Evaluation of the Antibacterial Activity of a Sizable Set of Essential Oils
Health issues related to bacterial infections, and the rise of bacterial resistance, have pushed the need for improved control options. Recently there has been a renewed interest in testing essential oils as antimicrobials, and combinatorial therapy combining conventional antibiotics and essential oils is ongoing. The popularity of essential oils as homeopathic remedies has increased in recent years due to the thought that natural products might prove safer than ingredients currently in consumer products. Several scientific reports exist relating to the efficacy of essential oils in controlling microbes, however most of these publications are either microbe centric, or are specific to one particular essential oil or oil constituent. This work was undertaken to develop a more comprehensive picture of the antibacterial effects of essential oils by evaluating the effectiveness of a large panel of essential oils against four diverse strains of bacteria (Escherichia coli, Staphylococcus aureus, Micrococcus luteus, and Serratia marcescens). Of the essential oils tested, cinnamon bark, lemongrass, oregano, and thyme oils were the most potent, and had activity comparable to a concentration of a penicillin-streptomycin solution commonly used to inhibit bacterial growth. This study supports the idea that certain essential oils could play an important role in the development of antimicrobial products.