Antimicrobial and Antioxidant Activities of the Stem Bark of Cussonia bancoensis

Abstract

Cussonia bancoensis is used in Ghana mainly for the management of pain and treating infectious diseases. This study investigated the antibacterial and antifungal effect of the methanol, ethyl acetate and petroleum ether extracts of the stem bark of C. bancoensis by the agar dilution method. The antioxidant activity of the methanol extract was also investigated by DPPH free radical scavenging assay, total antioxidant capacity and total phenol content determined. The methanol and ethyl acetate extracts inhibited growth of all tested microorganisms with the exception of Streptococcus pyogenes in the antimicrobial assay. The minimum inhibitory concentrations ranged from 625 µg mL-1 to 2500 µg mL-1 for susceptible organisms. The petroleum ether extract had no antimicrobial activity at the concentrations used. The methanol extract scavenged DPPH with an IC50 value of 2.890 µg mL-1 and a total antioxidant capacity of 110.6 ± 41.15 mg g-1 (ascorbic acid equivalent). The total phenolic content expressed as tannic acid equivalent was 43.40 ± 14.70 mg g-1. The results of this study justifies to some extent the use of C. bancoensis in the treatment of microbial infections and supports the ethnomedical evidence that the plant could be a potential source of natural antimicrobial and antioxidant agents.