Absorption, metabolism and excretion of Choladi green tea flavan-3-ols by humans

Stalmach, A. , Troufflard, S., Serafini, M. and Crozier, A. (2009) Absorption, metabolism and excretion of Choladi green tea flavan-3-ols by humans. Molecular Nutrition and Food Research, 53(S1), pp. 44-53. (doi: 10.1002/mnfr.200800169)

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Publisher's URL: http://dx.doi.org/10.1002/mnfr.200800169


Ten healthy human subjects consumed 500 ml of choladi green tea, containing 648 ┬Ámol 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 <i>O</i>-methylated, sulphated and glucuronide conjugates of (epi)catechin and (epi)gallocatechin, with 29-126 nM peak plasma concentrations (c<sub>max</sub>) 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<sub>max</sub> 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<sub>max</sub> values are not an accurate quantitative indicator of the extent to which absorption occurs.

Item Type:Articles
Keywords:Flavan-3-ols, Glucuronide, Green tea, Methyl, Urinary excretion
Glasgow Author(s) Enlighten ID:Stalmach, Dr Angelique and Crozier, Professor Alan
Authors: Stalmach, A., Troufflard, S., Serafini, M., and Crozier, A.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
Q Science > QH Natural history > QH301 Biology
College/School:College of Medical Veterinary and Life Sciences
Journal Name:Molecular Nutrition and Food Research
ISSN (Online):1613-4133
Published Online:31 October 2008

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