Pterocarpans and isoflavones from the root bark of millettia micans and of millettia dura

Abstract

From the CH2Cl2/CH3OH (1:1) extract of the root bark of Millettia micans, a new pterocarpan, (6aR,11aR)-7,8,9-trimethoxy-3-hydroxypterocarpan (1), named micanspterocarpan, was isolated. Similar investigation of the CH2Cl2/CH3OH (1:1) extract of the root bark of Millettia dura gave a further new pterocarpan, 3-O-prenylmaackiain (2) along with six known isoflavones (3-8) and a chalcone (9). All purified compounds were identified by NMR and MS, and the absolute configuration of 1 was established by quantum chemical CD calculation. The isolated constituents, calopogonium isoflavone B (3) and isoerythrin A-4'(3-methylbut-2-enyl) ether (4) showed marginal activities against the 3D7 and the Dd2 strains of Plasmodium falciparum (70-90% inhibition at 40 M). Maximaisoflavone B (5) and 7,2'-dimethoxy-4',5'methylenedioxyisoflavone (7) were weakly cytotoxic (IC50 153.5 and 174.1 M, respectively) against the MDB-MB-231 human breast cancer cell line. None of the tested compounds showed toxicity against the HEK-293 human embryonic kidney cell line at 40 M.