The disposition of 3-O-methyl-(+)-catechin in the rat and the marmoset following oral administration.

The tissue distribution of an alkyl substituted flavanol, 3-0-methyl-(+)-catechin, has been investigated. Following oral administration, 3-0-methyl[14C]-(+)-catechin was well absorbed, peak levels of serum radioactivity for three dose levels being recorded within one hour of administration. Despite extensive absorption, it has been demonstrated that over the period 0-24 h after administration much of the radioactivity in the carcasses of rats was associated with the contents of the alimentary canal. This appears to be largely due to the enterohepatic circulation of the major metabolite 3,3'-0-dimethylcatechin glucuronide, since the present study indicates that some 60% of biliary excreted metabolites are reabsorbed in the first enterohepatic circulation. Metabolism of 3-0-methyl-(+)-catechin was rapid since the unchanged compound was detected in serum only at high dose levels and trace amounts only of 3-0-methyl-(+)-catechin were detected in intestinal contents 3 h after dosing. Radiometric examination of tissue samples following 3-0-[14C]methyl-(+)-catechin administration indicated that maximal tissue levels were observed at 30 min. After 6 h only trace amounts were detectable.