Effects Of Total Saikosaponins On Several Drug Metabolizing Enzymes And Transporter (P-glycoprotein) In Mice

ObjectiveTo investigate the effects of total Saikosaponins on main Cytochrome450members (Cyp3a, Cyp2d22, Cyp2el and Cypla2) in liver microsome, SulfotransferaselAl (SULT1A1) in liver cytosol and intestinal P-glycoprotein (P-gp) activities and their mRNA expression level in mice.MethodsSPF grade mice were divided into seven groups randomly and each group has five male and female respectively. There has control group (10mL-kg-1), Ketoconazole group (1.8mg-kg-1), Rifampin group (40mg-kg-1), total Saikosaponins groups with high, medium, low and usual dosage (150mg-kg-、75mg-kg-1、15mg-kg-1、3mg-kg-1). Mice were orally administratered with water or investigated samples for seven days. In experimental day, each mouse was treated with APAP (50mg/kg) orally and killed by decapitation60min later, the livers and intestines were acquired quickly at low temperature. Serum APAP concentration was drtermined by spectrophotometer. Liver and intestinal microsomes and cytosol were prepared by differential centrifugation, microsomal and cytosolic protein were quantified by Folin phenolic method, the activities of Cyp3a, Cyp2el and SULT1A1were detected by spectrophotometry, Cyp2d22and Cypla2activities were assayed by HPLC method; Preparation intestinal homogenates, determined P-gp coupled ATP enzyme activity; Used TRIZOL reagent isolated total RNA from mice liver, the expression of Cyp3all, Cyp2d22, Cyp2e1, SULT1A1and Abcblb mRNA were estimated by RT-PCR.ResultsSerum APAP concentration and P-glycoprotein coupled ATPase activities have no significant differences between all saikosaponin groups and control group (P>0.05); Cyp3a activities of high-dosage group (150mg-kg-1) both in liver and intestinal microsomes, erythromycin and aminopyrine as the substrate, were significantly higher than control group (P<0.05), hepatic Cyp2e1and Cyp2d22activities in high-dosage group (150mg-kg-1) and medium dosage group (75mg·kg-1) were obviously lower than control group (P<0.05or P<0.01); hepatic Cypla2activity in high-dosage group (150mg-kg-1) was dramatically lower than control group (P<0.01), however, Cyp1a2activities in low (15mg-kg-1) and usual (3mg-kg-1) dosage groups are greatly increased compared with control group(P<0.01); when we use2-naphthol as substrate to detect SULT1A1activity in liver cytosol, the activities in high dosage (150mg-kg-1) and low dosage (15mg-kg-1) group were seriously higher than control group both in pH5.5and pH6.5reaction system, meanwhile, use4-nitrophenol as substrate, the activities only in high dosage (150mg-kg-1) group were seriously increased in both reaction system, RT-PCR results indicate that only high doses of saikosaponins (150mg-kg-1) can induce the expression of Cyp3all and SULT1A1in the liver.ConclusionTotal saikosaponins can induce Cyp3a activity in mouse liver and intestine and inhibit Cyp2el and Cyp2d22activities in liver; interestingly, TSS could induce Cypla2activity at lower dosage while inhibit its activity obviously at high dosage; TSS also can increase SULT1A1activity in liver but have no influence on P-glycoprotein efflux activity.