Vitamin B2, also known as riboflavin, is a water-soluble vitamin that plays an important role in metabolism. It exists in tissues tightly bound to enzymes called flavoproteins and its active forms are FMN and FAD, which are involved in oxidation-reduction reactions. Good dietary sources include liver, eggs, dairy products, fish, and green leafy vegetables. A riboflavin deficiency can cause symptoms affecting the skin and mucous membranes like angular stomatitis or a magenta colored tongue.

1. VITAMIN B2
RIBOFLAVIN
Name : SAKSHI
Roll no. : 90

2. • Introduction
• Appearance
• Structure
• Coenzyme activity
• Deficiency
• Dietary sources
• Daily requirement
• Functions
• Benefits

3. INTRODUCTION
• Riboflavin was first isolated by Blyth in 1879 from cow-milk whey, that glowed
yellowy-green when exposed to light.
• Riboflavin is an organic compound found in many plants and animal products.
• Vitamin B2 is a water soluble vitamin.
• It is sensitive to light. Cooking in open container and in excess water is
harmful.(kept in dark and opaque container)
• Play a active role in breakdown of carbohydrate, protein, ketone bodies and fat.
• Molecular formula C17H20O6N4

4. • Vitamin B2 is closely related to yellow water soluble
pigment known as flavines(isoalloxazines), and since it was
first isolated from milk, vitamin B2 is also known as
lactoflavin.
• Riboflavin is poorly soluble in water as compared to other
vitamins of B complex group.
• It is yellow, fluorescent material so is also named
lactochrome.

5. Riboflavin has a dimethyl isoalloxazine ring to
which a ribitol is attached.
Ribitol is the alcohol of ribose sugar.
 Riboflavin is converted to its active co-enzyme
forms (FMN and FAD) with the help of ATP.
Stable to heat, oxidation, and acid.
Light and alkali destroys it.

6. CO-ENZYME ACTIVITY OF
RIBOFLAVIN
 Riboflavin exists in tissues tightly bound
with enzymes. Enzymes containing riboflavin are
called flavoproteins.
 Riboflavin is the component of two flavin
enzymes
The two co-enzymes are FMN (flavin mono
nucleotide) and FAD (flavin adenine dinucleotide)
 Both these flavin enzymes take part in various
oxidation-reduction reaction
The oxidized flavins are yellow in colour, while on
reduction they become colourless.

7. Riboflavin and its coenzymes are involved in:
1.Growth and tissue respiration
2.Light adaptation
3.Cellular metabolism
4.Enzymatic oxidation of glucose, amino acid, fatty acids,
purines etc.

9. • Causes : Natural deficiency of riboflavin in man is
uncommon, because riboflavin is synthesized by the intestinal
flora. Riboflavin deficiency usually accompanies other
deficiency diseases such as beriberi, pellagra and
Kwashiorkor.
• Manifestations: Symptoms are confined to skin
and mucous membranes.
i. Glossitis (Gk, glossa = tongue)
ii. Magenta coloured tongue

10. iii. Cheilosis (Gk, cheilos = lip)
iv. Angular stomatitis
v. Circumcorneal vascularization
vi. Proliferation of the bulbar conjunctival
capillaries is the earliest sign of riboflavin
deficiency.
These symptoms leads to ARIBOFLAVINOSIS

11. DIETARY SOURCES OF RIBOFLAVIN
 Rich sources are liver, dried
yeast, egg and whole milk.
 Good sources are fish, whole
cereals, legumes and green
leafy vegetables.

12. Daily Requirement
Riboflavin is concerned mainly with the metabolism of
carbohydrates and requirement is related to calorie intake.
• Infants = 0.3 – 0.4 mg/day
• Children = 0.5 – 0.9 mg/day
• Adults = 1.5 mg/day
• During pregnancy, lactation and old age = 1.4 - 1.6 mg/day

13. Riboflavin is involved with –
• production of FMN & FAD
• Activation of vitamin B6
• Conversation of tryptophan it niacin
• Conversion of folate to its coenzyme
• Aids in beta oxidation in fat metabolism, proteins and carbohydrates.
• Helps repair damaged tissues and wounds
• Active in formation of RBC
Riboflavin is needed for the production of corticosteroids; erythropoiesis;
gluconeogenesis; and thyroid enzyme regulation.

14. • It actually neutralizes the free radicals in our body and can help in
prevention of cancer and heart diseases.
• Helps in keep mucous membrane in our body healthy including those
in our mouth.
• Aids in prevention of headache, vision problems and even cataracts.

15. THANK YOU
Resources
 Harpers biochemistry
 Satyanarayana
 Vasudevan