The Antimicrobial Activities of Root Extract of Buchholzia coriacea Engler (Wonderful Kola) against Gram-positive and Gram-negative Pathogens

Abstract

This study was conducted to investigate antimicrobial activity of aqueous and methanol root extract of Buchholzia coriacea against selected Gram positive and Gram-negative clinically significant bacteria as well as determine phytochemical constituent of the root of the plant. The extraction of the plant root parts was carried out using the Soxhlet extraction method and the antimicrobial screening of the root extract was performed using the agar diffusion technique. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration of root extract against test microorganisms such as (Staphylococcus aureus, Escherichia coli, Bacillus
subtilis, and Pseudomonas aeruginosa) and fungus (Aspergillus niger employing the seeded plate method. Tioconazole and Ciprofloxacin were used as positive controls. Phytochemical screening showed the presence of tannins saponins, terpenoids, and flavonoids while alkaloids and anthraquinones were absent in the dried root extract of Buchholzia coriacea. Antibacterial antifungal activities were observed. The IZD for methanol root range from 7 mm at 6.25 mg/m to 19 mm at 100 mg/ml for the bacterial isolates, while the IZDs for the A. niger range from 16 mm at 100 mg/ml and 6.25 mg/ml respectively. Meanwhile IZD of the aqueous extract range between 6 mm to 17 mm at 6.25 mg/ml and 100 mg/ml respectively for the bacterial isolates. The IZD of the A. niger range from 7 mm to 15 mm at 6.25 mg/ml and 100 mg/ml respectively. MIC of the methanol root extract of B. coriacea range between 25 mg/ml to 50 mg/ml for both bacteria and the fungus. The MIC of aqueous root extract was between 50 mg/ml to 100 mg/ml for the bacteria, while the MIC for A. niger was 50 mg/ ml for both methanol and aqueous root extracts. Buchholzia coriacea root bark can be formulated into suitable dosage forms and used for treatment of infections by susceptible organisms. The extract had activity against gram- positive and gram-negative organisms and showed some anti-fungal activity. The aqueous extract had higher MIC concentrations than the methanol root extract.