ANTIBACTERIAL ACTIVITY AND CHEMICAL COMPOSITION OF THE LEAF ESSENTIAL OIL OF MENTHA ROTUNDIFOLIA FROM MOROCCO

The essential oil of the leaves of Mentha rotundifolia grown in Morocco was determined by hydrodistillation method and analysed by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS). The antimicrobial activities were tested in vitro by in a bioassay on nine bacterial strains: Escherichia coli, Staphylococcus aureus, Staphylococcus intermedius, Klebsiella pneumonia, Pseudomonas aeruginosa, Bacillus subtilis, Streptococcus mutans, Micrococcus luteus, and Proteus mirabilis and were evaluated using two different methods; agar disc diffusion and minimum inhibitory concentration (MIC). The results of the study revealed that essential oil yields and the total oil of Mentha rotundifolia were 1.54% and 90.40%. The major component was menthol (40.50%), other predominant constituents were: menthone (5.0%), menthyl acetate (4.50%), menthofuran (4.20%), oxyde de piperitone (3.80%), linalyl acetate (3.50%), neomenthol (3.20%), piperitone (3.10%), isomenthone (2.50%), 1,8-cineole (2.40%), linalool (2.0%), limonene (1.80%), geraniol (1.70%), myrcene (1.60%), geranyl acetate (1.50%) and trans-Sabinene hydrate (1.40%). Essential oil extracted from Mentha rotundifolia showed the highest activity against Escherichia coli, Staphylococcus aureus, Staphylococcus intermedius, with the strongest inhibition zone 45, 34 and 31mm respectively.