ABSTRACT
Vitamin E is a generic term referring to an entire class of compounds that is further divided into two groups called tocopherols and tocotrienols. There are at least eight different isoforms of vitamin E: alpha-, beta-, gamma-and delta-tocopherols and alpha-, beta-, gamma-and delta-tocotrienols. Each tocotrienol molecule differs from the corresponding tocopherol molecule onlyin the side chain. Tocopherols have a saturated side chain, a phytyl group attached to their chromanol ring, while the side chain of tocotrienolsis unsaturated and forms an isoprenoid group. Theisoforms of tocotrienols differ in their methyl substituentson the chromanol ring. The alpha-form involves three methyl groups,while the beta-and gamma-have two and delta-form only one methylgroup. Each of these forms has a reportedly differentbiopotency (Azzi and Stocker 2000; Brigelius-Flohe and Traber1999).
