Investigation of Essential Oil Composition Variation with Age of Eucalyptus globulus Growing in Ethiopia

Abstract

Various types of aromatic and medicinal plants are available in Ethiopia from which the essential oil can be extracted for different purpose. Eucalyptus plant is most common among them. Despite its availability the variation of essential oils of Eucalyptus globulus with ages, the chemical constituents of Eucalyptus globulus essential oil of Ankober origin has not previously been examined. Thus, the aim of this study is to assess the variation of essential oil with ages in Eucalyptus globulus tree grown at Ankober district, Ethiopia. Most part of Ankober is covered by Eucalyptus globulus, locally known as ‘Nech-Baharzaf’. Essential Eucalyptus leaves having different ages were collected and subjected to steam distillation to determine the quality and quantity of essential oil (main components of the oils). Eucalyptus globulus leaves aged 3, 5, 8, 12, 20, 35 and 100 were compared. All the leaves were collected from the same agro-ecological zone and in the same season to avoid oil content variation with climate change and agroecology. Chemical composition of the essential oils was analyzed by GC/MS and alpha-Pinene, dlimonene and cineol were the main constituents. The highest amount of eucalyptol (73.90%) presented in plant aged 100 years whereas alpha-Pinene (20.05%) and d-limonene (6.17%) detected in essential oil of plants aged three. The main constituent of the oil is cineole, ranging from 61.04%-73.90% which might suggest age variation has significant impact on essential oil content composition.