- Isolation and characterization of a glycosyltransferase with specific catalytic activity towards flavonoids from Tripterygium wilfordii
-
Flavonoids are important secondary metabolites that exist in many medicinal plants. Flavonoid glycosyltransferases can transfer sugar moieties to their parent rings, producing various flavonoid glycosides with significant pharmacological activities. Here, we report the molecular cloning of the O-glycosyltransferase TwUGT2 from Tripterygium wilfordii and its catalytic activity was explored by heterologous expression in E. coli. The results showed that TwUGT2 has specific glycosyltransferase activity towards C-3 and 7 hydroxyl groups of flavonoids, thereby converting quercetin and pinocembrin into isoquercitrin and pinocembrin 7-O-beta-D-glucoside, respectively. The identification of TwUGT2 will provide a useful molecular tool for synthetic biology and contribute to drug discovery. (Figure presented.).
- Lu, Yun,Ma, Bao-Wei,Gao, Jie,Tu, Li-Chan,Hu, Tian-Yuan,Zhou, Jia-Wei,Liu, Yuan,Tu, Yu-He,Lin, Zhao-Shou,Huang, Lu-Qi,Gao, Wei
-
-
Read Online
- Glucose tolerance-improving activity of helichrysoside in mice and its structural requirements for promoting glucose and lipid metabolism
-
An acylated flavonol glycoside, helichrysoside, at a dose of 10 mg/kg/day per os for 14 days, improved the glucose tolerance in mice without affecting the food intake, visceral fat weight, liver weight, and other plasma parameters. In this study, using hepatoblastoma-derived HepG2 cells, helichrysoside, trans-tiliroside, and kaempferol 3-O-β-D-glucopyranoside enhanced glucose consumption from the medium, but their aglycones and p-coumaric acid did not show this activity. In addition, several acylated flavonol glycosides were synthesized to clarify the structural requirements for lipid metabolism using HepG2 cells. The results showed that helichrysoside and related analogs significantly inhibited triglyceride (TG) accumulation in these cells. The inhibition by helichrysoside was more potent than that by other acylated flavonol glycosides, related flavonol glycosides, and organic acids. As for the TG metabolism-promoting activity in high glucose-pretreated HepG2 cells, helichrysoside, related analogs, and their aglycones were found to significantly reduce the TG contents in HepG2 cells. However, the desacyl flavonol glycosides and organic acids derived from the acyl groups did not exhibit an inhibitory impact on the TG contents in HepG2 cells. These results suggest that the existence of the acyl moiety at the 6'' position in the D-glucopyranosyl part is essential for glucose and lipid metabolism-promoting activities.
- Hori, Yuichiro,Miki, Yoshinobu,Morikawa, Toshio,Muraoka, Osamu,Nagatomo, Akifumi,Ninomiya, Kiyofumi,Oka, Takahiro,Shibano-Kitahara, Megumi,Taira, Norihisa
-
-
Read Online
- Enzymatic synthesis of novel quercetin sialyllactoside derivatives
-
Quercetin and its derivatives are important flavonols that show diverse biological activity, such as antioxidant, anticarcinogenic, anti-inflammatory, and antiviral activities. Adding different substituents to quercetin may change the biochemical activity
- Bae, Jae Yoon,Darsandhari, Sumangala,Han, Jang Mi,Jung, Hye Jin,Pandey, Ramesh Prasad,Rha, Chan-Su,Shrestha, Biplav,Sohng, Jae Kyung,Yamaguchi, Tokutaro
-
-
Read Online
- Diastereoselective Synthesis of Thioglycosides via Pd-Catalyzed Allylic Rearrangement
-
Stereoselective glycosylation is challenging in carbohydrate chemistry. Herein, stereoselective thioglycosylation of glycals via palladium-catalyzed allylic rearrangement yields various substituents on α-isomer thioglycosides. Two comprehensive series of aryl and benzyl thioglycosides were obtained via a combination of thiosulfates with glycals derived from glucose, arabinose, galactose, and rhamnose. Furthermore, diosgenyl α-l-rhamnoside and isoquercitrin achieved selectivity via stereospecific [2,3]-sigma rearrangements of α-sulfoxide-rhamnoside and α-sulfoxide-glucoside, respectively.
