Antioxidant properties of high molecular weight dietary chitosan in vitro and in vivo

The effect of high molecular weight chitosan supplement (HMCS), a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. The use of HMCS for 8 weeks resulted in a significant decrease in total cholesterol levels and atherogenic index, and increased levels of high density lipoprotein (HDL) cholesterol. HMCS treatment also resulted in a lowered ratio of oxidized to reduced albumin and an increase in total plasma antioxidant activity. A good correlation between the atherogenic index and oxidized albumin ratio was found. The results suggest that the ratio of oxidized to reduced albumin ratio represents a potentially useful marker of the metabolic syndrome. In in vitro studies, HMCS slightly reduced the levels of two stable radicals in a dose- and time-dependent manner. The strong binding capacity of indoxyl sulfate and low density lipoprotein (LDL) cholesterol was also observed with HMCS. These results suggest that HMCS reduces significant levels of pro-oxidants such as cholesterol and uremic toxins in the gastrointestinal tract, thereby inhibiting the subsequent development of oxidative stress in the systemic circulation in humans.