[Structural study of bergenan, a pectin from Bergenia crassifolia].

A pectin polysaccharide named bergenan was isolated from the freshly collected leaves of the leather bergenia Bergenia crassifolia by extraction with an aqueous solution of ammonium oxalate. The main component of its carbohydrate chain was shown to be the residues of D-galacturonic acid (about 80%). In addition, the polysaccharide contains residues of galactose, arabinose, and rhamnose; their total content is less than 15%. It was shown that the bergenan samples from bergenia leaves collected at different vegetation periods (from July to September) do not substantially differ either in monosaccharide composition or in the viscosity of aqueous solutions they form. The results of enzymatic hydrolysis by alpha-1,4-galacturonase (pectinase), partial acidic hydrolysis, NMR spectroscopy, and methylation with subsequent analysis of the results by GC-MS indicate that the bergenan macromolecule contains the regions of a linear alpha--1,4-D-galactopyranosyluronan and rhamnogalacturonan-I (RG-1). Galacturonan responds for a greater part of the macromolecule. A considerable amount of its constituent galacturonic acid residues are present as methyl esters. The side chains in RG-I are attached to the rhamnopyranose residues of the main carbohydrate chain by 1,4-link and are composed of the residues of terminal arabinofuranose and galactopyranose, 1,5-linked (-arabinofuranose, and 1,4-and 1,6-linked beta-galactopyranose. The branching points of the side chains of the RG-I molecule are 3,4- and 3,6-di-O-substituted galactose residues.

Stabilizing effect of Silene pectin polysaccharide on electrical activity of the sinoatrial area in frog heart.

Silenan, a pectin polysaccharide from common catchfly (Silene vulgaris), corrects disorders in the conduction of action potentials between cells of the sinoatrial area of frog heart forming a functional syncytium. Recovery of action potential conduction in the sinoatrial cells was recorded in long-term experiments (>8 h). The effect of silenan manifested mainly against the background of arrhythmic generation and impaired propagation of action potentials.

Structural studies of arabinogalactan and pectin from Silene vulgaris (M.) G. Callus.

Arabinogalactan and pectin (named silenan) were isolated from Silene vulgaris (M.) G. callus. Fractionation by ion-exchange chromatography on DEAE-cellulose and digestion with pectinase demonstrated that silenan from S. vulgaris callus (80% of D-galacturonic acid) and silenan from the aerial part of the campion S. vulgaris are similar: both pectins contain a high quantity of homogalacturonan segments. The NMR spectral data and mass spectrometry of the purified polysaccharide and its fragment obtained by Smith degradation confirmed that the core of the arabinogalactan consisted of the different segments of beta-1,3-D-galactopyranan. Some of the beta-galactopyranose residues of the backbone are branched at O-6. The side chains of the arabinogalactan were shown to contain residues of terminal and 3-O-substituted beta-galactopyranose, terminal alpha-arabinofuranose and alpha-rhamnopyranose, and 2-O-substituted alpha-rhamnopyranose. The alpha-rhamnopyranose residues in the sugar chain appeared to be 2-O-glycosylated by the beta-1,4-D-galactopyranosyl uronic acid residues.

Branching of the galacturonan backbone of comaruman, a pectin from the marsh cinquefoil Comarum palustre L.

Galacturonan, the main constituent of the backbone (core) of the comaruman macromolecule, a pectin from the marsh cinquefoil Comarum palustre L., was obtained on partial acid hydrolysis of the pectin. Using atomic force microscopy and methylation analysis of the galacturonan, the backbone of the comaruman macromolecule was shown to contain branches as side chains consisting of alpha-1,4-linked residues of D-galactopyranosyl uronic acid attached to the 2- and 3-positions of the galacturonic acid residues of the core, in addition to linear regions of alpha-1,4-D-galacturonan. A few side chains appear to attach to 2,3-positions of the D-galacturonic acid residues.

Structural studies on pectin from marsh cinquefoil Comarum palustre L.

