Molecular docking and bio-control efficacy of Mesosphaerum suaveolens (L.) Kuntze against mosquito Culex quinquefasciatus Say

Abstract

Plant-based insecticides are gaining attention as eco-friendly alternatives to synthetic pesticides due to their natural compounds like essential oils and extracts, which pose minimal risks to non-target organisms and the environment. Mesosphaerum suaveolens (L.) Kuntze, traditionally used as an insect repellent by Bodo tribe of Assam, was evaluated for its insecticidal efficacy against Culex quinquefasciatus, a prevalent mosquito in the region. The methanolic extract of the leaves of M. suaveolens showed significant insecticidal activity with LC₅₀ value at 81.28 μg/mL & LC₉₀ at 186.21 μg/mL. The GC–MS analysis revealed presence of 13 compounds out of which 11 are newly reported in M. suaveolens. For in-silico investigation, the phytochemicals identified from GC–MS analysis were investigated for their binding affinity to selected target proteins of Cx. quinquefasciatus namely: maltase 1 (Cqm1) and Odorant binding protein (OBP). Molecular docking studies predicted five potent inhibitors of the targeted proteins, and highlighted 7-Hydroxy-7, 8, 9, 10-Tetramethyl-7, 8-Dihydrocyclohepta [D, E] Naphthalene as the most promising compound. The MD simulation of two complexes “7-Hydroxy-7, 8, 9, 10-Tetramethyl-7,8-Dihydrocyclohepta [D, E] Naphthalene & maltase 1 (Cqm1)” and “7-Hydroxy-7, 8, 9, 10-Tetramethyl-7,8-Dihydrocyclohepta [D, E] Naphthalene & Odorant binding protein (OBP)”, showed that the compound 7-Hydroxy-7, 8, 9, 10-Tetramethyl-7,8-Dihydrocyclohepta [D, E] Naphthalene has a stronger inhibitory potential against maltase 1 (Cqm1) as compared to Odorant binding protein (OBP). This study underscores the potential of M. suaveolens as an effective, sustainable alternative to synthetic insecticides for controlling Cx. quinquefasciatus.