水黄皮中水黄皮素的提取及其对桔小实蝇的杀虫活性

桔小实蝇是一种毁灭性害虫，可为害200多种水果，目前其防治方法或毒性大，对环境不友好，或成本高昂。本研究拟采用廉价易得的水黄皮荚果为原料，采用超声波辅助提取法，单因素试验比较乙醇浓度，乙酸乙酯、石油醚、正己烷和乙醇的料液比对水黄皮荚果中水黄皮素提取率的影响，得出最优溶剂及其料液比；再分别采用浸渍法和叶碟法测定其提取物对桔小实蝇的卵孵化抑制活性和对1龄幼虫的胃毒活性。结果表明，乙醇最佳提取浓度为60%，乙酸乙酯、石油醚、正己烷与60%乙醇的最佳料液比分别为1∶30、1∶20、1∶30和1∶25，提取率分别为0.48%、0.31%、0.37%和0.44%，即1∶30乙酸乙酯的提取效果最好。杀虫活性研究表明，2%水黄皮提取物对桔小实蝇的卵孵化抑制作用最强，校正孵化抑制率为58.53%，6%提取物对卵孵化抑制作用次之，校正孵化抑制率为46.46%；4%提取物对桔小实蝇1龄幼虫胃毒活性最好，24 h校正死亡率为54.05%，48 h校正死亡率为95.94%。以乙酸乙酯为溶剂，料液比1∶30时，水黄皮中水黄皮素的提取效果最好，其提取率是0.48%。水黄皮提取物对桔小实蝇的卵孵化有抑制作用，对1龄幼虫有胃毒活性，因此有望开发为针对桔小实蝇的植物源杀虫剂。

Extraction of Karanjin from Pongamia pinnata and Its Insecticidal Activity Against Bactrocera dorsalis

Bactrocera dorsalis is a destructive pest, which can harm more than 200 fruits. At present, prevention and control measures of B. dorsalis are toxic, environmentally unfriendly, or costly. In this study, Pongamia pinnata pod, which is cheap and easily available, was as the raw material, and ultrasonic-assisted extraction was performed to extract karanjin from its powder. Effect of ethanol concentration, material ratios of ethyl acetate, petroleum ether, n-hexane and ethanol on extraction rate of karanjin were compared by single factor experiments to obtain the optimal solvent and material/solvent ratio. Egg hatching inhibition activity of EPP against B. dorsalis and its gastric toxicity on 1st instar larvae of B. dorsalis was measured by the immersion method and leaf disc method, respectively. The optimal concentration of ethanol was 60%, and the best material-liquid ratios of ethyl acetate, petroleum ether, n-hexane and 60% ethanol was 1∶30, 1∶20, 1∶30 and 1∶25, respectively, with the extraction rates 0.48%, 0.31%, 0.37% and 0.44%, respectively, suggesting that the optimal solvent is ethyl acetate with material-liquid ratio 1∶30. The results of insecticidal activity showed that 2% EPP had the strongest egg hatching inhibition activity on B. dorsalis with corrected inhibition rate 58.53%, and 6% EPP the second, with corrected hatching inhibition rate was 46.46%; 4% EPP had the best gastric toxicity against 1st instar larvae of B. dorsalis, with 24 hours corrected mortality 54.05%, and 48 hours corrected mortality 95.94%. Extraction rate of karanjin from the pod powder of P. pinnata was the highest when the solvent was ethyl acetate, and solid-liquid ratio was 1∶30, with the extraction rate 0.48%. EPP had an egg hatching inhibition activity against B. dorsalis and gastric toxicity activity on its 1st instar larvae, so it is expected to be developed as a plant-derived pesticide against B. dorsalis.