Yury S. Ovodov

Effects of polysaccharides from Silene vulgaris on phagocytes

The effects of the polysaccharides isolated from the intact plant (pectic polysaccharides P1, P2 and P3) and from the callus (acidic arabinogalactan C1 and pectin C2) of Silene vulgaris on phagocytic activity were studied in relation to an uptaking capacity and a myeloperoxidase activity of the peripheral human neutrophils and monocytes and rat peritoneal macrophages in vitro. Both intact plant and callus polysaccharides were shown to increase uptaking capacity of peripheral phagocytes. The callus acidic arabinogalactan C1 was only found to stimulate lysosomal activity of the peripheral phagocytes. Some polysaccharides studied were established to effect on peritoneal resident macrophages. Pectins P1, P3 and C2 failed to enhance myeloperoxidase activity of the macrophages in calcium-free solution, whereas the effect of callus arabinogalactan C1 was established to be independent of extracellular calcium. Polysaccharides studied failed to influence neither complement receptor CR3- nor scavenger receptor SR-mediated adhesion of the macrophages. The data obtained demonstrate that the intact S. vulgaris and its callus may be used as sources of immunoactive polysaccharides and that pectins and weakly acidic arabinogalactan seemed to stimulate macrophages through different mechanisms. Complement receptor type 3 and scavenger receptor failed to mediate the cell activation induced by plant polysaccharides.

Pectic polysaccharides of the fresh plum Prunus domestica L. isolated with a simulated gastric fluid and their anti-inflammatory and antioxidant activities

A pectic polysaccharide, designated as PD, was extracted from fresh plums (Prunus domestica L.) with a simulated gastric fluid. Galacturonan, which was partially substituted with methyl and O-acetyl ester groups, and rhamnogalacturonan were the main constituents of the linear regions of the sugar chains of PD. The ramified region contained mainly 1,4-linked β-d-galactopyranose residues and, to a lesser extent, 1,5-linked α-l-arabinofuranose residues. The separation of PD, by DEAE-cellulose column chromatography, yielded two pectic fractions: PD-1 and PD-2, eluted with 0.1 and 0.2 M NaCl, respectively. Enzymatic digestion of PD with 1,4-α-d-polygalacturonase yielded the fraction PD-E. The parent pectin PD and the PD-1 fraction were found to diminish the adhesion of peritoneal leukocytes at the concentrations of 0.05-1.0mg/ml. However, the PD-E fraction failed to have an effect on cell adhesion at the concentrations of 0.05-0.1mg/ml. PD, PD-1 and PD-E were found to inhibit the production of superoxide anion radicals by reducing xanthine oxidase activity by 38%, 97% and 47%, respectively. Therefore, the PD-1 fraction appeared to be an active fragment of pectic macromolecule isolated from fresh plum with a simulated gastric fluid.

New glycolipids (chitooligosaccharide derivatives) possessing immunostimulating and antitumor activities

New glycolipids, derived from chitooligosaccharides of dp 2-4 and containing both free and acylated amino groups, were synthesized. The structure of the key compounds (di-, tri-, and tetra-saccharides acylated with different fatty acids) were elucidated by 13C NMR spectroscopy. Only the amino group of the reducing end of the chitooligosaccharides was found to be acylated when equimolecular amounts of reagents were used. The compounds obtained were shown to possess a low toxicity and certain immunostimulatory and antitumor activities. An induction of interleukin-1 and tumor necrosis factor by the immunocompetent cells and an augmentation by 140-180% of the mean life of mice with the Erlich carcinoma were observed.

Structural studies of the pectic polysaccharide from Siberian fir (Abies sibirica Ledeb.).

The pectic polysaccharide named abienan AS-A was isolated from the wood greenery of Abies sibirica using dilute hydrochloric acid (pH 4.0) at 70°C. The structure of abienan AS-A was elucidated using sugar composition analysis, ion-exchange chromatography and partial acid hydrolysis followed by NMR spectroscopy. The linear region of abienan AS-A was shown to contain linear 1,4-α-D-galactopyranosyluronan partially substituted with methyl esters or 3-O-acetyl groups and rhamnogalacturonan blocks consisting of 1,4-α-D-galacturonan partially substituted with methyl ester groups and connected by 2-O-substituted α-rhamnopyranose residues. The branched region of abienan AS-A was found to be made of RG-I. The side chains of RG-I were shown to contain 1,4-β-galactan and branched arabinan. Some 4-O-substituted β-galactopyranose residues were shown to be attached to the 4-position of the 2-O-substituted α-rhamnopyranose residues of the RG-I backbone. The arabinan groups were made up of a 1,5-linked α-L-arabinofuranan backbone that was 3-O-, 2-O-, and 2,3-di-O-substituted with the terminal and 1,3-linked α-L-arabinofuranose residues.

