In vitro assessment of antimicrobial activity in various commercial essential oils

This study investigated the antimicrobial activities of four commercially available essential oils: common centaury (Centaurium erythraea), juniper (Juniperus communis), basil (Ocimum basilicum) and clove (Syzygium aromaticum). Each essential oil was tested against four different microorganisms: Staphylococcus aureus, Escherichia coli, Proteus mirabilis, and Candida albicans, using the agar disk diffusion method. Among the tested microorganisms, clove oil exhibited the highest antimicrobial activity. Clove oil demonstrated pronounced antimicrobial effects particularly against Candida albicans, while also showing significant inhibition against the bacterial strains. Basil oil showed strong antimicrobial activity against Candida albicans as well. In contrast, juniper oil displayed limited antibacterial activity, and common centaury oil was ineffective against the tested microorganisms. The findings highlight the potential of clove essential oil as a natural antimicrobial agent. Furthermore, the results emphasize the importance of quality control and standardization to ensure the consistency of biological activities in commercial essential oil products.