Chemical Composition of the Essential Oils of Four Cultivated Eucalyptus Species in Iran as Medicinal Plants (E. microtheca, E. spathulata, E. largiflorens and E. torquata)

The leaves of four cultivated Eucalyptus species, Eucalyptus microtheca var. Microtheca F. Muell., Eucalyptus spathulata, Eucalyptus largiflorens and Eucalyptus torquata were collected in spring from Kashan and Isfahan provinces (central region of Iran). After drying the plant materials in shade, their essential oils were obtained by hydro-distillation. The oils were analyzed by capillary gas chromatography, using flame ionization and mass spectrometric detection. Twenty-two components were identified in the oil of Eucalyptus microtheca with 1,8-cineole (34.0%), p-cymene (12.4%), ?-pinene (10.7%) and ?-pinene (10.5%) as main constituents. Twenty-one compounds were identified in the oil of Eucalyptus spathulata with 1,8-cineole (72.5%) and ?-pinene (12.7%) as main components. Twenty-six compounds were characterized in the oil of Eucalyptus largiflorens with 1,8-cineole (37.5%), p-cymene (17.4%) and neo-isoverbenol (9.1%) as main components. Sixteen compounds were characterized in the oil of Eucalyptus torquata with 1,8-cineole (66.9%) ?-pinene (13.9%) and trans-pinocarveol (6.3%) as main constituents. The results showed that although the 1,8-cineole was the main component of the essential oils of all Eucalyptus species, but its relative content was higher in the oil of Eucalyptus spathulata and Eucalyptus torquata.