Structure of the capsular polysaccharide from Alteromonas sp. CMM 155

Capsular polysaccharide (CPS) was obtained by water-saline extraction of the Alteromonas sp. CMM 155. On the basis of solvolysis with anhydrous HF and 1H- and 13C-NMR spectral data, including NOE experiments, it was concluded that the capsular polysaccharide had the following structure containing novel N-acyl-amino sugar and bacillosamine residues: --> 3)-alpha-D-GalpNAc-(1 --> 4)-alpha-L-GalApNAc(1 --> 3)- alpha-D-QuipNAc4NAc-(1 --> 3)-beta-D-Quip4NAlaAc-(1 -->

Structure of pectic polysaccharides isolated from onion Allium cepa L. using a simulated gastric medium and their effect on intestinal absorption

The polysaccharide fraction extracted with simulated gastric juice from onion bulbs contained a mixture of galactan with short-length sugar chains, pectic polysaccharides and evident content of proteinaceous material. Galacturonan and rhamnogalacturonan were the main constituents of the linear regions of the sugar chains of the pectic polysaccharides. The ramified regions included rhamnogalacturonan-I. NMR data revealed that the side chains of the ramified region contained mainly 1,4-linked β-D-galactopyranose residues and lesser content of 1,3-linked β-D-galactopyranose and 1,5-linked α-L-arabinofuranose residues. Furthermore, the proteinaceous material was determined to be partly linked to the sugar chains. The polysaccharide fraction was found to decrease absorption of ovalbumin (OVA) to the blood from the gut lumen. The serum OVA level was threefold lower in mice fed with OVA mixed with the onion pectins compared with the control group, which was administered OVA alone. Protein removal failed to abolish the inhibitory effect of the onion polysaccharides, confirming that the polysaccharide chains are the active component of onion gastric juice extract.

Swelling and morphology of calcium pectinate gel beads obtained from Silene vulgaris callus modified pectins.

The aim of this research is to investigate the swelling properties and morphology of the calcium pectinate gel (CaPG) beads made from pectins of campion callus cultured using various medium nutrients (carbon sources, concentration of sucrose, calcium and 2,4-dichlorophenoxyacetic acid (2,4-D)). Gelled spheres were prepared by ionotropic gelation. The mean diameter, total surface area and volume of the dried beads varied depending on the plant cell culture conditions. The swelling of dried CaPG beads in solutions with pH 2 and pH 4 was demonstrated to occur more slowly (within 4 or 24h) with increasing sucrose and calcium concentrations or in the absence of auxin. All beads swelled less when placed in acidic media (pH 2 and pH 4) and swelled most extensively in NaCl (pH 6). The surface morphology of the CaPG beads was demonstrated to depend on the presence of sugars, calcium and auxin in the plant cell culture medium used. The slow swelling of dried CaPG beads was apparently related to their grooved surfaces. An applied strategy involving changing the composition and concentration of media components altered the swelling behavior of the CaPG beads and enhanced the acid and water resistance of the resultant pectinate hydrogels in physiological environments. In particular, the swelling of Ca 4.5, 2,4-D0, Suc30 and Suc100 CaPG beads occurred more slowly.

