title: Microbial catabolism of procyanidins by human gut microbiota.
abstract: METHODS
  A major portion of ingested procyanidins is degraded by human microbiota in the colon into various phenolic compounds. These microbial metabolites are thought to contribute to the health benefits of procyanidins in vivo. The objective of this study was to identify and quantify the microbial metabolites of procyanidins after anaerobic fermentation with human microbiota.
  
  
  RESULTS
  (-)-Epicatechin, (+)-catechin, procyanidin B2, procyanidin A2, partially purified apple and cranberry procyanidins were incubated with human microbiota at a concentration equivalent to 0.5 mM epicatechin. GC-MS analysis showed that common metabolites of all six substrates were benzoic acid, 2-phenylacetic acid, 3-phenylpropionic acid, 2-(3'-hydroxyphenyl)acetic acid, 2-(4'-hydroxyphenyl)acetic acid, 3-(3'-hydroxyphenyl)propionic acid, and hydroxyphenylvaleric acid. 5-(3',4'-Dihydroxyphenyl)-γ-valerolactones and 5-(3'-hydroxyphenyl)-γ-valerolactones were identified as the microbial metabolites of epicatechin, catechin, procyanidin B2, and apple procyanidins but not from the procyanidin A2 or cranberry procyanidin ferments. 2-(3',4'-Dihydroxyphenyl)acetic acid was only found in the fermented broth of procyanidin B2, A2, apple, and cranberry procyanidins. The mass recoveries of microbial metabolites range from 20.0 to 56.9% for the six substrates after 24 h of fermentation.
  
  
  CONCLUSIONS
  Procyanidins, both B-type and A-type can be degraded by human gut microbiota. The microbial metabolites may contribute to the bioactivities of procyanidins.
authors.affiliation: Department of Food Science and Human Nutrition, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA.
authors.forename: Keqin
authors.initials: K
authors.lastname: Ou
authors.forename: Paul
authors.initials: P
authors.lastname: Sarnoski
authors.forename: Keith R
authors.initials: KR
authors.lastname: Schneider
authors.forename: Kaijie
authors.initials: K
authors.lastname: Song
authors.forename: Christina
authors.initials: C
authors.lastname: Khoo
authors.forename: Liwei
authors.initials: L
authors.lastname: Gu
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism; D019817:Benzoic Acid / Q000032:analysis; D044946:Biflavonoids / Q000378:metabolism; D002392:Catechin / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005285:Fermentation; D008401:Gas Chromatography-Mass Spectrometry; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D027845:Malus / Q000737:chemistry; D064307:Microbiota; D008970:Molecular Weight; D010636:Phenols / Q000032:analysis; D010648:Phenylacetates / Q000032:analysis; D010666:Phenylpropionates / Q000032:analysis; D010936:Plant Extracts; D044945:Proanthocyanidins / Q000378:metabolism*; D011422:Propionates / Q000032:analysis; D029799:Vaccinium macrocarpon / Q000737:chemistry; D014631:Valerates / Q000032:analysis
chemical_list: C491266:3-hydroxyphenylpropionic acid; D044946:Biflavonoids; D010636:Phenols; D010648:Phenylacetates; D010666:Phenylpropionates; D010936:Plant Extracts; D044945:Proanthocyanidins; D011422:Propionates; D014631:Valerates; C542735:procyanidin A2; C479580:procyanidin B2; C035253:3-phenylpropionic acid; C054012:2,4-dihydroxyphenylacetic acid; D002392:Catechin; D019817:Benzoic Acid; C008069:3-hydroxybenzeneacetic acid
keywords: Apple; Cranberry; Flavan-3-ols; Gut microbiota; Procyanidins