# Chemical composition and larvicidal efficacy of essential oils from three artemisia species endemic to the Mediterranean region against Culex pipiens (L.), insecticide-resistant vector: in vivo and in silico studies

## TL;DR

This study tests essential oils from three Mediterranean Artemisia plants to kill Culex pipiens mosquito larvae, a disease-spreading insect, and finds one species particularly effective.

## Contribution

The study introduces a new natural larvicidal alternative using essential oils from endemic Artemisia species against insecticide-resistant mosquitoes.

## Key findings

- A. negrei essential oil showed the highest larvicidal activity against C. pipiens larvae.
- In silico simulations confirmed strong binding affinities of key compounds in the oils.
- A. herba-alba, despite high oxygenated monoterpenes, had the lowest larvicidal effectiveness.

## Abstract

This study aims to evaluate the larvicidal efficacy of essential oils extracted from three North African endemic Artemisia (A) species against the Culex pipiens mosquito, a major vector of emerging or re-emerging viruses that pose a threat to public and veterinary health in Africa, using both in vivo and in silico approaches.

Third- and fourth-instar larvae were exposed to varying concentrations of essential oils from the selected Artemisia species. Lethal concentrations LC10, LC50, and LC90 for each essential oil were determined through probit analysis. The susceptibility of C. pipiens was also compared to that of the standard insecticide, temephos, under controlled laboratory conditions. Additionally, in silico studies, including molecular docking and dynamics simulations, were conducted on the major chemical constituents to further interpret and explain the in vivo results.

Gas chromatography analyses revealed that the essential oil of A. negrei was dominated by β-thujone (29.02%) and camphor (14.68%). In A. herba-alba Asso, α-thujone (49.19%) was the predominant compound, followed by terpinen-4-ol (9.82%). The essential oil of A. campestris was mainly characterized by camphor (33.07%) and 1,8-cineole (5.26%). A. negrei exhibited the highest larvicidal activity against C. pipiens, followed by A. campestris. In contrast, the essential oil of A. herba-alba Asso, despite its richness in oxygenated monoterpenes, showed the lowest larvicidal effectiveness. In silico investigations revealed that the examined compounds had promising binding affinities within the receptor’s active site, comparable to those of the reference insecticide, temephos.

The results of this study suggest that A. negrei, an endemic species from Morocco, holds significant potential for managing C. pipiens populations and provides a promising alternative to chemical insecticides.