Xanthine 52432 226163098 2008-07-17T02:51:07Z 98.160.152.216 /* Clinical significance of xanthine derivatives */ Fixed subscripts to superscripts, fixed capitalization - MrX_TLO {{distinguish|xanthene}} {{chembox new | reference = <ref>''Merck Index'', 11th Edition, '''9968'''.</ref> | ImageFile = Xanthin - Xanthine.svg | ImageSize = | IUPACName = 3,7-Dihydro-purine-2,6-dione | OtherNames = 1''H''-Purine-2,6-diol | Section1 = {{Chembox Identifiers | Abbreviations = | CASNo = 69-89-6 | EINECS = | PubChem = 1188 | SMILES = O=C1NC(=O)c2[nH]cnc2N1 | InChI = | RTECS = | MeSHName = | ChEBI = | KEGG = | ATCCode_prefix = | ATCCode_suffix = | ATC_Supplemental =}} | Section2 = {{Chembox Properties | Formula = C<sub>5</sub>H<sub>4</sub>N<sub>4</sub>O<sub>2</sub> | MolarMass = 152.111 g/mol | Appearance = White solid | Density = | MeltingPt = decomposes | Melting_notes = | BoilingPt = | Boiling_notes = | Solubility = 1 g/ 14.5 L @ 16 °C<br>1 g/1.4 L @ 100 °C | SolubleOther = | Solvent = | pKa = | pKb = }} | Section7 = {{Chembox Hazards | EUClass = | EUIndex = | MainHazards = | NFPA-H = | NFPA-F = | NFPA-R = | NFPA-O = | RPhrases = | SPhrases = | RSPhrases = | FlashPt = | Autoignition = | ExploLimits = | PEL = }} }} '''Xanthine''' ({{IPAEng|ˈzænθiːn, ˈzænθaɪn]}}), (3,7-dihydro-purine-2,6-dione), is a [[purine]] [[base (chemistry)|base]] found in most body tissues and fluids and in other organisms. ==Reactions== Xanthine is a product on the pathway of [[purine degradation]]. * It is created from [[guanine]] by [[guanine deaminase]]. * It is created from [[hypoxanthine]] by [[xanthine oxidoreductase]]. Xanthine is subsequently converted to [[uric acid]] by the action of the [[xanthine oxidase]] enzyme. ==Pathology== People with the rare [[genetic disorder]] [[xanthinuria]] lack sufficient xanthine oxidase and cannot convert xanthine to uric acid. ==Clinical significance of xanthine derivatives== Derivatives of xanthine, known collectively as '''xanthines''', are a group of [[alkaloid]]s commonly used for their effects as mild [[stimulant]]s and as [[bronchodilator]]s, notably in treating the symptoms of [[asthma]]. In contrast to other, more potent stimulants, they only inhibit the actions of sleepiness-inducing [[adenosine]], making them somewhat less effective as stimulants than [[sympathomimetic amine]]s. Due to widespread effects, the [[therapeutic range]] of '''xanthines''' is narrow, making them merely a second-line asthma treatment. The therapeutic level is 10-20 micrograms/mL blood; signs of toxicity include tremor, nausea, nervousness, and tachycardia/arrhythmia. [[Methylation|Methylated]] xanthine derivatives include [[caffeine]], [[paraxanthine]], [[theophylline]], and [[theobromine]]. [[Image:Xanthine-base.JPG‎|226px|left|thumb|Caffeine: R<sub>1</sub> = R<sub>2</sub> = R<sub>3</sub> = CH<sub>3</sub>, Theobromine: R<sub>1</sub> = H, R<sub>2</sub> = R<sub>3</sub> = CH<sub>3</sub>], Theophylline: R<sub>1</sub> = R<sub>2</sub> = CH<sub>3</sub>, R<sub>3</sub> = H]] These drugs [[phosphodiesterase inhibitor|inhibit phosphodiesterase]] and [[receptor antagonist|antagonise]] [[adenosine]]. Xanthines are also found very rarely as constituents of [[nucleic acid]]s. {| class="wikitable sortable" |+ Selected Xanthines !Name!!R<sup>1</sup>!!R<sup>2</sup>!!R<sup>3</sup>!![[IUPAC nomenclature]]!!Found In |- |[[Caffeine]]||[[Methyl|CH<sub>3</sub>]]||[[Methyl|CH<sub>3</sub>]]||[[Methyl|CH<sub>3</sub>]]||1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione||[[Coffee]], [[Guarana]], [[Yerba mate]], [[Tea]] |- |[[Theobromine]]||H||[[Methyl|CH<sub>3</sub>]]||[[Methyl|CH<sub>3</sub>]]||3,7-dihydro-3,7-dimethyl-1H-purine-2,6-dione||[[Chocolate]] |- |[[Theophylline]]||[[Methyl|CH<sub>3</sub>]]||[[Methyl|CH<sub>3</sub>]]||H||1,3-dimethyl-7H-purine-2,6-dione||[[Tea]] |- |[[Xanthine]]||H||H||H||3,7-dihydro-purine-2,6-dione||plants, animals |- |-class="sortbottom" !Name!!R<sup>1</sup>!!R<sup>2</sup>!!R<sup>3</sup>!![[IUPAC nomenclature]]!!Found In |} ==References== {{Reflist}} ==See also== * [[Murchison meteorite]] {{Psychostimulants, agents used for ADHD and nootropics}} {{Asthma and copd rx}} {{Nucleotide metabolism intermediates}} [[Category:Imidazoles]] [[Category:Xanthines| ]] [[da:Xanthin]] [[de:Xanthin]] [[es:Xantina]] [[fr:Xanthine]] [[nl:Xanthine]] [[it:Xantina]] [[ja:キサンチン]] [[pl:Ksantyna]] [[pt:Xantina]] [[fi:Ksantiini]] [[sv:Xantin]] [[zh:黄嘌呤]]