The in vitro antimicrobial activity of some essential oils from aromatic plants

Abstract

Essential oils (EOs) are plant secondary metabolites with a wide range of therapeutic effects (antioxidant, antibacterial, antifungal, anti-inflammatory). Thus, this study aims to assess the antibacterial/antifungal activity of six essential oils against Staphylococcus aureus, Escherichia coli strains and Candida albicans yeast, as follows: Oregano oil; tea tree oil; a mixture of oils obtained from clove, cinnamon, lime, rosemary and eucalyptus; Frankincense oil; basil oil; black pepper oil. The antimicrobial activity was assessed by means of agar disk diffusion method. Based on the diameter of inhibition zones and the statistical analyses, our results have shown that the S. aureus strains were highly susceptible to all types of EOs and the biological effect was similar for oregano and basil essential oils. Regarding E. coli, the oregano, basil and tea tree EOs exerted a significant and similar antibacterial effect, while antifungal activity was reported for the tea tree and basil essential oils. Based on our results, we also identified the main active constituents from the analysed samples that appear to be responsible for the antimicrobial activity, in the context of the multicomponent extract.