Antibacterial activity of <i>Waltheria indica</i> Linn (Sterculiaceae), collected from Blouberg area, Limpopo Province, South Africa

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.

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

African Journal of Biotechnology, Vol 13(31), 3198-3203