Vitamin

CONTENT :- VITAMINS

- Introduction Classification Fat Vs Water Soluble Vitamins Water-soluble B-complex vitamins (8 Vitamins)

-Introduction

- Chemistry

- Biochemical function

- Deficiency

- Recommended dietary allowance (RDA)

- Dietary Sources References

VITAMINS“Vitamins are organic compounds required in the diet in small amounts to perform specific biological functions for normal growth and health of an organism”The body needs vitamins to stay healthy and a varied diet usually gives you all the vitamins you need.Vitamins do not provide energy (calories) directly, but they do help regulate energy-producing processes.Vitamins cannot be synthesized by the human body (except D&K) and must be obtained from the diet.

CLASSIFICATION OF VITAMINS

VITAMINS

Water Soluble Fat Soluble

B-Complex Non-B complex

Vit B1 (Thiamine)Vit B2 (Riboflavin)

Vit B3 (Niacin)Vit B5 (Pantothenic acid)

Vit B6 (Pyridoxin)Vit B7 (Biotin)

Vit B9 (Folic Acid)Vit B12 (Cyanocobalamin)

Vit AVit DVit EVit K

Vit C (Ascorbic Acid)

FAT Vs WATER SOLUBLE VITAMINS

FAT SOLUBLE :-

- Dissolve in fat- Need fat for absorption

and transport- Easily stored

WATER SOLUBLE :-

- Dissolve in water

- Easily absorbed and excreted via urine

- Not easily stored

VITAMIN B1(THIAMINE)

Thiamine is a water soluble anti-beri beri vitamin soluble in water

It has specific co-enzyme [TPP – Thiamine Pyrophosphate] which is mostly associated with carbohydrate metabolism

Thiamine is the only natural compound with thiazole ring

CHEMISTRY OF THIAMINE METHELENE BRIDGE THIAZOLE

RING PYRIMIDIN RING

Thiamine contains a pyrimidin ring and a thiazole ring

connected by a methelene bridge.

The alcohol(-OH) group of thiamine is esterified with phosphate(2-molecules) to form the co-enzyme Thiamine pyrophosphate (TPP)

BIOCHEMICAL FUNCTIONS OF TPP TPP act as a Co-enzyme for following enzymes:- - Pyruvate dehydrogenase (pyruvate to Acetyl CoA)

- Transketolase (production of Ribose & NADPH)

- Tryptophanpyrrolase (tryptophan metabolism)

- Pyruvate carboxylase (pyruvate to acetaldehyde)

- TPP binds with the Alfa-ketoacids and transfer the resulting activated carbohydrate group to Alfa-Lipoic acid

- TPP plays an important role in the transmission of nerve impulse. TPP is required for acetylcholine synthesis and the ion translocation of neural tissue

DEFICIENCY

Deficiency of vit-B1 results in a condition called Beri-beri

- Early symptoms are loss of appetite, weakness, constipation, nausea, mental depression etc

RDA :- Adult 1-1.5mg/day Children 0.7-1.2 mg/day

DIETARY SOURCES : - Cereals (Thiamine is mostly concentrated in outer layer), pulses, oil seeds, nuts and yeast are good sources of Vit-B1

VITAMIN B2 (RIBOFLAVIN) Riboflavin through its Co-enzymes (FMN & FAD)

takes part in variety of cellular oxidation-reduction reactions

CHEMISTRY :- Riboflavin contains 6,7-dimethyl isoalloxazine (a heterocyclic 3-ring structure Pyrimidine, Azine, Benzene) attached to D-Ribitol by a nitrogen atom

- Ribitol is an open chain form of sugar ribose with the aldehyde group(-CHO) reduced to Alcohal(CH2OH)

STRUCTURE

Flavokinase ATP ADP FAD synthetase ATP PPi

BIOCHEMICAL FUNCTION OF VITB2

FMN & FAD participate in many redox reactions responsible for energy production

FMN or FAD undergo identical reversible reactions accepting two H-atom forming FMNH2 & FADH2

