Content Of Sulfate Groups Research Articles

Effect of Ultrasonic Degradation on In Vitro Antioxidant Activity of Polysaccharides from Porphyra yezoensis (Rhodophyta)

This article aims to study the effect of ultrasonic degradation on antioxidant activity of polysaccharides from Porphyra yezoensis (Rhodophyta) (PSPY), and to look for the relationship between molecular structure of fractions (F1, F2, and F3) from ultrasonic-degraded PSPY (UDPSPY) and their activities of scavenging hydroxyl and superoxide anion radicals, chelating ability of iron ion and reducing power. Results of antioxidant assays indicated that the UDPSPY had higher antioxidant activity of scavenging superoxide anion radical and hydroxyl radical than that of the PSPY. As antioxidant activities of the fractions are concerned, this result might suggest that decreasing molecular weight and increasing sulfate group content in the molecule were vital and necessary factors for improving antioxidant activity of PSPY. Decrease of molecular weight was the dominant reason for increasing activities of scavenging non-site and site specific hydroxyl radical and reducing power of F1, F2, and F3, and increase of sulfate group content in the molecule was the dominant reason for increasing activities of scavenging superoxide anion radical and chelating ferrous ions of F1, F2, and F3. It was possible that ultrasonic treatment could be a new and effective method for enhancing PSPY's antioxidant activity.

Separation of the polysaccharides in Caulerpa racemosa and their chemical composition and antitumor activity

AbstractCaulerpa racemosa was extracted with the combined procedure of neutral protease and boiling water to yield a water‐soluble polysaccharide coded as CRP. The obtained C. racemosa polysaccharide (CRP) was fractionated with DEAE‐52 cellulose, which led to two soluble polysaccharide fractions designated as CRPF1 and CRPF2. CRP, CRPF1, and CRPF2 were chemically determined and their antitumor activity was assayed. Results showed that they were all mixtures composed of sulfated polysaccharide with 3.9–7.9% uronic acid and protein, and had similar amino acid composition, but CRP was more than CRPF1 and CRPF2 in total sugar and uronic acid content, and less in sulfate group content. Two main sugars, glucose (Glu, 56.8%) and galactose (Gal, 31.8%), of CRP were enriched to CRPF2 (Glu, 89.1%) and CRPF1 (Gal, 99.2%) respectively; Bioassay indicated that all CRP had strong antitumor activity in both in vitro and in vivo, and its inhibition rate of K562 cells in vitro at the concentration of 6.0–10.0 mg mL−1 and of H22 tumor transplanted in mice at a dose of 100 mg kg−1 day were 59.5–83.8% (48 h) and 53.9% (14 days), respectively. Moreover, at a lower dose (0.05–0.2 mg mL−1) and longer time (72 h), CRP exhibited stronger inhibition effect on K562 cells than CRPF1 and CRPF2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

CCR2 Chemokines Bind Selectively to Acetylated Heparan Sulfate Octasaccharides

Chemokines participate in well documented interactions with glycosaminoglycans (GAGs). Although many chemokine amino acid residues involved in binding have been identified, much less is known about the bound regions of GAG. Heparan sulfate (HS) is the predominant cell surface GAG, and its heterogeneous nature offers proteins a variety of structural motifs with which to interact. In the present study, we describe the interactions of three CC chemokines, MCP-1/CCL2, MCP-2/CCL8, and MCP-3/CCL7, with HS-derived oligosaccharides. To this end, we generated and characterized a complex HS octasaccharide library containing 17 different octasaccharide compositions based on acetyl and sulfate group content. Electrospray ionization mass spectrometry was used to detect chemokine-HS octasaccharide complexes in the bound state, and an affinity purification protocol was used to select and identify chemokine-binding octasaccharides from the complex mixture. The results indicate that HS octasaccharide sulfation is the foremost requirement for chemokine binding. However, within octasaccharides of constant charge density, acetylation is also observed to augment binding, suggesting that there may be as yet undiscovered specificity in the chemokine-HS interaction.

Sulfated modification of epimedium polysaccharide and effects of the modifiers on cellular infectivity of IBDV

Nine modification conditions were designed to sulfate epimedium polysaccharide (EPS) by chlorosulfonic acid–pyridine method according to orthogonal test, and nine sulfated EPS (sEPS), sEPS 1, sEPS 2, sEPS 3, sEPS 4, sEPS 5, sEPS 6, sEPS 7, sEPS 8 and sEPS 9, were obtained and their effects on IBDV infecting chick embryo fibroblast (CEF) was compared by MTT assay. The results showed that modified sEPS had significantly enhanced CEF resisting IBDV infection in comparison of non-sulfated EPS, especially, sEPS 2 and sEPS 5 presented better effects, which there were certain relationships in the degree of sulfate group (DS) and carbohydrate content. The optimum modification conditions were the reaction temperature of 80 °C, the ratio of chlorosulfonic acid to pyridine of 1:8 and the reaction time of 2 h.

