AN ANTIMITOTIC AND CYTOTOXIC CHALCONE FROM FISSISTIGMA-LANUGINOSUM

Bioassay-guided fractionation of an ethyl acetate extract of Fissistig ma lanuginosum led to the isolation of the known chalcone pedicin [1], which inhibited tubulin assembly into microtubules (IC50 value of 300 mu M). From the same EtOAc fraction, two new condensed chalcones, fis sistin [2] and isofissistin [3], which showed cycotoxicity against KB cells, were also obtained, together with the inactive dihydropedicin [ 4] and 6,7-dimethoxy-5,8-dihydroxyflavone [5] In addition, the aminoqu inones 6, 8, and 9 were isolated from the alkaloid extract. These comp ounds were artifacts, prepared by treatment of 1, 4, and 2, respective ly, with NH4OH. The structures of the new compounds were elucidated by spectral methods, especially 2D nmr.