rutinose

Rutinose is a disaccharide component found in several plant glycosides, most notably in rutin, the flavonol quercetin-3-O-rutinoside. It consists of two monosaccharide units, α-L-rhamnopyranose and β-D-glucopyranose, linked through a 1→6 glycosidic bond (α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranose).

In rutin, the disaccharide is attached to the aglycone (quercetin) through the anomeric carbon of the glucose residue, forming quercetin-3-O-rutinoside. Within the rutinoside itself, the rhamnose unit is connected to the glucose unit at the glucose C6 position, i.e., rhamnose C1–glucose C6. This arrangement means the sugar moiety is an integral part of the glycoside and contributes to its overall properties.

Occurrence and significance: Rutinosides are widespread in the plant kingdom and occur in a variety of glycosides beyond rutin. They can influence the solubility, stability, and bioavailability of their aglycones, and are frequently involved in the storage and transport of flavonoids and other secondary metabolites. The presence of rutinoside can affect how these compounds are metabolized in plants and, after ingestion, by humans and other animals.

Biosynthesis and hydrolysis: In plants, rutinoside formation is accomplished by glycosyltransferases that attach rhamnose from UDP-rhamnose to a glucose unit linked to the aglycone. Hydrolysis of rutinosides, whether by acid or specific enzymes such as rutinosidases and rhamnosidases, cleaves the glycosidic bonds to yield the aglycone and the constituent monosaccharides, rhamnose and glucose.