In the present study, we carried out a systematic research on relative antioxidant activity of aqueous leaf
extract of Stevia rebaudiana. The DPPH activity of aqueous leaf extract (20, 40, 50, 100 and 200 g/ml)
was increased in a dose dependent manner, which was found in the range of 40.00–72.37% as compared
to ascorbic acid 64.26–82.58%. The IC50 values of aqueous extract and ascorbic acid in DPPH radical scavenging
assay were obtained to be 83.45 and 26.75 g/ml, respectively. Measurement of total phenolic
content of the aqueous leaf extract of S. rebaudiana was achieved using Folin-Ciocalteau reagent containing
56.73 mg/g of phenolic content, which was found significantly potent when compared to reference
standard gallic acid. The aqueous extract also inhibited the hydroxyl radical, nitric oxide and superoxide
anions with IC50 values of 100.86, 98.73 and 100.86 g/ml, respectively. The greater amount of phenolic
compounds leads to more potent radical scavenging effects as shown by the aqueous leaf extract of S.
rebaudiana.