Tocopherols, tocotrienols, and their bioactive analogs

Vitamin E is a lipid-soluble vitamin naturally synthesized by photosynthetic organisms (Yerin et al., 1984). The term “vitamin E” refers to a group of chemical compounds, tocols, and tocotrienols that act as antioxidant compounds and maintain the stability of cell membranes against oxidative stress. The antioxidant activity of vitamin E seems to be correlated with their capacity to quench free radicals and, in particular, reactive oxygen species produced by the cell metabolism. Vitamin E was discovered by Evans and Bishop (1922) and called “substance X” because it was essential to maintain rat fertility. The most active vitamer of vitamin E is α-tocopherol (from the Greek tokos = child, phero = to bear, and -ol indicating that the substance is an alcohol), isolated for the ‚rst time from wheat germ oil (Evans et al., 1936). © 2012 by Taylor & Francis Group, LLC