ABSTRACT Plants are sources of natural antioxidants and some of their compounds have significant antioxidant properties and health benefits. Olaxsubscorpioidea and Distemonanthusbenthamianus are used in folk medicine for the treatment of many diseases. This study was undertaken to evaluate the in vitro antioxidant potential and the phenolic contents of the aqueous and 70% ethanolic extracts of the leaves of these plants. The antioxidant activity and phenolic contents of the aqueous and 70 %ethanolic extracts of the leaves of O.subscorpioidea and D.benthamianus were evaluated using Spectrophotometric methods for the determination of total phenols, total flavonoids, flavonols and proanthocyanidins. The antioxidant activity of the extracts was determined by the 1,1-Diphenyl-2-picrylhydrazyl, anti-lipid peroxidation, reducing power and ferrous chelating ability methods. The ethanolicextracts had the highest antioxidant activitiesand phenolic compoundslevels.D.benthamianusexhibited strong DPPH scavenging activity (IC 50 =10.87 ± 0.18),lipid peroxidation inhibition assay (IC 50 =0.97 ± 0.01 mg/mL),ferrous chelating assay (IC 50 =0.94 ± 0.02 mg/mL) added to its higher reducing power andphenolic contents (102.8±0.57 mg/g extract). Theantioxidant propertiesof these plants may explain their therapeutic activities. Our following work will explore the pharmacological potential of D. benthamianusethanolic extract
