- Phlomisflavosides A and B, new flavonol bisglycosides from Phlomis spinidens
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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.
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- STRUCTURES AND ACCUMULATION PATTERNS OF SOLUBLE AND INSOLUBLE PHENOLICS FROM NORWAY SPRUCE NEEDLES
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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
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- An Ambidextrous Polyphenol Glycosyltransferase PaGT2 from Phytolacca americana
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The glycosylation of small hydrophobic compounds is catalyzed by uridine diphosphate glycosyltransferases (UGTs). Because glycosylation is an invaluable tool for improving the stability and water solubility of hydrophobic compounds, UGTs have attracted attention for their application in the food, cosmetics, and pharmaceutical industries. However, the ability of UGTs to accept and glycosylate a wide range of substrates is not clearly understood due to the existence of a large number of UGTs. PaGT2, a UGT from Phytolacca americana, can regioselectively glycosylate piceatannol but has low activity toward other stilbenoids. To elucidate the substrate specificity and catalytic mechanism, we determined the crystal structures of PaGT2 with and without substrates and performed molecular docking studies. The structures have revealed key residues involved in substrate recognition and suggest the presence of a nonconserved catalytic residue (His81) in addition to the highly conserved catalytic histidine in UGTs (His18). The role of the identified residues in substrate recognition and catalysis is elucidated with the mutational assay. Additionally, the structure-guided mutation of Cys142 to other residues, Ala, Phe, and Gln, allows PaGT2 to glycosylate resveratrol with high regioselectivity, which is negligibly glycosylated by the wild-type enzyme. These results provide a basis for tailoring an efficient glycosyltransferase.
- Fukuda, Yohta,Hamada, Hiroki,Inoue, Tsuyoshi,Kawakami, Koki,Maharjan, Rakesh,Nakayama, Taisuke,Nakayama, Toru,Okimoto, Yuta,Ozaki, Shin-Ichi,Shimomura, Naomichi
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- Functional Characterization and Protein Engineering of a Triterpene 3-/6-/2′-O-Glycosyltransferase Reveal a Conserved Residue Critical for the Regiospecificity
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Engineering the function of triterpene glucosyltransferases (GTs) is challenging due to the large size of the sugar acceptors. In this work, we identified a multifunctional glycosyltransferase AmGT8 catalyzing triterpene 3-/6-/2′-O-glycosylation from the medicinal plant Astragalus membranaceus. To engineer its regiospecificity, a small mutant library was built based on semi-rational design. Variants A394F, A394D, and T131V were found to catalyze specific 6-O, 3-O, and 2′-O glycosylation, respectively. The origin of regioselectivity of AmGT8 and its A394F variant was studied by molecular dynamics and hydrogen deuterium exchange mass spectrometry. Residue 394 is highly conserved as A/G and is critical for the regiospecificity of the C- and O-GTs TcCGT1 and GuGT10/14. Finally, astragalosides III and IV were synthesized by mutants A394F, T131V and P192E. This work reports biocatalysts for saponin synthesis and gives new insights into protein engineering of regioselectivity in plant GTs.
