Vitamin E (Tocopherols/Tocotrienols)

Vitamin E is a family of eight fat-soluble compounds, categorized into:

• Tocopherols: Four compounds distinguished by methyl group patterns on the chromanol ring and a saturated phytyl side chain.
• Tocotrienols: Four compounds distinguished by methyl group patterns on the chromanol ring and an unsaturated phytyl side chain.

These compounds primarily function as lipid-soluble antioxidants, protecting cellular membranes from oxidative injury, and modulating signaling pathways influencing:

• Inflammation
• Gene expression
• Immune function

• Structure: Vitamin E compounds share a chromanol head (C₆H₈O₂) linked to a 16-carbon side chain.
• α-tocopherol: IUPAC name is (2R)-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridec-2-enyl)chroman-6-ol.
• Tocotrienols: Differ by three double bonds in the side chain, giving them higher membrane fluidity.
• Molecular Formulas:
  • α-tocopherol: C₂₇H₄₈O₂ (M = 430.71 g·mol⁻¹)
  • α-tocotrienol: C₂₇H₄₆O₂ (M = 428.69 g·mol⁻¹)
• Active Moiety: The phenolic hydroxyl is the active antioxidant moiety.
• Lipid Localization: The hydrophobic side chain drives lipid-phase localization.
• Tocotrienol Advantage: Tocotrienols possess a conjugated diene system, enhancing free-radical scavenging and membrane incorporation compared with tocopherols.

• Natural Sources: Extracted from plant oils rich in tocopherols (e.g., soybean, sunflower, wheat germ) and from palm oil, which contains high levels of tocotrienols.
• Commercial Production: Uses solvent extraction (hexane) followed by saponification, filtration, and distillation to isolate mixed tocopherols or tocotrienols.
• Synthetic α-tocopherol: Synthetic “all-rac” α-tocopherol (dl-α-tocopherol) is produced via chemical synthesis, yielding a racemic mixture with lower bioactivity than natural d-α-tocopherol.
• Quality Assessment:
  • Verification of the d-α-tocopherol proportion (≥ 90 % for high-quality natural products).
  • Verification of the tocotrienol content (≥ 50 % in tocotrienol-rich extracts).
• Labeling: Certified “natural” (e.g., “d-α-tocopherol”) and “tocotrienol-rich” labels ensure minimal oxidation and accurate potency.