Vitamin B2

1. RIBOFLAVIN(VITAMIN B2)

2. INTRODUCTION
 Riboflavin(vitamin B2) is part of the vitamin B group.
 Riboflavin is a water soluble vitamin.
 The name riboflavin comes from ribose and flavin, the ring
moiety which imparts from the yellow colored to the oxidized
molecule.
 Riboflavin is absorbed from the small intestines through the
portal vein and is passed on to all tissues by the general
circulation.
 Excess riboflavin ingested is not stored in the tissues.
 A major part is excreted in urine and a small part is broken
down in the tissues.
 It is the central component of the cofactors FAD and FMN and
as such required for a variety of flavoprotein enzyme reactions
including activation of other vitamins.

3. Structure
Riboflavin (Vitamin B2 )
Molecular formula C17H20N4O6

4. Dietary sources
Liver, dried yeast, egg powder, whole and skim milk
powder are the richest natural sources of
riboflavin.
Fresh milk, eggs, meat and fish, whole cereals and
legumes and green leafy vegetables are good
sources.
Cereal products, roots and tubers other vegetables
are fair sources.

5. Physiological and biochemical function
Riboflavin deficiency affects primarily the octodermal
tissues producing lesions of the skin, eye and nervous
system.
Riboflavin is concerned in the regulatory functions of
some hormones involved in carbohydrate metabolism.
The retina contains free riboflavin which is converted
by light to a compound involved in stimulation of the
optic nerve.
Riboflavin play an important role in many enzyme
systems involved in the metabolism of carbohydrates,
fats and proteins.
Riboflavin mononucleotide(FMN) and riboflavin
adenine dinucleotide(FAD) are part of the enzymes or
acts as coenzymes.

6. Effects of deficiency
 The effects of riboflavin deficiency in human beings may be
grouped under the following heads
– Oral and facial lesions
Development of angular stomatitis, Glossitis, cheilosis
Angular stomatitis Glossitis Cheilosis

7. Ocular lesions:
The eyes can become itchy, watery, bloodshot and
sensitive to light.

8. Daily requirements:
Men -- 1.3 to 2.2mg/day
Women -- 1.0 to 1.7mg/day
Pregnancy -- 0.2mg/day
Lactation -- 0.4mg/day
Infants -- 0.4 to 0.5mg/day
Children -- 0.5 to 1.2mg/day
Adults -- 1.2 to 1.7mg/day