- Bao, Yang-Oujie,Gao, Bai-Han,Li, Fu-Dong,Qiao, Xue,Shi, Xiao-Meng,Su, Hui-Fei,Wang, Hai-Dong,Ye, Min,Yi, Yang,Zhang, Meng
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supporting information
(2022/01/06)
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- 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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- Ep7GT, a glycosyltransferase with sugar donor flexibility from: Epimedium pseudowushanense, catalyzes the 7- O -glycosylation of baohuoside
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Icariin (1a), a 7-O-glycosylated flavonoid glycoside, is recognized as the major pharmacologically active ingredient of Epimedium plants, which have been used in traditional Chinese medicine for thousands of years. However, no glycosyltransferase (GT) responsible for the 7-O-glycosylation of flavonoids has been identified from Epimedium plants to date. Herein, a GT, Ep7GT, was identified from E. pseudowushanense B. L. Guo, which can regiospecifically transfer a glucose moiety to baohuoside (1) at 7-OH to form icariin (1a). Ep7GT showed a rare broad donor substrate spectrum, including UDP-glucose, UDP-xylose, UDP-N-acetylglucosamine, UDP-rhamnose, UDP-galactose, UDP-glucuronic acid and TDP-glucose. Moreover, two new derivatives of icariin (1a), 7-O-β-d-[2-(acetylamino)-2-deoxy-glucopyranosyl]-baohuoside (1b) and 7-O-β-d-xylosyl-baohuoside (1c), were biosynthesized by using Ep7GT in vitro. Engineered Escherichia coli harbouring Ep7GT was constructed, and 10.1 μg mL-1 icariin (1a) was yielded by whole-cell biotransformation with baohuoside (1) as the substrate. The present work not only characterizes the GT responsible for the 7-O-glycosylation in the biosynthesis of icariin in Epimedium plants, but also indicates the significant potential of an enzymatic approach for the production of glycosylated baohuoside derivatives with different sugar moieties. What's more, these findings also provide a promising alternative for producing natural/unnatural bioactive flavonoid glycosides by metabolic engineering.
- Feng, Keping,Chen, Ridao,Xie, Kebo,Chen, Dawei,Liu, Jimei,Du, Wenyu,Yang, Lin,Dai, Jungui
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p. 8106 - 8114
(2019/09/19)
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- Methylglucosylation of Phenolic Compounds by Fungal Glycosyltransferase-Methyltransferase Functional Modules
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Glycosylation endows both natural and synthetic small molecules with modulated physicochemical and biological properties. Plant and bacterial glycosyltransferases capable of decorating various privileged scaffolds have been extensively studied, but those from kingdom Fungi still remain underexploited. Here, we use a combination of genome mining and heterologous expression techniques to identify four novel glycosyltransferase-methyltransferase (GT-MT) functional modules from Hypocreales fungi. These GT-MT modules display decent substrate promiscuity and regiospecificity, methylglucosylating a panel of natural products such as flavonoids, stilbenoids, anthraquinones, and benzenediol lactones. Native GT-MT modules can be split up and regrouped into hybrid modules with similar or even improved efficacy as compared with native pairs. Methylglucosylation of kaempferol considerably improves its insecticidal activity against the larvae of oriental armyworm Mythimna separata (Walker). Our work provides a set of efficient biocatalysts for the combinatorial biosynthesis of small molecule glycosides that may have significant importance to the pharmaceutical, agricultural, and food industries.
- Xie, Linan,Zhang, Liwen,Bai, Jing,Yue, Qun,Zhang, Min,Li, Jiancheng,Wang, Chen,Xu, Yuquan
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p. 8573 - 8580
(2019/08/16)
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- Differentially evolved glucosyltransferases determine natural variation of rice flavone accumulation and UV-tolerance
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Decoration of phytochemicals contributes to the majority of metabolic diversity in nature, whereas how this process alters the biological functions of their precursor molecules remains to be investigated. Flavones, an important yet overlooked subclass of flavonoids, are most commonly conjugated with sugar moieties by UDP-dependent glycosyltransferases (UGTs). Here, we report that the natural variation of rice flavones is mainly determined by OsUGT706D1 (flavone 7-O-glucosyltransferase) and OsUGT707A2 (flavone 5-O-glucosyltransferase). UV-B exposure and transgenic evaluation demonstrate that their allelic variation contributes to UV-B tolerance in nature. Biochemical characterization of over 40 flavonoid UGTs reveals their differential evolution in angiosperms. These combined data provide biochemical insight and genetic regulation into flavone biosynthesis and additionally suggest that adoption of the positive alleles of these genes into breeding programs will likely represent a potential strategy aimed at producing stress-tolerant plants.
