Term
| Chromanol (alcohol)ring structure with (-OH) in position 6 + side chain with isoprenoid units (phytyl) is characterized to what vitamin? |
|
Definition
|
|
Term
| Vit E Family include ? And how many? |
|
Definition
4 Tocopherols
alpha
beta
gamma
delta
+
4 Tocotrienols
alpha
beta
gamma
delta
=
VITAMIN E FAMILY
(8 members) |
|
|
Term
| The OH group in Vit E is important for what? |
|
Definition
|
|
Term
| TE (Tocoherol Equivalents) = __ mg alpha tocopherol |
|
Definition
| 1TE=1 mg alpha tocopherol |
|
|
Term
| Why only alpha-tocopherol is Vit E for humans? |
|
Definition
| Only the stereoisomers (tail is in 2R configuration) of alpha tocopherol are maintained in human body. |
|
|
Term
|
Definition
RRR-α-tocopherol (d-α-tocopherol)
IN FOODs
- formed by methylating gamma tocopherol extracted from vegetable oil. |
|
|
Term
Synthetic Vit E
What form is it usually in? |
|
Definition
all-rac-α-tocopherol
8 stereoisomers: RRR, RRS, RSR, RSS, SRR, SSR, SRS, SSS
1/2 as good as natural
- produced by coupling trimethylhydroquinone with isophytol
- 8 stereoisomers in equal emount
- Found in fortified food
- usually in ester form (acetate) |
|
|
Term
| Why is synthetic form of Vit E is only 1/2 as good? |
|
Definition
Natural Vit E: one stereoisomeric form
Synthetic: 8 possible stereoisomers, but serum and tissues only maintain 4 four, of these stereoisomers. So synthetic Vit E (DL or dl) is only 50% active as same amount of natural Vit E (D or d) *by wt in mg
- ppl need 50% more IU of synthetic α-tocopherol |
|
|
Term
|
Definition
| 15 mg/ day (30 if its all rac α tocopherol) |
|
|
Term
| Vit E absorption and delivery to tissues? |
|
Definition
1. Vit E absorption required BILE ACID, FATTY ACIDs, and MONOglycerides for micelle formation
2. Once Vit E is taken in by enterocytes, all formas of dietary Vit E are incorporated into Chylomicrons
3. CM are secreted into the circulation
4. In circulation--> lypolysis by LPL bound to the endothelial lining of capilarry walls takes place
5. Resulted CM taken up by liver
6. During lipolysis: various forms of Vit E can be transferred to tissues, or to HDL
7. Vit E can exchange between HDL or other circulation lipoproteins, which can also deliver vit E to peripheral tissues |
|
|
Term
| Circulating HDL and other lipoproteins can also deliver Vit E to tissues. T of F |
|
Definition
|
|
Term
| Draw absorption and delivery of Vit E. Page 6 |
|
Definition
|
|
Term
| How is α-tocopherol delivered to tissues? |
|
Definition
1. CM remnants with Vit E (various forms) are taken up by LIVER
2. α-TTP prefers to take α-tocopherol into naschent VLDL
3. When VLDL secreted in PLASMA, lypolysis of VLDL by LPL and hepatic TG lipase result in preferred enrichment of circulating lipoproteins with α-tocopherol and its delivery to tissues. |
|
|
Term
| Draw the delivery of VIt E diagram. Page 7 |
|
Definition
|
|
Term
| How much Vit E is absorbed? (%) |
|
Definition
| About 20-40 % of dietary vit E |
|
|
Term
| How is α-tocopherol mainly transported? |
|
Definition
| Via VLDL fraction in plasma |
|
|
Term
|
Definition
Vit E stored in
- adipose (FAT)
- Liver
- Muscle |
|
|
Term
| Vit E is found in tissues mainly in what form? |
|
Definition
| As Free tocopherols, in cell membranes |
|
|
Term
| How is Vit E excreted and in what form? |
