title: In vitro transformation of chlorogenic acid by human gut microbiota.
abstract: METHODS
  Chlorogenic acid (3-O-caffeoyl-quinic acid, C-QA), the caffeic ester of quinic acid, is one of the most abundant phenolic acids in Western diet. The majority of C-QA escapes absorption in the small intestine and reaches the colon, where the resident microbiota transforms it into several metabolites. C-QA conversion by the gut microbiota from nine subjects was compared to evaluate the variability of bacterial metabolism. It was investigated whether a potentially probiotic Bifidobacterium strain, capable of C-QA hydrolysis, could affect C-QA fate.
  
  
  RESULTS
  Bioconversion experiments exploiting the microbiota from diverse subjects revealed that C-QA was metabolized through a succession of hydrogenation, dexydroxylation and ester hydrolysis, occurring in different order among the subjects. Transformation may proceed also through quinic acid residue breakdown, since caffeoyl-glycerol intermediates were identified (HPLC-MS/MS, Q-TOF). All the pathways converged on 3-(3-hydroxyphenyl)-propanoic acid, which was transformed to hydroxyphenyl-ethanol and/or phenylacetic acid in few subjects. A strain of Bifidobacterium animalis able to hydrolyze C-QA was added to microbiota cultures. It affected microbial composition but not to such an extent that C-QA metabolism was modified.
  
  
  CONCLUSIONS
  A picture of the variability of microbiota C-QA transformations among subjects is provided. The transformation route through caffeoyl-glycerol intermediates is described for the first time.
authors.affiliation: Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Tomas-Barberan
authors.forename: Rocío
authors.initials: R
authors.lastname: García-Villalba
authors.forename: Andrea
authors.initials: A
authors.lastname: Quartieri
authors.forename: Stefano
authors.initials: S
authors.lastname: Raimondi
authors.forename: Alberto
authors.initials: A
authors.lastname: Amaretti
authors.forename: Alan
authors.initials: A
authors.lastname: Leonardi
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
mesh_terms: D001644:Bifidobacterium / Q000378:metabolism; D002726:Chlorogenic Acid / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D006868:Hydrolysis; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D064307:Microbiota; D019936:Probiotics; D053719:Tandem Mass Spectrometry
chemical_list: D002726:Chlorogenic Acid
keywords: Bifidobacterium; Bioconversion; Chlorogenic acid; Intestinal microbiota; Probiotic