Larvicidal Activity of Lamiaceae and Lauraceae Essential Oils and Their Effects on Enzyme Activities of Culex pipiens L. (Diptera: Culicidae)

The present study was undertaken in order to determine the chemical composition of the leaf Essential Oils (EOs) of five plants (Ocimum basilicum, Lavandula dentata, Mentha piperita, Mentha pulegium, and Laurus nobilis) cultivated in Tebessa (Algeria) and to assess their potential larvicidal activity against the most abundant and investigated mosquito species, Culex pipiens L., 1758 (Diptera, Culicidae). The Essential Oils (EOs) were tested at different concentrations on newly molted 4th instar larvae. The effects of the activities of Acetylcholinesterase (AChE) and Glutathione-S-Transferases (GSTs) on mortality were examined. Their chemical compositions were investigated by GC/MS. The major components of M. pulegium, L. dentata, M. piperita, O. basilicum, and L. nobilis were Pulegone (72.50%), α-Terpinolene (51.13%), Carvone (30.27%), Linalyl acetate (53.89%), and Eucalyptol (47.35%), respectively. The larval mortality was observed after 24 h of exposure. Dose-response relationship was determined for all tested plants EOs. L. nobilis EO was the most effective against C. pipiens, comparatively to the other tested oils. The enzymatic measurements performed in LC₅₀ treated larvae revealed a neurotoxic activity and a stimulation of the detoxification system with evidenced by the inhibition of AChE and an increase in GST activity, respectively. The EOs from tested plants could be an alternative measure for the control of C. pipiens as they contain an efficient source of bioactive compounds, which are generally free from health hazards and environmental pollution.