paraxanthine (84%),<unk>  (12%), and theophylline (4%alt=A diagram featuring 4 skeletal chemical formulas. Top (caffeine) relates to similar compounds paraxanthine,<unk>  and theophylline. Even without dietary intake,<unk>  may occur in the body as it is a product of the human metabolism of caffeine, which is metabolised in the liver into 12%<unk> , 4% theophylline, and 84% paraxanthine. In the liver,<unk>  is metabolized into xanthine and subsequently into methyluric acid. Important enzymes include CYP1A2 and CYP2E1. "The main mechanism of action for methylxanthines has long been established as an inhibition of adenosine receptors". Its effect as a phosphodiesterase inhibitor is thought to be small.
Theobromine
Phosphene
Benzoctamine
Cromoglicic acid
Chlorotrianisene
Magnetophosphene
Adapromine
Lepromin