Radical scavenging activity of chitooligosaccharide with different molecular weights

Two chitooligosaccharides, Ch1100 (average molecule weight: 1,100; average degree of polymer: 7) and Ch500 (average molecule weight: 500; average degree of polymer: 3), were obtained by partial hydrolysis of chitosan. Their antioxidant activities were investigated with scavenging activity of chitooligosaccharide against superoxide radical using phenazin methosulphate (PMS)-beta-nicotinamide adenine dinucleotide (NADH)-nitroblue tetrazolium (NBT) system, scavenging activity of chitooligosaccharide against carcinogen-induced active oxygen species and scavenging activity of chitooligosaccharide against hydrogen peroxide released from polymorphonuclear leukocytes stimulated by phorbol-12-myristate-13-acetate (PMA). By the aforementioned three measurements, the radical scavenging activity (Inhibition%) of Ch1100 was determined to 54.8, 35.3 and 38.9%, respectively, at the concentration of 100 mu mol/L, while that of Ch500 was 40.1, 13.9 and 18.2%, respectively, at the same concentration. These results clearly suggest that Ch1100 is a potent radical scavenger, which has the high radical scavenging activity.