Larvicidal effect of compounds isolated from Maerua siamensis (Capparidaceae) against Aedes aegypti (Diptera: Culicidae) larvae

Background: Dengue is a major problem for humanity. Most people use insecticides to eliminate larvae of Aedes aegypti, which requires heavy chemicals use that affects the environment and human health. Therefore, in this research, the focus was on the larvicidal efficacy of pure compounds from the leaves and twigs of Maerua siamensis against the larvae of A. aegypti. Results: Larval mortality was observed after a 24-h exposure. The 1H-indole-3 acetonitrile glycosides cappariloside A and cappariloside B and the triterpene lupeol showed strong larvicidal effects (24-h LC₅₀ = 71.14, 99.79 and 133.03 ppm). After 48 h, cappariloside B caused the most potential mortality with an LC₅₀ of 1.56 ppm and lupeol had the highest lethal concentration at LC₅₀ = 158.71 ppm. Additionally, consistency was observed between the toxicity tests and detoxification enzyme activity. Most compounds, except for lupeol and vanillin, reduce the activity of glutathione-s-transferase, whereas no significant differences were between control and treated groups for carboxylesterase. Conclusions: Cappariloside A and cappariloside B are good potential larvicide agents. They showed larvicidal activity against Ae. aegypti larvae with LC₅₀ = 71.14 and 99.79 ppm at 24 and 48 h, respectively.