Xanthine Products | Cleanchem - Xanthine is a purine base that occurs naturally in the body and is involved in various biological processes, including the metabolism of nucleotides. It is the precursor to important molecules like uric acid, caffeine, and theophylline. Xanthine derivatives, such as theophylline, are commonly used as bronchodilators in the treatment of asthma and chronic obstructive pulmonary disease (COPD). These drugs help relax the muscles around the airways, making it easier to breathe.