- Peng, Meng,Shahzad, Raheel,Gul, Ambreen,Subthain, Hizar,Shen, Shuangqian,Lei, Long,Zheng, Zhigang,Zhou, Junjie,Lu, Dandan,Wang, Shouchuang,Nishawy, Elsayed,Liu, Xianqing,Tohge, Takayuki,Fernie, Alisdair R.,Luo, Jie
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- Kaempferol and its glycosides from Equisetum silvaticum L. from the khanty-mansi autonomous area
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Three flavonoids were isolated from the aerial part of the wood horsetail (Equisetum silvaticum L.); two of them were found for the first time. The compounds were identified as kaempferol, kaempferol 3-O-β-D-galactopyranosyl-7-O-α-L-rhamnopyranoside and kaempferol 3-O-rutinosyl-7-O-L-rhamnopyranoside on the basis of the chemical transformations and IR, UV, 1H-NMR and mass spectra.
- Bonacheva,Botirov, E. Kh.
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p. 777 - 780
(2015/01/30)
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- Synthesis of flavonol 3-O-glycoside by UGT78D1
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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
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p. 425 - 432
(2012/11/13)
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- Study of kaempferol glycoside as an insulin mimic reveals glycon to be the key active structure
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Diabetes mellitus is increasing in prevalence with patient numbers rising throughout the world. Current treatments for diabetes mellitus focus on control of blood glucose levels. Certain kinds of flavonoids or their glycosides stimulate cells to improve glucose uptake and lower blood glucose levels. We synthesized kaempferol 3-O-neohesperidoside (1), a naturally occurring substance present in Cyathea phalerata Mart., reported to mimic the action of insulin. Synthetic 1 promoted glucose uptake in the cultured cell line, L6. Further studies to determine the core structure responsible for this activity using synthetic compounds revealed neohesperidose to be the primary pharmacophore. These findings support the use of certain saccharides as a potential novel treatment for diabetes mellitus by replacing or supporting insulin.
- Yamasaki, Kazuaki,Hishiki, Ryogo,Kato, Eisuke,Kawabata, Jun
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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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- NEW SYNERGISTIC PHYTOCHEMICAL COMPOSITION FOR THE TREATMENT OF OBESITY
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Synergistic anti-adipogenic and pro-lipolytic compositions for the prevention and amelioration of adipogenesis and lipolysis mediated diseases, comprising at least two extracts selected from enriched demethylated curcuminoids obtained from Curcuma longa, Moringa oleifera and Murraya koenigii. The anti-adipogenic and pro-lipolytic compositions optionally contain one or more anti-obesic agents. These compositions are useful for preventing anti-inflammatory and free radical mediated diseases.
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- Microbial metabolism of biologically active secondary metabolites from Nerium oleander L
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Ursolic acid (1) and kaempferol (3) are two major constituents of the Mediterranean plant Nerium oleander L. Microbial metabolism of (1) with Aspergillus flavus (ATCC 9170) resulted in the formation of 3-oxo-ursolic acid derivative, ursonic acid (2). On t
- Ibrahim, Amany,Khalifa, Sherief Ibrahim,Khafagi, Ishrak,Youssef, Diaa Tohamy,Khan, Shabana,Mesbah, Mostafa,Khan, Ikhlas
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experimental part
p. 1253 - 1258
(2009/10/02)
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- Synthesis of pelargonidin 3-O-6″-O-acetyl-β-d-glucopyranoside, an acylated anthocyanin, via the corresponding kaempferol glucoside
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The first total synthesis of pelargonidin 3-O-6″-O-acetyl-β-d-glucopyranoside, an acylated anthocyanin of magenta-colored Verbena flowers, was successfully carried out. The key intermediate, protected kaemferol 3-O-glucoside, was constructed by the Baker-
- Oyama, Kin-ichi,Kawaguchi, Satoshi,Yoshida, Kumi,Kondo, Tadao
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p. 6005 - 6009
(2008/02/10)
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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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- Isolation of camelliaside C from 'tea seed cake' and inhibitory effects of its derivatives on arachidonate 5-lipoxygenase
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A new flavonol glycoside, camelliaside C, was isolated from 'tea seed cake' prepared from the defatted seeds of Camellia sinensis O. KUNTZE. The structure was determined as kaempferol 3-O-β-D-galactopyranosyl-(1 → 2)- β-D-glucopyranoside by spectroscopic methods (FAB-MS, UV, IR, 1H- and 13C-NMR) and the enzymatic transformation of camelliaside C to astragalin. Camelliaside C showed an inhibitory effect on the arachidonate 5- lipoxygenase of RBL-1 cells (IC50: 1.4 x 10-4 M) as did camelliaside A and B isolated from the same product.
