Six new phragmalins, moluccensins H-M (1-6), two new andirobin-type limonoids, 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 ,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 ∆ 8,9 and ∆ 14,15 double bonds, moluccensins K and L contain a ∆ 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. ]decane ring systems. The family Meliaceae has proved to produce a variety of antifeedant limonoids, such as azadirachtin 3 from the neem tree, Azadiracha indica, and harrisonin 4 from Harrisonnia abyssinica. Two meliaceous mangroves, Xylocarpus granatum and X. moluccensis, are known for producing antifeedant limonoids, especially phragmalins and mexicanolides. Previous investigations on seeds of these two species yielded an andirobin, two phragmalins, three gedunins, and 14 mexicanolides, including xyloccensins A-K.
5-9Previously we have reported the isolation and identification of eight unique 8,9,30-phragmalin ortho esters and 13 limonoids with a new carbon skeleton from the bark and seeds of a Chinese mangrove, X. granatum. [10][11][12] To date, 42 mexicanolides and 23 phragmalins, including three 1,8,9-phragmalin ortho esters, eight 8,9,30-phragmalin ortho esters, and 12 polyhydroxylated phragmalins, have been isolated from the wood, seeds, and fruits of X. granatum and X. moluccensis. 13 We recently identified seven phragmalins, moluccensins A-G, 14 from seeds of an Indian mangrove, X. moluccensis, collected in the mangrove wetlands of Krishna estuary, AndhraPradesh. In the current paper, we present the isolation and characterization of five additional phragmalins (1-5), each with a C-30 carbonyl group, and a unique ring-D-opened 16-norphragmalin (6), from seeds of the same Indian mangrove, X. moluccensis (Lam.) M Roem. (Meliaceae), together with two new andirobin-type limonoids (7, 8), two new tirucallane derivatives (9, 10), and the known compound 3 , 22S-dihydroxytirucalla-7,24-dien-23-one. 15 The structures of these compounds were established on the basis of spectroscopic data or comparison with data in the literature. The new compounds were tested for insecticidal activity against the fifth instar larvae of Brontispa longissima (Gestro) at a concentration of 100 mg/L. (Tables 1 and 2) indicated that nine of the 15 elements of unsaturation came from a conjugated ketone group, four carbon-carbon double bonds, and four ester functionalities. Therefore, the molecule
Results and Discussion