Identification of Essential Oil Components, Total Phenolic Content and Antioxidant Properties of Mentha aquatica in Southern Khorasan Province, Iran

Many medicinal plants have natural antioxidant properties. In this study, the chemical composition of Mentha aquatica L. essential oil was determined and antioxidant properties of essential oils and methanolic extracts, ethanolic extracts, acetonic extracts and aqueous extracts were studied. Also, Phenolics, flavonoids and tannins contents of all the mentioned extracts were determined. The essential oil of the dried flowering aerial part of wild water mint is extracted by hydrodistillation. The essential oil was analyzed by capillary GC and GC-MS. The Folin–Ciocalteu method was adopted to determine the total phenols content while flavonoids were estimated according to the aluminum chloride colorimetric method. To evaluate tannins content, vanillin and HCl were added to the extracts. The antioxidant potential was measured by 1, 1-diphenyl-2-picrylhydrazyl radical scavenging and the inhibition of β-carotene bleaching assays. The main components of essential oil were pipritenone oxide (37.80%), 1, 8-cineole (24.13%), α-gurjunene (11.96%) and pulegone (4.64%). The antioxidant properties of the essential oil were more considerable than all the other extracts. The antioxidant properties and total phenolics, flavonoids and tannins contents of methanolic extracts, ethanolic extracts and acetonic extracts were larger than the aqueous extract. These results show that essential oils, methanolic extracts, ethanolic extracts and acetonic extracts of M. aquatica from Southern Khorasan of Iran have a great potential of polyphenols which can be used as a natural food preservative and antioxidant source.