Abstract

The stem bark of Croton zambesicus was extracted using soxlet apparatus with petroleum ether, ethyl acetate, methanol and distilled water respectively. The extracts were screened for chemical components. The results revealed the presence of carbohydrates, saponins, cardiac glycosides, flavonoides, terpenes/steroids and alkaloids. In vitro antimicrobial study of the extracts revealed strong broad spectrum activity, especially for methanol extract. This is evident from the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) test results in which the methanol extract had MIC and MBC of 1.560 mg on Staphylococcus aureus and Escherichia coli, followed by ethyl acetate extract with MIC value of 3.125 mg and 6.25 mg for MBC on Pseudomonas aeruginosa. Petroleum ether extract showed the highest activity on Shigella dysenteriae, S. aureus and E. coli with MIC value 25 mg and 50 mg for MBC while the aqueous extract did not show activity at all. The result of this study provide more basis and credence for the use of this plant in the treatment of ailments whose causative agents are some of the pathogenic microbes used in this study, and thus suggest the possible usefulness of C. zambesicus in the treatment of bacterial and fungal infections.

Key words: Croton zambesicus, chemical constituents, antimicrobial, efficacies, extracts.