カラギーナンの高吸水性樹脂としての特性評価

The absorbency values of three carrageenans (κ-carrageenan, ι-carrageenan, λ-carrageenan) in pure water and in aqueous NaCl solution were evaluated by the tea-bag method. In both pure water and aqueous NaCl solution, the order of absorbency was λ-carrageenan>ι-carrageenan>κ-carrageenan, which was in agreement with the content of sulfate groups in each carrageenan. The decrease of absorbency of carrageenans in aqueous NaCl solution was considerably lower than that of the conventional superabsorbent polymer, crosslinked sodium polyacrylate. Among them, λ-carrageenan absorbed more aqueous NaCl solution than the crosslinked sodium polyacrylate by three times or more. All carrageenans in the present study showed excellent biodegradability.

Effect of sulfate groups from sulfuric acid hydrolysis on the thermal degradation behavior of bacterial cellulose.

When used as fillers in polymer composites, the thermostability of cellulose crystals is important. Sulfate groups, introduced during hydrolysis with sulfuric acid, are suspected to diminish the thermostability. To elucidate the relationship between the hydrolysis conditions, the number of sulfate groups introduced, and the thermal degradation behavior of cellulose crystals, bacterial cellulose was hydrolyzed with sulfuric acid under different hydrolysis conditions. The number of sulfate groups in the crystals was determined by potentiometric titration. The thermal degradation behavior was investigated by thermogravimetric analysis. The sulfate group content increased with acid concentration, acid-to-cellulose ratio, and hydrolysis time. Even at low levels, the sulfate groups caused a significant decrease in degradation temperatures and an increase in char fraction confirming that the sulfate groups act as flame retardants. Profile analysis of the derivative thermogravimetric curves indicated thermal separation of the degradation reactions by the sulfate groups into low- and high-temperature processes. The Broido method was used to determine activation energies for the degradation processes. The activation energies were lower at larger amounts of sulfate groups suggesting a catalytic effect on the degradation reactions. For high thermostability in the crystals, low acid concentrations, small acid-to-cellulose ratios, and short hydrolysis times should be used.

Sulfation of silk sericin and anticoagulant activity of sulfated sericin

—Silk sericin extracted from a cocoon was sulfated by chlorosulfonic acid. Sulfation of sericin was confirmed by FT-IR and the reaction efficiency was calculated as 44.9%. 1H-NMR suggested that sulfation mainly occurred at serine residues in the sericin molecule. The sulfated sericin was separated in three fractions by gel-filtration chromatography using Sephacryl S-200. The sulfate group content and amino-acid composition of each fraction were almost identical, while the anticoagulant activity differed for each fraction of sulfated sericin. Higher anticoagulant activity was observed for the higher-molecular-mass fraction. The anticoagulant activity of sulfated sericin was estimated at 1/10 to 1/20 of heparin.

Interaction of chondroitin sulfate proteoglycans with selectins, CD44, and chemokines

Proteoglycans are ubiquitous components of cell surface membranes, basement membranes, and extracellular matrices in various tissues. They belong to a family of macromolecules that consist of core proteins to which glycosaminoglycans (GAGs), sulfated polysaccharides, are attached. Because of the high sulfate and carboxyl group content of their GAG moieties, proteoglycans have strong negative charges. This property allows them to interact with a wide range of proteins, including growth factors, enzymes, cytokines, chemokines, lipoproteins, and adhesion molecules. In this article, I will focus on the interaction of chondroitin sulfate proteoglycans with L-and P-selectin and CD 44, and chemokines, all of which have been implicated in leukocyte trafficking, and will provide evidence that a nonspecific electrostatic interaction is not the sole factor determining the interaction. I will also discuss biological implication of the interaction of chondroitin sulfate proteoglycans with L-and P-selectin and CD 44, and chemokines.

Interpolyelectrolyte reactions in solutions of functionalized dextrans with negatively charged groups along the chains

Poly(methacrylate) and functionalized dextrans (obtained by random substitution of soluble dextran with carboxylate, benzylamide, sulfate, and sulfonate groups) were labeled with fluorescent pyrenyl groups. The formation of polyelectrolyte complexes (PEC) of both labeled polyanions with poly(N-ethyl-4-vinylpyridinium) as a quencher, and the competitive reactions in solutions of the PEC were studied by means of the fluorescence quenching technique. A complete excitation of fluorescence was observed when highly sulfated or sulfonated polyanion competitors like heparin and poly(styrenesulfonate) were added to the PEC solutions. We presume that a transfer of the polycation chains from PEC to the polyanion competitors occurs. Modified dextrans are good polyanion competitors due to their content of sulfate and sulfonate groups, even in small amounts. Moreover, the affinity of carboxylate groups containing polyanion competitors to the polycation increases according to the increasing charge density of the chains. Shielding of negative charges of the polyanions by addition of low-molecular weight counterions decreases the efficiency. The data obtained show that both chemical nature of the negatively charged groups and charge density of the polyanion chains are factors that effectively control the equilibrium of competitive interpolyelectrolyte reactions.

