Polysaccharide components of the seed-coat mucilage from hyptis suaveolens

The mucilage isolated from the seed coat of Hyptis suaveolens contains l-fucose, d-xylose, d-mannose, d-galactose, d-glucose and 4-O-methyl-d-glucuronic acid in the mol ratios 1.0:2.5:1.5:7.0:12.5:1.1. Fractionation of the mucilage with Fehling's solution gave a neutral and an acidic polysaccharide. The neutral polysaccharide appears to be homogeneous and is composed of d-mannose, d-galactose and d-glucose in the mol ratios 1.0:4.5:7.5. The acidic polysaccharide is composed of l-fucose, d-xylose and 4-O-methyl-d-glucuronic acid in the mol ratios 1.0:2.5:1.1. It is homogeneous on gel filtration, DEAE-cellulose chromatography, sedimentation analysis and electrophoresis.     

Structural studies of capsular polysaccharide of type XII Diplococcus pneumoniae

The capsular polysaccharide of Diplococcus pneumoniae Type XII contains residues of d-glucose and d-galactose in a molar ratio of 2:1. The methylated polysaccharide yielded upon hydrolysis 2,3,4,6-tetra- and 3,4,6-tri-O-methyl-d-glucose and 2,3,4,6-tetra-O-methyl-d-galactose as the only neutral methyl sugars. Periodate oxidation of the polysaccharide resulted in destruction of all neutral sugars and immunochemical activity against rabbit antisera. Periodate oxidation of the methyl O-methylglycosides obtained after hydrolysis of the methylated polysaccharide indicated that at least 30% of the l-fucosamine residues are substituted at C-4 in the polysaccharide. It is concluded that the polysaccharide consists of a hexosamine backbone that is substituted by d-galactosyl and kojibiosyl side-chains. The proposed terminal d-galactosyl residues apparently are sterically hindered from interacting with several d-galactose-binding proteins.     

Mucilage from a fresh-water red alga of the genus Batrachospermum

The gelatinous polysaccharides of a Batrachospermum species have been extracted from the alga. The major polysaccharide is acidic and has been separated from neutral polysaccharides by chromatography on DEAE-cellulose. The constituent sugars of the acidic polysaccharide include d- and l-galactose, d-mannose, d-xylose, l-rhamnose, d-glucuronic acid, and two O-methyl sugars, which have been characterized as 3-O-methyl-l-rhamnose (l-acofriose and 3-O-methyl-d-galactose. Partial acid hydrolysis of this polysaccharide has given a complex mixture of neutral and acidic oligosaccharides. The two preponderant acidic oligosaccharides contained galactose and glucuronic acid in 1:1 ratio, suggesting the presence of a repeating sequence of these two residues as a major structural feature of the polysaccharide.     

Structural investigations of the extracellular polysaccharides elaborated by Beijerinckia mobilis

The extracellular mucilage from Beijerinckia mobilis, a member of the Azotobacteriaceae, after removal of contaminating protein, was separated into a neutral polysaccharide (N-2, 10%); a neutral, dialysable fraction (N-1, 5%), consisting of glucose and oligosaccharides containing glucose, arabinose, and rhamnose; and an acidic polysaccharide (85%). N-2 (mol. wt, 1900) was highly branched and comprised glucopyranose, mannopyranose, and arabinofuranose residues (1:1:1). The various linkages were determined. The acid fraction was a polymer of high molecular weight composed of L-guluronic acid (65%), D-glucose (15%), and D-glycero-D-mannoheptose (20%), together with acetic and pyruvic acids. From the results of methylation, periodate oxidation, and partial hydrolysis, a branched molecule with a backbone of guluronic acid and heptose, and side chains of glucose and guluronic acid is proposed. Pyruvic acid was found to be acetal-linked to 2?5% of the heptose residues. The similarities between this polysaccharide and that from the related species Azotobacter indicum are discussed.     

