ABSTRACT

   Chitosan is a natural product derived from chitin that possesses hypocholesterolemic properties.  However, the mechanism of its cholesterol-lowering effect is still unclear.  This study was designed to investigate the effect of chitosan on plasma lipoprotein cholesterol, liver cholesterol and fecal excretion of cholesterol and bile acid in hamsters.  Hamsters were fed a high-cholesterol (0.2%) diet containing 4% cellulose (CE) or 4% chitosan (CS) for eight weeks.  The hamsters fed the CS diet had significantly lowered plasma total cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C) and low-density lipoprotein cholesterol (LDL-C) than those fed the CE diet.  CS had no effect on high-density lipoprotein cholesterol (HDL-C) level, but higher ratio of HDL-C to TC was observed in hamsters fed the CS diet when compared with those fed with the CE diet.  In addition, CS did not change plasma triglyceride and cholesteryl ester transfer protein (CETP) activity.  Hepatic cholesterol contents were significantly lower in hamsters fed CS primarily due to the reduced accumulation of the esterified cholesterol.  Fecal excretion of cholesterol and bile acid were significantly increased in hamsters after the CS treatment.  Results from this study suggest that the cholesterol-lowering effect of CS may be primarily related to an increase in fecal excretion of cholesterol and bile acid in hamsters.

Key words: chitosan, cholesterol, lipoprotein, hamsters