Larvicidal activity of cerbera odollam gaertn against a dengue vector, Aedes aegypti (diptera: Culicidae)

Abstract

Mosquitoes act as vectors of hazardous human diseases and are a major public health problem. Aedes aegypti is a vector of dengue. Chemical treatment is an effective method of controlling mosquitoes but is unsafe for the environment. It is crucial that new, environmentally safe products be developed. Plants can be used as an alternative source of mosquito larval control materials. This study was conducted to evaluate the larvicidal activity of Cerbera odollam against a dengue vector, A. aegypti. The larvicidal activity of crude extracts, fractions, and subfractions of C. odollam was tested against the third-instar larvae of A. aegypti. The larval mortality was determined at 6, 12, 24, and 48 h of exposure. The results showed that the crude extracts of rinds, stem bark, leaves, and seed kernels had poor larvicidal effects. However, the highest larval mortality was shown when the crude extract of seed kernels was used at a concentration of 2.0 g/l after an exposure of 48 h. The larvicidal activity of the fractions derived from the crude extract of seed kernels led to high larval mortality in the ethyl acetate fraction, moderate mortality in the n-hexane fraction, and a very low larvicidal effect in the insoluble fraction. The LC50 values of the ethyl acetate and n-hexane fractions were 0.07 and 0.14 g/l, whereas the LC90 values were 0.42 and 1.0 g/l, respectively. The larvicidal activity of the subfractions yielded the highest larval mortality in subfractions 1 and 7. The bioactive compounds of C. odollam possess potency as larvicidal substances.