Abstract Mosquitoes act as vectors to induce various dreadful diseases which continue to cause fatal effect on human beings. Aedes aegypti (Ae. aegypti) is one among the vectors which causes yellow fever, dengue and chikungunya, and Culex quinquefasciatus (C. quinquefasciatus) is another which can cause lymphatic filariasis, a widely distributed tropical disease across the world. In line with the larvicidal activity of sea grasses against the disease vectors, the present contribution has been focused. Two seagrasses namely Enhalus acoroides (L.f) Royle (E. acoroides) and H. ovalis (R.Br) Hook.f. (H. ovalis) collected from the Mandapam Coast, Rameswaram, Tamil Nadu located in South India were washed, shade dried, blended and made in to a fine powder. Sea grass extracts of different concentrations from 62.5 ppm to 500 ppm were prepared in the ratio 1:3 (w/v) using hexane, dichloromethane and ethanol as solvents. The results showed that the hexane extract (500 ppm) of E. acoroides exhibited the larvicidal activity of 62% against the Ae. aegypti after 24 h whereas its ethanol extracts (500 ppm) showed 50% of larvicial activity against C. quinquefasciatus. It could be inferred that the H. ovalis displayed a lesser larvicidal potentiality against Ae. aegypti than that of E. acoroides. The FT Infra-Red characterization of E. acoroides was carried out for the identification of various functional groups. The presence of about 11 organic compounds in E. acoroides was analysed using GC – MS. The significant role of solvents’ polarity in enabling the bioactive compounds to combat against two different mosquito vectors has been discussed. Statistical data such as LC50 (concentration of compound that kills 50% of larva), LC90 (concentration of compound that kills 90% of larva), correlation coefficient (r), χ2 and p values are calculated and discussed.

中文翻译：

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Enhalus acoroides (Lf) royle 和 Halophila orangeis (R. br) hook 的杀蚊幼虫活性。F。对抗致命媒介埃及伊蚊和库蚊

摘要 蚊子作为媒介诱发各种可怕的疾病，这些疾病继续对人类造成致命的影响。埃及伊蚊 (Ae. aegypti) 是引起黄热病、登革热和基孔肯雅热的媒介之一，而库蚊 (C. quinquefasciatus) 是另一种可引起淋巴丝虫病的媒介，这是一种在世界范围内广泛分布的热带疾病。根据海草对病媒的杀幼虫活性，目前的贡献已集中。两种海草，即 Enhalus acoroides (Lf) Royle (E. acoroides) 和 H.椭圆形 (R.Br) Hook.f。从位于印度南部泰米尔纳德邦拉梅斯瓦拉姆的曼达帕姆海岸收集的 (H.椭圆形) 被洗涤、阴干、混合并制成细粉。不同浓度的海草提取物来自 62。使用己烷、二氯甲烷和乙醇作为溶剂以 1:3 (w/v) 的比例制备 5 ppm 至 500 ppm。结果表明，E. acoroides 的己烷提取物 (500 ppm) 对 Ae 表现出 62% 的杀幼虫活性。aegypti 24 小时后，而其乙醇提取物 (500 ppm) 对 C. quinquefasciatus 显示 50% 的幼虫活性。可以推断，卵形嗜血杆菌对 Ae 表现出较小的杀幼虫潜力。aegypti 而不是 E. acoroides。E. acoroides 的 FT 红外表征用于鉴定各种官能团。使用 GC-MS 分析了 E. acoroides 中约 11 种有机化合物的存在。已经讨论了溶剂极性在使生物活性化合物能够对抗两种不同蚊媒方面的重要作用。