Instituto de Catálisis y Petroleoquímica , Consejo Superior de Investigaciones Científicas (CSIC) , 28049 Madrid , Spain.
Center for Cooperative Research in Biosciences , Parque Científico Tecnológico de Bizkaia , 48160 Derio , Biscay , Spain.
J Agric Food Chem. 2018 Jul 18;66(28):7402-7408. doi: 10.1021/acs.jafc.8b02143. Epub 2018 Jul 9.
The glycosylation of plant polyphenols may modulate their solubility and bioavailability and protect these molecules from oxygen, light degradation, and during gastrointestinal transit. In this work, the synthesis of various α-glucosyl derivatives of (-)-epigallocatechin gallate, the predominant catechin in green tea, was performed in water at 50 °C by a transglycosylation reaction catalyzed by cyclodextrin glycosyltransferase from Thermoanaerobacter sp. The molecular weight of reaction products was determined by high-performance liquid chromatography coupled to mass spectrometry. Using hydrolyzed potato starch as a glucosyl donor, two main monoglucosides were obtained with conversion yields of 58 and 13%, respectively. The products were isolated and chemically characterized by combining two-dimensional nuclear magnetic resonance methods. The major derivative was epigallocatechin gallate 3'- O-α-d-glucopyranoside (1), and the minor derivative was epigallocatechin gallate 7- O-α-d-glucopyranoside (2).
植物多酚的糖基化可能调节其溶解性和生物利用度，并保护这些分子免受氧气、光照降解以及在胃肠道转运过程中的影响。在这项工作中，通过嗜热厌氧菌来源的环糊精糖基转移酶在 50°C 的水中进行转糖基化反应，合成了绿茶中主要儿茶素 (-)-表没食子儿茶素没食子酸酯的各种 α-葡萄糖苷衍生物。通过高效液相色谱-质谱联用确定了反应产物的分子量。使用水解马铃薯淀粉作为葡萄糖供体，分别得到转化率为 58%和 13%的两种主要的单葡糖苷。通过二维核磁共振方法相结合的方式对产物进行了分离和化学表征。主要的衍生物是表没食子儿茶素没食子酸酯 3'-O-α-d-吡喃葡萄糖苷（1），次要的衍生物是表没食子儿茶素没食子酸酯 7-O-α-d-吡喃葡萄糖苷（2）。
