Abstract:
Eucalyptus globulus is one of the abundant tree species in Ethiopia known for medicinal
values of its essential oils. The essential oil composition of a given species may vary with
environmental factors. In this study, leaf of essential oil compositions and their antimicrobial
activities were analyzed from E. globulus sampled from Haramaya University (HU) and
Entoto Park (EP). Essential oils were extracted by steam distillation method and their
compositions were analyzed using GC. Antimicrobial activities of the essential oils at
different concentration levels were assessed with streptomycin and dimethyl sulfoxide used as
positive and negative controls, respectively. The results showed that the essential oils from
HU and EP samples contained 20 and 17 terpene compounds, respectively. Chemical profile
of essential oils contained Terpene, Oxygenated monoterpene,, Hydrocarbon monoterpene,
Oxygenated sesquiterpene and Hydrocarbon sesquiterpene ranging from 86.67-87.01%, 8.01-
8.32%, 1.57-1.97%, and 1.04 -2.64%, respectively. The extracted essential oils were also
evaluated for their antibacterial activities by papering disc diffusion method against four
bacterial species of Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas
aeruginosa, and Proteus mirabilis. EPEO extracts of the plant were shown to have higher
antibacterial activities with maximum zone of inhibition (14.43±0.15mm) against S. aureus
and minimum zone of inhibition (7.77±029 mm) against P. aeruginosa than HUEO extract
with the maximum zone of inhibition (14.23±0.11mm) against S.aurous while minimum zone
of inhibition (6.47±0.21 mm) against P. aeruginosa compared with that of Streptomycin
against bacteria as references antibiotics
