Xanthine alkaloids (xanthines) are purine bases found in body tissues and
fluids and in some plants. They are probably the most widely known and used
alkaloids, being constituents of popular daily beverages tea and coffee.
Xanthine alkaloids include:
- Xanthinol Niacinate
- Uric Acid
Xanthine alkaloid is a purine base found in most body tissues and
fluids, certain plants, and some urinary calculi. It is an intermediate in the
degradation of adenosine monophosphate (AMP) to uric acid, being formed by
oxidation of hypoxanthine.
Caffeine, theophylline, and theobromine alkaloids are
methylated xanthine derivatives; they differ only in the number and position of
methyl substituents around the xanthine ring system. Caffeine alkaloid is a CNS
stimulant. It is also a diuretic and is used in combination with analgesics.
Theophylline and theobromine are minor alkaloids of tea; theobromine also occurs
in cocoa. Caffeine, theobromine, and theophylline and their derivatives are used
in medicine for their bronchodilator effects.1
Uric acid is an oxidation product, via xanthine oxidase enzyme, of
xanthine and hypoxanthine. It is the final oxidation product of catabolism of
purines which originate from food. A decrease in pH, as it occurs in inflammed
tissues, facilitates the formation of uric acid crystals, which are the initial
cause of gout.