Novel Acetogenins from the Leaves ofAnnona purpurea

The CH2Cl2 extract of the leaves Annona purpurea L. (Annonaceae) showed strong brine shrimp toxicity and pronounced activity against larvae of the yellow-fever mosquito Aedes aegypti. Activity-directed fractionation of the extract by a combination of column chromatography on silica gel, filtration, and high-pressure liquid chromatography led to the isolation of acetogenins 1–6 as the main active principles. The structures of two novel acetogenins named purpureacin 1(5) and purpureacin 2(6) were elucidated by spectroscopic analysis (UV, EI- and DCI-MS, EI-MS of Me3Si derivatives,1H- and 13C-NMR). The configuration of 5 and 6 was not established due to the limited sample amount. Compounds 3–6 also showed antifungal activity against Candida albicans, and 5 was slightly active against Bacillus subtilis.