Evaluation of the in vitro antioxidant and iron chelating activity of Gymnema sylvestre

The study evaluated the in vitro antioxidant activity of 70% methanolic extract of Gymnema sylvestre leaves, which is was well known for its antidiabetic and sweet suppressing properties. The extract was used to determine the antioxidant potential using different tests including total antioxidant activity; efficiencies for scavenging of hydroxyl, superoxide, nitric oxide, singlet oxygen radicals and hypochlorous acid. Iron chelating, inhibition of lipid peroxidation and DNA protective properties were measured along with total phenolic and flavonoid content determination. The extract was found to be an antioxidant with a TEAC value 0.386 ± 0.19. The extract had shown its scavenging activity for different radical and 184.96 ± 2.44 μ g/ml, 15.56 ± 0.8 μ g/ml, 65.35 ± 2.56 μ g/ml, 1.89 ± 0.084 mg/ml and 143.09 ± 55.49 μ g/ml were determined as IC50 values for hydroxyl, superoxide, nitric oxide, hypochlorous acid radicals and lipid peroxidation inhibition, respectively. It was also observed that the plant extract (100 mg) has 23.7 ± 0.006 mg/ml gallic acid equivalent phenolic and 81.73 ± 0.008 mg/ml quercetin equivalent flavonoid content. The present results provide evidence that 70% methanol extract of Gymnema sylvestre leaves acts as an antioxidant and free radical.