Influence of drug metabolizing enzyme inhibitors on liver injury susceptibility to trans-2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside

By using the drug metabolizing enzyme inhibitors, the effects of metabolic factors on potential liver injury induced by the main component, trans-2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside(trans-SG), in Polygonum multiflorum was investigated. The main metabolic enzyme isoforms involved in trans-SG metabolism were also screened. The results showed that trans-SG at the dosage 31 mg·kg^-1 did not cause liver injury; and the combination of trans-SG with the phase I metabolic enzyme inhibitor, 1-benzylimidazole (10 mg·kg^-1), did not change the degree of liver injury(compared with LPS + trans-SG group, P > 0.05). However, the combination of trans-SG with phase II metabolic enzyme inhibitor, ketoconazole(35 mg·kg^-1), significantly increased the degree of liver injury(compared with LPS + trans-SG group, P < 0.05). The phase I metabolites of trans-SG were not detected in human liver microsomes phase I metabolism system, while the phase II trans-SG metabolites were detected in recombinant human UGT isozymes phase II metabolism system. Six isoforms of uridine diphosphate glucuronate transferase(UGT)exhibited abilities to metabolize trans-SG and the order of metabolic ability was: UGT1A1 > UGT1A9 > UGT1A7 > UGT1A10 > UGT2B7 > UGT1A8. The results showed that trans-SG was mainly metabolized by UGT in phase II metabolism. The inhibition of drug metabolizing enzymes of phase II can increase the liver injury susceptibility of trans-SG, which provides a reference to the evaluation of susceptible factors and drug incompatibility research of Polygonum multiflorum.