Antimicrobial Effects of the Stem Bark Extracts of Parkia biglobosa (Jacq.) G. Don on Escherichia coli and Staphylococcus aureus

Aims: This work aimed to evaluate the antimicrobial potential of the stem bark extracts of               P. biglobosa on selected bacteria species, Escherichia coli, and Staphylococcus aureus. 
Place and Duration of Study: Microbiology laboratory, Department of Biological Sciences, Bingham University-Karu, Nasarawa State, Nigeria. 
Methodology: Plant extracts were made by boiling, soaking and methanol extraction, and the antimicrobial assay was performed using the disc and agar-well diffusion methods. 
Results: The results indicated all the extract exhibited antimicrobial properties. The highest potential activity was observed with the macerated extract with zones of inhibition at 12.5 mm and 6.5 mm against S. aureus and E. coli, respectively in the agar-well diffusion method while no active zone of inhibition was recorded in the disk diffusion method. It was noted that the macerated extract showed the highest MIC of 100 mg/ml with a zone of inhibition at 15.0 mm against S. aureus.  
Conclusion: The results obtained showed that the macerated extract of the plant possess the highest antimicrobial effect against S. aureus, and E. coli. Although observed potency of this extract in vitro, may not be translated to the same activity in vivo. However, the results confirmed the efficacy of the plant as a natural antimicrobial and can be further investigated for possible antimicrobial drug discovery.