Nicotinic acid and vitamin

Capillary zone electrophoresis is a powerful tool for the separation of water-soluble vitamins, such as nicotinic acid and vitamin C, with high-pH borate or phosphate buffers. Most simultaneous separations have been performed for fat-soluble vitamins, such as vitamins A and E, by MEKC. Here, organic... 

In a few cases vitamins in very high doses exert a pharmacological effect, e.g. vitamin A, nicotinic acid and vitamin D. 

In addition to thiamine, all mammalian species, so far as studied, require riboflavin, nicotinic acid, and vitamin A in their food. We conclude that the supply of food available to an earlier ancestor provided an adequate supply of these vitamins, enough to make it advantageous to discard the mechanism for synthesizing them. There is little doubt that this food was plant food, probably not greatly different from present day plant food. 

Nicotinic acid pyridine 3-carboxylic acid, 123.11, m.p. 234-237°C, first obtained in 1867 from the oxidation of nicotine. It is biologically important as a member of the vitamin Bj complex (see Vitamins). Isonicotinic hydrazide (INH), iff, 137.14, m.p. 163 °C, is an antitubeteulosis agent, which shows antivitamin properties against both nicotinic acid and vitamin B. ... 

Table 3. Nicotinic Acid and Nicotinamide (Vitamin B ) Content of Foodstuffs, mg/kg ...

Niacin was discovered as a nutrient during studies of pellagra. It is not strictly a vitamin since it can be synthesized in the body from the essential amino acid tryptophan. Two compounds, nicotinic acid and nicotinamide, have the biologic activity of niacin its metabolic function is as the nicotinamide ring of the coenzymes NAD and NADP in oxidation-reduction reactions (Figure 45-11). About 60 mg of tryptophan is equivalent to 1 mg of dietary niacin. The niacin content of foods is expressed as mg niacin equivalents = mg preformed niacin + 1/60 X mg tryptophan. Because most of the niacin in cereals is biologically unavailable, this is discounted. 

Chapter 10 is devoted to the preparation and purification of hydrophilic vitamins (C, Bj, Bj, Bg, B[2, nicotinic acid and nicotinamide, pantothenic acid, biotin, and folic acid) in pharmaceutical preparations, food products, and biological samples. 

A TLC method was developed for the estimation of nieotinie aeid and nicotinamide (Fignre 10.7) in phatmacentical preparations containing other vitamins, enzymes, herbs, and drugs, etc. [16]. The percentage recoveries for nicotinic acid and nicotinamide were 100.1 + 1.9 and 100.2 1.5, respectively, with this system. Each alcohol extract of samples or standard was pnt on sihca gel TLC plates, which were developed with distilled water. Each silica gel spot visualized under UV lamp was collected and extracted with 0.1 mol/1 HCl. The optical density of each clear extract was measured at 262 run. 

The vitamins niacin (nicotinic acid, and its amide niacin amide are... 

Vitamin Ba (pyridoxine, pyridoxal, pyridoxamine) like nicotinic acid is a pyridine derivative. Its phosphorylated form is the coenzyme in enzymes that decarboxylate amino acids, e.g., tyrosine, arginine, glycine, glutamic acid, and dihydroxyphenylalanine. Vitamin B participates as coenzyme in various transaminations. It also functions in the conversion of tryptophan to nicotinic acid and amide. It is generally concerned with protein metabolism, e.g., the vitamin B8 requirement is increased in rats during increased protein intake. Vitamin B6 is also involved in the formation of unsaturated fatty acids. 

We have developed a direct assay for vitamin Be in blood, serum, urine, cerebrospinal fluid, and tissue, based on the ciliate, Tetrahymena pyriformvs. The techniques are essentially those described for nicotinic acid (see Section 4.1), except that vitamin Be is omitted from the basal medium both nicotinic acid and its amide are added each at 0.1 mg/100 ml of basal medium. The method for blood, serum, urine, cerebrospinal fluid, and tissues is given below. 

The usable range for T. pyriformis is from 0.3-300 mug/ml. The organism utilizes pyridoxal, pyridoxamine pyridoxine, and pyridoxal-5-phosphate. Pyridoxamine + pyridoxal yielded the best growth approximately 120 times more pyridoxine is required to yield the same growth as pyridoxamine (Fig. 4). As with nicotinic acid and its amide, when these compounds are added together in the same concentration, the increment of growth is less than the sum of the individual increments. Upon an intramuscular load dose of 100 mg of pyridoxine, peak vitamin Bs levels are reached 2 hours after injection. The curves for 4 normal individuals are illustrated in Fig. 5. 

Group-transfer reactions often involve vitamins3, which humans need to have in then-diet, since we are incapable of realizing their synthesis. These include nicotinamide (derived from the vitamin nicotinic acid) and riboflavin (vitamin B2) derivatives, required for electron transfer reactions, biotin for the transfer of C02, pantothenate for acyl group transfer, thiamine (vitamin as thiamine pyrophosphate) for transfer of aldehyde groups and folic acid (as tetrahydrofolate) for exchange of one-carbon fragments. Lipoic acid (not a vitamin) is both an acyl and an electron carrier. In addition, vitamins such as pyridoxine (vitamin B6, as pyridoxal phosphate), vitamin B12 and vitamin C (ascorbic acid) participate as cofactors in an important number of metabolic reactions. 

