Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
J Agric Food Chem. 2009 Dec 9;57(23):11234-41. doi: 10.1021/jf901862z.
Derris elliptica Benth. extracts containing rotenone have long been used as natural insecticides, but time-consuming preparation processes and the short shelf life of the extract limit their use in pest control. In this study, stable water-dispersible granules and emulsifiable concentrate liquids containing Derris extract (equivalent to 5% w/w of rotenone) were developed with simple techniques. Accelerated degradation kinetics of rotenone in the Derris extract, and in both formulations, indicated that its degradation followed first-order kinetics. The predicted half-life (t(1/2)) and shelf life (t(90%)) at 30 degrees C of rotenone in Derris extract were 520 and 79 days, respectively. Derris granules and emulsifiable concentrate clearly prolong the stability of rotenone 8-fold (t(90%) = 633 days) and 1.4-fold (t(90%) = 110 days), respectively. The study of rotenone degradation after application onto plants indicated that both formulations would be effective for up to 3 days after spraying. Preliminary efficacy testing indicated that the Derris emulsifiable concentrate was clearly more effective than Derris water-dispersible granules in controlling Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae).
鱼藤酮是从鱼藤属植物中提取的一种天然杀虫剂，长期以来一直被用作天然杀虫剂，但由于提取过程耗时且提取物的保质期短，限制了其在害虫防治中的应用。在本研究中，采用简单的技术开发了含有鱼藤提取物（相当于 5%w/w 的鱼藤酮）的稳定水分散粒剂和可乳化浓缩液。鱼藤提取物及两种制剂中鱼藤酮的加速降解动力学表明，其降解遵循一级动力学。在 30°C 下，鱼藤提取物中鱼藤酮的预测半衰期（t(1/2)）和货架期（t(90%)）分别为 520 和 79 天。鱼藤颗粒和可乳化浓缩液分别将鱼藤酮的稳定性延长了 8 倍（t(90%)=633 天）和 1.4 倍（t(90%)=110 天）。在植物上施用鱼藤酮后的降解研究表明，两种制剂在施药后 3 天内均有效。初步药效试验表明，与鱼藤水分散粒剂相比，鱼藤可乳化浓缩液对斜纹夜蛾（鳞翅目：夜蛾科）的防治效果明显更好。
