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| Names | |
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| Preferred IUPAC name (2R)-2,5,7,8-Tetramethyl-2-[(4R,8R)-4,8,12-trimethyltridecyl]-3,4-dihydro-2H-1-benzopyran-6-ol | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL |
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| ChemSpider |
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| DrugBank |
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| ECHA InfoCard | 100.000.375 |
| EC Number |
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| E number | E307a(antioxidants, ...) |
| UNII | |
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| Properties | |
| C29H50O2 | |
| Molar mass | 430.71 g/mol |
| Appearance | yellow-brown viscous liquid |
| Density | 0.950 g/cm3 |
| Melting point | 2.5 to 3.5 °C (36.5 to 38.3 °F; 275.6 to 276.6 K) |
| Boiling point | 200 to 220 °C (392 to 428 °F; 473 to 493 K) at 0.1 mmHg |
| insoluble | |
| Solubility | soluble in alcohol,ether,acetone, oils |
| Pharmacology | |
| A11HA03 (WHO) | |
| Hazards | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
α-Tocopherol (alpha-tocopherol) is a type ofvitamin E. ItsE number is "E307". Vitamin E exists in eight different forms, fourtocopherols and fourtocotrienols. All feature achromane ring, with a hydroxyl group that can donate a hydrogen atom to reduce free radicals and a hydrophobic side chain, along with an aromatic ring is situated near the carbonyls in the fatty acyl chains of the phospholipid bilayer, allows for penetration into biological membranes.[2] It is found most in the membrane's non-raft domains, associated with omega-3 and 6 fatty acids, to partially prevent oxidation.[3] The most prevalent form, α-tocopherol, is involved in molecular, cellular, biochemical processes closely related to overalllipoprotein andlipidhomeostasis. Compared to the others, α-tocopherol is preferentially absorbed and accumulated in humans.
Vitamin E is found in a variety of tissues, being lipid-soluble, and taken up by the body in a wide variety of ways. Ongoing research is believed to be "critical for manipulation of vitamin E homeostasis in a variety of oxidative stress-related disease conditions in humans."[4] One of these disease conditions is the α-tocopherol role in the use bymalaria parasites to protect themselves from the highly oxidative environment inerythrocytes.[5] A second of these disease conditions is the α-tocopherol antioxidant properties' role cardiovascular heart disease. In preventing LDL (low-densitylipoprotein) oxidation, it is able to decrease chances of atherosclerosis and arterial build-up.[6]
To synthesize the ⍺-diastereomer selectively, tocol acetate is transformed to the naturally occurring, kinetically favored α-tocopherol after being catalyzed by the lipase enzyme. This reaction occurs under biological conditions, commonly in the digestive system.[7]
α-Tocopherol has threestereocenters, so it is achiral molecule.[8] The eightstereoisomers of α-tocopherol differ in the configuration of these stereocenters.RRR-α-tocopherol is the natural one.[9] The older name ofRRR-α-tocopherol isd-α-tocopherol, but thisd/l naming should no longer be used, because whetherl-α-tocopherol should meanSSS enantiomer or theSRR diastereomer is not clear, from historical reasons. TheSRR may be named 2-epi-α-tocopherol, the diastereomeric mixture ofRRR-α-tocopherol and 2-epi-α-tocopherol may be called 2-ambo-α-tocopherol (formerly nameddl-α-tocopherol). The mixture of all eight diastereomers is calledall-rac-α-tocopherol.[10] The α-Tocopherol is the most active diastereomer biologically, while being maintained at a high level in plasma and tissues of many different animal species.[11]
One IU of tocopherol is defined as2⁄3 milligram ofRRR-α-tocopherol (formerly namedd-α-tocopherol). 1 IU is also defined as 0.9 mg of an equal mix of the eight stereoisomers, which is aracemic mixture,all-rac-α-tocopheryl acetate. This mix of stereoisomers is often calleddl-α-tocopheryl acetate.[12] Starting with May 2016, the IU unit is made obsolete, such that 1 mg of "Vitamin E" is 1 mg of d-alpha-tocopherol or 2 mg of dl-alpha-tocopherol.[13]