- Jiang, Xuefeng,Li, Jiagen,Wang, Ming
-
supporting information
p. 9053 - 9057
(2021/11/30)
-
- Highly Promiscuous Flavonoid 3- O-Glycosyltransferase from Scutellaria baicalensis
-
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
-
supporting information
p. 2241 - 2245
(2019/03/19)
-
- On the Catalytic Activity of a GT1 Family Glycosyltransferase from Streptomyces venezuelae ISP5230
-
GT1 family glycosyltansferase, Sv0189, from Streptomyces venezuelae ISP5230 (ATCC 10721) was characterized. The recombinantly produced protein Sv0189 possessed UDP-glycosyltransferase activity. Screening, using an assay employing unnatural nitrophenyl glycosides as activated donors, resulted in the discovery of a broad substrate scope with respect to both acceptor molecules and donor sugars. In addition to polyphenols, including anthraquinones, simple aromatics containing primary or secondary alcohols, a variety of complex natural products and synthetic drugs were glucosylated or xylosylated by Sv0189. Regioselectivity was established through the isolation and characterization of glucosylated products. Sv0189 and homologous proteins are widely distributed among Streptomyces species, and their apparent substrate promiscuity reveals potential for their development as biocatalysts for glycodiversification.
- Forget, Stephanie M.,Shepard, Sydney B.,Soleimani, Ebrahim,Jakeman, David L.
-
p. 11482 - 11492
(2019/10/02)
-
- Isoquercetin and derivative and application and preparation methods thereof
-
The invention provides an isoquercetin and derivative. The structural formula of the isoquercetin and derivative is shown as the formula I, wherein n=1-9, and R is selected from Glu, Rha, Gal, Xyl orAll. The isoquercetin and derivative solves the problem of poor solubility of rutin and quercetin as well as in vivo digestion and absorption of rutin, improves the bioavailability of isoquercetin andpolysaccharide isoquercetin and achieves significant therapeutic effects on prevention and treatment of osteoporosis and hyperlipidemia.
- -
-
Paragraph 0023; 0024
(2019/04/09)
-
- An alkali tolerant α-L-rhamnosidase from Fusarium moniliforme MTCC-2088 used in de-rhamnosylation of natural glycosides
-
Analkali tolerant α-L-rhamnosidase has been purified to homogeneity from the culture filtrate of a new fungal strain, Fusarium moniliforme MTCC-2088, using concentration by ultrafiltration and cation exchange chromatography on CM cellulose column. The molecular mass of the purified enzyme has been found to be 36.0 kDa using SDS-PAGE analysis. The Km value using p-nitrophenyl-α-L-rhamnopyranoside as the variable substrate in 0.2 M sodium phosphate buffer pH10.5 at50 °C was 0.50 mM. The catalytic rate constant was15.6 s?1giving the values of kcat/Km is 3.12 × 104M?1 s?1. The pH and temperature optima of the enzyme were 10.5 and 50 °C, respectively. The purified enzyme had better stability at 10 °C in basic pH medium. The enzyme derhamnosylated natural glycosides like naringin to prunin, rutin to isoquercitrin and hesperidin to hesperetin glucoside. The purified α-L-rhamnosidase has potential for enhancement of wine aroma.
