Vitamin E: protective role of a Janus molecule

摘要: Since the discovery of vitamin E in 1922, its deficiency has been associated with various disorders, particularly atherosclerosis, ischemic heart disease, and development different types cancer. A neurological syndrome resembling Friedreich ataxia also described. Whereas epidemiological studies have indicated role preventing progression atherosclerosis cancer, intervention trials produced contradictory results, indicating strong protection some cases no significant effect others. Although it is commonly believed that phenolic compounds like exert only a protective against free radical damage, antioxidant molecules can other biological functions. For instance, activity 17-beta-estradiol not related to determining secondary sexual characters, capacity all-trans-retinal distinguished from rhodopsin vision. Thus, unusual alpha-tocopherol (the most active form E) properties independent antioxidant/radical scavenging ability. The Roman god Janus, shown ancient coins as having two faces one body, inspired designation 'Janus molecules' for these substances. new biochemical face was first described 1991, an inhibitory on cell proliferation protein kinase C activity. After decade, this nonantioxidant well established, confirmed by authoritative signal transduction gene regulation. More recently, tocopherol binding possible receptor function discovered. Despite such important developments understanding molecular mechanism targets E, Janus fully elucidated. Greater knowledge events will help selecting parameters clinical population type, dose response effects, synergism compounds.