Insecticidal Potential of Juniperus phoenicea Essential Oil against Callosobruchus maculatus: Chemical Composition, Biological Evaluation, and Molecular Docking Analysis

Abstract

Currently, biopesticides derived from essential oils (EOs) are gaining attention as eco-friendly alternatives to synthetic pesticides. This study aimed to investigate the chemical composition and insecticidal properties of Juniperus phoenicea EO. Essential oil was obtained from Juniperus phoenicea leaves by hydrodidtillation. The chemical constituents of the EO was identified by Gas chromatography-mass spectrometric (GC-MS) analysis The insecticidal activity of the EO was evaluated by contact and inhalation tests against the chickpea weevil Callosobruchus maculatus. The potential mechanisms of the insecticidal activity of the EO was elucidated by in silico molecular docking study. Juniperus phoenicea EO was obtained at a yield of 1.10%. GC-MS analysis identified 30 compounds, with α-pinene (43.61%) and manoyl oxide (11.50%) as the major components. In vivo tests on Callosobruchus maculatus showed significant insecticidal effects of the EO, with lethal doses (LC50) of 24.11 μL/L and 26.79 μL/L for inhalation and contact exposure, respectively, after 96 hours. The EO also reduced oviposition and adult emergence by 23.65% and 27.16%, respectively at 20 μL/L. In silico molecular docking identified caryophyllene oxide as the most active compound against acetylcholinesterase (PDB: 6ARY) with a glide score of -7.209 kcal/mol. Myrtenal showed the highest efficacy against juvenile hormone (PDB: 5V13) with a glide score of -7.116 kcal/mol, while rosifoliol demonstrated notable activity against chitin synthase 2 (PDB: 7STM) with a glide score of -5.848 kcal/mol. These findings highlight the potential of J. phoenicea EO as a sustainable, natural bioinsecticide to control C. maculatus, offering an environmentally friendly alternative to synthetic pesticides.