Target type: biologicalprocess
The chemical reactions and pathways involving vitamin E, tocopherol, which includes a series of eight structurally similar compounds. Alpha-tocopherol is the most active form in humans and is a powerful biological antioxidant. [GOC:jl, ISBN:0198506732]
Vitamin E, a group of eight fat-soluble compounds including tocopherols and tocotrienols, plays a crucial role in protecting cells against oxidative damage. The metabolic process of vitamin E involves absorption, transport, and utilization in the body.
**Absorption and Transport:**
- Vitamin E is absorbed from the small intestine along with dietary fats.
- In the intestinal lumen, vitamin E is incorporated into micelles formed by bile salts and dietary lipids.
- Once absorbed, vitamin E is transported to the liver via chylomicrons, lipoproteins that carry dietary lipids.
- In the liver, vitamin E is transferred to very low-density lipoproteins (VLDLs) and low-density lipoproteins (LDLs), which deliver it to tissues throughout the body.
**Utilization and Function:**
- Vitamin E primarily functions as an antioxidant, protecting cells from damage caused by reactive oxygen species (ROS) such as free radicals.
- It acts as a chain-breaking antioxidant, donating a hydrogen atom to a free radical, thereby stabilizing it and preventing further damage.
- Vitamin E also plays a role in regulating gene expression, cell signaling, and immune responses.
**Metabolism and Excretion:**
- Vitamin E is not metabolized extensively in the body.
- Small amounts of vitamin E are metabolized in the liver, with some degradation products excreted in the bile and urine.
- The majority of vitamin E is stored in adipose tissue, liver, and other tissues.
**Factors Affecting Vitamin E Metabolism:**
- Dietary intake of vitamin E
- Fat malabsorption
- Liver disease
- Genetic factors
**Health Implications:**
- Vitamin E deficiency can lead to a range of health problems, including hemolytic anemia, nerve damage, and impaired immune function.
- Excessive vitamin E intake can lead to bleeding and other adverse effects.
- Maintaining adequate vitamin E levels is important for overall health and well-being.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Alpha-tocopherol transfer protein | An alpha-tocopherol transfer protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:P49638] | Homo sapiens (human) |
| NPC1-like intracellular cholesterol transporter 1 | An NPC1-like intracellular cholesterol transporter 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UHC9] | Homo sapiens (human) |
| Cytochrome P450 4F2 | A cytochrome P450 4F2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P78329] | Homo sapiens (human) |
| NAD | An NAD(P)H dehydrogenase [quinone] 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P15559] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 17-octadecynoic acid | octadec-17-ynoic acid : An acetylenic fatty acid that is octadecanoi acid (stearic acid) which has been doubly dehydrogenated at positions 17 and 18 to give the corresponding alkynoic acid. | acetylenic fatty acid; long-chain fatty acid; monounsaturated fatty acid; terminal acetylenic compound | EC 1.14.14.94 (leukotriene-B4 20-monooxygenase) inhibitor; EC 1.14.15.3 (alkane 1-monooxygenase) inhibitor; P450 inhibitor |
| 4'-bromoflavone | 4'-bromoflavone: structure in first source | ||
| beta-naphthoflavone | beta-naphthoflavone : An extended flavonoid resulting from the formal fusion of a benzene ring with the f side of flavone. beta-Naphthoflavone: A polyaromatic hydrocarbon inducer of P4501A1 and P4501A2 cytochromes. (Proc Soc Exp Biol Med 1994 Dec:207(3):302-308) | extended flavonoid; naphtho-gamma-pyrone; organic heterotricyclic compound | aryl hydrocarbon receptor agonist |
