Uridine is a naturally occurring pyrimidine nucleoside that forms a basic building block of RNA and plays an important role in carbohydrate metabolism and cellular energy processes. It was first isolated in the early 20th century from yeast RNA hydrolysates, contributing to the understanding of nucleic acid composition and structure. Over time, uridine gained interest in biochemistry and medicine for its potential roles in brain function, lipid metabolism, and as a supplement in certain neurological and metabolic conditions.