In Vivo Efficacy and In Silico Larvicidal Prediction of Essential Oils and Aromatic Extracts from Cinnamomum verum Against Culex pipiens Larvae (Diptera: Culicidae)

Mosquitoes, particularly Culex pipiens, transmit vector-borne diseases that pose significant global health risks. Traditional chemical control methods face challenges such as environmental impact and resistance. This study investigated the in vivo larvicidal activity of essential oils (EOs) and aromatic extracts from Cinnamomum verum against Culex pipiens larvae. It also explored the in silico potential of acetylcholinesterase and chitin synthase 2 as molecular targets for effective control. Hydro-ethanolic and ethanolic extracts, as well as EOs, were prepared from C. verum. Chemical characterization was conducted using gas chromatography-mass spectrometry (GC-MS). Bioassays were carried out to establish the lethal concentrations of the extracts on C. pipiens larvae. Larvicidal efficacy was assessed with mortality rates calculated using Abbott's formula. Acetylcholinesterase and chitin synthase 2 crystal structures were sourced from the Protein Data Bank and used for docking studies. The hydro-ethanolic and ethanolic extracts yielded 10.20% and 9.16%, respectively. Most molecules in C. verum exhibited inhibitory effects ranging from -3.991 to -6.276 kcal/mol at the acetylcholinesterase receptor and -2.935 to -5.665 kcal/mol at the chitin synthase 2 receptor. In silico results identified alpha-humulene, 2-propenal, 3-(4-methoxyphenyl)-, and acetic acid cinnamyl ester as key inhibitors of acetylcholinesterase (g-scores: -6.276 to -6.099 kcal/mol). At the chitin synthase 2 receptor, acetic acid cinnamyl ester and 3-allyl-6-methoxyphenol showed strong inhibition (g-scores: -5.665 to -4.866 kcal/mol), highlighting their eco-friendly insecticidal potential. The findings of this study showed that Cinnamomum verum EOs and extracts demonstrated effective larvicidal properties, with promising in silico results supporting their potential as eco-friendly alternatives to chemical insecticides.