Articoli di riviste: "C-glycosyl compound"

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Nayak, Riddhi A., e Anvita D. Mangte. "Synthesis and Antimicrobial Studies of Novel N-Glycosyl Hydrazino Carbothioamide". Asian Journal of Chemistry 33, n. 1 (2020): 127–31. http://dx.doi.org/10.14233/ajchem.2021.22967.

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In view of applications of N-glycosylated compounds in medicinal chemistry and in many other ways, herein the synthesis of novel N-glycosyl hydrazino carbothioamides is reported. New N-glycosyl hydrazino carbothioamides were synthesized by the condensation of per-O-acetyl glycosyl isothiocyanate with different aromatic hydrazides. The newly synthesized compounds were characterized by using the IR, 1H NMR and mass spectral studies. Antimicrobial evaluation of the synthesized N-glycosyl hydrazino carbothioamide was also examined. Antimicrobial activities of the synthesized compound were evaluated against bacteria E. coli, P. aeruginosa, S. aureus, S. pyogenus and fungi C. albicans, A. niger and A. clavatus. All the N-glycosyl hydrazino carbothioamides exhibit promising antimicrobial activity.

2

Zhang, Tao, e Zhijie Fang. "The concise synthesis and biological evaluation of C-glycosyl chalcone analogues inspired by the natural product aspalathin". RSC Advances 7, n. 5 (2017): 3021–24. http://dx.doi.org/10.1039/c6ra26969a.

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We described the synthesis and biological evaluation of C-glycosyl chalcone analogues of aspalathin. Results indicate that compound 3c′ is supposed to be the most promising compound with good antioxidant and anticancer abilities.

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Cid-Pérez, Teresa Soledad, Guadalupe Virginia Nevárez-Moorillón, Carlos Enrique Ochoa-Velasco, Addí Rhode Navarro-Cruz, Paola Hernández-Carranza e Raúl Avila-Sosa. "The Relation between Drying Conditions and the Development of Volatile Compounds in Saffron (Crocus sativus)". Molecules 26, n. 22 (18 novembre 2021): 6954. http://dx.doi.org/10.3390/molecules26226954.

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Saffron is derived from the stigmas of the flower Crocus sativus L. The drying process is the most important post-harvest step for converting C. sativus stigmas into saffron. The aim of this review is to evaluate saffron’s post-harvest conditions in the development of volatile compounds and its aroma descriptors. It describes saffron’s compound generation by enzymatic pathways and degradation reactions. Saffron quality is described by their metabolite’s solubility and the determination of picrocrocin, crocins, and safranal. The drying process induce various modifications in terms of color, flavor and aroma, which take place in the spice. It affects the aromatic species chemical profile. In the food industry, saffron is employed for its sensory attributes, such as coloring, related mainly to crocins (mono-glycosyl esters or di-glycosyl polyene).

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Scordino, Monica, Leonardo Sabatino, Adalgisa Belligno e Giacomo Gagliano. "Characterization of Polyphenolic Compounds in Unripe Chinotto (Citrus myrtifolia) Fruit by HPLC/PDA/ESI/MS-MS". Natural Product Communications 6, n. 12 (dicembre 2011): 1934578X1100601. http://dx.doi.org/10.1177/1934578x1100601218.

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The flavonoid and furocoumarin composition was investigated of peel and pulp tissues of unripe fruits of Citrus myrtifolia Rafinesque, an ingredient of the popular soft drink “chinotto”. Compound separation and identification was made using an HPLC-PDA detector coupled to ESI/MS/MS in positive and negative mode. Eighteen compounds (3-hydroxy-3-methylglutaryl-, C- and O-glycosyl flavonoids, furocoumarins and polymethoxylated flavones) were identified and quantified. Data indicated that the overall amount of flavonoids and furocoumarins in peel was higher than in the pulp, even though their relative distribution did not significantly change, apart from a different distribution of flavones and a lower content of naringin in the peel.

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Bokor, Éva, Attila Ferenczi, Mahir Hashimov, Éva Juhász-Tóth, Zsófia Götz, Alshimaa Ibrahim Zaki e László Somsák. "First Synthesis of 3-Glycopyranosyl-1,2,4-Triazines and Some Cycloadditions Thereof". Molecules 27, n. 22 (12 novembre 2022): 7801. http://dx.doi.org/10.3390/molecules27227801.

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C-glycopyranosyl derivatives of six-membered heterocycles are scarcely represented in the chemical literature and the title 3-glycopyranosyl-1,2,4-triazines are completely unknown. In this paper, the first synthesis of this compound class is accomplished by the cyclocondensation of C-glycosyl formamidrazones and 1,2-dicarbonyl derivatives. In addition, the synthesis of C-glycopyranosyl 1,2,4-triazin-5(4H)-ones was also carried out by the transformation of the above formamidrazones with α-keto-carboxylic esters. Inverse electron demand Diels–Alder reactions of 3-glycopyranosyl-1,2,4-triazines with a bicyclononyne derivative yielded the corresponding annulated 2-glycopyranosyl pyridines.

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Driskill, Lance E., Kevin Kusy, Michael W. Bauer e Robert M. Kelly. "Relationship between Glycosyl Hydrolase Inventory and Growth Physiology of the Hyperthermophile Pyrococcus furiosus on Carbohydrate-Based Media". Applied and Environmental Microbiology 65, n. 3 (1 marzo 1999): 893–97. http://dx.doi.org/10.1128/aem.65.3.893-897.1999.

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ABSTRACT Utilization of a range of carbohydrates for growth by the hyperthermophile Pyrococcus furiosus was investigated by examining the spectrum of glycosyl hydrolases produced by this microorganism and the thermal labilities of various saccharides. Previously, P. furiosus had been found to grow in batch cultures on several α-linked carbohydrates and cellobiose but not on glucose or other β-linked sugars. Although P. furiosuswas not able to grow on any nonglucan carbohydrate or any form of cellulose in this study (growth on oat spelt arabinoxylan was attributed to glucan contamination of this substrate), significant growth at 98°C occurred on β-1,3- and β-1,3–β-1,4-linked glucans. Oligosaccharides generated by digestion with a recombinant laminarinase derived from P. furiosus were the compounds that were most effective in stimulating growth of the microorganism. In several cases, periodic addition of β-glucan substrates to fed-batch cultures limited adverse thermochemical modifications of the carbohydrates (i.e., Maillard reactions and caramelization) and led to significant increases (as much as two- to threefold) in the cell yields. While glucose had only a marginally positive effect on growth in batch culture, the final cell densities nearly tripled when glucose was added by the fed-batch procedure. Nonenzymatic browning reactions were found to be significant at 98°C for saccharides with degrees of polymerization (DP) ranging from 1 to 6; glucose was the most labile compound on a mass basis and the least labile compound on a molar basis. This suggests that for DP of 2 or greater protection of the nonreducing monosaccharide component may be a factor in substrate availability. For P. furiosus, carbohydrate utilization patterns were found to reflect the distribution of the glycosyl hydrolases which are known to be produced by this microorganism.

