Vitamins are organic substances that are essential in small amounts for fundamental body functions. There are different types of vitamins that can be divided into fat-soluble and water-soluble categories. Vitamin A plays important roles in vision, growth, immune function, and cellular differentiation. A deficiency can lead to night blindness and other vision problems.

1. VITAMINS are organic
substances , essential in the diet
in small amounts that are involved
in fundamental functions of the
body.
Fat soluble vitamins
Vitamin - A

2. Vitamin K (intestinal flora micro-
Organisms in intestine.
Vitamin D is synthesized by irradiation (UV light) of 7-dehydro cholesterol
(ergosterols) in the skin.
Biotin is synthesized by bacteria in the large intestine.(or) obtained from
food.

3. VITAMINS
INTRODUCTION
Defination: A vitamin is an organic compound required as a nutrient in tiny
amounts for the maintenance and growth of an living organism.
In the early 20th century the discovery of vitamins began.
Each and every living animal needs vitamins to grow and be healthy.
Since the human body can ‘t produce vitamins naturally or normally produce the
amounts needed, food provides the body with them.
There are different vitamins found in different foods. These vitamins give vital
nutrients to an animal..
Vitamins deficiency may lead to certain specific diseases or symptoms which
can be cured by the administration of that specific vitamin only.
The term vitamin was first discovered by Funk.
He coined the term "vitamine," a combination word from vita and amine, meaning
amine of life.
At the time they were considered to be amines that are vital for the life.
How ever it was later found that not all vitamins were “nitrogen” or amines.
After researchers began to suspect that not all "vitamines" had an amine
component. (particularly vitamin A)
In 1920, Drummond proposed that the final "e" be dropped.That’s why in the
word Vitamines “e” is removed and called vitamins.

4. • In 1906, the British biochemist Sir. Frederick Hopkins demonstrated that
foods contain accessory factors in addition to proteins, carbohydrates, fats,
minerals and water.
• Funk identified that the antiberiberi substance in unpolished rice was
an amine (a type of Nitrogen-containing compound), so Funk
proposed that it be named vitamine, from vital amine. It was later
discovered that different vitamins have different chemical properties.
This discovery caused vitamine to be turned into vitamin.
• 1912 Hopkins and Funk made a hypothesis. The hypothesis stated the
absence of some vitamins could cause diseases such as beriberi and scurvy.
Later a letter was assigned to each vitamin.
• The letters which were assigned to vitamins in the early years of
vitamin research categorize them according to their functions.
• Later the names were given to vitamines based on their order of discovery.
• Butter can be important because it is a source of Vitamin A.
The pigments that are converted into Vitamin A, are found in
most fruits and vegetables. Vitamin A is important because it
can prevent diseases.

5. • Cereal and seeds can be important because of its source of
Vitamin B. Vitamin B is important because it can prevent beriberi.
• Citrus Fruits can be important because of their source of vitamin C.
Vitamin C is important for strength and metabolism.
• Milk can be important because it is a source of vitamin D. Vitamin D is
important because it is essential for bone growth.
• Plants can be important because of the plant oil which is a source
of Vitamin E. Vitamin e is important because it is a source of
oxidation in body tissues.
• Sub groups of these vitamins were
disignated using subscripts 1,2,3,4,5 etc.
• Ex:- VitaminB1,B2,B3,B6,B12; VitaminD2,D3,
VitaminK1,K3.

6. • The value of eating a certain food to maintain health was recognized
long before vitamins were identified. The ancient Egyptians knew that
feeding liver to a patient would help cure night blindness, an illness
now known to be caused by a vitamin A deficiency.
The Ancient Egyptians knew that feeding a patient liver
would help cure night blindness.

7. Fruits and vegetables are often a good source of many vitamins.
Since the human body can‘t produce vitamins naturally or normally produce the
amounts needed, food provides the body with them. There are different vitamins
found in different foods. These vitamins give vital nutrients to an animal.

