Bioactive potential of stinging nettle, round-leaved mint, and crowned chrysanthemum extracts against Tuta absoluta: Chemical characterization and molecular docking insights

Abstract

Tuta absoluta is among the most devastating pests affecting tomato crops and has the potential to cause significant yield losses. The restrictions on pesticide usage in plant pest management, owing to the potential health hazards and the impact of pesticides on the environment, have prompted research into various alternatives, including natural products such as biopesticides (plant extracts). The purpose of this study was to determine the chemical composition and assess the insecticidal activity of three medicinal plants, namely, Urtica membranacea , Chrysanthemum coronarium and Mentha rotundifolia, against T. absoluta larvae via a contact toxicity assay. The quantitative analysis demonstrated that the methanolic extracts presented high levels of polyphenols, flavonoids and tannins. Analysis of phytochemical constituents via gas chromatography–mass spectrometry (GC–MS) revealed significant variability in chemical composition between the different species studied. The stinging nettle extract was characterized primarily by phytol, linolenic acid methyl ester, neophytadiene, photochemical A and palmitic acid methyl ester. In contrast, the round-leaved mint extract contained mainly cyclobutane acetonitrile, 1-methyl-2-(1-methylethenyl)-, germacrene D and cis-4-thujanol, whereas the crowned chrysanthemum extract was distinguished by the presence of α-farnesene, dehydrohumulinic acid, neophytadiene, 4-dimethylsulfylidene-3-methyl-1-phenyl-2-pyrazolin-5-one and myrcene. The plant extracts exhibited significant insecticidal properties, with mortality rates ranging from 40% to 83.33% for U. membranacea , 37.49% to 76.74% for M. rotundifolia and 39.28% to 76.74% for C. coronarium , indicating notable differences in lethal efficacy and inhibition of larval development against T. absoluta . Molecular docking analyses revealed that dehydro-cohumulinic acid exhibited the strongest binding affinities for both the ecdysone receptor (–7.5 kcal/mol) and acetylcholinesterase (AChE) (–8.9 kcal/mol), suggesting a dual mode of action through interference with hormonal regulation and synaptic transmission in T. absoluta larvae. These results highlight the potential of botanical extracts as biocontrol agents in integrated pest management (IPM) strategies.