【摘要】 【目的】从苦瓜叶乙醇提取物中分离鉴定活性成分苦瓜素Ⅰ和苦瓜素Ⅱ,测定其对小菜蛾幼虫的拒食和抑制生长发育活性。【方法】用石油醚、乙酸乙酯、正丁醇和水依次对苦瓜叶片乙醇提取物进行萃取,结果发现乙酸乙酯萃取物的拒食活性最强。活性组分经柱层析和高效液相色谱等方法分离纯化,并通过核磁共振谱(NMR)和质谱(MS)鉴定出化合物的分子结构。【结果】苦瓜素Ⅰ和苦瓜素Ⅱ对小菜蛾2、3龄幼虫的取食有明显的抑制作用。其中,苦瓜素Ⅱ的活性最高,对小菜蛾2、3龄幼虫的拒食中浓度(AFC50)分别为76.69μg·ml-1和116.24μg·ml-1。苦瓜素Ⅰ的活性次之,对小菜蛾2、3龄幼虫的AFC50分别为144.08μg·ml-1和168.42μg·ml-1。同时,苦瓜素I和苦瓜素Ⅱ对小菜蛾幼虫体重增长和存活也有抑制作用。【结论】苦瓜素Ⅱ和苦瓜素Ⅰ对小菜蛾幼虫有很强的拒食作用和抑制生长发育的作用,这些化合物的阐明对理解植物与昆虫的相互关系及其对小菜蛾的控制潜力有重要意义。更多还原

【Abstract】 【Objective】From the bioguided fractionation of the ethanol extracts from the leaves of M. charantia, we obtained two most active compounds against the feeding of the diamondback moth, Plutella xylostella larvae. The antifeedant activity of momordicineⅠ and momordicineⅡ against the second and the third instar larvae of Plutella xylostella was tested using leaf discs of cabbage in the laboratory. 【Method】 A range of different solvents, including petroleum ether, ethyl acetate, n-butanol and water, were used to isolation ethanol extract from leaves of M. charantia. Bioassays were then conducted with these fractions to determine their impact on feeding of P. xylostella larvae, The ethyl acetate fractions had significantly impacts on feeding of P. xylostella larvae. The active fractions obtained by column chromatography were purified by high-performance liquid chromatography. Each compound isolated was identified by NMR, MS, and IR spectra.【Result】The results showed that Momordicin I and MomordicinⅡ had significant antifeedant activity on the larvae of P. xylostella, and MomordicinⅡ was more active than MomordicinⅠ. The concentrations for 50% antifeedant effects (AFC50 ) of MomordicinⅡ against the second and the third instar larvae of P. xylostella were 76.69 μg·ml-1 and 116.24 μg·ml-1 while that of MomordicinⅠ was 144.08 μg·ml-1and 168.42 μg·ml-1 respectively. In addition, MomordicinⅠand MomordicinⅡ had significant inhibitive effect on the rate of weight gain and survival of P. xylostella larvae. 【Conclusion】 Momordicin I and MomordicinⅡ had significant antifeedant activity and inhibitive development activity on the larvae of P. xylostella The elucidation of these chemicals is important not only for undestanding the insect-plant relatinships, but also for their potential in P. xylostella control.更多还原