Characterization of a neutral polysaccharide with antioxidant capacity from red wine

A neutral fraction (PS-SI) (0.3 g/L) with MW of 74 kDa, which contained galactose, arabinose, mannose, and glucose in the molar ratio of 1.0:0.6:0.4:0.2 was obtained by treatment of the whole polysaccharide extracted from red wine with cetrimide, followed by gel permeation chromatography. Spectroscopic and methylation analyses indicated that PS-SI is a mixture of neutral polysaccharides, consisting mainly of β (1→3)-linked galactopyranosyl residues, with side chains of galactopyranosyl residues at positions O-6. Arabinofuranosyl residues linked α (1→5), α-mannopyranosyl and glucosyl residues appear to be components of different polysaccharides. The in vitro antioxidant capacity of fractions of wine polysaccharide was studied by hydroxyl radical scavenging and ORAC assays. Fraction PS-SI presented the strongest effect on hydroxyl radicals (IC₅₀ = 0.21).     

Antioxidative activity of polysaccharide fractions isolated from Lycium barbarum Linnaeus

Antioxidant activity of polysaccharide fractions isolated from Lycium barbarum Linnaeus was evaluated. Polysaccharides were extracted with boiling water, followed by precipitating with ethanol, protein hydrolysis, dialysis, and fractionation with a DEAE–Sepharose CL-6B column. A total of 4 fractions, including 1 neutral polysaccharide (LBPN) and 3 acidic polysaccharides were obtained, and compared with crude polysaccharide (CP), crude extract of polysaccharide (CE), deproteinated polysaccharide (DP), and deproteinated and dialyzed polysaccharide (DDP) for antioxidative activity. With the exception of CE and DDP, most polysaccharides were effective in scavenging DPPH and ABTS⁺ free radicals, superoxide anion and hydroxyl radical at 1000 μg/mL.     

Structure of a pectic polysaccharide fraction from zea shoots

A pectic fraction, accounting for about 0.3% of the total cell wall polysaccharide, was derived from the hot water extract of an insoluble fraction of the buffer-homogenate of Zea shoots. The pectic polysaccharide fraction was characterized by fragmentation analysis after hydrolysis with acid and Erwinia carotovora pectate lyase. The results suggest that the fraction consists of mostly a linear homopolygalacturonan with neutral sugar components or a homogalacturonan and a rhamnogalacturonan with neutral sugar components.     

Oligosaccharides produced by partial acetolysis of xanthan gum

Partial acetolysis of the extracellular polysaccharide from Xanthomonas campestris gives the constituent monosaccharides, cellobiose, and three mannose-containing neutral oligosaccharides thought to be derived from the branch points of the polysaccharide. The structural analyses of these oligosaccharides provide further evidence for the presence of β-D-glucopyranosyl and α-D-mannopyranosyl linkages in the polymer.     

Degradation of Cell Wall Polysaccharides during Tomato Fruit Ripening

Changes in neutral sugar, uronic acid, and protein content of tomato (Lycopersicon esculentum Mill) cell walls during ripening were characterized. The only components to decline in amount were galactose, arabinose, and galacturonic acid. Isolated cell walls of ripening fruit contained a water-soluble polyuronide, possibly a product of in vivo polygalacturonase action. This polyuronide and the one obtained by incubating walls from mature green fruit with tomato polygalacturonase contained relatively much less neutral sugar than did intact cell walls. The ripening-related decline in galactose and arabinose content appeared to be separate from polyuronide solubilization. In the rin mutant, the postharvest loss of these neutral sugars occurred in the absence of polygalacturonase and polyuronide solubilization. The enzyme(s) responsible for the removal of galactose and arabinose was not identified; a tomato cell wall polysaccharide containing galactose and arabinose (6:1) was not hydrolyzed by tomato β-galactosidase.     

Study of the extracellular polysaccharides produced by a blue-green alga,Anabaena flos-aquae A-37

Summary Two types of polysaccharides were separated from the extracellular polysaccharide produced by Anabaena flos-aquae A-37 by ion exchange chromatography. The neutral polysaccharide is composed of mainly glucose with minor amounts of xylose in a molar ratio of 8:1. Glucose is believed to constitute the polysaccharide core to which xylose is attached. The acidic polysaccharide is composed of glucose and uronic acid as the major monomers with equal amounts of xylose and ribose as the minor constituents. The molar ratio of the monomers found in the acidic polymer is 6:1:1:10 as glucose: xylose: ribose: uronic acid. Chemical analyses showed that the extracellular polysaccharide consists of more neutral polymer (62%) than the acidic polymer (38%).     

