Paraxanthine

Paraxanthine

Names
IUPAC name 1,7-Dimethyl-3H-purine-2,6-dione
Other names Paraxanthine, 1,7-Dimethylxanthine
Identifiers
CAS Number	611-59-6 N
3D model ( JSmol )	Interactive image
ChEBI	CHEBI:25858 Y
ChEMBL	ChEMBL1158 Y
ChemSpider	4525 Y
ECHA InfoCard	100.009.339
PubChem CID	4687
UNII	Q3565Y41V7 Y
CompTox Dashboard (EPA)	DTXSID2052281
InChI InChI=1S/C7H8N4O2/c1-10-3-8-5-4(10)6(12)11(2)7(13)9-5/h3H,1-2H3,(H,9,13) Y Key: QUNWUDVFRNGTCO-UHFFFAOYSA-N Y InChI=1/C7H8N4O2/c1-10-3-8-5-4(10)6(12)11(2)7(13)9-5/h3H,1-2H3,(H,9,13) Key: QUNWUDVFRNGTCO-UHFFFAOYAS
SMILES O=C2Nc1ncn(c1C(=O)N2C)C
Properties
Chemical formula	C7H8N4O2
Molar mass	180.167 g·mol−1
Melting point	351 to 352 °C (664 to 666 °F; 624 to 625 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Paraxanthine, also known as 1,7-dimethylxanthine, is an isomer of

Paraxanthine is not known to be produced by plants[1] but is observed in nature as a metabolite of caffeine in animals and some species of bacteria.^[2]

Paraxanthine is the primary metabolite of caffeine in humans and other animals, such as mice.

Certain proposed synthetic pathways of caffeine make use of paraxanthine as a bypass intermediate. However, its absence in plant alkaloid assays implies that these are infrequently, if ever, directly produced by plants.^{[citation needed]}

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Like caffeine, paraxanthine is a

Studies indicate that, similar to caffeine, simultaneous antagonism of adenosine receptors^[9] is responsible for paraxanthine's stimulatory effects. Paraxanthine adenosine receptor binding affinity (21 μM for A1, 32 μM for A2_A, 4.5 μM for A2_B, and >100 for μM for A3) is similar or slightly stronger than caffeine, but weaker than theophylline.^[10]

Paraxanthine is a selective inhibitor of cGMP-preferring phosphodiesterase (PDE9) activity^[11] and is hypothesized to increase glutamate and dopamine release by potentiating nitric oxide signaling.^[12] Activation of a nitric oxide-cGMP pathway may be responsible for some of the behavioral effects of paraxanthine that differ from those associated with caffeine.^[13]

Paraxanthine is a competitive nonselective

Unlike caffeine, paraxanthine acts as an enzymatic effector of Na⁺/K⁺ ATPase. As a result, it is responsible for increased transport of potassium ions into skeletal muscle tissue.^[18] Similarly, the compound also stimulates increases in calcium ion concentration in muscle.^[19]

The

Paraxanthine is a phosphodiesterase type 9 (PDE9) inhibitor and it is sold as a research molecule for this same purpose.^[21]

Paraxanthine is believed to exhibit a lower toxicity than caffeine and the caffeine metabolite, theophylline.^[22][23] In a mouse model, intraperitoneal paraxanthine doses of 175 mg/kg/day did not result in animal death or overt signs of stress;^[24] by comparison, the intraperitoneal _LD50 for caffeine in mice is reported at 168 mg/kg.^[25] In in vitro cell culture studies, paraxanthine is reported to be less harmful than caffeine and the least harmful of the caffeine-derived metabolites in terms of hepatocyte toxicity.^[26]

As with other methylxanthines, paraxanthine is reported to be

Paraxanthine was reported to be significantly less clastogenic compared to caffeine or theophylline in an in vitro study using human lymphocytes.^[28]