Guanosine is a purine nucleoside composed of guanine attached to a ribose sugar via a β-N9-glycosidic bond. It serves as a fundamental building block of RNA and is involved in various cellular processes including energy transfer (as GTP), signal transduction, and protein synthesis. In food chemistry, guanosine and its derivatives contribute to nucleotide pools in meats, seafood, and fermented products, indirectly influencing flavor precursors. It exhibits low solubility in cold water but increases with temperature or pH adjustment. Chemically stable under physiological conditions, it participates in enzymatic reactions catalyzed by nucleoside phosphorylases and kinases. Research indicates roles in neuroprotection and potential therapeutic applications in antiviral and anticancer contexts through modified analogs.