Muthukumaran Udaiyan, Govindarajan Marimuthu, Rajeswary Mohan, Hoti S L
Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar, 608 002, Tamil Nadu, India.
Parasitol Res. 2015 May;114(5):1817-27. doi: 10.1007/s00436-015-4368-4. Epub 2015 Feb 10.
Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the environment by contaminating soil, water, and air, and then natural products may be an alternative to synthetic insecticides because they are effective, biodegradable, eco-friendly, and safe to environment. Botanical origin may serve as suitable alternative biocontrol techniques in the future. The present study was carried out to establish the larvicidal potential of leaf extracts of Gmelina asiatica and synthesized silver nanoparticles using aqueous leaf extract against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of An. stephensi (lethal dose (LC₅₀) = 22.44 μg/mL; LC₉₀ 40.65 μg/mL), Ae. aegypti (LC₅₀ = 25.77 μg/mL; LC₉₀ 45.98 μg/mL), and C. quinquefasciatus (LC₅₀ = 27.83 μg/mL; LC₉₀ 48.92 μg/mL), respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of G. asiatica to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach and the AgNps formed can be potential mosquito larvicidal agents.
蚊子是吸食血液的昆虫，也是传播疟疾、黄热病、登革热和丝虫病等人类疾病的最重要病媒。持续使用合成杀虫剂已导致蚊子产生抗药性。合成杀虫剂有毒，会通过污染土壤、水和空气来影响环境，因此天然产物可能是合成杀虫剂的替代品，因为它们有效、可生物降解、对生态友好且对环境安全。植物源在未来可能成为合适的替代生物防治技术。本研究旨在确定亚洲石梓叶提取物及使用水叶提取物合成的银纳米颗粒对斯氏按蚊、埃及伊蚊和致倦库蚊末龄三龄幼虫的杀幼虫潜力。将幼虫暴露于不同浓度的植物提取物和合成的银纳米颗粒中24小时。通过紫外可见光谱、傅里叶变换红外光谱、扫描电子显微镜、透射电子显微镜和能量色散X射线光谱分析记录结果，这些分析支持了银纳米颗粒的生物合成和表征。在合成的银纳米颗粒对斯氏按蚊幼虫（半数致死剂量（LC₅₀）= 22.44 μg/mL；LC₉₀ 40.65 μg/mL）、埃及伊蚊（LC₅₀ = 25.77 μg/mL；LC₉₀ 45.98 μg/mL）和致倦库蚊（LC₅₀ = 27.83 μg/mL；LC₉₀ 48.92 μg/mL）的实验中分别观察到了最大功效。在对照组中未观察到死亡情况。这是关于植物合成纳米颗粒对蚊子幼虫杀灭活性的首次报道。因此，利用亚洲石梓合成银纳米颗粒是一种快速、生态友好的单步方法，所形成的银纳米颗粒可能是潜在的杀蚊幼虫剂。
