Glycoside

**Semantic type:** Biologically Active Substance

**Definition:** Any compound in which a sugar group is covalently bonded through its anomeric carbon to another group via an O-glycosidic bond or an S-glycosidic bond; glycosides involving the latter are also called thioglycosides. However, substances containing N-glycosidic bonds, where the anomeric carbon is bound to some other group via a nitrogen atom, are called glycosylamines; the term "N-glycoside" is considered a misnomer by IUPAC and is discouraged. Furthermore, the sugar group needs to be bonded to a non-sugar for the molecule to qualify as a glycoside, thus excluding the polysaccharides. The sugar group in glycosides is known as the glycone, which can be a single sugar group (monosaccharide) or several sugar groups (oligosaccharide); the non-sugar group is known as the aglycone or genin.