Carissa edulis and Caesalpinia volkensii have been used through ages by herbalists in many parts of the world to treat various ailments. Although these medicinal plants have been widely used traditionally in treating diseases associated with oxidative stress, there is limited literature to validate their use. This study therefore, sought to determine the ethnobotanical efficacy of the plants as alternatives in the management of free radical- causing diseases using different in vitro assay systems. Qualitative phytochemical analysis was also done to check the presence of phytoconstituents. Generally, the extracts exhibited good antioxidant activity as compared with the standard (Ascorbic acid). However, the root bark extracts of Carissa edulis showed better reducing power activity (0.88mg/mL), DPPH radical scavenging activity (82.13%) and hydrogen peroxide scavenging ability (84.31%) than the leaf extracts of Caesalpinia volkensii (0.83mg/mL, 75.8% and 74.49% respectively). In addition, Carissa edulis showed higher total phenolics and flavonoid contents than Caesalpinia volkensii. The phenol contents for the extracts were 146.5Â±3.28 mg /g and 126.0Â±1.50 mg/g respectively. On the other hand, the flavonoid contents were 91.33Â±3.51 mg/g and 46Â±3.0 mg/g respectively. Furthermore, the results obtained from both plant extracts were concentration dependent.
Keywords: Antioxidant, ascorbic acid, free radial, phenols, phytocostituents