8. • The Japanese navy, he experimented using crews of two battle
ships; one crew was fed only white rice, while the other was fed
a diet of meat, fish, barley, rice, and beans. The group that ate
only white rice documented 161 crew members with beriberi
and 25 deaths, while the latter group had only 14 cases of
beriberi and no deaths. This convinced Takaki and the
Japanese Navy that diet was the cause of beriberi, but
mistakenly believed that sufficient amounts of protein prevented
it.
• Feeding unpolished rice instead of the polished variety to
chickens helped to prevent beriberi in the chickens.
• Frederick Hopkins postulated that some foods contained
"accessory factors"—in addition to proteins, carbohydrates,
fats, that were necessary for the functions of the human body.
• Hopkins and Eijkman were awarded the Nobel Prize for
Physiology or Medicine in 1929 for their discovery of several
vitamins.

9. • In humans
• Vitamins are classified as either water-soluble or fat soluble.
• In humans there are 13 vitamins:
• 4 fat-soluble (A, D, E and K)
• 9 water-soluble (8 B vitamins and vitamin C). Water-soluble
vitamins dissolve easily in water and in general, are readily
excreted from the body, to the degree that urinary output is a
strong predictor of vitamin consumption
• Because they are not readily stored, consistent daily intake is
importantMany types of water-soluble vitamins are synthesized
by bacteria.
• Fat-soluble vitamins are absorbed through the intestinal tract
with the help of lipids (fats). Because they are more likely to
accumulate in the body, they are more likely to lead to
hypervitaminosis than are water-soluble vitamins.
• Fat-soluble vitamin regulation is of particular significance in
cystic fibrosis

12. Fat soluble vitamins
• Vitamins A, D, K and E are the fat-soluble vitamins.
• These vitamins are soluble mainly in lipids
or oil and hence called fat soluble vitamins.
• excessive use of fat soluble vitamins may lead to their
accumulation in the body (hypervitaminosis) due to
delayed elimination rate. This accumulation of vitamins
results in toxic effects.
• fat soluble vitamin tend to be stored in fatty tissues
(adipose tissue) of the body and in the liver.
• They are eliminated slowly from the body because of
their lipophilic character.

14. • Fat soluble vitamins Basic structural moiety.
vitamin A Diterpenoid
Vitamin D Steroidal moeity.
Vitamin E Chromane ring system
with an isoprenoid side
chain.
Vitmin K Napthaquinone derivative
BASIC STRUCTURAL MOIETY OF FAT SOLUBLE VITAMINS

16. The biological and IUPAC name of
vitamin A is Retinol.
• Vitamin is also known as
Axerophthol because
it is used in the treatment of
Xerophthalmia
(Drying and thickening of
conjunctiva).
• The structure of vitamin A
constitute a β-ionone ring.
• Vitamin A contains 5 conjugated double
bonds which are key to some biological
actions.
• Isolated in impure form by McCollum in
1915.

17. Animal Foods Plant Foods
Cod liver oil Sweet potato
Liver & kidney Carrots
Egg Cantaloupe
Butter Spinach
Milk & cheese Apricot
Fish & meet Papaya
RICH DIETARY SOURCESRICH DIETARY SOURCES

18. Vitamin A
• Exits in 3 forms:
• all trans-retinol
• long chain fatty acyl ester of retinol (main
storage form)
• retinal (the active form in the retina)
• retinoic acid is also considered to be
physiologically active
• provitamin A or carotene can be
converted to retinol in vivo

19. Vitamin A
Chemical nature and properties
﹡natural form ： A1 （ retinol ）
A2 （ 3-dehydro-retinol ）
﹡active form ： retinol 、 retinal 、 retinoic acid
﹡pro-vitamin A ： β-carotene
﹡storage : liver,adipose tissue of the body.

