Polysaccharide composition ofPolygonum aviculare

A polysaccharide isolated from the epigeal parts ofPolygonum aviculare has been fractionated. It has been shown that the initial polysaccharide consists of at least four fractions differing in their monosaccharide compositions and physico-mechanical properties.     

Convergent synthesis of a common pentasaccharide-repeating unit corresponding to the O-specific polysaccharide of Escherichia coli O4:K3, O4:K6, and O4:K12

A convergent chemical synthesis of a pentasaccharide found in the O-specific polysaccharide of Escherichia coli O4:K3, O4:K6, and O4:K12 has been achieved in excellent yield. A [3+2] block synthetic strategy has been adopted to couple a disaccharide donor 11 with a trisaccharide acceptor 10 for the construction of the pentasaccharide derivative 12 which on deprotection furnished target pentasaccharide 1 as its 4-methoxyphenyl glycoside. Disaccharide thioglycoside donor 11 and trisaccharide acceptor 10 were prepared from suitably protected monosaccharide intermediates. Yields were excellent in all steps.     

Polysaccharide from the leaves ofPhytolacca americana

A polysaccharide has been isolated from the leaves ofPhytolacca americana and has been characterized. It has been established that it contains residues of galactose, arabinose, xylose, and rhamnose, in a ratio of 3:4:1:3 and also D-galacturonic acid (85–90%). The results obtained permit the polysaccharide to be assigned to the class of pectin substances.All-Union Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 166–169, March–April, 1982.     

Unwinding of ι-carrageenan double helix upon complex formation with polyethylaminophosphazene hydrochloride

The interaction of poly(ethylaminophosphazene) hydrochloride (M _SD = 3.2 × 10⁵) with potassium ι-carrageenan (M _w = 2.2 × 10⁵), which is a linear regular anionic polysaccharide, has been studied by high-sensitivity DSC at pH 3.8 in a 0.15 mol/l solution of KCl. The dependences of temperature, enthalpy, and the cooperativity parameter of the double helix-coil transition of polysaccharide on the concentration ratio of polyphosphazene and polysaccharide have been obtained. The presence of polyphosphazene has no effect on the temperature and cooperativity of transition, whereas the enthalpy of the transition decreases linearly with the content of polyphosphazene and turns to zero at a mass polymer-to-polysaccharide ratio of approximately 1: 1, which corresponds to the equivalent concentrations of polyphosphazene and polysaccharide with respect to charges. Our data indicate that the mixing of poly(ethylaminophosphazene) hydrochloride and potassium ι-carrageenan solutions gives rise to formation of the stoichiometric interpolyelectrolyte complex, in which the polysaccharide loses its ability to form double helix typical of ι-carrageenan in saline solution (0.15 M KCl).     

Carbohydrate-protein biopolymers fromPseudopterogorgia americana

A carbohydrate-protein biopolymer which has been called corallan has been isolated from the soft coralP. americana. It has been shown that corollan consists of a proteoglycan including a protein component and a polysaccharide component connected with one another by a fairly strong bond. The polysaccharide moiety is a sulfated glycuronoglycan containing residues of fucose, arabinose, galactose, glucose, and a uronic acid and, possibly, also of aminosugars.     

First synthesis of a pentasaccharide repeating unit of the O-antigenic polysaccharide from enterohaemorrhagic Escherichia coli O48:H21

A concise synthesis of a pentasaccharide as its 4-methoxyphenyl glycoside, found in the O-antigenic polysaccharide of enterohaemorrhagic Escherichia coli O48:H21 has been achieved for the first time in excellent yield. Most of the intermediate steps are high yielding and the stereooutcome of each glycosylation step was excellent. Stereoselective glycosylation and removal of the 4-methoxybenzyl group were achieved in one-pot by tuning the reaction conditions. A late-stage TEMPO-mediated oxidation strategy has been adopted for the oxidation of a primary hydroxyl group to carboxylic acid.     

Lipopolysaccharides fromMastigocladus laminosus

A lipopolysaccharide (LPS) has been isolated by phenol-water extraction from the cells of the blue-green algaMastigocladus laminosus. It has been shown that the LPS contains polysaccharide and lipid components. The polysaccharide component includes a rhamnan fragment constructed of β-1,3- and, possibly, -1,2-bound L-rhamnose residues. The lipid component is constructed of glucosamine, glucose, and fatty acid residues, among which palmitic acid predominates.     

