title: Updated bioavailability and 48 h excretion profile of flavan-3-ols from green tea in humans.
abstract: Green tea is a popular beverage, prepared with infusion of unfermented dried leaves of Camellia sinensis, and is one of the most relevant sources of polyphenolic compounds in the human diet. This study reports green tea flavan-3-ol absorption, metabolism and complete urinary excretion up to 48 h in 20 healthy volunteers. Urinary and tea samples were analysed by high-performance liquid chromatography coupled with tandem mass spectrometry. Green tea contained monomeric flavan-3-ols and proanthocyanidins with a total polyphenol content of 728 μmol. A total of 41 metabolites were identified in urines, all present in conjugated forms. Among these, six colonic metabolites of green tea flavan-3-ols were identified for the first time after green tea consumption in humans. The average 48 h bioavailability was close to 62%, major contributors being microbial metabolites. Some volunteer showed a 100% absorption/excretion, whereas some others were unable to efficiently absorb/excrete this class of flavonoids. This suggests that colonic ring fission metabolism could be relevant in the putative bioactivity of green tea polyphenols.
authors: Human Nutrition Unit, The φ², Laboratory of Phytochemicals in Physiology, Department of Public Health, University of Parma, Parma, Italy.
authors: Luca
authors: L
authors: Calani
authors: Daniele
authors: D
authors: Del Rio
authors: Maria
authors: M
authors: Luisa Callegari
authors: Lorenzo
authors: L
authors: Morelli
authors: Furio
authors: F
authors: Brighenti
mesh_terms: D000328:Adult; D001682:Biological Availability; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives; D003106:Colon / Q000378:metabolism*; D005419:Flavonoids / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D018515:Plant Leaves; D028321:Plant Preparations / Q000378:metabolism / Q000493:pharmacokinetics* / Q000652:urine; D059808:Polyphenols / Q000032:analysis; D044945:Proanthocyanidins / Q000032:analysis; D013662:Tea / Q000737:chemistry*; D055815:Young Adult
chemical_list: D005419:Flavonoids; D028321:Plant Preparations; D059808:Polyphenols; D044945:Proanthocyanidins; D013662:Tea; C404987:flavan-3-ol; D002392:Catechin