Solomon_2026_Neotrop.Entomol_55_

The growing resistance of Anopheles gambiae Giles, 1902 to synthetic insecticides poses a major challenge to malaria control, driving interest in botanical alternatives. This study assessed the mosquitocidal and enzyme-inhibitory potential of Citrus sinensis (L.) Osbeck, 1765 essential oil (CiSEO) and its primary constituents through in vivo bioassays and in silico analyses. Larvicidal and adulticidal activities were evaluated following World Health Organization (WHO) protocols, and biochemical assays measured acetylcholinesterase (AChE) and glutathione S-transferase (GST) inhibition, along with superoxide dismutase (SOD) and catalase (CAT) activities. Molecular docking and molecular dynamics (MD) simulations examined interactions with A. gambiae AChE and GST. CiSEO showed strong toxicity against larvae (LC(50)=45.68 microg/mL) and adults (LC(50)=10.06 microg/mL). Limonene and L-carvone were the most potent constituents, with LC(50) values of 17.31 microg/mL and 6.53 microg/mL, respectively. CiSEO and some of its compounds significantly inhibited AChE and GST, while limonene, geraniol, L-carvone, and linalool increased SOD and CAT activities, suggesting induced oxidative stress. Docking identified L-carvone, citral, Naphthalene,1,2,3,5,6,8a hexahydro-4,7-dimethyl-1-methyl ethyl (NHDME), 1-methyl-4-(ethyl-ethylene trans-2-cyclohexen-1-ol (MEET), and 3-carene as strong AChE binders, and NHDME, geraniol, 3-carene, MEET, and limonene as top GST binders. MD simulations revealed MEET formed the most stable AChE complex, supported by low root mean square deviation (RMSD), root mean square fluctuation (RMSF), and radius of gyration values (Rg), and the highest hydrogen-bond (H-Bond) stability. These results demonstrate that CiSEO and its bioactive constituents possess potent mosquitocidal activity and target key detoxification and neural enzymes in A. gambiae. Their efficacy, combined with potential environmental safety, supports further development as eco-friendly alternatives for malaria vector control.