Screening of Eleven Commonly Used Traditional Chinese Medicines for Inhibitory Effects on Human Cytochrome P450 Enzymes

Abstract Objective Traditional Chinese medicines (TCMs) as natural therapeutic agents have been widely used and received great attention over the world. However, the information on them to cause herb-drug interactions mediated by cytochrome P450 (CYP) enzymes is limited. The present study aims to evaluate the inhibitory effects of 11 commonly used TCMs, including Nelumbinis Folium, Ginseng Radix et Rhizoma, Ziziphi Spinosae Semen, Chrysanthemi Flos, Lonicera Japonica Flos, Lycii Fructus, Cassiae Semen, Poria, Crataegi Fructus, Schisandrae Chinensis Fructus , and Polygonati Rhizoma , on the five human major CYP isoenzymes 2C19, 2D6, 3A4, 2E1, and 2C9. Methods An in vitro cocktail method was used. Results The aqueous extracts of all tested TCMs were found no significant inhibitory effect, with IC50 values higher than 100 μg/mL. While, the ethanolic extracts of some herbs showed more potent inhibition. These herbs include Nelumbinis Folium with IC 50 values of 12.05 and 61.43 μg/mL on CYP2D6 and CYP2E1, Schisandrae Chinensis Fructus with IC50 values of 64.42 and 47.24 μg/mL on CYP2C19 and CYP3A4, and Chrysanthemi Flos with IC50 values of 45.25 μg/mL on CYP2C9, respectively. Conclusion Co-administration of these TCMs and their products with conventional medicines should be paid much attention to, and their potential inhibitory effects on CYP enzyme activities need to be further investigated.