Mexicanolides from the seeds of a Krishna mangrove, Xylocarpus moluccensis

Two new mexicanolides, named xylomexicanolides A and B, were isolated from the seeds of an Indian mangrove, Xylocarpus moluccensis, together with four known limonoids, khayasin, angolensic acid methyl ester, khayasin T, and 2'S-methylbutanoylproceranolide. The structures of these limonoids were established on the basis of spectroscopic data. The (13)C-NMR data of khayasin were reported for the first time. Khayasin was found to exhibit marked insecticidal activity against the fifth instar larvae of Brontispa longissima (GESTRO) at a concentration of 10 mg/l.