5Oglucoside

5-O-glucoside is a class of glucoside in which a glucose unit is attached to another molecule through an oxygen atom located on the molecule’s 5-hydroxyl group, forming an O-glycosidic bond. In most cases the linkage involves the glucose anomeric carbon (C1) to the aglycone’s 5-OH, resulting in a beta-D-glucoside-type bond, though the exact configuration can vary with the biosynthetic enzyme.

Formation and breakdown: 5-O-glucosides are typically produced by UDP-glucose–dependent glycosyltransferases in plants or microbes, using UDP-glucose as the glucose donor. They can also form under certain nonenzymatic conditions. These compounds are commonly hydrolyzed by beta-glucosidases to release the aglycone and glucose, a reaction that can regulate the activity, solubility, and storage form of the aglycone.

Occurrence and roles: They are found across a variety of natural products, including phenolics and other plant secondary metabolites. Glycosylation at the 5-position can alter properties such as solubility, stability, and bioavailability, and can influence interactions with biological targets and transport mechanisms. In many cases, 5-O-glucosides serve as storage or transport forms that release the active aglycone upon hydrolysis.

Analysis: Analytical detection commonly relies on the mass increase corresponding to the glucose moiety (about 162 Da) and fragmentation patterns observed by LC-MS or HPLC methods. Nomenclature emphasizes the attachment point on the aglycone, rather than naming a single compound.

Note: The term 5-O-glucoside is descriptive and can refer to any compound with glucose bound at the aglycone’s 5-position; specific examples are named individually.