Nicotinamide/nicotinate

C iH5N02 59-67-6) see Aluminum nicotinate Inositol nicotinate Micinicate Nicorandil Nicotinamide Nicotinic acid benzyl ester Nikethamide Xantinol nicotinate nicotinonitrile... 

Hydrolysis azathioprine benorylate diazepam diphenhydramine frusemide furazolidone nitrofurantoin menaquinone-4 mercaptopurine methotrexate nalidixic acid nicotinamide nicotine nicotinic acid nifedipine... 

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). 

Noncarcinogens acrolein, biphenyl, choline, eugenol, nicotinamide, nicotinic acid, N=8 phenol, piperidine... 

Figure 8.2. Synthesis of NAD from nicotinamide, nicotinic acid, and qninolinic acid. Quinolinate phosphoribosyltransferase, EC 2.4.2.19 nicotinic acid phosphoribosyl-transferase, EC 2.4.2.11 nicotinamide phosphoribosyltransferase, EC 2.4.2.12 nicotinamide deamidase, EC 3.5.1.19 NAD glycohydrolase, EC 3.2.2.S NAD pyrophosphatase, EC 3.6.1.22 ADP-ribosyltransferases, EC 2.4.2.31 and EC 2.4.2.36 and poly(ADP-ribose) polymerase, EC 2.4.2.30. PRPP, phosphoribosyl pyrophosphate.

The intracellular NAD glycohydrolase is now known as ADP-ribose cyclase there is also a cell surface ectozyme, identical with the lymphocyte CD38 antigen. CD38 also occurs intracellularly, in endosomes. Both enzymes catalyze the formation of both cADP-ribose and NAADP, as well as the glycohydrolase reaction. The cyclase reaction predominates at neutral pH, and the nicotinamide/nicotinic acid exchange reaction at acid pH, suggesting that in cytosol the main product of the soluble enzyme is cADP-ribose. In endosomes,... 

Azaperone, brompheniramine, chlorphenir amine, isoniazid, metyrapone, nicametate, nicotinamide, nicotine, nicotinic acid, nifenazone, nikethamide, pheniramine, xanthinol nicotinate... 

Adverse effects do not occur with standard doses of nicotinamide. Nicotinic acid, which is converted into nicotinamide, causes peripheral vasodilatation accompanied by an unpleasant flushing and itching, and the patient may faint. 

The potential of PBI LC-MS in the analysis of various vitamins was explored by Careri et al. [99-100]. The fat-soluble vitamins A, D, and E were analysed in food and multivitamin preparations [99]. Absolute detection limits in SIM mode were 0.6-25 ng after fast leversed-phase separation using a 97% aqueous methanol as mobile phase. Mass spectra in El, positive-ion and negative-ion Cl were obtained and discussed. The mass-spectral and quantitative performance of PBI LC-MS in the analysis of eleven water-soluble vitamins was also explored [100]. Detection limits were determined in SIM mode under positive-ion Cl, and were below 15 ng for ascorbic acid, nicotinamide, nicotinic acid, and pyridoxal, around 100 ng for dehydroascorbic acid, panthothenic acid, and thiamine, and above 200 ng for biotin, pyridoxamime, and pyridoxine. Riboflavine was not detected. 

Niacinamide, U5P. Niacinamide, nicotinamide, nicotinic acid amide, is prepared by the amidation of esters of nicotinic acid or by pa.ssing ammonia gas into nicotinic acid at 320°C. Nicotinamide is a white cry.stalline powder that is odorless, or nearly so, and bitter. One gram is soluble in about I mL of water, I.S mL of alcohol, and about 10 mL of glycerin. Aqueous solutions aie neutral to litmus. For occurrence, action, and uses, see nicotinic acid. Niacinamide has pK values of O.. and 3.35. 

Simple pyridine, pyrazine, and pyrrolo derivatives have been described from many different types of arthropods. Nicotine (177), nicotinamide, nicotinic acid, 2-pyrrolidone, N-methylpyrrolididone (178), 8-hydroxyquinoline (179), and 2-isobutyl-3-methoxypyrazine (180) have been detected in the defensive secretion and blood of larvae of the moth Lymantria dispar The nicotine isomer anabasine (181) and its congener anabaseine (182) have been identified as venom components in several ant species,whereas... 

The order of their effectiveness as photosensitizers for the oxidation of glycyltryptophan in aqueous solution is nicotinic acid > nicotinamide > nicotine-hydroxymethylamide these reactions seems to involve the superoxide radical anion. 