FAD & FMN are associated in certain enzymes involved in carbohydrate, protein, lipid and purine metabolisms, besides the electron transport chain

Enzymes that use flavin Co-enzymes (FMN/FAD) are called Flavoprotiens

FAD Dependent Enzymes :- Carbohydrate Metabolism:-

- Pyruvate Dehydrogenase (Pyruvate to Acetyl CoA)

- Succinate Dehydrogenase (Succinate to fumarate) Lipid Metabolism:-

- Acyl CoA Dehydrogenase (Acyl CoA to alpha,beta unsaturated Acyl CoA )

Protein metabolism :-

- D-Amino Acid oxidase (D-Amino Acid to alpha keto-acid + NH3)

Purine Metabolism:- Xanthine Oxidase (Xanthine to Uric acid)

DEFICIENCY OF VITB2

It includes cheilosis (fissures at the corner of the mouth) glossitis (tongue smooth and purplish) and dermatitis

RDA :- 1.2-1.7 mg/day for Adult

DIETARY SOURCES :- milk & milk products, meat, eggs, liver, kidney are rich sources

VITAMIN B3 (NIACIN)

Niacin or nicotinic acid is also known as pellagra (Italian:- Rough Skin) preventive factor

The coenzymes of niacin (NAD & NADP) can be synthesized by the essential amino acid, tryptophan.

Structurally it is monocarboxylic acid, the amide form of niacin is known as nicotinamide.

Dietary Niacin & nicotinamide contribute in the synthesis of Co-enzyme NAD (Nicotinamide Adenine Dinucleotide) & NADP

CHEMISTRY OF VIT B3 Nicotinamide

Pyrophosphate

Niacin

Ribose

Adenine

NAD

BIOCHEMICAL FUNCTIONS OF B3

NAD can reversibally reduced to NADH and thus involved in variety of oxidation reduction reactions

Large no of enzymes of class oxidoreductases are dependent on NAD & NADP

These participate in almost all the metabolism (carbohydrate, lipid, protein, nucleic acid)

For Example : - Alcohol dehydrogenase (ethanol to acetaldehyde) Lactate dehydrogenase (pyruvate to lactate) Phenylalanine hydroxylase (phenylalanine to tyrosine)

DEFICIENCY :- Niacin deficiency results in Pellagra.

It involves 3d’s i.e – Dermatitis (rough skin & inflammation of skin), Diarrhoea, Dementia (anxiety, irritability, poor memory, and sleeplessness) if not treated rarely lead to 4th D (Death!)

RDA :- Adult – 15-20mg/day

Children – 10-15 mg/day

DIETARY SOURCES:- liver, yeast, whole grains, cereals, pulses like beans and peanuts are rich sources.

VIT B5(PANTOTHENIC ACID)

Structure-

pantonic acid beta-alanine

pantothenic acid Active form of pantothenic acid is Coenzyme-A and it is largely

bound to proteins Its metabolic role as Coenzyme-A (A for acetylation) is wide

spreadCHEMISTRY:- Pantothenic acid consists of two compounds,

pantonic acid and beta-alanine, held together by a peptide linkage

Coenzyme-A is synthesized from pantothenic acid in a series of reaction.

Coenzyme-A

Coenzyme-A consist of a pantothenic acid joined to thioethanol amine on one end, on the other end pantothenic acid is held by a phosphate bridge to adenylic acid (made up of adenine) & a phosphate linked to carbon-3 of ribose

BIOCHEMICAL FUNCTIONS OF VIT B5 Coenzyme-A is a central molecule involved in all the

metabolism More than 70 enzymes depend on Coenzyme-Ae.g.:- Pyruvate dehydrogenase (pyruvate to Acetyl CoA) - Thiokinase (fatty acid to Acyl CoA) - Pantothenic acid is a constituent of a compound called