- Kumar, Dhirendra,Yadav, Sarita,Yadava, Sudha,Yadav
-
-
- Efficient Synthesis of Crocins from Crocetin by a Microbial Glycosyltransferase from Bacillus subtilis 168
-
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
-
p. 11701 - 11708
(2018/11/21)
-
- Multi-stage solvent extraction in the application of enzymatic synthesis isoquercitrin
-
The invention relates to application of a multistage solvent extraction method in enzymatic synthesis of isoquercitrin. The application comprises the steps of dissolving rutin in a 1g/L glycine-NaOH buffer solution with the pH value of 9.0, adding ionic liquid [Bmim][BF4] of a volume which is 10% that of the solution and a hesperidinase solution so as to form a reaction system, and carrying out oscillating culture at the constant temperature of 40 DEG C, so as to obtain a rutin hydrolyzate, wherein the pH value of an ionic liquid cosolvent system, namely the rutin hydrolyzate, is 2.0-7.0; mixing the rutin hydrolyzate and an extractant, oscillating in a water bath at a constant temperature, carrying out solvent extraction under the conditions that the phase ratio of an organic phase to an aqueous phase is 0.2-2.0 and the extraction time is 10-150 minutes, then, calculating a theoretical stage number by adopting a multistage countercurrent extraction formula, and screening out the best extraction conditions according to the extractant of the minimum required ratio and the theoretical stage number when complete extraction is achieved. According to the application, the operation is simple and convenient, the process is easy to operate, the difficulty and cost of late-stage purification of biological reaction are reduced, and the recovery rate and purity of products are improved.
- -
-
Paragraph 0028; 0029; 0030
(2017/02/23)
-
- Effects of Functional Groups and Sugar Composition of Quercetin Derivatives on Their Radical Scavenging Properties
-
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
-
supporting information
p. 1808 - 1814
(2016/08/02)
-
- Ultrafast synthesis of isoquercitrin by enzymatic hydrolysis of rutin in a continuous-flow microreactor
-
Isoquercitrin is a rare flavonol glycoside with a wide range of biological activities and is a key synthetic intermediate for the production of enzymatically modified isoquercitrin. In order to establish an ultrafast bioprocess for obtaining isoquercitrin, a novel continuous flow biosynthesis of isoquercitrin using the hesperidinase-catalyzed hydrolysis of rutin in a glass-polydimethylsiloxane (PDMS) microreactor was first performed. Using the developed microchannel reactor (200 μm width, 50 μm depth and 2 m length) with one T-shaped inlet and one outlet, the maximum yield of isoquercitrin (98.6%) was achieved in a short time (40 min) under the following optimum conditions: rutin concentration at 1 g L-1, hesperidinase concentration at 0.1 g mL-1, reaction temperature 40°C, and a flow rate of 2 μL min-1. The value of the activation energy, Ea, of the enzymatic reaction was 4.61 kJ mol-1, and the reaction rate and volume productivity were approximately 16.1-fold and 30% higher, respectively, than those in a batch reactor were. Thus, the use of a continuous-flow microreactor for the enzymatic hydrolysis of rutin is an efficient and simple approach to achieve a relatively high yield of isoquercitrin.
- Wang, Jun,Gong, An,Gu, Shuangshuang,Cui, Hongsheng,Wu, Xiangyang
-
p. 853 - 866
(2015/08/24)
-
- Ultrafast synthesis of isoquercitrin by enzymatic hydrolysis of rutin in a continuous-flow microreactor
-
Isoquercitrin is a rare flavonol glycoside with a wide range of biological activities and is a key synthetic intermediate for the production of enzymatically modified isoquercitrin. In order to establish an ultrafast bioprocess for obtaining isoquercitrin, a novel continuous flow biosynthesis of isoquercitrin using the hesperidinase-catalyzed hydrolysis of rutin in a glass-polydimethylsiloxane (PDMS) microreactor was first carried out. Using the developed microchannel reactor (200 μm width, 50 μm depth, and 2 m length) with one T-shaped inlet and one outlet, the maximum yield of isoquercitrin (98.6 %) was achieved in a short time (40 min) under the following optimum conditions: rutin concentration at 1 g L-1, hesperidinase concentration at 0.1 g mL-1, reaction temperature at 40 °C, and a flow rate at 2 μL min-1. The activation energy value Ea of the enzymatic reaction was 4.61 kJ mol-1, and the reaction rate and volumetric productivity were approximately 16.1-fold and 30 % higher, respectively, than those in the batch reactor. Thus, the use of a continuous-flow microreactor for the enzymatic hydrolysis of rutin is an efficient and simple approach to achieve a relative high yield of isoquercitrin.
