Glucopyranosyl Groups Research Articles

NMR-Based Elucidation of the Positional C6-O-Glucopyranosyl Substitution of Gomphrenin I Isolated from Basella alba Fruits

In this study, gomphrenin I (15S-betanidin-6-O-β-D- glucopyranoside), a betacyanin pigment, was isolated from Basella alba L. fruits, of which chemical structure has been definitively and unequivocally elucidated through in-depth NMR spectroscopic analyses. For the first time, by means of 13 C, selective TOCSY, HSQC and HMBC NMR, all carbon atoms of gomphrenin I were identified. Further based on NOESY-correlation spectral analysis, we demonstrated that a glucopyranosyl group as the linking moiety at the C-6 hydroxyl group of gomphrenin I. Positional C6 or C5 substitution of a glucopyranosyl moiety differentiates gomphrenin I from betanin, a common betacyanin pigment in sugar beets. We have also demonstrated that both glucopyranosyl and indole groups were present as composing structure of gomphrenin I.

Synthesis and enantiomeric recognition studies of a novel 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups

A novel optically active 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups was synthesized and its enantiomeric recognition properties were examined towards the enantiomers of tetrabutylammonium salts of chiral α-hydroxy and N-protected α-amino acids using UV–vis spectroscopy.

Bioconversion of ginsenoside Rc into Rd by a novel α-l-arabinofuranosidase, Abf22-3 from Leuconostoc sp. 22-3: cloning, expression, and enzyme characterization

A novel α-L-arabinofuranosidase (Abf22-3) that could biotransform ginsenoside Rc into Rd was obtained from the ginsenoside converting Leuconostoc sp. strain 22-3, isolated from the Korean fermented food kimchi. The gene, termed abf22-3, consisting of 1,527 bp and encoding a protein with a predicted molecular mass of 58,486 Da was cloned into the pMAL-c2x (TEV) vector. A BLAST search using the Abf22-3's amino acid sequence revealed significant homology to that of family 51 glycoside hydrolases. The over-expressed recombinant Abf22-3 in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinofuranoside moiety attached to the C-20 position of ginsenoside Rc under optimal conditions of pH 6.0 and 30 °C. This result indicated that Abf22-3 selectively converts ginsenoside Rc into Rd, but did not catalyze the hydrolysis of glucopyranosyl groups from Rc or other ginsenosides such as Rb1 and Rb2. Over-expressed recombinant enzymes were purified by two steps with amylose-affinity and DEAE-cellulose chromatography and then characterized. The kinetic parameters for α-L-arabinofuranosidase showed apparent Km and Vmax values of 0.95 ± 0.02 μM and 1.2 ± 0.1 μmol min(-1) mg of protein(-1) against p-nitrophenyl-α-L-arabinofuranoside, respectively. Using a purified MBP-Abf22-3 (10 μg/ml), 0.1 % of ginsenoside Rc was completely converted to ginsenoside Rd within 20 min.

Synthesis and G-quadruplex binding study of a novel full visible absorbing perylene diimide dye

Abstract A novel perylene diimide dye containing glucopyranosyl groups in 1- and 7-positions of the perylene ring has been synthesized and characterized to obtain highly efficient and stable photosensitized material in photodynamic therapy. Solvatochromic studies on this dye in solvents of different polarities have indicated that absorption bands of the dye cover the whole visible spectrum in more polar organic solvents. It shows absorption bands localized at 350–500 nm and 600–850 nm in benzonitrile giving a green color. Also, the dye has a wide absorption region which covers the wavelength between 400 and 800 nm in more polar solvents by changing the dye concentration in the solvents. Singlet oxygen generation efficiency and G-quadruplex binding affinity of the dye have been tested. Theoretical calculations through semi-empirical methods have been performed and a detailed spectroscopic assignment of the molecule has been also presented.

Chiral anion recognition by color change utilizing thiourea, azophenol, and glucopyranosyl groups

A new colorimetric anion sensor 1 was synthesized for the chiral recognition, which accommodates a combination of three different functional groups such as chromophore (azophenol dye), binding site (thiourea group), and chiral barrier (glucopyranosyl group). The colorimetric changes of host 1 with various α-amino carboxylates as well as chiral carboxylates such as naproxen were examined.

Anthracene Derivatives Bearing Thiourea and Glucopyranosyl Groups for the Highly Selective Chiral Recognition of Amino Acids: Opposite Chiral Selectivities from Similar Binding Units

Two new anthracene thiourea derivatives, 1 and 2, were investigated as fluorescent chemosensors for the chiral recognition of the two enantiomers of alpha-amino carboxylates. Especially, host 2 displayed K(L)/K(D) values as high as 10.4 with t-Boc alanine. Furthermore, the D/L selectivity of hosts 1 and 2 is opposite, even though both hosts bear the same glucopyranosyl units. These intriguing opposite D/L binding affinities by 1 and 2 were obtained without/with H-pi interaction between anthrancene moiety and the methyl groups, which were explained by extensive high-level theoretical investigations taking into account the dispersion energy as well as the 2D-NMR chemical shifts.

Ester Derivatives from Tannase-treated Prunioside A and Their Anti-inflammatory Activities

Prunioside A, isolated from the methanol extract of Spiraea prunifolia var. Simpliciflora's root, is composed of coumaroyl, monoterpene-type, and glucosyl units. The esterase activity of tannase was used to remove the p-coumaroyl and glucopyranosyl groups. The enzymatically hydrolyzed compound was reacted with various acyl chlorides to synthesize its ester derivatives, which showed the inhibitory effects on NO production in murine machrophage?like RAW 264.7 cells stimulated with lipopolysaccharide and interferon-γ.

