Larvicidal Activity of Extracts from the L. Plant and Sponge Against the Mosquito (Diptera: Culicidae) and Toxicological Assessment on Zebrafish Embryos as Non-Target Organism.

There is a growing need for eco-friendly methods to control disease-carrying insects. The present study aimed to investigate the larvicidal activity of methanolic extracts and their various fractions from a plant, L., and a marine sponge, , against the mosquito, L. Crude methanolic extracts of and were prepared by maceration and successive fractionation were obtained using the liquid-liquid partition of crude extracts. The larvicidal activity of the extracts and their fractions was determined according to the WHO standard method. The results revealed that the -hexane fraction of exhibited the highest larvicidal activity (LC 346.74 μg/mL), exceeding the efficacy of the crude extract and other fractions. Furthermore, the sponge's -hexane (LC 68.39 μg/mL), chloroform (LC 63.03 μg/mL), and -butanol (LC 71.23 μg/mL) fractions showed a significant 3.9 to 4.5 times increase in the larvicidal potency compared to its crude extract (LC = 280.74 μg/mL). The safety of the sponge extracts was tested in the embryos of zebrafish as a non-target organism. In this regard, the crude methanolic extract and -butanol fraction exhibited weak toxicity and chloroform fraction showed no detectable toxicity. This study suggests the sponge as a source for developing safe natural substitutes for use in the battle against mosquito, which may help in reducing the spread of mosquito vectors and mosquito-borne diseases.