Two isomers L-ascorbic acid-. Active form. Configuration similar to L-glucose. L-Dehydroascorbic acid is the oxidized form L-ascorbic acid is the reduced form D-Ascorbic acid- Inactive in humans METABOLITIES Chief end products are: Oxalic acid Diketogulonic acid ABSORPTION From small intestine Normal level: 0.6 – 1.0 mg /100ml Exists in body largely in the reduced form

1. Anti-Scorbutic Vitamin
VITAMIN C
Maryam Fida (o-1827)
Source: Biochemistry – Lippincott’s Illustrated Reviews
World Wide Web

2. Vitamin C
Two isomers
■ L-ascorbic acid-. Active form. Configuration
similar to L-glucose.
– L-Dehydroascorbic acid is the oxidized form
– L-ascorbic acid is the reduced form
■ D-Ascorbic acid- Inactive in humans

4. Metabolites
Chief end products are:
■ Oxalic acid
■ Diketogulonic acid

5. Absorption
■ From small intestine
■ Normal level: 0.6 – 1.0 mg /100ml
■ Exists in body largely in the reduced form

8. Food Sources
■ In Plant and animal tissue
■ No storage in animal tissue
■ Highest concentration in highly active organs: adrenal cortex,
corpus luteum, liver etc.
Dietary sources
■ Citrus fruits
■ Leafy vegetables

12. Metabolic role
Cellular oxidation reduction:
■ Vit.C is very sensitive to reversible oxidation
■ Ascorbic Acid Dehydroascorbic Acid
■ Involved in cellular oxidation-reduction reactions

13. ■ Role in Collagen Synthesis:

14. ■ Proline Hydroxyproline
■ Lysine Hydroxylysine
■ Without hydroxylation, collagen cannot form triple helix
Proline Hydroxylase
Vit. C, Fe++, Mol. O2
Lysine Hydroxylase
Vit. C, Fe++, Mol. O2

15. Formation of tetrahydrofolate (FH4)
■ The reaction Folic Acid FH4 requires ascorbic acid
■ Necessary for utilization of Folic acid
■ Also keeps FH4 in reduced form

17. Role in iron absorption
■ Helps in reducing Fe+++ to Fe++
■ Helps in absorption of iron from intestine (iron absorbed in Fe++ form)

19. Deficiency (Scurvy)
■ May occur in artificially fed infants
■ Elderly people living alone
■ Alcoholics, drug addicts

20. Clinical picture
■ Increase capillary fragility
■ Bleeding from nose, mouth GIT, urinary
tract etc
■ Most frequent site is gums- swollen and
spongy. Show redness, swelling, ulceration

21. Cause of Scurvy
■ Hydroxylation of Proline and Lysine in Collagen
Synthesis does not take place
■ Without hydroxylation, collagen cannot form triple
helix

22. ■ Anemia , weakness, emaciation
■ Bleeding into joints (atraumatic
hemathrosis)
■ Delayed wound healing