Enzyme-inducing effects of berberine on cytochrome P450 1A2 in vitro and in vivo

Berberine (BER) is an important anti-bacterial drug from Chinese herbal medicine and a novel drug candidate for preclinical development in recent years. Here we provide evidence that the effects of berberine on cytochrome P450 (CYP) 1A2 in vitro and in vivo.Real-time polymerase chain reaction and western blotting analysis were employed to evaluate the CYP1A2 mRNA levels and protein expression. The enzyme activity was assessed by the metabolic rate of phenacetin to acetaminophen by LC-MS/MS method.The results indicated that the CYP1A2 mRNA expression and enzyme activity in HepG2 cells after treated with BER (4.5μg/ml) exhibited a significant induction (16.11-fold and 5.0-fold, respectively), which was consistent with those on rat liver microsomes (4.5-fold and 1.98-fold, respectively) by BER induction (10mg/kg/day, i.p.) ex vivo. Beside, BER induced CYP1A2 activity with increases in AUC0-t and Cmax of acetaminophen and the Ke and t1/2 of phenacetin after oral administration of phenacetin (p<0.05) in vivo.This study firstly reported the induction effect of BER on rats CYP1A2 by intraperitoneal route. But, BER didn't show significant induction effect on CYP1A2 by high-dose orally administrating to rats for 6 consecutive days due to the extremely low bioavailability. The potential drug-drug interactions were supposed to happen when the liver exposed to high dose of BER in vivo by changing administration route.