单丛茶多糖的表征及其体外降糖降脂活性研究

Characterization of Dancong tea polysaccharide and its in vitro hypoglycemic and lipid-lowering activity

中文关键词:  单丛茶  多糖  胆酸盐结合能力  降脂  降糖

英文关键词:Dancong tea  polysaccharide  bile acids binding ability  lipid-lowering  hypoglycemic

中文摘要:

      目的 探究单丛茶多糖的理化性质及其体外降糖降脂活性。方法 以制得的单丛茶多糖为原料, 采用苯酚-硫酸法、咔唑-硫酸法检测其糖占比情况, 采用DEAE-52色谱柱分析其多糖组成情况, 通过紫外光谱、傅里叶变换红外光谱、热重-差热分析对其进行初步表征, 通过扫描电镜观测其表面形貌, 再通过测定其对α-葡萄糖苷酶, 胰脂肪酶抑制率及体外胆酸盐结合能力, 评价其体外降糖、降脂活性。结果 该茶多糖的中性糖占比为(33.51±0.29)%, 酸性糖占比为(47.39±0.47)%, DEAE-52色谱分离在洗脱剂NaCl溶液浓度0.9 mmol/L时出现一个主要峰, 说明该茶多糖是一种酸性多糖。该多糖是以α构型的糖苷键连接的吡喃型糖环, 且其中无核酸类和蛋白类杂质。热重-差热分析表明该多糖热稳定性较好。扫描电镜观测显示其为不规则片状结构, 表面光滑且结构紧密。其与牛磺胆酸盐、甘氨胆酸盐和胆酸盐的结合率分别是(24.08±0.30)%、(8.30±0.70)%和(7.66±0.60)%, 分别相当于阳性对照考来烯胺结合率的85.71%、31.58%和25.86%。其对α-葡萄糖苷酶和胰脂肪酶的抑制作用, 最高分别达到了81.76%、61.16%, 显示出较好的抑制效果。结论 本研究获得的单丛茶多糖是一种酸性多糖, 具有较好的体外降糖、降脂活性, 在功能性食品及医疗保健领域具有良好应用前景。

英文摘要:

      Objective To explore the physical and chemical properties of Dancong tea polysaccharide and its hypoglycemic and lipid-lowering activity in vitro. Methods Using the prepared Dancong tea polysaccharide as raw material, its sugar content was detected by phenol-sulfuric acid method and carbazole-sulfuric acid method, and the composition of polysaccharide was analysed by a DEAE-52 column, and its preliminarily physical and chemical properties were characterized by ultraviolet spectra, Fourier transform infrared spectroscopy, thermo gravimetric-differential thermal analysis, and the surface morphology was observed by scanning electron microscopy. And the in vitro hypoglycemic and hypolipidemic activities of Dancong tea polysaccharides were evaluated by determining the inhibition rate of α-glucosidase, pancreatic lipase and the in vitro bile-acid binding capacity. Results The neutral sugar content of Dancong tea polysaccharide was (33.51±0.29)%, the acidic acid content was (47.39±0.47)%. DEAE-52 chromatographic separation showed a major peak when the concentration of NaCl solution was 0.9 mmol/L, indicating that the tea polysaccharide was an acidic polysaccharide. The polysaccharide was a pyranoid sugar ring connected by α-configuration glucoside bond, and there were no nucleic acid and protein impurities in it. Thermogravimetric differential thermal analysis showed that the polysaccharide had good thermal stability. Scanning electron microscopy observation results showed that it had an irregular flake structure, a smooth surface and a compact structure. Its binding rates with taurocholate, glycocholate and cholate were (24.08±0.30)%, (8.30±0.70)% and (7.66±0.60)%, respectively. Their respectively equivalent to 85.71%, 31.58% and 25.86% of the cholestyramine resin binding rate. The had inhibitory effects on both α-glucosidase and pancreatic lipase, with the highest levels reaching 81.76% and 61.16% respectively, which showing good inhibitory effects. Conclusion The Dancong tea polysaccharide obtained in this study is an acidic polysaccharide with good in vitro hypoglycemic and lipid-lowering activities, and has good application prospects in the fields of functional food and healthcare.