Acyl Carrier Protein (ACP) - Activation of certain Amino acids may also involve

CoA-SHDEFICIENCY:- linked to the “burning feet syndrome” – pain

and numbness in the toes, sleeplessness, fatigue etc.RDA :- 5-10 mg/day for adultsDIETARY SOURCES:- egg, liver, meat, yeast, milk etc

VITAMIN B6 Vitamin-B6 is used to collectively represent the

compounds namely Pyridoxine, Pyridoxal, PyridoxamineCHEMISTRY:- Vit-B6 compounds are pyridine derivatives, they differ

from each other in the structure of a functional group attached to 4th carbon in pyridine ring

Pyridoxine is a primary alcohol, pyridoxal is an aldehyde form, while pyridoxamine is an amine form

The active form of Vit-B6 is the Coenzyme Pyridoxal Phosphate (PLP)

PLP can be synthesized from the three compounds Pyridoxine, Pyridoxal, Pyridoxamine

Vit-B6 is excreted in urine as 4-pyridoxic acid

CHEMISTRY OF VIT B6

Diagram remaining

BIOCHEMICAL FUNCTIONS OF VIT B6

PLP is closely associated with the metabolism of aminoacid.

PLP participates in reactions like Transamination, Decaboxylation, Deamination, Transsulfuration etc

E.g.:-Transamination:- Histidine Histamine

Tyrosine Tyramine

Deaminase:- Serine Pyruvate

Threonine alpha-ketobutryic acid

Transsulfurase:- Homocytosin Serine Vit B6 is also involved in transport and absorption of

amino acids

DEFICIENCY

Pyridoxine deficiency is associated with neurological symptoms, such as depression, nervousness, irritability, mental confusion etc

Decrease in hemoglobin level are also associated with Vit-B6 deficiency

RDA :- 2 – 2.2 mg/day for Adults

Dietary Sources :- Animal Sources like egg yolk, fish, milk, meat etc and vegetable sources like cabbage, roots and tubers.

VITAMIN B7(BIOTIN)

Biotin is also known as anti-egg white injury factor,Vit-B7 or Vit-H , it is a sulfur containing B-complex vitamin.

It directly participates as a Coenzyme in the carboxylation(CO2 fixation) reactions (i.e.- carboxylases)

Biotin is 1st converted to carboxybiotin complex by reaction with HCO3 and ATP

CO2-biotin complex is the source of active CO2 which is transferred to substrate.

CHEMISTRY VIT B7

Biotin is a heterocyclic sulfur containing monocarboxylic acid The structure is formed by fusion of imidazole & thiophene rings with a

valeric acid side chain Biotin is covalently bound to amino group of lysine to form biocytin in

the enzyme

O

C

site of CO2 binding HN NH

Imidazole ring HC CH binds with amino grp of Lys in enzyme

Thiophene ring H2C C (CH2)4 COOH

S

BIOTIN

BIOCHEMICAL FUNCTIONS OF VIT B7

Biotin serves as a carrier of CO2 in carboxylation reaction E.g. :- pyruvate carboxylase (pyruvate to oxaloacetate) It is also playing a role in first step of fatty acid

biosynthesis which is carboxylation reaction Acetyl-Co-A carboxylase (Acetyl CoA to Malonyl CoA) Propionyl -Co-A carboxylase (Propionyl -Co-A to methyl-

Malonyl CoA)

DEFICIENCY OF VIT B7

The symptoms of biotin deficiency are anemia, nausea, dermatitis, glossitis etc

The deficiency may be due to prolong use of drugs like sulfonamides or high consumption of raw eggs as it contain avidin which binds with biotin and blocks its absorption from intestine

RDA:- 100 – 300 mg/day for adults Dietary Sources:- liver, kidney, egg-yolk, milk,

tomatoes, grains etc

FOLIC ACID Folic acid is a Hematopoietic vitamin It is important for one-carbon metabolism and is required

for the synthesis of certain amino acids, purines and pyrimidine – thymine

CHEMISTRY:- folic acid consist of three components Pteridine ring, P-amino benzoic acid (PABA), and Glutamic acid (1-7 residues)

