Abstract: The antioxidant capacity of polysaccharides extracted from abalone viscera was studied by measuring their 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging capacity and their ability to protect human liver LO2 cells against H2O2-induced oxidative damage. The results demonstrated that the crude polysaccharide (CAVP) and two purified fractions (AVP1 and AVP2) all had apparent free radical scavenging capacity with a half maximal inhibitory concentrations (IC50) of DPPH radical scavenging activity of 1.46, 1.74 and 1.55 mg/mL, respectively, and an IC50 of hydroxyl radical scavenging activity of 7.14, 15.27 and 8.11 mg/mL, respectively. In addition, all three polysaccharides in the concentration range from 0.5 to 4.0 mg/mL could protect LO2 cells against H2O2-induced oxidative damaged as indicated by significantly increased survival rate and CAVP at 4.0 mg/mL, AVP1 at 0.5 mg/mL and AVP2 at 0.5 mg/mL decreased the activity of lactic dehydrogenase (LDH) in cell culture supernatant. CAVP significantly increased the intracellular activities of glutathione peroxidase (GSH-Px) at 4.0 mg/mL, catalase (CAT) at 0.5 mg/mL and superoxide dismutase (SOD) at 0.5 mg/mL. AVP1 at 4.0 mg/mL resulted in a significant elevation in CAT activity and a highly significant increase in GSH-Px and SOD activities. AVP2 at both 0.5 and 4.0 mg/mL could highly significantly increase CAT activity. All three polysaccharides at 4.0 mg/mL could significantly reduce the content of malondialdehyde (MDA) as a lipid peroxidation product. Therefore, abalone visceral polysaccharides could be used as potential antioxidant ingredients in functional foods.

Key words: abalone viscera, polysaccharide, antioxidant activity, LO2 cells