RESUMO
Three anthraquinones (1, 2 and 4), three stilbenes (5, 6 and 7) and 3,5-dihydroxybenzyl alcohol (3) were isolated from Reynoutria japonica. Their structures were identified as emodin (1), emodin-8-O-ß-D-glucoside (2), 3,5-dihydroxybenzyl alcohol (3), citreorosein (4), cis-resveratrol (5), trans-resveratrol (6) and trans-resveratrol-5-O-ß-D-glucopyranoside (7) by comparing their physicochemical and spectral data with published data. Compound 3 was isolated for the first time from the Polygonaceae family. Among the purified compounds, 3 showed more potent inhibitory activity against topoisomerase I (IC50: 4 µM) than camptothecin, as the positive control (IC50: 18 µM). Compounds 3, 4, 5, 6 and 7 showed stronger inhibitory activities toward DNA topoisomerase II (IC50: 0.54, 14, 15, 0.77 and 3 µM, respectively) than the positive control, etoposide (IC50: 44 µM). Compounds 1 and 4 displayed weak cytotoxicities against human lung cancer (A549), ovarian cancer (SK-OV-3), human liver hepatoblastoma (HepG2) and colon adenocarcinoma (HT-29) cell lines.