Evaluation of antimicrobial and antioxidant activity of essential oil of Mentha piperita

Abstract Background: Increasing drug resistance to antibiotics in most bacteria has led to the development of natural antimicrobial compounds. Peppermint (Mentha piperita L.) is one of the most widely used herbs that has many therapeutic effects. The purpose of this study is the evaluation of antimicrobial and antioxidant activity of essential oil of Mentha piperita L. Materials and Methods: In this study, after collection and drying of leaves, essential oils of the plant was extracted using a solvent-free microwave extraction. The compounds of essential oil were identified by the GC-MS (Gas chromatography-mass spectrometry). The effect of antioxidant was determined by beta-carotene test and antimicrobial activity was carried using agar-dilution method also, the minimum inhibitory concentration (MIC) value was evaluated. Results and discussion: Menthol, Menthofuran, and 1S-Neomenthyl acetate were the major compounds of essential oil of Mentha piperitaL.collected from Marivan, respectively that menthol is the main compound of essential oil. The essential oil was more effective on gram-positive bacteria (Staphylococcus epidermidis, Bacillus subtilis, Staphylococcus aureus) and gram negative (Shigella dysenteriae, Klebsiella pneumonia) also had a good antioxidant activity compared to the standard BHT (butylated hydroxytoluene). Due to its relatively good antimicrobial and antioxidant properties, it can be used in the pharmaceutical and food industries.