Determination of chemical composition and minimum inhibitory concentration and minimum bactericidal concentration of Mentha spicata L. essential oil against Staphylococcus aureus and Escherichia coli

Mentha spicata L. (Peppermint) is a widely used medicinal herb that also as a commonly herb spice has used in the food industry.This study carried out to evaluating of chemical composition and antibacterial activity of the essential oil of Mentha spicata L. (Peppermint) against Staphylococcus aureus and Escherichia coli.Essential oil of the herb leafs was extracted by Clevenger apparatus. Chemical composition of essential oil was identified with a Gas chromatography/mass spectrometry system and then Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of this essential oil were determined using micro-dilution broth method in microplate 96 pits. A total of 33 chemical constituents were identified which contained 98.5% the total of essential oil compounds. The most important components of this essential oil were: carvone (%28.35), menthol (%14.35), methylene (%14.059) and limonene (%9.303). MIC and MBC of essential oil of this herb against the S. aureus 25 and 25 µg/ml and against the E.coli was 50 and 100 µg/ml respectively. Due to antibacterial compounds of essential oil of this plant, it can be used as a natural preservative in food.