Antibacterial, anthelmintic and anti-amoebic activity in South African medicinal plants

Hexane, ethanol and water extracts of plants used by South African traditio nal healers for treating stomach ailments were screened for antibacterial a nthelmintic and anti-amoebic activities. To evaluate antibacterial activity , the disc-diffusion assay was used against several Gram-positive and Gram- negative species. Minimal inhibitory concentration values were determined w ith a microdilution assay. Ethanolic extracts showed the greatest activity, and Gram-positive bacteria were the most susceptible microorganisms. The f ree-living nematode Caenorhabditis elegans was used in two different assays to evaluate anthelmintic activity. A microdilution technique was employed to investigate anti-amoebic activity against the enteropathogenic Entamoeba histolytica. These assays were suitable for the screening of a large numbe r of extracts at one time. Several plants exhibited significant activity ag ainst these test organisms. (C) 2000 Elsevier Science Ireland Ltd. Al right s reserved.