xanthine

[zan-theen, -thin]
noun Biochemistry, Chemistry.
  1. a crystalline, nitrogenous compound, C5H4N4O2, related to uric acid, occurring in urine, blood, and certain animal and vegetable tissues.
  2. any derivative of this compound.

Origin of xanthine

From French, dating back to 1855–60; see origin at xantho-, -ine2
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British Dictionary definitions for xanthine

xanthine

noun
  1. a crystalline compound related in structure to uric acid and found in urine, blood, certain plants, and certain animal tissues. Formula: C 5 H 4 N 4 O 2
  2. any substituted derivative of xanthine, esp one of the three pharmacologically active methylated xanthines, caffeine, theophylline, or theobromine, which act as stimulants and diuretics
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

xanthine in Medicine

xanthine

[zănthēn′, -thĭn]
n.
  1. A yellowish-white crystalline purine base that is a precursor of uric acid and is found in blood, urine, and muscle tissue.
  2. Any of several derivatives of this compound.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

xanthine in Science

xanthine

[zănthēn′, -thĭn]
  1. Any of various purines having two oxygen atoms attached to the six-member ring of carbon and nitrogen atoms. Xanthines include caffeine, theophylline (a toxic alkaloid found in tea leaves), and theobromine (a toxic alkaloid found in cocoa).
  2. The simplest of this class of compounds, forming yellowish-white crystals. It is produced in the body as an intermediate stage in the breakdown of purines to uric acid. It is also found in blood and in certain plants. Chemical formula: C5H4N4O2.
  3. Any of several derivatives of this compound.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.