Sialic acid is a derivative of a 9-carbon monosaccharide. The name comes from the Greek (ÏÎ¹Î±Î»Î¿Ï (sialos) âsalivaâ) which is a negatively charged ion that produces a smooth feel in saliva. Not only does it have the effect of "inducing" invading germs, it is also currently recognized as a ganglioside transmitter and is part of the brain.