Subacute Oral Toxicity of Chitosan Oligosaccharides on Sprague Dawley Rats

Chitosan is derived from chitin by deacetylation in the presence of alkali, which is a copolymer consisting of $\beta$-(1longrightarrow4)-2-acetamido-D-glucose and $\beta$-(1longrightarrow4)-2-amino-D-glucose units with the latter usually exceeding 80% (Arvanitoyannis et al., 1998). Chitosan has been developed as new physiological material since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, even though chitosan has very strong functional properties in many areas, its high molecular weight and high viscosity may restrict the use in vivo. In addition, there is little doubt that such properties will influence absorption in the human intestine. Recently, studies on chitosan have attracted interest for converted chitosan to oligosaccharide, because the oligosaccharide possesses not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice, antifungal activity, calcium absorption accelerating effect (Jeon et al., 1999) and antimicrobial activity. There is, however, little information on the toxicity of chitosan oligosaccharide. (omitted)