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Absorption, metabolism and excretion of Choladi green tea flavan‐3‐ols by humans
Author(s) -
Stalmach Angélique,
Troufflard Stéphanie,
Serafini Mauro,
Crozier Alan
Publication year - 2009
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200800169
Subject(s) - catechin , chemistry , ingestion , metabolite , urine , excretion , flavan , bioavailability , glucuronide , absorption (acoustics) , metabolism , food science , chromatography , high performance liquid chromatography , biochemistry , polyphenol , stereochemistry , pharmacology , biology , antioxidant , physics , acoustics
Ten healthy human subjects consumed 500 mL of Choladi green tea, containing 648 μmol of flavan‐3‐ols after which plasma and urine were collected over a 24 h period and analysed by HPLC‐MS. Plasma contained a total of ten metabolites, in the form of O ‐methylated, sulphated and glucuronide conjugates of (epi)catechin and (epi)gallocatechin, with 29–126 nM peak plasma concentrations ( C max ) occurring 1.6–2.3 h after ingestion, indicative of absorption in the small intestine. Plasma also contained unmetabolised (–)‐epigallocatechin‐3‐gallate and (–)‐epicatechin‐3‐gallate with respective C max values of 55 and 25 nM. Urine excreted 0–24 h after consumption of green tea contained 15 metabolites of (epi)catechin and (epi)gallocatechin, but (–)‐epigallocatechin‐3‐gallate and (–)‐epicatechin‐3‐gallate were not detected. Overall flavan‐3‐ol metabolite excretion was equivalent to 8.1% of intake, however, urinary (epi)gallocatechin metabolites corresponded to 11.4% of (epi)gallocatechin ingestion while (epi)catechin metabolites were detected in amounts equivalent to 28.5% of (epi)catechin intake. These findings imply that (epi)catechins are highly bioavailable, being absorbed and excreted to a much greater extent than most other flavonoids. It is also evident that flavan‐3‐ol metabolites are rapidly turned over in the circulatory system and as a consequence C max values are not an accurate quantitative indicator of the extent to which absorption occurs.