假蒟提取物对斜纹夜蛾的触杀活性及其有效成分的初步分离

Insecticidal Activity of Extracts fromPiper sarmentosumon Spodoptera litura and Preliminary Purification of Insecticidal Ingredients

为研究假蒟的杀虫生物活性,对假蒟根、茎、叶用石油醚、氯仿、乙酸乙酯、乙醇和甲醇5种溶剂依次进行索氏提取,测定各提取物对斜纹夜蛾幼虫的触杀活性,并对其有效成分进行了初步分离。结果表明,不同部位不同溶剂提取物对斜纹夜蛾幼虫的触杀活性不同,假蒟的主要活性部位为根,其次为茎,叶活性最低;5种有机溶剂提取物中,以石油醚提取物的活性最突出,其他溶剂提取物对试虫基本无生物活性。虫龄越低提取物的杀虫活性越佳,假蒟根石油醚提取物对斜纹夜蛾三至六龄幼虫的致死中浓度(LC50)分别为0.204 9%、0.370 8%、0.853 6%、1.233 1%;假蒟茎石油醚提取物对斜纹夜蛾三至六龄幼虫的LC50分别为0.239 2%、0.397 8%、0.948 5%、1.486 7%。通过对假蒟根石油醚洗提物进行柱层析和TLC分离,得到16个组分,主要活性组分为A、B、C、D,在1mg/mL质量浓度下,其对斜纹夜蛾四龄幼虫24h校正死亡率均达到100%;其次是组分E和组分F,24h校正死亡率分别为53.33%和36.67%;其他组分基本无生物活性。总之,假蒟根石油醚提取物对斜纹夜蛾的触杀活性最高,且虫龄越低杀虫效果越好。

In order to study insecticidal activity of Piper sarmentosum,the bioactivities of the extracts from the roots,stems and leaves of Piper sarmentosumrepectively with petroleum ether,chloroform,ethyl acetate,ethanol,methanol by Sohxlet method were tested using Spodoptera lituralarvae.The results showed that the bioactivities of them were different with different parts of plant samples,the roots of Piper sarmentosum was the maximal,stems secondly,and leaves lastly.Bioactivity of the extract with petroleum ether was the highest,and the others were useless.The results of bioassay test showed that,the contact toxicities of the crude extracts against Spodoptera litura increased with the decrease of ages of the insects.The LC50 of the extracts with petroleum ether from roots and stems of Piper sarmentosum against Spodoptera litura 3th,4th,5th,6th larvae were 0.204 9%,0.370 8%,0.853 6%,1.233 1%and 0.239 2%,0.397 8%,0.948 5%,1.486 7%respectively 24 hafter treatment.Separation of the ingredients extracted in petroleum ether fraction was performed through silica gel column followed by TLC analysis,and 16 ingredient groups were obtained.The bioactivity tests showed that the first（A）,the second（B）,the third（C）and the fourth（D）ingredient groups had the strongest contact toxicities on the 4th larvae of Spodoptera litura,with a mortality of 100% respectively at the dose of 1mg/mL 24 hafter treatment.The fifth（E）and the sixth（F）ingredient groups also had higher contact toxicities,with a mortality of 53.33% and 36.67% respectively,and the others were useless.Petroleum ether extracts from roots of Piper sarmentosum showed the highest activity on Spodoptera lituralarvae,and the earlier the pest stage,the higher the bioactivity.