(-)-Epigallocatechin-3-gallate (EGCG), has been shown to inhibit cancer in vivo. EGCG, however, is rapidly methylated by catechol-. O-methyl transferase (COMT), which reduces its cancer preventive efficacy. Tolcapone (TOL) is a clinically-used COMT inhibitor. Here, we examined the effect of TOL on the bioavailability of EGCG in male CF-1 mice. Plasma and tissue levels of EGCG and its methyl metabolites were determined following intragastric administration of EGCG (100 mg/kg), TOL (30 mg/kg), or the combination. In mice treated with EGCG, unmethylated plasma EGCG accounted for 63.4% of the total. Co-administration of TOL increased this fraction to 87.9%. In the urine, unmethylated EGCG accounted for 29.2% of the total, whereas treatment with EGCG plus TOL increased this to 81.8%. Similar effects were observed in the major organs examined. TOL effectively inhibited the methylation of EGCG in vivo. Future studies should examine the cancer preventive effects of the combination.
All Science Journal Classification (ASJC) codes
- Food Science
- Medicine (miscellaneous)
- Nutrition and Dietetics