Antibacterial effects of two Iranian plant extracts and their synergistic effects on Staphylococcus aureus in laboratory medium

The aim of this work was to evaluate the antimicrobial effects of wild garlic (Allium hirtifolium Boiss.) and peppermint (Mentha piperita L.) extracts and their combination on Staphylococcus aureus. In the present work the antimicrobial effects of the mentioned plant extracts were evaluated using disk diffusion method as a preliminary step and microdilution method. The mentioned extracts were introduced into TSB Broth at ten concentrations from 50% to 0.09%(v/v) in order to determine minimum inhibitory concentration (MIC) for Staphylococcus aureus using Bioscreen C device, which is based on optical density measurements. Results indicated that wild garlic and peppermint extracts showed MIC of 3.17%%(v/v) and 12.5%(v/v) respectively for Staphylococcus aureus.The antimicrobial activity was enhanced in response to extract mixture than individual extracts of each species, as no growth was observed at the concentrations from 50 to 0.09%(v/v). In conclusion, edible plants can be a potential source for inhibitory substances for some pathogens. Both extracts studied in this research were effective on Staphylococcus aureus and the combination of them showed synergistic effect on the inhibition of the growth, so the potential of plant extracts when combined with eachother can be used as a more effective barrier for preservation.

Keywords: antimicrobial, extract, Staphylococcus aureus, Mint, Wild Garlic