Nicotinic acid and its derivatives are stable to oxidation by heat, light, acid or alkali and this means that extraction into solvent systems compatible with HPLC is relatively easy by comparison with other vitamins. Biological extracts are readily prepared by deproteini-sation with acetone followed by extraction with dilute hydrochloric acid alternatively, ethyl acetate in combination with hydrochloric acid may be used to extract samples. The most popular HPLC mode for the separation of nicotinic acid is reversed phase ion-pair chromatography. For example, using a fiBondapak Cjg column with a mobile phase of water-methanol (9 1) plus 0.05 M tetrabutylam-monium phosphate as the ion-pair reagent, nicotinamide-A-oxide, 2-hydroxypyridine-5-carboxylic acid, nicotinamide, nicotinic acid and nicotinuric acid were consecutively eluted (Hengen et al., 1978). 

CAS 98-92-0 EINECS/ELINCS 202-713-4 Synonyms Nicotinamide Nicotine acid amide Nicotinic acid amide Nicotinic amide Nicotylamidel... 

Fig. 1. NAD content of CF-3 cells incubated in Ca + depleted medium O— O), Ca + supplemented medium ( - ), and Ca + depleted medium supplemented with normal levels of Ca + (1.8 mM) after 2 hr of incubation (x—x). Arrow indicates time of Ca + addition. Values are Mean SEM for three experiments. Ca + depleted medium was McCoy s 5a prepared without nicotinamide, nicotinic acid, and CaCl2. It was supplemented with 10% FBS treated as described (14). NAD determinations were performed as described (14). Reprinted with permission from ref. 14.

Quinolinate decarboxylation and conversion to nicotinic acid mononucleotide is catalysed by quinolinate phosphoribosyltransferase, a rate-limiting enzyme in the conversion of tryptophan to NAD the reaction requires Mg and is negatively regulated by nicotinamide. Next the transfer of adenylate from ATP by an intermediate of nicotinamide/nicotinate-mononucleotide-adenyl-transferases isoenzymes (NMNAT, see below) yields nicotinic acid adenine... 

Figure 7.3 NAD recycling. Humans have two metabolic pathways that are able to recycle nicotinamide. NAD-consuming enzymes (ARTs, PARPs, sirtuins) break down NAD to nicotinamide and ADP-ribosyl product. Nicotinamide by the enzymatic action of nicotinamide phosphoribosyltransferase (NAMP/PBEF) and nicotinamide/nicotinate-mononucleotide-adenyltransferases isoenzymes (NMATl-3) is then retransformed to NAD. In a second pathway, nicotinamide riboside is phosphorylated by nicotinamide riboside kinase (NRK 1,2) to nicotinamide mononucleotide. Subsequently, nicotinamide mononucleotide is converted to NAD by the catalytic action of NMNATs.

Nicotinic acid (3-pyridine carboxylic acid or niacin) nicotinamide (nicotinic acid amide), niacinamide, 3-pyridine-carboxylic acid amide Thiamines, hydroxy-ethylthiamine... 

Figure 1 Structures of nicotinamide, nicotinic acid, and related compounds.

NAD is biosynthesized via four pathways as shown in Figure 2 (I) nicotinic acid NaMN —> NaAD —> NAD (II) nicotinamide —> NMN — NAD (III) nicotinamide nicotinic acid -> NaMN NaAD -> NAD+ (IV) quinolinic acid — NaMN —> NaAD NAD. In the four NAD biosynthetic pathways, pathways II and IV are physiologically important. Quinolinic acid is synthesized... 

Py (III) NAD nicotinamide — nicotinamide A(-oxide (IV) NAD —> nicotinamide nicotinic acid — nicotinuric acid (V) NAD —> nicotinamide nicotinic acid V -methylnicotinic acid (trigonelline). In rats, pathway II mainly functions, and in humans pathway I. Pathway V functions in mushrooms, shellfish, and plants, but not in mammals. 

TS Agostini, HT Godoy. Simultaneous determination of nicotinamide, nicotinic acid, riboflavin, thiamin, and pyridoxine in eiuiched Brazilian foods by HPLC. J High Resol Chromatogr 20 245-248, 1997. 

Niacin refers to a group of compoimds also known as vitamin B3, presenting similar biological activity, including nicotinamide, nicotinic acid, as well as other pyridine nucleotide structures. In the body, these compounds act as cofactors in oxidation—reduction reactions. To determine the total vitamin B3 content, either an acid or alkaline hydrolysis is necessary. The separation is normally performed by RPLC with fluorescence (322 nm ex., 380 nm em.) or UV detection (254 nm). 

---