RESUMEN
Aims: This study was design to screen the stem bark extract of Pseudocedrela kotschyi for the presence of phytochemical constituents and evaluate the extract for antimicrobial activity on wide range of pathogenic bacteria and fungi species. Place and Duration of Study: Department of Pharmaceutical and Medicinal Chemistry, Usmanu Danfodiyo University Sokoto and Laboratory of Pharmaceutical Microbiology, Ahmadu Bello University Zaria, between April 2013 and Oct 2013. Methodology: Plant material was extracted with methanol and phytochemical screening carried out. Sequentially, the methanol extract was partitioned against chloroform, ethyl acetate and n-butanol to afford chloroform, ethyl acetate and n-butanol soluble fractions respectively. All fractions were evaluated against panel of pathogenic bacteria and fungi to include Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus pyogenes, Corynebacterium ulcerans, Bacillus subtilis, Escherichia coli, Salmonella typhi, Shigella dysenteriae, Klebsiella pneumoniae, Neisseria gonorrhoeae, Pseudomonas aeruginosa, Candida albicans, Candida krusei and Candida tropicalis. Results: Phytochemical screening of the extracts revealed the presence of saponins, flavonoids, tannins, glycosides, anthraquinones, steroids/terpenes as well as alkaloids. The susceptibility test of the fractions at 30mg/ml have displayed activity against S. aureus, S. pyogenes, E. coli, S. dysenteriae, P. aeruginosa, C. albicans, C. krusei and C. tropicalis at zone of inhibition ranges between 20-28mm while the MIC and MBC/MFC results showed spectrum of antimicrobial activity ranges between 2.5-10mg/ml and 5-30 mg/ml respectively. Conclusion: The activity of the extracts against S. pyogenes, E. coli, S. dysenteriae, P. aeruginosa and C. albicans, justify the traditional use of stem bark of Pseudocedrela kotschyi in the treatment of diarrhoea, dysentery and oral infection which are diseases commonly caused by these organisms.