Abstract：
Malaria and dengue are diseases transmitted by mosquitoes of the genera Anopheles and Aedes resistant to commercial insecticides, which are toxic to non-target animals. Alternatively, eco-friendly strategies have focused on searching for essential oil (EO) from plants to control these mosquitoes. In this aspect, this study was carried out to investigate the toxicity of the EO from Tetradenia riparia and its main constituent against Anopheles and Aedes larvae and non-target animals Toxorhynchites haemorrhoidalis and Gambusia affinis. The mechanism of the larvicidal action of the EO and its main compound was investigated by the acetylcholinesterase (AChE) inhibition. The EO from T. riparia was extracted by hydrodistillation with yield of 1.4 ± 0.17%. The analysis of the EO by GC-MS and GC-FID revealed fenchone (38.62%) as the main compound. The EO (100 ppm) showed larvicidal activity against Anopheles and Aedes larvae (91 to 100% of mortality) (LC50 from 29.31 to 40.76 ppm). On the other hand, fenchone (10 ppm) showed more activity (89 to 100% of mortality) (LC50 from 5.93 to 7.00 ppm) than the EO. The EO and fenchone caused the inhibition of AChE (IC50 from 1.93 to 2.65 ppm), suggesting the inhibition of this enzyme as a possible mechanism of larvicidal action. Regarding toxicity, the EO (1000 ppm) and fenchone (100 ppm) showed low toxicity against T. haemorrhoidalis and G. affinis (9 to 74% of mortality) (LC50 from 170.50 to 924.89 ppm) (SI/PSF from 17.99 to 31.91) than the α-cypermethrin (0.52 ppm) which was extremally toxic against these non-target animals (100% of mortality, LC50 from 0.22 to 0.29 ppm). This significant larvicidal activity of the T. riparia EO and its main constituent, along with the low toxicity towards non-target organisms indicate these samples as a possible eco-friendly alternative for the control of malaria and dengue vectors.
摘要：
疟疾和登革热是由对商业杀虫剂有抗性的按蚊和伊蚊属蚊子传播的疾病,对非目标动物有毒。或者，环保策略的重点是从植物中寻找精油（EO）来控制这些蚊子。在这方面,进行这项研究是为了研究利帕氏四虫及其主要成分的EO对按蚊和伊蚊幼虫以及非目标动物的毒性。通过乙酰胆碱酯酶（AChE）抑制研究了EO及其主要化合物的杀幼虫作用机理。通过加氢蒸馏从T.riparia中提取EO，收率为1.4±0.17％。通过GC-MS和GC-FID对EO的分析显示芬酮(38.62%)为主要化合物。EO（100ppm）显示出对按蚊和伊蚊幼虫的杀幼虫活性（死亡率为91％至100％）（LC50为29.31至40.76ppm）。另一方面,fenchone（10ppm）比EO显示出更高的活性（死亡率为89％至100％）（LC50从5.93ppm至7.00ppm）。EO和Fenchone引起AChE的抑制（IC50从1.93到2.65ppm），表明该酶的抑制作用是幼虫作用的可能机制。关于毒性，EO（1000ppm）和Fenchone（100ppm）对痔疮和G.affinis显示低毒性（死亡率的9至74％）（LC50从170.50至924.89ppm）（SI/PSF从17.99至31.91）比α-氯氰菊酯（0.52ppm）对这些非目标动物具有极大的毒性（死亡率的100％，LC50从0.22到0.29ppm)。这种重要的杀幼虫活动的T.ripariaEO及其主要成分，除了对非靶标生物的低毒性外，这些样品还表明它们可能是控制疟疾和登革热媒介的生态友好型替代品。
