Biological Activities of Peppermint (Mentha Piperta L.) Oil

Background: Mentha piperta L. var peppermint oil is one of the most important essential oil products in the world due to its application in the pharmaceutical, food, and cosmetic industries. Objective: The present study aimed to examine the biological activities, including antioxidant and antimicrobial potentials of oil extracted from peppermint leaves using a solvent extraction method. Methods: The oil extraction was done in the Soxhlet apparatus using hexane as a solvent. The antimicrobial experiment was conducted as three factor experiment involving one source extract, hexane as a solvent, and four test pathogens completely randomized in three replications. Results: The results of physicochemical properties of peppermint oil indicated that oil yield (41.15%), specific gravity (0.90), acid value (1.54mg/g), free fatty acid (0.78%), and peroxide value (3.70). The antioxidant activities were assessed based on ascorbic acid content, DPPH, and hydrogen peroxide free radical scavenging activities. The M. piperita leaf oil was recorded with ascorbic acid content (45.56%), 2,2-diphenyl-1-picrylhydrazyl DPPH (9.50%) and hydrogen peroxide free radical scavenging activity (78.30%). The mean zone of inhibition against bacterial pathogens ranged from 11.80±0.42 mm to 16.75±0.35mm, while 14.65±0.50to 16.75±0.28mm against fungal pathogens. The oil extract exhibited the strongest bactericidal activity with MIC (0.03μl/ml) and the corresponding MBC (0.06 μl/ml) against S. aureus for antifungal activity. C albicans was the most susceptible to MIC (0.12μl/ml) and MFC (0.25μl/ml). Conclusion: The result of this study was that the physicochemical properties and antioxidant activities of peppermint oil extract demonstrated the quality and stability of the oil extract.