Pharmacognosy- 413 Dr. Prawez Alam

Water soluble vitamins The vitamin B complex includes: Thiamine (Vitamin B1) Riboflavin (Vitamin B2) Niacin (Vitamin B3) Pantothenic Acid (Vitamin B5) Pyridoxine (Vitamin B6) Biotin (Vitamin B7)   Folic Acid (Vitamin B9)   Cyanocobalamin (Vitamin B12) Vitamin C Coenzymes: Catalysts in Biochemical Pathways

Coenzymes: Coenzyme, Any of a number of freely diffusing organic compounds that function as cofactors with enzymes in promoting a variety of metabolic reactions. Examples include nicotinamide adenine dinucleotide (NAD), which accepts hydrogen (and gives it up in another reaction), and ATP, which gives up phosphate groups while transferring chemical energy (and reacquires phosphate in another reaction). Most of the B vitamins (vitamin B complex) are coenzymes and are essential in facilitating the transfer of atoms or groups of atoms between molecules in the formation of carbohydrates, fats, and proteins.

1. Vitamin B1 Thiamine or vitamin B1 has substituted pyrimidine and thiazole rings linked by a methylene bridge.

Vitamin B1 The vitamin is stable in an acidic environment but decomposes readily above pH 5.0. It is estimated that about 50% of the vitamin in foods is destroyed during cooking.

Vitamin B1 Source: Plant: whole grains (unrefined cereal grain), yeast, beans, peas. Animal: liver, heart, kidney and milk.

Vitamin B1 FUNCTIONS: Acts primarily as a coenzyme in reactions that release energy from carbohydrate. Thiamin functions in the body as thiamin pyrophosphate (TPP). Thiamin TPP (Brain- Liver) Thiamine Diphosphotransferase

Deficiency: Beriberi: is a disease in which the body does not have enough thiamine (vitamin B1). Symptoms of dry beriberi include: Difficulty walking Loss of feeling (sensation) in hands and feet Loss of muscle function or paralysis of the lower legs Mental confusion/speech difficulties Symptoms of wet beriberi include: Increased heart rate Shortness of breath with activity Swelling of the lower legs

Dose: The US RDA of thiamine is 1.5 mg for adults and children over 4 years of age, 0.7 mg for children under 4 years of age, 0.5 mg for infants, and 1.7 mg for pregnant and lactating women. Thiamine is used to supplement an inadequate diet (rare) and to treat deficiency conditions resulting from intestinal mal-absorption of various etiologies, and from certain genetic errors.

2. Vitamin B2 Riboflavin or vitamin B2 is a yellow, heat-stable substance that is slightly soluble in water. It is sensitive to light and will change into lumichrome or lumiflavin, depending on whether the irradiated solution is acidic or alkaline; neither lumichrome nor lumiflavin possesses physiologic activity. Riboflavin can be synthesized chemically, but bacterial synthesis is more convenient and economical for commercial purposes.

Vitamin B2

Vitamin B2 Source: Yeast is the richest natural source of riboflavin. Dairy products, eggs, legumes, and meats are the main dietary sources of this vitamin. Small amounts are provided by cereal grains, fruits, and green vegetables. Riboflavin is stable during cooking in the absence of light.

Functions of Vitamin B2 Involved in energy metabolism; part of two co-enzymes, FMN (Flavin mononucleotide) and FAD (flavin adenine dinucleotide) FMN and FAD function as coenzymes in the transfer of electrons in a number of important biologic oxidation-reduction reactions. Participate in citric acid cycle and beta oxidation and electron transport Remove ammonia during deamination of some amino acids Associated with antioxidant glutathione peroxidase

Deficiency: Riboflavin deficiency is rarely encountered in healthy persons receiving a balanced diet, but symptoms of deficiency may occur in cases of inadequate nutrition, intestinal malabsorption. It should be noted that alcohol inhibits intestinal absorption of riboflavin. Riboflavinosis,The main symptoms are: Skin rash Dermatitis Cheilosis: fissures at the corner of the mouth Glossitis: tongue smooth and purplish

Dose: The US RDA of riboflavin is 1.7 mg for adults and children over 4 years of age, 0.8 mg for children under 4 years of age, 0.6 mg for infants, and 2.0 mg for pregnant and lactating women.

