The Antibacterial Activity of Leaf Extracts of Eucalyptus camaldulensis (Myrtaceae)

The antibacterial activity of the leaf extracts of Eucalyptus camaldulensis was studied against Klebsiella spp, Salmonella typhi, Yersinia enterocolitica, Pseudomonas aeruginosa (Gram-negative), Staphylococcus aureus and Bacillus subtilis by the agar diffusion method. The methanol extract, dichloromethane fraction and methanol residue at 10mg mL-1 displayed broad spectrum activity against all the test organisms but the petroleum ether fraction showed no activity. The antibacterial activity of the extracts was compared to the drug gentamycin. The minimum inhibitory concentrations of the methanol extract and dichloromethane fraction determined by the agar dilution method ranged between 0.04 and 10mg mL-1 with that of Bacillus subtilis being the least. Phytochemical screening of the plant revealed the presence of tannins, saponins and cardiac glycosides. The results of this study support the traditional use of Eucalyptus camaldulensis leaves as an antibacterial agent. Key words: Eucalyptus camaldulensis, antibacterial activity, minimum inhibitory concentration, methanol extract, dichloromethane fractio