茯砖茶褐素组分特征及对α-葡萄糖苷酶活性抑制研究

摘要

By using Fuzhuan brick tea as raw material, five kinds of theabrownin with different molecular weight (≤3.5 kDa、3.5-25 kDa、25-50 kDa、50-100 kDa and ≥100 kDa) have been obtained by membrane separation technology. The spectral and physicochemical properties and inhibition on the α-glucosidase activity of theabrownins were comparative studied. The results showed 39 components from pyrolysis of Fuzhuan theabrownines were identified. The results showed that the theabrownins possessed the advantageous hypoglycemic effect. Effects of biological activity influenced by the total content of acidic group, carboxyl, phenolic hydroxyl, polysaccharide and protein. Five kinds of theabrownin belong to phenolic compounds containing hydroxyl, alkyl, carboxyl and phenyl, and showed a characteristic absorption peak at the 230 nm in UV-vis spectrum. The polysaccharide contents increased with the increase of theabrownin molecular weight, while the protein decreased. The theabrownin with molecular weight 25-50 kDa showed highest inhibition rate to α-glucosidase, which is equivalent of 1.9 times to that of acarbose. It is suggested that the Fuzhuan brick theabrownine is a benzene substance containing polyphenols, polysaccharides and proteins, which constitute a half chair or the chair conformation.%采用膜分离技术得到分子质量分别为≤3.5 kDa、3.5~25 kDa、25~50 kDa、50~100 kDa 和≥100 kDa 的5种茯砖茶褐素，比较了其光谱和理化性质，鉴定出可能存在的39种成分，研究了它们对α-葡萄糖苷酶活性抑制作用的差异。结果显示，茯砖茶褐素具有优越的降糖功效，活性强弱与总酸性基团、羧基、酚羟基、多糖、蛋白质等含量有关。5种茶褐素属酚类物质，均含有羟基、烷基、羧基及苯环，且在230 nm 处有一特征吸收峰。多糖含量随着分子量的增加而增加，蛋白质含量反之，活性显示25~50 kDa 透出部分对α-葡萄糖苷酶的抑制率最高，相当于阿卡波糖的1.9倍。推测茯砖茶褐素属苯多酚类，内含多糖、蛋白质等物质，共同构成半椅状或椅状构型。