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Special Issue "Advances in Carbohydrate Chemistry 2012"

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A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (30 June 2012)

Special Issue Editors

Guest Editor
Dr. Trinidad Velasco-Torrijos

Department of Chemistry, National University of Ireland, Maynooth, Co. Kildare, Ireland
Website | E-Mail
Interests: carbohydrate chemistry; glycoconjugates; glycopeptides; glycolipids; glycomimetics, molecular scaffolds
Guest Editor
Dr. Vito Ferro

School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
Website | E-Mail
Interests: carbohydrate chemistry; medicinal chemistry; heparanase inhibitors; heparan sulfate mimetics

Special Issue Information

Dear Colleagues,

The complex and important role of carbohydrate conjugates in biological systems has been validated with the consolidation of the field of Glycobiology.  This has been prompted by tremendous advances in analytical techniques that have facilitated the isolation and structural characterization of complex glycoconjugates. However, the availability of these materials from natural sources is often very limited. Organic chemists have addressed this problem, and over the last few decades, the development of efficient glycosylation methodologies has allowed the synthesis of naturally occurring oligosaccharides and glycomimetics. These compounds not only serve as useful tools to glycobiologists, but are also of interest for their potential applications as therapeutics, in biomedical research and nanoscience.

There are still many unsolved challenges facing carbohydrate chemists, to name but a few, the improvement of the stereoselectivity of certain glycosylation reactions and the development of synthetic strategies that avoid lengthy protection/deprotection steps in the synthesis of oligosaccharides. In addition to this, a new role for carbohydrates as renewable raw materials is emerging, in view of the need to investigate sustainable chemical processes. The unique structural diversity, optical purity and natural availability of mono and oligosaccharides make them ideal candidates in this regard. We would like to invite scientists in these fields to submit research articles and comprehensive reviews addressing the above mentioned topics, and carbohydrate chemistry in general, for publication in this special issue.

Dr. Trinidad Velasco-Torrijos
Dr. Vito Ferro
Guest Editors

Keywords

  • carbohydrate chemistry
  • glycoconjugates
  • glycopeptides
  • glycolipids
  • glycomimetics
  • molecular scaffolds
  • sustainable carbohydrate raw materials
  • carbohydrate nanostructures
  • bioactive compounds

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Published Papers (15 papers)

