Molecules having vitamin E antioxidant activity include four tocopherols (α, β, δ, and γ) and four tocotrienols (α, β, δ, and γ).
1 α-
Tocopherol is the major lipid soluble antioxidant
in vivo and protects against lipid peroxidation.
2 α-
CEHC is the major urinary metabolite of α-
tocopherol following vitamin E supplementation.
3 The concentration of α-
CEHC in human serum is in the range of 5-
10 pmol/ml but increases significantly up to 200 pmol/ml upon supplementation with RRR-
α-
tocopherol. About one-
third of the α-
CEHC circulating in the blood is present as a glucuronide conjugate.
4 α-
CEHC was only excreted when a threshold concentration of 7-
9 μmol α-
tocopherol/g total lipid in plasma was exceeded. Therefore, excretion of α-
CEHC may be considered to be a marker of optimum vitamin E intake.
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