title: Dose-response plasma appearance of green tea catechins in adults.
abstract: METHODS
  Tea is an infusion of the Camellia sinensis leaves. The most prevalent bioactive compounds in green tea are catechins (C), which are of great interest for their potential health-promoting effects. However, metabolism and bioavailability of C are not fully understood.
  
  
  RESULTS
  This study investigates the human bioavailability (plasma appearance) of C after drinking three doses of infused green tea in a randomized cross-over design. The sum of area under the curve increased between the small (0.75% w/v, 180 mg total C) and medium (1.25%) dose of ingested green tea but not between the medium and the high (1.75%) dose. The overall pattern for the sum of C did not reflect the fate of individual C. While (-)-epigallocatechin and 4'-O-Me-epigallocatechin showed saturation in plasma between the medium and high green tea doses, (-)-epigallocatechin gallate and (-)-epicatechin did not "saturate" and increased proportionally with the ingested dose. Regardless of the dose, C appeared rapidly in plasma as monophasic curves, suggesting absorption in the small intestine and minimal entero-hepatic circulation.
  
  
  CONCLUSIONS
  As a conclusion, when studying dose response of polyphenols and metabolites, one must look not only at the overall pattern of plasma appearance, but also at data specific for each metabolite.
authors.affiliation: Nestlé Research Center, Nestec Ltd., Lausanne, Switzerland. mathieu.renouf@rdls.nestle.com
authors.forename: Mathieu
authors.initials: M
authors.lastname: Renouf
authors.forename: Cynthia
authors.initials: C
authors.lastname: Marmet
authors.forename: Philippe A
authors.initials: PA
authors.lastname: Guy
authors.forename: Maurice
authors.initials: M
authors.lastname: Beaumont
authors.forename: Mélissa
authors.initials: M
authors.lastname: Lepage
authors.forename: Gary
authors.initials: G
authors.lastname: Williamson
authors.forename: Fabiola
authors.initials: F
authors.lastname: Dionisi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001682:Biological Availability; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D002853:Chromatography, Liquid; D018592:Cross-Over Studies; D004764:Enterohepatic Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018515:Plant Leaves / Q000737:chemistry; D053719:Tandem Mass Spectrometry; D013662:Tea / Q000737:chemistry*; D055815:Young Adult
chemical_list: D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate