The measurement of the total antioxidant capacity of the plasma is used to assess the state of the body's antioxidant defense systems and the risk of developing diseases due to oxidative stress.
Reactive Oxygen Species (ROS) are produced as a result of normal aerobic metabolism. These free radicals are usually removed or converted to other products in vivo by a number of antioxidant systems. Antioxidants are usually chemically stable atoms and molecules that have one (or rarely more) free electrons in their outer electron layer. An antioxidant is a molecule capable of slowing down or inhibiting the oxidation of other molecules. Antioxidants protect cells from damage caused by the reactive oxygen species produced during oxidation reactions within the cell. Almost all biomolecules, but mainly biomembranes, proteins, and nucleic acids, can be affected by free reactive species. Free radicals are responsible for many pathological conditions or, they can be produced as a result of the pathological condition and may cause significant damage to biological systems and cells.
The link between free radicals and some serious diseases, including Parkinson's disease and Alzheimer's disease, atherosclerosis, myocardial infarction, and chronic fatigue syndrome, is now well established. However, short-term oxidative stress, which is the imbalance between the formation and removal of reactive oxygen species, can be important in the prevention of aging by activating a process known as hormesis. On average, 65-70% of the population is excessively affected by oxidative stress caused by reactive oxygen species.
The protective antioxidant system of organisms is based on the action of specific enzymes, in particular peroxide dismutase, glutathione peroxidase, catalase, glutathione reductase and non-enzymatic compounds with antioxidant activity, such as tocopherol, L-ascorbic acid (vitamin C), glutathione, coenzyme Q10, flavonoids, albumin, and other molecules. Excessive production of reactive oxygen species can lead to inflammation, premature aging, and various pathological conditions, including cancer, diabetes, and atherosclerosis. Organisms have developed complex antioxidant systems to protect against oxidative stress, however, excess ROS can overwhelm systems and cause serious oxidative damage.
The measurement of the total antioxidant capacity of the plasma (Total Antioxidant Capacity, TAC) assesses the functional state of all the antioxidant systems of the body, i.e., the total of enzymatic and non-enzymatic antioxidant compounds.