Comparative larvicidal efficacies of eucalyptus oil and temephos on Aedes mosquito vectors and in silico interaction of phytocompounds with acetylcholinesterase protein

Abstract Background Aedes aegypti and Aedes albopictus are crucial vectors of dengue, chikungunya and Zika viruses in India and globally. Insecticide resistance in these mosquitoes suggests the exploration of alternative control strategies. The present study assessed the larvicidal efficacy of eucalyptus oil and in silico analysis of 16 phytocompounds to predict molecular docking with acetylcholinesterase (AChE) protein, ADME and toxicity analysis. Temephos was the positive control for bioassay and in silico studies. Results The results showed that the 50% (LC 50 ) and 90% mortalities (LC 90 ) with eucalyptus oil were found at 14.8 mg/l and 50.7 mg/l for Ae. aegypti and 16.9 mg/l and 42.4 mg/l for Ae. albopictus , respectively. Temephos showed 50% (LC 50 ) and 90% mortalities (LC 90 ) at 0.0004 and 0.028 mg/l for Ae. aegypti , and 0.0004 and 0.031 mg/l for Ae. albopictus , respectively. The 3-carene was the most abundant compound in eucalyptus oil. The AChE docking score ranged from − 5.2 (α-thujene) to − 6.5 Kcal/mol (longifolene-V4) in comparison to − 5.2 Kcal/mol of temephos. The AChE showed 3 to 6 amino acid interactions with ligands, along with single (Terpinen-4-ol) and double ( l -α-Terpineol) hydrogen bonds. The toxicity prediction suggests that the majority of phytocompounds are safe for various classes of toxicity, except for blood-brain barrier and ecotoxicity targets and Cytochrome CYP2C9 classes. The (−)-trans-pinene and longifolene (V4) may be the most effective and least hazardous larvicides. Conclusion The findings suggest that eucalyptus oil showed moderate larvicidal efficacy but significantly lower toxicity than temephos. Also, many phytocompounds of eucalyptus oil may be potential candidates in designing new, effective and eco-friendly larvicides for Aedes and other mosquitoes.