Parinari curatellifolia Planch ex Benth (Chrysobalanaceae) is used in traditional medicine for the treatment of pneumonia, wound infections, dressing of fractures and dislocation. P. curatellifolia stem bark extracts in methanol, ethylacetate and n-butanol were evaluated for antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis using cup plate method. The extracts were used at 50mg/ml concentration. The extracts were also screened for the presence of some secondary metabolites. The result of the antibacterial screening produced zones of inhibition ranging from 12-21mm for the methanolic extract while the ethylacetate and n-butanol fractions showed inhibition zones of 16-24mm respectively. The aqueous extract showed inhibition zones ranging from 12-20mm. Ampicillin (0.01mg/ml) used as positive control, showed zones of inhibition ranging from 14-34mm. Ethylacetate fraction was the most active of the extracts on the test bacterial species. Water was used as negative control. The extracts in most cases compared favorably with the ampicillin. The activity of the extracts was more on the gram positive bacteria than on the gram negative ones. The minimum inhibitory concentrations (MICs) of the ethylacetate fraction for B. subtilis, P. aeruginosa were 1.56mg/ml each, for E.coli and S. aureus were 3.13 mg/ml and 0.78mg/ml respectively. The minimum bactericidal concentrations (MBCs) of the ethylacetate fraction for B.subtilis and S. aureus were 6.25mg/ml each, for P. aeruginosa and E.coli were 12.50mg/ml each. The phytochemical screening revealed the presence of anthraquinones, tannins, saponins, flavonoids, cardiacglycosides, terpenoids, and carbohydrates. The antibacterial activity of the extracts may be attributable to the presence of these compounds in the extracts. The findings of this work lend support to the ethnomedical use of the plant.
Key words: Antibacterial; Phytochemistry; MIC; MBC; Parinari curatellifolia
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