Abstract:

A polysaccharide was extracted from Urechis unicinctus viscera through digestion by papain and trypsin
successively. The physico-chemical properties and structure information of the polysaccharide such as monosaccharide
composition, molecular weight and monosaccharide linkages were investigated by chemical and modern spectroscopic
analysis. The antioxidant activity in vitro of the polysaccharide was evaluated as well. The results showed that the yield
of the viscera polysaccharide (VP) from Urechis unicinctus was 6.2%. VP was a heteropolysaccharide with molecular
weight of about 4.1 × 103 u, and consisted of mannose, glucosamine, rhamnose, glucuronic acid, galactosamine, glucose,
galactose, xylose and fucose at a molar ratio of 1:1.38:0.87:0.53:0.52:5.37:1.38:1.05:2.40. VP contained 8.9% sulfate ester.
As the most dominant monosaccharide found in VP, glucose had the linkages of Glcp(1→, →4)-Glcp(1→, →4,6)-Glcp(1→
and →3,6)-Glcp(1→. And mannose had Manp(1→, →2)-Manp(1→ and →6)-Manp(1→ linkage styles. Galactose had
the linkages of Galp(1→ and →4)-Galp(1→. The linkages of fucose were composed of →4)-Fucp(1→, Fucp(1→, →3)-
Fucp(1→ and →3,4)-Fucp(1→. VP as a glycosaminoglycan-like polysaccharide had rich bioactivities. VP possessed good
lipid peroxidation inhibition ability as evidenced by its EC50 value at 2.47 mg/mL. At 10 mg/mL, the inhibition rate of lipid
peroxidation by VP was near 90%.

Key words: Urechis unicinctus, viscera polysaccharide, structure, physico-chemical property, lipid peroxidation