单环刺螠内脏多糖结构的分析及其对脂质过氧化物的清除作用

为开发单环刺螠内脏中活性多糖成分，利用两步酶解法提取单环刺螠多糖，对其单糖组成、分子质量和连接方式等理化性质和结构特征进行研究，并通过体外清除脂质过氧化物实验对其活性进行初步评价。结果表明：采用木瓜蛋白酶和胰蛋白酶两步酶解后，单环刺螠内脏多糖得率为6.2%。单环刺螠内脏多糖（viscera polysaccharide，VP）分子质量约为4.1×103 u，从单糖组成可以看出，VP为组成复杂的类糖胺聚糖，主要含有葡萄糖（Glc），其次还含有氨基葡萄糖（GlcN）、甘露糖（Man）、半乳糖（Gal）和岩藻糖（Fuc），还含有少量的木糖（Xyl）、鼠李糖（Rha）、葡萄糖醛酸（GlcUA）和氨基半乳糖（GalN）。其单糖组成物质的量比为n（Man）∶n（GlcN）∶n（Rha）∶n（GlcUA）∶n（GalN）∶n（Glc）∶n（Gal）∶n（Xyl）∶n（Fuc）＝1∶1.38∶0.87∶0.53∶0.52∶5.37∶1.38∶1.05∶2.40。VP还含有少量的硫酸基，含量为8.9%。葡萄糖作为VP中最主要的单糖，其连接方式主要为Glcp(1→、→4)-Glcp(1→、→4,6)-Glcp(1→和→3,6)-Glcp(1→。甘露糖主要含有Manp(1→、→2)-Manp(1→和→6)-Manp(1→连接方式。半乳糖含有Galp(1→和→4)-Galp(1→连接方式。而岩藻糖主要含有→4)-Fucp(1→，另外还有Fucp(1→、→3)-Fucp(1→和→3,4)-Fucp(1→连接方式。类糖胺聚糖具有丰富的生物活性，对VP进行初步体外抗氧化活性研究表明，其具有显著的脂质过氧化物清除活性，半数清除质量浓度为2.47 mg/mL。

Physico-chemical Properties and Structure Analysis of Viscera Polysaccharide of Urechis unicinctus and Its Lipid Peroxidation Inhibition Activity

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%.