Annonacin, a novel, biologically active polyketide from Annona densicoma

A new linear polyketide, Annonacin (I), has been isolated from active extracts of the stembark of Annona densicoma Mart. Annonacin (I) is highly cytotoxic and is active in an assay designed to detect antimitotic agents. The structure of (I) was determined by analysis of spectroscopic data.