Investigation of Antibacterial Efficacy of Different Commercially Available Tea Tree Oils

Abstract

Tea tree oil, obtained by steam distillation from the leaves of the Melaleuca alternifolia (Myrtaceae) plant, is an essential oil that has been used as a topical antiseptic for many years, especially in Australia, the country where it grows naturally. The use of alternative treatments in diseases together with medical treatments has gained momentum. The aim of this study is to investigate the antibacterial activities of 10 different commercially available tea tree oils. The antibacterial activities of the oils were determined by disk diffusion method using standard bacterial strains. In the study, it was determined that 6 different essential oils were effective against the bacteria studied, but 4 of them did not form a zone in any bacteria. In general, it was observed that the widest zone diameters were formed in E. coli and K. pneumoniae strains in all essential oils that showed activity, and the activities in gram negative bacteria were better than in gram positive bacteria. In addition, it was determined that only two of the essential oils formed zones in E. faecalis strain. The abundance of positive results in the literature regarding tea tree oil is noteworthy and has the potential to be a good source of therapeutic compounds. However, the fact that the effectiveness of tea tree oils on the market is very different from each other brings up the possibility that the expected effect will not occur when using these oils. The solution to these problems may be to ensure the quality of essential oils with certain standards at every step, from production to sale.