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Drandarov, Konstantin, e Willi Kantlehner. "Orthoamides and Iminium Salts, LXXX [1]. C-Glycosyl Alkynecarboxylic Acid Orthoamides. Versatile Intermediates in the Synthesis of New Types of Highly Substituted C-Nucleoside Analogs". Zeitschrift für Naturforschung B 67, n. 7 (1 luglio 2012): 699–716. http://dx.doi.org/10.5560/znb.2012-0108.

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The C-glycosyl alkynecarboxylic acid orthoamides 22 and 23 are proposed as versatile precursors for the synthesis of new types of C-nucleoside analogs. The new synthetic strategy includes alkynylation of protected aldoses 13 or ketoses by Grignard ethynylation or Barbier propargylation, O-protection of the resulting alkynols 14-16, and nucleophilic addition of the metalated protected terminal alkynes 20 and 21 to peralkylguanidinium salt 2 to afford the corresponding alkynecarboxylic acid orthoamides 22 and 23, which in reactions with mono or bis-nucleophiles could serve as building blocks for the construction of a wide variety of C-nucleoside-like binary conjugates. All the steps are demonstrated on 2,4,3,5-bis(4-methoxybenzylidene)-protected L-xylose 11 as a model compound. The synthesis of a representative series of C-glycosidic conjugates of highly substituted “push-pull” 1,3-butadienes 32-35, pyrimidines 24-31, and 2-pyridones 36-39 is included. The stereochemistry of all described compounds is established by 2D-NMR techniques. A general character of the proposed synthetic strategy, when applied to different appropriately protected sugar derivatives, is suggested, and a biomedical applicability of the described type of conjugates is expected.

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Muller, Christo J. F., Elizabeth Joubert, Nireshni Chellan, Yutaka Miura e Kazumi Yagasaki. "New Insights into the Efficacy of Aspalathin and Other Related Phytochemicals in Type 2 Diabetes—A Review". International Journal of Molecular Sciences 23, n. 1 (29 dicembre 2021): 356. http://dx.doi.org/10.3390/ijms23010356.

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In the pursuit of bioactive phytochemicals as a therapeutic strategy to manage metabolic risk factors for type 2 diabetes (T2D), aspalathin, C-glucosyl dihydrochalcone from rooibos (Aspalathus linearis), has received much attention, along with its C-glucosyl flavone derivatives and phlorizin, the apple O-glucosyl dihydrochalcone well-known for its antidiabetic properties. We provided context for dietary exposure by highlighting dietary sources, compound stability during processing, bioavailability and microbial biotransformation. The review covered the role of these compounds in attenuating insulin resistance and enhancing glucose metabolism, alleviating gut dysbiosis and associated oxidative stress and inflammation, and hyperuricemia associated with T2D, focusing largely on the literature of the past 5 years. A key focus of this review was on emerging targets in the management of T2D, as highlighted in the recent literature, including enhancing of the insulin receptor and insulin receptor substrate 1 signaling via protein tyrosine phosphatase inhibition, increasing glycolysis with suppression of gluconeogenesis by sirtuin modulation, and reducing renal glucose reabsorption via sodium-glucose co-transporter 2. We conclude that biotransformation in the gut is most likely responsible for enhancing therapeutic effects observed for the C-glycosyl parent compounds, including aspalathin, and that these compounds and their derivatives have the potential to regulate multiple factors associated with the development and progression of T2D.

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Kandziora, Maja, e Hans-Ulrich Reissig. "Synthesis of rigid p-terphenyl-linked carbohydrate mimetics". Beilstein Journal of Organic Chemistry 10 (30 luglio 2014): 1749–58. http://dx.doi.org/10.3762/bjoc.10.182.

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An approach to β-D-2-aminotalose- and β-D-2-aminoidose-configured carbohydrate mimetics bearing a phenyl substituent is described. Unnatural divalent rigid p-terphenyl-linked C-aryl glycosides with 2.0 nm dimension are available using Suzuki cross-couplings. The key compound, a p-bromophenyl-substituted 1,2-oxazine, was prepared by a stereoselective [3 + 3]-cyclization of a D-isoascorbic acid-derived (Z)-nitrone and lithiated TMSE-allene. The Lewis acid-induced rearrangement of this heterocycle provided the corresponding bicyclic 1,2-oxazine derivative that may be regarded as internally protected amino sugar analogue. After subsequent reduction of the carbonyl group, the resulting bicyclic compound was used for Suzuki cross-couplings to form biphenyl aminopyran or p-terphenyl-linked dimers. Hydrogenolysis afforded new unnatural aminosugar mimetics. Zinc in the presence of acid or samarium diiodide were examined for the N–O bond cleavage in order to obtain the rigid p-terphenyl-linked C-glycosyl dimers.

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El-Sayed, Wael A., Fahad M. Alminderej, Marwa M. Mounier, Eman S. Nossier, Sayed M. Saleh e Asmaa F. Kassem. "New 1,2,3-Triazole-Coumarin-Glycoside Hybrids and Their 1,2,4-Triazolyl Thioglycoside Analogs Targeting Mitochondria Apoptotic Pathway: Synthesis, Anticancer Activity and Docking Simulation". Molecules 27, n. 17 (3 settembre 2022): 5688. http://dx.doi.org/10.3390/molecules27175688.

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Toxicity and resistance to newly synthesized anticancer drugs represent a challenging phenomenon of intensified concern arising from variation in drug targets and consequently the prevalence of the latter concern requires further research. The current research reports the design, synthesis, and anticancer activity of new 1,2,3-triazole-coumarin-glycosyl hybrids and their 1,2,4-triazole thioglycosides as well as acyclic analogs. The cytotoxic activity of the synthesized products was studied against a panel of human cancer cell lines. Compounds 8, 10, 16 and 21 resulted in higher activities against different human cancer cells. The impact of the hybrid derivative 10 upon different apoptotic protein markers, including cytochrome c, Bcl-2, Bax, and caspase-7 along with its effect on the cell cycle was investigated. It revealed a mitochondria-apoptotic effect on MCF-7 cells and had the ability to upregulate pro-apoptotic Bax protein and downregulate anti-apoptotic Bcl-2 protein and thus implies the apoptotic fate of the cells. Furthermore, the inhibitory activities against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases for 8, 10 and 21 were studied to detect the mechanism of their high potency. The coumarin-triazole-glycosyl hybrids 8 and 10 illustrated excellent broad inhibitory activity (IC50= 0.22 ± 0.01, 0.93 ± 0.42 and 0.24 ± 0.20 μM, respectively, for compound 8), (IC50 = 0.12 ± 0.50, 0.79 ± 0.14 and 0.15± 0. 60 μM, respectively, for compound 10), in comparison with the reference drugs, erlotinib, sorafenib and roscovitine (IC50 = 0.18 ± 0.05, 1.58 ± 0.11 and 0.46 ± 0.30 μM, respectively). In addition, the docking study was simulated to afford better rationalization and put insight into the binding affinity between the promising derivatives and their targeted enzymes and that might be used as an optimum lead for further modification in the anticancer field.

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Küpeli, Esra, Mustafa Aslan, İlhan Gürbüz e Erdem Yesilada. "Evaluation of in vivo Biological Activity Profile of Isoorientin". Zeitschrift für Naturforschung C 59, n. 11-12 (1 dicembre 2004): 787–90. http://dx.doi.org/10.1515/znc-2004-11-1204.

