49(P-17) アフリカ薬用植物由来の新規リモノイドの構造(ポスター発表の部)

概要

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The origin of secondary metabolites in plant is a response to the pressures of natural selection during the coevolution of plant and insect. A number of deterrent chemicals occur in high concentrations in plant and, in certain case, are believed to reduce insect predation. The efficacy of phytomedicines in affecting human is rooted in the similarity of the primary metabolism of insect and higher animal. Hence, often-documented sources of medicinal plant may also serve as sources of potent insecticidal agent beneficial in agriculture as well as effective food additive and medicine. During our continuing study of biologically active substance from African medicinal plants at this prospect, three novel A-seco limonoids were isolated from methanolic extract of Croton jatrophoides and designated as zumsin (1), dumnin (2), and dumsenin (3). These compounds showed potent antifeedant activity (PC_<50>≦2.0μg/mL) against two lepidopteran larvae, pink bollworm, Pectinophora gossypiella and fall armyworm, Spodoptera frugiperda. The structures were determined by a variety of spectroscopic experiments including nuclear magnetic resonance and mass spectrometry. Interestingly, limonoid 1 consists of an A'-B trans-fused ring whereas 2 and 3 maintain A'-B cis-fused ring, suggesting that, after A ring oxidative expansion, two different biosynthetic processes take place in C. jatrophoides.
天然有機化合物討論会の論文
2004-10-01