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Research

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Open AccessArticle Artificial and Natural Sialic Acid Precursors Influence the Angiogenic Capacity of Human Umbilical Vein Endothelial Cells
Molecules 2013, 18(3), 2571-2586; doi:10.3390/molecules18032571
Received: 9 October 2012 / Revised: 6 February 2013 / Accepted: 19 February 2013 / Published: 26 February 2013
Cited by 4 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
N-acetylneuraminic acid (Neu5Ac) represents the most common terminal carbohydrate residue in many mammalian glycoconjugates and is directly involved in a number of different physiological as well as pathological cellular processes. Endogenous sialic acids derive from the biosynthetic precursor molecule N-acetyl-D-mannosamine (ManNAc).
[...] Read more.
N-acetylneuraminic acid (Neu5Ac) represents the most common terminal carbohydrate residue in many mammalian glycoconjugates and is directly involved in a number of different physiological as well as pathological cellular processes. Endogenous sialic acids derive from the biosynthetic precursor molecule N-acetyl-D-mannosamine (ManNAc). Interestingly, N-acyl-analogues of D-mannosamine (ManN) can also be incorporated and converted into corresponding artificial sialic acids by eukaryotic cells. Within this study, we optimized a protocol for the chemical synthesis of various peracetylated ManN derivatives resulting in yields of approximately 100%. Correct molecular structures of the obtained products ManNAc, N-propanoyl-ManN (ManNProp) and N-butyl-ManN (ManNBut) were verified by GC-, ESI-MS- and NMR-analyses. By applying these substances to human umbilical vein endothelial cells (HUVECs), we could show that each derivative was metabolized to the corresponding N-acylneuraminic acid variant and subsequently incorporated into nascent glycoproteins. To investigate whether natural and/or artificial sialic acid precursors are able to modulate the angiogenic capacity of HUVECs, a spheroid assay was performed. By this means, an increase in total capillary length has been observed when cells incorporated N-butylneuraminic acid (Neu5But) into their glycoconjugates. In contrast, the natural precursor ManNAc inhibited the growth of capillaries. Thus, sialic acid precursors may represent useful agents to modulate blood vessel formation. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessArticle The Binding Affinity and Molecular Basis of the Structure-Binding Relationship between Urinary Tamm-Horsfall Glycoprotein and Tumor Necrosis Factor-α
Molecules 2012, 17(10), 11978-11989; doi:10.3390/molecules171011978
Received: 13 July 2012 / Revised: 26 September 2012 / Accepted: 8 October 2012 / Published: 11 October 2012
Cited by 4 | PDF Full-text (936 KB) | HTML Full-text | XML Full-text
Abstract
In a previous study we noted significant THP binding to TNF-α, but did not explore the molecular basis of the structure-binding relationship. In this study, we used lectin-binding ELISA to assess the carbohydrate compositions of THP, BSA, IgG, TNF-α, and IFN-g. We identified
[...] Read more.
In a previous study we noted significant THP binding to TNF-α, but did not explore the molecular basis of the structure-binding relationship. In this study, we used lectin-binding ELISA to assess the carbohydrate compositions of THP, BSA, IgG, TNF-α, and IFN-g. We identified β(1,4)-N-acetylglucosamine oligomers (GlcNAc) and GlcNAc/branched mannose in BSA, IgG, TNF-α, and THP, but not in IFN-g. These carbohydrate moieties mediated binding with THP. Small amounts of Siaα(2,3)Gal/ GalNAc, Sia(2,6)Gal/GalNAc, and mannose residues were also present in THP and TNF-α. Binding affinity (Kd) between THP and TNF-α by Scatchard plot analysis was 1.4–1.7 × 10−6 M, lower than antigen-antibody or ligand-receptor binding affinities. To elucidate the structure-binding relationship of THP-TNF-α, THP was digested with neuraminidase, β-galactosidase, O-sialoglycoprotein endopeptidase, carboxypeptidase Y, or proteinase K. β-galactosidase increased binding capacity of THP for TNF-α. Monosaccharide inhibition suggested that α-methyl-D-mannoside, GlcNAc, and GalNAc, but not sialic acid, suppress THP-TNF-α binding as detected by ELISA. We conclude that sugar-lectin and sugar-protein interactions between cognate sites in THP and TNF-α mediate their binding. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle Syntheses of Sulfo-Glycodendrimers Using Click Chemistry and Their Biological Evaluation
Molecules 2012, 17(10), 11877-11896; doi:10.3390/molecules171011877
Received: 23 July 2012 / Revised: 5 September 2012 / Accepted: 18 September 2012 / Published: 9 October 2012
Cited by 5 | PDF Full-text (839 KB) | HTML Full-text | XML Full-text
Abstract
A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc) have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated
[...] Read more.
A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc) have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated dendrimers showed affinity for proteins, including the lectin wheat germ agglutinin and amyloid beta peptide (1-42). The dendrimers of G1 and G2 in particular showed the largest affinity for the proteins. The addition of the sulfonated GlcNAc dendrimers of G1 and G2 exhibited an inhibition effect on the aggregation of the amyloid beta peptide, reduced the b-sheet conformation, and led to a reduction in the level of nanofiber formation. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle A Concise Synthesis of Glycolipids Based on Aspartic Acid Building Blocks
Molecules 2012, 17(10), 11346-11362; doi:10.3390/molecules171011346
Received: 31 July 2012 / Revised: 15 September 2012 / Accepted: 21 September 2012 / Published: 25 September 2012
