以鲢鱼皮为原料，采用混酶水解法制备鲢鱼皮抗氧化肽，经超滤膜分离得到SP1（>6 ku）、SP2（3~6 ku）、SP3（<3 ku）3种组分，研究不同分子质量组分的体外抗氧化能力及SP1和SP3组分的氨基酸组成，并选出体外抗氧化能力最强的SP3组分，进行体内抗氧化活性评价。结果表明：3种组分的羟自由基清除率、超氧阴离子自由基清除率和还原能力从高到低的顺序均为SP3>SP2>SP1，而铜离子螯合率无显著差异；氨基酸分析结果显示SP3组分中疏水性氨基酸所占比例较高；体内抗氧化试验显示：相较于损伤模型组，灌服SP3组分的小鼠肝脏和脾脏指数明显增大，且血清和肝脏中的超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）的酶活力明显提高，丙二醛（MDA）含量明显降低。综上可知，SP3组分在体内外均具有较好的抗氧化活性。
The polypeptides were prepared from silver carp skin by the method of mixed enzymatic hydrolysis,and divided into SP1(＞6 ku),SP2(3-6 ku) and SP3(＜3 ku) by ultrafiltration. The antioxidant capacity in vitro of three polypeptides and the amino acid composition of SP1 and SP3 were analyzed. It was suggested that SP3 has the strongest antioxidant capacity in vitro. Subsequently,the antioxidant capacity in vivo of SP3 was measured. The results showed that the order of hydroxyl radical scavenging rate,superoxide anion radical scavenging rate and reducing ability in the three polypeptides was SP3＞SP2＞SP1,but there was no significant difference in chelating rate of copper ions. Analysis of amino acid composition showed that the percentage of hydrophobic amino acid in SP3 was significantly higher than SP1. Besides, compared with the injured group,SP3 group had higher indexes of liver and spleen. Furthermore,SP3 significantly increased the activities of SOD,GSH-Px and CAT and decreased the content of MDA in serum and liver. In conclusion,SP3 has better antioxidant activity than SP1 and SP2.