Application of novel analytical ultracentrifuge analysis to solutions of fungal mannans.

Polysaccharides, the most abundant biopolymers, are required for a host of activities in lower organisms, animals, and plants. Their solution characterization is challenging due to their complex shape, heterogeneity, and size. Here, recently developed data analysis approaches were applied for traditional sedimentation equilibrium and velocity methods in order to investigate the molar mass distribution(s) of a subtype of polysaccharide, namely, mannans from four Candida spp.

The role of the glucuronoxylan carboxyl groups in the action of endoxylanases of three glycoside hydrolase families: A study with two substrate mutants.

Background: Bacterial appendage-dependent GH30 glucuronoxylan hydrolases recognize the substrate through an ionic interaction of a conserved positively charged arginine with the carboxyl group of 4-O-methyl-d-glucuronic acid. One of the options to verify this interaction is preparation of enzyme mutants. An alternative approach is a chemical modification of the substrate, glucuronoxylan, in which the free carboxyl group in all residues of MeGlcA is eliminated.

Bioactive hemicelluloses alkali-extracted from Fallopia sachalinensis leaves.

Fallopia sachalinensis, regarded as an invasive plant in Europe and designated for disposal, is traditionally used in Japan and China as herbal medicine. Attempted for valorization of the leaves, this paper reports on two protein-free polysaccharide fractions, a neutral (FS-5A) and an acidic (FS-5B) one, obtained via alkali extraction and consecutive purification. Both fractions were characterized by chemical, molecular, structural and bioactive properties.

Non-cellulosic polysaccharides from the leaves of small balsam (Impatiens parviflora DC.).

The leaves of the annual plant Impatiens parviflora DC., a herbal medicine in Asian countries and invasive in managed forests and natural environments in Central Europe, have the potential as a source of bioactive phenolic compounds and polysaccharides. Extractives accounted for ∼22% of the leaves, whereby, the methanolic extract contains mainly caffeic acid, ferulic acid, kaempferol, and quercetin derivatives, and 1,2,4-trihydroxynaphthalene-1-O-glucoside.

Structural diversity of pectins isolated from the Styrian oil-pumpkin (Cucurbita pepo var. styriaca) fruit.

To evaluate the seeded fruit biomass of the Styrian oil-pumpkin in view of its pectin component, a series of acidic polysaccharides were isolated by a six-step sequential extraction using hot water, EDTA, dilute HCl (twice) and dilute and stronger NaOH solutions. Chemical, physicochemical and spectroscopy analyses revealed that the first four fractions comprised partially methyl-esterified and acetylated pectins with varying proportions of rhamnogalacturonan regions ramified with galactose- and arabinose-containing side chains and showed considerable polymolecularity. The alkali-extracted polysaccharides contained lower amounts of pectins with homogalacturonan and arabinose-rich rhamnogalacturonan regions next to hemicelluloses prevailing in the last polysaccharide.

Structural features of two heteroxylan polysaccharide fractions from wheat bran with anti-complementary and antioxidant activities.

Wheat bran is a rich source of bioactive substances ascribed to its arabinoxylan component. Two water-soluble arabinoxylans were sequentially extracted from wheat bran. WB1, released during enzymatic digestion of starch and protein, contained medium-branched arabinoxylan (A/X=0.

Suppressive effect of pectic polysaccharides from Cucurbita pepo L. var. Styriaca on citric acid-induced cough reflex in guinea pigs.

Several water-soluble pectic polysaccharides were isolated from the pumpkin fruit biomass and characterized by composition, structural features and molecular properties. The pectic polysaccharides were tested for antitussive activity by studying the effects of citric acid-induced cough reflex in guinea pigs and reactivity of the airway smooth muscle in vivo conditions in comparison to the narcotic drug codeine. Oral administration of all pectic polysaccharides from pumpkin inhibited the number of coughs induced by citric acid in guinea pigs, but to various extents.

The pharmacological activity of wheat bran polysaccharides.

(Glucurono)arabinoxylans were extracted from the wheat bran with acetate buffer in the first step (WBH1) and with dilute alkali in the second step (WBH2). In both samples xylose and arabinose dominated, accompanied with smaller amounts of galactose, glucose, mannose and uronic acids mainly in WBH1. WBH1 was free of protein and with low content of phenolic compounds.

Production, refining, structural characterization and fermentability of rice husk xylooligosaccharides.

