| Abstract |
The use of Thai medicinal plants as alternative medicines for prevention or treatment of illness has been increasing in recent years. The aim of the present study was to determine the inhibitory effects of Thai medicinal plants on the activities of human cytochrome P450 and UDP-glucuronosyltransferase in order to predict potential herb-drug interactions. Phenacetin O-deethylase, dextromethorphan O-demethylase, chlorzoxazone 6-hydroxylase, testosterone 6b-hydroxylase, AZT and SN38 glucuronosyltransferase activities in human liver microsomes were measured by HPLC as a selective marker of CYP1A2, CYP2D6, CYP2E1, CYP3A4, UGT2B7 and UGT1A1, respectively. The inhibitory effects of ethanolic and aqueous extracts of 13 commonly used Thai medicinal plants were determined. Among 13 Thai medicinal plants, the ethanolic extract of K. parviflora showed strong inhibition toward CYP1A2 with an IC50 value 0.2 mg/mL. The ethanolic extract of P. amarus was a potent inhibitor of CYP3A4 and CYP2D6 with IC50 values 0.77 and 23 mg/mL, respectively. The ethanolic extract of C. longa showed strong inhibition toward UGT2B7 with an IC50 value 12.9 mg/mL. Collectively, the inhibitory effects varied with the kinds of Thai medicinal plants and CYP or UGT isoforms. We identified some specific constituents in plant extracts, which cause the inhibition. This study revealed that some Thai medicinal plants may cause herb-drug interaction by strong inhibition.
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Publication
Journal Publication
ไทย