ABSORPTION AND DISTRIBUTION OF TEA CATECHIN, (-)-EPIGALLOCATECHIN-3-GALLATE, IN THE RAT

To investigate the absorption and metabolism of an anticarcinogenic te a catechin, (-)-epigallocatechin-3-gallate (EGCg), in rats, a newly de veloped chemiluminescence-detection high-performance liquid chromatogr aphy (CL-HPLC) method was employed and the EGCg concentrations in bloo d plasma, liver, brain, small intestinal mucosa and colon mucosa were determined before and after EGCg administration. The recovery of EGCg, extracted consecutively with ethyl acetate and methanol, was 86.1% fr om plasma and 64.5-74.2% from the tissue samples. The EGCg concentrati ons of plasma and tissue samples from the control rat (before EGCg adm inistration) were all below the detection limit (<0.002 nmol/mL, 0.002 nmol/g), but 60 min after a single oral administration of EGCg (500 m g/kg body weight), the levels increased, reaching 12.3 nmol/ml in plas ma, 48.4 nmol/g in liver, 0.5 nmol/g in brain, 565 nmol/g in small int estinal mucosa and 68.6 nmol/g in colon mucosa. The EGCg levels found in the tissues corresponded to 0.0003-0.45% of ingested EGCg. The resu lts indicate that tea catechin, EGCg, is absorbed from the digestive t ract, with the intestinal mucosa the most enriched of the organelles. This may explain the potent antioxidant function of EGCg in inhibiting colon mucosal phospholipid hydroperoxidation in the prevention of rat colonic carcinogenesis.