ASCORBIC ACID

Brand Names : Vitamin C, Cevitamic acid; Cebid; Cebion; Cantaxin; Cevalin; Cevatine; Cevimin. Cevitex: Cewin Cioca; Cebicure; C-Vimin: Cevitamin: Testasco bie Altercorb: Cecon: Ce-Vi-Sol; Ascorin; Ascorteall; Cegionları Allerlex; Ascorevit, Ceyex; Lemascorb; Ciamin; Hybrin; Vitacee; Cantan; Catavin C; Celin; Cenetone; Cescorbat; Cereon; Cergona; Cetamican; Cetamid; Planavit C; Colascor; Concemin; DuOScorb; Scorbacid; Davitamon C; Proscorbin; Redoxon; Scrobu-C; Ribena; Vicelat; Vitacin; Vitacimin; Vitascorbol; Xiitix; Cevitan; Laroscorbine.

Ascorbic acid is widely distributed in the plants and animal kingdom. Good sources are citrus fruits, hipberries, acerola, freshtea leaves, peppers, paprikas, tomatoes, rose hips, blackberries, green English walnuts, West Indian (s cherries and other sources. It is formed rapidly in germinating seeds and apparently reaches a high concentration in rapidly growing stem or root tips, green leaves and seeds.

Although ascorbic acid occurs in relatively large quantities in some plants, fruits and other natural sources, its isolation is tedious, and difficult. Ascorbic acid is now manufactured from D-glucose via microbiological oxidation to a keto-acid, which is catalytically reduced to L-idonic acid. This is converted to 2oxo-L-gulonic acid in the presence of bacteria which is esterified with methanol. The ester is then isomerized and cyclized to Lascorbic acid.

The natural ascorbic acid is of L-series, though it is dextrorotatory. It undergoes reversible oxidation and reduction in the organism which owe its antiscorbutic activity. Its name ascorbic acid was given because it exhibited acid properties (sour taste) and would cure scurvy. The enolic group imparts acidity to the molecule and it can form salts. Vitamin C shows marked reducing properties but it does not produce colour with Schiffs base. It is quantitatively oxidized in aqueous solution by iodine or by 2,6-dichlorophenolindophenol and the oxidation process is reversible. Ascorbic acid is the least stable of all vitamins.

Ascorbic acid, m.p. 190-192°, occurs as odourless, colourless or slightly yellow crystals or crystalline powder with pleasant. sharp acidic taste. It is soluble in water and alcohol; practically insoluble in chloroform, benzene, oils, fats, ether and petrol. It is stable in air when dried. In impure preparations and in many natural products the vitamin oxidizes on exposure to air and light. It possesses relatively strong reducing power, and decolourizes many dyes. Aqueous solutions are rapidly oxidized by air and the reaction is accelerated by alkalies, iron and copper. It produces colour with ferric chloride and precipitated with basic lead acetate. It is kept in well-closed containers and protected from light.

Sodium Ascorbate (Brand Names : E 301; Monosodium Lascorbate; Vitamin C sodium; Ascorbin; Sodascorbate; Natrascorb; Cenolate; Ascorbicin; Cebitate), m.p. 218° (decomp), is prepared by treating aqueous ascorbic acid solution with an equivalent amount of sodium bicarbonate. After cessation of effervescence

Sodium ascorbate occurs as white or very faintly yellow, odourless crystals or crystalline powder. It gradually darkens on exposure to air. It is soluble in water; very slightly soluble in alcohol; insoluble in chloroform and ether. A 10% solution in water has a pH of 7 to 8. Aqueous solutions, are quickly oxidized by air at pH 6.0. It is stored in airtight containers and protected from light.

Uses: Ascorbic acid is essential for the synthesis of collagen and intercellular material. Its deficiency leads scurvy which is characterized by capillary fragility, bleeding, anaemias, cartilage and bone lesions and slow healing of wounds.

Ascorbic acid is used to treat scurvy and cold, to acidify urine, as antioxidants in pharmaceutical and food industries.

Side Effect

Large doses of Vitamin C causes diarrhoea and other gastro-intestinal disturbances.