Abstract:
The antibacterial activities of ethanol, cold water, hot water and hexane extracts of
leaf of Calotropis procera was tested against vancomycin and methicillin resistant bacteria
isolated from wound patients in Ondo State Specialist Hospital Akure, Ondo State. The
bacteria isolates are: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa,
Klebsiella pneumoniae, Proteus mirabilis and Streptococcus pyogenes. They were exposed to
vancomycin and methicillin resistance test using disc diffusion method. The resistant bacterial
isolates were subjected to plasmid profiling using 0.8% agarose gel electrophoresis which
confirmed the basis of their resistance either plasmid or chromosomal mediated. Agar well
diffusion method was used to determine the antibacterial activities of the extracts on resistant
bacterial isolates. Ethanol extract had the highest zone of inhibition against Staphylococcus
aureus and Escherichia coli with 16.03mm and 12.05mm respectively while cold and Hot
water extracts recorded the least zones of inhibition values of 3.54mm and 5.53mm
respectively against Klebsiella pnuemoniae and Pseudomonas aeruginosa. However, the
n-Hexane extract had no inhibitory effect against Streptococcus pyogenes and Proteus
mirabilis. Minimum inhibitory concentration of the extracts was determined using tube
dilution method with values ranging between 15.625 and 125 mg/ml. Purification of the
extracts was carried out using column chromatographic techniques, and the antibacterial
potency of the purified fractions was investigated against the resistant bacterial isolates.
Phytochemical analysis of the extracts revealed the presence of alkaloids, flavonoids, tannin,
saponin, terpenoids, cardic glycoside and phenols. The Fourier Transform Infrared (FT-IR)
spectroscopic analysis of the active fractions showed five important functional groups
namely; phenols, hydroxyl, carbon-hydrogen, carbonyl and aromatic. Findings from this
research indicate that the leaf extracts of Calotropis procera posses antibacterial potency
which will assist in the preliminary treatment of wound infections, most especially because of
its high inhibitory effect against Staphylococcus aureus.
