Characterization of pennyroyal (Mentha pulegium) essential oil as an herbal, antibacterial, and antioxidant substance

The aim of this in vitro study was to assess hydro-distillated Mentha pulegium essential oil (MPE) by composition, antioxidant capacity, and antibacterial properties and compared these indexes with synthetic antibiotics and antioxidants. The essential oil active ingredients determined by GC mass procedure while antioxidant activity determined by DPPH technique. Furthermore, by applying four bacterial strains (Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus, and Bacillus cereus), antibacterial properties of pennyroyal was distinguished by disk diffusion, MIC, and MBC methods in different concentrations. The results showed that pennyroyal essential oil has 29 constituents so that cis-pulegone oxide, (E)-p-mentha-2-en-1-ol, and 3,3′-dimenthol being the main components. In addition, strong antimicrobial activity against all four microorganisms tested, especially on Gram positive bacteria, was distinguished, even though it was more effective in higher doses. Besides, the essence was able to reduce the stable free radical DPPH with an IC50 of 1.027 mg/mL while BHT was 20.280 μg/mL. In conclusion, pennyroyal essential oil can be a good substitution for some synthetic antibiotics and antioxidants.