Vol. 3, Issue 5 (2019)
Physicochemical Properties and Antimicrobial activities of Essential oil extracted from Eucalyptus globulus leaves
Author(s): Edah Alexander O, Ede Richard R, Stanley Victor F, Samuel John O
Abstract: Medicinal plants can serve as useful alternatives in antimicrobial therapy as well as sources of template molecules in new drug discovery. In this study, physicochemical properties and antimicrobial activity of Eucalyptus globulus leave oil were investigated to determine its efficacy against some bacterial pathogens. The leaves of the plant were collected, dried, pulverized and steam distillation was used to extract the oil. The results obtained were moisture content (1.4500 ± 0.1259%); ash content (3.7800 ± 0.3528%); % oil yield (3.1%); saponification value (266.4750mgKOH/g); iodine value (79.693gI2/100g); acid value (1.2679mgKOH/g); free fatty acid value (0.6378%); specific gravity (0.7663g/ml); pH (4.4500); refractive index (1.4626); colour (Pale yellow); odour (mint); Solubility (insoluble in aqueous and soluble in organic solvents) respectively. The Minimum inhibitory concentration and minimum bactericidal concentration of the extract was obtained using the agar disc diffusion method and dilution broth method. The result of the sensitivity test revealed that the extract of the leaves demonstrated efficacy against Escherichia coli and Staphylococcus aureus. The MIC Indicates that S. aureus and E. coli were susceptible to the leave extract at low concentrations ranging 75mg/ml to 300mg/ml, while the MBC value was 300mg/ml for both pathogens. Thus, the antibacterial activity of the extract could probably be due to the bioactive metabolites such as 1, 8-cineole (Eucalyptol), o-cymene, α-pinene, γ-terpinene and α-terpineol. Hence, could be used as an alternative and complementary medicine in the treatment of ailments caused by these organisms.