Bioactivity-guided isolation of cytotoxic triterpenoids from the trunk of Berberis koreana.

A bioassay-guided fractionation and chemical investigation of the trunk of Berberis koreana resulted in the isolation and characterization of two new triterpenoids, 23-trans-p-coumaroyloxy-2alpha,3alpha-dihydroxyolean-12-en-28-oic acid (1), and 23-cis-p-coumaroyloxy-2alpha,3alpha-dihydroxyolean-12-en-28-oic acid (2), along with seven known triterpenoids (3-9). The structures of the new compounds were determined on the basis of spectroscopic analyses including 2D NMR. The cytotoxic activities of the triterpenes (1-9) were evaluated by determining their inhibitory effects on human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15) using the SRB assay. Compounds 5 and 6 showed potent cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines (IC(50) (5): 4.37, 7.04, 9.72, and 5.83 microM, and IC(50) (6): 5.57, 7.84, 13.29, and 5.61 microM, respectively).