| Abstract
| - The metabolism of grape seed polyphenol (GSP) has been investigated in rats by high-performanceliquid chromatography analysis of the serum and urinary concentrations of the GSP metabolites (+)-catechin (CT), (−)-epicatechin (EC), 3‘-O-methyl-(+)-catechin, and 3‘-O-methyl-(−)-epicatechin. Theserum concentration of these four metabolites reached a maximum 3 h after the oral administrationof GSP. The urinary excretion of these GSP metabolites accounted for 0.254% (w/w) of theadministered dose of GSP (1.0 g/kg), and the majority of these metabolites were excreted within 25h of oral administration. The serum concentration and urinary excretion of these metabolites werealso compared after the oral administration of different GSP monomers (gallic acid, CT, and EC),normal GSP, and the high molecular weight components of GSP (GSPH). No metabolites weredetected in the serum of rats given GSPH. The urinary percentage excretion of the GSP metabolitesderived from the respective monomers (CT or EC) did not vary with the administration of differentsubstances (CT or EC, GSP, or GSPH). Taken together, these results suggest that only the monomersof GSP are absorbed and metabolized. Keywords: Grape seed polyphenol; metabolism; rat; (+)-catechin; (−)-epicatechin; 3‘-O-methyl-(+)-catechin; 3‘-O-methyl-(−)-epicatechin
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