caffeine

1-Methylxanthine is a caffeine derivative. 1-Methylxanthine is an essential human urinary metabolite of caffeine and theophylline (1,3-dimethylxanthine, TP). 1-Methylxanthine enhances the radiosensitivity of tumor cells.

Salicylamide (2-Hydroxybenzamide) is an over-the-counter drug with analgesic and antipyretic properties, which has similar medicinal properties to aspirin. In the over-the-counter pain remedies, Salicylamide is used in combination with both aspirin and caffeine.

(R)-(+)-Citronellal ((+)-Citronellal) is a monoterpene compound isolated from citrus, lavender, and eucalyptus oils. It has antifungal activity and reduces the bitterness of caffeine by inhibiting bitter receptors TAS2R43 and TAS2R46. It is commonly used in skincare products.

1,3,7-Trimethyluric acid, a purine alkaloid, occurs as a minor metabolite of caffeine in humans. It functions as an antioxidant with the ability to scavenge hydroxyl radicals and offers protective benefits against lipid peroxidation in erythrocyte membranes.

Paraxanthine (1,7-dimethylxanthine) is a metabolite of caffeine (sc-202514) which functions as an adenosine receptor ligand and a PARP-1 inhibitor in pulmonary epithelial cells. Studies suggest that Paraxanthine is structurally similar to caffeine and possibly mediates the physiological effects of caffeine. Also Paraxanthine acts as a competitive phosphodiesterase inhibitor, which increases intracellular cAMP, activates PKA, inhibits TNF-α and leukotriene synthesis. In addition, Paraxanthine acts as a Na+ K+ ATPase enzymatic effector.

Methylliberine, an orally active purine alkaloid metabolite of caffeine, exhibits similar properties to its precursor.