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Anti-nociceptive, anti-inflammatory and gastroprotective activities of the known C-glycosyl flavonoid, isoorientin, were studied in rats and mice. For the anti-nociceptive activity assessment the p-benzoquinone-induced writing test, for the anti-inflammatory activity the carrageenan-induced hind paw edema model in mice, and for the gastroprotective activity the EtOH-induced ulcerogenesis model in rats were used. Isoorientin was shown to possess significant anti-nociceptive and anti-inflammatory activities at 15 mg/kg and 30 mg/kg doses, without inducing any apparent acute toxicity as well as gastric damage. However, the compound did not possess any significant gastroprotective activity against EtOH-induced ulcerogenesis.

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Francioso, Antonio, Katrin Franke, Claudio Villani, Luciana Mosca, Maria D’Erme, Stefan Frischbutter, Wolfgang Brandt, Angel Sanchez-Lamar e Ludger Wessjohann. "Insights into the Phytochemistry of the Cuban Endemic Medicinal Plant Phyllanthus orbicularis: Fideloside, a Novel Bioactive 8-C-glycosyl 2,3-Dihydroflavonol". Molecules 24, n. 15 (6 agosto 2019): 2855. http://dx.doi.org/10.3390/molecules24152855.

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Phyllanthus orbicularis (Phyllanthaceae) is an endemic evergreen tropical plant of Cuba that grows in the western part of the island and is used in traditional medicine as an infusion. The aqueous extract of this plant presents a wide range of pharmacological activitiessuch as antimutagenic, antioxidant and antiviral effects. Given the many beneficial effects and the great interest in the development of new pharmacological products from natural sources, the aim of this work was to investigate the phytochemistry of this species and to elucidate the structure of the main bioactive principles. Besides the presence of several known polyphenols, the major constituent was hitherto not described. The chemical structure of this compound, here named Fideloside, was elucidated by means of HR-ESIMS/MSn, 1D/2D NMR, FT-IR, and ECD as (2R,3R)-(−)-3’,4′,5,7-tetrahydroxydihydroflavonol-8-C-β-D-glucopyranoside. The compound, as well as the plant aqueous preparations, showed promising bioactive properties, i.e., anti-inflammatory capacity in human explanted monocytes, corroborating future pharmacological use for this new natural C-glycosyl flavanonol.

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Auzanneau, France-Isabelle, e David R. Bundle. "Application of thioglycoside chemistry to the synthesis of trisaccharides and deoxy-trisaccharides related to the Shigella flexneri Y polysaccharide". Canadian Journal of Chemistry 71, n. 4 (1 aprile 1993): 534–48. http://dx.doi.org/10.1139/v93-076.

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The Shigella flexneri lipopolysaccharide has a biological repeating unit, → 2)α-L-Rhap(1→2)α-L-Rhap(1→3)α-L-Rhap(1→3)β-D-GlcNAcp(1 → ABCD, but the residue segment BCD suffices to fill the binding site of an O-antigen specific monoclonal antibody, SYA/J6. Synthetic modifications to this trisaccharide have been designed to investigate the involvement in binding of the acetamido moiety, the 4- and 6-OH groups of the GlcNAc residue D, the 4′-OH group of the Rha residue C, and the 3″- and 4″-OH groups of the Rha residue B. Sequential chain extension provided the protected trisaccharides 18, 24, 26, 28, 30, 32, and 35 using thioglycoside glycosyl donors activated by iodonium ions generated in situ from N-iodosuccinimide and triflic acid. Trisaccharides each monodeoxygenated in either ring B 25 and 27 or ring C 29 were accessed by the use of 3,6-dideoxy or 4,6-dideoxy glycosyl donors 14 and 17 and when these were used in sequential steps trisaccharides 31 and 33, each deoxygenated at double sites in adjacent residues, were obtained. Selective protection of the glucosamine residue as its N-benzyloxycarbonyl derivative provided a facile route to the trisaccharide amino compound 20, from which N-acetyl 21, N-propionyl 22, and N-trifluoroacetyl 23 derivatives were directly prepared. Orthoester intermediates were detected in several glycosylation reactions and culminated in an orthoacetate 34 as a major product rather than the target trisaccharide 35. When triflic acid concentration was increased these products were avoided but acid-catalyzed migration of a 2-O-acetyl group led to both 1→2 and 1→3 linked trisaccharides 35 and 37. To avoid similar undesirable 1,2-linked products, a block synthetic strategy using the 2-O-benzoylated disaccharide glycosyl donor 40 was chosen so that the propensity for orthoester formation was minimized in reactions leading to the trisaccharide analogue deoxygenated at C-6 of the glucosamine unit D.

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Szennyes, Eszter, Gyöngyi Gyémánt, László Somsák e Éva Bokor. "Synthesis of New Series of 2-C-(β-D-glucopyranosyl)-Pyrimidines and Their Evaluation as Inhibitors of Some Glycoenzymes". Molecules 25, n. 3 (6 febbraio 2020): 701. http://dx.doi.org/10.3390/molecules25030701.

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Despite the substantial interest in C-glycosyl heterocycles as mimetics of biologically active native glycans, the appearance of C-glycopyranosyl derivatives of six-membered heterocycles, both in synthetic and biological contexts, is rather scarce. As part of our ongoing research program aimed at preparing hitherto barely known 2-C-glycopyranosyl pyrimidines, the goal of the present study was to synthesize new 5-mono- and multiply substituted derivatives of this compound class. Thus, 2-C-(β-D-glucopyranosyl)-5,6-disubstituted-pyrimidin-4(3H)-ones and 4-amino-2-C-(β-D-glucopyranosyl)-5,6-disubstituted-pyrimidines were prepared by base-mediated cyclocondensations of O-perbenzylated and O-unprotected C-(β-D-glucopyranosyl) formamidine hydrochlorides with methylenemalonic acid derivatives. The 2-C-(β-D-glucopyranosyl)-5-substituted-pyrimidines were obtained from the same amidine precursors upon treatment with vinamidinium salts. The deprotected derivatives of these pyrimidines were tested as inhibitors of some glycoenzymes. None of them showed inhibitory activity towards glycogen phosphorylase and α- and β-glucosidase enzymes, but some members of the sets exhibited moderate inhibition against bovine liver β-galactosidase.

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Zarev, Yancho, Pavlinka Popova, Kenn Foubert, Sandra Apers, Arnold Vlietinck, Luc Pieters e Iliana Ionkova. "Biotransformation to Produce the Anticancer Compound Colchicoside Using Cell Suspension Cultures of Astragalus vesicarius Plant Species". Natural Product Communications 14, n. 1 (gennaio 2019): 1934578X1901400. http://dx.doi.org/10.1177/1934578x1901400108.

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This paper discusses the biotechnological process affected by means of plant suspension cultures, for production of colchicoside, the 3- O-glucosyl derivative of 3- O-demethylcolchicine. Colchicoside can be considered as an antitumoural prodrug which is activated after oral administration and may have more beneficial effects and a better toxicity profile (because of a slow-release effect) than colchicine. We have developed a green and efficient biotechnological method using colchicine, as a precursor, derived from its natural source G. superba seeds. Plant suspension cultures of Astragalus vesicarius were used to design a practical biotechnological platform to replace a methyl group at C-3 regiospecifically by a glycosyl moiety in colchicine. Using different concentrations of a colchicine-rich extract, the maximum enzymatic potential of Astragalus vesicarius suspension cells was achieved. According to quantitative HPLC-UV analysis, levels of 9.35 μmol/g DW colchicoside were achieved. This is the first report of region-specific glycosylation at C-3 of the aromatic ring A of the colchicine using plant suspension cultures.

