Phytochemical Profiling and Bioactivity of Essential Oils Extracted From Mosquito-Repellent Plants

This research investigates the extraction and characterization of essential oils from lemongrass (Cymbopogon citratus) and scent leaf (Ocimum gratissium) , two plants known for their mosquito repellent properties. The essential oils were obtained using hydro-distillation and analyzed for their physico-chemical properties and chemical composition using ASTM standard methods and Gas Chromatography-Mass Spectrometry (GC-MS). Results showed that lemongrass oil had a higher specific gravity (1.027) and was dominated by fatty acid esters (64%) and diterpenes (21%), suggesting a slow-release profile suitable for long lasting repellency. In contrast, scent leaf oil exhibited higher volatile content (9.55%) and a chemically diverse profile, including monoterpenes (19.13%), sesquiterpenes (15.17%), and various fatty acids (33.57%), indicating strong immediate repellency. The chemical difference between both oils is linked to plant type, environment, and extraction conditions. Their combined use offers a synergistic solution for developing effective, natural mosquito repellents that provide both rapid and sustained action. This study highlights the relevance of essential oil profiling in formulating plant-based alternatives to synthetic repellents and calls for further toxicological and field efficacy studies to support commercial application.