蚊媒疾病,比如疟疾,登革热,和Zika,在全球范围内构成重大公共卫生挑战,影响数百万人。蚊子种群对合成杀虫剂的抵抗力不断增强,这突显了对有效和环保的杀幼虫的迫切需要。虽然化学农药最初是有效的,它们通常会对非目标物种造成负面的环境后果和健康危害,包括人类。本研究旨在评估Trachyspermumammi精油和飞燕草提取物对三种主要蚊子的幼虫的杀幼虫作用:埃及伊蚊,Stephensi按蚊,和库蚊。Ae的蚊虫幼虫。埃及伊蚊,A.Stephensi,Cx.quinquefasciatus在受控的实验室条件下饲养。通过标准生物测定法评估了T.ammi精油和D.speciosum提取物的杀幼虫活性,使用各种浓度的精油(10、20、40、80和160ppm)和提取物(160、320、640、1280和2560ppm)来确定暴露24小时后的致死浓度(LC50)值。收集新鲜的植物材料,通过加氢蒸馏提取的精油,提取物采用甲醇溶剂萃取法制备。使用气相色谱-质谱(GC-MS)检查了T.ammi精油的化学成分。此外,使用薄层色谱(TLC)和核磁共振波谱(NMR)技术对D.speciosum提取物中的化合物进行了初步分析。结果表明,与D.speciosum提取物相比,T.ammi的精油显示出更有效的杀幼虫活性。具体来说,精油对Cx的LC50值为18ppm。Quinquefasciatus和19ppm的Ae。埃及伊蚊.相比之下,D.speciosum提取物对An显示出最强的杀幼虫作用。Stephensi,LC50为517ppm。40ppm的精油和1280ppm的提取物的浓度导致在所有三个物种中100%的死亡率。T.ammi和D.speciosum提取物的精油都表现出浓度依赖性的杀幼虫活性,与未治疗组相比,这些结果具有统计学意义(p<0.001)。GC-MS分析显示百里酚(88.95%),o-cymen-5-ol(4.11%),和γ-松油烯(2.10%)为T.ammi精油的主要成分。此外,TLC证实氯仿和甲醇提取物中均存在生物碱。质子NMR鉴定了这些生物碱的二萜结构。这些发现表明T.ammi精油是天然蚊子控制策略的有希望的候选者。鉴于其功效,有必要进一步研究以探索其在综合病媒管理计划中的潜力。
Mosquito-borne diseases, such as malaria, dengue, and Zika, pose major public health challenges globally, affecting millions of people. The growing resistance of mosquito populations to synthetic insecticides underscores the critical need for effective and environmentally friendly larvicides. Although chemical pesticides can initially be effective, they often lead to negative environmental consequences and health hazards for non-target species, including humans. This study aimed to evaluate the larvicidal effects of Trachyspermum ammi essential oil and Delphinium speciosum extract on the larvae of three major mosquito species: Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Mosquito larvae of Ae. aegypti, An. stephensi, and Cx. quinquefasciatus were reared under controlled laboratory conditions. The larvicidal activity of T. ammi essential oil and D. speciosum extract was evaluated through standard bioassays, using various concentrations of essential oils (10, 20, 40, 80, and 160 ppm) and extracts (160, 320, 640, 1280, and 2560 ppm) to determine the lethal concentration (LC50) values after 24 h of exposure. Fresh plant materials were collected, with the essential oil extracted via hydro-distillation, and the extract prepared using methanol solvent extraction. The chemical composition of T. ammi essential oil was examined using gas chromatography-mass spectrometry (GC-MS). Additionally, the preliminary analysis of the chemical compounds in D. speciosum extract was carried out using thin layer chromatography (TLC) and nuclear magnetic resonance spectroscopy (NMR) techniques. The results indicated that the essential oil of T. ammi exhibited more effective larvicidal activity compared to the D. speciosum extract. Specifically, the essential oil demonstrated LC50 values of 18 ppm for Cx. quinquefasciatus and 19 ppm for Ae. aegypti. In contrast, the D. speciosum extract showed the strongest larvicidal effect against An. stephensi, with an LC50 of 517 ppm. Concentrations of 40 ppm of the essential oil and 1280 ppm of the extract resulted in 100% mortality across all three species. Both the essential oil of T. ammi and the D. speciosum extract exhibited concentration-dependent larvicidal activity, and these results were statistically significant (p < 0.001) compared to the no-treatment group. GC-MS analysis revealed thymol (88.95%), o-cymen-5-ol (4.11%), and γ-terpinene (2.10%) as the major constituents of the T. ammi essential oil. Additionally, TLC verified the presence of alkaloids in both chloroform and methanolic extracts. Proton NMR identified a diterpene structure for these alkaloids. These findings suggest that T. ammi essential oil is a promising candidate for natural mosquito control strategies. Given its efficacy, further research is warranted to explore its potential in integrated vector management programs.