There are many types of naturally occurring compounds in which a sugar molecule and a non-carbohydrate molecule are bound. A common substance usually found in plants and less commonly found in animals, these compounds — called glycosides — perform important roles in the life of the organisms that house them. There are so many types of glycosides that they must be subdivided into more specific classifications. The term "glucoside" usually refers to a specific configuration of a glycoside in which glucose is the sugar bound to another non-carbohydrate molecule.
Plants might contain many glucoside molecules and these compounds usually perform important functions in the life of the plant. For instance, important glucoside molecules for human use are derived from certain types of wood, mustard seeds, black pepper, and many other plants. Usually the aromatic compounds in plants, glucoside molecules might store some chemical vital to the plant's every day processes and which can be refined by hydrolysis or other means to create specific derivative chemicals.
Though the term originally applied only to the naturally occurring compounds in plants, a glucoside molecule can also refer to a synthetic ether derivative produced by chemical processes, fermentation or decomposition by some means. When put through treatments either with dilute acid or specific types of enzymes, natural glucosides usually yield glucose molecules and other substances. These synthetic ethers have a wide range of applications, including as surfactants and medical substances. To get these useful chemicals, a wide range of processes can be used.
The type of non-carbohydrate created usually depends on the means of treatment of the original glucoside. Using specific enzymes or dilute acids on the same plant material might produce different types of glucoside molecules. Fermenting the same rhubarb plant with different enzymes, for instance, would probably have a different end result. There is such a wide range of glycosides derived through a variety of methods that classifying all of them is a bit of a challenge.
The complex nature of glycosides, in general, means defining each glucoside is usually a complex process. A few different classification schemes exist, including classification based on the sugar, non-carbohydrate, or other chemical feature unique to a particular molecule. When classified by the non-carbohydrate molecule only, four major categories are usually used: ethylene, benzene, styrolene, and antracene derivatives. Other classification schemes might group glucosides by plant genera, because most of the base compounds come from plants.