杠柳的不同溶剂提取分离物对小菜蛾幼虫的拒食和毒杀作用

以生物活性跟踪法测定了杠柳Periploca sepium Bunge 的不同溶剂提取液及其不同馏份对小菜蛾幼虫的拒食和毒杀活性。结果表明,杠柳根皮的乙醇提取液和氯仿提取液对小菜蛾具有较强的拒食和毒杀活性,该生物活性高于石油醚提取液。乙醇提取物水溶后分别用苯、正丁醇溶剂萃取。生物测定结果显示,苯萃取物对小菜蛾的活性最高,表明其活性成分主要分布在苯萃取物中。苯萃取物通过硅胶柱层析分离,淋洗液为石油醚、石油醚/乙酸乙酯不同比例混合液、乙酸乙酯、乙酸乙酯/甲醇不同比例混合液和甲醇,根据颜色和极性,将收集到的淋洗液分成8个馏份,其中5、6、7号3个馏份对小菜蛾幼虫具有强烈的拒食和毒杀作用,其200倍液对小菜蛾幼虫的拒食率分别为99.8%、99.1%和98.6%,校正死亡率分别为92.1%、91.5%和100%。

Study on Antifeedant and Insecticidal Activities of Extracts and Fractions from Periploca sepium Bunge against Plutella xylostella (L.)

A study on antifeedant and insecticidal activities of extracts and fractions from Periploca sepium Bunge against Plutella xylostella (L.) was carried out by bioassay-driven separation. The bioassay result showed that antifeedant and insecticidal activity of ethanol extract and chloroform extract was higher than that of petroleum ether extract. The result also indicated that insecticidal components were mainly in benzene partition after the ethanol extract was partitioned by benzene and then by n-butyl alcohol. The benzene partition absorbed on silica gel was transferred to top of the silica gel column, then eluted with petroleum ether, mixtures of petroleum ether and ethyl (acetate), ethyl acetate, mixtures of ethyl acetate and methanol and methanol. According to the colors and polarity, 8 fractions were collected, among which fraction 5, 6 and 7 were more active than others. Antifeeding rate and corrected mortality of fraction 5, 6 and 7 were 98.6%~99.8% and 91.5%~100% at the 200 times of (dilution), respectively.