Department of Zoology, Annamalai University, Annamalainagar, Tamil Nadu, India.
Indian J Med Res. 2013;138(1):129-34.
BACKGROUND & OBJECTIVES: In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae).
Larvicidal activity of P. dulce plant extracts was studied in the range of 60 to 450 mg/l against early third instar larvae of An. stephensi and Ae. aegypti in the laboratory. The larval mortality was observed after 24 h of exposure. The ovicidal activity was determined against An. stephensi and Ae. aegypti to various concentrations ranging from 100 to 750 mg/l under the laboratory conditions. Mean per cent hatchability of the eggs were observed after 48 h post treatment.
All leaf and seed extracts showed moderate larvicidal and ovicidal effects; however, the highest larval mortality was found in methanol extract of leaf of P. dulce against the larvae of An. stephensi and Ae. aegypti with the LC₅₀ and LC₉₀ values 145.43, 155.78 mg/l and 251.23, 279.73 mg/l, respectively. The per cent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Zero hatchability was observed at 400 mg/l for leaf methanol extract and 625 mg/l for seed methanol extract of P. dulce against An. stephensi and Ae. aegypti, respectively. Compared to leaf extracts, seed extracts have low potency against the two mosquitoes.
INTERPRETATION & CONCLUSIONS: The present results suggest that the leaf and seed extracts of P. dulce have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes.
鉴于最近人们对开发植物源杀虫剂作为化学杀虫剂替代品的兴趣日益浓厚，本研究旨在评估药用植物甜叶菊的粗正己烷、苯、氯仿、乙酸乙酯和甲醇溶剂提取物对蚊虫传播媒介致倦库蚊和埃及伊蚊的杀幼虫和杀卵活性。
在实验室中，用 60 至 450mg/L 的浓度研究了甜叶菊植物提取物对早期三龄幼虫的杀幼虫活性致倦库蚊和埃及伊蚊。暴露 24 小时后观察幼虫死亡率。在实验室条件下，用 100 至 750mg/L 的不同浓度测定对致倦库蚊和埃及伊蚊的杀卵活性。处理后 48 小时观察卵的平均孵化率。
叶和种子提取物均显示出中等的杀幼虫和杀卵作用；然而，甲醇提取物对致倦库蚊和埃及伊蚊幼虫的致死率最高，LC₅₀和 LC₉₀值分别为 145.43 和 155.78mg/L，251.23 和 279.73mg/L。孵化率与提取物浓度成反比，与卵成正比。甲醇提取物对致倦库蚊和埃及伊蚊的叶和种子的零孵化率分别为 400mg/L 和 625mg/L。与叶提取物相比，种子提取物对这两种蚊子的活性较低。
本研究结果表明，甜叶菊的叶和种子提取物具有作为控制蚊子的理想生态友好方法的潜力。
