Antibacterial effect of Chromolaena odorata leaf extracts on selected bacterial isolates

Abstract

This study was done to assess the antibacterial effect of aqueous and ethanolic extracts of Chromolaena odorata against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Sensitivity plates were prepared using Mueller-Hinton agar, test organisms were inoculated unto the plates, and discs impregnated with C. odorata extracts were aseptically placed on the plates which were then incubated at 37 ℃ for 24 hours. The three microorganisms showed susceptibility to both aqueous and ethanolic extracts of Chromolaena odorata. Zones of inhibition ranging from 2.00 mm to 12.20 mm and 3.20 mm to 18.40 mm were produced by the different concentrations of the aqueous and ethanolic extracts respectively. There was no statistical difference (p > 0.05) between the mean zones of inhibition produced by both aqueous and ethanolic extracts. The Minimum inhibitory concentration (MIC) of the aqueous extract for S. aureus and K. pneumoniae was 12.5 mg/mL while E. coli was 25 mg/mL. S. aureus and E. coli had MIC of 6.25 mg/mL, while K. pneumoniae had MIC of 12.5 mg/mL for the ethanolic extract. S. aureus and K. pneumoniae had 25 mg/mL while E. coli had 50 mg/mL as Minimum bactericidal concentration (MBC) of aqueous extract. For the ethanolic extract, S. aureus and K. pneumoniae had MBC of 12.5 mg/mL and E. coli had an MBC of 25 mg/mL. The data obtained from the study indicates antibacterial properties of extracts of C. odorata, thus encouraging its usage for the production of novel antibiotics.