Formulation and evaluation of Syzygium aromaticum essential oil nanoemulsion: Effects on Tribolium castaneum, wheat growth, and molecular docking for pest control

Abstract

The nanoemulsion was prepared using ethanol (3%), the biosurfactant Tween 80 (5%), and water (80%), which together constituted 20% (v/v) of the nanoemulsion. The toxicity of Syzygium aromaticum (clove) essential oil nanoemulsion was evaluated against the population of Tribolium castaneum in terms of LC50 (lethal concentration), which was determined to be 112.93 ppm. The impact of the clove essential oil nanoemulsion formulated at LC50 on wheat germination and seedling growth was assessed using a pot test. Results showed that the treatment inhibited wheat seedling growth and reduced the overall growth rate. Additionally, the metabolites of adult T. castaneum beetles were analyzed following exposure to a sub-lethal concentration (LC20) of the clove oil nanoemulsion. The sub-lethal dose significantly decreased glycogen and glucose levels in all adult beetles while increasing invertase activity and total protein in resistant populations throughout the exposure period. These metabolic changes highlight the biochemical impact of the nanoemulsion. A molecular docking study was conducted to predict the mode of action of the major components of the essential oil and nanoemulsion, namely eugenol and α-humulene, at the binding site of the enzyme alkaline acid phosphatase of Tribolium castaneum. The results provide insights into the molecular interactions between insect-plant compounds and their effects at the biochemical level. These findings suggest the potential of clove essential oil nanoemulsion as a natural, eco-friendly solution for sustainable pesticide management in stored grain facilities. Furthermore, the study emphasizes the need to understand the side effects on both animals and humans to ensure safe applications