Download Water soluble Vit. Vit C: (Ascorbic Acid)

Water soluble Vit.
Vit C: (Ascorbic Acid);
Sources: Citrus fruits, Tomatoes, Bovine milk, leafy green
vegetables
Two forms of L Ascorbic acid.
1. L- Ascorbic Acid,reduces form
2. L –Ascorbic Acid oxidized form (dehydroascorbic Acid.)
D- Ascorbic acid is biologically inactive
It is easily destroyed by cooking.
Functions
1- Vit c is essential for the production of intercellular material necessary for
wound healing and fractured bones.
2- VitC is essential for the activity of enzyme proline hydroxylase which
catalyze the conversion of proline to hydroxyproline. hydroxyproline is amino
acid vital or important in the formation of collagen
3- Vit C involved in biologic oxidation.
4- It is required for the metabolism of tyrosine.
5- It has a role in the conversion of folic acid to physiologically active form
folinic acid (tetrahydrofolate).
6- Vit C is required for bile acid formation.
7- It facilitate the absorption of iron from the intestine.
8- It acts as water soluble Antioxidant vit inhibit the formation of nitrosamine
during digestion
Deficiency: Scurvy due to defective collagen synthesis painful swollen joint,
enlargement of the junction of the rib , hemorrhage in the gum and teeth, poor
wound healing.
Deficiency: Beriberi a disease characterize by extensive damage to the
nervous, circulatory system, damage to the muscles with odema.
Peripheral neuropathy
arrested growth.
Requirement: increase during pregnancy & lactation
TPP involve in transketolation reaction
glucose metabolism.
specially in 2
Vit B2 (Riboflavin):
Found mainly in the meat, milk, and plant product. It is also
produced by bacteria usually present in the intestine.
Riboflavin is a component of two important cofactors involved in
the oxidation –reduction reaction FAD, FMN.
Function:
Flavoprotein (combination of riboflavin+ protein)
It is an enzyme shared in biological oxidation, and enter in the function of
no. of enzymes like xanthine oxidase,cytochrome C reductase,
dehydrogenase
B3(Niacin) ; (Nicotinamide)
Water soluble vit, stable in air & heat.
Sources: found mainly in meats, liver, Egg, unpolished rice
,,vegetable diet lack this vit..
Alcoholism is an important precipitating factor for niacin
deficiency .
It has been found that tryptophan in the diet contribute to the
niacin synthesis.
Function: It enter in the structure and function of two important
coenzymes NAD, NADP (coenzyme 1 & coenzymes 2) .
These enzymes are considered as a member of enzyme system
involved in the biologic oxidation as a component of electron
transport system
These two nucleotide are responsible for the transfer of H ion in the
cells. NAD remove the hydrogen and become reduced to NADH+ H.
B5 (Pantothenic Acid): Water soluble vit formed by
combination of pantoic acid and B alanin.
Sources: Liver,Kidney, Egg & milk.
Function:
It enter in the synthesis of CoA which is coenzyme for the
1. Acetylation reaction
2. lipogenesis.
.
3. Synthesis of Ach.(acetyl cholin)
4. Synthesis of Keton bodies.
5. Enter in the kreb’s cycle.
Pantotenic is acomponent of (Acp) Acyl carrier protein that
participates in fatty acid synthesis.
Deficiency: no evidence of deficiency of this vit in human because it is
widely distributed even in a restricted diet.
Vit B6 (pyridoxine)
Six compounds have vitamin B6 activity
1- Pyridoxin is present in animal foods
2- Pyridoxal (PL) (aldehyde form) is present in animal foods
3-pyridoxamine(PM)(amine form) is mostly present in plants
4-pyridoxine phosphate(PNP)
5-Pyridoxal phosphate(PLP)
6-Pyridoxamine phosphate(PMP)
PL
PLP
PLP
PMP
by enzyme kinase phosphatase
by enzyme aminotransferase oxidase
Pyridoxine,pyridoxal phosphate,pyridoxamine phosphate change
to pyridoxic acid & excreted in urine.
FUNCTION: B6 plays avital role in the function of
100 enzymes that catalyze essential chemical
reactions in the human body.
1- pyridoxine act as a coenzyme for the transaminase enzymes.
Transamination reaction : Is the transfer of amino group from α-amino acid to
α-keto acid requiring a coenzyme called pyridoxine
2- pyridoxal phosphate act as a coenzyme for decarboxylase enzyme.
