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In vivo evaluation of CYP1A2 CYP2A6, NAT-2 and xanthine oxidase activities in a Greek population sample by the RP-HPLC monitoring of caffeine metabolic ratios
dc.creator | Begas, E. | en |
dc.creator | Kouvaras, E. | en |
dc.creator | Tsakalof, A. | en |
dc.creator | Papakosta, S. | en |
dc.creator | Asprodini, E. K. | en |
dc.date.accessioned | 2015-11-23T10:23:42Z | |
dc.date.available | 2015-11-23T10:23:42Z | |
dc.date.issued | 2007 | |
dc.identifier | 10.1002/bmc.736 | |
dc.identifier.issn | 0269-3879 | |
dc.identifier.uri | http://hdl.handle.net/11615/26220 | |
dc.description.abstract | A RP-HPLC method was developed for the assessment of caffeine and its metabolites in urine and was used for the evaluation of the CYP1A2, CYP2A6, xanthine oxidase (XO) and N-acetyl-transferase-2 (NAT-2) in vivo activities in 44 Greek volunteers (21 men, 23 women). Spot urine samples were analyzed 6 h after 200 mg caffeine consumption, following a 30 h methylxantine-free diet. The major urinary caffeine metabolites are 1-methyluric acid (1U), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 1-methylxanthine (1X), 1,7-dimethyluric acid (17U) and 1,7-dimethylxanthine (17X). CYP1A2, CYP2A6, XO and NAT-2 activities were estimated from the metabolic ratios (AFMU + 1U + 1X)/17U, 17U/17X, 1U/(1X + 1U) and AFMU/(AFMU + 1U + 1X), respectively. Metabolites and internal standard were extracted with chlorofonn/isopropanol (85:15, v/v) and separated on a C-18 column by an isocratic HPLC system using a two-step elution with manual switch from solvent A (0.1% acetic acid-methanol-acetonitrile, 92:4:5 v/v) to solvent B (0.1% acetic acid-methanol, 60:40, v/v), and detected at 280 nm. The method exhibited adequate metabolite separation (resolution factors > 1.48), accuracy (94.1-106.3%) and intraday and interclay precision < 8.02 and < 8.78%, respectively (n = 6). Smoking affected only CYP1A2, whereas gender had no effect in any enzyme activity. NAT-2 exhibited bimodal distribution, 63.6% of volunteers being slow acetylators. The developed RP-HPLC method was fully validated and successfully applied for the evaluation of CYP1A2, CYP2A6, XO and NAT-2 activities. Copyright (c) 2007 John Wiley & Sons, Ltd. | en |
dc.source | Biomedical Chromatography | en |
dc.source.uri | <Go to ISI>://WOS:000244218800010 | |
dc.subject | CYP1A2 | en |
dc.subject | CYP2A6 | en |
dc.subject | XO | en |
dc.subject | NAT-2 | en |
dc.subject | HPLC | en |
dc.subject | caffeine | en |
dc.subject | PERFORMANCE LIQUID-CHROMATOGRAPHY | en |
dc.subject | HUMAN-LIVER-MICROSOMES | en |
dc.subject | BLADDER-CANCER-RISK | en |
dc.subject | N-ACETYLTRANSFERASE | en |
dc.subject | EXTRACTIONLESS METHOD | en |
dc.subject | MASS-SPECTROMETRY | en |
dc.subject | ENZYME-ACTIVITY | en |
dc.subject | URINE | en |
dc.subject | PHENOTYPE | en |
dc.subject | OXIDATION | en |
dc.subject | Biochemical Research Methods | en |
dc.subject | Biochemistry & Molecular Biology | en |
dc.subject | Chemistry, Analytical | en |
dc.subject | Pharmacology & Pharmacy | en |
dc.title | In vivo evaluation of CYP1A2 CYP2A6, NAT-2 and xanthine oxidase activities in a Greek population sample by the RP-HPLC monitoring of caffeine metabolic ratios | en |
dc.type | journalArticle | en |
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