Cited by 3 | PDF Full-text (288 KB) | HTML Full-text | XML Full-text
Abstract
L-Aspartic acid building blocks bearing galactosyl moieties were used to synthesise glycolipid mimetics of variable hydrocarbon chain length. The glycolipids were readily prepared through amide bond formation using the TBTU/HOBt coupling methodology. It was observed that, under these conditions, activation of the α-carboxylic
[...] Read more.
L-Aspartic acid building blocks bearing galactosyl moieties were used to synthesise glycolipid mimetics of variable hydrocarbon chain length. The glycolipids were readily prepared through amide bond formation using the TBTU/HOBt coupling methodology. It was observed that, under these conditions, activation of the α-carboxylic acid of the intermediates led to near complete racemisation of the chiral centre if the reaction was carried out in the presence of a base such as triethylamine. The enantiomerically pure glycolipids were obtained after careful consideration of the synthetic sequence and by performing the coupling reactions in the absence of base. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessCommunication Inhibition of Burkholderia multivorans Adhesion to Lung Epithelial Cells by Bivalent Lactosides
Molecules 2012, 17(9), 10065-10071; doi:10.3390/molecules170910065
Received: 10 July 2012 / Revised: 2 August 2012 / Accepted: 6 August 2012 / Published: 24 August 2012
PDF Full-text (211 KB)
Abstract
Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly
[...] Read more.
Burkholderia cepacia complex (Bcc) is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly colonised patients, Burkholderia multivorans, continues to be acquired from the environment. Development of therapies which can prevent or reduce the risk of colonization on exposure to Bcc in the environment would be a better alternative to antimicrobial agents. Previously, it has been shown that Bcc strains bound to many glycolipid receptors on lung epithelia. Using a real-time PCR method to quantify the levels of binding of B. multivorans to the lung epithelial cells, we have examined glycoconjugate derivatives for their potential to inhibit host cell attachment. Bivalent lactosides previously shown to inhibit galectin binding significantly reduced the attachment of B. multivorans to CF lung epithelial cells at micromolar concentrations. This was in contrast to monosaccharides and lactose, which were only effective in the millimolar range. Development of glycoconjugate therapies such as these, which inhibit attachment to lung epithelial cells, represent an alternative means of preventing infection with inherently antimicrobially resistant pathogens such as B. multivorans. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle Anti-metastatic Semi-synthetic Sulfated Maltotriose C-C Linked Dimers. Synthesis and Characterisation
Molecules 2012, 17(8), 9912-9930; doi:10.3390/molecules17089912
Received: 4 July 2012 / Revised: 8 August 2012 / Accepted: 9 August 2012 / Published: 17 August 2012
Cited by 6 | PDF Full-text (416 KB) | XML Full-text | Supplementary Files
Abstract
This manuscript describes the preparation and the spectroscopic characterisation of semi-synthetic sulfated maltotriose C-C linked dimers (SMTCs) where the natural C-O-C anomeric bond was substituted by one direct central C-C bond. This C-C bond induces conformation and flexibility changes with respect to the
[...] Read more.
This manuscript describes the preparation and the spectroscopic characterisation of semi-synthetic sulfated maltotriose C-C linked dimers (SMTCs) where the natural C-O-C anomeric bond was substituted by one direct central C-C bond. This C-C bond induces conformation and flexibility changes with respect to the usual anomeric bond. SMTCs neutral precursors came from maltotriosyl bromide electroreduction through maltotriosyl radical intermediate dimerisation. The new C-C bond configuration, named for convenience a,a, a,b and b,b as the natural anomeric bond, dictated the statistic ratio formation of three diastereoisomers. They were separated by silica gel flash chromatography followed by semi preparative HPLC chromatography. Each diastereoisomer was exhaustively sulfated to afford the corresponding SMTCs. SMTCs were huge characterised by NMR spectroscopy which provided the sulfation degree, too. a,a and a,b were found quite homogeneous samples with a high degree of sulfation (85–95%). b,b appeared a non-homogeneous sample whose average sulfation degree was evaluated at around 78%. Mass spectroscopy experiments confirmed the sulfation degree range. Some considerations were proposed about SMTCs structure-biological properties. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessArticle Synthesis of Disaccharides Containing 6-Deoxy-a-L-talose as Potential Heparan Sulfate Mimetics
Molecules 2012, 17(8), 9790-9802; doi:10.3390/molecules17089790
Received: 28 June 2012 / Revised: 5 August 2012 / Accepted: 9 August 2012 / Published: 15 August 2012
Cited by 2 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A 6-deoxy-a-L-talopyranoside acceptor was readily prepared from methyl a-L-rhamnopyranoside and glycosylated with thiogalactoside donors using NIS/TfOH as the promoter to give good yields of the desired a-linked disaccharide (69–90%). Glycosylation with a 2-azido-2-deoxy-D-glucosyl trichloroacetimidate donor was not completely stereoselective (a:b = 6:1), but
[...] Read more.
