- Highly Promiscuous Flavonoid 3- O-Glycosyltransferase from Scutellaria baicalensis
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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.
- Wang, Zilong,Wang, Shuang,Xu, Zheng,Li, Mingwei,Chen, Kuan,Zhang, Yaqun,Hu, Zhimin,Zhang, Meng,Zhang, Zhiyong,Qiao, Xue,Ye, Min
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supporting information
p. 2241 - 2245
(2019/03/19)
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- Efficient Synthesis of Crocins from Crocetin by a Microbial Glycosyltransferase from Bacillus subtilis 168
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Crocins are the most important active ingredient found in Crocus sativus, a well-known "plant gold". The glycosyltransferase-catalyzed glycosylation of crocetin is the last step of biosynthesizing crocins and contributes to their structural diversity. Crocin biosynthesis is now hampered by the lack of efficient glycosyltransferases with activity toward crocetin. In this study, two microbial glycosyltransferases (Bs-GT and Bc-GTA) were successfully mined based on the comprehensive analysis of the PSPG motif and the N-terminal motif of the target plant-derived UGT75L6 and Cs-GT2. Bs-GT from Bacillus subtilis 168, an enzyme with a higher activity of glycosylation toward crocetin than that of Bc-GTA, was characterized. The efficient synthesis of crocins from crocetin catalyzed by microbial GT (Bs-GT) was first reported with a high molecular conversion rate of 81.9%, resulting in the production of 476.8 mg/L of crocins. The glycosylation of crocetin on its carboxyl groups by Bs-GT specifically produced crocin-5 and crocin-3, the important rare crocins.
- Ding, Fangyu,Liu, Feng,Shao, Wenming,Chu, Jianlin,Wu, Bin,He, Bingfang
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p. 11701 - 11708
(2018/11/21)
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- Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties
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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.
- Kato, Komei,Ninomiya, Masayuki,Tanaka, Kaori,Koketsu, Mamoru
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supporting information
p. 1808 - 1814
(2016/08/02)
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- NOVEL FLAVANONE DERIVATIVE
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Provided is a novel antimicrobial agent. More specifically, provided is a novel antimicrobial agent capable of effectively acting on various resistant bacteria such as VSSA, MRSA, VISA, VRE, and VRSA. A novel flavanone derivative having a six-membered monosaccharide derivative, specifically, a glucose derivative or a galactose derivative is capable of effectively acting on the bacteria. More specifically, a compound represented by the general formula (I) is capable of effectively acting on the bacteria. (In the formula: X represents a six-membered monosaccharide derivative; and Y is substituted by a hydroxyl group.)
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Page/Page column 35
(2012/06/18)
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- Quercetin diacylglycoside analogues showing dual inhibition of DNA gyrase and topoisomerase IV as novel antibacterial agents
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A structure-guided molecular design approach was used to optimize quercetin diacylglycoside analogues that inhibit bacterial DNA gyrase and topoisomerase IV and show potent antibacterial activity against a wide spectrum of relevant pathogens responsible f
- Hossion, Abugafar M. L.,Zamami, Yoshito,Kandahary, Rafiya K.,Tsuchiya, Tomofusa,Ogawa, Wakano,Iwado, Akimasa,Sasaki, Kenji
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experimental part
p. 3686 - 3703
(2011/08/03)
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- Functional characterization of a UDP-glucose:flavonoid 3-O- glucosyltransferase from the seed coat of black soybean (Glycine max (L.) Merr.)
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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.
- Kovinich, Nik,Saleem, Ammar,Arnason, John T.,Miki, Brian
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experimental part
p. 1253 - 1263
(2011/04/22)
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- BENZOPYRANONE DERIVATIVES AND THEIR USE AS ANTI-CORONAVIRAL AGENTS
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The invention relates to pharmaceutical compositions comprising benzopyranone derivatives for the treatment of Severe Acute Respiratory Syndrome (SARS).
