Polyhydroxypyrrolizidines, 1., , and as well as indolizidines and imminosugars are potential inhibitors of glycosidases, a class of enzymes which hydrolyse glycosidic bonds in oligo- and polysaccharide chains. Glycosidases are involved in the biosynthesis of glycoproteins, which are responsible for cell to cell and cell to exogen molecular recognition processes. Inhibitors of these enzymes can therefore be active as antibacterial, antitumoral and antiviral agents. The great ...