Background and aims: The aim of this study was to find new plant components and study antimicrobial effect of extracts of Satureja hortensis, Stachys lavandulifolia Vahl, and Mentha pullegium on methicillin resistant and methicillim susceptible Staphylococcus aureus bacteria.

Methods: In this descriptive analytic study, Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution in 96-well microplate. The level of phenolic, flavonoid, and flavonol components in the plant extracts was measured and at the end the above values were reported in mg/ml.

Results: The lowest MIC was obtained for S. hortensis extract which was 5 mg/ml for both standard strains. S. lavandulifolia extract with 20 mg/ml MIC had the highest MIC rate for methicillin susceptible S. aureus and, besides M. pullegium extract with 10 mg/ml MIC, had the highest MIC rate for methicillin resistant S. aureus. The lowest MBC was also obtained for S. hortensis which was 5 mg/ml for methicillin susceptible and methicillin resistant S. aureus. The highest MBC for methicillin resistant S. aureus was obtained for M. pullegium extract.
S. hortensis extract contained the highest amounts of phenolic, flavonoid, and flavonol components (14.98, 25.82, 169.37 mg/ml), respectively and this extract’s amount of phenolic components was higher compared to other extracts.

Conclusion: S. hortensis extract contributes greatly to inhibiting the growth of methicillin susceptible and methicillin resistant S. aureus which is due to this extract phenolic components high amount.