The role of glutathione in the gastrointestinal tract: a review
The primary role of glutathione is to protect cells from oxidative stress. It is abundantly distributed in the mucosal cells of gastrointestinal tract both in animals and man. The highest concentration is found in the duodenum. The amount of glutathione ingested with foods, age and drug or ethanol consumption affect glutathione concentration. The detoxifying capability of glutathione is directly related to its thiol group and to its function as a substrate for enzymatic activity; in fact, glutathione regulates the action of glutathione-peroxidases and glutathione-transferases. It has been documented that a direct relation between glutathione concentration and mucosal damage or between glutathione-related enzymes and cancer occurrence is present in various pathological conditions of the gastrointestinal tract (from oesophagus to rectum). The present review underlines: a) the role of oxidative stress in numerous physiological and pathological conditions in experimental animals and man; b) the need to maintain a normal antioxidant potential in the mucosal cells of the gastrointestinal tract; and c) the possibility to evaluate, through clinical studies, how glutathione concentration, food intake, and gastrointestinal diseases are associated.