Evaluation of Three Medicinal Plants of Bangladesh for Antimicrobial Properties

Aim: The methanolic crude extracts of Wedelia chinensis Osbeck. Merr. whole plant, Mimosa diplotricha Sauvalle. stem bark and Bauhinia purpurea Roxb. leaf as well as their organic and aqueous soluble partitionates were evaluated for antimicrobial potential.

Study Design: Evaluation of antimicrobial activity by disc diffusion method.

Place and Duration of Study: Phytochemical Research Laboratory, Department of Pharmacy, School of Health Science, State University of Bangladesh, from April to September, 2016.

Methodology: Accurate amount of test sample was weighed and dissolved in measured volume of solvent which was then applied to sterile discs. The discs were then carefully dried for the evaporation of the residual solvent. The Institute of Nutrition and Food Science (INFS) of University of Dhaka provided the bacterial and fungal strains used for the experiment. The strains were collected as pure cultures. In this investigation, ciprofloxacin (30 μg/disc) disc was used as the standard.

Results: The highest 16.0 mm zone of inhibition was exhibited against Vibrio parahemolyticus by the carbon tetrachloride soluble fraction of methanolic crude extract of W. chinensis. The hexane soluble fraction showed 12.0 mm zone of inhibition against Staphylococcus aureus. The carbon tetrachloride soluble fraction of M. diplotricha exhibited the highest 14.0 mm zone of inhibition against Pseudomonas aeruginosa. This fraction also revealed 11.0 mm zone of inhibition against. Bacillus megaterium. 5.0 to 15.0 mm zone of inhibition was demonstrated by test samples of B. malabarica. The carbon tetrachloride soluble fraction of B. malabarica extract showed the highest (15.0 mm) zone of inhibition against Salmonella typhi.

Conclusion: From our investigation, it can be suggested that, the extractives can further be studied extensively to find out their efficacy.