Effects of tannins and polyphenols of some medicinal plants on bacterial agents of urinary tract infections

Abstract

Five medicinal plants, Enantia chloranthia, Kigelia africana, Bridelia ferruginea, Trema nitems and Drypetes gossweilerri were screened for phytochemical components. The plants were found to contain tannins, phlobatannins, alkaloids, cardiac glycosides, anthranoids, anthraquinones, saponins and polyphenols. The crude aqueous and ethanolic extracts as well as tannins and polyphenols of the plants were tested on some bacterial agents of urinary tract infections (UTI). The results revealed that the extracts inhibited Staphylococcus aureus, Pseudomonas aerugosina, Klebsiella sp., Proteus sp. and Escherichia coli to varying degrees. However, the ethanolic extracts showed greater degree of inhibitory activity on the organisms than the aqueous extracts. Similarly, the tannins and polyphenols inhibited S. aureus, Klebsiella sp., Proteus sp. and E. coli but had no inhibitory effect on Pseudomonas aeruginosa. The minimal inhibitory concentration (MIC) values for the test bacteria varied but generally ranged between 3% and 7%. Mixing the ethanolic extracts of all five medicinal plants together resulted in lower MIC values for the organisms. The utilization of these plants for the manufacture of drugs for the treatment of UTI is highlighted.

Keywords: Tannins, polyphenols, bacteria, urinary tract infections


(Global Journal of Pure and Applied Sciences: 2003 9(2): 193-198)