Production of scleroglucan from Sclerotium rolfsii MTCC 2156

Scleroglucan, a neutral homopolysaccaride consisting of a linear chain of β- d-(1-3)-glucopyranosyl and β- d-(1-6)-glucopyranosyl groups, was produced by pure culture fermentation from Sclerotium rolfsii MTCC 2156 by submerged culture. Fermentation process was optimized in two steps. In the first step, one-factor-at-a-time method was used to investigate the effects of medium constituents such as carbon and nitrogen sources. In the second step, concentration of medium components was optimized using an L 16-orthogonal array method. In all, 10 different carbon sources and eight different nitrogen sources were evaluated. Maximum yield of 16.58 g/l was obtained in a medium containing sucrose as a carbon source and sodium nitrate and yeast extract as nitrogen source.

Synthesis of 2-(4-aminophenyl)ethyl [formula omitted] acid, a highly branched pentasaccharide corresponding to structures found in lipopolysaccharides from Moraxella catarrhalis

Syntheses of the pentasaccharide 2-(4-aminophenyl)ethyl 3- deoxy-5-O-(3,4,6- tri-O-β- d- glucopyranosyl-α- d-glucopyranosyl)-α- d-manno- oct-2- ulopyranosidonic acid and of the tetrasaccharide 3,4,6- tri-O-β- d- glucopyranosyl-α- d- glucopyranoside , both as its methyl and 2-(4-trifluoroacetamidophenyl)ethyl glycoside, are described. These oligosaccharides correspond to structures found in the lipopolysaccharide of Moraxella catarrhalis and were needed for biological experiments aimed at producing antibodies against the bacteria. The best way to introduce the glucopyranosyl groups into the 3-, 4-, and 6-positions of the branched target compounds was found to be a one-step reaction using a 3,4,6-triol as acceptor and 2,3,4,6- tetra-O- benzoyl- d-glucopyranosyl bromide as donor in a silver trifluoromethanesulfonate-promoted coupling. The spacer arm, necessary for the formation of immunoactive glycoconjugates, was introduced into the glucose moiety via a dimethyl(methylthio)sulfonium trifluoromethanesulfonate-promoted reaction using the ethyl thioglucoside as donor, whereas for Kdo, the acetylated glycal derivative, methyl 4,5,7,8- tetra-O- acetyl-2,6- anhydro-3- deoxy- d -manno- oct-2- enonate , was used as donor and phenylselenyl trifluoromethanesulfonate as a stereocontrolling promoter.

Electron impact mass spectra of permethylated disaccharide alditols

The electron impact mass spectra (EIMS) of 19 permethylated hexopyranosyl-hexitols, monodeuterated at C′-1, four partially trideuteriomethylated analogues, and some other permethylated hexopyranosides have been investigated. In the formation of the A 1 ion from the hexopyranosyl-hexitols, only a minor part is formed by direct cleavage between the glycosyl group and the “aglycon”. The major part is formed by elimination of neutral molecules from different primary ions resulting from cleavage between adjacent carbon atoms in the alditol residue. As a consequence of this facile elimination, these primary ions are not observed or are very weak. From a critical study of the mass spectra, diagnostic ions, from which the position of linkage to the alditol residue in these and related substances can be assigned, have been identified. From the relative intensities of the A 1, A 2, and A 3 ions, glucopyranosyl groups can be distinguished from manno- and galacto-pyranosyl groups.

The crystal structure of anhydrous α,α-trehalose at −150°

The crystal structure of α,α-trehalose (α- d-glucopyranosyl α- d-glucopyranoside), C 12H 22O 11, is monoclinic, P2 1, Z = 2, with unit cell dimensions at −150° [20°] of a = 12.971(5) [13.003(5)], b = 8.229(4) [8.252(4)], c = 6.789(3) [6.799(3)] Å, β = 98.12(4) [98.33(4)]. The crystal structure was solved by using MULTAN, and refined to R = 0.059, R w = 0.048 for 1564 intensities, measured with MoK α radiation. The molecular structure is very similar to that observed in the dihydrate crystals. It has approximate C 2 symmetry. Both glucopyranosyl groups are in the 4 C 1 conformation. The linkage torsion angles, O-5—C-1—O-1—C-1, are +60.8° and +60.1°. The primary alcohol groups are oriented gauche/gauche and gauche/trans, as in the dihydrate structure. A comparison of the cross-polarization, magic-angle-spinning (c.p.-m.a.s.), 13C-n.m.r. spectra for powders of the crystalline anhydrous and dihydrate forms shows differences in resonances assigned to C-1 and C-4 that would not be anticipated from the results of the crystal-structure analyses.

Preparation of copoly ( [formula omitted]) and its interaction with fibroblast cells

Copoly(α-amino acid)s consisting of γ-benzyl- l-glutamate and N 5-β- d-glucopyranosyl- l-glutamine were prepared by the reaction of copoly( l-glutamate) containing succinimide ester, which served as active site for the coupling reaction with β- d-glucopyranosylamine. The α-helical conformation of these copolymers became unstable in DMF as the content of glutamine derivative increased. A dry film made from this copolymer could take a full α-helical conformation even at such a high content as 80% of the glutamine derivative, but in a wet film this ordered structure was partially disrupted by hydration. The hydraulic permeability of this copoly(α-amino acid) was clearly dependent on the molar content of glucopyranosyl groups. The attachment of fibroblast cells to these hydrated copolymer films was effectively depressed in the presence of a serum-free medium. The cells attached to the substrate were spherical in shape.