Antioxidant activity of selected plants of the Great Fish River Reserve, Eastern Cape, South Africa

The Great Fish River Reserve (GFRR), in the Eastern Cape, has proved to be particularly suitable for the black rhinoceros that have been introduced over the past 20 years. In captivity, these animals often suffer from a number of disease conditions, certain of which may be related to antioxidant deficiencies in their diet. Therefore, the antioxidant capacities of the leaves of 25 bush species in the GFRR was determined by the DPPH, ABTS and FRAP methods and the total phenolics by the Folin-Ciocalteau procedure. The plant species Ozoroa mucronata, Putterlickia pyracantha, Phyllanthus verrucosus, Maytenus capitata, Euclea undulata and Jatropha capensis were found to have the highest antioxidant capacity by the three methods, whereas for total phenols Putterlickia pyracantha was replaced in the top six by Carissa bispinosa. The black rhinoceros in this area appear to favour plants of varying antioxidant capacity and do not seem to select browse species for this property.