Oligosaccharides produced by hydrothermal processing of rice husks (xylooligosaccharides and glucooligosaccharides) were refined by membrane processing (operating in diafiltration and concentration modes), subjected to xylanase treatment to reduce the average molar mass, and subjected to further purification by ultrafiltration (operating in concentration mode) and ion exchange. The purified products were assayed for composition, molar mass distribution and structural characterization by HPLC, HPAEC-PAD, HPSEC, MALDI-TOF-MS and NMR ((1)H and (13)C). The fermentability of the purified product by fecal inocula was assessed on the basis of the time courses of pH and oligosaccharide concentrations.

Effect of microwave irradiation on the molecular and structural properties of hyaluronan.

Hyaluronan (Na(+) salt of hyaluronic acid, HA) was extensively depolymerised by HCl-catalyzed hydrolysis at pH 3 for up to 500min under temperature-controlled microwave irradiation. The effects of microwave heating on the hydrodynamic properties of the polysaccharide were determined by SEC-MALLS and viscometry. The weight-average molecular mass (Mw) of HA decreased from 1.

Comparison of conventional and ultrasound-assisted extraction of phenolics-rich heteroxylans from wheat bran.

Various two-step extraction procedures with and without a short application of ultrasound in the first step at various reaction conditions (extracting agent, temperature and time), and constant conditions in the second step (5% NaOH, room temperature, 60 min) were used to isolate the hemicellulose component of industrial wheat bran. The polysaccharides recovered from the extracts were characterised by yield, chemical composition and radical scavenging activity. Similar total yields of polysaccharides were achieved by a short ultrasound-assisted extraction (up to 10 min) in the first step using 0.

In vitro cytostatic and immunomodulatory properties of the medicinal mushroom Lentinula edodes.

Lentinula edodes, known as "shiitake" is one of the widely used medicinal mushrooms in the Orient. Antitumour activity of extracts of this mushroom has been widely demonstrated in animals and humans. However, this activity was shown to be host mediated and not by direct cytotoxic activity to cancer cells.

Norway spruce galactoglucomannans exhibiting immunomodulating and radical-scavenging activities.

Wood-derived naturally acetylated galactoglucomannans (AcGGM) can be recovered even in ton-scale at mechanical pulp mills using spruce as raw material. These cell wall polysaccharides have a great potential as hydrocolloids and bioactive polymers in food and pharmaceutical applications, or as starting material for production of functional polymers. The immunostimulatory activity of both AcGGM and its deacetylated form (GGM) was now in vitro tested.

Weak self-association in a carbohydrate system.

The physiological importance of weak interactions between biological macromolecules (molar dissociation constants >10 microM) is now well recognized, particularly with regard to cell adhesion and immunological phenomena, and many weak interactions have been measured for proteins. The concomitant importance of carbohydrate-carbohydrate interactions has also been identified, although no weak interaction between pure carbohydrate systems has ever been measured. We now demonstrate for the first time to our knowledge using a powerful probe for weak interactions--sedimentation velocity in the analytical ultracentrifuge--that at least some carbohydrates (from the class of polysaccharides known as heteroxylans and demonstrated here to be biologically active) can show well-defined weak self-interactions of the "monomer-dimer" type frequently found in protein systems.

Almond shell xylo-oligosaccharides exhibiting immunostimulatory activity.

Partially O-acetylated xylo-oligosaccharides (DXO) isolated from almond shells by autohydrolysis as well as their de-acetylated form (DeXO) were subjected to chemical, molecular, and structural analyses. They represent a mixture of neutral and acidic oligomers and low-molecular weight polymers related to (4-O-methyl-D-glucurono)-D-xylan. DXO and DeXO showed direct mitogenic activity and enhancement of the T-mitogen-induced proliferation of rat thymocytes, indicating the immunostimulatory potential of the almond shell xylo-oligosaccharides.

Effect of salt stress on the production and properties of extracellular polysaccharides produced by Cryptococcus laurentii.

The composition, main structural features and molecular properties of exopolysaccharides (EP) produced by Cryptococcus laurentii var. laurentii CCY 17-3-16 under optimal (EPo) and NaCI-stress conditions (EPs) as well as their subfractions isolated by gel chromatography were studied using chemical, FT-IR and NMR spectroscopy methods. The results showed that under stress conditions the yeast produced EP with a lower content of protein and phosphorus.

Xyloglucan degradation using different radiation sources: a comparative study.

Tamarind seed xyloglucan was subjected to different radiation sources-ultrasound, gamma-radiation, and microwave heating, and the effects of these energies upon its molecular and structural properties were characterised by gel permeation chromatography, viscometry, sugar analysis, FT-IR and NMR spectroscopic techniques. In dependence on the degradation methods and experimental conditions used, the decrease of the relative molecular mass (RMM) was accompanied with alteration of the primary structure. Depolymerisation by ultrasound at a frequency of 20 kHz yielded after 120 min products with RMM of about 131 x 10(3) without significant alteration of the primary structure of the polysaccharide.

