Biochemical activities of low molecular weight chitosans derived from squid pens

Chitosans were prepared by H2O2 oxidative depolymerization from squid pens with low molecular weights (LMW) of 13,025, 7011, 4169, 2242 and 963 Da. The bile acid binding capacities and antioxidant properties of LMW chitosans were studied in vitro. LMW chitosans exhibited stronger bile acid binding capacities than that of chitosan. The scavenging ability of LMW chitosans against DPPH radicals improved with increasing concentration, and EC50 values were below 1.3 mg/mL. The EC50 values of LMW chitosans against hydroxyl radicals ranged from 0.93 to 3.66 mg/mL. All LMW chitosans exhibited a strong ferrous ion chelating effect and reducing power. At 1 mg/mL, the scavenging ability of chitosan-963 towards superoxide radicals was 67.76%. These results indicated that LMW chitosans which have stronger bile acid binding capacity and antioxidant activities may act as potential antioxidants in vitro.