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Vitamins
Vitamin B complex
Definition:
“Vitamin B complexes are a class of water-soluble vitamins that play important role in cell metabolism.”
Members of Vitamin B complex
The members of Vitamin B complex group consist of
1) Vitamin B1 (Thiamine)
2) Vitamin B2 (Riboflavin)
3) Vitamin B3 (Pantothenic acid)
4) Vitamin B5 (Niacin)
5) Vitamin B6 (Pyridoxine)
6) Vitamin B7 (Biotin)
7) Vitamin B9 (Folic acid)
8) Vitamin B12 (Cyano cobalamin)
Vitamin B1 (Thiamine)
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First member of Vitamin B group
First isolated by Jansen and Adolf Windaus
Occurrence:
They are found in variety of substances such as:
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Thiamine is found practically in all plants and animal foods.
Cereals, heart, liver and kidney are excellent source of it.
In cereals the outer layer of seeds are typically rich in thiamine.
In yeast and animal tissues.
Milk also contains thiamine in low amount.
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Structure
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The chemical structure of thiamine was determined in 1935 by Robert R.Williams and his
associates in the united states.
Thiamine molecular formula (C12H17N4O8)
Thiamine is 2,5-dimethyl-6-aminopyrimidine bonded through a methylene linkage to 4-methyl-5
hydroxyethyl-thiazole .
Thus pyrimidine and thiazole are the two moieties present in molecules.
Pyrimidine moiety
Thiazole moiety
Biochemical function
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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.
It helps prevent diseases such as beriberi.
It helps prevent complications in the nerve system, brain, muscle, heart, stomach, and
intestines.
It is also involved in the flow of electrolytes into and out of muscle and nerve cells.
Anti-stress vitamins because they boost the body’s immune system in time of stress.
Vitamin B2 (Riboflavin)
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Riboflavin or vitamin B1 was isolated in 1879 from milk.
Also known as lactoflavin.
Occurrence:
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In nature it occurs as constituent of one of the two flavin coenzyme namely, FMN and FAD.
It is present in milk, cheese, eggs, liver, kidney, heart and brewer’s yeast.
Fruits and root vegetables contain moderate quantities.
Structure:
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C17H2ON4O6 belong to class of water-soluble pigments called lyochromes. A molecule of thiamine
consists of sugar.
Alcohol, D-ribitol, attached to a chromogenic methyl isoalloxazine ring at position no. 9
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Biochemical function:
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Riboflavin is concerned in the regulatory functions of some hormone involved in carbohydrate
metabolism.
Riboflavin mononucleotide FMN riboflavin adenine dinucleotide FAD are part of the enzymes or
acts as coenzyme.
Play an important role in many enzyme growth, repair, development of body tissues.
Vitamin B3 (Pantothenic acid)
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Isolated by Roger J.Williams in 1938 from yeast and liver. This vitamin is sometimes called as
…......factor or the yeast factor.
Occurrence:
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Yeast, liver and eggs are the richest source of it.
The vegetables(potatoes,sweet,cabbage,cauliflower,broccoli) and fruits
(tomatoes,peanuts), skimmed milk, wheat, bran, whole milk and canned salmon.
Structure:
Pantothenic acid is an amide of pantoic acid and B-alanine.
Pantoic acid moiety
Alanine moiety
Biochemical function:
Pantothenic acid is used in the synthesis of coenzyme A. Coenzyme A may acts as an acyl group
carrier to form acetyl-COA and other related compounds, this is a way to transport carbons
atoms within the cell.
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Vitamin B5 (Niacin)
It is also called nictonic acid.
Occurrence:
Widely distributed in nature in plant and ………..tissues mainly as its amide called nictionamide,
liver , lean, pork, salmon, poultry, and red meat are also good source and small amount is
present in cereals.
Structure:
Niacin(C6H5O2N) is simplest of all the known vitamins. It is a pyridine derivative.
Nicotionic acid or Niacin
Nicotinamide or Niancinamide
Biochemical Function:
It is used in the synthesis of Coenzyme A which is important in biosynthesis of compound such as
fatty acids, cholesterol, and acetyl……..
Vitamin B6 (Pyridine)
Occurrence:
Widely distributed in nature in plant and animal tissues
Rich in cereals (wheat,rice), peas, turnip greens