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Che m ic a l n a tu r e:

Vitamin E is lipophilic in character and is found in association with lipoproteins, fat deposits and cellular membranes. Che m ic a l n a tu r e:. Vitamin E is chemically known as tocopherol (Greek: tocos= childbirth , piro= to bear and ol= alcohol ) An alcohol was capable to prevent

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Che m ic a l n a tu r e:

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  1. VitaminEislipophilicincharacterandisfoundinassociationwithlipoproteins,fatdepositsandcellularmembranesVitaminEislipophilicincharacterandisfoundinassociationwithlipoproteins,fatdepositsandcellularmembranes

  2. Chemicalnature: • VitaminEischemicallyknownastocopherol(Greek:tocos=childbirth,piro=tobearandol=alcohol) • Analcoholwascapabletoprevent • reproductivefailureinanimals • Henceitisknownasanti-sterilityvitamin • Chemistry: • VitaminEisthenamegiventogroupoftocopherolsandtocotrienols

  3. About8tocopherolshavebeenidentified • Alpha-tocopherolismostactive • Thetocopherolsarederivativesof6-hydroxychromane(tocol)ringwithisoprenoidsidechain • Theantioxidantpropertyisduetothechromanering • Therearefourmainformsoftocopherols • Theyare

  4. α -tocopherol:5,7,8trimethyltocol • β -tocopherol:5,8dimethyltocol • γ -tocopherol:7,8dimethyltocol • δ -tocopherol:8methyltocopherol • α –tocopherolismostactiveandpredominantformofvitaminE • Tocotrienols:TherearefourrelatedvitaminE • compoundscalled α,β,γ and δ tocotrienols

  5. CH3 CH3CH3 CH • 3 • CH2-(CH2-CH2-CH-CH2)3-H • OH • CH3 • α-Tocopherol(5,7,8-trimethyltocol)

  6. CH3 CH3CH3 CH2-(CH2-CH2-CH-CH2)3-H OH CH3 β-Tocopherol(5,8-dimethyltocol CH3  CH3CH3 CH2-(CH2-CH2-CH-CH2)3-H CH 3 OH γ-Tocopherol(7,8-dimethyltocol)

  7. ABSORPTION • VitaminEisabsorbedalongwithfatinthe • uppersmallintestine • Mechanism:VitaminEcombineswithBilesalts(micelles)toformmixedmicelleandtakenupbythemucosalcell • Inthemucosalcell,itisincorporatedinto • chylomicrons

  8. DietaryvitaminEisincorporatedtochylomicrons • Inthecirculation,chylomicronstransportvitaminEtotheperipheraltissueortotheliver • HepaticvitaminEisincorporatedtoVLDL • Inthecirculation,VLDLisconvertedLDL • VitaminEistransportedwithLDLtoreachtheperipheraltissuesincludingadiposetissue

  9. Storage: • Mainlystoredinliverandadiposetissue • Presentinbiologicalmembranes,becauseofitsaffinitytophospholipids

  10. MostofthefunctionsofthevitaminEare • relatedtoitsantioxidantproperty • Itpreventsthenon-enzymaticoxidationsofvariouscellcomponentsbymolecularoxygenandfreeradicalssuchassuperoxideandhydrogenperoxide(H2O2) • Seleniumhelpsinthesefunctions • ItprotectsthePUFAfromperoxidationreactions

  11. VitaminEisessentialformembranestructureandintegrityofthecell,henceitismembraneantioxidant.VitaminEisessentialformembranestructureandintegrityofthecell,henceitismembraneantioxidant. Itpreventstheper oxidationofPUFA ItprotectstheRBCfromhemolysisby oxidizingagents(H2O2) Itisassociatedwithreproductivefunctionandpreventssterility

  12. VitaminEpreservesandmaintainsgerminalepitheliumofgonadsforproperreproductivefunctionVitaminEpreservesandmaintainsgerminalepitheliumofgonadsforproperreproductivefunction Itincreasesthesynthesisofhemebyenhancingtheactivityofenzyme– δ aminolevulinicacid(ALA)synthaseandALAdehydratase Itisrequiredforcellularrespiration–through ETC(StabilizecoenzymeQ) VitaminEpreventstheoxidationofVitaminAandcarotenes

  13. Itisrequiredforproperstorageofcreatineinskeletalmuscle Itisrequiredforabsorptionofaminoacids fromintestine Itisinvolvedinsynthesisofnucleicacids Itprotectstheliverfromtoxiccompounds suchascarbon tetra chloride. 13.ItworksinassociationwithvitaminA,Cand beta-carotene,todelaytheonsetofcataract

  14. 14.VitaminEisrecommendedforthe • preventionofchronicdiseasessuchascancer • andheartdisease • VitaminEpreventsoxidationofLDL • OxidizedLDLpromotesheartdiseases • Selinium:Itisacomponentofglutathioneperoxidaseandfunctionasantioxidant • ItreducestherequirementofvitaminEindiet • ItisrequiredfornormalpancreaticfunctionandenhancingtheabsorptionofvitaminE

  15. -10mg/day • 8mg/day • 10mg/day • 12mg/day • Males • Females • Pregnancy • Lactation • 15mgofvitaminEisequivalentto33IU • Pharmacologicaldoseis200-400IU/day • Sources: • Richsourcesarevegetableoils • Includesgermoil,sunfloweroil,cornoilandmargarine

  16. Inhumans,deficiencyofvitaminEisseenin • Prematureinfants: • TransferofvitaminEfrommaternalbloodoccursduringlastfewweeksofpregnancy • PrematureinfantswillhavevitaminEdeficiency • Impairedabsorption:Seeninconditionssuchas • abetalipoproteinemia(fatmalabsorption) • Obstructivejaundice • Intestinaldiseasessuchasceliacspure DEFICIENCY

  17. GeneticvitaminEdeficiency:ItiscausedbylackofaproteinthatnormallytransportsGeneticvitaminEdeficiency:Itiscausedbylackofaproteinthatnormallytransports • α-tocopherolfromhepatocytestoVLDL • Clinicalfeatures: • Hemolyticanemiaormacrocyticanemiaseen • inprematureinfants • Inadults,increasedsusceptibilityofRBCs to hemolysisunderoxidativestress. • Muscleweaknessandproteinuriaisseen

  18. Musculardystrophy • VitaminEdeficiencyleadstoincreasedoxidationofPUFA,withconsumptionofoxygenandproductionofperoxides • Peroxidesincreasetheintracellularhydrolase • activity, which catalyzebreakdownsinmuscleandproducemusculardystrophy • Themusclecreatineislowandcreatinuriaoccurs

  19. Hepaticnecrosis • VitaminEandseleniumpreventshepaticnecrosis • Cerebellarataxiaandimpairedvision: • Chronicdeficiencyinchildrenisassociatedwithataxia,weakness,lossoftouchandpositionsenses,impairedvisionandretinopathy • Increasedlipidperoxidationinnervoustissuecausesneurologicallesions

  20. OxidationofPUFAinrodsleadstooxidativedamageinretina • Deficiencyinanimals: • Musculardystrophyandreproductivefailure • VitaminEisleasttoxic

  21. TherapeuticusesofvitaminE

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