Selected Essential Oils as Repellents Against Aedes Aegypti: Validation of the Bioconstituents Using Gas Chromatography

Abstract

Plant essential oils have been widely used as fragrance in perfumes or flavouring agents in food products due to their unique characteristic scent of the active constituents. The objective of this study is to qualitatively and quantitatively analyse the repellent activity, and the properties of the bioactive constituents in nutmeg, peppermint, and basil oils. The repellent activity of these essential oils was tested against Aedes aegypti and analysed using gas chromatography-flame ionisation (GC-FID) method. α-pinene, terpinen-4-ol and safrole in nutmeg oil, α-pinene, β-pinene, and menthol in peppermint oil, and methyl chavicol, geraniol, and methyl eugenol in basil oil, were selected for further analysis. Selected constituents were tested for accuracy, intra-and interday precision, recovery, limit of detection (LOD), and limit of quantification (LOQ). Nutmeg oil contributed to the highest percentage of repellence with 70.2%, with the accuracy values ranged from 99.25 - 99.71%. The precision for intra- and interday measurements for all tested constituents ranged between 1.083 - 7.296% and 1.308 - 7.924% respectively. The range of recovery was 97.43 - 100.86%. LOD ranged from 0.005 - 0.4 mol/L, and LOQ (with signal to noise ratio of 10:1) ranged from 0.0002 - 0.025 mol/L. In conclusion, the proposed method is simple, precise, and accurate, for qualitative and quantitative analysis of constituents present in essential oils. Nutmeg oil is an alternative natural mosquito repellent with α-pinene as the main active constituent.