Antibacterial and antioxidant activities of some selected plants used for the treatment of cattle wounds in the Eastern Cape

Abstract

This study was carried out to determine the antimicrobial and antioxidant properties of selected medicinal plants (Aloe ferox Mill, Ptaeroxylon obliquum (Thunb) Radlk. and Calpurnia aurea (Aiton) Benth) used for the treatment of cattle wounds. DPPH 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) and 2,2-azinobis (3-ethylbenzothiazoline-6-sulphuric acid) diammonium salt (ABTS), radical scavenging assays were used to determine the antioxidant activity of selected plants. Microbial susceptibility assay using the minimum inhibitory concentration (MIC) was used to test plant extracts against gram-negative and gram-positive bacterial strains. Each extract was also assayed to determine the total phenol, flavonoid, flavonol and prothocyanidin contents. The methanol extracts produced better results in all the assays. All plant extracts inhibited both gram-positive and gram-negative bacteria but there was more inhibition on gram-positive strains. Plant extracts tested also showed considerable scavenging activities against both DPPH and ABTS radicals at 0.2 mg/ml. These results are probably due to the level of phenols, flavonoids and flavonols in the extracts. The antibacterial and antioxidant activities displayed by these plants might justify their traditional use in wound healing and out of the three species tested, P. obliquum displayed the best antibacterial and antioxidant properties.

Key words: Antimicrobial, cattle, flavonoid, medicinal plants, phenol, scavenging activity, wound healing.