vitamin B1, B2, B12 physiological characters and chemistry

1. ISF COLLEGE OF PHARMACY
VITAMINS
THAKUR KARANVIR SINGH
M.PHARMACY
(PHARMACEUTICAL CHEMISTRY)

2. Definition of vitamin
Any of a group of
organic compounds
which are essential for
normal growth and
nutrition and are required
in small quantities in the
diet because they cannot
be synthesized by the
body.

3. Chemistry & physiological
significance of vitamins

4. Vitamin B1 (Thiamin)
 Vitamin B1, thiamin, or
thiamine enables the body
to use carbohydrates as
energy.
 It is essential for glucose
metabolism, and it plays a
key role in nerve, muscle,
and heart function.
 Vitamin B1 is a water-
soluble vitamin, as are all
vitamins of the B complex.

5. DIETARY SOURCES
• Cereals
• Pulses
• Oil seeds
• Nuts
• Yeast
 Also present in
• Pork
• Liver
• Heart
• Milk
• kidney

6. DEFICENCY SYMPTOMS
• Beri-beri
• Loss of appetite (anorexia)
• Weakness
• Constipation
• Nausea
• Mental depression
• Peripheral neuropathy

7. Chemistry of vitamin B1

8.  Thiamine or vitamin B1 named as the "thio-vitamine"
("sulfur-containing vitamin") is a water-soluble of the B
complex.
 It is water soluble vitamin.
 It is anti beri-beri vitamin.
 It has specific coenzyme Thiamine pyrophosphate (TPP)
which is mostly associated with carbohydrates
metabolism.
 In 1936 williams and his associates determines the
structure of Thiamine.
 Thiamine contain pyrimidine ring Thiazole ring held by
methylene bridge.
 Thiamine is only natural compound which having
thiazole ring.
 Alcohol group of thiamine esterified with phosphate

9. • The conversion of thiamine to its coenzyme form is
carried out by the enzyme thiamine diphosphokinase,
with adenosine triphosphate (ATP) as the
pyrophosphate (PP) donor.

10. Physiological significance of
vitamin B1
 The active from of vitamin B1 in the body is
thiamin pyrophosphate (TPP) which along with
lipoic acid acts as a prosthetic group for
carboxylases.
 Thiamine pyrophosphate is formed by the
esterification of alcoholic group of thiamine
with phosphate.
 TPP transferase catalyzes the transfer of
pyrophosphate group from ATP tothiamine.

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12. The coenzyme, thiamine pyrophosphate or cocarboxylase is intimately
connected with the energy releasing reactions in the carbohydrate
metabolism
1. The enzyme pyruvate dehydrogenase catalyses (oxidative
decarboxylation) the irreversible conversion of pyruvate to acetyl CoA.
This reaction is dependent on TPP.
2. D-Ketoglutarate dehydrogenase is an enzyme of the citric acid cycle.
This enzyme is comparable with pyruvate dehydrogenase and requires
TPP.
3. Transketolase is dependent on TPP. This is an enzyme of the hexose
monophosphate shunt (HMP shunt).
4. The branched chain D-keto acid dehydrogenase (decarboxylase)
catalyses the oxidative decarboxylation of branched chain amino acids
(valine, leucine and isoleucine) to the respective keto acids. This
enzyme also requires TPP.
5. TPP plays an important role in the transmission of nerve impulse. It is
believed that TPP is required for acetylcholine synthesis and the ion
translocation of neural tissue

13. Reaction dependent on thiamine
pyrophosphate

14. Vitamin B2 (Riboflavin)
 Riboflavin is a B vitamin.
 Riboflavin is necessary
for growth and for the
production of red
blood cells.
 Riboflavin also plays
an important role in
how our bodies gets
energy from
carbohydrates, fats, and
proteins.

