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 3 0 and 4 0 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 (P¼0 : 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.
Wine: Catechin: Catechin metabolites: Urinary excretion: ManFlavonoids are abundant components of fruits, vegetables, red wine, tea and chocolate (Kühnau, 1976;Scalbert & Williamson, 2000;Arts et al. 2001). They display a multitude of biological effects in vitro and in vivo after consumption of flavonoid-containing foods (Walle et al. 1995;Clifford et al. 1996;So et al. 1996;Teissedre et al. 1996;Da Silva et al. 1998;Nidgikar et al. 1998;Day et al. 2000; Rein et al. 2000a, b;Young et al. 2000;Schramm et al. 2001). Epidemiologic studies show strong associations between consumption of flavonoid-containing foods, especially wine, and reduced mortality from cardiovascular disease (St Leger et al. 1979;Hertog et al. 1993;Klatsky & Armstrong, 1993;Criqui & Ringel, 1994;Sasaki & Kesteloot, 1994;Grønbaek et al. 1995;Hertog et al. 1995;Renaud & de Lorgeril, 1992).Little is known about flavonoid metabolism, distribution and excretion after consumption of common foods. There have been some clinical studies reporting the absorption and excretion of flavonols (Hollman et al. 1995(Hollman et al. , 1997de Vries et al. 1998de Vries et al. , 2001Manach et al. 1998; flavones (Nielsen et al. 1999), anthocyanins (Lapidot et al. 1998, flavanones (Fuhr & Kummert, 1995), flavanols (Lee et al. 1995;Richelle et al. 1999;Rein et al. 2000a) and isoflavonoids (Xu et al. 1994(Xu et al. , 1995Ameer et al. 1996) after consumption from food sources. However, the vast majority of studies were performed using gram-size doses, which gives little insight into the fate of flavonoids when consumed in smaller quantities as food constituents Das & Sothy, 1971;Gugler et al. 1975;Shaw & Griffiths, 1980;Shaw et al. 1982;Hackett et al. 1983;Wermeille et a...