Topic
Xanthine
About: Xanthine is a research topic. Over the lifetime, 4046 publications have been published within this topic receiving 129820 citations. The topic is also known as: Xanthine.
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TL;DR: It is demonstrated that after in vitro oxidant injury, lymphocytes may have alterations in the cell membrane and impaired function.
39 citations
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TL;DR: In this article, the authors present resonant two-photon ionization and IR-UV double resonance spectra of methylated xanthine derivatives including 7-methylxanthine, theophylline and theobromine monomer, seeded in a supersonic jet by laser desorption.
Abstract: We present resonant two-photon ionization and IR–UV double resonance spectra of methylated xanthine derivatives including 7-methylxanthine dimer and theobromine dimer seeded in a supersonic jet by laser desorption. For 7-methylxanthine, theophylline and theobromine monomer we assign the lowest energy tautomer based on comparison with IR–UV double resonance spectra and calculated IR frequencies. For the 7-methylxanthine dimer, we observe hydrogen bonding on the N3H position suggesting 3 possible combinations, one that is reverse Watson–Crick type and two that are reverse Hoogsteen type. For the theobromine dimer, we observe a stacked structure. For trimethylxanthine dimers we infer a stacked structure as well.
39 citations
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TL;DR: The methodology for the unequivocal identification of caffeine and 13 possible metabolites (mono, di- and tri-N-methylated xanthine and uric acid derivatives) based on TLC, UV and mass spectrometry has been developed.
39 citations
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TL;DR: Nimesulide was more active than its metabolites in preventing OH·-induced depolymerisation of hyaluronic acid, with a 50% effective concentration of approximately 230 μmol/L, which was fairly comparable to that of tenoxicam.
Abstract: The antioxidant activity of nimesulide and its main metabolites, 4′-hydroxynimesulide (M1) and 2-(4′-hydroxyphenoxy)-4-N-acetylamino-methansulfonanilide (M2), was investigated using 2 in vitro models: NADPH-supported lipid peroxidation in rat liver microsomes (marker MDA formation) and xanthine/xanthine oxidase, iron-promoted depolymerisation of hyaluronic acid, determined by gel permeation Chromatographic analysis (marker molecular weight distribution). In the lipid peroxidation model, all the compounds inhibited MDA formation in a concentrationdependent manner, although with different potencies; the maximum scavenging effect was observed for M1 [50% inhibitory concentration (IC50) = 30 μmol/L; M2 IC50 = 0.5 mmol/L; nimesulide = 0.8 mmol/L].
39 citations
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TL;DR: A series of polymethoxyflavones isolated and hemisynthesized from the bud exudates of Gardenia oudiepe has been evaluated for in-vitro XO inhibitory activity and promising results are suggested, suggest the use of these compounds as potential leads for the design and development of novel XO inhibitors.
39 citations