New cytotoxic prenylated isoflavonoids from Bituminaria morisiana

Abstract

Using cytotoxicity against KB cancer cells as a lead, bioguided-fractionation of the petroleum ether and Et acetate exts. of Bituminaria morisiana leaves led to the isolation of two new pterocarpans, namely 3,9-dihydroxy-4-(3,3-dimethylallyl) [6aR,11aR]-pterocarpan, 3-hydroxy-4-(3,3-dimethylallyl)-4'',5''-dehydropyrano[8,9:2'',3''][6aR,11aR]-pterocarpan and one new isoflavone identified as 4',5''-dihydroxy-6''-methoxy-4'',4''-dimethyl-4'',5''-dihydro-6''H-pyrano[2'',3'':7,8]-isoflavone. Moreover, two known pterocarpans, erybraedin C and bitucarpin A, three known isoflavones, daidzein, 8-prenyldaidzein and bidwillon C, one known furocoumarin, pseudoisopsoralen and one known coumestan, coumestrol were isolated. The structures of the isolated compds. were established by 1D and 2D NMR spectroscopy, as well as mass spectrometry. Further cytotoxicity tests against cells related to the immune system (Jurkat T, Mono-Mac-6 and polymorphonuclear cells) showed a moderate activity of the known pterocarpan erybraedin C against all cell lines used (IC50 values between 17.6-28.8 micro M). In addn., erybraedin C was found to induce necrosis in leukemia Jurkat T cells.