Two new benzofurans from Gastrodia elata and their DNA topoisomerases I and II inhibitory activities.

Two new benzofurans, 1-furan-2-yl-2-(4-hydroxyphenyl)-ethanone (1) and 5-(4-hydroxybenzyloxymethyl)-furan-2-carbaldehyde (2), together with five known compounds, 4-hydroxybenzyl methyl ether (3), 5-(hydroxymethyl)-furfural (4), gastrodin (5), beta-sitosterol (6) and beta-sitosterol glucoside (7) were isolated from the rhizome of Gastrodia elata Blume. In DNA topoisomerase I and II inhibition assays in vitro at a concentration of 20 microM, 1 showed potent inhibitory activity, 66% and 71% inhibition, respectively, compared to the positive control compounds, camptothecin and etoposide, 71% and 22% inhibition, respectively. All of these compounds exhibited weak or no cytotoxicities against human colon carcinoma cell line (HT-29), human breast carcinoma cell line (MCF-7) and human hepatocellular carcinoma cell line (HepG-2).