Xanthine is a purine base that occurs naturally in the body and is involved in the metabolism of nucleotides. It is produced from the breakdown of adenine and guanine, two important components of DNA and RNA. Xanthine can be further metabolized into uric acid, which is excreted in urine. In addition to its role in metabolism, xanthine is also found in certain foods and beverages, such as tea and coffee. It is a precursor to other compounds, including caffeine, which is a stimulant. Xanthine derivatives are sometimes used in medicine to treat respiratory conditions due to their ability to relax bronchial muscles.