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 cell line. Activity-directed fractionation of the extract by column chromatography 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 ) and sootepensin B ( 2 ) were elucidated by spectroscopic analysis (UV, EI- and ESI-MS, 1D- and 2D-¹H- and ¹³C-NMR). The absolute configurations were established by 2D-NMR experiments utilizing Mosher esters. Two recently described compounds, tonkinin C ( 3 ) and tonkinesin C ( 4 ), were also isolated and are new to the genus Dasymaschalon. All four acetogenins were found to be highly cytotoxic against the L1210 tumor cell line.