Abstract: AIM: To investigate the influence of Quick-Acting Heart Reliever and Tongxinluo capsules on drug metablic enzyme cytochrome P450(CYP450) system in rats. METHODS: Rat liver and intestine microsome were prepared after a ten-day continuous administration of Quick-Acting Heart Reliever and Tongxinluo capsules. The content of total CYP450s in rat liver microsome was measured by UV-visible absorption spectrometry. Meanwhile, the protein expression of CYP1A2, CYP2C11, CYP2E1 and CYP3A in the liver microsome and CYP3A in the small intestine microsome was detected by western blotting assay. RESULTS: No significant difference of total CYP450 content was observed between each treatment group and control group(P>0.05). Western blot analysis showed that Quick-Acting Heart Reliever induced the CYP1A2 in liver microsome, but inhibited the liver CYP2C11 and CYP3A in intestine microsome; Tongxinluo capsules induced the expression of CYP1A2 and CYP2E1 in liver microsome. CONCLUSION: Quick-Acting Heart Reliever and Tongxinluo capsules exhibit induction/inhibition on the expression of CYP450 isoforms. The results suggest that the related possible side effects of drug-drug interaction could not be neglected in the period of clinical therapy.

Key words: Cytochrome P450 (CYP450), Western blotting, Drug interaction