The effect of Moringa oleifera polysaccharides on the regulation of glucocorticoid-induced femoral head necrosis: In vitro and in vivo

One of the common challenges in using glucocorticoid in the long term is the development of femoral head necrosis. To address this challenge, the use of glucocorticoid suppressors like plant polysaccharides has been considered. In this study, Moringa oleifera polysaccharide was isolated through hot water–ethanol precipitation method and purified by DEAE-Sepharose fast flow column. Then, they were characterized by FT-IR, NMR, methylation, and chromatography assays. The polysaccharide biocompatibility was investigated by MTT assay and its effect on osteoblasts was evaluated by controlling gene expression. Also, the effect of polysaccharide on dexamethasone-induced femoral head necrosis in rats was assessed by hydroxyproline, hexosamine and morphometric parameters. The results show that 2 Da molecular weight polysaccharide is mainly composed of Rha, Ara, Fru, Xyl, Man and Gal in the molar ratio of 1.7:2.1:3.4:5.9:5.8:1.3. Meanwhile, MTT results on osteoblasts cells showed polysaccharide biocompatibility, while significantly reducing the negative effects of glucocorticoid. Likewise, polysaccharide significantly reduced the levels of apoptosis and intracellular ROS of glucocorticoid-induced femoral necrosis. Moreover, the results of gene expression indicated a decrease in the expression of TNF-α and IL-6 genes using polysaccharide, which is very effective in preventing apoptotic activity. Also, Polysaccharide increased bone density, bone volume per tissue volume, trabecular thickness, and the hexosamine to hydroxyproline ratio in the rat serum in the presence of glucocorticoids, which are very effective in the process of femoral head necrosis. Furthermore, polysaccharide significantly increases the OCN, RUNX2 and COL-1 genes expression in cartilage tissue, which is in line with the result of morphometric parameters. Overall, this study suggests that the use of polysaccharide could result in the treatment of femoral head necrosis.     

Electrophoretic separation of nitrogen-containing drugs using silica capillaries modified with citrate-stabilized gold nanoparticles, 6,10-ionene, N-(3-sulfo,3-carboxy)-propionylchitosan and dextran sulfate

Gold nanoparticles have been widely applied in different fields of science over the last decade, e.g., in physicochemical separation methods. Two fused silica capillaries for capillary electrophoresis (CE) modified layer-by-layer with citrate-stabilized gold nanoparticles, 6,10-ionene, N-(3-sulfo,3-carboxy)-propionylchitosan (SCPC), and dextran sulfate (DS) were obtained and investigated. It has been found that the separation of the mixture of tetrahydrozoline, pindolol, terbutaline, nadolol, and hydroxyzine is fastest and most effective when the capillaries are modified with gold nanoparticles than with polysaccharide and polymers only. The most successful system for CE was obtained using DS as the polysaccharide. The enantiomers of tetrahydrozoline were separated using the capillaries modified with gold nanoparticles, 6,10-ionene, and dextran sulfate.     

Determination of molecular weights and monosaccharide compositions in Abelmoschus manihot polysaccharides

Abelmoschus manihot polysaccharide, AMP-1, AMP-2, AMP-3, and AMP-4, were purified from four kinds of Abelmoschus manihot gum (AMG). The molecular weights and monosaccharide compositions of AMP-1, AMP-2, AMP-3 and AMP-4 were characterized by gel permeation chromatography, Fourier transform-infrared spectroscopy and high performance anion-exchange chromatography with pulsed amperometric detection. Results indicated that the molecular weights of AMP-1, AMP-2, AMP-3, and AMP-4 were approximately 3.91 × 10³, 5.36 × 10⁵, 3.87 × 10³, and 5.12 × 10⁵ Da, respectively. The Abelmoschus manihot polysaccharide was mainly composed of galactose, glucose and mannose with the molar ratios at 0.29: 1.00: 0.41 (AMP-1), 0.56: 0.13: 1.00 (AMP-2), 0.10: 1.00: 0.11 (AMP-3) and 0.55: 0.17: 1.00 (AMP-4), respectively.     

Extracellular polysaccharides produced by acapsular mutant of Cryptococcus laurentii

Heterogeneous extracellular polysaccharide galactoxylomannan has been isolated from the culture medium of the acapsulated mutant Cryptococcus laurentii 17-3-6 as the main extracellular polysaccharide (90%). Size-exclusion chromatography of precipitated polysaccharides afforded two molecular fractions with molecular mass 75 kDa and 20 kDa. Mannose, galactose, glucose, and xylose ratios were 1.00: 1.16: 0.04: 0.88 and 1.00: 0.25: 0.07: 0.24, respectively.     

