Investigating the Antibacterial Effects of Cuminum cyminum and Foeniculum vulgare Essential Oils on Escherichia coli and Listeria monocytogenes

Background: Due to the increasing demand for new antibiotics, extensive research is being conducted on various compounds, particularly plant-based compounds. Among them, plant essential oils (EOs) have been investigated for their antibacterial properties in numerous studies. Accordingly, the inhibitory and bactericidal effects of Cuminum cyminum and Foeniculum vulgare EOs on two bacterial species, Escherichia coli and Listeria monocytogenes, were examined in this study. Methods: The compounds present in these extracts were evaluated using gas chromatography-mass spectrometry analysis. Subsequently, molecular docking methods were employed to depict the interactions of these compounds with the active site of the beta-lactamase enzyme of these bacteria in three-dimensional illustrations. Results: Laboratory methods such as disk diffusion agar, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) revealed that although the bactericidal properties of these extracts were weak, they exhibited strong growth inhibitory properties, particularly the effect of F. vulgare EO on L. monocytogenes (MIC=۱/۱۰۴). Additionally, with the presence of p-cumin aldehyde at ۳۳.۷% in the cumin extract and trans-anethole at ۴۶.۵% in the fennel extract, molecular docking analyses showed that the binding ability and antibacterial properties of the cumin extract against E. coli by two hydrogen bonds and fennel extract against L. monocytogenes by two hydrogen bonds were more pronounced considering the level of binding energies. Conclusion: Although the extracts represented weak bactericidal properties, their strong inhibitory effects on bacterial growth, especially with F. vulgare EO on L. monocytogenes, are notable. Moreover, the active compounds, such as p-cumin aldehyde and trans-anethole, demonstrated significant potential as alternative antibacterial agents.