Two Novel Bioactive Adjacent Bis-THF Acetogenins from the Leaves of Annona glabra

Continuing work on the bioactivity-directed fractionation of the ethanolic extracts of the leaves of Annona glabra has resulted in the discovery of two new bioactive adjacent bis-THF Annonaceous acetogenins, 6-OH desacetyluvaricin (1) and 6-OH 4-deoxysquamotacin (2). The structures of 1 and 2 were elucidated based on spectroscopic and chemical methods, and the absolute stereochemistries were solved by preparing their respective per-Mosher ester derivatives. 1 and 2 showed potent and selective in vitro cytotoxicities among six human solid tumor cell lines.