- Wang, Jun,Gong, An,Gu, Shuangshuang,Cui, Hongsheng,Wu, Xiangyang
-
-
- Synthesis of quercetin glycosides and their melanogenesis stimulatory activity in B16 melanoma cells
-
4′-O-β-d-Glucopyranosyl-quercetin-3-O-β-d-glucopyranosyl- (1→4)-β-d-glucopyra-noside (3) was isolated from Helminthostachys zeylanica root extract as a melanogenesis acceleration compound and was synthesized using rutin as the starting material Related compounds were also synthesized to understand the structure-activity relationships in melanin biosynthesis Melanogenesis activities of the glycosides were determined by measuring intracellular melanin content in B16 melanoma cells Among the synthesized quercetin glycosides, quercetin-3-O-β-d-glucopyranoside (1), quercetin-3-O-β-d-glucopyranosyl-(1→4)-β-d-glucopyranoside (2), and 3 showed more potent intracellular melanogenesis acceleration activities than theophyline used as positive control in a dose-dependent manner with no cytotoxic effect
- Yamauchi, Kosei,Mitsunaga, Tohru,Batubara, Irmanida
-
p. 937 - 944
(2014/02/14)
-
- Comparing the acceptor promiscuity of a Rosa hybrida glucosyltransferase RhGT1 and an engineered microbial glucosyltransferase OleDPSA toward a small flavonoid library
-
Glycosylation is a widespread modification of plant secondary metabolites, and catalyzed by a superfamily of enzymes called UDP-glycosyltransferases (UGTs). UGTs are often involved in late biosynthetic steps and show broad substrate specificity or regioselectivity. In this study, the acceptor promiscuity of a Rosa hybrid UGT RhGT1 and an evolved microbial UGT OleD PSA toward a small flavonoid library was probed and compared. Interestingly, RhGT1 showed comparable acceptor promiscuity in comparison with OleDPSA, though the acceptor binding pocket of the latter is much more open and large. This clearly indicates that stabilization of the acceptor position by suitable hydrophobic interactions is important for the specificity or regioselectivity determination as well as overall fit of the acceptor into a 'big enough' binding pocket. This also poses a challenge for structure-based UGT engineering to alter the glucosylation pattern of flavonoids.
- Wang, Lu,Han, Weiqing,Xie, Chenying,Hou, Jingli,Fang, Qinghong,Gu, Jianchun,Wang, Peng George,Cheng, Jiansong
-
supporting information
p. 73 - 77
(2013/03/14)
-
- NOVEL FLAVANONE DERIVATIVE
-
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.)
- -
-
Page/Page column 19; 22
(2012/06/18)
-
- Synthesis of flavonol 3-O-glycoside by UGT78D1
-
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.
- Ren, Guangxiang,Hou, Jingli,Fang, Qinghong,Sun, Hong,Liu, Xiaoyan,Zhang, Lianwen,Wang, Peng George
-
p. 425 - 432
(2012/11/13)
-
- Regiospecific synthesis of quercetin O-β-d-glucosylated and O-β-d-glucuronidated isomers
-
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.
- Kajjout, Mohammed,Rolando, Christian
-
p. 4731 - 4741
(2011/07/08)
-
- Synthesis of quercetin 3-O-[6"-O-(trans-p-coumaroyl)]-β-D- Glucopyranoside
-
This report describes the efficient synthesis of quercetin 3-O-[6"-O-(trans-pcoumaroyl)]- β-D-glucopyranoside 1 (isoquercitrin coumarate), an acylated quercetin glycoside possessing antihypertensive, antidiabetic, and tyrosinase inhibitory activities. The synthesis is initiated from commercially available quercetin via regioselective benzylation of quercetin to produce 4', 7-di-O-benzylquercetin (4). Through 4, 1 was successfully achieved via selective β-glycosylation of the 3-OH, acylation of 6"-OH, and finally debenzylation via catalytic transfer hydrogenation. Taylor & Francis Group, LLC.