A biologically active fructan from the roots of Arctium lappa L., var. Herkules.

From the roots of Arctium lappa L., var. Herkules a low-molecular-weight fructofuranan of the inulin-type has been isolated by water extraction and ethanol precipitation, followed by ion-exchange chromatography and gel filtration of the crude precipitate.

Characterization of immunomodulatory polysaccharides from Salvia officinalis L.

Crude polysaccharide fractions, rich mainly in arabinogalactans (A), pectin (B) and glucuronoxylan-related polymers (D), have been obtained from aerial parts of sage (Salvia officinalis L.) by sequential extraction with various reagents. Arabinogalactans displayed on HPLC a dominance of lower molecular-mass polymers (MW < 10,000), while pectin and glucuronoxylan-related polysaccharides showed predominance of polymers with MW > 50,000.

Ultrasonic extraction of plant materials--investigation of hemicellulose release from buckwheat hulls.

Various one- and two-step extraction procedures with and without a short application of ultrasound at the beginning of the extraction were used to examine the effect of sonication on the extractibility of the hemicellulose components of buckwheat hulls. The polysaccharides recovered from the extracts were characterised by yield as well as composition determined by chemical methods and spectroscopic techniques. They comprised a complex of glucuronoxylan and co-extracted amylose-rich starch in various proportions contaminated with other cell wall components (protein, pectic polysaccharides).

Mitogenic and comitogenic activities of polysaccharides from some European herbaceous plants.

From the leaves of Plantago lanceolata, the green parts of Rudbeckia fulgida, the aerial parts of Salvia officinalis and the roots of Valeriana officinalis, crude polysaccharides have been isolated by extraction with water and further purified and fractionated by various techniques. The water-soluble polysaccharides obtained were examined for their immunomodulatory activities using the in vitro mitogenic and comitogenic rat thymocyte tests. The results indicate that in spite of the considerable differences in chemical composition and structural properties, the tested polysaccharides exhibited similar significant immunomodulatory properties with a particularly high adjuvans activity in the case of the Rudbeckia and Salvia polysaccharides.

Effect of ultrasound on the extractibility of corn bran hemicelluloses.

Various two-step extraction procedures with and without a short application of ultrasound in the first step were used to examine the effect of sonication on the extractibility and properties of the non-cellulose components of industrial corn bran (CB). The polysaccharides recovered from the extracts of the first (FI) and second (FII) extraction step were characterised by yield and composition. Using water as extractant in the first step, similar yields of total extracted polysaccharides (FI + FII) were obtained by the short sonication treatment when compared to the classical procedures using H2O2-containing alkaline media in the first step.

Immunomodulatory activity of acidic xylans in relation to their structural and molecular properties.

The structure/function relationship of two acidic heteroxylan types, the arabino-(glucurono)xylan from corn cobs (AGX) and 4-O-methylglucuronoxylans (GXs) from beechwood and three medicinal herbs (Rudbeckia, Altheae, and Mahonia), has been studied. The effect of the molecular mass of AGX, as well as the content and distribution of the 4-O-methylglucuronic acid side chains in GXs on the immunological activity of these xylans was characterized by their biological response in the mitogenic and comitogenic thymocyte in vitro tests. Depolymerization of AGX by ultrasonication resulted in unequivocal decrease of the immunomodulatory activity, whereas already a short treatment by endo-beta-1,4-xylanase brought about a significant increase in its activity when applied in the highest dose.

Ultrasound-assisted extraction of water-soluble polysaccharides from the roots of valerian (Valeriana officinalis L.).

The insoluble plant residues, obtained after preparation of medicinal tinctures from the roots of valerian (Valeriana officinalis L.) by classical and ultrasound-assisted extraction with aqueous ethanol in a pilot plant, were subsequently treated with hot water to isolate the accessible polysaccharide cell wall components. At almost equal amounts of the hot-water extractable material, the yields of the recovered polysaccharides were lower in the ultrasonical experiment.

Comparison of classical and ultrasound-assisted extraction of polysaccharides from Salvia officinalis L.

After preparation of medicine tinctures from the herbal plant Salvia officinalis by classical and ultrasound-assisted extraction with aqueous ethanol, the insoluble plant residues were subsequently treated with hot water and dilute alkali to isolate polysaccharide cell wall components. The yields of the hot water extract as well as total extracted polysaccharides were higher in the case of the ultrasound-treated plant in both laboratory and pilot plant experiments. The water-extractable polysaccharide fractions, in all cases, contained glucose, galactose and arabinose as main sugar components, whereas the alkali-extractable fractions were rich in xylans.