Caffeine functional groups refer to the chemical structures within the caffeine molecule that determine its properties and biological effects. The purine ring, trimethylxanthine, and methylxanthine are key functional groups that contribute to caffeine’s stimulating, diuretic, and vasodilatory effects. These groups influence its interactions with cellular receptors, allowing caffeine to exert its physiological responses on the central nervous system, cardiovascular system, and other bodily functions. Understanding these functional groups is crucial for comprehending the mechanism of action and potential health implications associated with caffeine consumption.