The Effect of Distillation Methods and Harvesting Times on the Volatile Oil and Cineole Content of Eucalyptus dealbata

Abstract

The leaves of Eucalyptus dealbata were collected in the middle of four season (spring, summer, autumn and winter) from Dezful in Khuzistan province (western south of Iran, with dry and warm climate). After drying the plant materials in shade, their essential oils were obtained by hydro-distillation. In addition, the essential oils of plant materials collected in summer, were obtained by water and steam and also direct steam-distillation. The oils were analyzed by capillary GC and GC-MS and compared for their variation. The oil yields of E. dealbata in different seasons were 1.25–1.97 % (the highest in summer and the lowest in spring). Thirty-eight components were identified in the oil of E. dealbata with 1,8-cineole (54.9–70.0 %) as main constituent. The highest percentage of 1,8-cineole was found in winter (70.0 %). In comparing distillation methods, the oil yields were 0.16–1.97 % (the highest for hydro-distillation and the lowest for steam-distillation). The main components in the oils obtained by three different distillation methods were 1,8-cineole (38.4–54.9 %), α-pinene (15.1–23.5 %), α-eudesmol (1.1–12.5 %), globulol (2.2–11.5 %), aromadendrene (1.6–5.3 %) and β-eudesmol ( 1.9–3.6 %). The highest percentage of 1,8-cineole was obtained by hydro distillation method.