- Ren, Xuhong,Shen, Liu-Lan,Muraoka, Osamu,Cheng, Maosheng
-
p. 119 - 131
(2012/01/13)
-
- Transformation of rutin to antiproliferative quercetin-3-glucoside by aspergillus niger
-
The flavonol quercetin in plants and foods occurs predominantly in the form of glycoside whose sugar moiety affects the bioavailability and the mechanism of its biological activities. The antiproliferative activities of quercetin derivatives such as quercetin aglycone, quercetin-3-ss-D-glucoside (Q3G), and rutin were compared using six different cancer cell lines including colon, breast, hepatocellular, and lung cancer. The IC50 value of Q3G ranged between 15 and 25 μM in HT-29, HCT 116, MCF-7, HepG2, and A549 cells. In these five cell lines, Q3G showed the most potent growth inhibition, whereas rutin showed the least potency. Transformation of rutin to Q3G was conducted by controlling R-L-rhamnosidase and ss-D-glucosidase activities from crude enzyme extract of Aspergillus niger. Carbon sources during culture and transformation conditions such as pH, temperature, and heatstability were optimized. After 4 h biotransformation, 99% of rutin was transformed to Q3G and no quercetin was detected. This study presented an efficient biotransformation for the conversion of rutin to Q3G which was newly shown to have more potent antiproliferative effect than quercetin and rutin. 2010 American Chemical Society.
- Ju You, Hyun,Jin Ahn, Hyung,Ji, Geun Eog
-
experimental part
p. 10886 - 10892
(2011/06/21)
-
- Design, synthesis, and biological evaluation of a novel series of quercetin diacylglucosides as potent anti-MRSA and anti-VRE agents
-
A series of novel quercetin diacylglucosides were designed and first synthesized by Steglich esterification on the basis of MRSA strains inhibiting natural compound A. The in vitro inhibition of different multi-drug resistant bacterial strains and Escherichia coli DNA gyrase B was investigated. In the series, compound 10h was up to 128-fold more potent against vancomycin-resistant enterococci and more effective than A, which represents a promising new candidate as a potent anti-MRSA and anti-VRE agent.
- Hossion, Abugafar M.L.,Otsuka, Nao,Kandahary, Rafiya K.,Tsuchiya, Tomofusa,Ogawa, Wakano,Iwado, Akimasa,Zamami, Yoshito,Sasaki, Kenji
-
supporting information; experimental part
p. 5349 - 5352
(2010/10/18)
-
- Functional characterization of a UDP-glucose:flavonoid 3-O- glucosyltransferase from the seed coat of black soybean (Glycine max (L.) Merr.)
-
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
-
experimental part
p. 1253 - 1263
(2011/04/22)
-
- Anti-Atherogenic Composition
-
Disclosed is an anti-atherogenic composition or an atherosclerosis progression inhibitory composition which can be used effectively for preventing or ameliorating atherosclerosis. The anti-atherogenic composition or atherosclerosis progression inhibitory composition comprises an enzyme-treated isoquercitrin as the active ingredient.
- -
-
Page/Page column 5
(2008/12/07)
-
- BENZOPYRANONE DERIVATIVES AND THEIR USE AS ANTI-CORONAVIRAL AGENTS
-
The invention relates to pharmaceutical compositions comprising benzopyranone derivatives for the treatment of Severe Acute Respiratory Syndrome (SARS).
- -
-
Page/Page column 32-33
(2008/06/13)
-
- Cloning and functional characterisation of two regioselective flavonoid glucosyltransferases from Beta vulgaris
-
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
-
p. 1598 - 1612
(2008/02/12)
-
- Binding interaction of quercetin-3-β-galactoside and its synthetic derivatives with SARS-CoV 3CLpro: Structure-activity relationship studies reveal salient pharmacophore features
-
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
-
p. 8295 - 8306
(2007/10/03)
-
- Quercetin-4'-glucoside is more potent than quercetin-3-glucoside in protection of rat intestinal mucosa homogenates against iron ion-induced lipid peroxidation.
