16290-07-6Relevant articles and documents
Isolation of new flavonol oligosaccharie from the petals of Leucojum vernum L. and Galanthus nivais L
H?rhammer,Wagner,Beck
, p. 896 - 896 (1967)
-
Characterization of flavonoid 7-O-glucosyltransferase from Arabidopsis thaliana
Kim, Jeong Ho,Kim, Bong Gyu,Park, Younghee,Ko, Jae Hyung,Lim, Chae Eun,Lim, Jun,Lim, Yoongho,Ahn, Joong-Hoon
, p. 1471 - 1477 (2006)
Most flavonoids found in plants exist as glycosides, and glycosylation status has a wide range of effects on flavonoid solubility, stability, and bioavailability. Glycosylation of flavonoids is mediated by Family 1 glycosyltransferases (UGTs), which use UDP-sugars, such as UDP-glucose, as the glycosyl donor. AtGT-2, a UGT from Arabidopsis thaliana, was cloned and expressed in Escherichia coli as a gluthatione S-transferase fusion protein. Several compounds, including flavonoids, were tested as potential substrates. HPLC analysis of the reaction products indicated that AtGT-2 transfers a glucose molecule into several different kinds of flavonoids, eriodictyol being the most effective substrate, followed by luteolin, kaempferol, and quercetin. Based on comparison of HPLC retention times with authentic flavonoid 7-O-glucosides and nuclear magnetic resonance spectroscopy, the glycosylation position in the reacted flavonoids was determined to be the C-7 hydroxyl group. These results indicate that AtGT-2 encodes a flavonoid 7-O-glucosyltransferase.
pH-promoted O-α-glucosylation of flavonoids using an engineered α-glucosidase mutant
Li, Chao,Roy, Jetendra Kumar,Park, Ki-Cheul,Cho, Art E.,Lee, Jaeick,Kim, Young-Wan
, (2021/01/04)
Retaining glycosidase mutants lacking its general acid/base catalytic residue are originally termed thioglycoligases which synthesize thio-linked disaccharides using sugar acceptor bearing a nucleophilic thiol group. A few thioglycoligases derived from retaining α-glycosidases have been classified into a new class of catalysts, O-glycoligases which transfer sugar moiety to a hydroxy group of sugar acceptors, resulting in the formation of O-linked glycosides or oligosaccharides. In this study, an efficient O-α-glucosylation of flavonoids was developed using an O-α-glycoligase derived from a thermostable α-glucosidase from Sulfolobus solfataricus (MalA-D416A). The O-glycoligase exhibited efficient transglycosylation activity with a broad substrate spectrum for all kinds of tested flavonoids including flavone, flavonol, flavanone, flavanonol, flavanol and isoflavone classes in yields of higher than 90%. The glucosylation by MalA-D416A preferred alkaline conditions, suggesting that pH-promoted deprotonation of hydroxyl groups of the flavonoids would accelerate turnover of covalent enzyme intermediate via transglucosylation. More importantly, the glucosylation of flavonoids by MalA-D416A was exclusively regioselective, resulting in the synthesis of flavonoid 7-O-α-glucosides as the sole product. Kinetic analysis and molecular dynamics simulations provided insights into the acceptor specificity and the regiospecificity of O-α-glucosylation by MalA-D416A. This pH promoted transglycosylation using O-α-glycoligases may prove to be a general synthesis route to flavonoid O-α-glycosides.
Polyphenolic compounds in Scopolia caucasica Kolesn. ex Kreyer (Solanaceae)
Wolbis, Maria,Nowak, Slawomira,Kicel, Agnieszka
, p. 241 - 246 (2008/09/19)
The qualitative and quantitative determinations of coumarins, phenolic acids and flavonoids in the leaves and underground parts of Scopolia caucasica using paper chromatography and HPLC methods were described. From the leaves of this plant, kaempferol 3-O-(2-glucosyl)-galactoside-7-O-glucoside, kaempferol 3-O-(2-glucosyl)-galactoside and quercetin 3-O-glucoside were isolated and identified by spectroscopic methods (UV, 1H- and 13C-NMR).
