Effect of polymeric black tea polyphenols on benzo(a)pyrene (B(a)P)-induced cytochrome P4501A1 and 1A2 in mice.

摘要

The chemopreventive activity of green tea polyphenols (GTPs) is, in part, due to modulation of cytochrome P450s (CYPs). To investigate the enzyme modulatory properties of major black tea polyphenols, the effect of decaffeinated black tea extract (DBTE) or polymeric black tea polyphenol (PBP) mix was studied on CYP1A1 and CYP1A2 in mouse tissues. Animals receiving 2.5% DBTE or 1% PBP mix or drinking water (15 days) were challenged with single oral benzo(a)pyrene (B(a)P) (1 mg/mouse) treatment on the 14th day. Liver and lung microsomes isolated after 24 h were analysed for CYP1A1 and CYP1A2, using biochemical substrate(s) and Western blot analysis. Treatment with 2.5% DBTE or 1% PBP mix did not significantly alter the basal activity and level of CYP1A1 and CYP1A2, whereas pretreatment with 2.5% DBTE or 1% PBP mix resulted in a significant decrease in both the activity and the level of B(a)P-induced CYP1A1 and CYP1A2 in liver and lungs. The PBP mix possesses enzyme modulatory properties exhibited by monomeric GTPs.