21. CH3
CH3H3C
CH3
CH2OH
CH3
VITAMIN A (RETINOL)RDA: 0.7 mg
Chemistry of vitamin A.
•Vitamin A (Retinol) is a cyclic polyene alcohol which resembles the
structure of Diterpenoid.
•The structre of vitamin A constiture of a β- ionone ring.
• four conjugated double bonds in the side chain of vitaminA.
•They are in trans arrangement.
•Synthetic retinol is a trans isomer. It exists in 8 stereoisomeric
forms.
•β- ionone ring and conjugated double bonds are essential for the
biological activity of vitaminA.
General structure of
β- ionone ring.
CH3
CH3H3C
CH3
CH2OH
CH3
VITAMIN A (RETINOL)

22. The Retinoids
• 3 forms of vitamin A
important for health
– Retinal
– Retinoic acid
– Retinol (key player; can
be converted to other
forms)
• β-carotene (a
carotenoid or pigment)
in yellow/orange foods
is a potent provitamin A

23. Terminal Ends of Retinoids
CH3
CH3H3C
CH3
CH2OH
CH3
VITAMIN A (RETINOL)
β-ionone ring.
β-carotine
(some)
Beta-carotene (most)
(retinyl
esters)

24. 5 “W”
2 “W”, 1”V”
(which is abundantly found in carrots)
(intestinal mucosa)
(2 molecules of vitaminA aldehyde)
(VitaminA)
(Reduction)
(tretinoin)
Conversion of carotenoids to Retinoids

29. Role of Vitamin A in Vision
Visual Pigment

30. The Eye is a camera
• Retina is the innermost photosensitive layer of the eye
composed of nerve cells called rods and cones.
• Rhodopsin(photosensitive pigment) is formed form a
protein called Opsin and cis-isomer of Retinal
i.e.vitaminA aldehyde.
The Role of Vitamin A in vision:

31. The Retina
Cross-section of eye
Ganglion cell layer
Bipolar cell layer
Receptor layer
Pigmented
epithelium
Ganglion axons
Cross section of retina

32. Retina up-close
Light

33. © Stephen E. Palmer, 2002
Cones
cone-shaped
less sensitive
operate in high light
color vision
Two types of light-sensitive receptors
cone
rod
Rods
rod-shaped
highly sensitive
operate at night
gray-scale vision photoreception is the function of 2
specialized cell types: rods and cones
both types of cells contain a photosensitive
compound called opsin
in rod cells opsin is called scotopsin
and the receptor is called rhodopsin or
Visual purple.

34. The Visual Cycle
(Rods and cones
Contains opsin
Which is photo
Sensitive pigment)
(vitamin A
aldehyde)
Activation of rhodopsin by
Light rays leads to genaration
Of transmission of impulse
Through the optic nerves.
is formed from a
Protein pigment
Opsin +11-cis
Retinal.
+
(Retinol is carried from the liver (storage site) to retina by means of carrier proteins called
Retinolbinding proteins(RBP) by forming complex (RBP_retinol complex)this complex
Dissociates in the retina and gets deposited in the pigmented epithelial cells of the inner

35. Physiological Role
As previously mentioned vitamin A is essential to vision. Within the photoreceptor cells of the retina are
the rods, which detect small amounts of light and are specialized for motion detection and vision in dim
light.
The cones that are specialized for color vision in bright light .
Both rods and cones posses specialized outer segment disks that contain high amounts of rhodopsin
and iodopsin respectively.
These compounds are often referred to as the "visual pigment"
Photoreceptor cells detect light and undergo a series of reactions, which send signals to the brain,
where they are deciphered as a particular visual image.
 A second very important function of vitamin A involves retinoic acid. Acting as a hormone, retinoic acid
first binds to retinoic acid receptors. The receptors then interact with specific nucleotide sequences of
DNA. The interaction directly affects gene expression and transcription, which in turn control cellular
development and body processes.
For example, epithelial cells depend on retinoic acid for structural and functional maintenance. This
role of vitamin A is important for growth mechanisms in a manner that is not completely understood.
 Retinoic acid is especially important in heart, eye, lung and ear development.
The development of gap junctions between cells is also affected by retinoic acid.
Besides the previously mentioned functions, vitamin A plays a role in numerous other processes.
Vitamin A is thought to play a key role in glycoprotein synthesis.
. Once formed, glycoproteins are important in multiple cellular processes including: communication,
recognition, adhesion, and aggregation. Reproductive processes, bone development, along with
maintenance, and immune system function are dependent upon different isoforms of vitamin A.
 Retinoids are most commonly used in the treatment of skin diseases. The role the retinoids play in
epithelial cell formation is very important in the treatment of skin cancer, acne, and acne-related diseases
Vitamin A also has antioxidant properties. However, beta-carotene has been noted as having pro-
oxidant properties.
Despite these discrepancies vitamin A is known to help repair damaged tissue and therefore may be
beneficial in counter-acting free radical damage.