-
Quercetin is a typical antioxidative flavonoid found in vegetables, which is more commonly present as its glucosides, quercetin-3-glucoside (Q3G) and quercetin-4'-glucoside (Q4'G). The main aim of this study was to estimate the antioxidant activity of Q3G and Q4'G on iron ion-driven lipid peroxidation of the gastrointestinal mucosa. Q4'G markedly suppressed the lipid peroxidation when rat gastrointestinal mucosa homogenates were incubated with Fe(NO3)3 and ascorbic acid. Its effectiveness was greater as compared to that of Q3G and comparable to that of quercetin aglycone. Furthermore, Q4'G yielded higher amounts of quercetin aglycone than Q3G on incubation with the homogenates. However, Q4'G showed a lower chelating activity in comparison to Q3G. These results indicate that Q4'G, even though it has a low chelating activity, because of its efficient conversion to antioxidative aglycone on exposure to the mucosa, can act as a powerful antioxidant on iron ion driven lipid peroxidation in the intestinal mucosa. Thus, vegetables rich in Q4'G, such as onion, are likely to serve as favorable antioxidant sources for suppressing iron-induced oxidative stress in the intestinal tract.
- Murota, Kaeko,Mitsukuni, Yuki,Ichikawa, Mami,Tsushida, Tojiro,Miyamoto, Sayuri,Terao, Junji
-
p. 1907 - 1912
(2007/10/03)
-
- Recovery of isoquercetin from bioflavanoid pastes
-
The invention relates to a method for recovering high-purity isoquerectin from bioflavonoid pastes, that is from mother-liquor residues which are produced during the recovery of flavonoids, by extraction with a solvent mixture of methyl acetate and water.
- -
-
Page column 3-4
(2008/06/13)
-
- Synthesis and biological evaluation of flavonoids as vasorelaxant agents
-
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
-
p. 3949 - 3952
(2007/10/03)
-
- Regio- and stereoselective synthesis of the major metabolite of quercetin, quercetin-3-O-β-D-glucuronide
-
Protected quercetin was first transformed selectively in its 3-O-β-D-glucoside. Further protection of the remaining phenolic hydroxyl group allows a clean oxidation of the glucoside by TEMPO/NaOCl/NaBr under phase transfer conditions into the corresponding glucuronide which was cleanly deprotected to quercetin-3-O-β-D-glucuronide.
- Bouktaib, Mohamed,Atmani, Aziz,Rolando, Christian
-
p. 6263 - 6266
(2007/10/03)
-
- Phlomisflavosides A and B, new flavonol bisglycosides from Phlomis spinidens
-
From the aerial parts of Phlomis spinidens, two new flavonol bisglycosides, phlomisflavosides A (1) and B (2), were isolated together with the known compounds, astragalin, isoquercitrin, lamiridoside, phlomoside A, shanzhiside methyl ester, 8-O-acetylshanzhiside methyl ester, phlorigidoside C, rodioloside (=salidroside), forsythoside B, citroside A and lariciresinol-4′-O-β-D-glucoside. The structures of the new compounds were elucidated based on spectral and chemical evidence.
- Takeda, Yoshio,Isai, Natsuko,Masuda, Toshiya,Honda, Gisho,Takaishi, Yoshihisa,Ito, Michiho,Otsuka, Hideaki,Ashurmetov, Ozodbek A.,Khodzhimatov, Olimjon K.
-
p. 1039 - 1041
(2007/10/03)
-
- Isolation and antioxidant activity of galloyl flavonol glycosides from the seashore plant, Pemphis acidula.
-
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
-
p. 1302 - 1309
(2007/10/03)
-
- Glucosylation of Quercetin by a Cell Suspension Culture of Vitis sp.
