Toxicity of<i>Ocimum sanctum</i>L. Essential oil to<i>Aedes aegypti</i>Larvae and its Chemical Composition

Abstract

Abstract The herb essential oil of Ocimum sanctum from Nigeria was investigated for mosquito larvicidal activity and its composition studied by gas chromatography and gas chromato-graphy-mass spectrometry for the first time. A good larvicidal action (LD50 85.11 ppm) against fourth instar Aedes aegypti mosquitoes which was far less than that of a positive control, endosulphan (LC50, 0.96 ppm) was observed for the oil. Seventeen components representing 88.4 % of total oil were fully identified. Oxygenated monoterpenes (51.1 %) and sesquiterpene hydrocarbons (27.5 %) formed the main chemical groups in the oil. The major constituents of the oil were methyleugenol (44.7 %) and isocaryophyllene (16.8 %), which categorise the oil into a different chemical variety. Key Word Index: Ocimum sanctumessential oilmethyleugenolisocaryophylleneAedes aegyptilarval toxicity