【作者】 周丽霞； 张雨青； 马永雷； 卢立真； 贺天珍； 李琳； 周珍祯； 阎海波；

【Author】 Li-Xia Zhou,Yu-Qing Zhang,Yong-Lei Ma,Li-Zhen Lu,Lin Li,Tian-Zhen He,Zhen-Zhen Zhou and Hai-Bo Yan The State Engineering Laboratory of Modern Silk,Soochow University,Suzhou 215123,People’s Republic of China;Silk Biotechnology Key Laboratory of Suzhou City,Medical College of Soochow University,Suzhou 215123,People’s Republic of China

【机构】 苏州大学基础医学与生物科学学院蚕丝生物技术实验室；

【摘要】 家蚕丝是由丝素纤维(约70%)和其周围的丝胶层(约30%)组成,后者中丝胶蛋白占到25%,非丝胶蛋白成分占5%左右。这些非丝胶组分包括碳水化合物、盐和蜡质等成分,而关于它们的抗氧化性以及抑制酪氨酸酶等活性很少有人做过研究。但是,关于茧层中丝胶蛋白及其水解物的活性已经有了详尽的报道。在本文中,我们通过120°C高温水2h脱胶处理,然后用50%乙醇萃取分离,从五种茧壳丝胶层中制备出了5种乙醇提取物。这些醇提物主要是由黄酮类化合物、丝胶寡聚肽或者游离氨基酸等成分组成。本试验对这些醇提物及其丝胶蛋白样品的生物学活性进行了体外详细研究。结果表明,与纯化丝胶蛋白相比,其醇提物对自由基的清除和酪氨酸酶的抑制能力要强得多。另外,醇提物对α-葡萄糖苷酶的抑制能力也很强,而丝胶蛋白却几乎没有这种活性。在所有的样品中,大造茧中醇提物的各种抑制能力都是最强的,它对DPPH自由基的清除、酪氨酸酶和α-糖苷酶抑制作用的IC50值分别为170μg/mL,27μg/mL和110μg/mL。氨基酸组成分析和总黄酮测定结果表明,这些醇提物的生物学活性与其总黄酮含量呈正相关而与其总氨基酸含量并无直接关系,蚕茧丝胶层醇提物比其丝胶蛋白的生物学活性要强得多。因此,家蚕茧丝胶层的醇提物可以或与丝胶蛋白一起应用于医药领域或糖尿病患者的保健食品。更多还原

【Abstract】 Silk from silkworm Bombyx mori consists of silk fibroin fiber (about 70%) and sericin layer (30%) around the fiber,in which sericin protein accounts for about 25% and non-sericin component about 5%.The bioactivities of antioxidation and anti-tyrosinase of the non-sericin component involving carbohydrate,salt and wax have hardly been investigated,but the sericin and its hydrolyzate in cocoon sericin layer has been described in detail.In the present paper,we prepared five kinds of sericin proteins and ethanol extracts from the sericin layer of silkworm cocoons by means of degumming treatment in 120°C water for 2 h and subsequently extraction and separation in 50% ethanol.The resulting ethanol extracts are composed mainly of non-sericin components such as flavonoids and sericin oligopeptides or free amino acids.Here,the bioactivities of the five ethanol extracts and the purified sericin samples were determined in vitro in detail.The results showed that all these ethanolic extracts from the silkworm cocoons had much stronger inhibitory activities of DPPH free radical and tyrosinase in comparison with their purified sericin proteins.In addition,the former had strong inhibitory activity of α-glucosidase while the latter had no such activity.In particular,the inhibiting ability of the ethanolic extract in Daizo Bombyx cocoon was the strongest of all cocoon shells and its IC50 values for the inhibition of DPPH free radical,tyrosinase and α-glucosidase were 170 μg/mL,27 μg/mL and 110 μg/mL,respectively.The analysis of amino acid composition and total flavonoids revealed that these bioactivities of ethanol extracts were related positively to the level of total flavonoids but not related to that of total amino acids in the ethanolic extract from silkworm cocoon.Thus,the bioactivities of the non-sericin component are far better than sericin alone in cocoon sericin layer.The ethanol extract in the sericin layer of silkworm cocoon as a novel functional stock could be extensively applied together with sericin protein to medical biomaterials/drugs or health food for diabetic patients.更多还原