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Kumazawa, Toshihiro, Takayuki Kimura, Shigeru Matsuba, Shingo Sato e Jun-ichi Onodera. "Cleavage of the C–C linkage between the sugar and the aglycon in C-glycosylphloroacetophenone, and the NMR spectral characteristics of the resulting di-C-glycosyl compound". Carbohydrate Research 334, n. 3 (agosto 2001): 207–13. http://dx.doi.org/10.1016/s0008-6215(01)00183-5.

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Lin, Zikai, Xiaowei Zhou, Chen Yuan, Yan Fang, Haozheng Zhou, Zhenhua Wang, Jun Dang e Gang Li. "Impact of Preparative Isolation of C-Glycosylflavones Derived from Dianthus superbus on In Vitro Glucose Metabolism". Molecules 29, n. 2 (9 gennaio 2024): 339. http://dx.doi.org/10.3390/molecules29020339.

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Dianthus superbus L. has been extensively studied for its potential medicinal properties in traditional Chinese medicine and is often consumed as a tea by traditional folk. It has the potential to be exploited in the treatment of inflammation, immunological disorders, and diabetic nephropathy. Based on previous studies, this study continued the separation of another subfraction of Dianthus superbus and established reversed-phase/reversed-phase and reversed-phase/hydrophilic (RPLC) two-dimensional (2D) high-performance liquid chromatography (HPLC) modes, quickly separating two C-glycosylflavones, among which 2″-O-rhamnosyllutonarin was a new compound and isomer with 6‴-O-rhamnosyllutonarin. This is the first study to investigate the effects of 2″-O-rhamnosyllutonarin and 6‴-O-rhamnosyllutonarin on cellular glucose metabolism in vitro. First, molecular docking was used to examine the effects of 2″-O-rhamnosyllutonarin and 6″-O-rhamnosyllutonarin on AKT and AMPK; these two compounds exhibited relatively high activity. Following this, based on the HepG2 cell model of insulin resistance, it was proved that both of the 2″-O-rhamnosyllutonarin and 6‴-O-rhamnosyllutonarin demonstrated substantial efficacy in ameliorating insulin resistance and were found to be non-toxic. Simultaneously, it is expected that the methods developed in this study will provide a basis for future studies concerning the separation and pharmacological effects of C-glycosyl flavonoids.

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Zanatta, Ana C., Natália Carolina Vieira, Renato Dantas-Medeiros, Wagner Vilegas e RuAngelie Edrada-Ebel. "Understanding the Seasonal Effect of Metabolite Production in Terminalia catappa L. Leaves through a Concatenated MS- and NMR-Based Metabolomics Approach". Metabolites 13, n. 3 (27 febbraio 2023): 349. http://dx.doi.org/10.3390/metabo13030349.

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Terminalia catappa L. (Combretaceae) is a medicinal plant that is part of the Brazilian biodiversity; this plant is popularly used for the treatment of a wide range of diseases. To better understand the chemical composition of T. catappa in different seasons, we conducted a thorough study using LC-MS and NMR data analysis techniques. The study helped obtain a chemical profile of the plant ethanolic extracts in different seasons of the year (spring, summer, autumn, and winter). The dereplication of LC-HRMS data allowed the annotation of 90 compounds in the extracts of T. catappa (hydrolyzable tannins, ellagic acid derivatives, and glycosylated flavonoids). Triterpenes and C-glycosyl flavones were the compounds that significantly contributed to differences observed between T. catappa plant samples harvested in autumn/winter and spring, respectively. The variations observed in the compound composition of the plant leaves may be related to processes induced by environmental stress and leaf development. Data fusion applied in the metabolomic profiling study allowed us to identify metabolites with greater confidence, and provided a better understanding regarding the production of specialized metabolites in T. catappa leaves under different environmental conditions, which may be useful to establish appropriate quality criteria for the standardization of this medicinal plant.

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Zhong, Jianshu, Peiyao Lu, Hanjing Wu, Ziyao Liu, Javad Sharifi-Rad, William N. Setzer e Hafiz A. R. Suleria. "Current Insights into Phytochemistry, Nutritional, and Pharmacological Properties of Prosopis Plants". Evidence-Based Complementary and Alternative Medicine 2022 (11 marzo 2022): 1–18. http://dx.doi.org/10.1155/2022/2218029.

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Prosopis is a regional cash crop that is widely grown in arid, semiarid, tropical, and subtropical areas. Compared with other legume plants, Prosopis is underutilized and has great potentialities. Prosopis not only is a good source of timber, construction, fencing material, and gum, but also can be applied for food, beverage, feed, and medicine. Prosopis contains numerous phytochemical constituents, including carbohydrates, proteins, fatty acids, minerals, and vitamins, while varieties of phenolic compounds have also been identified from different parts of Prosopis. Flavonoids (especially C-glycosyl flavonoids), tannins, catechin, 4′-O-methyl-gallocatechin, mesquitol, and quercetin O-glycosides are significant phenolic contents in Prosopis. Various extracts of Prosopis displayed a wide range of biological properties, such as antioxidant, antihyperglycemic, antibacterial, anthelmintic, antitumor, and anticancer. Additionally, Prosopis has the potential to be an ideal diet that contains abundant dietary fiber, minerals, galactomannans, and low-fat content. However, the bioactivity and pharmacological properties associated with Prosopis were influenced by the bioavailability of phytochemicals, various antinutritional compounds, and the interactions of protein and phenolic compounds. The bioavailability of Prosopis is mainly affected by phenolic contents, especially catechin. The antinutritional compounds negatively affect the nutritional qualities of Prosopis, which can be prevented by heating. The protein-phenolic compound interactions can help the human body to absorb quercetin from Prosopis. This literature review aimed to provide systematic information on the physical, biochemical, pharmacological, and nutritional properties and potential applications of Prosopis.

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Gai, Francesco, Michał A. Janiak, Katarzyna Sulewska, Pier Giorgio Peiretti e Magdalena Karamać. "Phenolic Compound Profile and Antioxidant Capacity of Flax (Linum usitatissimum L.) Harvested at Different Growth Stages". Molecules 28, n. 4 (14 febbraio 2023): 1807. http://dx.doi.org/10.3390/molecules28041807.

