Which vitamin is also known as Alpha Tocopherol?
Alpha-Tocopherol Alpha-Tocopherol α-Tocopherol is a type of vitamin E. It has E number "E307". Vitamin E exists in eight different forms, four tocopherols and four tocotrienols. All feature a chromane ring, with a hydroxyl group that can donate a hydrogen atom to reduce free radicals and a hydrophobic side chain which allows for penetration into biological membranes. Compared to the others, α-tocopherol is preferentially absorbed and accumulated in humans. α-Tocopherol has three stereocenters, so it is a chiral molecule. The eight stereoisomers of α-tocopherol differ the configuration on these stereocenters. "RRR"-α-tocopherol is the natural one. Older name of "RRR"-α-tocopherol is "d"-α-tocopherol,
Tocopherol (and eight possible stereoisomers per structural formula, again, only one of which occurs naturally). Each form has a different biological activity. In general, the unnatural l-isomers of tocotrienols lack almost all vitamin activity, and half of the possible 8 isomers of the tocopherols (those with 2S chirality at the ring-tail junction) also lack vitamin activity. Of the stereoisomers which retain activity, increasing methylation, especially full methylation to the alpha-form, increases vitamin activity. In tocopherols, this is due to the preference of the tocopherol binding protein for the alpha-tocopherol form of the vitamin. As a food additive, tocopherol is labeled with