垂序商陆叶片总皂苷的提取及杀虫活性研究

摘要

对纤维素酶-微波协同提取垂序商陆(Phytolacca americana Linn.)叶片总皂苷过程中纤维素酶用量、纤维素酶作用时间、微波提取时间和微波功率进行单因子实验和L9(34)正交实验,测定了4月至10月叶片总皂苷含量及总皂苷提取物对小菜蛾〔Plutella xylostella(Linn.)〕的灭杀活性.结果表明:纤维素酶用量、纤维素酶作用时间、微波提取时间和微波功率均对垂序商陆叶片总皂苷得率有明显影响.垂序商陆叶片总皂苷的最佳提取条件为纤维素酶用量0.08 g·g-1、纤维素酶作用时间100 min、微波提取时间35 s和微波功率400 W;该条件下叶片总皂苷得率为2.53%.随着时间的推移,垂序商陆叶片总皂苷含量呈"升高—稳定—降低"的趋势,总皂苷含量在8月最高, 9月之后急剧下降.在同一处理时间,小菜蛾的校正死亡率随着总皂苷提取物质量浓度的提高逐渐升高;同一质量浓度总皂苷提取物条件下,小菜蛾的校正死亡率随着处理时间的延长也逐渐升高.质量浓度5.0 mg·mL-1总皂苷提取物处理96 h时小菜蛾的校正死亡率达73.3%.9月总皂苷提取物对小菜蛾的灭杀效果优于5月和7月.本研究初步建立垂序商陆叶片总皂苷的纤维素酶-微波协同提取条件,明确其叶片总皂苷提取物对小菜蛾具有一定的灭杀活性,为利用垂序商陆叶片开发生物农药提供参考.%Single factor experiment and L9(34)orthogonal test were conducted on cellulase dosage, cellulase action time, microwave extraction time, and microwave power during the cellulase?microwave assisted extraction process of total saponins from Phytolacca americana Linn. leaves, and total saponins content in leaves collected from April to October and insecticidal activity of total saponins extract against Plutella xylostella(Linn.)were determined. The results show that cellulase dosage, cellulase action time,microwave extraction time,and microwave power have obvious influences on yield of total saponins from P. americana leaves. The optimum extraction condition of total saponins from P. americana leaves is 0.08 g·g-1of cellulase dosage,100 min of cellulase action time,35 s of microwave extraction time,and 400 W of microwave power; yield of total saponins from leaves is 2.53% under such condition. With prolonging of time, total saponins content in P. americana leaves shows a tendency of"increasing-stable-decreasing",which is the highest in August,and sharply decreases after September. At the same treating time,adjusted mortality of P. xylostella gradually increases with enhancing of mass concentration of total saponins extract;at the same mass concentration of total saponins extract,adjusted mortality of P.xylostella also gradually increases with prolonging of treating time. The adjusted mortality of P. xylostella reaches 73.3% when treated with mass concentration of 5.0 mg·mL-1of total saponins extract for 96 h. The insecticidal effect of total saponins extract in September is better than that in May and July. This study establishes the cellulase?microwave assisted extraction condition of total saponins from P. americana leaves preliminarily,and it is clear that total saponins extract from its leaves has a certain insecticidal activity against P. xylostella, so this study provides references for the development of biopesticide by using P. americana leaves.