Glacins A and B: two novel bioactive mono-tetrahydrofuran acetogenins from Annona glabra.

Two new bioactive mono-THF Annonaceous acetogenins, glacins A (1) and B (2), have been isolated, from the fractionated ethanolic extracts of the leaves of Annona glabra, directing the fractionation with the brine shrimp lethality test (BST). The structures of 1 and 2 were elucidated on the basis of 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 several human solid tumor cell lines.