Comparison of antimicrobial effects of rosemary (Rosmarinus officinalis L.) extract and essential oil on plant’s pathogens (Xanthomonas compestris and Pseudomonas syringe) and human’s pathogens (Staphylococcus aureus and Escherichia coli)

Rosemary (Rosmarinus officinalis L.) is a valuable medicinal plant. This study aimed to compare the chemical composition and antimicrobial effects of rosemary metabolic extract and essential oil against plant and human pathogens.

The compounds of methanolic extract and rosemary leaf essential oil were identified by GC-Mass and the antibacterial effects of essential oil and extract were measured by disk diffusion method and the minimum inhibitory concentration (MIC) of rosemary essential oil and extract was measured. Analysis of variance and Duncan's test were used for statistical evaluation of data.

Alpha-Pinene, Verbonone, Bornyl acetate, Camphor, Limonene, Caryophyllene, beta-pinene, beta-Myrcene, L-borneol, Camphene are the main constituents of extract and alpha-pinene, camphor, bornyl acetate and eucalyptol, Camphene, Caryophyllene, Limonene, beta-pinene were the main essential oil of rosemary leaf. Rosemary extract showed the highest and lowest inhibitory effect against Escherichia coli and Xanthomonas compestris. In the case of Staphylococcus aureus, Pseudomonas syringe, and Xanthomonas compestris, the results show that the essential oil has the same inhibitory ability against these three strains, and the ability of the extract to inhibit human pathogens is significantly higher than that of plant pathogens. Rosemary extract and essential oil can be used as a solution to eliminating plant and human diseases.