扁蓄对小菜蛾杀虫活性物质初选

Preliminary Screening of the Insecticidal Active Substances in Polygonum aviculare L.to Plutella xylostella

[目的]分离扁蓄中的杀虫活性物质。[方法]采用液-液分配萃取法分离扁蓄乙醇粗提物的活性物质,以小菜蛾为试虫,进行室内毒力测定和杀虫活性跟踪测试,计算萃取率、死亡率和校正死亡率。[结果]扁蓄粗提物对小菜蛾3龄幼虫的LC50为0.0118g/ml。扁蓄乙醇浸膏的石油醚萃取部位的活性最强,得率最高,为21.80%,各溶剂萃取率大小依次为石油醚>正丁醇>乙酸乙酯>氯仿。各萃取物的活性为石油醚>氯仿>正丁醇>乙酸乙酯>水。石油醚萃取物72h对小菜蛾的3龄幼虫触杀活性最高,死亡率和校正死亡率分别为96.7%、96.6%。[结论]扁蓄对小菜蛾具有很高的触杀活性。扁蓄的杀虫活性物质为一类小极性的化合物,在粗提物中得率最高。

[Objective] The research aimed to separate the insecticidal active substances from Polygonum aviculare L.[Method] The active substances in crude extracts from Polygonum aviculare L.were separated with alcohol by liquid-liquid distribution extraction method.With Plutella xylostella as the tested insects,indoor toxicity determination and the tracking test on the insecticidal activity were made to calculate the extraction rate,the mortality rate and the corrected mortality rate.[Result]LC50 of crude extracts from P.aviculare to the 3rd instar larva was 0.011 8 g/ml.The parts extracted by petroleum ether in ethanol-extracts from P.aviculare had the strongest activity and the highest yield（21.80%）.The extraction rates of each solvent was in order as follows：petroleum ether 〉butanol〉ethyl acetate〉chloroform.The activities of each extract was petroleum ether 〉chloroform〉butanol〉ethyl acetate〉water.The extracts by petroleum ether for 72 h had the highest contact toxicity to the 3rd instar larva,with the mortality rate and the corrected mortality rate of 96.7% and 96.6% resp.[Conclusion] P.aviculare had very high contact toxicity to P.xylostella.The insecticidal active substances in P.aviculare were a kind of small-polar compounds with the highest yield in the crude extracts.