Chitosan hypocholesterolemic activity

Sugano, M., Yoshida, K., Hashimoto, H., Enomoto, K., and Hirano, S. (1992). Hypocholesterolemic activity of partially hydrolyzed chitosan in rats. In "Advances in Chitin and Chitosan", (C. J. Brine, P. A. Sanford, and J. P. Zikakis, Eds), pp. 472-478. Elsevier Applied Science, London and New York. 

Chitosan has been reported to cause significant hypocholesterolemic activity in different experimental animals (Hirano et al., 1990 Sugano et al., 1978, 1980 Ylitalo et al., 2002). Sugano et al. (1988) noted that chitosan oligomers did not exhibit this effect. The studies were carried out on rat groups fed on a diet rich in cholesterol to find the effect of chitosan hydrolysates with different MWs and viscosity on the hypocholesterolemic activity. The lower the MW of chitosan, the better its cholesterol-lowering potential. 

Chitosan and its derivative exhibited the great antihyperglycemic, antihyperlipidemic, and anti-hypocholesterolemic activities in type 1 and type 2 diabetic animal models. Moreover, chitin, chitosan, and their derivatives exhibited cholesterol-lowering activity in animal and clinical studies. Therefore, chitin, chitosan, and their derivatives can be promising candidates as potential material for protecting diabetes mellitus and lowering the cholesterol absorption. 

Chitosan has been purported to possess both hypolipidemic and hypocholesterolemic activity. Many studies have been conducted to scientifically prove its efficacy and experiments conducted on animal models have demonstrated that it lowers the blood and liver triglyceride and total cholesterol levels [32,33]. Extrapolating results from these animal studies to humans was tried, but the hypolipidemic action of chitosan in human beings was observed only upon long-term and high-dose supplementation [34,35]. 

Chitosan is known to have a significant hypocholesterolemic activity in various experimental animals. Chitosan has been tested for reducing cholesterol, it has lipid-lowering effects similar to those of cholestyramine and has been used in clinical application. 

In vivo studies also showed that chitosan has hypocholesterolemic and hypolipidemic activities (Nagyvary et al., 1979 Sugano et al., 1978,1980). 

Possible Mechanism of Hypocholesterolemic and Hypolipidemic Activity of Chitosan... 

The available data indicate that the hypocholesterolemic and hypolipidemic activity of chitosan is probably due to disruption and/or inhibition of micelle formation. At pH 6.0-6.5 chitosan begins to precipitate and as the linear chains of the polysaccharide start to aggregate, they can entrap the whole micelles. The entrapped cholesterol, fatty acids and monoglycerides thus escape absorption. Such "polar entrapment," shown in Figure 2, can occur in the duodenum. Another mode of action could be the "disintegration" of mixed micelles, which can start before the precipitation of chitosan, and in which the free fatty acids and bile acids are selec-... 

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