Department of Zoology, Unit of Applied Entomology, University of Madras, Guindy Campus, Chennai, India.
Arch Insect Biochem Physiol. 2023 May;113(1):e21961. doi: 10.1002/arch.21961. Epub 2022 Sep 11.
Mosquitoes are a key threat to millions of people worldwide. They spread the pathogens that cause deadly diseases among humans and animals. Synthetic pesticides are the best agents to control mosquitoes, but they cause several problems for the environment as well as public health. Continuous usage of commonly available insecticides develops multiple resistances among pests. In search of alternatives to synthetic pesticides, botanicals could be one of the best alternatives to control mosquitoes. The present study explores the insecticidal activity of Ocimum americanum against Aedes aegypti larvae and their effect on detoxification enzymes. Leaves of O. americanum were sequentially extracted using hexane, chloroform, and methanol. Among these, hexane extract showed 100% larvicidal activity at 1 g/L concentration for 24 h and the LC value was 0.3 g/L. The phytochemical screening of hexane extract was performed through gas chromatography-mass spectrometry analysis, which showed 27 compounds. The major compounds are squalene (13.03%), camphor (9.77%), and 1-Iodohexadecane (8.02%). The toxicity of active hexane extract was tested against third instar larvae of Chironomus costatus (nontarget organism). Results revealed less toxicity (12.2%) at 1 g/L concentration on the nontarget organism. The enzyme activity of acetylcholinesterase and β-carboxylesterase was significantly inhibited by the hexane extract. The present study reveals the insecticidal potential of O. americanum with minimum effects on nontarget organisms. The O. americanum extract inhibited the activity of A. aegypti's major insecticide-resistant enzymes. O. americanum could be one of the best alternatives to controlling mosquitoes.
蚊子是全球数百万人的主要威胁。它们在人类和动物之间传播病原体，导致致命疾病。合成农药是控制蚊子的最佳药剂，但它们也给环境和公共卫生带来了许多问题。常用杀虫剂的持续使用会导致害虫产生多种抗药性。为了寻找合成农药的替代品，植物性杀虫剂可能是控制蚊子的最佳替代品之一。本研究探讨了美洲薄荷（Ocimum americanum）对埃及伊蚊幼虫的杀虫活性及其对解毒酶的影响。美洲薄荷的叶片依次用己烷、氯仿和甲醇进行提取。其中，己烷提取物在 1 g/L 浓度下对 24 小时的幼虫表现出 100%的杀虫活性，LC 值为 0.3 g/L。通过气相色谱-质谱联用分析对己烷提取物进行了植物化学成分筛查，结果显示有 27 种化合物。主要化合物有角鲨烯（13.03%）、樟脑（9.77%）和 1-碘十六烷（8.02%）。活性己烷提取物对非靶标生物三龄期摇蚊（Chironomus costatus）幼虫的毒性进行了测试。结果表明，在 1 g/L 浓度下，对非靶标生物的毒性较低（12.2%）。己烷提取物显著抑制了乙酰胆碱酯酶和β-羧酸酯酶的活性。本研究揭示了美洲薄荷的杀虫潜力，对非靶标生物的影响最小。该提取物抑制了埃及伊蚊主要抗药性酶的活性。美洲薄荷可能是控制蚊子的最佳替代品之一。
