Abubeker, Yimam (PhD)Seblewongel, Gashaw2021-03-302023-11-102021-03-302023-11-102021-03http://etd.aau.edu.et/handle/12345678/25791Essential oils are aromatic substances that found in the immune system of the plant and it is very interesting natural product in their variety application. Ethiopia has also spending a huge foreign currency to import the essential oil for its different application. This study has been carried out to extraction of essential oil from the leaves of Ocimum basilicum L. by using steam distillation extraction method. The Sweet basil (Ocimum basilicum L.) is a native plant in Ethiopia locally named as “Bessobela’’ (in Amharic). This study is more important in investigation of sweet basil as assume the one of the economy source crop for extraction of essential oil and decreasing a country foreign currency spending to import EO. A general factorial design was applied to in the analysis of results using DESIGN-EXPERT 6.08 software and linear regression model. In this study, the minimum and maximum oil yield are 0.12% and 0.8% respectively. Thus, minimum was obtained at 2hrs in the extraction of fresh sweet basil leaves and maximum oil yield of 0.8 % was obtained at a time of 4hrs in extraction of the sweet basil dried in atmospheric air. Characterization of the oil at the optimum condition yield was also carried out and also the results are shown as 0.8481��/����3 specific gravity, 1.49 refractive index value, 3.5 pH, 6.02 mpas dynamic viscosity, 205oC boiling point temperature, 78oC flash point, 5.04 mgKOH/g acid value, 56 mgKOH/g saponification value, 3.17 ml/g iodine value and 50.93 mgKOH/g ester value. The essential oil was analyzed by using GC-MS and FTIR. Then, Twenty-five components were obtained and it has been reached in monoterpene hydrocarbons, oxygenated monoterpenes, sesquitrpene and alcohol group. Generally , according to its chemical constituents , the sweet basil essential oil exhibits potent antimicrobial activity due to its richness in linalool (oxygenated monoterpene), and the Methyl chavicol (estragol) constituents of O. basilicum oil implies that EO extensively used as a flavoring, antimicrobial, antioxidant and anti-inflammatory agent.en-USEssential oilGC-MSFTIROcimum basilicum Lsteam distillationThesis