Larvicidal Activity of Terminalia Microcarpa Decne Leaf Ethanolic Extract on Aedes Aegypti (L.)

Abstract

The use of synthetic larvicides as a means of controlling the mosquito population can cause detrimental effects to the environment and non-target organisms. Plant-based larvicidal alternatives are therefore being developed as they are safer to the environment and the public. This study aims to assess whether the ethanolic extract of Terminalia microcarpa Decne leaves will be able to cause the mortality of Aedes aegypti larvae and to determine the phytochemicals present in T. microcarpa Decne leaves. Collected leaf samples were air dried and extracted with ethanol. A qualitative analysis was performed in order to identify the secondary metabolites present. A modified larvicidal bioassay was used to evaluate the larvicidal activity of the extract at 5% v/v, 2% v/v, and 1% v/v concentrations.The positive and negative control used were Piper nigrum and distilled water, respectively. The results of the qualitative analysis showed presence of glycosides, flavonoids, saponins, phytosterols, and tannins in T. microcarpa leaves. Complete larval mortality was exhibited at 5% v/v concentration on the 24th and 48th hours. Larval mortality at 2% v/v concentration on the 24th and 48th post-exposure is 96.67% and 100%, respectively. At 1% v/v concentration, the larval mortality on the 24th and 48th hour postexposure is 46.67% and 86.67%, respectively. The lethal concentrations LC50 and LC90 on the 24th hour post-exposure was found to be at 1.03% v/v concentration and 1.59% v/v concentration, respectively. The crude ethanolic extract of T. microcarpa Decne leaves may be a potential larvicide for A. aegypti mosquito larvae.