Antibacterial and antioxidant activities of Mentha piperita L.

The antibacterial activity of peppermint oil and different extracts of Mentha piperita against some Gram-positive and Gram-negative bacterial strains was evaluated in the present research work by agar well diffusion method. It was found that the distilled concentrations of essential oil inhibited the growth of microorganisms and the results were comparable with those of antibiotic gentamycin. Essential oils showed a wider spectrum of activity but less strong inhibition as compared to the investigated commercial antibiotic. Minimum inhibitory concentrations (MICs) for the bacterial species ranged from 0.4% to 0.7% v/v. The oil and extracts also exhibited significant antioxidant activity and the oil showed about half potency when compared to the standard BHT. These results indicated the strong antibacterial and antioxidant activities of peppermint oil but additional investigations need to be performed in order to confirm the safety of these concentrations (MIC) for human consumption. Peppermint oil could be used as a good conservation agent by inhibiting some food borne pathogens. (C) 2011 Production and hosting by Elsevier B.V. on behalf of King Saud University.