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Page/Page column 33
(2008/06/13)
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- Binding interaction of quercetin-3-β-galactoside and its synthetic derivatives with SARS-CoV 3CLpro: Structure-activity relationship studies reveal salient pharmacophore features
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The 3C-like protease (3CLpro) of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is one of the most promising targets for discovery of drugs against SARS, because of its critical role in the viral life cycle. In this study,
- Chen, Lili,Li, Jian,Luo, Cheng,Liu, Hong,Xu, Weijun,Chen, Gang,Liew, Oi Wah,Zhu, Weiliang,Puah, Chum Mok,Shen, Xu,Jiang, Hualiang
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p. 8295 - 8306
(2007/10/03)
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- Cloning and functional characterisation of two regioselective flavonoid glucosyltransferases from Beta vulgaris
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Two full-length cDNAs encoding flavonoid-specific glucosyltransferases, UGT73A4 and UGT71F1, were isolated from a cDNA library of Beta vulgaris (Amaranthaceae) cell suspension cultures. They displayed high identity to position-specific betanidin and flavonoid glucosyltransferases from Dorotheanthus bellidiformis (Aizoaceae) and to enzymes with similar substrate specificities from various plant families. The open reading frame of the sequences encode proteins of 476 (UGT73A4) and 492 (UGT71F1) amino acids with calculated molecular masses of 54.07 kDa and 54.39 kDa, and isoelectric points of 5.8 and 5.6, respectively. Both enzymes were functionally expressed in Escherichia coli as His- and GST-tagged proteins, respectively. They exhibited a broad substrate specificity, but a distinct regioselectivity, glucosylating a variety of flavonols, flavones, flavanones, and coumarins. UGT73A4 showed a preference for the 4′- and 7-OH position in the flavonoids, whereas UGT71F1 preferentially glucosylated the 3- or the 7-OH position. Glucosylation of betanidin, the aglycone of the major betacyanin, betanin, in B. vulgaris was also observed to a low extent by both enzymes. Several O-glycosylated vitexin derivatives isolated from leaves of young B. vulgaris plants and rutin obtained from B. vulgaris tissue culture are discussed as potential endogenous products of UGT73A4 and UGT71F1. The results are analyzed with regard to evolution and specificity of plant natural product glucosyltransferases.
- Isayenkova, Judith,Wray, Victor,Nimtz, Manfred,Strack, Dieter,Vogt, Thomas
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p. 1598 - 1612
(2008/02/12)
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- Synthesis and biological evaluation of flavonoids as vasorelaxant agents
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Several 5,7-dihydroxyflavone and quercetin 3-O-glycosides have been synthesized and evaluated for vasorelaxant activity. A logP-activity relationship amongst flavonoids was suggested.
- Chen, Zhiwei,Hu, Yongzhou,Wu, Haohao,Jiang, Huidi
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p. 3949 - 3952
(2007/10/03)
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- Isolation and antioxidant activity of galloyl flavonol glycosides from the seashore plant, Pemphis acidula.
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Four kinds of galloyl flavonol glycosides were found in the leaf extract of Pemphis acidula, a plant growing on the subtropical seashore. Their chemical structures were elucidated to be quercetin or kaempferol 6 -O-galloyl-beta-D-glycosides by using spectroscopic and chemical analyses. One of the flavonols, kaempferol-3-O-(6-O-galloyl-beta-D-galactopyranoside), was newly isolated from natural sources and its structure was completely determined in this investigation. The antioxidant-related activities of the galloyl flavonoids were examined by the DPPH antiradical activity, inhibition of methyl linoleate oxidation, and inhibition of oxidative cell death. These results were compared with those of the corresponding non-galloylated flavonol glycosides and their aglycones. The galloyl flavonoids showed more efficient activity than that of the corresponding flavonol glycosides, but not more than that of the corresponding aglycones in the three assays applied.
- Masuda,Iritani,Yonemori,Oyama,Takeda
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p. 1302 - 1309
(2007/10/03)
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- GALLOYLHOMOARBUTIN AND RELATED POLYPHENOLS FROM PYROLA INCARNATA
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A new polyphenol, 6-O-galloylhomoarbutin was isolated from Pyrola incarnata, along with (+)-catechin, (-)-epicatechin gallate, procyanidin B1, B3, B2-3'-O-gallate, B2-3,3'-di-O-gallate, hyperin and hyperin-2"-O-gallate.Hyperin-2"-O-gallate, one of the main components, showed strong tanning activity. - Keywords: Pyrola incarnata; Pyrolaceae; polyphenols; 6-O-galloylhomoarbutin; 2"-O-galloylhyperin; procyanidins.
- Yazaki, Kazufumi,Shida, Shoko,Okuda, Takuo
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p. 607 - 610
(2007/10/02)
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- A Flavonol-diglycoside from Melastoma melabathricum
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A new flavonol-diglycoside was isolated from the methanolic extract of the aerial parts of Melastoma melabathricum.Its structure was established as quercetin-3-O-α-L-rhamnosyl-(1->2)-β-D-galactoside on the basis of physical and chemical evidences.
- Dinda, B.,Saha, M. K.
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p. 209 - 211
(2007/10/02)
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