of these compounds.

Epigallocatechin and gallocatechin contain an additional phenolic hydroxyl group when compared to epicatechin and catechin, respectively, similar to the difference in pyrogallol compared to pyrocatechol.

Catechin gallates are gallic acid esters of the catechins; an example is epigallocatechin gallate, which is commonly the most abundant catechin in tea. Proanthocyanidins and thearubigins are oligomeric flavan-3-ols.

In contrast to many other flavonoids, flavan-3-ols do not generally exist as glycosides in plants.[3]

 
Structures (Epi)catechin, (epi)catechin-gallate, (epi)gallocatechin and (epi)gallocatechin-gallate.

Biosynthesis of (–)-epicatechin

The flavonoids are products from a cinnamoyl-CoA starter unit, with chain extension using three molecules of malonyl-CoA. Reactions are catalyzed by a type III PKS enzyme. These enzyme do not use ACPSs, but instead employ coenzyme A esters and have a single active site to perform the necessary series of reactions, e.g. chain extension, condensation, and cyclization. Chain extension of 4-hydroxycinnamoyl-CoA with three molecules of malonyl-CoA gives initially a polyketide (Figure 1), which can be folded. These allow Claisen-like reactions to occur, generating aromatic rings.[4][5] Fluorescence-lifetime imaging microscopy (FLIM) can be used to detect flavanols in plant cells.[6]

 
Figure 1

Figure 1:Schematic overview of the flavan-3-ol (–)-epicatechin biosynthesis in plants: Enzymes are indicated in blue, abbreviated as follows: E1, phenylalanine ammonia lyase (PAL), E2, tyrosine ammonia lyase (TAL), E3, cinnamate 4-hydroxylase, E4, 4-coumaroyl: CoA-ligase, E5, chalcone synthase (naringenin-chalcone synthase), E6, chalcone isomerase, E7, Flavonoid 3'-hydroxylase, E8, flavonone 3-hydroxylase, E9, dihydroflavanol 4-reductase, E10, anthocyanidin synthase (leucoanthocyanidin dioxygenase), E11, anthocyanidin reductase. HSCoA, Coenzyme A. L-Tyr, L-tyrosine, L-Phe, L-phenylalanine.

Aglycones

Flavan-3-ols
Image Name Formula Oligomers
  Catechin, C, (+)-Catechin C15H14O6 Procyanidins
  Epicatechin, EC, (–)-Epicatechin (cis) C15H14O6 Procyanidins
  Epigallocatechin, EGC C15H14O7 Prodelphinidins
  Epicatechin gallate, ECG C22H18O10
  Epigallocatechin gallate, EGCG,
(–)-Epigallocatechin gallate		 C22H18O11
  Epiafzelechin C15H14O5
  Fisetinidol C15H14O5
  Guibourtinidol C15H14O4 Proguibourtinidins
  Mesquitol C15H14O6
  Robinetinidol C15H14O6 Prorobinetinidins

Dietary sources

See also: Polyphenols in tea, Polyphenols in wine, and Cocoa bean § Phytochemicals and research
 
Reported range of flavan-3-ol content in foods commonly consumed.[7]

Flavan-3-ols are abundant in teas derived from the tea plant Camellia sinensis, as well as in some cocoas (made from the seeds of Theobroma cacao), although the content is affected considerably by processing, especially in chocolate.[8][9] Flavan-3-ols are also present in the human diet in fruits, in particular pome fruits, berries, vegetables, and wine.[10] Their content in food is variable and affected by various factors, such as cultivar, processing, and preparation.[11]

Bioavailability and metabolism

The bioavailability of flavan-3-ols depends on the food matrix, type of compound and their stereochemical configuration.[12] While monomeric flavan-3-ols are readily taken up, oligomeric forms are not absorbed.[12][13] Most data for human metabolism of flavan-3-ols are available for monomeric compounds, especially epiatechin. These compounds are taken up and metabolized upon uptake in the jejunum,[14] mainly by O-methylation and glucuronidation,[15] and then further metabolized by the liver. The colonic microbiome has also an important role in the metabolism of flavan-3-ols and they are catabolized to smaller compounds such as 5-(3′/4′-dihydroxyphenyl)-γ-valerolactones and hippuric acid.[16][17] Only flavan-3-ols with an intact (epi)catechin moiety can be metabolized into 5-(3′/4′-dihydroxyphenyl)-γ-valerolactones (image in Gallery).[18]

