Inhibitory potential of three Yin-tonification herbal formulas on the activities of human major cytochrome P450 and UDP- glucuronosyltransferases isozymes in vitro

OBJECTIVE

To investigate the influence of Yin-tonification herbal formulas Jaeumganghwa-tang (Ziyin Jianghuo Tang, JEGHT), Ssanghwa-tang (Shuanghe Tang, SHT) and Yukmijihwang-tang (Liuwei Di huang Tang, YMJHT) on the activities of human major cytochrome P450 (CYP450s) and UDP-glucuronosyltransferases isozymes (UGTs) in vitro.

METHODS

The activities of CYP450s (CYP1A2, CYP3A4, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and CYP2E1) and UGTs (UGT1A1, UGT1A4 and UGT2B7) were assessed using in vitro fluorescence- and luminescence-based enzyme assays, respectively. The effects of herbal formulas on the activities of CYP450s and UGTs were presented as IC50 values.

RESULTS

JEGHT showed the potent inhibition of the CYP2D6 activity, with weak inhibition on the activities of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2E1, CYP3A4, UGT1A1, UGT1A4 and UGT2B7. SHT inhibited the activities of CYP1A2 and CYP2E1, whereas the negligible inhibition of the activities of CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, UGT1A1, UGT1A4 and UGT2B7 through SHT was observed. YMJHT inhibited CYP2E1 activity, with a negligible inhibition on the activities of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, UGT1A1, UGT1A4 and UGT2B7.

CONCLUSION

These findings provide information about the potential interactions between three Yin-tonification herbal formulas and conventional drugs.