Hong Tao, Zhao Jiaying, Yin Junyi, Nie Shaoping, Xie Mingyong
State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology, Key Laboratory of Bioactive Polysaccharides of Jiangxi Province, Nanchang University, Nanchang, China.
Front Nutr. 2022 Apr 13;9:878249. doi: 10.3389/fnut.2022.878249. eCollection 2022.
Tea is a popular beverage with a long history of safe and healthy use. Tea polysaccharide is a bioactive component extracted from tea, which has attracted more and more attention in recent decades. In this article, an acidic polysaccharide Gougunao tea polysaccharide (GPS) was isolated from Gougunao green tea by hot water extraction and ethanol precipitation. After purification by a diethylaminoethyl (DEAE) Sepharose Fast Flow column and a Sephacryl S-400 column, several homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) fractions were obtained. Fraction GPS2b with the highest yield was selected for structural characterization by methylation and nuclear magnetic resonance (NMR) analysis. GPS2b was found to be an HG-type pectic polysaccharide (degree of methyl esterification [DE], 51.6%) with low molecular weight ( , 36.8 kDa). It was mainly composed of →4)-α-GalA- (1→ and →4)-α-GalA-6-OMe-(1→. In addition, a minor highly branched RG-I domain was identified in this fraction. The investigation of structural features of tea polysaccharides can provide insights to understand their structure-bioactivity relationship.
茶是一种广受欢迎的饮品，有着长期安全健康的饮用历史。茶多糖是从茶叶中提取的一种生物活性成分，在近几十年中受到越来越多的关注。在本文中，通过热水提取和乙醇沉淀从狗牯脑绿茶中分离出一种酸性多糖——狗牯脑茶多糖（GPS）。经二乙氨基乙基（DEAE）琼脂糖快速流动柱和Sephacryl S - 400柱纯化后，得到了几种同型半乳糖醛酸聚糖（HG）和鼠李糖半乳糖醛酸聚糖-I（RG-I）组分。选择产率最高的组分GPS2b通过甲基化和核磁共振（NMR）分析进行结构表征。发现GPS2b是一种低分子量（ ，36.8 kDa）的HG型果胶多糖（甲酯化度[DE]，51.6%）。它主要由→4)-α-半乳糖醛酸-(1→和→4)-α-半乳糖醛酸-6-OMe-(1→组成。此外，在该组分中鉴定出一个少量的高度分支的RG-I结构域。对茶多糖结构特征的研究可为理解其结构-生物活性关系提供见解。
