RESUMEN
BACKGROUND: ß-nicotinamide mononucleotide stands out as an essential breakthrough in "anti-aging" and consistently leads the list of top-selling nutritional supplements in terms of quantity. As the metabolites of ß-nicotinamide mononucleotide, the detection of nicotinamide and N1-methylnicotinamide is of great significance for evaluating the nutritional effect of dietary supplements of ß-nicotinamide mononucleotide. However, due to the extremely low concentration of nicotinamide and N1-methylnicotinamide in vivo and the serious matrix interference in biological samples, there is an increasing demand for materials and methods of pre-treatment. RESULTS: In this study, Fe3O4@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid magnetic fluid was synthesized for the first time, and it was used as pretreatment material to detect nicotinamide and N1- methylnicotinamide in urine samples by high performance liquid chromatography. Compared with other adsorption materials, Fe3O4@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid nanoparticles are a kind of uniform magnetic fluid. Furthermore, they have more types and quantities of interaction sites (electrostatic interactions, hydrophobic interactions, hydrogen bonding interactions, and π-π interactions), so they own greater adsorption capacity. When the pH of the solution is 4, they can be adsorbed quickly within 10 s. The method successfully detected trace nicotinamide and N1-methylnicotinamide in urine samples in the linear range of 0.1-80 µg mL-1, the low detection limits were 0.30 ng mL-1 and 1.5 ng mL-1 respectively, and the quantification limits were 1.0 ng mL-1 and 5.0 ng mL-1, respectively. At the same time, the standard urine samples of nicotinamide and N1-methylnicotinamide showed satisfactory recovery rate 94.50-109.1 %. The results indicated that the established method can accurately and quantitatively determine trace nicotinamide and N1-methylnicotinamide in urine samples. SIGNIFICANCE: Consequently, low concentration of ß-nicotinamide mononucleotide metabolites can be detected simultaneously, and the interference can be eliminated during the detection process, which provides an efficient and convenient pretreatment method and a rapid and sensitive detection method for the analysis of ß-nicotinamide mononucleotide metabolites. What's more, it has a wide application prospect in the analysis of other similar metabolites in biological samples.
Asunto(s)
Niacinamida , Mononucleótido de Nicotinamida , Mononucleótido de Nicotinamida/química , Mononucleótido de Nicotinamida/orina , Mononucleótido de Nicotinamida/metabolismo , Humanos , Niacinamida/orina , Niacinamida/análogos & derivados , Niacinamida/metabolismo , Niacinamida/análisis , Niacinamida/química , Cromatografía Líquida de Alta Presión , Nanopartículas de Magnetita/química , Adsorción , Límite de DetecciónRESUMEN
After toxicological studies with nitrate/nitrite in rats it was observed with nuclear magnetic resonance that N-methylnicotinamide (NMN), a metabolite of tryptophan was increased. The use of NMN as a biomarker for nitrate/nitrite exposure was investigated further in additional experiments with rats and in a human study with volunteers. Rats have been exposed to 36 mmol KCl, KNO2 or KNO3 per 1 tap water for 13 weeks. In general, the animals receiving KNO2 showed a statistically significant (P < 0.01) 2-fold increase in NMN compared with the KCl group. This increase was observed after a relatively high exposure (about 800 mg/kg body wt./day). It was also noticed that the initial increase in urinary NMN concentrations decreased after prolonged exposure for 12 weeks. To investigate the induction of urinary NMN in humans, an experiment has been performed in which 8 volunteers received a single oral dose of sodium nitrate, corresponding with 10 mg NaNO3/kg body wt./day (2 times the acceptable daily intake for nitrate). A rapid increase of urinary NMN (up to 6-fold) was observed in 4 volunteers. In the other 4 volunteers the urinary NMN concentration did hardly react. When the experiment was repeated with the same volunteers, it was remarkable to see that in this experiment all volunteers showed the same individual response on urinary NMN as in the first experiment. It is concluded that NMN can possibly be a good biomarker for the internal nitrite exposure of humans, but further studies are necessary to assess its value.
Asunto(s)
Biomarcadores/orina , Monitoreo del Ambiente/métodos , Contaminantes Ambientales/efectos adversos , Niacinamida/análogos & derivados , Mononucleótido de Nicotinamida/orina , Nitratos/efectos adversos , Nitratos/orina , Animales , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Masculino , Niacinamida/orina , Nitratos/metabolismo , Nitritos/metabolismo , Nitritos/orina , Ratas , Ratas EndogámicasRESUMEN
Male rats were exposed to manganese sulphate i.p. daily for a period of four weeks to see its effects on tissue levels and urinary excretion of total nicotinamide nucleotides (TNN). Increased levels of TNN were observed in blood and brain while the levels were found to be decreased in liver. There was a progressive increase in the excretion of TNN during the experimental period. TNN levels in blood and urine might serve as useful biological indicators of Mn toxicity.