Free Radicals and the Role of Plant Phytochemicals as Antioxidants Against Oxidative Stress-Related Diseases

Free radicals or reactive oxygen species (ROS) generated from various sources in the environment as well as from cellular processes in the body are of serious health challenges. Overwhelming levels of these free radicals disrupt the antioxidant defense system in the body thereby damaging cell membranes and cellular macromolecules such as proteins, lipids and nucleic acids leading to cell death or causing mutations leading to uncontrolled cell division. Once the cellular antioxidant system is disrupted and becomes deficient, oxidative stress emerges thereby promoting several diseases such as diabetes, arthrosclerosis, cancer, cardiovascular diseases, etc. Better management of oxidative stress requires antioxidants from external sources to supplement the body’s antioxidant defense system. Because of their natural origin and therapeutic benefits, plants have been considered as a major source of antioxidants. Certain non-enzymatic plant phytochemicals such as glutathione, polyphenols, bioflavonoids, carotenoids, hydroxycinnamates as well as some vitamins have shown to possess antioxidant properties in vitro and in vivo. These plant phytochemicals are now been used in the prevention and management of oxidative stress-related diseases.