Chemical Composition of Clove and Fennel Seed Essential Oils and a Comparison of Their In Silico and In Vitro Antibacterial Activity with That of Their Main Compounds.

Abstract

This study aimed to assess the chemical composition and antibacterial potential of essential oils (EOs) from two plants: clove buds (Syzygium aromaticum) and fennel seeds (Foeniculum vulgare) EOs. The major compounds, eugenol and estragole, were isolated from these oils and tested against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The EOs were obtained via hydrodistillation and analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Clove oil was found to be rich in eugenol (68.51%), while fennel seed oil was dominated by estragole (93.30%). Antibacterial activity, assessed by the agar disc diffusion method and supported by MIC/MBC testing, revealed that eugenol exhibited the highest efficacy, with MIC values ranging from 0.58 to 1.15 mg/mL and MBC values from 1.15 to 2.30 mg/mL, particularly against S. aureus and P. aeruginosa. In silico analysis was conducted to evaluate pharmacokinetics, toxicity, and molecular docking interactions. ADME predictions indicated good oral bioavailability and high membrane permeability for both compounds, with eugenol displaying superior solubility and better compliance with Lipinski's Rule of Five. Molecular docking simulations confirmed the antibacterial potential, with eugenol showing stronger binding affinities to bacterial targets (-7.8 kcal/mol), forming more stable and diverse interactions compared to estragole. However, toxicity predictions indicated potential mutagenic, carcinogenic, and cardiotoxic (hERG inhibition) risks for both compounds.