Anti-bacterial effect of Mentha spicata L. essential oil on eight standard species of gastrointestinal pathogens

Nowadays resistance to antibiotics and their side effects has emerged as a worldwide problem. As a result، tend to use anti-bacterial compounds of plant origin has been increased. Mint plant scientifically called Mentha spicata L. is one of the plants which has many medicinal uses and its antibacterial effects is a matter of debate. We aimed to study antibacterial effects of Mentha spicata L essential oil on 8 standard bacterial species including Escherichia coli، Bacillus cereus، Klebsiella pneumoniae، Pseudomonas aeruginosa، Staphylococcus aureus، Shigella flexneri، and two Salmonella species. In this experimental study، using micro-dilution broth method and reading the results by ELISA reader، minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of mint essential oil were determined against the 8 standard bacterial strains. The lab tests were repeated for three times. The results were analyzed by statistical tests. The MIC for Mentha spicata L essential oil was significantly different among the bacterial species (p <0. 05). The highest growth inhibitory effect was found against Bacillus cereus and the least ones were recorded against Klebsiella pneumoniae and Staphylococcus aureus. No significant difference was found between the bacterial MBCs (p> 0. 05). This study revealed significant and selective antibacterial characteristics for Mentha spicata L suggesting to be used in pharmaceutical and food industries.