Larvicidal efficacy and ecotoxicological profile of Coleus aromaticus phytocompounds against Aedes albopictus: In vitro and in silico Assessment

Mosquitoes are major vectors of life threatening diseases, including dengue, chikungunya, yellow fever, Zika, malaria, West Nile fever, and Japanese encephalitis, posing significant global public health challenges. The widespread emergence of resistance to synthetic insecticides, coupled with their adverse environmental impacts, has intensified the need for sustainable and eco-friendly alternatives. In this context, plant derived phytocompounds have gained attention as potential larvicidal agents.

The methanolic leaf extract of Coleus aromaticus demonstrated potential larvicidal activity against different stages of Aedes albopictus. The LC₅₀ values were determined as 81.73 ppm (second instar), 94.77 ppm (third instar), 107.33 ppm (fourth instar), and 136.06 ppm (pupa), indicating stage dependent susceptibility. Molecular docking analysis targeting the Ae. albopictus labrum interacting saliva 2 protein (LIPS-2) (PDB ID: 7TDR) revealed notable binding affinities of phytoconstituents, including rutin (-5.536 kcal/mol), apigenin (-5.413 kcal/mol), carvacrol (-5.203 kcal/mol), and quercetin (-5.131 kcal/mol). Furthermore, in silico ecotoxicological assessment using ProTox-3.0 predicted low toxicity profiles for the evaluated compounds, supporting their environmental safety.

The findings demonstrate that C. aromaticus possesses potent larvicidal activity and its bioactive phytocompounds exhibit significant molecular interactions with target proteins, along with low predicted ecotoxicity. These results highlight its potential as a promising, eco-friendly alternative for the development of sustainable mosquito vector control strategies.