3. Vitamin B3 Niacin, nicotinic acid, or vitamin B3 is a simple, naturally occurring pyridine derivative that prevents pellagra. Niacinamide or nicotinamide also occurs naturally, has antipellagra activity, and is used for dietary and therapeutic purposes.

Sources of Vitamin B3 Lean meats, fish, and dairy products are good dietary sources of niacin; the vitamin is stable during cooking. Cereal grains and a number of other foods contain appreciable quantities of niacin The roasting of coffee beans results in the release of a significant quantity of niacin as well as in the development of a characteristic flavor. Tryptophan is also converted to niacin in the body. It is estimated that 60 mg of tryptophan is approximately equivalent to 1 mg of niacin.

Functions of Vitamin B3 Niacin is metabolized to niacinamide which is a component of nicotinamide adenine dinucleotide (NAD), or coenzyme I, and nicotinamide adenine dinucleotide phosphate (NADP), or coenzyme II. These coenzymes are involved in electron transport in a large number of essential enzyme systems associated with glycogenolysis, lipid metabolism, and tissue respiration.

Deficiency: Pellagra is classically described by "the four D's": • Diarrhea: • Dermatitis: Dermatitis is a blanket term meaning any "inflammation of the skin" (e.g. rashes, etc.) • Dementia: • Death:

Dose: The US RDA of niacin is 20 mg for adults and children over 4 years of age, 9 mg for children under 4 years of age, and 8 mg for infants.

4. Vitamin B5       Pantothenic acid or vitamin B5 is a component of the vitamin B complex that is sometimes known as the "chick antidermatitis factor“.

Vitamin B5 Source: Animal organs (heart, kidney, and liver) and cereal grains are rich dietary sources of pantothenic acid.

Vitamin B5 FUNCTIONS: It acts as a carrier in many enzymatic reaction involved in: 1. Fatty acid oxidation and synthesis. 2. Oxidative decarboxylation of -keto acids. 3. Formation of citric acid in citric acid cycle. Acetyl CoA + Oxaloacetate Citrate, 4. Cholesterol synthesis

Deficiency: The most distinctive of the deficiency symptoms are paresthesias of the extremities or "burning foot" syndrome.

Dose: The US RDA for pantothenic acid is 10 mg for adults and children over 4 years of age, 5 mg for children under 4 years of age, and 3 mg for infants.

5. Vitamin B6 Vitamin B₆ consists of 3 closely related pyridine derivatives: pyridoxine, pyridoxal pyridoxamine All three compounds are efficiently converted to the biologically active form of vitamin B₆ pyridoxal phosphate Pyridoxal Pyridoxal Phosphate PLP Pyridoxal Kinase

Sources of Vitamin B6 Meats, bananas, whole cereal grains, nuts, and potatoes are good dietary sources of vitamin B6. Up to 40% of its activity may be lost during cooking.

Functions of Vitamin B6 Pyridoxal phosphate (PLP) is the active form and is a cofactor in many reactions of amino acid metabolism, including: Transamination, Deamination, Decarboxylation. PLP also is necessary for the enzymatic reaction governing the release of glucose from glycogen. PLP Converts tryptophan into niacin.

Deficiency: Symptoms of vitamin B6 deficiency somewhat resemble those of niacin and riboflavin deficiencies. They include neurologic abnormalities (confusion, irritability, and convulsive seizures), and skin lesions (glossitis, seborrheic dermatitis, and stomatitis).

Dose: The US RDA for pyridoxine is 2 mg for adults and children over 4 years of age, 0.7 mg for children under 4 years of age, 0.4 mg for infants, and 2.5 mg for pregnant and lactating women.

6. Vitamin B7 Biotin, D-biotin, or vitamin H is a physiologically active substance that consists of fused imidazolidone and tetrahydrothiophene rings and a valeric acid side chain.

Sources of Vitamin B7 Egg yolk, liver, cereal grains, and milk are good dietary sources of biotin, but commercial supplies are prepared by chemical synthesis.

Functions of Vitamin B7 It is also important in energy metabolism This vitamin functions as a carboxyl-carrying cofactor in several carboxylase and decarboxylase enzyme systems. Biotin plays an important role in fat, amino acid and carbohydrate metabolism

Deficiency: Deficiency: is rare because it is found in numerous foods and is synthesized by intestinal bacteria.