Dynamic Changes in Xylanases and β-1,4-Endoglucanases Secreted by Aspergillus niger An-76 in Response to Hydrolysates of Lignocellulose Polysaccharide

Aspergillus niger is an effective secretor of glycoside hydrolases that facilitate the saprophytic lifestyle of the fungus by degrading plant cell wall polysaccharides. In the present study, a series of dynamic zymography assays were applied to quantify the secreted glycoside hydrolases of A. niger cultured in media containing different carbon sources. Differences in the diversity and concentrations of polysaccharide hydrolysates dynamically regulated the secretion of glycoside hydrolases. The secretion of β-1,4-endoglucanase isozymes was observed to lag at least 24 h behind, rather than coincide with, the secretion of xylanase isozymes. Low concentrations of xylose could induce many endoxylanases (such as Xyn1/XynA, Xyn2, and Xyn3/XynB). High concentrations of xylose could sustain the induction of Xyn2 and Xyn3/XynB but repress Xyn1/XynA (GH10 endoxylanase), which has a broad substrate specificity, and also triggers the low-level secretion of Egl3/EglA, which also has a broad substrate specificity. Mixed polysaccharide hydrolysates sustained the induction of Egl1, whereas the other β-1,4-endoglucanases were sustainably induced by the specific polysaccharide hydrolysates released during the hydrolysis process (such as Egl2 and Egl4). These results indicate that the secretion of glycoside hydrolases may be specifically regulated by the production of polysaccharide hydrolysates released during the process of biomass degradation.     

The rheological properties of gelatin gels containing κ-carrageenan. The role of polysaccharide

The influence of an anionic polysaccharide, κ-carrageenan, on the rheological properties of low-concentration (1.0 wt %) gelatin gels has been studied in a wide range of low polysaccharide concentrations (1 × 10^?3–5 × 10^?1 wt %) at a temperature of 14.0°C and pH values slightly higher than the isoelectric point of gelatin. The parameters characterizing the rheological properties of the gels are governed by the mass ratio between the polysaccharide and gelatin, which are able to form (bio)polyelectrolyte complexes in aqueous systems. There is a critical κ-carrageenan-to-gelatin mass ratio Z ? 0.1, above which the yield stress of the gels and their effective viscosit at stresses exceeding the yield point drastically rise. The increase in these rheological parameters correlates with a growth in the particle size of κ-carrageenan-gelatin polyelectrolyte complexes, which are formed in the aqueous bulk phase at an elevated temperature and precede gelation.     

Preparation of a growth-promoting substance, lepidimoic acid, from okra pectic polysaccharide

Lepidimoic acid, a 1,2-cis-linked disaccharide, is an interesting plant growth-promoting substance and has been synthesized from d-glucose and l-rhamnose by Kosemura et al., 1993. Fry et al., 1993, in view of the biosynthetic origin, suggested that it could be produced by the cleavage of a pectic polysaccharide such as rhamnogalacturonan. In this study lepidimoic acid was prepared from okra (Hibiscus esculentus L.) pectic polysaccharide in a passable yield by sequential decomposition reactions. The plant growth-promoting activity of the prepared lepidimoic acid was confirmed.     

A general method for the synthesis of oligosaccharides consisting of α-(1→2)- and α-(1→3)-linked rhamnan backbones and GlcNAc side chains

A general method has been developed for the synthesis of oligosaccharides consisting of (1→2)- and (1→3)-linked rhamnans with GlcNAc side chains. As examples, highly effective and convergent syntheses of two decasaccharides in the O polysaccharide moiety of the lipopolysaccharide of the phytopathogenic bacterium Pseudomonas syringae pv. ribicola NCPPB 1010 were achieved. The two decasaccharides consist of O polysaccharide repeating units I+II and II+I, respectively. Allyl 3-O-acetyl-4-O-benzoyl-α-l-rhamnopyranoside, allyl 2-O-benzoyl-3-O-chloroacetyl-α-l-rhamnopyranoside, 2,4-di-O-benzoyl-3-O-chloroacetyl-α-l-rhamnopyranosyl trichloroacetimidate, and 3-O-acetyl-2,4-di-O-benzoyl-α-l-rhamnopyranosyl trichloroacetimidate, which were obtained by highly regioselective 3-O-acylations, were used as the key synthons to obtain the required α-(1→2)- and α-(1→3)-linked rhamnoocta saccharide acceptors with 3³- and 3⁷-free hydroxyl groups. Therefore, several disaccharides were synthesized, from which tetrasaccharides and hexasaccharides were then synthesized. Coupling of the hexasaccharide donors with the disaccharide acceptors gave the octasaccharide acceptors. Finally, the coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl trichloroacetimidate with the octasaccharide acceptors, followed by deprotection, afforded the two target decasaccharides. A repeating hexasaccharide unit of the cell wall polysaccharide of β-hemolytic Streptococci Group A was also synthesized in a similar way.     