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The profile of phenolic compounds changes during the growth of a plant and this change affects its antioxidant potential. The aim of this research has been to find the growth stage of flax with the highest antioxidant capacity, and to determine the phenolic compounds responsible for such a capacity. Flax was harvested in six growth stages: from stem extension to mature seeds. The phenolic compounds were identified using LC–TOF–MS and quantified in an extract and in the fresh matter (FM) of each growth stage. The radical scavenging activity against ABTS•+ and DPPH•, the ferric-reducing antioxidant power (FRAP), and the antioxidant activity in the β-carotene-linoleic acid emulsion system were determined. Mono- and di-C-glycosyl flavones were found to be the most abundant phenolics of the aerial parts of flax, which also showed the highest content of isoorientin (210–538 µg/g FM). Coniferin, its derivative, and hydroxycinnamic acid derivatives were also detected. The plant was richer in flavone C-glycosides from stem extension to seed ripening (1105–1413 µg/g FM) than at the mature seed stage (557 µg/g FM). Most of the individual flavone C-glycoside contents in the extracts decreased when increasingly older plants were considered; however, the isoorientin content did not change significantly from the steam extension to the seed ripening stages. The antiradical activity against ABTS•+ and FRAP was higher for the aerial parts of the flax harvested at the flowering, brown capsule, and seed ripening stages, mainly due to the presence of flavone C-glycosides. The oxidation of β-carotene-linoleic acid emulsion was instead inhibited more effectively by the extracts from plants at the brown capsule and mature seed stages. Coniferin and its derivative were significantly involved in this activity. The extracts from the aerial parts of the flax harvested from flowering to seed ripening could be a valuable source of flavone C-glycosides for use as nutraceuticals and components of functional foods.

21

Zhou, Heyang, Niao Yang, Wei Li, Xuemi Peng, Jiaxiao Dong, Yuanying Jiang, Lan Yan, Dazhi Zhang e Yongsheng Jin. "Exploration of Baicalein-Core Derivatives as Potent Antifungal Agents: SAR and Mechanism Insights". Molecules 28, n. 17 (30 agosto 2023): 6340. http://dx.doi.org/10.3390/molecules28176340.

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Baicalein (BE), the major component of Scutellaria Baicalensis, exhibited potently antifungal activity against drug-resistant Candida albicans, and strong inhibition on biofilm formation. Therefore, a series of baicalein-core derivatives were designed and synthesized to find more potent compounds and investigate structure–activity relationship (SAR) and mode of action (MoA). Results demonstrate that A4 and B5 exert a more potent antifungal effect (MIC80 = 0.125 μg/mL) than BE (MIC80 = 4 μg/mL) when used in combination with fluconazole (FLC), while the MIC80 of FLC dropped from 128 μg/mL to 1 μg/mL. SAR analysis indicates that the presence of 5-OH is crucial for synergistic antifungal activities, while o-dihydroxyls and vic-trihydroxyls are an essential pharmacophore, whether they are located on the A ring or the B ring of flavonoids. The MoA demonstrated that these compounds exhibited potent antifungal effects by inhibiting hypha formation of C. albicans. However, sterol composition assay and enzymatic assay conducted in vitro indicated minimal impact of these compounds on sterol biosynthesis and Eno1. These findings were further confirmed by the results of the in-silico assay, which assessed the stability of the complexes. Moreover, the inhibition of hypha of this kind of compound could be attributed to their effect on the catalytic subunit of 1,3-β-d-glucan synthase, 1,3-β-d-glucan-UDP glucosyltransferase and glycosyl-phosphatidylinositol protein, rather than inhibiting ergosterol biosynthesis and Eno1 activity by Induced-Fit Docking and Molecular Dynamics Simulations. This study presents potential antifungal agents with synergistic effects that can effectively inhibit hypha formation. It also provides new insights into the MoA.

22

Pérez-Mendoza, Daniel, Miguel Ángel Rodríguez-Carvajal, Lorena Romero-Jiménez, Gabriela de Araujo Farias, Javier Lloret, María Trinidad Gallegos e Juan Sanjuán. "Novel mixed-linkage β-glucan activated by c-di-GMP inSinorhizobium meliloti". Proceedings of the National Academy of Sciences 112, n. 7 (3 febbraio 2015): E757—E765. http://dx.doi.org/10.1073/pnas.1421748112.

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An artificial increase of cyclic diguanylate (c-di-GMP) levels inSinorhizobium meliloti8530, a bacterium that does not carry known cellulose synthesis genes, leads to overproduction of a substance that binds the dyes Congo red and calcofluor. Sugar composition and methylation analyses and NMR studies identified this compound as a linear mixed-linkage (1→3)(1→4)-β-d-glucan (ML β-glucan), not previously described in bacteria but resembling ML β-glucans found in plants and lichens. This unique polymer is hydrolyzed by the specific endoglucanase lichenase, but, unlike lichenan and barley glucan, it generates a disaccharidic →4)-β-d-Glcp-(1→3)-β-d-Glcp-(1→ repeating unit. A two-gene operonbgsBArequired for production of this ML β-glucan is conserved among several genera within the order Rhizobiales, wherebgsAencodes a glycosyl transferase with domain resemblance and phylogenetic relationship to curdlan synthases and to bacterial cellulose synthases. ML β-glucan synthesis is subjected to both transcriptional and posttranslational regulation.bgsBAtranscription is dependent on the exopolysaccharide/quorum sensing ExpR/SinI regulatory system, and posttranslational regulation seems to involve allosteric activation of the ML β-glucan synthase BgsA by c-di-GMP binding to its C-terminal domain. To our knowledge, this is the first report on a linear mixed-linkage (1→3)(1→4)-β-glucan produced by a bacterium. TheS.melilotiML β-glucan participates in bacterial aggregation and biofilm formation and is required for efficient attachment to the roots of a host plant, resembling the biological role of cellulose in other bacteria.

23

GUTSCHE, Birgit, Christoph GRUN, Dieter SCHEUTZOW e Markus HERDERICH. "Tryptophan glycoconjugates in food and human urine*". Biochemical Journal 343, n. 1 (24 settembre 1999): 11–19. http://dx.doi.org/10.1042/bj3430011.

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Evaluating the formation of tryptophan glycoconjugates other than well-established Amadori rearrangement products, HPLC-tandem MS (MS/MS) analysis of human urine collected from several healthy individuals proved the presence of one distinct tryptophan C-glycosyl compound [Horiuchi, Yonekawa, Iwahara, Kanno, Kurihara and Fujise (1994) J. Biochem. (Tokyo) 115, 362-366]. After isolation, unambiguous identification of this novel tryptophan metabolite as 2-(α-mannopyranosyl)-L-tryptophan was achieved by tandem MS combined with NMR spectroscopy including homonuclear COSY, heteronuclear multiple-bond connectivity and 1H-detected heteronuclear multiple-quantum coherence experiments. Remarkably, a thorough evaluation of vicinal proton-proton coupling constants in different solvents and nuclear Overhauser effect experiments demonstrate the predominant axial orientation of the hydroxymethyl group of the hexopyranosyl residue. Likewise this spatial arrangement indicates that the respective α-anomeric C-mannosylhexopyranose is preferentially adopting a 1C4 conformation in acidic methanol. Whereas only one distinct tryptophan mannoconjugate could be observed in human urine, HPLC-MS/MS analysis of food samples for the first time led to the identification of numerous N1-(β-D-hexopyranosyl)-L-tryptophan, 2-(β-D-hexopyranosyl)-L-tryptophan and 1-(1,2,3,4,5-p e n t a h y d r o x y p e n t - 1 - yl) - 1, 2, 3, 4 - t e t r a h y d r o - β - c a r b o l i n e - 3 -carboxylic acid derivatives derived from the condensation of tryptophan with aldohexoses. Taking into consideration the significant differences between profiles and configurations of tryptophan glycoconjugates originating from dietary sources and human urine, C-2 mannosylation of tryptophan residues [de Beer, Vliegenthart, Loeffler and Hofsteenge (1995) Biochemistry 34, 11785-11789] represents a novel enzymic pathway in tryptophan metabolism in humans.

