Hepatoprotective Compounds of the Roots of Cudrania tricuspidata on Tacrine-Induced Cytotoxicity in Hep G2 Cells

The bioassay-guided fractionation of the MeOH extract of the root barks of Cudrania tricuspidata furnished three hepatoprotective compounds, gerontoxanthone A (2), cudraflavone B (4), gericudranin E (5), together with four prenylated xanthones, cudraxanthone B (3), isocudraxanthone K (6), cudraxanthone C (7), cudraxanthone H (8), and a prenylated flavanone, euchrestaflavanone C (1). Compounds 4 and 5 showed significant hepatoprotective effects with the EC50 values of 37.39±0.4 and 39.87±0.7 μM, respectively, and compound 2 showed moderate hepatoprotective effect with an EC50 value of 125.9±1.5 μM, against tacrine-induced cytotoxicity in Hep G2 cells. Silybin as positive control showed an EC50 value of 84.76±0.5 μM. Isocudraxanthone K (6) is a new compound.