Larvicidal activity of 94 extracts from ten plant species of northeastern of Brazil against Aedes aegypti L. (Diptera: Culicidae)

In an effort to find effective and affordable ways to control of Aedes aegypti L. (Diptera: Culicidae), the larvicidal activities of 94 extracts from ten plant species belonging to eight families Guettarda grazielae and Spermacoce verticillata (Rubiaceae), Coccoloba mollis and Triplaris americana (Polygonaceae), Eschweilera ovata (Lecytidaceae), Merremia aegyptia (Convolvulaceae), Ouratea nitida (Ochnnaceae), Protium heptaphyllum (Burseraceae), Rourea doniana (Connaraceae), and Tovomita brevistaminea (Guttiferae)], widely found in the northeast of Brazil, were initially screened at 250 μg/mL. Nineteen of the 94 extracts from six plant species (C. mollis, G. grazielae, M. aegyptia, R. doniana, S. verticillata, and T. americana) showed significant activity (>75% mortality) against the fourth instar larvae. Some of these extracts showed 100% mosquito larvae mortality, with LD₅₀ values lower 200 μg/mL. When compared to synthetic insecticide Temephos (LD₅₀ 8.7 μg/mL), two of them, hexane (LD₅₀ 12.1 μg/mL) and ethyl acetate (LD₅₀ 51.6 μg/mL) extracts from stems of R. doniana and G. grazielae, respectively, were the most effective. The isolation and purification of these extracts are in progress and evaluation of these compounds will be needed to identify the active component.