-
A cell suspension culture of a Vitis hybrid converted quercetin to six glucosides.Their structures were identified as quercetin 3-O-β-D-glucopyranoside, quercetin 3,4'-di-O-β-D-glucopyranoside, quercetin 3,7-di-O-β-D-glucopyranoside, isorhamnetin 3-O-β-D-glucopyranoside, isorhamnetin 3,4'-di-O-β-D-glucopyranoside, and isorhamnetin 3,7-di-O-β-D-glucopyranoside by UV, FD-MS, 1H-NMR, 13C-NMR spectroscopy and TLC analysis.The course of conversion was also investigated and it was shown that quercetin 3-O-glucoside reached the maximum yield of 31 percent in 24 hr and then gradually disappeared accompanied by the production of quercetin 3,4'- and 3,7-di-O-glucosides.Although the same rise and fall relationship was observed between isorhamnetin 3-O-glucoside and isorhamnetin 3,4'- or 3,7-di-O-glucoside, their conversion ratios were much lower than those of quercetin glucosides.
- Kodama, Tohru,Ishida, Hidekatsu,Kokubo, Tetsuro,Yamakawa, Takashi,Noguchi, Hiroshi
-
p. 3283 - 3288
(2007/10/02)
-
- STRUCTURES AND ACCUMULATION PATTERNS OF SOLUBLE AND INSOLUBLE PHENOLICS FROM NORWAY SPRUCE NEEDLES
-
Key Word Index - Picea abies; Pinaceae; Norway spruce; phenolics; identification; seasonal accumulation pattern; turnover; translocation; cell wall localization; flavonol glucosyltransferase. - Abstract - Twenty-two soluble phenolics have been isolated from Norway spruce needles and their structures elucidated on the basis of chromatographic (TLC, HPLC), chemical (hydrolysis), enzymic and spectroscopic (UV, NMR, MS) techniques.These phenolics have been quantified by HPLC during the first year of needle development from a forest near Bad Muenstereifel (F.R.G.) and showed a differential accumulation pattern.Kaempferol 3-O-glucoside showed an interesting metabolism, indicating rapid turnover and/or translocation from a soluble to an insoluble (cell wall bound) pool.The enzyme involved in the formation of this flavonoid, UDP-glucose:flavonol glucosyltransferase, showed a marked transient increase in activity that correlated with the possible kaempferol 3-O-glucoside translocation.
- Strack, Dieter,Heilemann, Juergen,Wray, Victor,Dirks, Herbert
-
p. 2071 - 2078
(2007/10/02)
-
- STRUCTURAL ASPECTS OF ANTHOCYANIN-FLAVONOID COMPLEX FORMATION AND ITS ROLE IN PLANT COLOR
-
Key Word Index - Anthocyanin; flavonoid glycosides; synthesis; complex formation; plant color; spectral properties. The complex formation of flavonoids with anthocyanins, resulting in increase in both absorbance and in a bathochromic shift of the visible absorption maximum of the latter, is based mainly on hydrogen bond formation between the carbonyl group of the anthocyanin anhydrobase and aromatic hydroxyl groups of the complex-forming flavonoids.The larger the number of hydroxyl groups in the flavonoid molecule, the strongr the complex formation.The presence of a 3-hydroxyl group in the flavonoid molecule has little effect on the complex-forming ability.The nature of the sugar substituent of the complex-forming flavonoid compound has no influence on the reaction.The 5-hydroxyl group of flavonoids is strongly bound by intramolecular hydrogen bond to the 4-carbonyl and does not participate in the complex formation.The most important hydroxyl group in the flavonoid molecule is one in the 7-position.Unsaturation at C2-C3 in the heterocyclic ring is an important factor for complex formation.Aromatic hydroxyl groups in the flavonoid system alone cannot account for all the complex-forming ability, suggesting additional involvment by electrostatic forces and configurational or steric effects.
- Chen, Lao-Jer,Hrazdina, Geza
-
p. 297 - 304
(2007/10/02)
-