Possible adverse effects

As catechins in green tea extract can be hepatotoxic, Health Canada and EFSA have advised for caution,[19] recommending intake should not exceed 800 mg per day.[20]

Research

See also: Cocoa bean § Phytochemicals and research

Research has shown that flavan-3-ols may affect vascular function, blood pressure, and blood lipids, with only minor effects demonstrated, as of 2019.[21][22] In 2015, the European Commission approved a health claim for cocoa solids containing 200 mg of flavanols, stating that such intake "may contribute to maintenance of vascular elasticity and normal blood flow".[23][24] As of 2022, food-based evidence indicates that intake of 400–600 mg per day of flavan-3-ols could have a small positive effect on cardiovascular biomarkers.[25]

Gallery

  •  

    Schematic representation of the flavan-3-ol (−)-epicatechin metabolism in humans as a function of time post-oral intake. SREM: structurally related (−)-epicatechin metabolites. 5C-RFM: 5-carbon ring fission metabolites. 3/1C-RFM: 3- and 1-carbon-side chain ring fission metabolites. The structures of the most abundant (−)-epicatechin metabolites present in the systemic circulation and in urine are depicted.[17]

  •  

    Flavan-3-ol precursors of the microbial metabolite 5-(3′/4′-dihydroxyphenyl)-γ-valerolactone (gVL). Only compounds with intact (epi)catechin moiety result in the formation of γVL by the intestinal microbiome. ECG, (−)-epicatechin-3-O-gallate; EGCG, Epigallocatechin gallate; EGC, Epigallocatechin.[18]

