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.
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