Antioxidant Activity of Methanolic Extracts of Leaves and Flowers of Nerium Indicum

The Methanolic extract of leaves (LE) and Methanolic extract of flowers (FE) of Nerium indicum (Arali) was analysed for Antioxidant activity (AOA) in terms of DPPH free radicals, Total Phenolic Content (TPC) was measured in terms of Gallic acid equivalent and Flavonoid content was analysed in terms of Quercetin equivalent. The antioxidant activities of (LE & FE) were found to be 72.8% and 67 %. TPC of study extracts (LE & FE) were found to be 227 mg/100g and 449 mg/100g. The Total Flavonoid content of (LE & FE) were found to be 125 mg/100g and 199 mg/100g respectively. Superoxide anion radical scavenging activity of flowers was 66 % compared to leaves 25 %. Similarly Lipid Peroxidation showed higher activity in flowers than leaves. Enzymatic antioxidant activity such as Superoxide Dismutase, Glutathione peroxidase and Catalase of Nerium indicum flowers were around 10% to 30% higher than that of leaves. The results clearly indicate that the methanol extracts of Nerium indicum flowers have more potent antioxidant activity than leaves. INTRODUCTION: Oxidative stress depicts the existence of products called free radicals and reactive oxygen species (ROS), which are formed under normal physiological conditions but becomes deleterious when not being eliminated by the endogenous systems, In fact, oxidative stress results from an imbalance between the generation of reactive oxygen species and endogenous antioxidant systems. ROS are major sources of primary catalysts that initiate oxidation in vivo and in vitro and create oxidative stress which results in numerous diseases and disorders 1, 2 such as cancer , cardiovascular disease . Oxygen derived free radicals such as superoxide anions, hydroxyl radicals and hydrogen peroxide are cytotoxic and give rise to tissue injuries . Excessive amount of ROS is harmful because they initiate bio molecular oxidation which leads to cell death and creates oxidative stress causes inadvertent enzyme activation and oxidative damage to cellular system . Cells are equipped with different kinds of mechanisms to fight against ROS and to maintain the redox homeostasis of cell. For example, antioxidant enzymes such as superoxide dismutase (SOD) catalase (CAT) and glutathione peroxidase (GPx) play important roles in scavenging the free radicals and preventing cell injury . Molecules such as vitamin C and E inhibit lipid peroxidation in cell. When the mechanism of antioxidant protection becomes unbalanced in human body, antioxidant supplement may be used to help reduce oxidative damage. Medicinal plants are important source of antioxidants . Natural antioxidants increase the antioxidant capacity of the plasma and reduce the risk to certain diseases such as cancer, heart diseases and stroke . The secondary metabolites like phenolics and