NOVEL ACETOGENINS FROM THE LEAVES OF DASYMASCHALON SOOTEPENSE

The hexane extract from the leaves of Dasymaschalon sootepense CRAIB ( Annonaceae) showed strong cytotoxic activity against the L1210 tumor c ell line. Activity-directed fractionation of the extract by column chr omatography on silica gel and high-pressure liquid chromatography led to the isolation of the acetogenins 1-4 as the main active principles. The structures of the two novel structures named sootepensin A (1) an d sootepensin B (2) were elucidated by spectroscopic analysis (UV, EI- and ESI-MS, 1D- and 2D-H-1- and C-13-NMR). The absolute configuration s were established by 2D-NMR experiments utilizing Mosher esters. Two recently described compounds, tonkinin C (3) and tonkinesin C (4), wer e also isolated and are new to the genus Dasymaschalon. All four aceto genins were found to be highly cytotoxic against the L1210 tumor cell line.