Chemical components of essential oils of four Eucalyptus L'Her. species cultivated in Kashan’s botanical garden, Iran

Eucalyptus L'Her. [an aromatic genera of the family (Myrtaceae)] is native to Australia and other tropical species is planted worldwide. The purpose of this study is to extract and identify the essential oils components of four species of Eucalyptus L'Her. cultivated in botanical garden of Kashan, Central Iran. Leaves of E. largiflorens, E. intertexta, E. torquata and E. loxophleba, were collected from the botanical garden in Kashan. Extracting was done by hydro-distillation method and Clevenger approach. Components of essential oils were identified using GC and GC/MS analysis. The essential oil yield of E. largiflorens was 1.85% (v/w) and, nineteen compounds were identified. The major components in the essential oil were 1,8-cineol (58.71%), p-cymene (12.42%), α–pinene (5.61%) and terpinen-4-ol (4.53%). Yield of the essential oil of E. intertexta was 1.5% (v/w) and, sixteen components were identified which the major components were 1,8-cineol (69.45%), α–pinene (14.26%), globulol (4.02%) and terpinen-4-ol (1.79%). Yield of the essential oil of E. torquata was 1.2% (v/w) and, twenty components were identified which the main compounds were 1,8-cineol (33.86%), α–pinene (26.14%), aromadendrene (8.99%) and globulol (7.28%).  The essential oil yield of E. loxophleba was 1.54% (v/w) which the major components were identified including 1,8-cineol (25.71%), globulol (21.63%), aromadendrene (20.43%) and 4-metyl-2-pentyl acetate (14/98%). The highest amount of terpenoides in essential oil of leaves E. largiflorens, E. intertexta, and E. torquata were monoterpenes, while the highest amount of terpenoides in essential oil of E. loxophleba were sesquiterpenes. According to the results of this research and the value of different species of medicinal Eucalyptus L'Her essential oils (in particular, the combination of 1,8-cineol), cultivation and exploitation of E. intertexta for pharmaceutical industry is recommended.