Granatumins A−G, Limonoids from the Seeds of a Krishna Mangrove, Xylocarpus granatum

Seven new limonoids (1−7), named granatumins A−G, were isolated from seeds of an Indian mangrove (Xylocarpus granatum) collected from the wetlands of Krishna estuary, Andhra Pradesh. The known compounds khayasin T, tigloylseneganolide A, 6-deoxyswietenine, swietemahonolide, febrifugin A, gedunin, xylogranatinin, phaseic acid, (2R,3R)-3,4′,5,7-tetrahydroxyflavanone, and (E)-4-hydroxycinnamic acid were also isolated. The structures were established on the basis of spectroscopic data. Granatumins A and B are mexicanolides with endo-conjugated Δ^8,30 and Δ^14,15 double bonds, and granatumins F and G are polyhydroxylated phragmalins found previously in plants of the Meliaceae. Khayasin T exhibited moderate insecticidal activity against fifth instar larvae of Brontispa longissima (Gestro) at a concentration of 20 mg/L.