Evaluation of the Leaf Essential Oil from Artemisia vulgaris and Its Larvicidal and Repellent Activity against Dengue Fever Vector Aedes aegypti-An Experimental and Molecular Docking Investigation.

Aedes aegypti is a mosquito vector that spreads dengue fever and yellow fever worldwide in tropical and subtropical countries. Essential oil isolated from Artemisia vulgaris is found to have larvicidal and repellent action against this vector. The dried leaves were subjected to hydrodistillation using a clevenger-type apparatus for 4 h. The isolated essential oil was analyzed by using gas chromatography-mass spectrometry, and the major insecticidal compounds were identified as α-humulene (0.72%), β-caryophyllene (0.81%), and caryophyllene oxide (15.87%). Larvicidal activity results revealed that the essential oil exposure for 24 h period against the third stage larvae was LC₅₀ = 6.87, LC₉₀ = 59.197 ppm and for the fourth stage larvae LC₅₀ = 4.269, LC₉₀ = 50.363 ppm. Highest mortality rates were observed at 24 h exposure period of third and fourth stages, and the exposed A. aegypti larvae were subjected to histo chemical studies, and the studies revealed that larvae cells got totally damaged (midgut and cortex). The repellent activity results revealed that at 50% concentration of the essential oil showed the highest repellent activity at 60 min protection time against the A. aegypti female mosquitoes. To gain further insights into the insecticidal activity, density functional theory and molecular docking calculations were performed with the active components of this essential oil as the ligand and NS3 protease domain (PDB ID: 2FOM) as a receptor. Molecular docking calculation results show that (E)-β-caryophyllene strongly binds with NS3 protease domain than (Z)-β-caryophyllene, α-humulene, and β-caryophyllene oxide and is the major active component for the insecticidal action. It primarily interacts with the receptor through hydrophobic and ionic forces and using water bridges between the amino acid residues in the binding pocket and (E)-β-caryophyllene.