The folic acid and Vitamin C the other two important water soluble vitamins.
From the Latin word 'folium' the name folic acid was derived, which means leaf because it was first obtained from spinach leaf and it was found to be widely distributed in green leaves. Chemically, it is pteroyl glutamic acid. The names folinic acid and folacin are now used as synonyms of folic acid.
As folic acid is widely distributed in green leafy vegetables e.g., spinach, curry leaves, mint, cabbage etc., It is also abundantly found in yeast, liver, kidney etc., and is synthesized by intestinal flora.
Folic acid acts as a coenzyme in its reduced form tetrahydrofolic acid which is involved in reactions concerning transfer of one carbon groups or metabolism of one carbon compounds. Such reactions are important in metabolism of amino acids and nucleic acids, particularly synthesis of DNA and thereby cell division. Thus, folic acid promotes formation of red and white blood cells.
Folic acid deficiency is produced by drugs killing theintestinal microflora or folic acid antagonists (e.g., aminopterin). The main symptoms of folic acid deficiency are megaloblastic or macrocytic or pernicious anemia and leucopenia. In some cases, diarrhea and gastrointestinal lesions may also be associated with the above mentioned symptoms.
Vitamin C is clinically called antiscorbutic vitamin since it prevents the disease called scurvy. Chemically, it is an acid called ascorbic acid. Its oxidized form dehydroascorbic acid is also biologically active as vitamin C.
Vitamin C is present in more or less all fruits and vegetables. Citrus fruits e.g., lemon, orange, amlaki, pineapple, mango etc., are outstanding sources. Fruits and vegetables contain an enzyme called ascorbic acid oxidaze which inactivates ascorbic acid by oxidizing it when exposed to oxygen. Dry legumes and pulses, yeast, maize, wheat and animal products like fish, meat, milk etc., contain negligible amount of this vitamin.
The primary function of ascorbic acid in the body is to act as coenzyme for oxidation-reduction and hydroxylation reactions, and thereby it takes part in-
i) Metabolism of amino acid
ii) Synthesis of collagen and other intercellular cementing materials
iii) Iron absorption
iv) Formation of adrenocortical hormones.
Ascorbic acid also exerts the following functions that are secondary to its above mentioned actions-
i) Formation of connective tissues, maintenance of the integrity of tissues like bones, teeth and capillaries, and wound healing
ii) Erythropoiesis by promoting absorption of iron for hemoglobin synthesis
iii) Anti-stress action through synthesis of adrenal corticoids.
Deficiency of vitamin C produces a disease called scurvy which is chracterised by defect in formation
and maintenance of intercellular cementing material and connective tissue. The chief symptoms are as follows :
i) Failure of wound healing.
ii) Fragility of capillaries and tendency of hemorrhage.
iii) Defective formation and loosening of teeth associated with spongy and bleeding gums.
iv) Skeletal weakness and fragility of bones.
v) Anaemia due to hemorrhage and impaired absorption of iron.
vi) Skin rash.