The active form of folic acid is TetrahydroFolicAcid (THF) THF is synthesized from folic acid by the enzyme

‘dihydrofolate reductase’

CHEMISTRY OF FOLIC ACID

Tetrahydrofolicacid (THF)

Dihydrofolate reductase

BIOCHEMICAL FUNCTIONS OF FOLIC ACID

Active Coenzyme of folic acid is the reduced tetrahydrofolate (FH4)

This Coenzyme is actively involved in the one carbon metabolism, it serves as an acceptor or donor of one carbon units [formyl (-CHO), methyl(-CH3)] in a variety of reactions involving amino acid and nucleotides metabolism.

NADP NADPH + H+ NAD NADH+ + H+

-CH2OH -CHO -COOH

dehydrogenases H2O

DEFICIENCY OF FOLIC ACID Folic acid deficiency is probably the most common

vitamin deficiency In folic acid deficiency decreased production of

purines is observed which impairs DNA synthesis Folic acid deficiency in pregnant women may cause

neural defects in the fetus, Hence high doses of folic acid are recommended in pregnancy to prevent birth defects

RDA :- 200 microgram per day Dietary Sources :- green vegetables, whole

grains, cereals, liver, kidney, yeast and eggs

VITAMIN B12(CYANOCOBALAMIN) It is also known as anti pernicious anamia vitamin

It is unique vitamin synthesized by microorganisms and not by animals and plants

CHEMISTRY:- The structure of Vit-B12 is complex consists of “corrin

ring” with a central cobalt atom. The corrin ring has four pyrrole units (A,B,C&D), A&D

are directly bound to each other whereas B&C are held by methylene bridges

The groups like methylacetamide & propionamide are the substituent on the pyrrole ring

Cobalt present at the centre of corrin-ring, is bonded to four pyrrole nitrogen's

Cobalt also helds (below the corrin plane), dimethyl benzimidazole (DMB) containing ribose-5-phosphate and amino isopropanol

The cobalt atom also possesses Cyanide(CN) group in cyanocobalamine (Vit-B12)

CHEMISTRY OF VIT B12

Corrin ring system

Directly attached Amino-iso-propanol

Ribose-5-phosphate methelene bridge dimethyl benzimidazole

BIOCHEMICAL FUNCTIONS

Vit-B12 helps in synthesis and maturation of RBC , WBC , & Platelets

Vit-B12 also helps in methylation of homocysteine to methionine, methylation of pyrimidine ring to form thymine

Conversion of ribonucleotides to deoxyribonucleotides.

Conversion of L-methyl malonyl CoA to Succinyl CoA Conversion of glutamic acid to beta-methyl aspartate

DEFICIENCY OF VIT B12

The important disease associated with Vit-B12 deficiency is Pernicious anemia, it is characterized by low Hb-levels, decreased number of RBC and neurological disorders.

RDA:- Adults – 3 microgram/day

Childrens – 0.5-1.5 microgram/day Dietary Sources:- liver, kidney, milk, curd,

eggs, fish, pork, and chiken

References :-

BOOK :- Bio-Chemistry by satyanarayan Website:- www.wikipedia.org

THANK YOU

NON B-COMPLEX VITAMIN VITAMIN C (ASCORBIC ACID) It was the 1st vitamin to be isolated in pure

crystalline form It is a hexose derivative and closely resembles

monosaccharides in structure It is a strong reducing agent The plasma and tissue pre-domintly contain

ascorbic acid in the reduced form Vit-C was named ascorbic acid due to its anti-

scorbutic properties

CHEMISTRY OF VIT C L- ascorbic acid is a strong reducing agent readily

loosing hydrogen atom to become dehydro ascorbic acid.

