Essential Oil Composition, Antibacterial and Antioxidant Activities of Mentha aquatica Growing in Ethiopia

Abstract

The in vitro antibacterial and antioxidant activities of the essential oil of Mentha aquatica L. (Lamiaceae) growing in Ethiopia were studied. The chemical composition of the oil was also investigated by using capillary gas chromatography-mass spectrometry. A total of 34 compounds representing 99.4% of the oil have been identified. Menthofuran (70.5%) was characterized as the main component with limonene and pmenthone constituting 9.42 and 7.20% of the oil, respectively. In general, the oil showed a remarkable activity against the Gram-positive bacteria tested of which Staphylococcus aureus 29737, S. aureus ML267, Sarcina luteus 9341 and Bacilus pumilus 8241 strains were the most susceptible. The minimum inhibitory concentration (MIC) values of the oil against these organisms were found to be less than 5 μg/ml. The antioxidant activity of the oil was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and deoxyribose degradation assays and was found to possess good radical scavenging activity with IC50 values of 11.2 and 3.74 μl/ml, respectively. Keywords: antibacterial, antioxidant, Mentha aquatica, essential oil, capillary gas chromatography-mass spectrometryEthiopian Pharmaceutical Journal Vol. 26 (1) 2008: pp. 9-16