Chemical Characterization, In Silico Investigations, In Vitro Evaluation of Allelopathic Potential and Insecticidal Activity of <i>Laurus nobilis</i> L. Essential Oil

Our work aims to study the allelopathic, insecticidal, and repellent activities of the essential oil (EO) extracted from the leaves of Laurus nobilis. The chemical composition of the EO was analyzed by gas chromatography-mass spectrometry (GC-MS). The herbicidal effect was tested on Hordeum vulgare, Raphanus sativus, and Lactuca sativa. Fumigant and repellent activity bioassays against the stored grain insect Tribolium castaneum (Herbst, 1797) were investigated in vitro. In addition, molecular docking simulations of the identified phytocompounds against Arabidopsis thaliana HPPD (PDB: 6j63) and odorant-binding protein from the Southern House Mosquito (pdb:3ogn) were performed. GC-MS analysis reveals a total of 30 compounds that accounted for 94.03% of the oil. The most abundant compounds identified were 1,8-cineole (19.41%), β-Elemene (9.75%), and α-Terpinyl acetate (8.99%). The EO of L. nobilis was highly phytotoxic on seed germination and seedling growth of crops tested. The EO, with a dose of 93.524 µL/L, was sufficient to kill 50% of insects after 24 h of treatment. And it has a repulsion percentage of 60%-80%. The docking outcomes show significant intermolecular interactions, especially with β-Elemene, Bicyclogermacrene, and γ-Muurolene. The results obtained suggest that this medicinal plant is a valuable source of volatile substances with promising insecticidal and allelopathic activities.