Extraction and Antibacterial Activity of Essential Oils from Eucalyptus globulus

Abstract

The essential oil of Eucalyptus globulus obtained by hydrodistillation (Fever tree) was investigated for activity against two bacteria (Staphylococcus aureus and Klebsiella pneumoniae). The oil was extracted using a Clevenger-type apparatus. Separation, identification and determination of percentage composition of compounds present in the oil were carried out by Gas Chromatography Mass Spectrometry. The antibacterial activity was investigated by agar diffusion technique using various concentrations of the essential oil: 100% v/v, 75% v/v, 50% v/v, 25% v/v, 15% v/v. Minimum inhibitory concentration was determined using turbidimetric assay by taking the absorbance with the aid of a spectrophotometer. Minimum bactericidal concentration was by plate assay. Gas Chromatography Mass Spectrometry revealed the presence of seven compounds, all amounting to 90.4% with globulol having the highest percentage composition of 30.1%. The evaluation of sensitivity of the oil revealed the highest activity at 100% v/v against both isolates. Minimum inhibitory concentration was obtained at 25% v/v when assayed against K. pneumoniae with no activity at all against S. aureus at the same concentration. Oil showed no bactericidal activity at all concentrations, suggesting only bacteristatic activity of the oil. Investigation from this work revealed that the essential oil of E. globulus exhibit activity against the tested isolates and can thus be employed in the treatment of infections caused by them.