Experiments of Antioxidant Activities

Antioxidants decrease reactive species such as hydrogen peroxide (H2O2), hypochlorous acid (HClO), hydroxyl radical (·OH), superoxide anion radical (O2−), nitric oxide radical (NO·) and lipid peroxyl radical (LOO·) that cause damage to cellular components such as DNA, proteins, carbohydrates and lipids. Endogenous enzymatic (synthetic/physiological) antioxidants like phytochemicals, vitamins and exogenous non-enzymatic (natural) antioxidants like superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR), peroxiredoxin I–IV and catalases (CAT) play a vital role in human health system and as preservatives, pharmaceuticals and food materials. However, the mode of action of the exogenous and endogenous antioxidant molecules is concentrated on their biosynthetic origin, structural features and functional groups. This chapter deals about the procedures of assessing antioxidant activity in vitro by free radical scavenging (DPPH and NO) and ferric reducing antioxidant power assays (FRAP) as well as in vivo via monitoring SOD and CAT activities and GSH and MDA levels.