BULLACIN - A NEW CYTOTOXIC ANNONACEOUS ACETOGENIN FROM ANNONA-BULLATA

Using the brine shrimp lethality test (BST) to direct fractionation, t wo additional Annonaceous acetogenins, bullacin (1) and parviflorin (2 ), were isolated from the ethanol extract of the bark of Annona bullat a Rich. Their absolute stereochemistries were revealed by the use of M osher's methodology. Compound (1) is a new adjacent bis-tetrahydrofura n (THF) acetogenin possessing a relatively rare C35 skeleton and an un precedented C-6 hydroxyl group. The absolute configuration of 1 was as signed as 6S, 13R, 14R, 17R, 18R, 21R, 22R, and 34S. Compound (2) is a known acetogenin but is new to this plant. The absolute configuration of 2 was concluded to be 4R, 13R, 14R, 17R, 18R, 21R, 22R, and 34S. T his is the first paper in which the absolute stereochemistry of a new acetogenin is published with die new structure. 1 showed 10 to 1000 ti mes the cytotoxic potency of adriamycin when tested in human tumor cel l lines.