Microbial degradation of gum karaya

Gum karaya (Sterculia urens gum) was degraded by a fungal isolate, a Cephalosporium sp. The patterns of carbohydrate utilization and enzyme secretion by the organism growing on the purified polysaccharide were determined, together with the ratio of neutral sugars present in the gum. Cephalosporium growth-studies indicate that the gum contains at least three different types of chains. One chain (50% of the total polysaccharide) is postulated to contain repeating units of four galacturonic acid residues containing β-D-galactose branches and having an L-rhamnose residue at the reducing end of the unit. A second chain (17% of the polysaccharide) contained 50% of galacturonic acid, 40% of rhamnose, and 10% of galactose by weight and is postulated to contain an oligorhamnan chain, containing D-galacturonic acid branch-residues, and interrupted occasionally by a D-galactose residue. D-Glucuronic acid is apparently confined to a third type of chain, comprising 33% of the polysaccharide.     

The structure and serologic distribution of an extracellular neutral polysaccharide from Pseudomonas aeruginosa immunotype 3

Previous work has described small molecular weight neutral polysaccharides from isolates of Pseudomonas aeruginosa that appear to be associated with the lipopolysaccharide (LPS) and distributed across serologic barriers defined by antibody to the O side chain. We have isolated and characterized another of these structures obtained from culture supernatants of an immunotype 3 strain of P. aeruginosa. The isolated neutral polysaccharide has a tetrasaccharide repeat unit: (formula; see text) where Rha is rhamnose. The structure was determined by 1H and 13C nuclear magnetic resonance spectroscopy including nuclear Overhauser enhancement experiments, acid hydrolysis, methylation analysis, Smith degradation, and optical rotation determinations. Polyclonal antibodies raised to intact and alkali-treated (0.1 N NaOH, 56 degrees C, 2 h) LPS from the seven Fisher immunotype strains of P. aeruginosa bound well to the neutral polysaccharide. Antibodies affinity purified from these sera using immobilized neutral polysaccharide as well as a neutral polysaccharide-specific monoclonal antibody, E87, reacted with an antigenically similar structure found among many isolates of different LPS serotypes in a colony blot and with LPS from the seven Fisher immunotypes in an immunoblot. In an immunoblot assay, the neutral polysaccharide inhibited binding of the monoclonal antibody, E87, to material present in LPS preparations from a variety of serotypes. This structure may represent another P. aeruginosa neutral polysaccharide variant found associated with the LPS.     

Structural studies on the polysaccharide of mahua (Madhuca indica) flowers

Graded hydrolysis of purified mahua polysaccharide, PS-AI, afforded four neutral and three acidic oligosaccharides, together with monosaccharides. These oligosaccharides were characterized through hydrolysis, methylation, and reduction with lithium aluminum hydride. On methylation, Smith-degraded PS-AI gave 2,3,4,6-tetra-O-methyl-d-galactose (5.5 mol), 2,3,4-tri-O-methyl-d-galactose (1 mol), 2,4,6-tri-O-methyl-d-galactose (2.2 mol), and 2,3,4-tri-O-methyl-l-arabinose (0.9 mol). Based on these results, and those obtained from methylation, periodate oxidation, and chromium trioxide oxidation studies on the polysaccharide PS-AI, a tentative structure has been assigned to the average repeating-unit in the polysaccharide.     

Structural studies on a polysaccharide obtained from the cambium layer of a bael (Aegle marmelos) tree

The purified polysaccharide isolated from the cambium layer of a young bael (Aegle marmelos) tree contains galactose, arabinose, rhamnose, xylose, and glucose in the molar ratios of 10.0:9.8:1.4:1.9:1. Methylation analysis and Smith degradation studies established the linkages of the different monosaccharide residues. The anomeric configurations of the various sugar units were determined by oxidation of the acetylated polysaccharide with chromium(VI) trioxide. The oligosaccharides isolated from the polysaccharide by graded hydrolysis were characterized. The structural significance of these results is discussed.     

