Radicales libres y sistema antioxidante

Free radicals are compounds characterized by having an unpaired electron in their outer orbit, a condition that makes them highly reactive, i.e., they interact through diffusion-controlled reactions with proteins, lipids and nucleic acids. They have also been referred to as reactive oxygen species (ROS), reactive nitrogen species (RNS) or reactive sulfur species (RSS). In the human organism, they are mainly produced in the mitochondrial electron transport chain, where respiratory complexes I and III specifically participate and reduce oxygen by converting it into superoxide anion. Likewise, they can be formed through a wide variety of enzymatic and non-enzymatic reactions involving substances that are synthesized by cells or are ingested with food and some medicines. Human beings have an antioxidant system which is both enzymatic and non-enzymatic in nature and whose function is to protect the organism from the harmful action of free radicals. This system includes enzymes—such as catalase, superoxide dismutase, thioredoxin, etc.—and non-enzymatic compounds— such as glutathione, ferritin, myoglobin, etc. However, they are not efficient enough to protect it, so it is necessary to eat foods that contain substances with antioxidant properties whose protective action will depend on their chemical reactivity and their concentration. These antioxidant compounds are mainly found in fruits and vegetables, where polyphenols, flavonoids, carotenoids, vitamin C, vitamin E, etc. have been identified. A significant amount of evidence suggests that