Antioxidants in the Prevention and Treatment of Cancer

Abstract

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are constantly produced in all aerobic organisms, mostly as a consequence of normal cellular aerobic respiration. Many factors outside the body, such as unhealthy diets and behaviours, exposure to environmental pollutants and radiation pollution, also trigger the production of abnormally high concentrations of highly reactive and toxic ROS and NOS in tissues and organs of biological systems. The excessive production of ROS/RNS causes damage to DNA, proteins and lipids and can increase the risk of cancer. Antioxidants maintain redox homeostasis and prevent ROS-/RNS-induced damages that have been associated with cancer development. In the body, antioxidant defence systems include endogenous (enzymatic and non-enzymatic antioxidants) and exogenous antioxidants supplied by plant foods. Plants or parts of plants with