References

  1. ^ Ullah C, Unsicker SB, Fellenberg C, Constabel CP, Schmidt A, Gershenzon J, Hammerbacher A (December 2017). "Flavan-3-ols Are an Effective Chemical Defense against Rust Infection". Plant Physiology. 175 (4): 1560–1578. doi:10.1104/pp.17.00842. PMC 5717727. PMID 29070515.
  2. ^ a b Schwitters B, Masquelier J (1995). OPC in Practice (3rd ed.). OCLC 45289285.
  3. ^ Del Rio D, Rodriguez-Mateos A, Spencer JP, Tognolini M, Borges G, Crozier A (May 2013). "Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases". Antioxidants & Redox Signaling. 18 (14): 1818–1892. doi:10.1089/ars.2012.4581. PMC 3619154. PMID 22794138.
  4. ^ Dewick PM (2009). Medicinal Natural Products: a biosynthetic approach. John Wiley & Sons. p. 168. ISBN 978-0-471-49641-0.
  5. ^ Winkel-Shirley B (June 2001). "Flavonoid biosynthesis. A colorful model for genetics, biochemistry, cell biology, and biotechnology". Plant Physiology. 126 (2): 485–493. doi:10.1104/pp.126.2.485. PMC 1540115. PMID 11402179.
  6. ^ Mueller-Harvey I, Feucht W, Polster J, Trnková L, Burgos P, Parker AW, Botchway SW (March 2012). "Two-photon excitation with pico-second fluorescence lifetime imaging to detect nuclear association of flavanols". Analytica Chimica Acta. 719: 68–75. doi:10.1016/j.aca.2011.12.068. PMID 22340533. S2CID 24094780.
  7. ^ "Database on polyphenol content in foods, v. 3.6". Phenol Explorer. 2016.
  8. ^ Hammerstone JF, Lazarus SA, Schmitz HH (August 2000). "Procyanidin content and variation in some commonly consumed foods". The Journal of Nutrition. 130 (8S Suppl): 2086S–2092S. doi:10.1093/jn/130.8.2086S. PMID 10917927.
  9. ^ Payne MJ, Hurst WJ, Miller KB, Rank C, Stuart DA (October 2010). "Impact of fermentation, drying, roasting, and Dutch processing on epicatechin and catechin content of cacao beans and cocoa ingredients". Journal of Agricultural and Food Chemistry. 58 (19): 10518–10527. doi:10.1021/jf102391q. PMID 20843086.
  10. ^ Mabrym H, Harborne JB, Mabry TJ (1975). The Flavonoids. London: Chapman and Hall. ISBN 978-0-412-11960-6.
  11. ^ Manach C, Scalbert A, Morand C, Rémésy C, Jiménez L (May 2004). "Polyphenols: food sources and bioavailability". The American Journal of Clinical Nutrition. 79 (5): 727–747. doi:10.1093/ajcn/79.5.727. PMID 15113710.
  12. ^ a b Del Río D, Rodríguez Mateos A, Spencer JP, Tognolini M, Borges G, Crozier A (May 2013). "Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases". Antioxidants & Redox Signaling. 18 (14): 1818–1892. doi:10.1089/ars.2012.4581. PMC 3619154. PMID 22794138.
  13. ^ Rodríguez Mateos A, Weber T, Skene SS, Ottaviani JI, Crozier A, Kelm M, et al. (December 2018). "Assessing the respective contributions of dietary flavanol monomers and procyanidins in mediating cardiovascular effects in humans: randomized, controlled, double-masked intervention trial". The American Journal of Clinical Nutrition. 108 (6): 1229–1237. doi:10.1093/ajcn/nqy229. PMC 6290365. PMID 30358831.
  14. ^ Actis-Goretta L, Lévèques A, Rein M, Teml A, Schäfer C, Hofmann U, et al. (October 2013). "Intestinal absorption, metabolism, and excretion of (−)-epicatechin in healthy humans assessed by using an intestinal perfusion technique". The American Journal of Clinical Nutrition. 98 (4): 924–933. doi:10.3945/ajcn.113.065789. PMID 23864538.
