Cytotoxic benzil and coumestan derivatives from Tephrosia calophylla

A benzil, calophione A, 1-(6'-Hydroxy-1',3'-benzodioxol-5'-yl)-2-(6 ''-hydroxy-2 ''-isopropenyl-2 '',3 ''-dihydro-benzofuran-5 ''-yl)-ethane-1,2-dione and three coumestan derivatives, tephcalostan B, C and D were isolated from the roots of Tephrosia calophylla. Their structures were deduced from spectroscopic data, including 2D NMR H-1-H-1 COSY and C-13-H-1 COSY experiments. Compounds were evaluated for cytotoxicity against RAW (mouse macrophage cells) and HT-29 (colon cancer cells) cancer cell lines and antiprotozoal activity against various parasitic protozoa. Calophione A exhibited significant cytotoxicity with IC50 of 5.00 (RAW) and 2.90 mu M (HT-29), respectively. (C) 2008 Published by Elsevier Ltd.