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Skeletal formula of paraxanthine
Ball-and-stick model of the paraxanthine model
IUPAC name
Other names
1 ,7-Dimethylxanthine
3D model (JSmol)
ECHA InfoCard 100.009.339
Molar mass 180.17 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).
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Infobox references

Paraxanthine, or 1,7-dimethylxanthine, is a dimethyl derivative of xanthine, structurally related to caffeine. Like caffeine, paraxanthine is a psychoactive central nervous system (CNS) stimulant. It possesses a potency roughly equal to that of caffeine and is likely involved in the mediation of the effects of caffeine itself.

Production and metabolism[edit]

Paraxanthine is not produced by plants[citation needed] and is only observed in nature as a metabolite of caffeine in animals. After intake, roughly 84% of caffeine is demethylated at the 3-position to yield paraxanthine, making it the chief metabolite of caffeine in the body.[1]

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]

Physiological effects[edit]

Paraxanthine has a number of physiological effects on animals:


Paraxanthine is believed to exhibit a lower toxicity than caffeine.[10] While blood levels commensurate with average intake appear to be fairly innocuous, high blood concentrations of paraxanthine have been linked to miscarriage in pregnant mothers.[11]


  1. ^ Guerreiro S, Toulorge D, Hirsch E, Marien M, Sokoloff P, Michel PP (October 2008). "Paraxanthine, the primary metabolite of caffeine, provides protection against dopaminergic cell death via stimulation of ryanodine receptor channels". Mol. Pharmacol. 74 (4): 980–9. doi:10.1124/mol.108.048207. PMID 18621927.
  2. ^ Essayan DM. (2001). "Cyclic nucleotide phosphodiesterases". J Allergy Clin Immunol. 108 (5): 671–80. doi:10.1067/mai.2001.119555. PMID 11692087.
  3. ^ Deree J, Martins JO, Melbostad H, Loomis WH, Coimbra R (2008). "Insights into the Regulation of TNF-α Production in Human Mononuclear Cells: The Effects of Non-Specific Phosphodiesterase Inhibition". Clinics (Sao Paulo). 63 (3): 321–8. doi:10.1590/S1807-59322008000300006. PMC 2664230. PMID 18568240.
  4. ^ Marques LJ, Zheng L, Poulakis N, Guzman J, Costabel U (February 1999). "Pentoxifylline inhibits TNF-alpha production from human alveolar macrophages". Am. J. Respir. Crit. Care Med. 159 (2): 508–11. doi:10.1164/ajrccm.159.2.9804085. PMID 9927365.
  5. ^ a b Peters-Golden M, Canetti C, Mancuso P, Coffey MJ (2005). "Leukotrienes: underappreciated mediators of innate immune responses". J. Immunol. 174 (2): 589–94. doi:10.4049/jimmunol.174.2.589. PMID 15634873.
  6. ^ Daly JW, Jacobson KA, Ukena D (1987). "Adenosine receptors: development of selective agonists and antagonists". Prog Clin Biol Res. 230 (1): 41–63. PMID 3588607.
  7. ^ Hetzler RK, Knowlton RG, Somani SM, Brown DD, Perkins RM (January 1990). "Effect of paraxanthine on FFA mobilization after intravenous caffeine administration in humans (Bethesda MD 1985)". Journal of Applied Physiology. 68 (1): 44–47. doi:10.1152/jappl.1990.68.1.44. PMID 2312486.
  8. ^ Hawke TJ, Willmets RG, Lindinger MI (November 1999). "K+ transport in resting rat hind-limb skeletal muscle in response to paraxanthine, a caffeine metabolite". Canadian Journal of Physiology and Pharmacology. 77 (11): 835–843. doi:10.1139/y99-095. PMID 10593655.
  9. ^ Hawke TJ, Allen DG, Lindinger MI (December 2000). "Paraxanthine, a caffeine metabolite, dose dependently increases [Ca(2+)](i) in skeletal muscle". Journal of Applied Physiology. 89 (6): 2312–2317. doi:10.1152/jappl.2000.89.6.2312. PMID 11090584.
  10. ^ Neal L. Benowitz; Peyton Jacob; Haim Mayan; Charles Denaro (1995). "Sympathomimetic effects of paraxanthine and caffeine in humans". Clinical Pharmacology & Therapeutics. 58 (6): 684–691. doi:10.1016/0009-9236(95)90025-X.
  11. ^ Mark A. Klebanoff; Richard J. Levine; Rebecca DerSimonian.; John D. Clemens; Diana G. Wilkins (1999). "Maternal Serum Paraxanthine, a Caffeine Metabolite, and the Risk of Spontaneous Abortion". New England Journal of Medicine. 341 (22): 1639–1644. doi:10.1056/NEJM199911253412202. PMID 10572151.

External links[edit]