Volume 87, Issue 1, January (2002), pp. 31-37 © The Author 2002
doi:10.1079/BJN2001482

Urinary excretion of catechin metabolites by human subjects after red wine consumption

Jennifer L. Donovan¹*, Sidika Kasim-Karakas², J. Bruce German³ and Andrew L. Waterhouse
Departments of ¹Viticulture and Enology, ²Endocrinology and Metabolism and ³Food Science and Technology, University of California, Davis, California 95616, USA

 (Received 1 May 2001–Revised 25 July 2001–Accepted 31 August 2001)

Little is known about flavonoid metabolism and excretion in man. In the present study, the urinary excretion of a major flavonoid in wine, catechin, and its metabolites, were measured after nine human subjects each consumed 120 ml red wine (RW) on one day and de-alcoholized red wine (DRW) on a separate day. Both the RW and DRW contained 120 (SEM 3) mmol catechin (35 mg). GC–MS analyses of the trimethylsilylated derivatives of catechin and 39 and 49 methylcatechin were performed before and after hydrolysis of conjugates by b-glucuronidase and sulfatase. Baseline urine samples collected prior to wine consumption contained 0·013 (SEM 0·005) mmol catechin and metabolites. During the 8 h period following consumption of RW and DRW, 6·6 (SEM 0·9) and 5·3 (SEM 0·6) mmol catechin and metabolites were excreted in 893 (SEM 94) and 740 (SEM 101) ml urine respectively. This corresponded to 3·0–10·3 % of the dose after RW and 2·1–8·2 % of the dose after DRW. The amount of catechin and metabolites excreted in urine was 20 % higher after RW compared with DRW (P=0·06). Catechin in all urine samples was present as metabolites and there were no differences in the proportions of individual metabolites after RW and DRW. As with other flavonoids, the fate of most ingested catechin is not yet known.

Keywords:
Wine: Catechin: Catechin metabolites: Urinary excretion: Man