Evaluation of the antibacterial activity of essential oil of Laurus nobilis against Pseudomonas syringae pv. phaseolicola and potential biocidal action

Summary With a continuously growing human population on our planet, the chemical burden of our environment is also growing. In addition, the resistance of microorganisms, like bacteria, to widely used chemicals is evident. Therefore, the application of bactericidal products that reduce the risks for development of resistance as well as the environment and human safety is of great benefit. In this work, we have screened the essential oil extracted from plants of Laurus nobilis L. (laurel) grown at the base of the Greek mountain Olympus for its antimicrobial activity against two strains of the Phaseolus vulgaris pathogen, Pseudomonas syringae pv. phaseolicola as well as human pathogenic bacteria (biocidal use). Our results, obtained with established methods, like Well diffusion and Disc diffusion assay, reveal that laurel essential oil is a very effective bacteriostatic and bactericidal agent. Importantly, the activity of laurel essential oil as growth inhibitor of the plant pathogen Pseudomonas syringae pv. phaseolicola is reported for the first time. This opens the field for more extended investigations regarding its use in crop protection. Additionally, the laurel essential oil tested showed significant antibacterial properties against several human pathogenic bacteria, namely Micrococcus luteus, Escherichia coli, Staphylococcus aureus and Bacillus subtilis.