36. Physiological Role/ Importance of Vitamin A
Vitamin A is needed for the various functions of
the body like…..
• Vision
• Growth and differentiation of epithelial cells.
• Reproduction and embryonic development.
• Maintenance of epithelial cells.
• Maintence of immune system.
• β-carotine acts as an antioxidant and thus decreases the risk of
cancers.
• Retinol and retinoic acid are involved in the regulation of the protein
synthesis,which inturn is involved in cell differentiation and growth.
• Maintenance of healthy epithelial tissue because it prevents keratin
synthesis.
• Retinyl phosphate is required for the production of
mucopolysaccharides.
• Vitamin A is involved in the synthesis of transferrin ( iron transport
protein)

37. Uses of Vitamin A.
1. Vitamin A is mainly used in the treatment of
treatment of deficiency of Vitamin A.
2. It is also used in the treatment of …
Dermatological disease and lesions.
- Xerophthalmia.
- Cold,warts,corns and calluses( skin infections
- Acne
- Hyperkeratosis of arms.

38. Carotenoids
• Additional physiologic
effects beyond vitamin A
– Serving as an “antioxidant”
• Remove excess “electrons”
from cell system
• Electrons (free radicals)
damage cells and DNA
– Can cause mutations
– Protecting from cancer
(related to antioxidant
function?)
– Protecting from heart
disease?
– Supports immune system
function

39. Functions of Vitamin A:
Growth and Differentiation of Cells
• Retinoic acid is necessary for cellular
differentiation
• Important for embryo development, gene
expression
• Retinoic acid influences production,
structure, and function of epithelial cells
that line the outside (skin) and external
passages (mucus forming cells) within the
body

40. Functions of Vitamin A:
Immunity
• Deficiency leads to decreased resistance
to infections
• Supplementation may decrease severity
of infections in deficient person

41. Vitamin A Analogs for Acne
• Topical treatment (Retin-A)
– Causes irritation, followed by peeling of skin
– Antibacterial effects
• Oral treatment
– Regulates development of skin cells
– Caution regarding birth defects

42. Possible Carotenoid Functions
• Prevention of cardiovascular disease
– Antioxidant capabilities
– ≥5 servings/day of fruits and vegetables
• Cancer prevention
– Antioxidant capabilities
– Lung, oral, and prostate cancers
– Studies indicate that vitamin A-containing foods
are more protective than supplements
• Age-related macular degeneration
• Cataracts
• In general, foods rich in vitamin A and other
phytochemicals are advised rather than
supplements

43. Deficiency of Vitamin A
• Most susceptible
populations:
– Preschool children
with low F&V intake
– Urban poor
– Older adults
– Alcoholism
– Liver disease (limits
storage)
– Fat malabsorption
• Consequences:
– Night blindness
– Decreased mucus
production
– Decreased immunity
– Bacterial invasion of
the eye
– Conjunctival xerosis
– Bitot’s spots
– Xerophthalmia
– Irreversible blindness
– Follicular
hyperkeratosis
– Poor growth

44. • Diseases of deficiency:
– Nigh blindness and xerophthalmia (dry eye)
– Skin disorders
– Lack of growth
• Hypervitaminosis:
– A serious potential problem (CNS disorders;
birth defects)

45. Upper Level for Vitamin A
• 3000 μg retinol
• Hypervitaminosis A results from long-
term supplement use (2 – 4 x RDA)
• Toxicity
• Fatal dose (12 g)

46. Toxicity of Vitamin A
–Acute – short-term megadose
symptoms disappear when intake stops
• GI effects
• Headaches
• Blurred vision
• Poor muscle coordination

