6743-92-6Relevant articles and documents
Highly Promiscuous Flavonoid 3- O-Glycosyltransferase from Scutellaria baicalensis
Wang, Zilong,Wang, Shuang,Xu, Zheng,Li, Mingwei,Chen, Kuan,Zhang, Yaqun,Hu, Zhimin,Zhang, Meng,Zhang, Zhiyong,Qiao, Xue,Ye, Min
supporting information, p. 2241 - 2245 (2019/03/19)
A highly regio-specific and donor-promiscuous 3-O-glycosyltransferase, Sb3GT1 (UGT78B4), was discovered from Scutellaria baicalensis. Sb3GT1 could accept five sugar donors (UDP-Glc/-Gal/-GlcNAc/-Xyl/-Ara) to catalyze 3-O-glycosylation of 17 flavonols, and the conversion rates could be >98%. Five new glycosides were obtained by scaled-up enzymatic catalysis. Molecular modeling and site-directed mutagenesis revealed that G15 and P187 were critical catalytic residues for the donor promiscuity. Sb3GT1 could be a promising catalyst to increase structural diversity of flavonoid 3-O-glycosides.
Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties
Kato, Komei,Ninomiya, Masayuki,Tanaka, Kaori,Koketsu, Mamoru
supporting information, p. 1808 - 1814 (2016/08/02)
Quercetin derivatives are widespread in the plant kingdom and exhibit various biological actions. The aim of this study was to investigate the structure-activity relationships of quercetin derivatives, with a focus on the influence of functional groups and sugar composition on their antioxidant capacity. A series of quercetin derivatives were therefore prepared and assessed for their DPPH radical scavenging properties. Isoquercetin O-gallates were more potent radical scavengers than quercetin. The systematic analysis highlights the importance of the distribution of hydroxy substituents in isoquercetin O-gallates to their potency.
Phenolic constituents of the inflorescences of Sorbus torminalis (L.) Crantz
Olszewska, Monika A.,Roj, Joanna Marta
experimental part, p. 151 - 157 (2012/05/04)
Torminaloside, a new acylated flavonol glycoside (3,5,7,4′- tetrahydroxy-3′-methoxyflavone-3-O-[6″-O-(3?-hydroxy- 3?-methylglutaroyl)]-β-d-galactopyranoside, 6), together with five further methoxylated flavones 1-5, hyperoside (7), isoquercitrin (8), chlorogenic acid (9) and neochlorogenic acid (10), were isolated for the first time from Sorbus torminalis (L.) Crantz. The structures of the isolates were elucidated by extensive spectroscopic studies, including UV, IR, 1D- and 2D-NMR, LSI-MS and HR-LSI-MS experiments. In addition to torminaloside, three further flavonoids: 5,7,4′-trihydroxy-3′-methoxyflavone-7-O-β-d- glucopyranoside (1), 3,5,7,4′-tetrahydroxy-8,3′-dimethoxyflavone-3- O-β-d-glucopyranoside (2), and 3,5,7,4′-tetrahydroxy-3′- methoxyflavone-3-O-β-d-galactopyranoside (4) were found for the first time in the genus Sorbus.