Abrogation of the oral tolerance to ovalbumin in mice by citrus pectin

OBJECTIVE We studied the effects of dietary pectins (citrus pectin [CP] and apple pectin) on oral tolerance in mice. METHODS Pectins (1 mg/d) were administered orally for 2 wk. Tolerance was induced with 20 mg of ovalbumin (OVA). Levels of serum antibodies (immunoglobulin [Ig] G, IgG1, IgG2a, IgE) and delayed type hypersensitivity response determined in footpad tests were measured after subcutaneous injection of OVA with complete Freunds adjuvant. Concentrations of immunoreactive OVA in blood were measured by enzyme-linked immunosorbent assay after feeding the animals 20 mg of OVA. Adhesion and cytokine production (tumor necrosis factor-alpha, interferon-gamma) were measured in peritoneal macrophages. RESULTS Oral administration of CP was found to prevent the induction of immune hyporesponsiveness induced by OVA feeding. Animals fed OVA and CP were found to produce similar titers of antigen-specific serum IgG and levels of delayed type hypersensitivity response as those animals not fed OVA. CP increased levels of serum IgG1 and IgE. CP was found to enhance the penetration of immunogenic OVA into the serum. CP (1 mg/d) administered orally for 1 wk was also observed to enhance the adhesion and production of cytokines (tumor necrosis factor-alpha, interferon-gamma) in peritoneal macrophages. CONCLUSION CP administered orally was shown to inhibit oral tolerance. Enhancement of protein antigen penetration to the blood and activation of macrophages were found to precede the inhibitory effect and appeared to mediate it.

Immunomodulatory activity of polysaccharides isolated from Clerodendrum splendens: beneficial effects in experimental autoimmune encephalomyelitis.

BackgroundExtracts of leaves from Clerodendrum have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts.MethodsPolysaccharides from the leaves of Clerodendrum splendens were extracted and fractionated by ion exchange and size-exclusion chromatography. Molecular weight determination, sugar analysis, degree of methyl esterification, and other chemical characterization of the fractions were performed. Immunomodulatory activity of the fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO), cytokine production, and mitogen-activated protein kinase (MAPK) phosphorylation. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice, and severity of EAE was monitored in mice treated with intraperitoneal (i.p.) injections of the most active polysaccharide fraction. Lymph nodes (LN) and spleen were harvested, and levels of cytokines in supernatants from LN cells and splenocytes challenged with myelin oligodendrocyte glycoprotein peptide were determined.ResultsFractions containing type II arabinogalactan had potent immunomodulatory activity. Specifically, the high-molecular weight sub-fraction CSP-AU1 (average of 38.5 kDa) induced NO and cytokine [interleukin (IL)-1α, -1β, -6, -10, tumor necrosis factor (TNF; designated previously as TNF-α), and granulocyte macrophage-colony stimulating factor (GM-CSF)] production by human peripheral blood mononuclear cells (PBMCs) and monocyte/macrophages. CSP-AU1- induced secretion of TNF was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS, indicating a role for TLR4 signaling. Treatment with CSP-AU1 also induced phosphorylation of a number of MAPKs in human PBMC and activated AP-1/NF-κB. In vivo treatment of mice with CSP-AU1 and CSP-NU1 resulted in increased serum IL-6, IL-10, TNF, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α/CCL3, and MIP-1β/CCL4. CSP-AU1 treatment of mice with EAE (50 mg/kg, i.p., daily, 13 days) resulted in significantly reduced disease severity in this experimental model of multiple sclerosis. Levels of IL-13, TNF, interferon (IFN)-γ, IL-17, and GM-CSF were also significantly decreased, whereas transforming growth factor (TGF)-β was increased in LN cells from CSP-AU1-treated EAE mice.ConclusionsPolysaccharide CSP-AU1 is a potent natural innate immunomodulator with a broad spectrum of agonist activity in vitro and immunosupressive properties after chronic administration in vivo.

Changes in cell wall polysaccharides of Silene vulgaris callus during culture

In Silene vulgaris (M.) G. cell culture three growth phases were distinguished, namely, a lag phase, an exponential phase and a stationary phase. Pectin termed silenan and an acidic arabinogalactan were isolated as cell wall polysaccharides of S. vulgaris callus at the different growth phases during culture. Production of silenan as the galacturonan (or rhamnogalacturonan) core was observed at the beginning of the exponential phase and at the stationary phase of the callus growth. Arabinogalactan, containing the galacturonic acid residues, is formed at the exponential phase followed by attachment to the core of silenan in the middle of the exponential phase. The arabinogalactan constituent of silenan appeared to be destroyed gradually at the stationary growth phase. The monosaccharide compositions of silenan and arabinogalactan were determined at various phases of the callus growth. Silenan was found to be formed in maximum amounts at the exponential phase of the cell growth. Insignificant alterations of the yields of acidic arabinogalactan were found during culture while total productivity per litre of medium and rate of production per day of arabinogalactan were found to be maximal at the exponential phase of growth.