Increased bilirubin levels are caused due to the intake of large doses of such drugs as chloroquine, vitamin K, sulpha-drugs, tetracyclines, paracetamol, nicotinic acid and monoamine oxidase inhibitors (e.g., iproniazid RP 1.0 nialamide RP 1.8 isocarboxazid RP 3.1 phenelzine RP 18 pheniprazine RP31 and tranylcypromine RP 45), where RP designates the Relative Potency based on the tiyptamine potentiation test. The elevated levels are due to hepatic injury, and... 

Pharmacology Niacin, vitamin B3, is the common name for nicotinic acid and niacinamide (nicotinamide). Nicotinic acid is present in the body as its active form, nicotinamide (niacinamide). 

Although nicotinic acid and nicotinamide function identically as vitamins, their pharmacologic effects differ. In large doses (up to 6 g/day), nicotinic acid is effective in reducing serum lipids (low-density lipoprotein [LDL], high-density lipoprotein [HDL], triglycerides, and lipoprotein A. Nicotinic acid produces vasodilation and increased blood flow due to histamine release. Nicotinamide does not affect blood lipid levels or the cardiovascular system. 

Niacin is also known as vitamin PP or vitamin Bj. The term niacin describes two related compounds, nicotinic acid and nicotinamide (Figure 19.18), both with biological activity. Niacin is formed from the metabolism of tryptophan, and therefore it is not strictly a vitamin. It is a precursor of two cofactors nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are essential for the functioning of a wide range of enzymes involved in redox reactions. 

The alkaloids are also relevant to drug design. Alkaloids are complex heterocyclic compounds that contain nitrogen and thus have base-like (hence the term alkaloid ) properties they are extremely structurally diverse. Nicotine is one of the simplest alkaloids. Oxidation of nicotine produces nicotinic acid, a vitamin that is incorporated into the important coenzyme nicotinamide adenine dinucleotide, commonly referred to as NAD" (oxidized form). The neurotransmitter serotonin is an alkaloid containing the aromatic indole ring system. 

Nicotine forms a number of metabolites in the body, mainly in the liver. Approximate 75% of nicotine is oxidized to cotinine, which is the primary nicotine metabolite. Cotinine can be measured in the blood, urine, and saliva and this is used as a measure of nicotine exposure in tobacco users and in those exposed to secondhand smoke. The oxidation of nicotine also produces nicotinic acid. Nicotinic acid is vitamin B3 and has the common name niacin. Niacin deficiency results in a disease called pellagra, which is found in certain malnourished populations. Pellagras symptoms include dermatitis, diarrhea, sensitivity to light, and dementia. 

Nicotinic acid and nicotinamide, members of the vitamin B group and used as additives for flour and bread enrichment, and as animal feed additive among other applications, are made to the extent of 24 million pounds (nearly 11 million kilograms) per year throughout the world. Nicotinic acid (pyridine-3-caiboxylic acid), also called niacin, has many uses. See also Niacin. Nicotinic acid is made by the oxidation of 3-picolme or 2-mcthyl-5-cthylpyridine (the isocinchomcnc acid produced is partially deearboxylated). Alternatively, quinoline (the intermediate quinolinic acid) is partially deearboxylated with sulfuric add in the presence of selenium dioxide at about 300° C or with nitric acid, or by electrochemical oxidation. Nicotinic acid also can be made from 3-picoline by catalytic ammoxidation to 3-cyanopyridine, followed by hydrolysis. 

VITAMIN B2 (Riboflavin). Some earlier designations for this substance included vitamin G, lactoflavin, hepatoflavin, ovoflavin, veidoflavin. The chemical name is 6,7-dimcthyl-9-d-l ribityl isolloxazine. Riboflavin is a complex pigment with a green fluorescence. Riboflavin deficiency frequently accompanies pellagra and the typical lesions of both nicotinic acid and riboflavin deficiency are found in that disease. See also Niacin. 

Niacin is one of the more stable water-soluble vitamins. Both nicotinic acid and nicotinamide are stable in air at ambient temperature (93,96). Aqueous solutions of nicotinic acid or nicotinamide can be autoclaved for short periods, e.g., 10 minutes at 120°C, without degradation. Nicotinic acid s stability in solution is independent of pH, but nicotinamide is stable only at neutral pH. Heating nicotinamide in 1 N acid or alkali at 100°C will induce its conversion to nicotinic acid. 

LV Hankes. Nicotinic acid and nicotinamide. In LJ Machlin, ed. Handbook of Vitamins. New York Marcel Dekker, 1984, pp 329-377. 

The term niacin is the generic descriptor for the two compounds that have the biological action of the vitamin nicotinic acid and nicotinamide (see... 

In order to more directly investigate the regulation of metabolism by the redox potential of the cell, we have recently labeled the intracellular pools of pyridine nucleotides in the liver, using the C-labeled vitamins, nicotinic acid and nicotinamide ... 

Tryptophan is probably the indole derivative most widely distributed in nature. It is converted into many other substances of important biological significance. The many materials biogenetically related to tryptophan include nicotinic acid (a vitamin), serotonin (a neurohormone), indoleacetic acid (a phytohormone), some pigments found in the eyes of insects, and a number of alkaloids. 

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