Neuraminidases (also known as sialidases): are enzymes that have been identified in many viruses, bacteria and eukaryotes that cleave sialic acid moieties and can be involved in many functions in vivo. It has been shown that neuramindases can play a significant role in the pathogenesis of infectious diseases, whose etiologic agents produce neuraminidase to cleave sialic acids in infected tissues to facilitate their ability to invade a host. (US2006/0241063). Neuraminidases cleave terminal sialic acid residues from cell surface molecules such as glycoproteins and glycolipids. As a result of this cleavage, internal sugar residues can be exposed that are normally protected and not available to pathogens. Neuraminidase activity can be particularly important for bacterial adhesion to mucosal surfaces. Mucous typically is highly sialyated and can be a major component of innate mucosal immunity. In mucosal diseases, commensal bacteria are separated from epithelial cells by a mucous barrier. Pathogenic bacteria have been shown to produce sialidases which can decrease the viscoity of the mucous and thus enable the bacteria to colonize on the epithelial cell membrane.

Neuraminidase Inhibitors

Neu5Ac2en is typically known as a sialidase or neuraminidase inhibitor. A preferred group of inhibitors are similar in structure to Neu5Ac2en. For example, Neu5Ac2en is known as the lead compound for the synthesis of one of the most well known sialidase inhibitors, zanamivir (Relenza) (US 2006/0241063).

An example of a neuradminidase inhibitor that has been aprroved for the treatment of human influenza isoseltamivir (Tami-flu). It is a syntehtic sialic acid analog that has been modified at the C4 position.