Mosquito Repellency Effects of The Essential Oils from Cinnamomum iners Leaves and Barks

Abstract

Synthetic mosquito repellents containing DEET (N, N-diethyl-3-methylbenzamide), DEPA (N, N-diethyl phenylacetamide), permethrin and deltamethrin as active components are known to be the most effective repellents. However, these types of repellents have contributed to numerous toxic effects on not only the environment, but also non-target organisms. The use of natural products such as essential oils is reported as a safe alternative. To date, the study on repellency activities against mosquitoes using Malaysian plants is rare. In the present study, essential oils from leaves and barks of Cinnamomum iners have been reported to show repellency activity, and the whole plant have been used by the local communities to repel mosquitoes and other blood-sucking insects. Repellency assay of the oils against Aedes aegypti was conducted using the percentage repellency bioassay method at three different concentrations: 1%, 5% and 10%. The results showed that the essential oils from barks had a significant percentage repellency (p<0.05) when compared to essential oils from leaves. Two main compounds were identified using the GC-MS: 1-isopropenyl-4-methyl-1,2-cyclohexanediol and 2-octen-1-ol,3,7-dimethyl (geraniol) from the bark and leaf essential oils, respectively. The essential oils demonstrated promising insect repellency activity which has the potential for further development into formulations that may serve as alternatives to DEET or be used as natural bioinsecticides to kill mosquitoes.