title: Bioavailability and catabolism of green tea flavan-3-ols in humans.
abstract: OBJECTIVE
  The aim of this study was to investigate green tea flavan-3-ol catabolism and plasma pharmacokinetic and urinary excretion by high-performance liquid chromatography with tandem mass spectrometry to evaluate their absolute bioavailability by taking into account all known and some unknown catabolites deriving from their interaction with the gastrointestinal tract and its host microflora.
  
  
  METHODS
  A feeding study was carried out in 20 healthy human volunteers who ingested 400 mL of a ready-to-drink green tea containing approximately 400 μmol of flavan-3-ols. Urine and plasma were collected for 4 and 24h, respectively, and 39 relevant catabolites were identified in these biological fluids by tandem mass spectrometry.
  
  
  RESULTS
  In biological fluids, 39 relevant flavan-3-ol catabolites were identified. In plasma, (-)-epigallocatechin-3-gallate was the only unmetabolized compound and the highest in absolute concentration compared with (-)-epigallocatechin and (-)-epicatechin conjugates. Colonic microflora-derived polyhydroxyphenyl-γ-valerolactones were by far the main urinary catabolites, averaging 10 times greater concentratin than flavan-3-ol conjugates. The calculated bioavailability was equal to 39% and it is interesting to notice the great variability in urinary excretion of colonic metabolites among participants, probably related to differences in their own colonic microflora.
  
  
  CONCLUSIONS
  This study demonstrates that green tea catechins are more bioavailable than previously observed when colonic ring fission metabolites are taken into consideration. Regular consumption of ready-to-drink green tea containing flavan-3-ols allows a non-marginal exposure of the human body to these catabolites, somehow justifying the numerous beneficial actions described as linked to green tea intake.
authors.affiliation: Department of Public Health, University of Parma, Parma, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Del Rio
authors.forename: Luca
authors.initials: L
authors.lastname: Calani
authors.forename: Chiara
authors.initials: C
authors.lastname: Cordero
authors.forename: Sara
authors.initials: S
authors.lastname: Salvatore
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Pellegrini
authors.forename: Furio
authors.initials: F
authors.lastname: Brighenti
mesh_terms: D000328:Adult; D002392:Catechin / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000097:blood / Q000737:chemistry / Q000378:metabolism* / Q000652:urine; D020719:Glucuronides / Q000097:blood / Q000737:chemistry / Q000652:urine; D006801:Humans; D007536:Isomerism; D007783:Lactones / Q000737:chemistry / Q000652:urine; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization; D013463:Sulfuric Acid Esters / Q000097:blood / Q000737:chemistry / Q000652:urine; D053719:Tandem Mass Spectrometry; D013662:Tea / Q000737:chemistry*; D013997:Time Factors; D055815:Young Adult
chemical_list: D005419:Flavonoids; D020719:Glucuronides; D007783:Lactones; D013463:Sulfuric Acid Esters; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; C057580:gallocatechol; C037556:gamma-valerolactone