Every individual needs to know some important things, especially about nutrition to our health. Vitamin C is one of the important nutrient that helps in increasing immune response. It also helps in growth and development of the body by acting as Co- enzymes in various metabolisms. Even most of the cosmetic products containing Vitamin C.

1. BY
T.KEERTHIKA
M.Sc MEDICALBIOCHEMISTRY

3. CHEMISTRY
 Ascorbic acid is a hexose derivative and closely resembles
mono-saccharide in structure.
• It is water soluble and is easily destroyed by heat, alkali and
storage. In the process of cooking, 70% of vitamin C is lost.
• The strong reducing and acidic property of vitamin C depends
on the double-bonded (enediol) carbons.
• Only L-ascorbic acid and dehydroascorbic acid have
antiscorbutic activity. The D-ascorbic acid has no activity.
• L-Ascorbic acid undergoes oxidation to form dehydroascorbic
acid and this reaction is reversible. Ascorbic acid is active and
dehydroascorbic acid is inactive.

4. CHEMISTRY

5. Vitamin C - CHEMISTRY
Structural formula closely resembles that of carbohydrates

6. CHEMISTRY
Biosynthesis and metabolism
• Many animals can synthesize ascorbic acid from glucose
via uronic acid pathway.
• Humans cannot synthesize vitamin C due to deficiency of
L- gulonolactone oxidase.
• Vitamin C is rapidly absorbed from the intestine, it is not
stored in the body to a significant extent.
• Ascorbic acid is excreted in urine as such, or as in the
form of metabolites diketogulonic acid and oxalic acid.
• Oxidation of ascorbic acid is rapid in the presence of
copper, Hence vitamin C becomes inactive if the foods
are prepared in copper vessel.

7. L- ASCORBATE

8. Sources

10. Recommended dietary allowances
(RDA)
R
D
A
60mg for adults
70mg for pregnant women
95mg for lactating women
100mg for smokers
(Inhibits conversion of
irritants in tobacco smoke
into cancer-causing
substances)

11. Biochemical functions :
• Most of the functions of vitamin C are related to its property to undergo
reversible oxidation reduction i.e., Interconversion of ascorbic acid &
Dehydroascorbic acid.
1.Collagen formation
2. Bone formation
3. Iron and hemoglobin metabolism
4. Tryptophan metabolism
5.Tyrosine metabolism
6. Folic acid metabolism
7. Peptide hormone synthesis
8. Synthesis of corticosteroid hormones
9. Sparing action of other vitamins
10. Immunological function
11. Preventive action on cataract
12. Preventive action on chronic diseases

12. FUNCTIONS
As
antioxidant
Reduces risk
of cataract
Prevention of
atherosclerosis
– coronary HD
Prevention of
cancer

13. Post translational modification's of collagen
Proline → OH Proline
Lysine → OH Lysine
Tryptophan  OH Tryptophan
Enzyme: Hydroxylase, Coenzyme: Vit C
Protocollagen → Collagen
OH residues are required for cross linking of collagen
fibers.

14. Catecholamine
synthesis from
tyrosine

15. Catabolism of tyrosine
Parahydroxy phenylpyruvate
hydroxylase
Vitamin C

16. IRON
ABSORPTION
Vitamin C
enhances the
iron absorption
from intestine

17. Vitamin C
Vitamin C
Folate metabolism

18. Vitamin
C

19. Other protective functions
Promotes the healing of cuts, abrasions and wounds
Helps fight infections.
Inhibits conversion of irritants in tobacco smoke and
certain foods into cancer-causing substances.
Appears to dilate blood vessels and thereby lessen the
risk of developing high blood pressure and heart disease.
Helps regulate cholesterol levels.

20. DEFICIENCY MANIFESTATIONS
Haemorrhages in
various tissues
General weakness and
anaemia.
Swollen joints, swollen
gums and loose tooth.
Susceptible for
infections.
Delayed wound
healing.
Bone fragility and
osteoporosis.
SCURVY

21. Scurvy
Periodontal disease Bleeding gum Scurvy
Spongy and sore gums, loose teeth,
anaemia, swollen joints, fragile blood vessels,
decreased Immuno-competence delayed wound
healing, sluggish hormonal function of adrenal
cortex and gonads, haemorrhage osteoporosis.

22. THERAPEUTIC USES
Common
cold Cancer

23. THERAPEUTIC USES
• Beneficial effect of ascorbic acid is reported in the
treatment of tuberculosis,
– When plasma level is kept near to saturation point.
– Clinical dose is 500 mg per day.
• Because of its power to heal wounds, vitamin C has been
recommended for treatment of
– Ulcer
– Trauma &
– Burns.

24. Toxicity
 Diarrhea
 Nausea
 Skin irritation
 Burning upon urination
 Depletion of the mineral copper.
 Development of kidney stones due to oxalate
formation or hemochromatosis or other diseases
related to excessive iron accumulation.