Evaluation of essential oil composition and antibacterial effect of Mentha longifolia ‎collected from different region of Lorestan province

The aim of this study was to investigate of the chemical composition of the essential oil extracted from Mentha longifolia collected from different regions of Lorestan province (Khorramabad, Aleshtar, Delfan) and to determine the antibacterial activities against three certain bacterial strains (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli). The chemical profiling of the essential oil was performed using gas chromatography-mass spectrometry (GC-MS) analysis. GC-MS analysis revealed that essential oil of M. longifolia from Khorramabad region was constituted by pulegone (54.41%) and 1, 8-cineole (22.05%) as a major component. M. longifolia from Aleshtarwas rich in piperitenone (29.29%), pulegone (17.53%), piperitenone oxide (14.35%), 1, 8-cineole (14.34%) and the main component of M. longifolia from Delfanwas citronelyll acetate (59.93%), aromadrene (5.1%), respectively. A significant correlation between geographical and soil characteristics, except phosphorus and electrical conductivity, with the essential oils components was detected. The results obtained using MIC and MBC showed that the minimum inhibitory concentration of the essential oil of M. longifolia from studied regionwas in the range of 0.03-2 mg/mL. The most effective essential oil in bacterial inhibition for E. coli and S. aureus bacteria was the essential oil from Aleshtar and Delfan, respectively. Two bacteria P. aeruginosa and S. aureus were least susceptible to M. longifolia essential oil from Khorramabad region. The essential oil of M. longifolia from different regions of Lorestan provinc exhibited low to high inhibitory activity against gram-positive and negative bacteria,.which depended to the region of collected plants and studied bacterial strains. In this research, three components citronellyl acetat, citronellal and aromandrene was detected in M. longifolia essential oil for the first time