Decoding Antimicrobial Activities of Peppermint (Mentha Piperita), Tea Tree (Melaleuca Alternifolia), and Eucalyptus...

Essential oils are popular for their antimicrobial properties. In the present study, the antibacterial activities of peppermint (Mentha piperita), tea tree (Melaleuca alternifolia) and eucalyptus (Eucalyptus globulus) essential oils were evaluated using both in vitro and in silico approaches. The activities were tested against both Escherichia coli and Staphylococcus aureus using disc diffusion analysis, minimum inhibitory concentration, and minimum bactericidal concentration assays. Furthermore, the interaction of the selected essential oil's major constituents, including terpinen-4-ol, menthol, and 1,8-cineole, with the highly conserved ribosomal protein uS12 was identified by molecular docking analysis. Peppermint oil showed the highest activity and selective efficacy toward Staphylococcus aureus, while tea tree oil was more effective against Escherichia coli. Molecular docking results revealed that major constituents like menthol and terpinen-4-ol could mimic gentamicin's binding profile, specifically destabilizing the uS12 N-terminal domain and Arg86 to impair translational accuracy which might be resulted in antimicrobial activity through translation inhibition. The results provide a structural basis for these essential oils as potent natural inhibitors of bacterial protein synthesis.