24

Leondaritis, George, Theoni Sarri, Ioannis Dafnis, Antonia Efstathiou e Dia Galanopoulou. "Biochemical and Genetic Evidence for the Presence of Multiple Phosphatidylinositol- and Phosphatidylinositol 4,5-Bisphosphate-Specific Phospholipases C in Tetrahymena". Eukaryotic Cell 10, n. 3 (17 dicembre 2010): 412–22. http://dx.doi.org/10.1128/ec.00272-10.

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ABSTRACT Eukaryotic phosphoinositide-specific phospholipases C (PI-PLC) specifically hydrolyze phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P 2 ], produce the Ca 2+ -mobilizing agent inositol 1,4,5-trisphosphate, and regulate signaling in multicellular organisms. Bacterial PtdIns-specific PLCs, also present in trypanosomes, hydrolyze PtdIns and glycosyl-PtdIns, and they are considered important virulence factors. All unicellular eukaryotes studied so far contain a single PI-PLC-like gene. In this report, we show that ciliates are an exception, since we provide evidence that Tetrahymena species contain two sets of functional genes coding for both bacterial and eukaryotic PLCs. Biochemical characterization revealed two PLC activities that differ in their phosphoinositide substrate utilization, subcellular localization, secretion to extracellular space, and sensitivity to Ca 2+ . One of these activities was identified as a typical membrane-associated PI-PLC activated by low-micromolar Ca 2+ , modestly activated by GTPγS in vitro , and inhibited by the compound U73122 [1-(6-{[17β-3-methoxyestra-1,3,5(10)-trien-17-yl]amino}hexyl)-1H-pyrrole-2,5-dione]. Importantly, inhibition of PI-PLC in vivo resulted in rapid upregulation of PtdIns(4,5)P 2 levels, suggesting its functional importance in regulating phosphoinositide turnover in Tetrahymena . By in silico and molecular analysis, we identified two PLC genes that exhibit significant similarity to bacterial but not trypanosomal PLC genes and three eukaryotic PI-PLC genes, one of which is a novel inactive PLC similar to proteins identified only in metazoa. Comparative studies of expression patterns and PI-PLC activities in three T. thermophila strains showed a correlation between expression levels and activity, suggesting that the three eukaryotic PI-PLC genes are functionally nonredundant. Our findings imply the presence of a conserved and elaborate PI-PLC-Ins(1,4,5)P 3 -Ca 2+ regulator y axis in ciliates.

25

Kraus, George A., e Maria Teresa Molina. "A direct synthesis of c-glycosyl compounds". Journal of Organic Chemistry 53, n. 4 (febbraio 1988): 752–53. http://dx.doi.org/10.1021/jo00239a009.

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26

Somsák, László, Éva Bokor, László Juhász, Sándor Kun, László Lázár, Éva Juhász-Tóth e Marietta Tóth. "New syntheses towards C-glycosyl type glycomimetics". Pure and Applied Chemistry 91, n. 7 (26 luglio 2019): 1159–75. http://dx.doi.org/10.1515/pac-2019-0208.

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Abstract Glycomimetics are compounds that resemble carbohydrate molecules in their chemical structure and/or biological effect. A large variety of compounds can be designed and synthesized to get glycomimetics, however, C-glycosyl derivatives represent one of the most frequently studied subgroup. In the present survey syntheses of a range of five- and six membered C-glycopyranosyl heterocycles, anhydro-aldimine type compounds, exo-glycals, C-glycosyl styrenes, carbon-sulfur bonded oligosaccharide mimics are described. Some of the C-glycopyranosyl azoles, namely 1,2,4-triazoles and imidazoles belong to the most efficient glucose analog inhibitors of glycogen phosphorylase known to date. Biological studies revealed the therapeutical potential of such inhibitors. Other synthetic derivatives offer versatile possibilities to get further glycomimetics.

27

Jimenez-Barbero, Jesus, Juan Felix Espinosa, Juan Luis Asensio, Francisco Javier Canada e Ana Poveda. "ChemInform Abstract: The Conformation of C-Glycosyl Compounds". ChemInform 32, n. 15 (10 aprile 2001): no. http://dx.doi.org/10.1002/chin.200115299.

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Olennikov, Daniil Nikolayevich, Nina Igorevna Kashchenko e Nadezhda Konstantinovna Chirikova. "C-/O-GLYCOSYL FLAVONES OF SILENE ITALICA". chemistry of plant raw material, n. 3 (15 aprile 2019): 119–27. http://dx.doi.org/10.14258/jcprm.2019035110.

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Chemical research of Silene genus focused on the study of terpene compounds including ecdysteroids and triterpenoids, to the detriment of other classes of compounds. One of these poorly estimated group of substances are flavonoids, namely C-/O-glycosyl flavones, widely represented within the family Caryophyllaceae. Early studies revealed the presence of some C-glycosyl flavones (Zemtsova, Dzhumyrko, 1976; Darmogray, 1977), but a detailed study of the flavonoids was not conducted. Application of high performance chromatography with diode-array detection and electrospray ionization mass-spectrometry detection (HPLC-DAD-ESI-MS) allowed to found 14 flavonoids, which are C-, O- and C,O-glycosyl flavones in the aerial part of S. italica of Georgia origin. Ten components were discovered in S. italica for first time. The identified C-glycosides included monoglycosides as isoorientin, isovitexin, isoscoparin (chrysoeryol-6-C-glucoside) and diglycosides as carlinoside (luteolin-6-C-glucoside-8-C-arabinoside), schaftoside (apigenin-6-C-glucoside-8-C-arabinoside), isoschaftoside (luteolin-6-C-arabinoside-8-C-glucoside) and genkwanin-6-C-glucoside-8-C-arabinoside. Two O-glycosides, cosmosiin and cynaroside, and mixed C,O-glycosides as saponarin, isovitexin-2′′-O-arabinoside, isovitexin-6′′-O-arabinoside and O-hexosides od schaftosude and genkwanin-6-C-glucoside- 8-C-arabinoside were not previously identified in Silene genus. The known literature data (Mamadalieva et al., 2014) and the present data demonstrate the useful role of C-/O-glycosyl flavones in the systematics of the genus Silene.

29

Miquel, Nicolas, Gilles Doisneau e Jean-Marie Beau. "Synthesis of 1,2-trans C-glycosyl compounds by reductive samariation of glycosyl iodides". Chemical Communications, n. 23 (2000): 2347–48. http://dx.doi.org/10.1039/b006455f.

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30

Guo, Xue Feng, Yong De Yue, Feng Tang e Jia Sun. "A Study of Characteristic Fragmentation of Different C- and O-Glycosylation Position Flavonoids and their Aglycone by Quadrupole Time-of-Flight Tandem Mass Spectrometry". Advanced Materials Research 781-784 (settembre 2013): 1052–59. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.1052.

