British Journal of Nutrition

Research Article

The absorption, metabolism and excretion of flavan-3-ols and procyanidins following the ingestion of a grape seed extract by rats

Catherine Tsanga1, Cyril Augera2a3, William Mullena1, Aurélie Borneta3, Jean-Max Rouaneta2, Alan Croziera1 and Pierre-Louis Teissedrea3 c1

a1 Plant Products & Human Nutrition Group, Graham Kerr Building, Division of Biochemistry & Molecular Biology, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK

a2 Unité Nutrition, GBSA, Place Eugéne Bataillon, Université Montpellier II, 34 095 Montpellier, France

a3 UMR 1083 Sciences Pour l'Œnologie, Centre d'Œnologie, Faculté de Pharmacie, 15, Av. Charles Flahault, BP 14491 Université Montpellier I, 34093 Montpellier cedex 5, France

Abstract

Rats were fed a grape seed extract (GSE) containing (+)-catechin, (−)-epicatechin and dimers, trimers, tetramers and polymeric procyanidins. Liver, kidney, brain and gastrointestinal (GI) tract together with plasma, urine and faeces were collected over a 24 h period and their flavan-3-ol content was analysed by HPLC with tandem mass spectrometry and diode array detection. Small amounts of the GSE flavan-3-ols moved out of the stomach and into the duodenum/jejunum, and to a greater extent the ileum 1 h after ingestion, and into the caecum after 2 h with relatively small amounts being detected in the colon after 3 h. The GI tract contained the parent GSE flavan-3-ols and procyanidins with only trace amounts of metabolites and there were no indications that proanthocyanidins were depolymerised in the GI tract releasing monomeric flavan-3-ols. Plasma contained exclusively catechin glucuronides and methylated glucuronide metabolites which were also detected in the liver and kidneys. These metabolites were also present in urine together with sulphated metabolites and low amounts of the procyanidin dimers B1, B2, B3 and B4 as well as the trimer C2 and an unknown GSE trimer. The amounts of (+)-catechin and (−)-epicatechin metabolites excreted in urine relative to the quantity of the monomers ingested were 27 and 36 %, respectively, after 24 h. This is similar to the levels of urinary excretion reported to occur by other investigators after feeding (−)-epicatechin to rats and provides further, albeit indirect, evidence that the procyanidin oligomers in the GSE were not depolymerised to monomers to any extent after ingestion. No convincing analytical data were obtained for the presence of flavan-3-ol metabolites in the brain.

(Received September 18 2004)

(Revised February 29 2005)

(Accepted May 01 2005)

Correspondence:

c1 *Corresponding author: Dr P.-L. Teissedre, fax +33 (0)4 67 54 86 86, email pteissed@univ-montp1.fr

Footnotes

† Authors made an equal contribution.

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