Vitamin like compounds like choline and Lipoic acid

Choline and lipoic acid

1. VITAMINLIKE
COMPOUNDS
CHOLINEANDLIPOICACID

2. CHOLINE:
•Synthesisedinbodyhencenotavitamin.
•ConventionallyincludedasamemberofvitaminBcomplex
•Activeroleintransmethylation.
•Watersoluble

3. STRUCTURE:
•Hydroxyethyltrimethylamineortrimethylethanolamine

4. SOURCES:
•synthesizedinthebodyfromserine
•Othersources:ricepolishing,vegetables,milk,eggandliver

5. Biochemicalfunctionsofcholine:
•Phospholipidsynthesis:cholineispartofphospholipid
•Sincemyelinsheathismadeupbyphospholipids,itrequirescholine
•Preventfattyliverandcirrhosisbytransportingfatandcholesteroloutof
liver
•Transmethylationreactions:
Cholinedonates3methylgroupstoone
carbonpool
Thesemethylgroupsaretransferredto
homocysteineandmethionineisformed
Methionineislaterusedfortransmethylation

6. Cont.:
•Acetylcholinesynthesis:
Choline+acetylCoA
Cholineacetylase
Acetylcholine+CoA
Acetylcholine
Acetylcholinesterase
Choline+acetate

7. ACETYLCHOLINE(ACh)
•Itisaneurotransmitter
•Synthesisedinneurons
•Storedinvesiclesatpresynapticregion
•AChisreleasedintosynaptosomewhennerveimpulsereaches
•HencethenerveimpulseistransmittedthroughthesynapseviaAch
•TheAchreleasedthengetshydrolysedbyAchesterase

8. ClinicalapplicationsofACh:
1.SuccinylcholinecompetitivelyinhibitsAchbybindingtoAch
receptorsandhencemusclecannotcontract.Itisusedasa
musclerelaxant.
2.Cholinestraseinhibitors(e.g.neostigmine)exhibitprolonged
inhibitionofAchandareusedinmyastheniagravis.
3.PseudocholinesteraseisseenimmatureRBCs

9. LIPOICACID:
•Alsocalledalphalipoicacid(ALA)
•Bothwatersolubleandfatsoluble.
•Getsconvertedtoactiveform‘dihydrolipoicacid’by‘lipoylation’with
thehelpofenzymecomplexespyruvatedehydrogenasecomplex(PDC)and
alphaketogutaratedehydrogenasecomplex(KGDH)
•Producedinbody(endogenousproduction)
•Importantantioxidant

10. STRUCTURE:
•Itconsistsoftwothiol(sulfhydryl)groups,whichareattachedtoadjacent
carbonatomsinaneight-carbonchain.
•Thestructureisoftendepictedasadithiolaneringwithacarboxylicacidgroup
atoneend.
•ThisuniquestructureallowsALAtofunctionbothinwater-solubleand
fat-solubleenvironments,makingithighlyversatileinitsbiologicalroles.

11. SOURCES:
•Producedinbodybutthatalonemaynotmeetthedailyrequirement
•Organmeat(liver,kidney)
•Spinach(greenleafyvegetables)
•Broccoli
•Tomatoesetc

12. DIGESTIONANDABSORPTIONOFLIPOICACID:
•Lipoicacidisboundwithproteinsandtheproteolyticenzymes
cleavethecovalentbonds
•Absorptionmaybepassiveoractive
•Passivelyabsorbedbyenterocytes
•Activelyabsorbedalongwithsodium,vitB5andB7bySMVT
carrierprotein

13. BIOCHEMICALFUNCTIONS:
•Coenzymeofpyruvatedehydrogenaseandkrebscycleenzymes
•Potentantioxidant,alsoregeneratesotherantioxidantslikevitE
andvitE
•Increaseglucosemetabolismbyincreasinginsulinsensitivity
•Neuroprotectivefunction(preventalzheimers)bypreventing
oxidationofneurons
•MetabolismandDetoxificationofxenobiotics

14. DEFICIENCYDISORDERSOFLIPOICACID:
•Usuallydeficiencydisordersarenotseensinceitisproducedinendogenously
•Deficiencymaycauseoxidativestress
•Causesofcholinedeficiencymaybe:
Severemalnutrition
AbsorptiondisordersinGItract
Heavymetaltoxicity
Geneticdisorders
Chronicalcoholabuse