Abstract

Mature roots of Waltheria indica were collected from Blouberg area, Limpopo Province, republic of South Africa. Water, ethanol and methanol extracts were investigated for antibacterial activity at 5 mg/ml against 10 human pathogenic strains using disc diffusion method. Ethanol extract exhibited potent antibacterial activity against selected strains while methanol extract exhibited largest zone of inhibition of 15.2±2.18 mm against Bacillus pumilus. Extracts were further investigated for antibacterial activity using minimum inhibitory concentration (MIC) assay. Lowest MIC of 0.65 mg/ml was exhibited by methanol extract against Acinetobacter calcaoceuticals anitratus. Water extract exhibited good MIC of 2.08 mg/ml against Escherichia coli while ethanol extract showed lowest MIC of 1.04 mg/ml against Enterobacter cloacae and 6.25 mg/ml against Klebsiella spp., Serratia marscens and Staphylococcus epidirmidis. Moreover, ethanol extract possessed a total activity of 433 mL/g against Enterococcus faecalis, meaning that the extract can be diluted to 433 mL and would still inhibit growth of these bacteria. These results in a way validate the use of W. indica L in the treatment of variety of infections, especially urinary tract infecting bacterial strains.

Key words: Waltheria indica L, minimum inhibitory concentration (MIC), disc diffusion, total activity, antibacterial.