15. DIETARY SOURCES
• Milk and milk products
• Meat
• Eggs
• Liver
• Kidney
Comparatively less obtained
 Cereals
 Fruits
 Vegetables
 fish

16. DEFICIENCY SYMPTOMS
• Cheilosis (fissures at the corners of mouth)
• Glossitis (tongue smooth and purplish)
• Dermatitis.
• It is mostly seen with other vitamin deficiencies.
Chronic alcoholics are susceptible to B2 deficiency

17. Chemistry of vitamin B2

18.  It is water soluble vitamin.
 It aids in the metabolism your fats, carbohydrates,
protein and ketone bodies.
 It is also important for your energy
metabolism

19. • Riboflavin contains 6,7-dimethyl isoalloxazine (a
heterocyclic 3 ring structure) attached to D-ribitol by
a nitrogen atom (9th position) sugar alcohol called
ribitoyal group is attached.
• Ribitol is an open chain form of sugar ribose with the
aldehyde group (CHO) reduced to alcohol (CH2OH).
• Riboflavin is stable to heat but sensitive to light.
• When exposed to ultra-violet rays of sunlight, it is
converted to lumiflavin which exhibits yellow
fluorescence.
• The substances namely lactoflavin (from milk),
hepatoflavin (from liver) and ovoflavin (from eggs)
which were originally thought to be different are
structurally identical to riboflavin.

20. Physiological significance of
vitamin B2
 Riboflavin is the component of two flavin
enzymes
The flavin mononucleotide (FMN)
The flavin adenine dinucleotide
 Both these flavin enzymes take part in various
oxidation-reduction reactions.
 The oxidized flavines are yellow in colour while
upon reduction ( one hydrogen atom at 1 and other
at 10 positions acquisition occurs ) and they become
colourless.

21. The reaction can also proceed in the reverse
direction.
Hydrogen addition
occurs in 2 steps
-

22. Structure and biosynthesis of
flavin mononucleotide (FMN)
and flavin adenine
dinucleotide (FAD)

23.  Both the coenzymes function with a group of
proteins known as the flavoproteins.
 These flavoproteins due to their diverse nature
can act as oxidases, dehydrogenases,
hydroxylases ,oxidative decorboxylases.
 Riboflavin or vitamin B2 is an essential nutrient in
human nutrition and plays a key role in the
production of energy.
 Vitamin B2 is needed to process amino acids and
fats, activate and folic acid, and help convert
carbohydrates into the fuel the body runs on.

24.  Vitamin B2 can act as an antioxidant.
 Vitamin B2 is an intermediary the transfer of
electrons in the cellular oxidation-reduction
reactions which generate energy from protein,
carbohydrate and fat.

25. Vitamin B12
 Vitamin B12 does
a lot of things for
your body.
 It helps make your
DNA and your
red blood cells.
 B12 is the most
chemically
complex of all the
vitamins

26. DIETARY SOURCES
• Food and animal are the only origin sources for vitamin B12
• Liver
• Kidney
• Milk
• Curd
• Eggs
• Fish
• Pork
• Chicken
• Curd is better source than milk, due to the synthesis of B12 by
LACTOBACILLUS
• Vitamin B12 is synthesised only by microorganisms (anaerobic Bacteria)
plants cannot synthesize
• B12 is never found in plant foods
• Animals obtain B12 either by eating foods, derived from other animals or
from the intestinal bacterial synthesis

27. DEFICENCY SYMPTOMS
• The most important disease associated with
vitamin B12 deficiency is pernicious anemia. It is
characterized by low hemoglobin levels, decreased
number of erythrocytes and neurological
manifestations
• B12 deficiency is also associated with neuronal
degeneration and demyelination of nervous
system.

28. Chemistry of vitamin B12

29.  Vitamin B12 is the only naturally occurring
organic compound which contains cobalt
(35%).
 It is water soluble, deep red, tasteless, crystalline
compound with a molecular weight of 1355 and is
hence stable at neutral pH but not at alkaline pH.

30.  The salient features of the structure of Vitamin B12 are given
below:
1. There are many closely related compounds having B12
activity. All are cobalamins and contain in their molecules a
portion called corrin ring which to a large extent resembles
the tetrapyrrole ring structure of porphyrins.
2. A single cobalt atom having one positive charge is present in
the center of this ring. The Co atom is attached to all the four
N atoms of corrin ring in the same way as Fe++ is attached to
5,6, dimethylbenzimidazole ribose which is attached to the
side chain on ring IV through Phosphate and aminopropanol.
3. The positive charge on Co atom is balanced by one of the
several groups which give rise to more than one type of
vitamin B12. These different types of vitamin B12 are given
below along with their characteristic groups attached to the
Co atom
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31.  B12: Cyanocobalamin: It has CN. It is the commonly used
form of the vitamin B12
 B12-a : hydroxocobalamin: It has OH. It is claimed to be
retained in the body
 B12-b : aquocobalamin: It has H2O
 B12-c: nitrocobalamin: It has NO2

