18 α-Glycyrrhizic acid down-regulated the activities and mRNA expression of cytochrome P450 isoenzymes in rat hepatocyte sandwich cultures / 中国药理学与毒理学杂志

ABSTRACT

To study the effect and mechanisms of 18 α-glycyrrhizic acid (18 α-GA) on cytochrome P450 (CYP) enzymes, the expression of CYP1A1, CYP2E1 and CYP3A was determined in rat hepatocyte sandwich cultures by using enzyme assay and semi-quantitative reverse transcriptase-polymerase chain reaction(RT-PCR). The results showed that the activities of CYP1A1 (7-ethoxyresorufin O-deethylase, EROD), CYP2E1(aniline hydroxylase, ANH) and CYP3A (erythromycin N-demethylase, ERD) were decreased in concentration-dependent manner after treatment with 18 α-GA(50－400 mg*L-1), and at the concentration of 200 mg*L-1 inhibitory rate reached the maximum (the maximum inhibitory rate was 59.6%, 69.7% and 44.7%, respectively). The time course revealed that the inhibition reached plateau level at d 4 of culure. 18 α-GA Decreased CYP1A1, CYP2E1 and CYP3A1 mRNA expression in dose-dependent manner, the maximum inhibitory rate was 44.5% , 58.1% and 37.1%, respectively. The results suggest that 18 α-GA down-regulate CYP expression at the transcriptive levels.