Cytotoxic and DNA Topoisomerases I and II inhibitory constituents from the roots of Aralia cordata

Bioactivity-guided fractionation, based on the DNA topoisomerase inhibitory activity, lead to the isolation of five compounds (1-5) from the methylene chloride extract of the roots of Aralia cordata Thunb. (Araliaceae). These compounds were identified as ent-pimara-8(14),15-dien-19oic acid (1), ent-pimara-8(14),15-dien-18-oic acid (2), 16 alpha-hydrogen-17-isovaleryloxy-ent-kauran-19-oic acid (3), 16 alpha-hydroxy-17-isovaleryloxy-ent-kauran-19-oic acid (4) and dehydrofalcarindiol-8-acetate (5) from their spectral data. Compound 3 was isolated for the first time from this plant, and also showed the strongest inhibition of both DNA topoisomerase I and If activities, with 53 and 96% inhibitions, respectively, at a concentration of 20 mu M. However, all the compounds exhibited either weak or no cytotoxicities against the human colon carcinoma cell line (HT-29), the human breast carcinoma cell line (MCF-7) and human hepato blastoma cell line (HepG-2).