Beneficial health effects have recently been claimed for pomegranate juice. In 
vitro and in vivo studies have demonstrated its anti-atherosclerotic capacity, 
chemoprevention and chemotherapy of prostate cancer, and antiproliferative, 
apoptotic, and antioxidant activity, among others. On the other hand, there is a 
complex interplay between tumor initiation, promotion, and progression and 
xenobiotic biotranformation. This led us to investigate the effect of 
pomegranate juice consumption on cytochrome P450 (CYP) activity and expression. 
For this purpose, male mice consumed this fruit juice for 4 weeks, and 
pentobarbital-induced sleeping time and total hepatic CYP content, activity, and 
expression were evaluated. Moreover, the activity of CYP isoform 2E1 and 
expression of the main CYP isoforms, namely, CYP1A1/2, CYP2E1, and CYP3A, were 
also assessed. It was found that pomegranate juice consumption decreased total 
hepatic CYP content as well as the expression of CYP1A2 and CYP3A. Prevention of 
procarcinogen activation through CYP activity/expression inhibition may be 
involved in pomegranate juice's effect on tumor initiation, promotion, and 
progression.