A 6-deoxy-a-L-talopyranoside acceptor was readily prepared from methyl a-L-rhamnopyranoside and glycosylated with thiogalactoside donors using NIS/TfOH as the promoter to give good yields of the desired a-linked disaccharide (69–90%). Glycosylation with a 2-azido-2-deoxy-D-glucosyl trichloroacetimidate donor was not completely stereoselective (a:b = 6:1), but the desired a-linked disaccharide could be isolated in good overall yield (60%) following conversion into its corresponding tribenzoate derivative. The disaccharides were designed to mimic the heparan sulfate (HS) disaccharide GlcN(2S,6S)-IdoA(2S). However, the intermediates readily derived from these disaccharides were not stable to the sulfonation/deacylation conditions required for their conversion into the target HS mimetics. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle Accumulation of Unusual Gangliosides GQ3 and GP3 in Breast Cancer Cells Expressing the GD3 Synthase
Molecules 2012, 17(8), 9559-9572; doi:10.3390/molecules17089559
Received: 18 June 2012 / Revised: 20 July 2012 / Accepted: 6 August 2012 / Published: 10 August 2012
Cited by 8 | PDF Full-text (457 KB) | HTML Full-text | XML Full-text
Abstract
Glycosphingolipids from the ganglio-series are usually classified in four series according to the presence of 0 to 3 sialic acid residues linked to lactosylceramide. The transfer of sialic acid is catalyzed in the Golgi apparatus by specific sialyltransferases that show high specificity toward
[...] Read more.
Glycosphingolipids from the ganglio-series are usually classified in four series according to the presence of 0 to 3 sialic acid residues linked to lactosylceramide. The transfer of sialic acid is catalyzed in the Golgi apparatus by specific sialyltransferases that show high specificity toward glycolipid substrates. ST8Sia I (EC 2.4.99.8, SAT-II, SIAT 8a) is the key enzyme controlling the biosynthesis of b- and c-series gangliosides. ST8Sia I is expressed at early developmental stages whereas in adult human tissues, ST8Sia I transcripts are essentially detected in brain. ST8Sia I together with b- and c-series gangliosides are also over-expressed in neuroectoderm-derived malignant tumors such as melanoma, glioblastoma, neuroblastoma and in estrogen receptor (ER) negative breast cancer, where they play a role in cell proliferation, migration, adhesion and angiogenesis. We have stably expressed ST8Sia I in MCF-7 breast cancer cells and analyzed the glycosphingolipid composition of wild type (WT) and GD3S+ clones. As shown by mass spectrometry, MCF-7 expressed a complex pattern of neutral and sialylated glycosphingolipids from globo- and ganglio-series. WT MCF-7 cells exhibited classical monosialylated gangliosides including GM3, GM2, and GM1a. In parallel, the expression of ST8Sia I in MCF-7 GD3S+ clones resulted in a dramatic change in ganglioside composition, with the expression of b- and c-series gangliosides as well as unusual tetra- and pentasialylated lactosylceramide derivatives GQ3 (II3Neu5Ac4-Gg2Cer) and GP3 (II3Neu5Ac5-Gg2Cer). This indicates that ST8Sia I is able to act as an oligosialyltransferase in a cellular context. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessArticle Design and Synthesis of a Novel Ganglioside Ligand for Influenza A Viruses
Molecules 2012, 17(8), 9590-9620; doi:10.3390/molecules17089590
Received: 9 July 2012 / Revised: 6 August 2012 / Accepted: 8 August 2012 / Published: 10 August 2012
Cited by 4 | PDF Full-text (444 KB) | HTML Full-text | XML Full-text
Abstract
A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between
[...] Read more.
A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between the non-reducing end of the oligosaccharide and the cyclic glucosylceramide moiety. Examination of its binding activity to influenza A viruses revealed that the new ligand is recognized by Neua2-3 and 2-6 type viruses. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessArticle Synthesis, Antigenicity Against Human Sera and Structure-Activity Relationships of Carbohydrate Moieties from Toxocara larvae and Their Analogues
Molecules 2012, 17(8), 9023-9042; doi:10.3390/molecules17089023
Received: 21 June 2012 / Revised: 20 July 2012 / Accepted: 23 July 2012 / Published: 30 July 2012
Cited by 7 | PDF Full-text (560 KB) | HTML Full-text | XML Full-text
Abstract
Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (A), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (B), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (C), Fucα1-2Galβ1-3GalNAcα1-OR (D
[...] Read more.
Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the Galβ1-3GalNAc core of the TES-glycoprotein antigen obtained from larvae of the parasite Toxocara and their analogues have been accomplished. Trisaccharides Fuc2Meα1-2Gal4Meβ1-3GalNAcα1-OR (A), Fucα1-2Gal4Meβ1-3GalNAcα1-OR (B), Fuc2Meα1-2Galβ1-3GalNAcα1-OR (C), Fucα1-2Galβ1-3GalNAcα1-OR (D) and a disaccharide Fuc2Meα1-2Gal4Meβ1-OR (E) (R = biotinylated probe) were synthesized by block synthesis using 5-(methoxycarbonyl)pentyl-2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl-(1®3)-2-azide-4-O-benzyl-2-deoxy-α-D-galactopyranoside as a common glycosyl acceptor. We examined the antigenicity of these five oligosaccharides by enzyme linked immunosorbent assay (ELISA). Our results demonstrate that the O-methyl groups in these oligosaccharides are important for their antigenicity and the biotinylated oligosaccharides A, B, C and E have high serodiagnostic potential to detect infections caused by Toxocara larvae. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle Synthesis and Sensory Evaluation of ent-Kaurane Diterpene Glycosides
Molecules 2012, 17(8), 8908-8916; doi:10.3390/molecules17088908
Received: 29 June 2012 / Revised: 18 July 2012 / Accepted: 23 July 2012 / Published: 26 July 2012
Cited by 7 | PDF Full-text (230 KB) | HTML Full-text | XML Full-text
Abstract
