Guanosine is a purine nucleoside, in which the guanine attached to the C1 carbon of a ribose (ribofuranose) ring via a β-N9-glycosidic bond. Its phosphorylated derivatives include GMP (guanosine monophosphate), cGMP (cyclic guanosine monophosphate), GDP (guanosine diphosphate), and GTP (guanosine triphosphate). These guanosine derivatives are very important in various biochemical processes, such as synthesis of nucleic acids and proteins, photosynthesis, muscle contraction, and intracellular signal transduction.
Guanosine is thought to have neuroprotective properties. It can reduce neuroinflammation, oxidative stress, and excitotoxicity, as well as exerting trophic effects in neuronal and glial cells. It is shown to be protective in central nervous system diseases including ischemic stroke, Alzheimer’s disease, Parkinson’s disease, spinal cord injury, nociception, and depression. Guanosine is found to be associated with purine nucleoside phosphorylase (PNP) deficiency, which is an inborn error of metabolism.