  15. ^ Kuhnle G, Spencer JP, Schroeter H, Shenoy B, Debnam ES, Srai SK, et al. (October 2000). "Epicatechin and catechin are O-methylated and glucuronidated in the small intestine". Biochemical and Biophysical Research Communications. 277 (2): 507–512. doi:10.1006/bbrc.2000.3701. PMID 11032751.
  16. ^ Das NP (December 1971). "Studies on flavonoid metabolism. Absorption and metabolism of (+)-catechin in man". Biochemical Pharmacology. 20 (12): 3435–3445. doi:10.1016/0006-2952(71)90449-7. PMID 5132890.
  17. ^ a b Ottaviani JI, Borges G, Momma TY, et al. (July 2016). "The metabolome of [2-14C](−)-epicatechin in humans: implications for the assessment of efficacy, safety, and mechanisms of action of polyphenolic bioactives". Scientific Reports. 6 (1): 29034. Bibcode:2016NatSR...629034O. doi:10.1038/srep29034. PMC 4929566. PMID 27363516.
  18. ^ a b Ottaviani JI, Fong R, Kimball J, Ensunsa JL, Britten A, Lucarelli D, et al. (June 2018). "Evaluation at scale of microbiome-derived metabolites as biomarker of flavan-3-ol intake in epidemiological studies". Scientific Reports. 8 (1): 9859. Bibcode:2018NatSR...8.9859O. doi:10.1038/s41598-018-28333-w. PMC 6026136. PMID 29959422.
  19. ^ Health Canada (12 December 2017). "Summary Safety Review - Green tea extract-containing natural health products - Assessing the potential risk of liver injury (hepatotoxicity)". Health Canada, Government of Canada. Retrieved 2022-05-06.
  20. ^ Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B, Filipič M, et al. (April 2018). "Scientific opinion on the safety of green tea catechins". EFSA Journal. 16 (4): e05239. doi:10.2903/j.efsa.2018.5239. PMC 7009618. PMID 32625874.
  21. ^ Ried K, Fakler P, Stocks NP, et al. (Cochrane Hypertension Group) (April 2017). "Effect of cocoa on blood pressure". The Cochrane Database of Systematic Reviews. 4 (5): CD008893. doi:10.1002/14651858.CD008893.pub3. PMC 6478304. PMID 28439881.
  22. ^ Raman G, Avendano EE, Chen S, Wang J, Matson J, Gayer B, et al. (November 2019). "Dietary intakes of flavan-3-ols and cardiometabolic health: systematic review and meta-analysis of randomized trials and prospective cohort studies". The American Journal of Clinical Nutrition. 110 (5): 1067–1078. doi:10.1093/ajcn/nqz178. PMC 6821550. PMID 31504087.
  23. ^ "Article 13 (5): Cocoa flavanols; Search filters: Claim status - authorised; search - flavanols". European Commission, EU Register. 31 March 2015. Retrieved 8 September 2022.
  24. ^ "Scientific Opinion on the modification of the authorisation of a health claim related to cocoa flavanols and maintenance of normal endothelium-dependent vasodilation pursuant to Article 13(5) of Regulation (EC) No 1924/20061 following a request in accordance with Article 19 of Regulation (EC) No 1924/2006". EFSA Journal. 12 (5). 2014. doi:10.2903/j.efsa.2014.3654.
  25. ^ Crowe-White, Kristi M; Evans, Levi W; Kuhnle, Gunter G C; Milenkovic, Dragan; Stote, Kim; Wallace, Taylor; Handu, Deepa; Senkus, Katelyn E (3 October 2022). "Flavan-3-ols and cardiometabolic health: First ever dietary bioactive guideline". Advances in Nutrition: 2070–83. doi:10.1093/advances/nmac105.

