Inosine (I)

Inosine is a naturally occurring purine nucleoside consisting of hypoxanthine linked to a ribose sugar, serving as a central intermediate in purine metabolism [1.2.1, 1.3.3]. It is primarily generated through the deamination of adenosine by adenosine deaminase (ADA) or the dephosphorylation of inosine monophosphate (IMP) [1.2.1, 1.3.2]. Biologically, inosine acts as a signaling molecule and a functional agonist for adenosine receptors, particularly the A1, A2A, and A3 subtypes, through which it exerts significant anti-inflammatory, immunomodulatory, and neuroprotective effects [1.1.2, 1.2.4]. In the context of disease, inosine has been investigated as a therapeutic agent for neurodegenerative conditions like Parkinson's disease and Multiple Sclerosis, largely due to its ability to increase levels of uric acid, a potent endogenous antioxidant [1.3.3, 1.3.4]. Furthermore, it plays a critical role in RNA biology as a modified base in tRNA (wobble position) and is involved in adenosine-to-inosine (A-to-I) RNA editing [1.2.1, 1.2.2]. While generally considered safe, therapeutic use of inosine is limited by the risk of hyperuricemia and the subsequent development of gout or kidney stones [1.4.1, 1.4.3].

Other names

Hypoxanthine riboside9-beta-D-ribofuranosylhypoxanthineInoHypoxanthosine1,9-dihydro-9-beta-D-ribofuranosyl-6H-purin-6-one

Inosine functions as an agonist for adenosine receptors (A1, A2A, A3), modulates the immune response by suppressing pro-inflammatory cytokines, and serves as a precursor to the antioxidant uric acid [1.1.2, 1.3.4, 1.4.1].