Complexity of vitamin E metabolism.
- Citation Copy to clipboard
Schmolz L, Birringer M, Lorkowski S, Wallert M
Complexity of vitamin E metabolism.
World J Biol Chem. 2016 Feb 26;7(1):14-43. doi: 10.4331/wjbc.v7.i1.14.
- PubMed ID
- 26981194 [ View in PubMed]
Bioavailability of vitamin E is influenced by several factors, most are highlighted in this review. While gender, age and genetic constitution influence vitamin E bioavailability but cannot be modified, life-style and intake of vitamin E can be. Numerous factors must be taken into account however, i.e., when vitamin E is orally administrated, the food matrix may contain competing nutrients. The complex metabolic processes comprise intestinal absorption, vascular transport, hepatic sorting by intracellular binding proteins, such as the significant alpha-tocopherol-transfer protein, and hepatic metabolism. The coordinated changes involved in the hepatic metabolism of vitamin E provide an effective physiological pathway to protect tissues against the excessive accumulation of, in particular, non-alpha-tocopherol forms. Metabolism of vitamin E begins with one cycle of CYP4F2/CYP3A4-dependent omega-hydroxylation followed by five cycles of subsequent beta-oxidation, and forms the water-soluble end-product carboxyethylhydroxychroman. All known hepatic metabolites can be conjugated and are excreted, depending on the length of their side-chain, either via urine or feces. The physiological handling of vitamin E underlies kinetics which vary between the different vitamin E forms. Here, saturation of the side-chain and also substitution of the chromanol ring system are important. Most of the metabolic reactions and processes that are involved with vitamin E are also shared by other fat soluble vitamins. Influencing interactions with other nutrients such as vitamin K or pharmaceuticals are also covered by this review. All these processes modulate the formation of vitamin E metabolites and their concentrations in tissues and body fluids. Differences in metabolism might be responsible for the discrepancies that have been observed in studies performed in vivo and in vitro using vitamin E as a supplement or nutrient. To evaluate individual vitamin E status, the analytical procedures used for detecting and quantifying vitamin E and its metabolites are crucial. The latest methods in analytics are presented.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Vitamin E SEC14-like protein 4 Protein HumansUnknown Not Available Details
- Drug Enzymes
Drug Enzyme Kind Organism Pharmacological Action Actions alpha-Tocopherol acetate Cytochrome P450 3A4 Protein HumansNoSubstrate Details alpha-Tocopherol acetate Leukotriene-B(4) omega-hydroxylase 1 Protein HumansNoSubstrate Details Tocofersolan Cytochrome P450 3A4 Protein HumansNoSubstrate Details Tocopherol Cytochrome P450 3A4 Protein HumansNoSubstrate Details Tocopherol Leukotriene-B(4) omega-hydroxylase 1 Protein HumansNoSubstrate Details
- Drug Carriers
Drug Carrier Kind Organism Pharmacological Action Actions alpha-Tocopherol acetate Low-density lipoprotein receptor Protein HumansNoBinder Details alpha-Tocopherol acetate Very low-density lipoprotein receptor Protein HumansNoBinder Details Tocopherol Low-density lipoprotein receptor Protein HumansNoBinder Details Tocopherol Very low-density lipoprotein receptor Protein HumansNoBinder Details
- Drug Transporters
- Drug Reactions
Reaction Details Details Details Details Details