Modulatory Effects of Atractylodin and β-Eudesmol on Human Cytochrome P450 Enzymes: Potential Drug-Drug Interactions.

Atractylodin and β-eudesmol, the major bioactive compounds in , are promising candidates for anti-cholangiocarcinoma. The inhibitory effects of both compounds on human rCYP1A2, rCYP2C9, rCYP2C19, rCYP2D6 and rCYP3A4 enzymes were investigated using luminogenic CYP450 kits. The modulatory effects were investigated in mouse livers following a daily oral dose of atractylodin or β-eudesmol at 100 mg/kg body weight for 1, 7, 14, and 21 days. The inhibitory effects of both compounds on all rCYP450s were weak (IC: 167 to >686 µM). β-Eudesmol showed the most potent inhibitory effect on rCYP2C19 (IC = 172.7 µM) and rCYP3A4 (IC = 218.6 µM). Results of the ex vivo study showed that short exposure (1-7 days) of atractylodin and β-eudesmol resulted in the upregulation of mRNA. Prolonged exposure to the daily oral dose for at least 14 days significantly downregulated the expressions of mRNA and proteins, which correlated with the decrease in the activities of mCYP1A2 and mCYP3A11. Based on the results of the ex vivo study, clinical uses of atractylodin or β-eudesmol for the treatment of cholangiocarcinoma are of concern for the risk of toxicity due to hCYP3A4 inhibition following chronic dosing, as well as the metabolic interaction with the coadministered drugs that are metabolized by hCYP3A4.