O C 2H O C H2O O C OH

HO C O C O C

HO C O O C O O C

H C 2H H C H C OH

HO C H OH C H HO C H

CH2OH CH2OH CH2OH

L-ascorbicacid(reduced) dehydroL-ascorbicacid(oxidized) Diketogulonicacid(inactive)

Vit-C activity is lost when the ring dehydro ascorbic acid is hydrolysed to yield diketogulonic acid.

Oxidation of Vit-C is rapid in presence of copper hence it becomes inactive if the foods are prepared in copper vessel.

BIOCHEMICAL FUNCTIONS :- Promotes many metabolic reactionsparticularly protein

metabolism(tyrosine, tryptophan metabolism) Plays an important role in the formation of connective

tissue by synthesizing collagen. As a Coenzyme it may combine with poisons and makes

them harmless untill excreted Vit-C is important for bone and teeth formation Enhances iron absorption by keeping it in ferrous form Enhances the synthesis of immunoglobulins

Vit-A,E&C are important to decrease the risk factor of cataract, cancer and heartattack due to their anti-oxidant(reducing) property

DEFICIENCY:- Absence of ascorbic acid in human diet give rise

to cscurvy, a disease characterized by edema, subcutaneous haemorrhages, anemia and pathological changes in teeth and gums

Many symptoms related to poor connective tissue growth and repair

RDA:- Adult – 60-70 mg/day Sources:- citrus fruits,grminating

seeds,cabbage,cauliflower,beans etc

VITAMIN A The fat soluble Vitamin-A, as such is present only in

foods of animal origin, However,its provitamins carotene are found in plants.

CHEMISTRY:- Retinol and retinal both are isoprenoid compounds

containing six-membered carbocyclic ring and an 11carbon sidechain

RETINOL(Vit-A alcohol):- it is a primary alcohol containing beta-ionons ring.

The side chain has two isoprenoid units, four double bonds and one hydroxyl group

Retinol is present in animal tissues as retinyl ester with long chain fatty acid.

RETINAL (Vit-A aldehyde):- this is an aldehyde form obtained by the oxidation of retinol.

Retinal and retinol are inter convertible RETINOIC ACID (Vit-A acid):- this is produced

by oxidation of retinal However, retinoic acid cannot give rise to the

formation of retinal or retinol BETA-CAROTENE(ProVit-A) this is found in

plant food The carotenes have no inninsic Vit-a activity but

enzymatically they are cleaved into two molecules of retinal

CHEMISTRY OF VITAMIN-A

BIOCHEMICAL FUNCTIONS OF VIT-A Vit-A ia necessary for a variety of functions such as vision, proper growth and differentiation, reproduction and maintenance of epithelial cells.

Vit-A is essential for color and dim-light vision Retinol & retinoic acid function almost like steroid

hormones,they regulate the protein synthesis and thus are involved in the cellgrowth and differentiation

They are also involved in the synthesis of transferrin,the iron transport protein

Cholesterol synthesis requires Vit-A Carotenoids functions as antioxidants and reduce the

risk of cancers initiated by free redicals and strong oxidants

DEFICIENCY The deficiency is mainly related to eyes,skin and growth Night blindness is one of the earliest symptoms,severe

deficiency leads to xerophthalmia(dryness in conjuctiva and cornea and keratinization of epithelial cells)if persist for long time results in the destruction of cornea

RDA:- 1050 mg retinol/day for adult DIETARY SOURCES:- liver,kidney,egg

yolk,milk,cheese,butter,fish(cod or shark) liver oils are very rich in Vit-A, yellow and darkgreen vegetables and fruits are good source of carotenes

VITAMIN-D Vitamin-D resembles sterol in structure and functions like a hormone Most important are Vit-D2(ergocalciferol) & Vit-D3(cholecalciferol)

the form normally found in mammalsCHEMISTRY:- D-Vitamins are generated from the pro-vitamins.ergosterol & 7-

dehydrocholesterol by the action of sunlight Ergosterol occurs in plants and 7-dehydrocholesterol in animals U.V-radiation from sunlight cleaves the beta-ring of both

compounds,both vitamins are of equal potency. 7-dehydrocholesterol in the skin is natural precursor of

cholecalciferol in man. The conversion requires irradiation of skin by sunlight.

