In vitro antimicrobial effect of Rosmarinus officinalis leaf extract against some pathogens

Today، the increased use of antibiotics lead to the incidence of resistant strains thus، Antimicrobial drugs that have fewer side effects than antibiotics، they are less available. Rosemary is a medicinal plant that has many uses in traditional medicine. In this study، methanol leaves extract of this plant are tested on various pathogens. In this in vitro study Rosmarinus was used to evaluate the antimicrobial effects on pathogen. Methanol extract of the leaves of this plant، with concentrations of 400، 200، 100 and 50 mg per liter were prepared، and antibacterial activities were evaluated by well diffusion method on strains of Escherichia coli، Pseudomonas aeruginosa، Bacillus cereus and Staphylococcus aureus. minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was determine by the microplate method. In this study، Ethanol extract of rosemary leaves at concentrations of mg/ml400 was active against Pseudomonas aeruginosa and Escherichia coli. Minimum Inhibitory concentration of the extract on the growth of these bacteria from 6/25 to mg/ml100 was change. Also MBC of extract showed range from 12/5 to 200 mg/ml respectively. It was found that، rosemary extract inhibited growth of Staphylococcus aureus، Escherichia coli and Pseudomonas aeruginosa but not inhibited growth of B. cereus