A polysaccharide from the pith of the stems ofAlthea flavovirens

It has been established that a polysaccharide from the pith of the stems ofAlthea flavovirens Boiss et Buhse growing in Azerbaidzhan (environs of the village of Dzhul'fy) has a branched molecule consisting of residues of ribose, rhamnose, glucose, and glucuronic and galacturonic acids (3:6:3:7:2). Among the products of the methylation of the polysaccharide reduced at the carboxy groups the following sugar derivatives have been identified: 2,3,4-tri-O-methyl-L-rhamnose, 3,4-di-O-methyl-L-rhamnose, 2,3,4,6-tetra-O-methyl-D-glucose, and 2,3,6-tri-O-methyl-D-glucose and 2,3,6-tri-O-methyl-D-galactose (unresolved mixture), and also 2,6-di-O-methyl-D-glucose (2:10:24:7:2).V. L. Komarov Botanical Institute, Academy of Sciences of the USSR, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 29–33, January–February, 1980.     

Graft polymerization of acrylamide on chitosan: Copolymer structure and properties

Graft copolymers have been prepared through the free-radical polymerization of acrylamide in water-acetic acid solutions of chitosan in the presence of ammonium persulfate as an initiator. The effect of temperature, pH of a medium, and concentrations of initiator, chitosan, and acrylamide on the grafting kinetics and efficiency has been established. The local concentration of acrylamide in the reaction zone increases due to intermolecular hydrogen bonding between polysaccharide and monomer molecules. Copolymer films are characterized by better mechanical properties compared to those of polysaccharide. Hydrogels with good viscoelastic properties have been obtained when grafting was performed in the presence of N,N-methylenebisacrylamide as a crosslinking agent.     

Chemical investigation of the polysaccharides of the leaves ofPlantago major L.

Summary 1. A polysaccharide has been isolated from the leaves ofPlantage major L. and its monosaccharide composition has been studied.2. It has been established that the polysaccharide investigated contains D-galacturonic acid, D-galactose, D-glucose, D-xylose, L-rhamnose, L-arabinose, a partially methylated galactose, and two unidentified monosaccharides.3. The high content of galacturonic residues (68%) in the polysaccharide enables it to be classified as a pectin.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 5, pp. 297–302, 1965     

The Interaction of Polysaccharide from Auricularia polytricha with Quantum Dots and the Protection of Plasmid DNA from Damage

As a kind of folk medicine, edible mushrooms are known to be of medicinal characteristics, for example antitumor activity. However, the mechanism is not clear. In this study, the fluorescence (FL) spectroscopy was used to study the binding reactions of polysaccharide extracted from Auricularia polytricha with quantum dots (QDs). The modified Stern–Volmer quenching constant at different temperatures and corresponding thermodynamic parameters were calculated (?G?<?0, ?H?<?0, and ?S?<?0). The results show that the quenching constant is inversely correlated with temperature. It indicates that the quenching mechanism is the static quenching in nature rather than dynamic quenching. The negative values of free energy (?G?<?0) suggest that the binding process is spontaneous; ?H?<?0 and ?S?<?0 suggest that the binding of polysaccharide to QDs is enthalpy-driven. QDs were found to damage the plasmid DNA according to atomic force microscopy images. DNA damage is the important factor to induce tumor. Many chemical substances can induce tumor, which has been proved by modern medical science. In the presence of polysaccharide from A. polytricha, however, DNA was protected from damage due to polysaccharide winding around QDs, which is the basis for the bioeffect of polysaccharides. This study helps to understand that antitumor activity of edible mushrooms is attributed to protection of DNA from damage in the presence of harmful substances.     

Structural investigation of the lipopolysaccharide ofYersinia enterocolitica serovar 0:8

The lipopolysaccharide ofYersinia enterocolitica serovar 0:8 (strain 161) isolated from the microbial mass by aqueous-phenol extraction contains residues of L-fucose-6-deoxy-D-gulose, D-mannose, D-galactose, D-glucose, D- and L-glycero-D-mannoheptoses, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and 2-keto-3-deoxyoctonic acid (KDO). The polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide followed by gel filtration on Sephadex G-50. On the basis of the results of monosaccharide analysis, methylation, Smith degradation, and partial hydrolysis the following structure is suggested for the repeating unit of the O-specific polysaccharide of the LPS ofYersinia enterocolitica, serovar 0:8: