Abstract

Free radicals are produced by a variety of normal biological processes including aerobic metabolism and pathogenic defense mechanisms. They can also be a result of external exposures such as radiation, pollutants, and cigarette smoke. Reactive oxygen species, or ROS, are a subset of free radicals that contain oxygen. A diet high in antioxidants may reduce the risk of many diseases (including heart disease and certain cancers). Antioxidants scavenge free radicals from the body cells and prevent or reduce the damage caused by oxidation. The protective effect of antioxidants continues to be studied around the world. During aerobic metabolism, oxidants, or reactive oxygen species, are created in our bodies, which can cause a number of illnesses, including cancer and cardiovascular conditions. The substances that balance these oxidants called antioxidants. Natural antioxidants are recommended over synthetic antioxidants, which have been discovered to have adverse effects. Natural antioxidants are the secondary metabolites of phytochemicals. The impact of oxidants on human health and how natural antioxidants counteract them have both been reviewed. The main plant sources of natural antioxidants, several methods for recovering antioxidants from plant matrices, and the superiority of indirect supercritical fluid extraction over other methods are all discussed. 

Keywords

oxidative stress, secondary metabolites, recovery processes, and process factors