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
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| 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
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| Solubility = 1 g/ 14.5 L @ 16 °C<br>1 g/1.4 L @ 100 °C
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| Section7 = {{Chembox Hazards
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}}
'''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]]