摘要
Chemical composition of the essential oils (EOs) is dependent on the plant species and varieties, and within the same variety, from geographical region. Knowledge of the factors that determine the chemical variability and yield for each species are very important in particular for commercially important species, to optimize the conditions that may affect yields and quality of essential oils. In addition to the commercial importance of the variability in yield and composition, the possible changes are also important when the essential oils and volatiles are used as chemotaxonomic tools. Therefore it is important to characterize essential oils native to Tanzania for commercial and therapeutic purpose. In the present study we investigated the variation in the yield and chemical composition of the essential oils isolated from air dried leaves of three Eucalyptus species namely Eucalyptus saligna, Eucalyptus citriodora and Eucalyptus camaldulensis collected from two different regions of Tanzania namely Morogoro and Lushoto. The steam-distilled essential oil content of E. saligna, E. citriodora and E. camaldulensis Morogoro were 0.6%(v/w), 1.68%(v/w) and 0.80%(v/w) respectively while from Lushoto are 0.30%, 1.22 and 0.36%(v/w) respectively. Using GC/MS,α-pinene (46.72%) and p-cymene (43.61%) were identified as the most abundant chemical constituents of E. saligna from Morogoro and Lushoto respectively. Citronellal (82.24% and 60.41% respectively) is the main constituents of E. citriodora from Morogoro and Lushoto respectively while p-cymene (52.59% and 64.02%) is the main constituents of E. camaldulensis.