Lipid-linked saccharides formed during pullulan biosynthesis in Aureobasidium pullulans

Radioactive glycolipids were extracted from cells of Aureobasidium pullulanspulsed with d-[¹⁴C]glucose. Labelled, alkali-stable lipids were resolved into one neutral and two acidic fractions. The neutral fraction was stable to mild hydrolysis with acid, whereas the acidic fractions could be hydrolysed, yielding d-glucose and a series of oligosaccharides having mobilities corresponding to those of isomaltose, panose, and isopanose. Amyloglucosidase (EC 3.2.1.3) catalysed the hydrolysis of 60% of the liberated radioactive oligosaccharides to d-glucose, indicating the presence of (1→4)-α- and (1 → 6)-α-d-glucosidic bonds. Since these lipid-linked saccharides are produced during pullulan biosynthesis in A. pullulans, it is proposed that they are intermediates in the biosynthetic pathway of that extracellular polysaccharide. A mechanism incorporating these glycolipids into a possible scheme of polysaccharide assembly is presented.     

Facile syntheses of methyl α-D-altropyranoside and its 3,4-and 4,6-O-isopropylidene derivatives

An L-arabino-D-glucurono-D-xylan isolated from the mature stalk of the reed Arundo donax contained the neutral sugars D-xylose, L-arabinose, and D-glucose in molar proportions 8.9:1:traces. 2-O-(4-O-Methyl-α-D-glucopyranosiduronic acid)-D-xylose was also present. The results of methylation analysis showing the presence of 2,3,4-tri-, 2,3-di-, 2-, and 3-O-methyl-D-xylose together with 2,3,5-tri-O-methyl-L-arabinose were determined by the gas-liquid chromatography-mass spectrometry technique and were in good agreement with those of the periodate oxidation. The D-xylan has an average degree of polymerization of about 80 and is essentially linear. The polysaccharide has structural features similar to those of polysaccharides isolated from other Gramineae.     

Characterization of a 3-linked galactan from pinus radiata callus cells

A polysaccharide was obtained in the neutral fraction of a hot water extract (100°) of cell walls, by DEAE ion exchange chromatography, from callus of Pinus radiata cells. The polysaccharide was found by sugar analysis to be composed predominantly of galactose, and methylation analysis showed it to be 3-linked. The anomeric configuration was not determined.     

Re-examination of the acid hydrolysis of 5,6-anhydro-1,2-O-isopropylidene-β-l-idofuranose

The neutral polysaccharide isolated from the fruits of Cordia dichotoma was separated into two fractions, I and II, by gel filtration using Sephadex G-100. The major fraction, II, was found to contain d-glucose and l-arabinose in the molar ratio of 21:4. The results of complete hydrolysis with acid, permethylation studies, periodate oxidation, and Smith degradation suggested it to be an arabinoglucan, and the backbone of the polysaccharide to be composed of (1→6)-linked d-gluco-pyranosyl and (1→2)-linked l-arabinofuranosyl residues. The average degree of polymerization, determined through end-group analysis, was found to be ～144.     

Structural investigation on degraded Spondias dulcis gum

Autohydrolysis of an aqueous solution of purified, exudate gum from Spondias dulcis trees yielded a degraded gum containing d-galactose, l-arabinose, and d-galacturonic acid in the mole ratios of 3:3:1. Methylation studies were conducted on the degraded gum and its carboxyl-reduced derivative. Three neutral and three acidic oligosaccharides were obtained on graded hydrolysis of the degraded gum, and these were characterized. Based on the results, a tentative structure was proposed for the repeating unit in the polysaccharide. The results of periodate oxidation supported the structure assigned. The anomeric configurations of the sugar residues were determined by studies of oxidation with chromium trioxide.     

Structures and anti-HSV-2 activities of neutral polysaccharides from an edible plant, Basella rubra L

Four neutral polysaccharides (BRN-1, BRN-2, BRN-3 and BRN-4) were isolated from the hot water extract of the aerial part of Basella rubra L. They were found to consist of a large amount of d-galactose (81.0-92.4%) and small amounts of l-arabinose (5.4-7.8%), d-glucose (2.2-11.0%) and mannose (∼2.9%). Linkage analysis revealed that all these neutral polysaccharides might be arabinogalactan type I polysaccharides in different molecular weight and chain length. Among them, only BRN-3 showed antiviral activity against herpes simplex virus type 2 (HSV-2) with 50% inhibitory concentration of 55 μg/mL without showing the cytotoxicity up to 2300 μg/mL. Furthermore, the main antiviral target of BRN-3 was shown to be the inhibition of virus adsorption to host cells. This is the first report on the neutral polysaccharide with anti-HSV-2 activity obtained from B. rubra L.