Pectin with [alpha]D(20) +192 degrees (c 0.1; water), named comaruman, was isolated from marsh cinquefoil Comarum palustre L., which is widespread in the European North. The sugar chain of comaruman contains residues of D-galacturonic acid (64%), D-galactose (13%), L-rhamnose (12%), L-arabinose (6%), and trace amounts of xylose and glucose. Partial acid hydrolysis and digestion with pectinase demonstrated that comaruman composed of the backbone comprised regions of linear alpha-1,4-D-galactopyranosyl uronan interconnected by numerous residues of alpha-1,2-L-rhamnopyranose. In addition to the backbone (core of the macromolecule), ramified regions are involved in comaruman and comprise alpha-2,4-L-rhamno-alpha-4-D-galacturonan with side chains consisting mainly of beta-1,4-linked residues of D-galactopyranose. The ramified region contains additionally residues of 5-O-substituted arabinofuranose and 3- and 6-O-substituted galactopyranose. The present 3,4- and 4,6-di-O-substituted residues of galactopyranose appear to be branching points of the side chains. Some galactopyranose residues were found to occupy the terminal positions of the side chains or appeared to be single sugar residues attached to the side chains. Methylation analysis data indicated that comaruman contains residues of terminal, 3- and 3,4-di-O-substituted galactopyranosyl uronic acid, which appeared to be constituents of the side chains, and the latter represented additionally branching points of the backbone.

Structure of silenan, a pectic polysaccharide from Campion Silene vulgaris (Moench) Garcke.

A pectic polysaccharide named silenan, [alpha]D20 +148.6 degrees (c 0.1; H2O), was isolated earlier from the aerial part of campion, Silene vulgaris (Moench) Garcke. Silenan has been shown to contain homogalacturonan segments as "smooth regions" and rhamnogalacturonan fragments as "hairy regions". The present study reveals a generalization of structural features of silenan. Silenan was subjected to enzymic digestion with pectinase, to Smith degradation, and to lithium-degradation to determine the conforming poly- and oligosaccharide fragments of "hairy regions" of silenan. The NMR-spectral data and mass-spectrometry confirmed that the core of the ramified region of silenan consisted of residues of alpha-rhamnopyranose 2-O-glycosylated with the residues of alpha-1,4-D-galactopyranosyl uronic acid. The part of the alpha-rhamnopyranose residues of the backbone are branched at O-4. On the basis of the data, the hairy regions of silenan proved to contain mainly linear chains of beta-1,3-, beta-1,4-, and beta-1,6-galactopyranan and alpha-1,5-arabinofuranan. The side chains of the ramified region were shown to have branching points represented 2,3-, 3,6-, 4,6-di-O-substituted beta-galactopyranose residues.

[Isolation and structural study of polysaccharides from campion Silene vulgaris]. / Vydelenie i issledovanie stroeniia polisakharidov iz smolevki obyknovennoi Silene vulgaris.

Silenan SV, a pectic polysaccharide, was isolated from the aerial part of Silene vulgaris (Moench) Garke (Oberna behen (L.) Ikonn.), widespread through the European North of Russia. The polysaccharide was found to contain residues of galacturonic acid (63%), arabinose, galactose, and rhamnose as the main constituents. The results of a partial acidic hydrolysis, pectinase digestion, and NMR studies of silenan SV indicated that its molecule contains a linear alpha-1,4-D-galacturonan backbone and ramified regions. The core of the ramified regions is composed of residues of alpha-1,4-D-galacturonic acid along with 2-substituted alpha-rhamnopyranose residues. The NMR data showed that the silenan SV side chains are composed of the blocks built from the terminal alpha-1,5-linked arabinofuranose and beta-1,4-linked galactopyranose residues; these most likely are the side chains of rhamnogalacturonan, characteristic of other pectic polysaccharides. The nonreducing ends of these side chains contain alpha-arabinofuranose residues.

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.