| ketoconazole | 1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine : A dioxolane that is 1,3-dioxolane which is substituted at positions 2, 2, and 4 by imidazol-1-ylmethyl, 2,4-dichlorophenyl, and [para-(4-acetylpiperazin-1-yl)phenoxy]methyl groups, respectively. | dichlorobenzene; dioxolane; ether; imidazoles; N-acylpiperazine; N-arylpiperazine | |
| beta-lapachone | beta-lapachone : A benzochromenone that is 3,4-dihydro-2H-benzo[h]chromene-5,6-dione substituted by geminal methyl groups at position 2. Isolated from Tabebuia avellanedae, it exhibits antineoplastic and anti-inflammatory activities. beta-lapachone: antineoplastic inhibitor of reverse transcriptase, DNA topoisomerase, and DNA polymerase | benzochromenone; orthoquinones | anti-inflammatory agent; antineoplastic agent; plant metabolite |
| vitamin k 3 | Vitamin K 3: A synthetic naphthoquinone without the isoprenoid side chain and biological activity, but can be converted to active vitamin K2, menaquinone, after alkylation in vivo. | 1,4-naphthoquinones; vitamin K | angiogenesis inhibitor; antineoplastic agent; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; human urinary metabolite; nutraceutical |
| sulforaphane | sulforaphane : An isothiocyanate having a 4-(methylsulfinyl)butyl group attached to the nitrogen. sulforaphane: from Cardaria draba L. | isothiocyanate; sulfoxide | antineoplastic agent; antioxidant; EC 3.5.1.98 (histone deacetylase) inhibitor; plant metabolite |
| dehydroepiandrosterone | dehydroepiandrosterone : An androstanoid that is androst-5-ene substituted by a beta-hydroxy group at position 3 and an oxo group at position 17. It is a naturally occurring steroid hormone produced by the adrenal glands. Dehydroepiandrosterone: A major C19 steroid produced by the ADRENAL CORTEX. It is also produced in small quantities in the TESTIS and the OVARY. Dehydroepiandrosterone (DHEA) can be converted to TESTOSTERONE; ANDROSTENEDIONE; ESTRADIOL; and ESTRONE. Most of DHEA is sulfated (DEHYDROEPIANDROSTERONE SULFATE) before secretion. | 17-oxo steroid; 3beta-hydroxy-Delta(5)-steroid; androstanoid | androgen; human metabolite; mouse metabolite |
| d-alpha tocopherol | (R,R,R)-alpha-tocopherol : An alpha-tocopherol that has R,R,R configuration. The naturally occurring stereoisomer of alpha-tocopherol, it is found particularly in sunflower and olive oils. tocopherol : A collective name for a group of closely related lipids that contain a chroman-6-ol nucleus substituted at position 2 by a methyl group and by a saturated hydrocarbon chain consisting of three isoprenoid units. They are designated as alpha-, beta-, gamma-, and delta-tocopherol depending on the number and position of additional methyl substituents on the aromatic ring. Tocopherols occur in vegetable oils and vegetable oil products, almost exclusively with R,R,R configuration. Tocotrienols differ from tocopherols only in having three double bonds in the hydrocarbon chain. vitamin E : Any member of a group of fat-soluble chromanols that exhibit biological activity against vitamin E deficiency. The vitamers in this class consists of a chroman-6-ol core which is substituted at position 2 by a methyl group and (also at position 2) either a saturated or a triply-unsaturated hydrocarbon chain consisting of three isoprenoid units. The major function of vitamin E is to act as a natural antioxidant by scavenging free radicals and molecular oxygen. Vitamin E: A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS. | alpha-tocopherol | algal metabolite; antiatherogenic agent; anticoagulant; antioxidant; antiviral agent; EC 2.7.11.13 (protein kinase C) inhibitor; immunomodulator; micronutrient; nutraceutical; plant metabolite |
