Essential oil composition of four Artemisia species from Ethiopia
The essential oil composition of four Artemisia species, namely A. schimperi Sch. Bip. ex Engl. A. abyssinica Sch. Bip. ex A. Rich., A. afra Jacq. ex Willd., and A. absinthium L. (previously called A. rehan) from Ethiopia has been studied. The essential oil obtained from A. absinthium (seedling from Europe) grown in two places in Ethiopia (Addis Ababa and Butajira) was also analyzed for comparison. Morphological study on the leaves of A. absinthium L. from Ethiopia (previously called A. rehan) and A. absinthium (from Europe) was also conducted. The essential oils were obtained by hydrodistillation using a Clevenger apparatus and analyzed by capillary GC and GC/MS. Forty three compounds representing 76 to 94% of the oils were identified. The composition of the essential oils of A. schimperi, A. afra and A. abyssinica are mainly dominated by irregular monoterpenes: yogomi alcohol (13.5-37.6%), artemisyl acetate (12.7-35.5%), and artemisia ketone (2.3-13.2%). The composition of the oil of A. absinthium (previously A. rehan) however, differs from the other three species in having camphor (21.2-28.3%) and davanone (21.3-26.5%) as major components. The composition of A. absinthum (Europe) was found to have β-thujone (42.3-66.4%) and chamazulene (11.3-24.2%) as major components. The study indicated that the composition of the essential oil of A. absinthium (previously A. rehan) is not only different from the other three species but also from A. absinthium from Europe and does not belong to any of the chemotypes described for the species in the literature. The morphological study on the leaves also showed that it differs from that of A. absinthium from Europe.
KEY WORDS: Artemisia schimperi, A. afra, A. abyssinica, A. absinthium, A. rehan, Asteraceae, Essential oil, Lyratyl isovalerate, Camphor, Davanone
Bull. Chem. Soc. Ethiop. 2015, 29(1), 123-128