(-)-Epigallocatechin-3-gallate (EGCG), from green tea (Camellia sinensis), has demonstrated chemopreventive activity in animal models of carcinogenesis. Previously, we reported the bioavailability of EGCG in rats (1.6%) and mice (26.5%). Here, we report that cotreatment with a second dietary component, piperine (from black pepper), enhanced the bioavailability of EGCG in mice. Intragastric coadministration of 163.8 μmol/kg EGCG and 70.2 μmol/kg piperine to male CF-1 mice increased the plasma Cmax and area under the curve (AUC) by 1.3-fold compared to mice treated with EGCG only. Piperine appeared to increase EGCG bioavailability by inhibiting glucuronidation and gastrointestinal transit. Piperine (100 μmol/L) inhibited EGCG glucuronidation in mouse small intestine (by 40%) but not in hepatic microsomes. Piperine (20 μmol/L) also inhibited production of EGCG-3″-glucuronide in human HT-29 colon adenocarcinoma cells. Small intestinal EGCG levels in CF-1 mice following treatment with EGCG alone had a Cmax = 37.50 ± 22.50 nmol/g at 60 min that then decreased to 5.14 ± 1.65 nmol/g at 90 min; however, cotreatment with piperine resulted in a Cmax = 31.60 ± 15.08 nmol/g at 90 min, and levels were maintained above 20 nmol/g until 180 min. This resulted in a significant increase in the small intestine EGCG AUC (4621.80 ± 1958.72 vs. 1686.50 ± 757.07 (nmol/g·min)). EGCG appearance in the colon and the feces of piperine-cotreated mice was slower than in mice treated with EGCG alone. The present study demonstrates the modulation of the EGCG bioavailablity by a second dietary component and illustrates a mechanism for interactions between dietary chemicals.
All Science Journal Classification (ASJC) codes
- Medicine (miscellaneous)
- Nutrition and Dietetics