Limonoids from the seeds of a Godavari mangrove, Xylocarpus moluccensis.
ABSTRACT Ten limonoids, named godavarins A-J (1-7, 9-11), were isolated from seeds of an Indian mangrove (Xylocarpus moluccensis) collected in the mangrove wetlands of Godavari estuary, Andhra Pradesh. Eight known limonoids, viz. xyloccensins L (8), P (12), Q (13), mexicanolide (14), 6-deoxy-3-detigloyl-swietenine acetate (15), fissinolide (16), methyl 3β-acetoxy-1-oxomeliaca-8(30),14-dienoate (17), and methyl 3β-acetoxy-1-oxomeliaca-8(9),14-dienoate (18), were also obtained. The structures of these compounds were established on the basis of spectroscopic data or comparison with data in the literature (known compounds). The stereostructure of godavarin D was confirmed by means of single-crystal X-ray analysis. Godavarins A-C are the first mexicanolide derivatives with a C₇-C₂₈ ester-linked δ-lactone ring, while godavarins D-G are further additions to the small group of limonoids with a C₁-C₂₉ oxygen bridge. Godavarin H is a phragmalin with five acetoxy groups. Two limonoids, mexicanolide and fissinolide, were found to exhibit marked antifeedant activity against the third-instar larvae of Brontispa longissima (Gestro) at a concentration of 0.5 mg/mL. The most potent compound was mexicanolide. It also showed moderate insecticidal activity.
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ABSTRACT: Thirteen limonoids with a new carbon skeleton, the xylogranatins F-R (1-13), have been isolated from the seeds of a Chinese mangrove, Xylocarpus granatum; two recently reported compounds, xylogranatins C and D were also isolated. Their structures were elucidated on the basis of spectroscopic data and chemical methods. The absolute configurations of these compounds were determined by using the modified Mosher MTPA ester method and by quantum chemical circular dichroism (CD) calculations. Xylogranatins F-Q are the first aromatic B-ring limonoids found in nature. They belong to two substructural classes, of which one (1-3) contains a pyridine ring while the other one (4-12) contains a central furan core. Xylogranatins C and R can be considered to be key biosynthetic intermediates, while xylogranatin D, the only limonoid found so far with a carbon skeleton that conatains a C(30)-C(9) linkage, is apparently an artifact. The structures of these compounds suggest a new biogenetic pathway to tetranortriterpenoids. Xylogranatins F, G and R were found to exhibit marked antifeedant activity against the third instar larvae of Mythimna separata (Walker) at a concentration of 1 mg mL(-1). The most potent compound tested was xylogranatin G. Its AFC(50) (concentration for 50 % antifeedant activity) values at the exposure times of 24 and 48 h were 0.31 and 0.30 mg mL(-1), respectively.Chemistry 02/2008; 14(4):1129-44. · 5.83 Impact Factor
- ChemInform 01/2007; 38(31).
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ABSTRACT: Fifteen B,D-secolimonoids of mexicanolide, rearranged phragmalin, methyl angolensate and glycoside types have been isolated from ether and acetone extracts of the stem bark of Khaya senegalensis (Desr.). The antifeedant activity of the isolated compounds was assessed by conventional choice leaf disc method on the third-instar larvae of Spodoptera littoralis (Boisd.). Khayalactol, 1-O-acetylkhayanolide A, 2-hydroxyseneganolide, khayanolide A, khayanolide D and methyl angolensate displayed strong antifeedant activity at 1000 μg/ml with antifeedant percentages of 83.8, 61.9, 60.1, 59.5, 57.1 and 55.7, respectively. 2-Hydroxyseneganolide and khayanolide D showed high activity at 500, 300 and 200 μg/ml while 1-O-acetylkhayanolide A was the only compound that revealed antifeedant activity at a concentration as low as 100 μg/ml. Antifeedant activity was dose-dependent in some of the isolated compounds. Correlation between antifeedant activity of the isolated compounds and chemical structure was discussed.Journal of Applied Entomology 04/2003; 127(4):236 - 239. · 1.56 Impact Factor