External links

  •   Media related to Flavan-3-ols at Wikimedia Commons

August 25, 2023
flavan, confused, with, flavonol, sometimes, referred, flavanols, subgroup, flavonoids, they, derivatives, flavans, that, possess, phenyl, dihydro, chromen, skeleton, structurally, diverse, include, range, compounds, such, catechin, epicatechin, gallate, epiga. Not to be confused with Flavonol Flavan 3 ols sometimes referred to as flavanols are a subgroup of flavonoids They are derivatives of flavans that possess a 2 phenyl 3 4 dihydro 2H chromen 3 ol skeleton Flavan 3 ols are structurally diverse and include a range of compounds such as catechin epicatechin gallate epigallocatechin epigallocatechin gallate proanthocyanidins theaflavins thearubigins They play a part in plant defense and are present in the majority of plants 1 Chemical structure of flavan 3 ol Contents 1 Chemical structure 1 1 Biosynthesis of epicatechin 1 2 Aglycones 2 Dietary sources 3 Bioavailability and metabolism 4 Possible adverse effects 5 Research 6 Gallery 7 References 8 External linksChemical structure EditThe single molecule monomer catechin or isomer epicatechin see diagram adds four hydroxyls to flavan 3 ol making building blocks for concatenated polymers proanthocyanidins and higher order polymers anthocyanidins 2 Flavan 3 ols possess two chiral carbons meaning four diastereoisomers occur for each of them They are distinguished from the yellow ketone containing flavonoids such as quercitin and rutin which are called flavonols Early use of the term bioflavonoid was imprecisely applied to include the flavanols which are distinguished by absence of ketone s Catechin monomers dimers and trimers oligomers are colorless Higher order polymers anthocyanidins exhibit deepening reds and become tannins 2 Catechin and epicatechin are epimers with epicatechin and catechin being the most common optical isomers found in nature Catechin was first isolated from the plant extract catechu from which it derives its name Heating catechin past its point of decomposition releases pyrocatechol also called catechol which explains the common origin of the names of these compounds Epigallocatechin and gallocatechin contain an additional phenolic hydroxyl group when compared to epicatechin and catechin respectively similar to the difference in pyrogallol compared to pyrocatechol Catechin gallates are gallic acid esters of the catechins an example is epigallocatechin gallate which is commonly the most abundant catechin in tea Proanthocyanidins and thearubigins are oligomeric flavan 3 ols In contrast to many other flavonoids flavan 3 ols do not generally exist as glycosides in plants 3 Structures Epi catechin epi catechin gallate epi gallocatechin and epi gallocatechin gallate Biosynthesis of epicatechin Edit The flavonoids are products from a cinnamoyl CoA starter unit with chain extension using three molecules of malonyl CoA Reactions are catalyzed by a type III PKS enzyme These enzyme do not use ACPSs but instead employ coenzyme A esters and have a single active site to perform the necessary series of reactions e g chain extension condensation and cyclization Chain extension of 4 hydroxycinnamoyl CoA with three molecules of malonyl CoA gives initially a polyketide Figure 1 which can be folded These allow Claisen like reactions to occur generating aromatic rings 4 5 Fluorescence lifetime imaging microscopy FLIM can be used to detect flavanols in plant cells 6 Figure 1Figure 1 Schematic overview of the flavan 3 ol epicatechin biosynthesis in plants Enzymes are indicated in blue abbreviated as follows E1 phenylalanine ammonia lyase PAL E2 tyrosine ammonia lyase TAL E3 cinnamate 4 hydroxylase E4 4 coumaroyl CoA ligase E5 chalcone synthase naringenin chalcone synthase E6 chalcone isomerase E7 Flavonoid 3 hydroxylase E8 flavonone 3 hydroxylase E9 dihydroflavanol 4 reductase E10 anthocyanidin synthase leucoanthocyanidin dioxygenase E11 anthocyanidin reductase HSCoA Coenzyme A L Tyr L tyrosine L Phe L phenylalanine Aglycones Edit Flavan 3 ols Image Name Formula Oligomers Catechin C Catechin C15H14O6 Procyanidins Epicatechin EC Epicatechin cis C15H14O6 Procyanidins Epigallocatechin EGC C15H14O7 Prodelphinidins Epicatechin gallate ECG C22H18O10 Epigallocatechin gallate EGCG Epigallocatechin gallate C22H18O11 Epiafzelechin C15H14O5 Fisetinidol C15H14O5 Guibourtinidol C15H14O4 Proguibourtinidins Mesquitol C15H14O6 Robinetinidol C15H14O6 ProrobinetinidinsDietary sources EditSee also Polyphenols in tea Polyphenols in wine and Cocoa