Squamotacin: An Annonaceous Acetogenin with Cytotoxic Selectivity for the Human Prostate Tumor Cell Line (PC-3)

Abstract
The bark extracts of Annona squamosa yielded a new bioactive acetogenin, squamotacin (1), and the known compound, molvizarin (2), which is new to this species. Compound 1 is identical to the potent acetogenin, bullatacin (3), except that the adjacent bis-tetrahydrofuran (THF) rings and their flanking hydroxyls are shifted two carbons toward the γ-lactone ring. Compound 1 showed cytotoxic selectively for the human prostate tumor cell line (PC-3), with a potency of over 100 million times that of Adriamycin.