+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Identification of N1-methyl-2-pyridone-5-carboxamide and N1-methyl-4-pyridone-5-carboxamide as components in urine extracts of individuals consuming coffee

, : Identification of N1-methyl-2-pyridone-5-carboxamide and N1-methyl-4-pyridone-5-carboxamide as components in urine extracts of individuals consuming coffee. Journal of Pharmaceutical and Biomedical Analysis 30(3): 773-780

Caffeine metabolites were extracted from urine samples collected 4 h after consumption of a cup of coffee and were separated by high-performance liquid chromatography (HPLC) on a C18 (5 microm) reverse-phase column using an acetonitrile (5%), acetic acid (0.05%) solution as the mobile phase. The elution profiles indicated the constant presence of a major and a minor components eluting between the caffeine metabolites 5-acetamido-6-formyl-3-methyluracil (AFMU) and 7-methylxanthine (7X) in an approximate nine. A procedure was developed for the isolation of the major component in an apparent pure form, and the yield was 10-20 mg from 400 ml of urine. The minor component was isolated in an apparent pure form by this procedure as well, and the yield was 0.5 mg from 200 ml of urine. The average ratio of the two components in urine, UV absorption and 1H-NMR spectra of the two components, and 13C-NMR spectrum, mass spectrum and elemental analysis of the major component identified the major and minor components as N(1)-methyl-2-pyridone-5-carboxamide and N(1)-methyl-4-pyridone-5-carboxamide, respectively, two major metabolites of the vitamin niacin present in a significant amount in coffee beans. The two metabolites were present in the same average amount in urine extracts of individuals irregardless of coffee consumption. The findings are briefly discussed in relation to the nutritional sources of niacin and to current procedures for measuring amounts of the two metabolites in urine samples.


PMID: 12367703

DOI: 10.1016/s0731-7085(02)00384-9

Other references

Alnot, J.Y.; Frajman, J.M.; Bocquet, L., 1990: Primary total aseptic osteonecrosis of the scaphoid bone. Apropos of 3 cases. Idiopathic avascular necrosis of the all scaphoid bone is uncommon. We report 3 cases treated by resection of the first row of the carpal bone. Scintigraphy, CT-scan, magnetic resonance imaging are helpful for the diagnostic.

Day, D.; Sarkar, D., 1985: Dextran analysis of raw sugar--an alternative method. International sugar journal 87(1039): 123-126

Bickenbach, W., 1955: Proposals for a clinical classification of carcinoma of the uterus. Zentralblatt für Gynakologie 77(47): 1845-1849

Steeds, L.; Rowe, K.; Dowker, A., 1997: Deaf children's understanding of beliefs and desires. Twenty-two children (5-12 year old) who were profoundly, prelingually deaf were given two tests designed to tap their 'theory of mind', that is, their ability to attribute independent mental states to other people. The tests were version...

Chiu, C.J.; Mersereau, W.A.; Scott, H.J., 1972: Subendocardial hemorrhagic necrosis. The role of direct mechanical trauma on the endocardium. Journal of Thoracic and Cardiovascular Surgery 64(1): 66-75

Marsh, S.G., 1998: Nomenclature for factors of the HLA system, update February 1998. WHO Nomenclature Committee for Factors of the HLA System. Tissue Antigens 51(5): 584-585

Kisdi, E.; Meszena, G., 1995: Life Histories with Lottery Competition in a Stochastic Environment: ESSs which Do Not Prevail. We present examples for multiple ESSs, for ESSs which cannot invade other established strategies, and for ESSs which cannot be approached gradually in a lottery model with randomly fluctuating adult survival. In case of multiple ESSs the outcome o...

Fritz, S.; See, L.; van der Velde, M.; Nalepa, R.A.; Perger, C.; Schill, C.; McCallum, I.; Schepaschenko, D.; Kraxner, F.; Cai, X.; Zhang, X.; Ortner, S.; Hazarika, R.; Cipriani, A.; D.B.lla, C.; Rabia, A.H.; Garcia, A.; Vakolyuk, M'yana.; Singha, K.; Beget, M.E.; Erasmi, S.; Albrecht, F.; Shaw, B.; Obersteiner, M., 2013: Downgrading recent estimates of land available for biofuel production. Recent estimates of additional land available for bioenergy production range from 320 to 1411 million ha. These estimates were generated from four scenarios regarding the types of land suitable for bioenergy production using coarse-resolution inpu...

Sanagi M.M., 1988: Retention indices in supercritical fluid chromatography on a polystyrene divinylbenzene column. Chromatographia: 84

Russell, C.; Griffin, C.; Flinchbaugh, C.; Martin, M.; Atilano, R., 1985: Coping strategies associated with intergenerational transfer of the family farm. Five strategies for coping with the stress created by the intergenerational transfer of the family farm were identified in a population of midwestern families. These strategies were then associated with measures of psychological well being and pe...