bean Phytochemicals and research Reported range of flavan 3 ol content in foods commonly consumed 7 Flavan 3 ols are abundant in teas derived from the tea plant Camellia sinensis as well as in some cocoas made from the seeds of Theobroma cacao although the content is affected considerably by processing especially in chocolate 8 9 Flavan 3 ols are also present in the human diet in fruits in particular pome fruits berries vegetables and wine 10 Their content in food is variable and affected by various factors such as cultivar processing and preparation 11 Bioavailability and metabolism EditThe bioavailability of flavan 3 ols depends on the food matrix type of compound and their stereochemical configuration 12 While monomeric flavan 3 ols are readily taken up oligomeric forms are not absorbed 12 13 Most data for human metabolism of flavan 3 ols are available for monomeric compounds especially epiatechin These compounds are taken up and metabolized upon uptake in the jejunum 14 mainly by O methylation and glucuronidation 15 and then further metabolized by the liver The colonic microbiome has also an important role in the metabolism of flavan 3 ols and they are catabolized to smaller compounds such as 5 3 4 dihydroxyphenyl g valerolactones and hippuric acid 16 17 Only flavan 3 ols with an intact epi catechin moiety can be metabolized into 5 3 4 dihydroxyphenyl g valerolactones image in Gallery 18 Possible adverse effects EditAs catechins in green tea extract can be hepatotoxic Health Canada and EFSA have advised for caution 19 recommending intake should not exceed 800 mg per day 20 Research EditSee also Cocoa bean Phytochemicals and research Research has shown that flavan 3 ols may affect vascular function blood pressure and blood lipids with only minor effects demonstrated as of 2019 21 22 In 2015 the European Commission approved a health claim for cocoa solids containing 200 mg of flavanols stating that such intake may contribute to maintenance of vascular elasticity and normal blood flow 23 24 As of 2022 food based evidence indicates that intake of 400 600 mg per day of flavan 3 ols could have a small positive effect on cardiovascular biomarkers 25 Gallery Edit Schematic representation of the flavan 3 ol epicatechin metabolism in humans as a function of time post oral intake SREM structurally related epicatechin metabolites 5C RFM 5 carbon ring fission metabolites 3 1C RFM 3 and 1 carbon side chain ring fission metabolites The structures of the most abundant epicatechin metabolites present in the systemic circulation and in urine are depicted 17 Flavan 3 ol precursors of the microbial metabolite 5 3 4 dihydroxyphenyl g valerolactone gVL Only compounds with intact epi catechin moiety result in the formation of gVL by the intestinal microbiome ECG epicatechin 3 O gallate EGCG Epigallocatechin gallate EGC Epigallocatechin 18 References Edit Ullah C Unsicker SB Fellenberg C Constabel CP Schmidt A Gershenzon J Hammerbacher A December 2017 Flavan 3 ols Are an Effective Chemical Defense against Rust Infection Plant Physiology 175 4 1560 1578 doi 10 1104 pp 17 00842 PMC 5717727 PMID 29070515 a b Schwitters B Masquelier J 1995 OPC in Practice 3rd ed OCLC 45289285 Del Rio D Rodriguez Mateos A Spencer JP Tognolini M Borges G Crozier A May 2013 Dietary poly phenolics in human health structures bioavailability and evidence of protective effects against chronic diseases Antioxidants amp Redox Signaling 18 14 1818 1892 doi 10 1089 ars 2012 4581 PMC 3619154 PMID 22794138 Dewick PM 2009 Medicinal Natural Products a biosynthetic approach John Wiley amp Sons p 168 ISBN 978 0 471 49641 0 Winkel Shirley B June 2001 Flavonoid biosynthesis A colorful model for genetics biochemistry cell biology and biotechnology Plant Physiology 126 2 485 493 doi 10 1104 pp 126 2 485 PMC 1540115 PMID 11402179 Mueller Harvey I Feucht W Polster J Trnkova L Burgos P Parker AW Botchway SW March 2012 Two photon excitation with pico second fluorescence lifetime imaging to detect nuclear association of flavanols Analytica Chimica Acta 719 68 75 doi 10 1016 j aca 2011 12 068 PMID 22340533 S2CID 24094780 Database on polyphenol content in foods v 3 6 Phenol Explorer 2016 Hammerstone JF Lazarus SA Schmitz HH August 2000 Procyanidin content and variation in some commonly consumed foods The Journal of Nutrition 130 8S Suppl 2086S 2092S doi 10 1093 jn 130 8 2086S PMID 10917927 Payne MJ Hurst WJ Miller KB Rank C Stuart DA October 2010 Impact of fermentation drying roasting and Dutch processing on epicatechin and