Browsing by Subject "MIC"

African medicinal plants have been used to treat symptoms of infection successfully for thousands of years. However, no antimicrobial drugs have been developed from these plants. As antibiotic resistance is increasing rapidly, these traditional African herbal medicines can be an important solution in the fight against antibiotic resistance due to their antimicrobial properties. In this research, various extracts o the leaves of Combretum adenogonium (Combretaceae) and the fruits of Piper cubeba (Piperaceae) and Xylopia aethiopica (Annonaceae) were tested for their growth inhibitory effects against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Extracts were made with methanol, water, hexane, and chloroform. In addition, water and ethyl acetate extracts were separated from an 80 % methanol extract using solvent partition. All the studied plants are used for the treatment of infections and wounds in African traditional medicine. Water was used as extraction solvent since it is commonly used in African folk medicine. Both single solvent technique and sequential extraction were used. The antibacterial effects were screened using agar diffusion and microdilution methods. The interaction between an extract and an antibiotic was measured with a checkerboard method. Time-kill experiments were performed using microdilution and plate count methods. In this study, the chloroform extract of C. adenogonium leaves gave the best inhibitory effect of all studied plants against B. cereus (MIC 78.125 µg/ml). In general, B. cereus was the most susceptible of the selected bacteria against extracts and E. coli was the one with most resistance. Time-kill test showed that the antibacterial efficacy was fairly stable throughout the 24-hour period considered with few exceptions. According to checkerboard results, C. adenogonium chloroform extract and tetracycline appeared to inhibit each other's antibacterial activity against B. cereus. However, only one extract was studied in this study, and it is possible that C. adenogonium contains compounds that would have a potentiating effect on antimicrobials. In general, C. adenogonium extracts were effective against B. cereus. The extracts of P. Cubeba were particularly effective against S. aureus. X aethiopica extracts were equally effective for both B. cereus and S. aureus. Methanol extract X. aethiopica is the only extract studied that gave more than 90% inhibition against P. aeruginosa. Therefore, it could be concluded that X. aethiopica has the broadest activity range of the examined plants.