This document summarizes several fat-soluble vitamins: Vitamin A was discovered in the early 1900s when rats fed casein and starch-based diets failed to grow. It was later isolated from foods and named vitamin A. Retinol is the usable form found in animal foods that can be converted to retinal and retinoic acid in the body. Plants contain carotenoids like beta-carotene that form vitamin A. Vitamin D is synthesized in the skin upon exposure to sunlight and helps with calcium absorption and rickets prevention. The liver and kidney metabolize vitamin D forms including cholecalciferol and ergocalciferol. Vitamin E was

1. MSCDFSM BIOCHEMISTRY
VITAMIN II

2. FAT SOLUBLE VITAMIN :
VITAMIN A
• 1906 -1912 , Hopkins studies the rat that ere fed on diet of casein , starch ,sugar and inorganic
salt failed to grow and died .it was observed that rat could have survived with little of milk if
added to diet .and accessory food factor was found .
• 1913 – two group of workers isolated the factor from butter, egg yolk , cod liver oil and
reported that this factor was fat soluble.
• 1915 – Mccollum and Davis named it as fat soluble A
• 1920 – Rosenheim and Drummond indicated the relationship of vitamin A with carotene.
• 1957 –Moore proved that carotene was precursor of Vitamin A.
• Vitamin A is used for those retenoids that exhibit the biological activity of retinol.
• Retinol is used to describe related molecules like retinol ,retina l, retinoic acid , retinyl
etc.
• Vitamin A is collective name for a group of fat soluble vitamin .there are two compound
comprising of vitamin A activities : vitamin A1(retinol) and Vitamin A2 (3 dehydro retinol )
• RETINOL : It is the useable form of vitamin A and also called preformed Vitamin A
• STRUCTURE OF RETINOl
• it contains of hydrocarbon chain with β-ionone ring at one end and an alcohol group at
is pale yellow crystalline solid.

3. The hydroretinol or vitamin A2 that occurs in liver of some fish .it has only half the biological
activity of retinol. It is different from retinol by possessing an additional double bond between 3
and 4 carbon of B –Ionone ring .
RETINOL : it is found in animal source it is precursor of two form –retinal and retinoic acid.
The alcohol group –OH group oxidized in body to form aldehyde retinal or retinoic acid .retinal is
useful for vision and retinoic acid is helpful in transcription of number of genes.
the retinol stores in body as retinyl ester and the most common is retinyl palmitate.
Vitamin is doesn’t occur in pants but plants contain carotenoids like beta carotene that get
converted to vitamin A in intestine and other tissues. Beta carotenoids are the family of dark
pigments called provitamin A carotenoids .beta carotene splits in 2 in the body and form 2
molecules of retinol .both half are similar to the structure of retinol. Other carotenoids such as α
carotenoids and γ-carotenoids on cleavage yield one molecule of retinol
PHYSIOCHEMICAL PROPERTIES OF VITAMIN A
1. it is pale yellow almost courses liquid
2. It is soluble in fat and not in water
3. It can stand the 100 degress cooking temp in absence of oxygen
4. Fat containing retinol become rancid on oxidation and destroys the vitamin.
5. Retinol also get destroyed by sunlight
6. Oxidation can be prevented by adding vitamin E .

4. VITAMIN D :
Hughes Bennett recognized the nutritional value of cod liver oil.
1918 : it was used by trousseau in treatment of rickets
1918: Mellan by observed that rickets was responding to a fat soluble vitamin present in cod liver
liver oil
1931 : it was synthesized
Vitamin D has a group of sterols . Ergocalciferol (vitamin D2) and cholecalciferol or activated 7 –
dehydrocholesterol or vitamin D3.
Cholecalciferol is a type of steroid hormone made in the skin from the cholesterol when the skin is
in sunlight..
Process of creating vitamin D in sunlight :
Uv rays cleaves the B ring of both compounds ergosterol and dehydrocholesterol . and forms
ergocalciferol in plants and cholecalciferol in animal in the skin dehydrocholesterol converts into
cholecalciferol following uv rays .
The liver and other tissues metabolize these vitamin D to 25 dehydroxy vitamin and it further
metabolize into 1,25- dihydroxyvitamin D3 mainly in the kidney . 1,25 –dihydroxyvitamin D3 is
responsible for all biological actions .
Physio- chemical properties of vitamin D
1. Both Vitamin D2 and D3 are soluble in fats and fat solvents
2. They are not destroyed in presence of acid and alkali
3. Both compounds withstand cooking temp (of 100 degrees)
4. Vitamin D is more stable than vitamin A .

5. VITAMIN E (TOCOPHEROL)
1. Vitamin E is fat soluble vitamin and it function as lipid ,soluble antioxidant .
2. 1923 : evans and Bishop revealed its presence .
3. 1936 : Evans and coworkers isolated it from wheat germ oil and named as tocopherol .
4. 1938 : synthesis of the vitamin was accomplished by two groups .
5. Vitamin E is a group of compound known as tocopherols which is the derivative of TOCOL .
6. Four tocopherol like α ,β, γ , δ –tocopherol have been isolated .they differ from each other in
number and position of methyl group attached to aromatic nucleus.
7. Β and γ –tocopherol have two methyl groups attached to aromatic nucleus.
8. α and δ – tocopherol have three and one methyl group respectively.
9. α-tocopherol is commercially synthesized is potent .
STRUCTURE OF VITAMIN E
Tocopherol consist of ring portion called chromane head and ring and tail portion called a phytyl
group. A chromane head has two ring which are essentially naphthalene with one carbon atom
substituted with oxygen ,thus a cyclic ether and phytyl group consist of saturated 16 carbon
isoprenoid,
Isoprene is a branched chain unsaturated hydrocarbon of five carbon atoms.
Tocotrienol are essentially identical to tocopherol except that they have three double bond in the
tail at 3’,7’,11 .
PROPERTIES
1. They are yellow oiy liquid
2. They are soluble in fat solvents .

6. 3. They can withstand above 100 degrees .
4. Vitamin E is destroyed in presence of oxidizing agents .
5.In alkaline medium ,tocopherol are destroyed .They are stable to acidic medium
7 ultra violet light destroys vitamin .All these compound exhibit strong antioxidant properties
VITAMIN K
1. Vitamin K is important for blood clotting .
2. 1934 : it was observed by Dam and Schonheyder . that bleeding was unrelated to vitamin c
deficiency could be prevented by alfalfa or decayed fish meal .
3. 1935: extracted by Dam and named as vitamin k
4. 1939 : Dam ,Karrer isolated pure vitamin k1
5. 1939 :Doisy and coworker isolated K2.
6. Several compounds having vitamin k activity is known ,they are derivatives of naphthoquinone.
7. Eg,. vitamin k1 (phylloquinone) ,vitamin k2 (menoquinone); vitamin k 3 (menodione)
Vitamin k 1 occurs in plant food ,Vitamin k 2 is synthesized by bacteria .Vitamin k 3 is synthetic
compound . Out of all menadione is most potent of all .
Properties :
1.Vitamin k 1 is yellow oil ;vitamin k2 is yellow solid
2.They are soluble in fat .
3. They are sensitive to alkali , light and stable to heat .