5041-82-7Relevant academic research and scientific papers
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.
Synthesis of flavonol 3-O-glycoside by UGT78D1
Ren, Guangxiang,Hou, Jingli,Fang, Qinghong,Sun, Hong,Liu, Xiaoyan,Zhang, Lianwen,Wang, Peng George
, p. 425 - 432 (2012/11/13)
Glycosylation is an important method for the structural modification of various flavonols, resulting in the glycosides with increased solubility, stability and bioavailability compared with the corresponding aglycone. From the physiological point of view, glycosylation of plant flavonoids is of importance and interest. However, it is notoriously complicated that flavonols such as quercetin, kaempferol and myricetin, are glucosylated regioselectively at the specific position by chemical method. Compared to the chemical method, enzymatic synthesis present several advantages, such as mild reaction condition, high stereo or region selectivity, no protection/deprotection and high yield. UGT78D1 is a flavonol-specific glycosyltransferase, responsible for transferring rhamnose or glucose to the 3-OH position in vitro. In this study, the activity of UGT78D1 was tested against 28 flavonoids acceptors using UDP-glucose as donor nucleoside in vitro, and 5 acceptors, quercetin, myricetin, kaempferol, fisetin and isorhamnetin, were discovered to be glucosylated at 3-OH position. Herein, the small-scale 3-O-glucosylated quercetin, kaempferol and myricetin were synthesized by UGT78D1 and their chemical structures were confirmed by 1H and 13C nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). Springer Science+Business Media, LLC 2012.
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.
Characterization of a Vitis vinifera cv. Cabernet Sauvignon 3′,5′-O-methyltransferase showing strong preference for anthocyanins and glycosylated flavonols
Luecker, Joost,Martens, Stefan,Lund, Steven T.
experimental part, p. 1474 - 1484 (2010/10/21)
At ripening initiation in red grapevine (Vitis vinifera) berries, the exocarp turns color from green to red and then to purple due to the accumulation and extent of methylation of anthocyanins. The accumulation of transcripts encoding an O-methyltransferase was recently shown to be closely correlated with the onset of ripening and the degree of blue/purple pigmentation in grapevine berries; however, the biochemical function of this gene has remained uncharacterized. In this study, an O-methyltransferase cDNA that showed a distinct expression pattern when compared to closely related sequences was expressed in Escherichia coli and enzyme assays were carried out with a broad array of anthocyanin and other flavonoid substrates. We demonstrate that this enzyme carries out 3′,5′-O-methylation of anthocyanins and flavonol compounds in vitro, which are known to be present in grape berries, with a preference for glycosylated substrates. The highest relative specific activity for the enzyme was found with delphinidin 3-O-glucoside as substrate. The enzyme is not able to methylate flavan type skeletons with chiral centers, such as either catechins or dihydroquercetin. The enzyme showed negligible specific activity for caffeoyl-CoA, compared to flavonol and anthocyanin substrates. Phylogenetic analysis of the O-methyltransferase suggests that it may be a member of a distinct subclass of Type 2 bivalent metal-dependent S-adenosyl-methionine O-methyltransferases.
Biological synthesis of isorhamnetin 3-O-glucoside using engineered glucosyltransferase
Kim, Bong-Gyu,Sung, Su Hyun,Jung, Na Ri,Chong, Youhoon,Ahn, Joong-Hoon
experimental part, p. 194 - 199 (2010/10/18)
The gene for one of the glycosyltransferases from Populus deltoids, PGT-3, was cloned and was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Various flavonoids were used as potential substrates of the purified recombinant PGT-3. Flavones having two adjacent hydroxyl groups were served as substrate. The regioselectivity of PGT-3 depends on the hydroxyl groups of the substrate. Flavones having two adjacent hydroxyl groups in the B ring were glucosylated at the 4′-hydroxyl group. However, PGT-3 transferred a glucose group to the 3-hydroxyl group of isorhamnetin. Molecular modeling and docking and site-directed mutagenesis were carried out to engineer a PGT-3 having a specificity for isorhamnetin but not for quercetin. Glu82Leu turned out to display this activity. Using the Glu82Leu mutant and a quercetin 3′- O-methyltransferase, isorhamnetin 3- O-glucoside was synthesized.
Functional characterization of a UDP-glucose:flavonoid 3-O- glucosyltransferase from the seed coat of black soybean (Glycine max (L.) Merr.)
Kovinich, Nik,Saleem, Ammar,Arnason, John T.,Miki, Brian
experimental part, p. 1253 - 1263 (2011/04/22)
The seed coats of black soybean (Glycine max (L.) Merr.) accumulate red (cyanidin-), blue (delphinidin-), purple (petunidin-), and orange (pelargonidin-based) anthocyanins almost exclusively as 3-O-glucosides; however, the responsible enzyme has not been identified. In this study, the full-length cDNA which encodes the enzyme that catalyzes the final step in anthocyanin biosynthesis, namely UDP-glucose:flavonoid 3-O-glucosyltransferase (UGT78K1), was isolated from the seed coat tissue of black soybean using rapid amplification of cDNA ends (RACE). Of the 28 flavonoid substrates tested, the purified recombinant protein glucosylated only anthocyanidins and flavonols, and demonstrated strict 3-OH regiospecificity. Galactose could also be transferred with relatively low activity to the 3-position of cyanidin or delphinidin in vitro. These findings are consistent with previous reports of mainly 3-O-glucosylated and minor amounts of 3-O-galactosylated anthocyanins in the seed coat of black soybean. The recombinant enzyme exhibited pronounced substrate inhibition by cyanidin at 100 μM acceptor concentration. Transfer of UGT78K1 into the Arabidopsis T-DNA mutant (ugt78d2) deficient in anthocyanidin and flavonol 3-O-glucosyltransferase activity, restored the accumulation of anthocyanins and flavonols, suggesting the in vivo function of the enzyme as a flavonoid 3-O-glucosyltransferase. Genomic and phylogenetic analyses suggest the existence of three additional soybean sequences with high similarity to UGT78K1. RT-PCR confirmed the co-expression of one of these genes (Glyma08g07130) with UGT78K1 in the seed coat of black soybean, suggesting possible functional redundancies in anthocyanin biosynthesis in this tissue.
N-allylisonitrarine and narcissin from plants of the Nitraria genus
Tulyaganov,Nazarov,Makhmudov,Vdovin,Abdullaev
, p. 470 - 473 (2007/10/03)
The new alkaloid N-allylisonitrarine was isolated from the aerial part of Nitraria schoberi L. Its structure was established using spectral data and chemical transformations. Leaves of Nitraria komarovii contain the flavonoid narcissin. Its 1H
Flavonoid and benzophenone glycosides from Coleogyne ramosissima
Ito, Hideyuki,Nishitani, Eisei,Konoshima, Takao,Takasaki, Midori,Kozuka, Mutsuo,Yoshida, Takashi
, p. 695 - 700 (2007/10/03)
A benzophenone glucoside and two flavonol glycosides were isolated together with 27 known polyphenols from the aerial parts of Coleogyne ramosissima, and their structures were elucidated by spectroscopic and chemical methods as iriflophenone 2-O-β-glucopyranoside, isorhamnetin 3-O-2(G)-rhamnopyranosylrutinoside-7-O-α-rhamnopyranoside and limocitrin 3-O-rutinoside-7-O-β-glucopyranoside, respectively. (C) 2000 Elsevier Science Ltd.
