Antibacterial Activity of Ocimum gratissimum L. against Some Selected Human Bacterial Pathogens

Abstract

Aim: This study was designed to investigate the bioactive spice to determine its activity against some selected human bacterial pathogens. The spice studied was Ocimum gratissimum (clove basil). Place and Duration of study: Microbiology laboratory of Bells University of Technology between October, 2016 to July, 2017. Methodology: The plant extracts was tested for their activity against Staphylococcus species, Escherichia coli, Enterococcus faecalis, Proteus mirabilis and Klebsiella pneumoniae collected from microorganism bank of Bells University of Technology. Antibacterial activity was carried out using agar diffusion method while agar dilution method was employed for determining the minimum inhibitory concentration (MIC) on Mueller-Hinton agar.   Results: The findings of this study showed that the spice contained phytochemicals which made it active against the tested microorganisms. Hot water extract was more active against all tested isolates with MIC of 5.0 mg/ml against Klebsiella pneumoniae to 10 mg/ml against Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Enterococcus faecalis. Zone of inhibition was between 18 mm for Staphylococcus aureus and Enterococcus faecalis and 31 mm for Proteus mirabilis. Conclusion: Ocimum gratissimum has a broad spectrum antibacterial activity against all tested isolates and thus has a potential as a source of natural drugs. However, in vivo studies are recommended.