Identification of chemical compounds in essential oils from stems, leaves and flowers of Mentha longifolia Var. kermanensis by GC/MS

Abstract

The genus Mentha, which belongs to the Labiatae family with the Persian name of “Poonehsa” includes 6 species in Iran. In this study, Mentha longifolia Var. kermanensis was collected from North of Kerman Province in April 2013. After collecting plant material, botanical identification and suitable drying, the essential oils of stems, leaves and flowers of Mentha longifolia Var. kermanensis were separately extracted using hydrodistillation method and analyzed by GC and GC/MS. GC/MS analysis was performed using a Hewlett-Packard 5973 mass spectrometer coupled to a Hewlett-Packard 6890 gas chromatograph equipped with a HP-5MS capillary column (5% phenyl methyl polysiloxane, 30 m ×0.25 mm, film thickness 0.25 µm). The carrier gas was helium. MS were taken at 70 eV. The air-dried stems, leaves, and flowers of the plant yielded 1.2%, 1.5% and 1.8% (w/w) (respectively) of a light yellowish colored oil. Identification of the constituents of the oils were done by comparison of their mass spectra and retention indices with those given in the literature and those authentic samples. Sixteen compounds (92.8%) were identified in the Stem oil, with Piperitenone (23.6%), α-Bisabolol (16.4%) and 1,8-Cineole (15.3%) as the main constituents. Also, among the 13 identified compounds (98.9%) in the Leaf oil, Piperitenone (35.8%), 1,8-Cineole (28.2%) and Piperitenone oxide (16.6%) were found to be the major components. Furthermore, Piperitenone (40.6%), Piperitenone oxide (28.0%) and 1,8-Cineole (19.5%) were the main constituents among the 13 compounds (97.0%) characterized in the flower essential oil.