Alpha-cyclodextrin is a chemical compound belonging to a group of circular oligoglucosides generally called cyclodextrins. These compounds differ from each other from the number of glucosidic residues their rings are made of: the alpha form contains six residues and is the smallest cyclodextrin known. Cyclodextrins are synthetized by a bacterial enzyme of the Alpha-amylase family known as cyclodextrin glycosyltransferase (CGTase).