New cytotoxic 6-oxygenated 8,9-dihydrofurocoumarins, hedyotiscone A-C, from Hedyotis biflora

Using the bioactivity-guided fractionation method, three new 6-oxygenated 8,9-dihydrofurocoumarin-type compounds, hedyotiscones A (1), B (2), and C (3) were isolated from the methanol extract of Hedyotis biflora together with seven known compounds. The structures of all isolated compounds were determined on the basis of mass and spectroscopic evidence. Compounds 1-3, oleanolic acid, and 6'-(beta-sitosteryl-3-O-beta-D-glucopyranosidyl) pentadecanoate showed marginal cytotoxicity against Hep G2 cells (human liver cancer cells) with IC50 values of 14.4, 17.4, 4.9, 8.0, and 9.2 mu g/mL, respectively. Ursolic acid showed significant cytotoxicity against MDA-MB-231 cells (human breast carcinoma cells) with an IC50 value of 1.49 mu g/mL.