Mosquitocidal Potential of Citrus paradisi Seed Essential Oil and Molecular Docking of its Bioactive Constituents against Culex quinquefasciatus Acetylcholinesterase

Mosquito control is an important strategy for preventing mosquito-borne diseases, which contribute significantly to human mortality, morbidity and damage to global socio-economic status. Use of synthetic insecticides as vector control agents leads to environmental hazards through persistence and accumulation of non-biodegradable toxic chemicals. In this study, the adulticidal and larvicidal potentials of Citrus paradisi seed essential oil (CPSEO) on Cx. quinquefasciatus and also the acetylcholinesterase (AChE)-inhibitory potentials of its bioactive compounds using molecular docking were evaluated. Larvae and adult of Cx quinquefasciatus were exposed to 1500, 3000 and 4500 ppm of CPSEO and percentage mortality was determined. CPSEO exhibited larvicidal and adulticidal activity against Cx. quinquefasciatus with percentage mortality increasing with increase in concentration of CPSEO and exposure duration. The LC
50
values of CPSEO against larvae of Cx. quinquefasciatus at 0, 15, 30, 45 and 60 min were 2899.15, 3022.56, 2945.37, 1373.11 and 2047.40 ppm respectively while LC
50
values of CPSEO against adult of Cx. quinquefasciatus at 0, 15, 30, 45 and 60 min were 4660.58, 1567.16, 2700.69, 2513.33 and 2047.40 ppm respectively. Molecular docking analysis showed that out of the 7 compounds (as retrieved from ethnobotanical databases) present in CPSEO that were docked against Cx. quinquefasciatus acetylcholinesterase1 (cqAChE1), naringin and deacetylnomilinic acid glucoside are inhibitors of cqAChE1, with naringin exhibiting a higher binding affinity than the reference inhibitor (1S)-2,2-difluoro-1-[1-(pentan-3-yl)-1H-pyrazol-4-yl]ethan-1-ol). In conclusion, CPSEO exhibited larvicidal and adulticidal activity against Cx quinquefasciatus via inhibition of acetylcholinesterase1 by CPSEO constituents, deacetylnomilinic acid glucoside and especially naringin.