Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany.
Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany.
Carbohydr Res. 2019 Sep 1;483:107741. doi: 10.1016/j.carres.2019.107741. Epub 2019 Jul 10.
Flavonoids are commonly abundant, plant-derived polyphenolic compounds which are responsible for color, taste, and antioxidant properties of certain plant based foods. Glucosylation by glucansucrases or other glycosyltransferases/glycoside hydrolases has been described to be a promising approach to modify stability, solubility, bioavailability, and taste profile of flavonoids and other compounds. In this study, we modified and applied a recombinant dextransucrase from Lactobacillus reuteri TMW 1.106 to glucosylate various flavonoids and flavonoid glycosides. The glucoconjugates were subsequently isolated and characterized by using two-dimensional NMR spectroscopy. Efficient glucosylation was achieved for quercetin and its glycosides quercetin-3-O-β-glucoside and rutin. Significant portions of α-glucose conjugates were also obtained for epigallocatechin gallate, dihydromyricetin, and cyanidin-3-O-β-glucoside, whereas glucosylation efficiency was low for naringin and neohesperidin dihydrochalcone. Most of the flavonoids with a catechol or pyrogallol group at the B-ring were predominantly glucosylated at position O4'. However, glycosyl substituents such as β-glucose, rutinose, or neohesperidose were glucosylated at varying positions. Therefore, mutant dextransucrase from L. reuteri TMW 1.106 can be applied for versatile structural modification of flavonoids.
类黄酮是普遍存在的、源自植物的多酚化合物，其负责某些植物性食物的颜色、味道和抗氧化特性。葡聚糖酶或其他糖基转移酶/糖苷水解酶的糖基化已被描述为一种有前途的方法，可以修饰类黄酮和其他化合物的稳定性、溶解度、生物利用度和味道特征。在这项研究中，我们修饰并应用了来自乳杆菌的重组葡聚糖酶 TMW 1.106，以对各种类黄酮和类黄酮糖苷进行葡基化。随后通过二维 NMR 光谱对葡糖苷进行了分离和表征。对于槲皮素及其糖苷槲皮素-3-O-β-葡萄糖苷和芦丁，实现了有效的葡基化。表没食子儿茶素没食子酸酯、二氢杨梅素和矢车菊素-3-O-β-葡萄糖苷也获得了大量的α-葡萄糖缀合物，而橙皮苷和新橙皮苷二氢查尔酮的葡基化效率较低。大多数 B 环上具有邻苯二酚或焦儿茶酚基团的类黄酮主要在 O4'位置上葡基化。然而，糖苷取代基，如β-葡萄糖、芦丁糖或新橙皮糖，在不同位置上进行葡基化。因此，来自乳杆菌 TMW 1.106 的突变型葡聚糖酶可用于广泛修饰类黄酮的结构。
