Abstract
Two new annonaceous acetogenins squamocin P (2) and annosquatin III (3) and one new ACG precursor dieporeticenin B (1) along with five known precursors (4–8) were isolated from the seeds of Annona squamosa. Their structures were ascertained by chemical methods and various spectral evidences. These compounds showed inhibitory effects against three multidrug-resistant (MDR) cancer cell lines. Compound 2 and 3 displayed selective cytotoxicity against SMMC 7721/T (IC50 0.435 and 1.79 μM) and MCF-7/ADR (IC50 values 3.34 and 4.04 μM).