Acids niacin

Nicotinic acid (niacin, 2-yridine-3-carboxylic acid) [59-67-6] M 123.1, m 232-234 , pKj 2.00, pK2 4.82. Crystd from benzene. 

Folic Acid Niacin Biotin Vitamin B1 Vitamin B2 Vitamin B6 Vitamin B12 Vitamin C... 

Nicotinic acid (niacin) Liver, lean meats, cereals, legumes Energy metabolism... 

Adsorbate Molecular Orientation at Electrode Surface. Adsorption of some molecules from solution produces an oriented adsorbed layer. For example, nicotinic acid (NA, or 3-pyridinecarboxylic acid, niacin, or vitamin B3) is attached to a Pt(lll) surface primarily or even exclusively through the N atom with the ring in a (nearly) vertical orientation (12) (Fig. 10.5a). 

Oxidation of nicotine with chromic acid led to the isolation of pyridine-3-carboxylic acid, which was given the trivial name nicotinic acid. We now find that nicotinic acid derivatives, especially nicotinamide, are biochemically important. Nicotinic acid (niacin) is termed vitamin B3, though nicotinamide is also included under the umbrella term vitamin B3 and is the preferred material for dietary supplements. It is common practice to enrich many foodstuffs, including bread, flour, corn, and rice products. Deficiency in nicotinamide leads to pellagra, which manifests itself in diarrhoea, dermatitis, and dementia. 

Pharmacology Niacinamide is synonymous with nicotinamide, 3-pyridine carboxamide, and nicotinic acid amide. Niacinamide is the amide of nicotinic acid (niacin, vitamin B3). Although nicotinic acid and nicotinamide function identically as vitamins, their pharmacologic effects differ. Nicotinamide does not have the hypolipidemic or vasodilating effects characteristic of niacin (nicotinic acid). 

Nicotinic acid (niacin) Yes Reduces LDL Reduces VLDL Raises HDL IV Ik with fibrates severe IV with fibrates Cutaneous flush, GI distress, liver dysfunction, hyperglycemia, hyperuricemia... 

Nicotinic acid (niacin) Nicotinamide adenine dinucleotide Dehydrogenation of proteins in cellular respiration... 

N. americanus—Necator americanus N. gonorrhoeae—Neisseria gonorrhoeae NA—nicotinic acid (niacin)... 

As aromatic compounds have been exhausted as building blocks for life science products, A-heterocyclic structures prevail nowadays. They are found in many natural products, such as chlorophyll hemoglobin and the vitamins biotin (H), folic acid, niacin (PP), pyridoxine HCl (Be), riboflavine (B2), and thiamine (Bi). In life sciences 9 of the top 10 proprietary drugs and 5 of the top 10 agrochemicals contain A-heterocycIic moieties (see Tables 11.4 and 11.7). Even modern pigments, such as diphenylpyrazolopyrazoles, quinacri-dones, and engineering plastics, such as polybenzimidazoles, polyimides, and triazine resins, exhibit an A-heterocydic structure. 

Castanea crenuta Sieb. et Zucc. C. mollissima Blume Japan Su (Chestnut) (flower, stem bark) Quercetin, urea, protein, beta-carotene, riboflavin, thiamine, ascorbic acid, niacin.48-50 Treat diarrhea, poisoned wounds, lacquer poisoning, astringent. 

Two vitamins, nicotinamide and pyridoxine (vitamin B6), are pyridine derivatives. Nicotinamide participates in two coenzymes, coenzyme I (65 R = H) which is known variously as nicotinamide adenine dinucleotide (NAD) or diphosphopyridine nucleotide (DPN), and coenzyme II (65 R = P03H2) also called triphosphopyridine nucleotide (TPN) or nicotinamide adenine dinucleotide phosphate (NADP). These are involved in many oxidation-reduction processes, the quaternized pyridine system acting as a hydrogen acceptor and hydrogen donor. Deficiency of nicotinamide causes pellagra, a disease associated with an inadequately supplemented maize diet. Nicotinic acid (niacin) and its amide are... 

Antagonists of folic acid include aminoplerin (4-aniino-ptcroylglulamic acidj. methotrexate tamethopterin), pyrimethamine, and 4-ammo-picroylas-partic acid. Synergists include biotin, pantothenic acid, niacin, vitamins B. Bo Bf, B 2. C, and E. somatotrophin (growth hormone), and testosterone. 

The beneficial and adverse effects of nicotinic acid (niacin) have been reviewed (12). Standard nicotinic acid from an immediate-release formulation is metabolized primarily by conjugation, which results in a high frequency of flushing. Long-acting nicotinic acid is metabolized through the nicotinamide pathway, which results in less flushing but increases the risk of hepatotoxicity. Modified-release nicotinic acid, on the other hand, has a more balanced metabolism and causes fewer of both types of adverse effects. 

Callanan D, Blodi BA, Martin DF. J Macular edema with nicotinic acid (niacin). J Am Med Assoc 1998 279 1702. 

Carlson LA. Niaspan, the prolonged release preparation of nicotinic acid (niacin), the broad-spectrum lipid drug. IntJ Clin Pract. 2004 58 706-713. 

The fat-soluble vitamins are A, D, E, and K. The water-soluble vitamins are thiamine (vitamin Bj), riboflavin, nicotinic acid (niacin) and nicotinamide, pyridoxine (vitamin B6), pantothenic acid, biotin, para-aminobenzoic acid, choline, inositol, and other lipotropic agents, ascorbic acid (vitamin C), the riboflavonoids, folate, and vitamin B12 (see Figure 66.1 and Figure 66.2, and Table 66.1). 

There are exceptions to the above. Most or all vitamins can be synthesized chemically. Vitamin D can be synthesized in the skin of animals by exposure to ultraviolet irradiation, and nicotinic acid (niacin) can be synthesized in the body from the AA tryptophan. 

Prior to 1987, the lipid-lowering armamentarium was limited essentially to dietary changes (reductions in saturated fats and cholesterol), the bile acid sequestrants (cholestyramine and colestipol), nicotinic acid (niacin), the fibrates, and probucol. Unfortunately, all of these treatments have limited efficacy or tolerability or both. Substantial reductions in LDL cholesterol (up to 47%) accompanied by increases in HDL cholesterol of up to 32% could be achieved by the combination of a lipid-lowering diet, a bile acid sequestrant, and the subsequent addition of nicotinic acid (Illingworth et al., 1981). However, this therapy is not easy to administer or tolerate and was therefore often unsuc-... 

Many cells require media supplemented with complex B vitamins, while other vitamins are presumably supplied by the addition of serum to culture media. Nevertheless, when serum-free media are employed, not only the water-soluble vitamins should be provided, but also the lipid-soluble ones, such as biotin, folic acid, niacin, panthotenic acid, thiamine, and ascorbic acid, as well as the vitamins B12, A, D, E, and K. 

---