Antibacterial activity of some powdered herbal preparations marketed in Kaduna metropolis

The aim of the study was to investigate the phytochemical components and the antibacterial activities of some powdered herbal medicinal preparations sourced from identified herbal shops and retail outlets in different parts of Kaduna metropolis. Extracts obtained from the herbal preparations were screened for the presence of secondary metabolites using established procedures. Also, antibacterial activities of the extracts were evaluated. Carbohydrates and tannins were identified in 105 (70%) and 101 (67.3%) of the samples respectively. Alkaloids were found in 97 (64.7%); saponins were detected in 91 (60.7%), while anthraquinones, flavonoids and cardiac glycosides were identified in 82 (54.7%), 80 (53.3%) and 60 (40%) of the herbal preparations respectively. All the methanolic extracts had inhibitory activities on the test bacterial isolates at various minimum inhibitory concentrations: 81 (54%) had inhibitory effects on Staphylococcus aureus, 74 (49.3%) on Escherichia coli, 74 (49.3%) on Salmonella typhi and 63 (42%) on Shigella spp. The uses of these products in herbal medicine are justified. However, further works are needed to identify the chemical nature of the active substances as well as their modes of actions on the bacterial cells and their roles in disease curing.