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Flavonoids are important bioactive natural compounds, so the differentiation and structural characterization of flavonoids are important research topics. This research results provided valuable mass spectral data and reliable information for the identification of differentC- andO-glycosylation position flavonoids and their aglycone. The high resolution electrospray ionization quadrupole time-of-flight tandem mass spectrometry was employed to identify one 8-C-glycosyl flavonoid, one 4-O-glycosyl, one 7-O-glycosyl, and two 3-O-glycosyl flavonoids and four aglycone in negative and positive ion mode with collision-induced dissociation. The characteristic ions of differentC- andO-glycosylation position flavonoids and their aglycone were summarized and the fragmentation pathways were proposed in negative and positive ion mode. The MS/MS spectra obtained by UHPLC/Q-TOF-MS/MS analysis could be used for the structural characterization and differentiation of these compounds. These results have practical applications for the rapid identification and structural characterization of these compounds present in crude bioactive extracts or mixtures.

31

Lee, E. A., J. M. Staebler, C. Grainger e M. E. Snook. "Robustness of QTLs across germplasm pools using a model quantitative trait". Genome 52, n. 1 (gennaio 2009): 39–48. http://dx.doi.org/10.1139/g08-100.

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Knowledge of the inheritance of C-glycosyl flavone synthesis in maize ( Zea mays L.) silk tissues has been acquired through detailed genetic studies involving primarily germplasm from the Corn Belt Dent race. To test the robustness of this genetic knowledge, we examined C-glycosyl flavone synthesis in a genetically distinct germplasm pool, popcorn. C-glycosyl flavone profiles and levels and the involvement of three specific genes/quantitative trait loci (p, pr1, and sm1) in C-glycosyl flavone synthesis were examined in popcorn germplasm representing at least two races and various diverse geographic regions. Twenty-four inbred lines and 23 hybrids involving these inbred lines and inbred line R17 were characterized for their flavone profiles and levels in silk tissues. Two F2 mapping populations were constructed to examine the involvement of p, pr1, and sm1 on C-glycosyl flavone synthesis. C-glycosyl flavone levels threefold higher than previously reported in Corn Dent Belt materials and a novel class of compounds were discovered. The gene action of sm1 was different, the functional p allele was not always dominant, and pr1 did not affect maysin synthesis. Based on this rather simplistic “model” quantitative trait, it appears that caution should be exercised when attempting to apply quantitative trait locus knowledge accumulated in one germplasm base to a germplasm base that is known to be distinctly unique.

32

Xu, Lin-Yi, Nai-Li Fan e Xiang-Guo Hu. "Recent development in the synthesis of C-glycosides involving glycosyl radicals". Organic & Biomolecular Chemistry 18, n. 27 (2020): 5095–109. http://dx.doi.org/10.1039/d0ob00711k.

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Abstract (sommario):

C-Glycosylation involving glycosyl radical intermediates is a particularly effective approach to access C-glycosides, which are core units of a great number of natural products, bioactive compounds and marketed drugs.

33

Xie, Juan, Mickaël Ménand e Jean-Marc Valéry. "Regioselective debenzylation of C-glycosyl compounds by boron trichloride". Carbohydrate Research 340, n. 3 (febbraio 2005): 481–87. http://dx.doi.org/10.1016/j.carres.2004.12.001.

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34

GIESE, B., e H. G. ZEITZ. "ChemInform Abstract: C-Glycosyl Compounds from Free Radical Reactions". ChemInform 28, n. 32 (3 agosto 2010): no. http://dx.doi.org/10.1002/chin.199732234.

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35

Szennyes, Eszter, Éva Bokor, Peter Langer, Gyöngyi Gyémánt, Tibor Docsa, Ádám Sipos e László Somsák. "The first general synthesis of 2-C-(β-d-glycopyranosyl)pyrimidines and their evaluation as inhibitors of some glycoenzymes". New Journal of Chemistry 42, n. 21 (2018): 17439–46. http://dx.doi.org/10.1039/c8nj04035d.

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36

Miquel, Nicolas, Gilles Doisneau e Jean-Marie Beau. "ChemInform Abstract: Synthesis of 1,2-trans C-Glycosyl Compounds by Reductive Samariation of Glycosyl Iodides." ChemInform 32, n. 14 (3 aprile 2001): no. http://dx.doi.org/10.1002/chin.200114208.

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37

Lin, Li, Qiang Shen, Guo-Rong Chen e Juan Xie. "β-C-Glycosiduronic acids and β-C-glycosyl compounds: New PTP1B inhibitors". Bioorganic & Medicinal Chemistry Letters 18, n. 24 (dicembre 2008): 6348–51. http://dx.doi.org/10.1016/j.bmcl.2008.10.091.

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38

Mora Flores, Erwin W., María Laura Uhrig e Al Postigo. "Photocatalyzed reductive fluoroalkylation of 2-acetoxyglycals towards the stereoselective synthesis of α-1-fluoroalkyl-C-glycosyl derivatives". Organic & Biomolecular Chemistry 18, n. 42 (2020): 8724–34. http://dx.doi.org/10.1039/d0ob01914c.

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Abstract (sommario):

A benign, efficient, regio- and stereoselective protocol for the syntheses of α-1-fluoroalkyl-C-glycosyl compounds bearing CF₃, C₄F₉, and C₆F₁₃ substituents on the anomeric carbon has been developed.

39

Gulbe, Krista, Jevgeņija Lugiņina, Edijs Jansons, Artis Kinens e Māris Turks. "Metal-free glycosylation with glycosyl fluorides in liquid SO2". Beilstein Journal of Organic Chemistry 17 (29 aprile 2021): 964–76. http://dx.doi.org/10.3762/bjoc.17.78.

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Liquid SO2 is a polar solvent that dissolves both covalent and ionic compounds. Sulfur dioxide possesses also Lewis acid properties, including the ability to covalently bind Lewis basic fluoride ions in a relatively stable fluorosulfite anion (FSO2−). Herein we report the application of liquid SO2 as a promoting solvent for glycosylation with glycosyl fluorides without any external additive. By using various temperature regimes, the method is applied for both armed and disarmed glucose and mannose-derived glycosyl fluorides in moderate to excellent yields. A series of pivaloyl-protected O- and S-mannosides, as well as one example of a C-mannoside, are synthesized to demonstrate the scope of the glycosyl acceptors. The formation of the fluorosulfite species during the glycosylation with glycosyl fluorides in liquid SO2 is proved by 19F NMR spectroscopy. A sulfur dioxide-assisted glycosylation mechanism that proceeds via solvent separated ion pairs is proposed, whereas the observed α,β-selectivity is substrate-controlled and depends on the thermodynamic equilibrium.

40

Nawwar, Mahmoud, Amani El-Mousallami, Sahar Hussein, Amani Hashem, Mona Mousa, Ulrike Lindequist e Michael Linscheid. "Three New Di-O-glycosyl-C-glucosyl Flavones from the Leaves of Caesalpinia ferrea Mart." Zeitschrift für Naturforschung C 69, n. 9-10 (1 ottobre 2014): 357–62. http://dx.doi.org/10.5560/znc.2014-0113.

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Abstract Three hitherto unknown di-O-xylosyl-C-glycosyl flavones were isolated from the leaves of Caesalpinia ferrea. The structures of all isolated compounds were elucidated by conventional methods and spectroscopic analysis, including 1D and 2D NMR, as well as by HRESIMS.