|
Definition
In
bile
urine as derivatives of tocopherol quinone. |
|
|
Term
|
Definition
Antioxidant Function:
- Major membrane bound, lipid soluble antioxidant
- it is a hydroxy/peroxyl radical trapping and chain breaking antioxidant
- Oxidized Vit E is regenerated by the glutathone system or vit C
Structure specific functions:
- regulation of vascular smooth muscle cell proliferaton
- Prtein Kinase C activity
- Arachidonic acid metabolism (inhibition of phospholipase A2)
- Degragation of HMG-CoA reductase
- Gene expression? |
|
|
Term
| What is the major membrane bound, lipid souluble antioxidant? |
|
Definition
|
|
Term
| Which antioxidant is hydroxyl/peroxyl radical trapping and chain breaking? |
|
Definition
|
|
Term
| Degragation of HMG- CoA reductase? Which Vitamin |
|
Definition
|
|
Term
| Arachidonic acid metabolism *inhibition of phospholipase A2, which vitamin? |
|
Definition
|
|
Term
| Regulation of smooth muscle cell proliferation, which vitamin? |
|
Definition
|
|
Term
| Importance in Protein Kinase C activity, which vitamin? |
|
Definition
|
|
Term
Lipid Peroxidation VIT E?
What is the end product? |
|
Definition
Initiation: Production of R*
- due to attack of things that capable of taking H from UNsaturated FA to from Carbon centered radical
Propagation:
Carbon-centered radical reacts fast with O2
R+O2 --> R-OO
- a fatty acid peroxyl radical is formed. This can attack adjacent FA side chain and promote peroxidation
R-OO + RH--> R-OO-H +R
This chain Rx continues, lipid hydroperodides (R-OO-H) destabilze membrane--> leaky
Termination:
Requires chain breaking antioxidant
R-OO + αTH--> R-OO-H + α T
ENd product: ethane, pentane, MDA |
|
|
Term
Vit E needs what to regenerate?
It produces VIt E and _____? |
|
Definition
Vit C, glutothione
Dehydro ascorbate |
|
|
Term
| Why can't Saturated FA be oxidized? |
|
Definition
| Becaue oxidation happens at the double bond |
|
|
Term
| What does AVED stand for? |
|
Definition
| Ataxia w/ Vit E deficiency |
|
|
Term
| Deficiency of Vit E: Defects in lipoprotein synthesis |
|
Definition
Apoliprot B: rapid turnonver of B lipoprotein in plasma
(homozygous hypobetalipoprotenemia)
- microsolmal TG transfer protein (abetalipoproteinemia): No B lipoproteins in plasma
- both develop a progressive peripheral neuropathy
- must supplement with VitE |
|
|
Term
|
Definition
| Rapid turnover of B lipoprotein in plasma |
|
|
Term
|
Definition
| no B lipoprotein in plasma--> develop progressive peripheral neuropathy |
|
|
Term
| Fat malabsorption syndrome and Vit E |
|
Definition
Who:
Children w/ cholestatic liver disease
Children w/cystic fibrosis
Bowel resection, Crohn's disease, celiac disease
TPN
Treat:
RRR-α-tocopherol (not the ester)
Water soluble form: tocopherol polyethylene glycol 1000 succinate (TPGS)
- Intramuscular injection: Viprimol |
|
|
Term
| What is a water soluble name for Vit E? |
|
Definition
TPGS
Tocopherol polyethylene glycol 1000 succinate |
|
|
Term
| Disorders in which Vit E is beneficial (lucky 7)? |
|
Definition
Premature infants-retinopathy of prematurity
- protetion from retrolental fibroplasia
- possible protection from intraventricular hemorrhage
Anemia of prematurity:
- physiological jaundice anemia of newborns
CV disorders:
decreased risk of CHD
decreasedin vitro LDL oxi
