Limonoids and Tirucallane Derivatives from the Seeds of a Krishna Mangrove, Xylocarpus moluccensis

Six new phragmalins, moluccensins H-M (1-6), two new andirobin-type limonoicls, moluccensins N and O(7, 8), and two new tirucallane derivatives, moluccensins P and Q (9, 10), were isolated from seeds of an Indian mangrove, Xylocarpus moluccensis, together with the known compound 3 beta,22S-dihydroxytirucalla-7,24-dien-23-one. The structures of these compounds were established on the basis of spectroscopic data. Moluccensins H-L were phragmalins with a C-30 carbonyl group, and moluccensin M was a unique ring-D-opened 16-norphragmalin. Moluccensins H-J possess conjugated Delta(8,9) and Delta(14,15) double bonds, moluccensins K and L contain a Delta(8,14) double bond, and moluccensin M has a characteristic C(15)-C(30) linked five-membered lactone ring. Moluccensins H and I showed moderate insecticidal activity against the fifth instar larvae of Brontispa longissima (Gestro) at a concentration of 100 mg/L.