41

Talamond, Pascale, Geneviève Conejero, Jean-Luc Verdeil e Jean-Luc Poëssel. "Isolation of C-glycosyl Xanthones from Coffea pseudozanguebariae and Their Location". Natural Product Communications 6, n. 12 (dicembre 2011): 1934578X1100601. http://dx.doi.org/10.1177/1934578x1100601223.

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The biochemical composition of leaves from Coffea pseudozanguebariae, a wild caffeine-free coffee species, was determined. Two phenolic compounds were extracted from leaves, separated and characterized. Their structures were elucidated by mass spectrometry, and 1D and 2D NMR spectroscopy and were shown to be mangiferin (1) and isomangiferin (2), which were the main polyphenol products. Multiphoton fluorescence imaging was performed to visualize polyphenol distribution in leaf cross sections. Consistent biochemical analysis cell imaging techniques on leaves revealed yellow fluorescence in the epidermis and parenchyma cells corresponding to xanthone compounds.

42

Witczak, Z. J. "Synthesis of C-glycosyl compounds and other natural products from levoglucosenone". Pure and Applied Chemistry 66, n. 10-11 (1 gennaio 1994): 2189–92. http://dx.doi.org/10.1351/pac199466102189.

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43

Martin, O. R. "ChemInform Abstract: Toward Azaglycoside Mimics: Aza-C-glycosyl Compounds and Homoazaglycosides". ChemInform 30, n. 22 (15 giugno 2010): no. http://dx.doi.org/10.1002/chin.199922263.

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44

Thien, Hoang-Trang Tran, Alexandre Novoa, Nadia Pellegrini-Moïse, Françoise Chrétien, Claude Didierjean e Yves Chapleur. "Tetrasubstituted C-Glycosylidenes and C-Glycosyl Compounds from Di- and Monobromo-Substituted exo-Glycals". European Journal of Organic Chemistry 2011, n. 34 (6 ottobre 2011): 6939–51. http://dx.doi.org/10.1002/ejoc.201100949.

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45

Lee, E. A., P. F. Byrne, M. D. McMullen, M. E. Snook, B. R. Wiseman, N. W. Widstrom e E. H. Coe. "Genetic Mechanisms Underlying Apimaysin and Maysin Synthesis and Corn Earworm Antibiosis in Maize (Zea mays L.)". Genetics 149, n. 4 (1 agosto 1998): 1997–2006. http://dx.doi.org/10.1093/genetics/149.4.1997.

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Abstract (sommario):

Abstract C-glycosyl flavones in maize silks confer resistance (i.e., antibiosis) to corn earworm (Helicoverpa zea [Boddie]) larvae and are distinguished by their B-ring substitutions, with maysin and apimaysin being the di- and monohydroxy B-ring forms, respectively. Herein, we examine the genetic mechanisms underlying the synthesis of maysin and apimaysin and the corresponding effects on corn earworm larval growth. Using an F2 population, we found a quantitative trait locus (QTL), rem1, which accounted for 55.3% of the phenotypic variance for maysin, and a QTL, pr1, which explained 64.7% of the phenotypic variance for apimaysin. The maysin QTL did not affect apimaysin synthesis, and the apimaysin QTL did not affect maysin synthesis, suggesting that the synthesis of these closely related compounds occurs independently. The two QTLs, rem1 and pr1, were involved in a significant epistatic interaction for total flavones, suggesting that a ceiling exists governing the total possible amount of C-glycosyl flavone. The maysin and apimaysin QTLs were significant QTLs for corn earworm antibiosis, accounting for 14.1% (rem1) and 14.7% (pr1) of the phenotypic variation. An additional QTL, represented by umc85 on the short arm of chromosome 6, affected antibiosis (R2 = 15.2%), but did not affect the synthesis of the C-glycosyl flavones.

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Riemann, I., W. D. Fessner, M. A. Papadopoulos e M. Knorst. "C-Glycosides by Aqueous Condensation of β-Dicarbonyl Compounds with Unprotected Sugars". Australian Journal of Chemistry 55, n. 2 (2002): 147. http://dx.doi.org/10.1071/ch02012.

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Condensation of 1,3-diketones with unprotected aldoses in water, under mildly alkaline conditions, provides a�convenient and effective route to C-glycosidic ketones in high yields. Reactions usually proceed with high β`anomeric' stereoselectivity because product composition is determined by thermodynamic control. Mechanistically, the condensation follows a typical Knoevenagel scheme, after which an intramolecular oxa-Michael cyclization determines C-glycoside configuration by following an exo- or endo-trig pathway. With open-chain 1,3-diketones, an ensuing retro-Claisen fragmentation occurs to furnish simple glycosyl monoketones. The C-glycosides then slowly further dehydrate under the reaction conditions to give 2,5-disubstituted furans.

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Khodair, Ahmed I., e Richard R. Schmidt. "Synthesis of C-glycosyl compounds of N-acetylneuraminic acid from d-gluconolactone". Carbohydrate Research 337, n. 21-23 (novembre 2002): 1967–78. http://dx.doi.org/10.1016/s0008-6215(02)00176-3.

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Neuman, Alain, François Longchambon, Oukacha Abbes, Hélène Gillier-Pandraud, Serge Pérez, Dominique Rouzaud e Pierre Sinaÿ. "Conformational features of C-glycosyl compounds: Crystal structure and molecular modelling of “methyl C-gentiobioside”". Carbohydrate Research 195, n. 2 (gennaio 1990): 187–97. http://dx.doi.org/10.1016/0008-6215(90)84166-r.

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Prakash, Indra, Bin Wang, Gil Ma, George Harrigan, Steven F. Sukits, Krishna P. Devkota, Romila D. Charan, Ryan Donovan e Tara M. Snyder. "Novel Ent-Kaurene Glycosides with Eight Glycosyl Units from Stevia rebaudiana". Natural Product Communications 13, n. 2 (febbraio 2018): 1934578X1801300. http://dx.doi.org/10.1177/1934578x1801300204.

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Abstract (sommario):

Several steviol glycosides from Stevia rebaudiana are associated with extremely potent sweetness and are sought-after as low-calorie alternatives to sucrose. With the exception of a few nine sugar glycosides, steviol glycosides described in the scientific literatures contain less than a total of seven glycosyl units. We present here two new steviol glycosides, rebaudioside VIIIa (1) and VIIIb (2) containing eight sugar units isolated from S. rebaudiana Bertoni. The complete structure elucidation of these ent -kaurene diterpene glycosides with eight sugar units was completed using 1D- and 2D-NMR spectroscopy experiments (1H, 13C, 1H-1H COSY, 1H-13C HSQC-DEPT, 1H-13C HMBC, 1D TOCSY, and 1H-1H ROESY) and mass spectral data. Both compounds have four glycosyl units each attached to the C-13 and C-19 positions of aglycone core but vary in the glycosylation pattern and number of glucose and rhamnose units. This report therefore expands the catalog of highly glycosylated components from S. rebaudiana.

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Bandzouzi, Alphonse, e Yves Chapleur. "Dichloromethylenation of 1,4-lactones. A new access to 1-deoxy-1-C-methyl-C-glycosyl compounds". Carbohydrate Research 171, n. 1 (dicembre 1987): 13–24. http://dx.doi.org/10.1016/s0008-6215(00)90875-9.

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