decreased in vitro platelet aggrigation
Ischemia-reperfusion injury (blood supply cut off, then comes back)
Immune response
Cataract
Tardive dyskenesia (involuntary, repetitive body movements) |
|
|
Term
| What is EAR, DRA and UL of Vit E? |
|
Definition
EAR: 12 mg/d
RDA: 15 mg/d
UL: 1000 mg/day |
|
|
Term
|
Definition
| α tocopherol inhibits oxidation of LDL in vitro |
|
|
Term
| What causes free radical? |
|
Definition
| inflammation, phagocytosis, detox enzymes, mitochondria, smoking, uv, smog, radiation, chemicals |
|
|
Term
|
Definition
O2 is involved in making reactive oxy species (ROS) and reactive N species (RNS)
- contain one or more unpaired e
- highly reactive |
|
|
Term
| Physiological Antioxidant System: Endogenous |
|
Definition
Active system
Enzymes: catalase,superoxide dismutase, glutathione peroxide, paraoxonase
Passive system:
Uric acid, createnine, bilirubin, melatonin, glutathione NAD(p)H, lipoic acid, CoQ, albumin, transferin, ceruloplasmin, haptoglobin |
|
|
Term
| Physiological Antioxidant System: Exogenous |
|
Definition
Nutrients: Vit E, Carotenoids, Vit C
- Dietary biocactive components: polyphenols |
|
|
Term
| What is body's antioxidant defense in Plasma? |
|
Definition
Vit C (ascorbic acid)
B- carotene and other carotenoids
Plasma proteins
Uric Acid
Bioactive plant compoinds
Enzyme system:
ceruloplasmin
Superoxide dismutase
Glutathione peroxidase |
|
|
Term
| What is body's antioxidant defense in Membrane? |
|
Definition
α-tocopherol or Vit E
beta carotene |
|
|
Term
| What is body's antioxidant defense Intracellularly? |
|
Definition
GLUTATHIONE
enzyme system: superoxide dismutase
catalase
glutathione peroxidase |
|
|
Term
| How are Free radicals useful? |
|
Definition
Respiratory chain
NO (from arginine)--> vasodilator
Phagocytic cells: produce superoxide which helps inactivate viruses and bacteria |
|
|
Term
| Biomarker for lipid oxidation? |
|
Definition
TBARS
breath hydrocarbons
LDL resistance to oxidation
F2 isoprostanes
ORAC, FRAP |
|
|
Term
| Biomarker for DNA oxidation? |
|
Definition
8 OHdG
antibodies to oxidize DNA
Comet assay (dna strand breaks, dna oxi) |
|
|
Term
| Biomarker for protein oxidation? |
|
Definition
|
|
Term
| Formation and Removal of OH, Singlet oxygen O2 and Superoxide? |
|
Definition
OH:
Form: ionizing rediation
Remove: ascorbic acid, carotenoids
Singlet Oxy O2:
Form: light energy
Remove: Vit E, carotenoids
Superoxide O2:
Form: phagocytosis, metabolic reactions
Remove: Superoxide dismutase SOD |
|
|
Term
|
Definition
Form: SOD enzyme, oxidase enzyme
Remove:
1. Catalase (Fe) in peroxisomes of cells
2. Glutathione peroxidase system:
enzyme glutathione peroxidase destroys OH
1. GSH (reduced)--> GSSG (oxidized)
2. GSSG (oxidized) is re generted by glutathione reductase
Glutathione peroxidase also destroys lipid hydroperoxides |
|
|
Term
| Glutathione peroxidase system? |
|
Definition
Enzyme: Glutathione peroxidase destroys hydrogen peroxide
1. GSH--> GSSG (reduced-->oxi)
2. GSSG *oxidized is re-generated by glutathione reductase
GSSG+NADPH--> GSH + NADP
Glutathione peroxidase also destroys lipid hydroperoxides |
|
|
Term
|
Definition
Reduced: GSH (tripeptide, in most cells)
Can scavange free radicals directly and its part of the glutathione peroxidase system
Glutamate+cystein+glycine |
|
|