- Sekine,Arai,Ikegami,Fujii,Shindo,Yanagisawa,Ishida,Okonogi,Murakoshi
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p. 1185 - 1187
(2007/10/02)
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- An Acylated Kaempferol Glucoside Isolated from Quercus dentata as a Repellent against the Blue Mussel Mytilus edulis
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A new acylated kaemferol glucoside, kaempferol 3-O-(2",6"-di-O-(E)-p-coumaroyl-β-D-glucopyranoside), was isolated from the leaves of Quercus dentata Thumberg as a repellent against a fouling organism, the blue mussel Mytilus edulis L.
- Yamashita, Noriyuki,Etoh, Hideo,Sakata, Kanzo,Yagi, Akihito,Ina, Hiroji,Ina, Kazuo
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p. 1383 - 1386
(2007/10/02)
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- Constituents of Cupuliferae, 8. - A Novel, Highly Acylated Astragalin from Quercus ilex L.
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From leaves of Quercus ilex L. a new, highly acylated astragalin has been isolated and identified as 3-O-kaempferol 3,6-di-O-acetyl-2,4-di-O-(p-coumaroyl)-β-D-glucopyranoside (1).
- Romussi, Giovanni,Sancassan, Fernando,Parodi, Brunella,Bignardi, Gaetano
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p. 1864 - 1866
(2007/10/02)
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- Constituents of Cupuliferae, 9. - An Unusual Diester of Astragalin with cis- and trans-p-Coumaric Acid from Quercus ilex L.
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From leaves of Quercus ilex L. a new acylated astragalin has been isolated and identified as 3-O-kaempferol 2,6-di-O-(trans/cis-p-coumaroyl)-β-D-glucopyranoside (1).
- Romussi, Giovanni,Parodi, Brunella,Sancassan, Fernando
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p. 1867 - 1868
(2007/10/02)
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- Constituents of Cupuliferae, II. - A New Acylated Flavonoid Glycoside from Castanea sativa Mill.
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From leaves of Castanea sativa Mill. in addition to tiliroside , 3>, a new acylated flavonoid glycoside has been isolated and identified as kaempferol 3-O-Glc-(p-coumaroyl)-α-L-rhamnopyranosyl-(1->6)-β-D-glucopyranoside> (1).
- Romussi, Giovanni,Mosti, Luisa,Bignardi, Gaetano
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p. 761 - 764
(2007/10/02)
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- Structure Elucidation and Synthesis of Flavonol Acylglycosides. III. The Synthesis of Tiliroside
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Naturally occurring kaempferol 3-O-β-D-(6''-O-coumaroyl)glucopyranoside (tiliroside) has been synthesized thereby confirming its structure.This is the first acylated flavonoid glycoside to be synthesized.
- Vermes, Barbara,Chari, Vedanta Mohan,Wagner, Hildebert
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p. 1964 - 1968
(2007/10/02)
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- O-ACYLATED FLAVONOID GLYCOSIDES FROM THE NEEDLES OF Picea obovata II. 3''- and 6''-ISOMERS OF p-COUMAROYLASTRAGALIN
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Two monoacylated glycosides have been isolated from the needles of Picea obovata - the previously unknown 3''-p-coumaroylastragalin (I) and 6''-p-coumaroylastragalin (II).It has been established that under the conditions of mild saponification and acid hydrolysis isomerization of (I) into (II) and the splitting out of the acid residue takes place.The position of the acyl substituent has been shown by PMR spectroscopy using the INDOR method.The physicochemical characteristics of the acylated glycosides and of their heptaacetates are given.
- Zapesochnaya, G. G.,Ivanova, S. Z.,Sheichenko, V. I.,Tyukavkina, N. A.,Medvedeva, S. A.
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p. 141 - 145
(2007/10/02)
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