Larvicidal activity, biochemical effect, histopathological alteration, and biomarker responses induced by <i>Laurus nobilis</i> essential oil in <i>Culex pipiens</i> (Diptera: Culicidae)

Abstract Our current study is devoted to the determination of the chemical profile of the Laurus nobilis essential oil (LNEO), and its larvicidal activity against the most prevalent mosquito ( Culex pipiens ) in the Tebessa area (northeast Algeria). The effects were examined on neurotoxicity, detoxification, and oxidative stress biomarkers, the biochemical, and the morphometric parameters of the larvae. The EO yield of L. nobilis leaves was determined to be 0.96%. According to gas chromatography–mass spectrometry analyses (GC–MS), fifty‐six constituents were found in the L. nobilis EO. eucalyptol (25.62%) was the major chemical component, followed by linalool (11.83%) and α ‐terpinyl acetate (10.18%). This EO exhibited larvicidal activity in bioassay tests conducted in accordance with the World Health Organization standard procedure. The biomarkers' activity revealed a decrease in acetylcholinesterase (AChE) activity and glutathione (GSH) rate. Furthermore, an increase in glutathione S‐transferase (GST), glutathione peroxidase (GPx) activity, and malondialdehyde (MDA) rate was observed after treatment. The morphometric evaluation revealed that the tested EO reduced both the larvae's body volume and weight. Additionally, data showed that treatment altered the nutrition reserves. Finally, treated larvae showed histological changes that were significantly correlated with EO concentration. Conclusively, L. nobilis EO has the potential to be used as an alternative to neurotoxic insecticides to control mosquito infestations.