catechin content of cacao beans and cocoa ingredients Journal of Agricultural and Food Chemistry 58 19 10518 10527 doi 10 1021 jf102391q PMID 20843086 Mabrym H Harborne JB Mabry TJ 1975 The Flavonoids London Chapman and Hall ISBN 978 0 412 11960 6 Manach C Scalbert A Morand C Remesy C Jimenez L May 2004 Polyphenols food sources and bioavailability The American Journal of Clinical Nutrition 79 5 727 747 doi 10 1093 ajcn 79 5 727 PMID 15113710 a b Del Rio D Rodriguez Mateos A Spencer JP Tognolini M Borges G Crozier A May 2013 Dietary poly phenolics in human health structures bioavailability and evidence of protective effects against chronic diseases Antioxidants amp Redox Signaling 18 14 1818 1892 doi 10 1089 ars 2012 4581 PMC 3619154 PMID 22794138 Rodriguez Mateos A Weber T Skene SS Ottaviani JI Crozier A Kelm M et al December 2018 Assessing the respective contributions of dietary flavanol monomers and procyanidins in mediating cardiovascular effects in humans randomized controlled double masked intervention trial The American Journal of Clinical Nutrition 108 6 1229 1237 doi 10 1093 ajcn nqy229 PMC 6290365 PMID 30358831 Actis Goretta L Leveques A Rein M Teml A Schafer C Hofmann U et al October 2013 Intestinal absorption metabolism and excretion of epicatechin in healthy humans assessed by using an intestinal perfusion technique The American Journal of Clinical Nutrition 98 4 924 933 doi 10 3945 ajcn 113 065789 PMID 23864538 Kuhnle G Spencer JP Schroeter H Shenoy B Debnam ES Srai SK et al October 2000 Epicatechin and catechin are O methylated and glucuronidated in the small intestine Biochemical and Biophysical Research Communications 277 2 507 512 doi 10 1006 bbrc 2000 3701 PMID 11032751 Das NP December 1971 Studies on flavonoid metabolism Absorption and metabolism of catechin in man Biochemical Pharmacology 20 12 3435 3445 doi 10 1016 0006 2952 71 90449 7 PMID 5132890 a b Ottaviani JI Borges G Momma TY et al July 2016 The metabolome of 2 14C epicatechin in humans implications for the assessment of efficacy safety and mechanisms of action of polyphenolic bioactives Scientific Reports 6 1 29034 Bibcode 2016NatSR 629034O doi 10 1038 srep29034 PMC 4929566 PMID 27363516 a b Ottaviani JI Fong R Kimball J Ensunsa JL Britten A Lucarelli D et al June 2018 Evaluation at scale of microbiome derived metabolites as biomarker of flavan 3 ol intake in epidemiological studies Scientific Reports 8 1 9859 Bibcode 2018NatSR 8 9859O doi 10 1038 s41598 018 28333 w PMC 6026136 PMID 29959422 Health Canada 12 December 2017 Summary Safety Review Green tea extract containing natural health products Assessing the potential risk of liver injury hepatotoxicity Health Canada Government of Canada Retrieved 2022 05 06 Younes M Aggett P Aguilar F Crebelli R Dusemund B Filipic M et al April 2018 Scientific opinion on the safety of green tea catechins EFSA Journal 16 4 e05239 doi 10 2903 j efsa 2018 5239 PMC 7009618 PMID 32625874 Ried K Fakler P Stocks NP et al Cochrane Hypertension Group April 2017 Effect of cocoa on blood pressure The Cochrane Database of Systematic Reviews 4 5 CD008893 doi 10 1002 14651858 CD008893 pub3 PMC 6478304 PMID 28439881 Raman G Avendano EE Chen S Wang J Matson J Gayer B et al November 2019 Dietary intakes of flavan 3 ols and cardiometabolic health systematic review and meta analysis of randomized trials and prospective cohort studies The American Journal of Clinical Nutrition 110 5 1067 1078 doi 10 1093 ajcn nqz178 PMC 6821550 PMID 31504087 Article 13 5 Cocoa flavanols Search filters Claim status authorised search flavanols European Commission EU Register 31 March 2015 Retrieved 8 September 2022 Scientific Opinion on the modification of the authorisation of a health claim related to cocoa flavanols and maintenance of normal endothelium dependent vasodilation pursuant to Article 13 5 of Regulation EC No 1924 20061 following a request in accordance with Article 19 of Regulation EC No 1924 2006 EFSA Journal 12 5 2014 doi 10 2903 j efsa 2014 3654 Crowe White Kristi M Evans Levi W Kuhnle Gunter G C Milenkovic Dragan Stote Kim Wallace Taylor Handu Deepa Senkus Katelyn E 3 October 2022 Flavan 3 ols and cardiometabolic health First ever dietary bioactive guideline Advances in Nutrition 2070 83 doi 10 1093 advances nmac105 External links Edit Media related to Flavan 3 ols at Wikimedia Commons Retrieved from https en wikipedia org w index php title Flavan 3 ol amp oldid 1171091112, wikipedia, wiki, book, books, library,

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