47. Toxicity of Vitamin A
–Chronic – long-term megadose;
possible permanent damage
• Bone and muscle pain
• Loss of appetite
• Skin disorders
• Headache
• Dry skin
• Hair loss
• Increased liver size
• Vomiting

48. Toxicity of Vitamin A
• Teratogenic (may occur with as little as 3 x
RDA of preformed vitamin A)
– Tends to produce physical defect on
developing fetus as a result of excess vitamin
A intake
– Spontaneous abortion
– Birth defects

49. Health Effects of Vitamin A

50. Toxicity of Carotenoids
• Not likely, as rate of conversion of
carotenoids to retinoic acid by liver is slow
and efficiency of absorption of carotenoids
decreases as intake increases
• Hypercarotenemia
– High amounts of carotenoids in the bloodstream
– Excessive consumption of carrots/squash/beta-
carotene supplements
– Skin turns a yellow-orange color

51. Vitamin A analogues:
Tretinoin
1. Tretinoin is also called retinoic
acid or Vitamin A acid.
2. Tretinoin is obtained by the
oxidation of retinal(vitamin A
aldehyde).
3. Tretinoin was considered to be
a form of vitaminA that acts
mainly on the skin, hence it is
used in the treatment of
dermatological diseases.
5. IUPAC name of tretinoin is
retinoic acid.
(Retinoic acid) (Or) VitaminA acid.
CH3
CH3H3C
CH3
CH2OH
CH3
VITAMIN A (RETINOL)
COOH
Tretinoin (Retinoic acid)

53. • Physico-chemical properties:
Tretinoin is yellow to light –orange crystalline powder,insoluble in water and
slightly soluble in alcohol and chloroform.
It is unstable to heat,light and air. M.P= 176-181o
C.
Physiological role/importance of tretinoin:
Tretinoin is genarally for maintenance of cell membrane,protein synthesis
and formation of skeletal muscle.
It is involved in the cell differentiation and cell growth along with Vitamin A.
It is involved in the synthesis of transferrin(iron transport protein)
Adverse/toxic effects:
Hyperpigmentation or Hypopigmentation may occur when exposed to sunlight.
(it is temporary effect which may be reversible)
When applied to exzematous skin it causes severe irritation.
Topical application some times leads to irritation,peeling,crusting,blistering of
skin.

54. Uses of tretinoin:
Tretinoin is used mainly in the treatment of
• skin diseases.
• Acne vulgaris.
• In the treatment of Hyperkeratotic conditions.
• Solar and follicular keratosis(red spots with scaly
surface)
• Lamellar ichthyosis(thickening of skin on plam and soles)
• Hyperplastic dermatosis.
• It acts as antioxidant and freeradical scavenger,which
protects the skin form radiation effects.This property is
useful in the treatment of somcancers,carcinogenesis(due
to radiation and carcinogens).

55. Isotretinoin(Accutane)
• Isotretinoin is a cis-isomer of retinoic
acid(tretinoin).
• The configuration of double bond at α and β
carbon atoms is cis.
Mechanism of action:
Isotretinoin acts by inhibiting the function of
sabaceous galnds and follicular
keratinization,thus it decreases the production
of sebum,size and differentiation of the
sebaceous glands.

56. CH3
CH3H3C
CH3 CH3
COOH
ISOTRETINOIN (ACCUTANE)
Used in the treatment of severe acne

57. • Physico-chemical properties:
It is yellow-orange to orange,crstallin
powder,sparingly soluble in alcohol and
insoluble in water.
Toxic effects:
Chronic hypervitaminosisA, facial dermatitis,thin
and dry hair,fragile and dryskin,drymouth
andeyes,conjunctivitis(inflammation of
conjunctiva),inflammation of chips,inflammation
of urethra,peeling of skin on
palms,soles,jointpains and excessive

58. Uses of isotretinoin
• Isotretinoin is mainly used in the treatment
of Recalcitrant cystic Acne.( acne in which
predominant lesions are cysts and deep
seated scars).