茶树油微囊乳液对水蛭的驱避效果研究

  目的  将茶树油制备成微囊乳液, 评价其对水蛭的驱避效果并阐明驱避机理。  方法  以吐温20作为增溶剂制备茶树油水溶液。司盘80作为乳化剂制备得茶树油乳液，以明胶、海藻酸钠作为囊材，采用复凝聚法制备茶树油微囊，对微囊的粒径、形貌及结合方式等进行表征。将微囊分散到茶树油乳液中即得茶树油微囊乳液。采用滤纸圈法、水中驱避试验考察比较茶树油微囊乳液、茶树油水溶液、空白微囊及阳性药物驱蚊酯对日本医蛭在不同环境中的驱避作用及茶树油微囊乳液的驱避时长。以体内乙酰胆碱酯酶(AchE)、谷胱甘肽S转移酶(GST)和羧酸酯酶(CarE)活性变化为指标，阐明茶树油微囊乳液对水蛭的驱避机理。  结果  优化得到复凝聚产率较高的明胶与海藻酸钠最佳配比处方，成功制备粒径分布不均一、包封率较高的微囊。根据正交设计筛选出最优处方，制备得分散均匀、稳定均一茶树油微囊乳液。药效学实验表明其驱避时间长、驱避效率高。茶树油微囊乳液通过提高水蛭体内AchE活性、抑制GST及CarE活性发挥驱避作用。  结论  茶树油微囊乳液可避免茶树油挥发, 延长驱避水蛭的有效作用时间, 为天然精油作为驱避剂研发提供新思路, 具有广阔的市场前景。 

The Repellent Effect of Tea Tree Oil Microcapsules Emulsion on Leeches

  OBJECTIVE  To prepare tea tree oil into microcapsules emulsion, evaluate its repellent effects on leeches and clarify the repellent mechanisms.  METHODS  Tea tree oil aqueous solution was prepared with Tween 20 as solubilizer. Span 80 was used as the emulsifier to prepare tea oil emulsion. Gelatin and sodium alginate were used by complex coacervation method to prepare tea tree oil microcapsules. The particle size, morphology and the binding mode of microcapsules were characterized. The tea tree oil microcapsules emulsion was obtained by dispersing the microcapsules into the tea tree oil emulsion. The filter-paper ring method and the repellent test in water were used to evaluate the repellent effects and time of the tea tree oil microcapsules emulsion, tea oil aqueous solution, blank microcapsules emulsion and the positive drugs on leeches. The activities of acetylcholinesterase (AchE), glutathione S-transferase (GST) and carboxylesterase (CarE) activities in vivo were measured to clarify the repellent mechanisms of tea tree oil microcapsules emulsion on leeches.  RESULTS  The optimal ratio of gelatin and sodium alginate with high coacervation yield was obtained. The microcapsules with uniform particle size, uneven size and high encapsulation efficiency were successfully prepared. According to the orthogonal design, the optimal formulation was obtained, and the tea tree oil microcapsules emulsion was uniformly dispersed and stable. The microcapsules emulsion could effectively repel leeches and prolong the repelling time. It was clarified that tea tree oil microcapsules emulsion played a repellent role by increasing AchE activity and inhibiting GST and CarE activities in vivo.  CONCLUSION  The prepared tea tree oil microcapsules emulsion can avoid the volatilization of tea tree oil, which can prolong the repelling time. In summary, this study provides a new idea for the development of natural essential oil as the repellents with broad market prospects.