Catalytic hydrogenation of the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana, namely rubusoside, stevioside, and rebaudioside-A has been carried out using Pd(OH)2 and their corresponding dihydro derivatives have been isolated as the products. Synthesis of reduced steviol glycosides was
[...] Read more.
Catalytic hydrogenation of the three ent-kaurane diterpene glycosides isolated from Stevia rebaudiana, namely rubusoside, stevioside, and rebaudioside-A has been carried out using Pd(OH)2 and their corresponding dihydro derivatives have been isolated as the products. Synthesis of reduced steviol glycosides was performed using straightforward chemistry and their structures were characterized on the basis of 1D and 2D NMR spectral data and chemical studies. Also, we report herewith the sensory evaluation of all the reduced compounds against their corresponding original steviol glycosides and sucrose for the sweetness property of these molecules. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle Application of Paramagnetic NMR-Validated Molecular Dynamics Simulation to the Analysis of a Conformational Ensemble of a Branched Oligosaccharide
Molecules 2012, 17(6), 6658-6671; doi:10.3390/molecules17066658
Received: 11 April 2012 / Revised: 29 May 2012 / Accepted: 29 May 2012 / Published: 31 May 2012
Cited by 12 | PDF Full-text (696 KB)
Abstract
Oligosaccharides of biological importance often exhibit branched covalent structures and dynamic conformational multiplicities. Here we report the application of a method that we developed, which combined molecular dynamics (MD) simulations and lanthanide-assisted paramagnetic NMR spectroscopy, to evaluate the dynamic conformational ensemble of a
[...] Read more.
Oligosaccharides of biological importance often exhibit branched covalent structures and dynamic conformational multiplicities. Here we report the application of a method that we developed, which combined molecular dynamics (MD) simulations and lanthanide-assisted paramagnetic NMR spectroscopy, to evaluate the dynamic conformational ensemble of a branched oligosaccharide. A lanthanide-chelating tag was attached to the reducing end of the branched tetrasaccharide of GM2 ganglioside to observe pseudocontact shifts as the source of long distance information for validating the conformational ensemble derived from MD simulations. By inspecting the results, the conformational space of the GM2 tetrasaccharide was compared with that of its nonbranched derivative, the GM3 trisaccharide. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Open AccessArticle Glycosylation of Vanillin and 8-Nordihydrocapsaicin by Cultured Eucalyptus perriniana Cells
Molecules 2012, 17(5), 5013-5020; doi:10.3390/molecules17055013
Received: 29 March 2012 / Revised: 17 April 2012 / Accepted: 23 April 2012 / Published: 2 May 2012
Cited by 4 | PDF Full-text (219 KB) | Supplementary Files
Abstract
Glycosylation of vanilloids such as vanillin and 8-nordihydrocapsaicin by cultured plant cells of Eucalyptus perriniana was studied. Vanillin was converted into vanillin 4-O-b-D-glucopyranoside, vanillyl alcohol, and 4-O-b-D-glucopyranosylvanillyl alcohol by E. perriniana cells. Incubation of cultured E. perriniana cells with
[...] Read more.
Glycosylation of vanilloids such as vanillin and 8-nordihydrocapsaicin by cultured plant cells of Eucalyptus perriniana was studied. Vanillin was converted into vanillin 4-O-b-D-glucopyranoside, vanillyl alcohol, and 4-O-b-D-glucopyranosylvanillyl alcohol by E. perriniana cells. Incubation of cultured E. perriniana cells with 8-nor- dihydrocapsaicin gave 8-nordihydrocapsaicin 4-O-b-D-glucopyranoside and 8-nordihydro- capsaicin 4-O-b-D-gentiobioside. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
Open AccessArticle 1D 13C-NMR Data as Molecular Descriptors in Spectra — Structure Relationship Analysis of Oligosaccharides
Molecules 2012, 17(4), 3818-3833; doi:10.3390/molecules17043818
Received: 9 February 2012 / Revised: 19 March 2012 / Accepted: 23 March 2012 / Published: 28 March 2012
Cited by 1 | PDF Full-text (310 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Spectra-structure relationships were investigated for estimating the anomeric configuration, residues and type of linkages of linear and branched trisaccharides using 13C-NMR chemical shifts. For this study, 119 pyranosyl trisaccharides were used that are trimers of the α or β anomers of D-glucose, D-galactose, D-mannose,
[...] Read more.
Spectra-structure relationships were investigated for estimating the anomeric configuration, residues and type of linkages of linear and branched trisaccharides using 13C-NMR chemical shifts. For this study, 119 pyranosyl trisaccharides were used that are trimers of the α or β anomers of D-glucose, D-galactose, D-mannose, L-fucose or L-rhamnose residues bonded through a or b glycosidic linkages of types 1→2, 1→3, 1→4, or 1→6, as well as methoxylated and/or N-acetylated amino trisaccharides. Machine learning experiments were performed for: (1) classification of the anomeric configuration of the first unit, second unit and reducing end; (2) classification of the type of first and second linkages; (3) classification of the three residues: reducing end, middle and first residue; and (4) classification of the chain type. Our previously model for predicting the structure of disaccharides was incorporated in this new model with an improvement of the predictive power. The best results were achieved using Random Forests with 204 di- and trisaccharides for the training set—it could correctly classify 83%, 90%, 88%, 85%, 85%, 75%, 79%, 68% and 94% of the test set (69 compounds) for the nine tasks, respectively, on the basis of unassigned chemical shifts. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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Review