| tranylcypromine | (1R,2S)-tranylcypromine : A 2-phenylcyclopropan-1-amine that is the (1R,2S)-enantiomer of tranylcypromine. tranylcypromine : A racemate comprising equal amounts of (1R,2S)- and (1S,2R)-2-phenylcyclopropan-1-amine. An irreversible monoamine oxidase inhibitor that is used as an antidepressant (INN tranylcypromine). Tranylcypromine: A propylamine formed from the cyclization of the side chain of amphetamine. This monoamine oxidase inhibitor is effective in the treatment of major depression, dysthymic disorder, and atypical depression. It also is useful in panic and phobic disorders. (From AMA Drug Evaluations Annual, 1994, p311) | 2-phenylcyclopropan-1-amine | |
| 25-hydroxycholesterol | 25-hydroxy steroid; oxysterol | human metabolite | |
| proadifen hydrochloride | |||
| pirlindole | pirlindole: RN given refers to parent cpd; synonym pyrazidol refers to mono-HCl; structure in Negwer, 5th ed, #2812 | carbazoles | |
| 7-ketocholesterol | 7-ketocholesterol : A cholestanoid that consists of cholesterol bearing an oxo substituent at position 7. 7-ketocholesterol: inhibits uptake of cholesterol in rabbit aorta | 3beta-hydroxy-Delta(5)-steroid; 3beta-sterol; 7-oxo steroid; cholestanoid | neuroprotective agent |
| cholestane-3,5,6-triol, (3beta, 5alpha, 6beta)-isomer | 3beta-hydroxy steroid; 5alpha-hydroxy steroid; 6beta-hydroxy steroid | ||
| 6-ketocholestanol | |||
| c 1303 | C 1303: DNa-binding drug; structure given indicates that the cpd should be the dimethylamino cpd, but it is named as the diethylamino cpd | ||
| ezetimibe | ezetimibe : A beta-lactam that is azetidin-2-one which is substituted at 1, 3, and 4 by p-fluorophenyl, 3-(p-fluorophenyl)-3-hydroxypropyl, and 4-hydroxyphenyl groups, respectively (the 3R,3'S,4S enantiomer). Ezetimibe: An azetidine derivative and ANTICHOLESTEREMIC AGENT that inhibits intestinal STEROL absorption. It is used to reduce total CHOLESTEROL; LDL CHOLESTEROL, and APOLIPOPROTEINS B in the treatment of HYPERLIPIDEMIAS. | azetidines; beta-lactam; organofluorine compound | anticholesteremic drug; antilipemic drug; antimetabolite |
| ys 64 | cholestan-6-oxo-3,5-diol: metabolite of 5,6-epoxycholesterol; structure in first source | cholestanoid | |
| 22s-hydroxycholesterol | (22S)-22-hydroxycholesterol : An oxysterol that is the 22S-hydroxy derivative of cholesterol. | 22-hydroxy steroid; 3beta-hydroxy-Delta(5)-steroid; oxysterol | |
| nsc 366140 | NSC 366140: a 9-methoxypyrazoloacridine; structure given in first source | ||
| cholest-5-en-3 beta,7 alpha-diol, (3beta,7beta)-isomer | 7beta-hydroxy steroid; oxysterol | ||
| 5-methoxy-1,2-dimethyl-3-((4-nitrophenoxy)methyl)indole-4,7-dione | 5-methoxy-1,2-dimethyl-3-((4-nitrophenoxy)methyl)indole-4,7-dione: structure in first source | ||
| bisantrene | |||
| 4,3',5'-tri-o-methylpiceatannol | |||
| sch 60663 | SCH 60663: structure in first source | ||
| memoquin | memoquin: structure in first source | ||
| cholenic acid dimethylamide | cholenic acid dimethylamide: binds LXRalpha receptor; structure in first source | ||
| kaf156 | ganaplacide: antimalarial | ||
| dicumarol | Dicumarol: An oral anticoagulant that interferes with the metabolism of vitamin K. It is also used in biochemical experiments as an inhibitor of reductases. | hydroxycoumarin | anticoagulant; EC 1.6.5.2 [NAD(P)H dehydrogenase (quinone)] inhibitor; Hsp90 inhibitor; vitamin K antagonist |
| ethyl biscoumacetate | Ethyl Biscoumacetate: A coumarin that is used as an anticoagulant. It has actions similar to those of WARFARIN. (From Martindale, The Extra Pharmacopoeia, 30th ed, p226) | hydroxycoumarin | |
| nsc 158393 | NSC 158393: structure given in first source |