Dose: The US RDA for biotin is 300 g for adults and children over 4 years of age, 150 g for children under 4 years of age, and 50 g for infants.

7. Vitamin B9 Folic acid, folacin, pteroylglutamic acid, and occasionally vitamin B9 are terms that refer to a material with antianemia properties. It is a conjugate of a pteridine derivative, p-aminobenzoic acid, and glutamic acid

Sources of Vitamin B9 Leafy vegetables (origin of the term "folic") and liver are good dietary sources of pteroylpolyglutamates (folates), the primary dietary forms of this vitamin.

Functions of Vitamin B9 Vitamin B9 (Folic acid and Folate inclusive) is essential to numerous bodily functions ranging from nucleotide synthesis to the remethylation of homocysteine. It is especially important during periods of rapid cell division and growth. Both children and adults require folic acid to produce healthy red blood cells and prevent anemia.

Dose: The US RDA of folic acid is 0.4 mg for adults and children over 4 years of age, 0.2 mg for children under 4 years of age, 0.1 mg for infants, and 0.8 mg for pregnant and lactating women.

8. Vitamin B12 Vitamin B12 and cobalamins are terms that refer to a series of porphyrin-related corrinoid derivatives that function as extrinsic factors to prevent pernicious anemia. Cyanocobalamin, a red crystalline material, is the most stable of the cobalamins; consequently, it is the form of vitamin B12 most frequently utilized in therapy.

Vitamin B12

Sources of Vitamin B12 Meat, seafood, eggs, dairy products, and fermented foods, such as soy sauce, are good dietary sources of the vitamin.

Functions of Vitamin B12 The cobalamins are essential to cell reproduction, growth, hematopoiesis, and synthesis of myelin and nucleoprotein.

Deficiency: Pernicious anemia (is a condition in which the body can not make enough healthy RBC because it does not enough vitamin B12) Symptoms of vitamin B12 deficiency usually involve rapidly dividing cells of the hematopoietic system (e.g., megaloblastic anemia) and irreversible neurologic damage (e.g., defective myelin nerve sheaths); they include irritability, weakness, memory loss, mood swings, and a sensation of tingling or numbness of the arms and legs.

Dose: The US RDA of vitamin B12 is 6 g for adults and children over 4 years of age, 3 g for children under 4 years of age, 2 g for infants, and 8 g for pregnant and lactating women.

9. Vitamin C Vitamin C or L-ascorbic acid is a naturally occurring vitamin substance that prevents scurvy and has useful antioxidant properties. It occurs in equilibrium with dehydro-L-ascorbic acid, an oxidized form, which also has antiscorbutic properties.

Vitamin C: L-Ascorbic acid is derived biosynthetically from D-glucose, D-galactose, or other sugars Most commercial supplies of this vitamin are obtained by chemical synthesis starting with D-glucose.

Sources of Vitamin C Good dietary sources of ascorbic acid include citrus fruits, tomatoes, strawberries, and other fresh fruits and vegetables. Although the vitamin content is preserved on freezing, up to 50% of the vitamin C content is lost upon cooking. The maximum intestinal absorption capacity is about 1200 mg per 24 hours.

Functions of Vitamin C This vitamin is essential for proper formation of collagen and other intercellular materials in tissues, especially in bones, skin, and teeth. It also appears to be associated with hydroxylases that act on cholesterol and tyrosine to produce corticosteroids and catecholamines, respectively. Vitamin C likewise is involved in biologic oxidation-reduction reactions (hydrogen and electron transport).

Deficiency: Scurvy: (collagen degeneration) Other symptoms include fatigue, muscular pain, increased susceptibility to infection and stress, skin lesions, bleeding gums.

Dose: The US RDA for ascorbic acid is 60 mg for adults and children over 4 years of age, 40 mg for children under 4 years of age, and 35 mg for infants. It is estimated that pregnant and lactating women may require 100 mg per day. Patients who smoke or who have gastrointestinal disease, cancer, peptic ulcer, hyperthyroidism, stress, or severe burns also may require increased vitamin C supplementation.

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