3- It is essential for dehydration and desulfahydration. Of Amino Acid.
(a.a containing thiol group are cysteine , cystine and methionine)
4- It is also essential for the metabolism of Tryptophan.(formation of B3
(Niacin)
5- Pyridoxamine is involved in the metabolism of unsaturated fatty acid.
Sources: Egg,meat, fish, milk are the best group.
Deficiency: long peroid are required before any effect are noticed.
Clinical dificiency is rare because it is widely distributed and in animal and
plant diet.
Anemia (dec. Hb), anorexia, depression, mental confusion, convulsion in
infant.
Alcoholics may be deficient owing to the metabolism of ethanol to
acetaldehyde which stimulate hydrolysis of phosphate enzymes..
Long use of INH Isonicotinic acid (Anti TB) drugs lead to peripheral
neuropathy.
i.e INH impair the metabolism of vit B6 by forming hydrozone with pyridoxine
which is rapidly excreted.
Sterilization procedures lowered vit B6 conc.
Deficiency:
Peripheral neuropathy.
Hypochromic microcytic anemia
Folic Acid B9 (Folacin) (pteryglutamic acid)
Folic Acid is composed of 3 main part
1. two- nitrogenous ring. 2. p- aminobenzoic acid 3. glutamic acid.
The related vit differ in the number of glutamic acid ,the most
common occuring are
Monoglutamate
1 glutamic acid
Triglutamate
3 glutamic acid
Haptaglutamate
7 glutamic acid
A derivatives of folic acid is called folinic acid
(5,6,7,8, tetrahydrofolate) (THF) is much more active than folic acid in
stimulating erythrocyte formation.
The conversion of folic acid to its active form folinic acid is catalysed by folinic
acid reductase In which vit c act as hydrogen donor.
Some children suffer from certain type of anemia due to genetic defect of this
type of enzyme ,
ie cannot be able to convert folic to folinic acid .
Function:
1- It is a coenzyme responsible for the metabolism and synthesis of DNA(
especially during rapid cell division and growth (infancy, pregnancy, bone
marrow )),choline,serine, methionine and hemoglobin.
2- It is also involved in tyrosine metabolism.
3- It enter in the formation of erythropiosis.
4- Necessary for fertility in both men and women.
5- May help to prevent cancer as its deficiency result in DNA damage that lead
to cancer
Clinical uses: Folic acid is very imprtant in treatment of macrocytic anemia.
Deficiency might occur from
Inadequate intake., Defective absorption. , Abnormal metabolism
Ex. Macrocytic anemia of pregnancy and infancy.
Defeciency
Megaloblastic anemia
Folic Acid Antagonist:
Many drugs have been used for the treatment of malignant tumor and leukemia
,these drugs are more or less have a similar structure to the structure of folic
acid , they inhibit DNA synthesis by a competitive inhibition to certain
enzymes ,these are 6 mercaptopurine, methotrexate prevent the conversion of
dihydrofolate FH2 to
tetrahydrofolate FH4
Ie; it inhibit dihydrofolate reductase enzyme .
B12 (Cyanocobolamine):
Sources: the chief source is the liver, animal proteins milk,meat, egg
,fish.
Vit B12 containing coenzymes cobamides .
three cobamides enzymes isolated
1.hydroxycobalamine
2. methylcobolamine 3.5-deoxy adenosyl cobolamine.
Clinical Uses:
1- It is essential factor for nutrition of all cells in the body together with folic
acid, it is required for DNA synthesis and regulation
2- Cofactor for many enzymes specially methyl malonyl CoA mutase.
Lack of vit B12 lead to failure of maturation of nucleus with failure of division
of the cells..
The erythroblastic cells in the bone marrow dosenot proliferate normally ,
the cells become larger than normal (megaloblast)
, then macrocytes
,large blood cells released to the peripheral blood.
Deficency of Vit B12
Anemia, Alzheimer, Peripheral Neuropathy, Depression
Pernicious anemia : The term pernicious anemia means
megaloplastic anemia + gastrointestinal symptoms + neurological
symptoms mainly spinal degeneration,
each of those symptoms can occur either alone or along with others.
Pernicious anemia arises when B12 deficiency blocks folic acid
metabolsim lead to functional folate deficiency.
The commonest cause of Pernicious anemia is the malabsorption due to
failure of intrinsic factor.
Intrinsic factor (Small glycoprotein secreated by the parietal cells of
stomach) vitamin b12 absorbed , bound to Intrinsic factor receptor