Antibacterial, anti-inflammatory and mutagenic effects of some medicinal plants used in South Africa for the treatment of wounds and retained placenta in livestock

Crude dichloromethane and 90% methanolic extracts of plants used traditionally in the treatment of wounds and retained placenta were screened for their antibacterial, anti-inflammatory (cyclooxygenase-1 and-2) activities and investigated for potential mutagenic effects. Antibacterial activity was evaluated using the micro-dilution assay. The bacterial strains used were Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). DCM extracts of Dicerocaryum eriocarpum, Pterocarpus angolensis, Ricinus communis and Schkuhria pinnata exhibited the highest antibacterial activity. In the anti-inflammatory assay, dichloromethane extracts of stems of Cissus quadrangularis and roots of Jatropha zeyheri showed selective inhibition of COX-2 (75% and 77%), while dichloromethane extracts of the shoots of S. pinnata showed selective inhibition of COX-1. None of the plant extracts were mutagenic in the Salmonella typhimurium Ames test (strain TA98). The results suggest that most plants used traditionally for treating wounds and retained placenta in animals are effective in combating infection and reduction of pain. Lack of mutagenicity suggests that these plants are probably safe for use.