Xanthine is a purine base that occurs naturally in the body and is involved in the metabolism of nucleic acids. 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 found in various foods and beverages, particularly in coffee and tea. It is also a precursor to several important compounds, including caffeine and theophylline, which have stimulant and therapeutic effects.