Abstract

This study determined the potential antidiarrhoeal potential of Pericopsis angolensis and Swartzia madagascariensis extracts against Escherichia coli O157, Shigella species and Salmonella Typhi. Extracts were obtained using the following methods: (i) hot water extraction (90°C) (LHWE), (ii) cold water extraction (CWED) and (iii) ethanolic extraction (EED). Antimicrobial effects of the extracts were determined using the well diffusion assay. Phytochemical analysis was performed using standard biochemical methods. The LHWE extracts exhibited significantly greater inhibition than CWED and EED extracts as follows: (i) P. angolensis bark extract at 0.8 mg/ml against Shigella spp. and (ii) P. angolensis bark extract at 1.6 mg/ml and S. madagascariensis bark extract at 1.6 mg/ml against S. Typhi. The aqueous methods largely resulted in P. angolensis and S. madagascariensis extracts rich in flavonoids, saponins and tannins. The aqueous extraction methods (CWED and LHWE) are therefore suitable to obtain extracts with high antimicrobial effects against E. coli O157, Shigella species and S. Typhi.

Key words: Antidiarrhoeal, phytochemicals, extraction, Pericopsis angolensis, Swartzia madagascariensis.