Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a monosaccharide with a nine-carbon backbone.

It is also the name for the most common member of this group, N-acetylneuraminic acid (Neu5Ac or NANA). Sialic acids are found widely distributed in animal tissues and to a lesser extent in other organisms, ranging from fungi to yeasts and bacteria, mostly in glycoproteins and gangliosides (they occur at the end of sugar chains connected to the surfaces of cells and soluble proteins).

1. Sialic acid: Sialic acid is a derivative of a 9-carbon monosaccharide. The name comes from the Greek σιαλοσ (sialos) 'saliva'.

2. This is a negatively charged ion that gives the saliva a smooth feel.

3. It is not only based on the role of "inducing" invading pathogens, but is currently recognized as a transmitter of gangliosides and is a component of the brain.

4. Sialic acid can prevent the invasion of germs.

5. Sialic acid is also a receptor for influenza viruses, and is a binding site for influenza viruses to bind to mucous cells.