Three new bioactive bis-adjacent THF-ring acetogenins from the bark of Annona squamosa

Continuing work on the bioactivity-directed fractionation of the bark of Annona squamosa has resulted in the discovery of three new Annonaceous acetogenins, (2,4-cis and trans)-squamolinone (1), (2,4-cis and trans)-9-oxoasimicinone (2), and bullacin B (3). Compounds 1-3 are all adjacent bis-THF ring acetogenins with 2 representing the first bis-ring acetogenin to contain a carbonyl along its aliphatic chain. Compound 3 was selectively cytotoxic in a panel of six human tumor cell lines with a potency of nearly a million times that of adriamycin against the MCF-7 (human breast adenocarcinoma) cell line.