32. Role of vitamin B12 in
isomerization of methyl
malonyl CoA to succinyl
CoA

33. Physiological significance of
vitamin B12
 1. Supports Energy
Vitamin B12 plays a key role in how your body creates energy. It
keeps your cells fed, happy, and healthy. Without it, your cells get
hungry and you feel weak, tired, and like you’re dragging all the
time. The nutrient releases energy into the cell and provides you
with the appropriate balance you need for thinking and moving
throughout your day.
 2. Protects the Heart
Your heart and entire cardiovascular system needs B12. One of its
jobs is to remove a dangerous protein called homocysteine from the
blood. If homocysteine is allowed to roam through blood, it
damages your arteries leading
to inflammation and heart disease. Get enough B12 and you’ll
keep homocysteine levels down and your heart happy.

34.  3. Your Bones Need It
Studies have found patients with osteoporosis have higher levels
of homocysteine and low levels of B12 than people with strong,
healthy bones.Could B12 be a viable adjunct to future
osteoporosis approache. If you suffer from osteoporosis or similar
bone issues, speak to your doctor about getting your vitamin B12
levels tested.
 4. Prevents Nerve Damage
Your nerves have a protective covering to keep them safe from
toxins and free radicals in your blood.
Without these coverings, called myelin sheaths, exposed nerves
get damaged and may even die. These dead nerves disrupt
signals to and from the brain and may play a role in nerve-
related conditions. Vitamin B12 supports the way your body.
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35.  5. Protects Brain Health
Researchers have noted Alzheimer’s patients have much lower levels
of B12 than those of a similar age who have sharp, clear memory. In
the same way B12 helps protect nerve cells, it helps protect the myelin
sheaths of brain cells that are often lacking in Alzheimer’s patients.
Some research suggests that cobalamin deficiency may cause a type of
dementia in elderly patients that is in fact reversible with the right
nutritional intervention.
 6. Keeps You Looking and Feeling Young
Aging happens when your cells begin to wear and tear, and they age
faster when your DNA doesn’t replicate correctly.
Many factors can affect DNA replication, like free radicals, toxins in
the blood, high blood sugar, and high levels of omega-6 fats in your
diet. B12 supports DNA health, thereby keeping your cells younger.
And when your cells are young, you look and feel young too.
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36. About ten enzymes requiring vitamin B12 have been identified. Most
of them are found in bacteria (glutamate mutase, ribonucleotide
reductase etc.). There are only two reactions in mammals that are
dependent on vitamin B12.
1. Synthesis of methionine from homocysteine : Vitamin B12, as
methylcobalamin is used in this reaction. This is an important
reaction involving N5-methyl tetrahydrofolate from which
tetrahydrofolate is liberated (enzyme-homocysteine
methyltransferase or methionine synthase). This metabolic step
signifies the interrelation between vitamin B12 and folic acid
2. Isomerization of methymalonyl CoA to succinyl CoA : The
degradation of odd chain fatty acids, certain amino acids (valine,
isoleucine etc.) and pyrimidines (thymine and uracil) produce
directly or through the mediation of propionyl CoA, an important
compound methylmalonyl CoA. This is converted by the enzyme
methylmalonyl CoA mutase to succinyl CoA in the presence of B12
coenzyme, deoxyadenosyl cobalamin. This reaction involves
hydrogen transfer and intramolecular rearrangement. In B12
deficiency, methylmalonyl CoA accumulates and is excreted in urine
as methylmalonic acid.

37. References
B2,chemistry Of Vitamin B2,physiological Importance,synthesis Of
Riboflavin,reactions, Vitamin B2 Deficiency Symptoms,functions,uses Of
Riboflavin.
5.
4. By Dr. Edward Group Dc, Np, Dacbn, Dcbcn, Dabfm
Published On March 19, 2015, Last Updated On April 24, 2017
Michael B. Davies, John Austin, David A. Partridge: Vitamin C- Its Chemistry
And Biochemistry
6. Dr. P.Ravisankar M. Pharm.,Ph.D
1. Feeding And Nutrition Of Companion And Hobby Animals, János, Tossenberger
(2011) , Kaposvar University
2. Vitamin B1 [Thiamine] Medicinal Chemistry By P.Ravisankar [Source]
3. Vitaminb2[riboflavin] Medicinal Chemistry, by P.Ravisankar [Sources Of Vitamin