Chemical constituents,physicochemical properties and antibacterial activity of leaves essential oil of Ocimum urticifolium

Objective:To determine chemical compositions,physicochemical properties and evaluating antibacterial activities of essential oils extracted from leaves of Ocimum urticifolium(O.urticifolium).Methods:Essential oil of O.urticifolium was extracted by hydrodistillation technique.A number of phytochemical screening tests were applied to identify the classes of compounds in the leaves extract of O.urticifolium.Gas chromatography and gas chromatography/mass spectrometry were used to characterize the chemical components in the essential oil.The agar diffusion method was used to evaluate the antibacterial activity as per of standard procedure.Results:Phytochemical screening of crude extract revealed that the presence of tannins,glycosides,saponins,flavonoids,steroids,terpenoids and phenols.The obtained oil yield is(0.33±0.11)%(v/w).Analysis of oil using gas chromatography and gas chromatography/mass spectrometry showed a total of 22 components,the abundance of monoterpene and sesquiterpenes(98.99%).The percentage composition of monoterpene in the oil wasα-pinene(22.105%),eugenol(21.099%),while sesquiterpenesα-cubebene(11.341%),α-bisabolene(9.945%),α-caryophyllene(7.709%),α-caryophyllene oxide(5.754%),and copaene(3.594%).The oil inhibited the growth of Staphylococcus aureus and Escherichia coli,while no activity was shown to Salmonella typhi.Conclusions:The O.urticifolium is a rich source of various classes of chemical constituents and the antibacterial activity of the oil could be attributed mainly to these compounds.