Larvicidal activity of the leaf extracts of Spondias mombin Linn. (Anacardiaceae) from various solvents against malarial, dengue and filarial vector mosquitoes (Diptera: Culicidae).

BACKGROUND & OBJECTIVES Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus are vector mosquitoes of dengue, malaria, and filariasis, respectively. Since no vaccine is available to treat these diseases, the control of the main mosquito vectors is essential. As conventional insecticides have limited success, plants may be alternative larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of methanol crude extract, hexane, dichloromethane, acetone, ethyl acetate and methanol fractions of Spondias mombin leaf against IV instar larvae of dengue, malaria, and lymphatic filariasis vector mosquitoes. METHODS A total of 25, IV instar larvae of each target mosquito species were exposed to various concentrations (125-1000 ppm) and were assayed in the laboratory by using the protocol of WHO 2005; the LC50 values were determined by Probit analysis. RESULTS Hexane, dichloromethane and acetone fractions were the most effective against Ae. aegypti with LC50 values of 22.54, 42.13, 45.18 ppm, respectively. Hexane fraction registered the highest activity with LC50 of 92.20 ppm against An. gambiae. It was still hexane fraction that showed better toxicity with LC50 of 326.53 ppm against Cx. quinquefasciatus. CONCLUSION The Spondias mombin leaf extracts proved to be a strong candidate for a natural, safe and stable mosquito larvicide to be used in population control of Ae. aegypti, An. gambiae and Cx. quinquefasciatus and so may replace the conventional Diclorvos to control malaria, dengue and filariasis in Nigeria.