Department of Biochemistry, K.S. Rangasamy College of Arts and Science (Autonomous), Tiruchengode, Namakkal, Tamil Nadu, 637215, India.
Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tirunelveli, Tamil Nadu, 627412, India.
Environ Sci Pollut Res Int. 2020 May;27(13):15174-15187. doi: 10.1007/s11356-020-08055-1. Epub 2020 Feb 18.
Mosquitoes are principal vector of several vector-borne diseases affecting human beings leading to thousands of deaths per year and responsible for transmitting diseases like malaria, dengue, chikungunya, yellow fever, Zika virus, Japanese encephalitis, and lymphatic filariasis. In the present study, we evaluated the different solvent extracts of mangrove Avicennia marina for their toxicity against larvae of three major mosquito vectors, as well as selected microbial pathogens. The larvicidal mortality of third instars was observed after 24 h. Highest larval mortality was found for the acetone extract of A. marina against Culex quinquefasciatus (LC = 0.197 mg/ml; LC = 1.5011 mg/ml), Anopheles stephensi (LC = 0.176 mg/ml; LC = 3.6290 mg/ml), and Aedes aegypti (LC = 0.164 mg/ml; LC = 4.3554 mg/ml). GC-MS analysis of acetone extract revealed 5 peaks, i.e., 1-hexyl-2-nitrocyclohexane (3.229%), eicosanoic acid (40.582%), cis-9-hexadecenal (70.54%), oleic acid (4.646%), and di-N-decylsulfone (5.136%). Parallel to larvicidal assay, sub-lethal dosage acetone extracts severely affected the enzyme regulations (α,β-carboxylesterase, GST and CYP450) of third instars. Larval and pupal durations increased in all treatment sub-lethal dosage (0.127, 0.151, 0.177, and 0.197 mg/ml), whereas egg hatchability and means of fecundity decreased compared to control. The survival rate was reduced statistically in Cx. quinquefasciatus (χ = 23.77, df = 1, P = 0.001) in all the treatment dosages as compared to the control. Antimicrobial activity assays showed significant growth inhibition post treatment with acetone and methanol extracts against Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus pneumoniae, Escherichia coli, and Shigella flexneri. Overall, these results indicated the potential employment of A. marina extracts as a source of natural mosquitocidal and antimicrobial compounds of green-based environment.
蚊子是几种媒介传播疾病的主要媒介，这些疾病每年导致数千人死亡，并负责传播疟疾、登革热、基孔肯雅热、黄热病、寨卡病毒、日本脑炎和淋巴丝虫病等疾病。在本研究中，我们评估了红树林植物桐花树的不同溶剂提取物对三种主要蚊子幼虫的毒性，以及对选定的微生物病原体的毒性。在 24 小时后观察到第三龄幼虫的致死率。桐花树丙酮提取物对库蚊（LC = 0.197 mg/ml；LC = 1.5011 mg/ml）、致倦库蚊（LC = 0.176 mg/ml；LC = 3.6290 mg/ml）和埃及伊蚊（LC = 0.164 mg/ml；LC = 4.3554 mg/ml）的幼虫死亡率最高。丙酮提取物的 GC-MS 分析显示了 5 个峰，即 1-己基-2-硝基环己烷（3.229%）、二十烷酸（40.582%）、顺-9-十六烯醛（70.54%）、油酸（4.646%）和二-N-癸基砜（5.136%）。与幼虫致死率测定平行，亚致死剂量的丙酮提取物严重影响了第三龄幼虫的酶调节（α、β-羧酸酯酶、GST 和 CYP450）。所有处理亚致死剂量（0.127、0.151、0.177 和 0.197 mg/ml）均延长了幼虫和蛹期，而与对照相比，卵孵化率和平均产卵量均降低。与对照相比，在所有处理剂量下，库蚊的存活率均显著降低（χ = 23.77，df = 1，P = 0.001）。丙酮和甲醇提取物对鼠伤寒沙门氏菌、肺炎克雷伯菌、铜绿假单胞菌、肺炎链球菌、大肠杆菌和福氏志贺菌的抗菌活性试验显示出显著的生长抑制作用。总的来说，这些结果表明，桐花树提取物有潜力作为天然杀蚊和抗菌化合物的来源，应用于绿色环保领域。