Vit-D Preparation available commercially are products of the u.v.irradiation of ergosterol from yeast

FORMATION OF VIT-D

BIOCHEMICAL FUNCTIONS OF VIT-D calcitriol regulates the plasma level of calcium&phosphate,it act at 3-different level(intestine,kidney and bone)

Action on intestine:- it binds with cytosolic receptor and increase the intestinal absorption of calcium and phosphate

Action on bone:- it stimulates calcium uptake for deposition as calcium phosphate, Thus essential for bone formation.

Action on kidney:- it minimizes the excretion of calcium and phosphate.

DEFICIENCY OF VIT D Deficiency of Vit-D leads to demineralization of

bone This results in rickets(bone deformities and soft

bone) in children

RDA :- 5mg cholecalciferol per day

Dietary Sources :- fatty fish,fish liver oils, egg yolk.

VITAMIN-E(TOCOPHEROLS) Tocopherols occurs in plant oils in varying amounts Vit-

E is naturally occurring antioxidant. It is essential for normal reproduction in many animals

hence known as anti-sterility vitamin

CHEMISTRY:- Vit-E is the name given to a group of tocopherols,

possessing Vit-A activity Alpha- tocopherol is the most active The tocopherol are derivatives of 6-hydroxy

chromane(tocol) ring with isoprenoid(3units) sidechain. The antioxidant property is due to the chromane ring.

CHEMISTRY VIT-E

BIOCHEMICAL FUNCTIONS VIT-E It prevents the non-enzymatic oxidation of various cell

component (e.g. unsaturated fatty acids)by molecular oxygen and free radicals(superoxide,hydrogen peroxide)

Vit-E is essential for membrane structure and integrity of the cell as it is found in association with lipoprotein

It protects RBC’s from haemolysis by oxidizing agents Vit-E preserves and maintains germinal epithelium of

gonads for proper reproductive function It is required for optimum absorption of amino acids

from intestine It is required for proper storage of creatine in skeletal

muscles

DEFICIENCY OF VIT E Vit-E deficiency may cause sterility,megaloblastic

anaemia and changes in central nervous system, increased fragility of erythrocytes,abnormal cellular mambrane etc

RDA :- 10mg of alpha-tocopherol/day for Adult

Dietary Sources :- cotton seed oil, peanut oil, corn oil, sunflower oil etc are good sources, also present in meat,milk, butter and eggs

VITAMIN K Vitamin-K is the only fat soluble Vitamin with a specific

Coenzyme function. It is required for the production of blood clotting factor,

essential for coagulation

CHEMISTRY:- Vit-K exists in different forms,Vit-K1 (phylloquinone) is

present in plants Vit-K2(menaquinone) is produced by intestinal bacteria

and also found in animals Vit-K3(menadione)is a synthetic form All three Vitamins are naphthoquinone derivatives Isoprenoid side chain is present in Vitamins-K1 & K2

CHEMISTRY OF VIT-K

Vit-K2 (menaquinone)

Vit-K3 (menadione)

BIOCHEMICAL FUNCTION VIT-K

Vit-K has been shown to be involved in the maintenance of normal levels of blood clotting factors(2,7,9,10) all of which are synthesized in liver

Vit-K is also required for the carboxylation of glutamic acid residues of osteocalcin, a calcium binding protein in the bone

Plays an important role in blood clotting

DEFICIENCY VIT-K Leads to lack of active prothrombin in the

circulation, blood coagulation is adversely affected and blood clotting time is increased

RDA :-70-140 microgram per day for adult

Dietary Sources:- cabbage,cauliflower,tomatoes,spinach and other green vegitables are good sources

BIOCHEMICAL FUNCTIONS OF VIT-A