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Open AccessReview Chemistry and Applications of Polysaccharide Solutions in Strong Electrolytes/Dipolar Aprotic Solvents: An Overview
Molecules 2013, 18(1), 1270-1313; doi:10.3390/molecules18011270
Received: 26 October 2012 / Revised: 2 January 2013 / Accepted: 9 January 2013 / Published: 21 January 2013
Cited by 12 | PDF Full-text (989 KB)
Abstract
Biopolymers and their derivatives are being actively investigated as substitutes for petroleum-based polymers. This has generated an intense interest in investigating new solvents, in particular for cellulose, chitin/chitosan, and starch. This overview focuses on recent advances in the dissolution and derivatization of these
[...] Read more.
Biopolymers and their derivatives are being actively investigated as substitutes for petroleum-based polymers. This has generated an intense interest in investigating new solvents, in particular for cellulose, chitin/chitosan, and starch. This overview focuses on recent advances in the dissolution and derivatization of these polysaccharides in solutions of strong electrolytes in dipolar aprotic solvents. A brief description of the molecular structures of these biopolymers is given, with emphases on the properties that are relevant to derivatization, namely crystallinity and accessibility. The mechanism of cellulose dissolution is then discussed, followed by a description of the strategies employed for the synthesis of cellulose derivatives (carboxylic acid esters, and ethers) under homogeneous reaction conditions. The same sequence of presentation has been followed for chitin/chitosan and starch. Future perspectives for this subject are summarized, in particular with regard to compliance with the principles of green chemistry. Full article
(This article belongs to the Special Issue Advances in Carbohydrate Chemistry 2012)
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