食品科学 ›› 2018, Vol. 39 ›› Issue (19): 162-168.doi: 10.7506/spkx1002-6630-201819025

• 营养卫生 • 上一篇    下一篇

茶多糖的结构特征与降血糖活性

宋林珍1,朱丽云2,*,高永生1,3,李素芳1,张拥军1   

  1. 1.中国计量大学 海洋食品加工质量控制技术与仪器国家地方联合工程实验室,浙江 杭州 310018; 2.中国计量大学现代科技学院,浙江 杭州 310018;3.安徽汉芳生物科技有限公司,安徽 淮北 235000
  • 出版日期:2018-10-15 发布日期:2018-10-24
  • 基金资助:
    国家自然科学基金面上项目(31371765);浙江省重点科技创新团队项目(2010R50028)

Structural Characteristics and Hypoglycemic Activity of Polysaccharides from Green Tea Leaves

SONG Linzhen1, ZHU Liyun2,*, GAO Yongsheng1,3, LI Sufang1, ZHANG Yongjun1   

  1. 1. National & Local United Engineering Laboratory of Quality Controlling Technology and Instrumentation for Marine Food, China Jiliang University, Hangzhou 310018, China; 2. College of Modern Science and Technology, China Jiliang University, Hangzhou 310018, China; 3. Anhui Hanfang Bio-technology Co. Ltd., Huaibei 235000, China
  • Online:2018-10-15 Published:2018-10-24

摘要: 探讨茶多糖的结构特征与抗糖尿病机制,为多糖的应用与糖尿病天然药物的开发提供理论依据。从粗老茶叶中分离茶多糖并纯化,分析了其单糖组成、分子质量、紫外与红外吸收特征。以四氧嘧啶诱导小鼠非肥胖型糖尿病,茶多糖以100 mg/(kg·d)剂量灌胃治疗糖尿病小鼠42 d,以格列本脲为阳性药物对照,测定血清和肝脏中的空腹血糖浓度、血清胰岛素含量和总抗氧化状态,苏木精-伊红染色法观察胰岛、肝脏组织变化。结果表明,从粗老茶叶中分离的茶多糖分子质量为119 600 Da,由D-葡萄糖醛酸、鼠李糖、D-岩藻糖、L-阿拉伯糖、D-木糖、D-甘露糖、D-葡萄糖和D-半乳糖8 种单糖组成,其物质的量比为32.61∶1.00∶5.46∶8.13∶3.84∶2.37∶15.36∶7.52,紫外与红外光谱扫描结果推测其可能为一种不含蛋白、核酸的吡喃型酸性杂多糖。茶多糖药物组小鼠肝糖原含量显著升高,血糖浓度从18.98 mmol/L降至正常水平,其血浆和胰脏中胰岛素含量与正常组无显著差异(P>0.05),血清与肝脏中超氧化物歧化酶活力显著高于四氧嘧啶模型组(P<0.05),而肝脏中一氧化氮合酶活力和丙二醛含量接近阴性组水平,一氧化氮含量显著低于模型组(P<0.05),其作用效果与格列本脲相近。病理组织形态学结果显示,茶多糖药物组小鼠胰岛β细胞得到修复,肝脏组织病理形态恢复正常。本研究表明茶多糖通过改善胰岛素分泌、胰岛β细胞功能和抗氧化状态发挥抗糖尿病作用。

关键词: 茶多糖, 结构特征, 抗氧化活性, 降血糖活性, 胰岛素分泌, 胰岛β细胞功能

Abstract: The aim of this study was to evaluate the structural characteristics and anti-diabetic mechanism of tea polysaccharides, dietary ingredients used for the management of diabetes. A water-soluble polysaccharide was isolated and purified from mature tea leaves, and its monosaccharide composition and molecular mass were measured. Also, its structural characteristics were analyzed by ultraviolet (UV) and infrared (IR) spectroscopy were. Alloxan was injected into ICR mice to induce non-obese type diabetes. The diabetic rats were treated with the polysaccharide (100 mg/(kg·d)) or glibenclamide (positive control) for 42 days. The fasting blood glucose, serum insulin and total antioxidant parameters in serum and liver were determined. The pancreas was examined by haematoxylineosin staining and β-cells were observed using a microscope. The results showed that the molecular mass of the polysaccharide was 119 600 Da, which was composed of glucuronic acid, rhamnose, fucose, arabinose, xylose, mannose, glucose and galactose with a molar ratio of 32.61:1.00:5.46:8.13:3.84:2.37:15.36:7.52. Based on the UV and IR spectra, it seemed likely that the polysaccharide was a non-protein-bound pyran-type heteropolysaccharide. The treatment of the diabetic rats with the polysaccharide significantly elevated liver glycogen content, and decreased blood glucose to normal from 18.98 mmol/L, but exhibited no significant difference in pancreatic and plasma insulin levels compared with the normal group (P > 0.05). Moreover, treatment with the polysaccharide significantly increased superoxide dismutase activity compared with the model group (P < 0.05), but showed nitricoxide synthase activity and malonaldehyde content in liver close to those of the negative group; however, a significant decrease in nitric oxide in liver was found in comparison with the model group (P < 0.05). The effect of the polysaccharide was similar to that of glibenclamide. Histopathological and morphological results demonstrated that pancreatic β-cells and liver tissue morphology in the polysaccharide treated group were restored to normal. Thus, this study suggests that the tea polysaccharide exerts anti-diabetic effects by improving insulin secretion, β-cell function, and antioxidant status.

Key words: tea polysaccharides, structural characteristics, antioxidant activity, hypoglycemic activity, insulin secretion, β-cell function

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