Structural analysis of antiviral sulfated [formula omitted

The structures of two α-(1 → 3)-α- d-xylo- mannans were determined. The different antiviral activity of the xylo-mannans from Nothogenia fastigiata was explained on the basis of a flexible backbone, molecular size, content and distribution of sulfate groups and of the single stubs of β-(1 → 2)- linked d- xylose .

Antiproliferative effect and interaction of fucans with cells

Fucans were extracted from the brown seaweed Ascophyllum nodosum, degraded by acidic hydrolysis, fractionated by gel nitration and characterized by high performance steric exclusion chromatography. Different fucan fractions of average molecular weight 6000–150000 g mol −1 were thus obtained. The effects of these low molecular weight (LMW) fucans on cells were examined. The results show that these fucans can inhibit the growth of some cell lines. The Chinese hamster fibroblasts (CCL 39) are strongly inhibited, without any cytotoxicity, showing an inhibition percentage of 80% at a fucan concentration of 1000 μg ml −1, while inhibition does not exceed 50% on human colon adenocarcinoma cells (COLO 320DM) at the same fucan concentration. Other tumor cell lines examined here are not sensitive to these fucans (human mammary tumor cell line MCF7, murine leukemic cells P388 and human fibroblasts McCoy). This fucan inhibitory effect seems to be dependent on the sulfate group content. We show that no fucan molecular weight effect was observed for fractions in the range 10000–150000 g mol −1. However, the fucan fractions with a molecular weight under 10000 g mol −1 are less active. The analysis of the cells by flow cytometry shows that fucans did not induce any perturbations on the cell distribution in the various phases of the cell cycle, but they did influence the synthesis and secretion of thrombospondin. On human fibroblasts (McCoy), no antiproliferative effect was observed, but it seems that fucans led to substantial alterations of cell adhesion without any cytotoxicity. More information concerning the fucan mechanism is necessary to understand how they interact with the extracellular matrix.

Characterization of thermoplastic sulfated poly(β-hydroxyethers)/polypyrrole conducting composites

The influence of the molecular weight and the content of sulfate groups of sulfated poly(β-hydroxyethers) (S-PHE), used as dopants for polypyrrole, on the electrical and mechanical properties has been studied. It was found that the electrical conductivity of PPy/S-PHE decreased with increasing the molecular weight of S-PHE except when S-PHE with a high molar ratio of sulfation (MR) was used. The stretchability was influenced by the molecular weight as well as MR of the polyanions and exceeded 200% at a high molecular weight and a low molar ratio of sulfation. Electrochemical experiments showed a superiority of PPy/S-PHE in charge-discharge kinetics and practical charge capacity compared to polypyrrole/poly(styrenesulfonate) films.

Conductimetric titration of polyelectrolytes having sulfate and carboxyl groups

Conductimetric titration of polyelectrolyte solutions was carried out to determine the contents of sulfate and carboxyl groups. In the mixtures of poly(acrylic acid) and poly(vinyl sulfate), and of alginic acid and dextran sulfate, the contents of sulfate and carboxyl groups observed by the conductimetric titration were in agreement with those derived from the concentration of the original homopolymers. This method was applied to a viscous polysaccharide from red algae, funoran, which contains both the sulfate and carboxyl groups. These results suggested that this method is applicable to either the samples consisting of the mixture of homopolymers or those of copolymers containing both ionic species.

The sulfated polysaccharide-peptidoglycan complex potently inhibits embryonic angiogenesis and tumor growth in the presence of cortisone acetate

In combination with cortisone acetate, the sulfated polysaccharide (SP)-peptidoglycan (PG) complex produced by an Arthrobacter species was found to inhibit both embryonic angiogenesis of chick chorioallantoic membrane (CAM) and growth of solid Sarcoma 180 tumor in mice. Three fractions obtained from the SP-PG complex by gel filtration showed a great difference in the inhibitory effect on angiogenesis of the CAM, whereas in ex vivo study such a difference was reduced. Of the three fractions, SP-PG-L having the lowest molecular weight and peptidoglycan content exhibited the highest antiangiogenic and antitumor activities, even higher than those of heparin. Neither desulfation nor sulfation of the SP-PG complex greatly affected the antiangiogenic activity, and dextran sulfates and mannoglucan sulfates were lacking the activity. This suggested that glycosyl sequences of sulfated polysaccharides are more important for the activity, rather than content or intramolecular distribution of sulfate groups.

Anticoagulation activity of some sulfate‐containing polymers of the methacrylate type

AbstractA number of synthetic polymers and copolymers of the methacrylate type with a different content of sulfate, sulfamide, and carboxylic groups have been prepared. The anticoagulation activity of polymers thus obtained was compared with that of heparin. The highest anticoagulation activity was found with copolymer II containing 86 mol % of sulfate and 14 mol % of carboxylic groups. A surprisingly weak activity was observed with polymers containing sulfamide groups.

The heparitin sulfates (heparan sulfates)

Heparitin sulfate has been isolated from several sources, namely: a commercial lung polysaccharide preparation, beef lung, beef aorta, human amyloid liver, human intestine, and urine of a patient with mucopolysaccharidosis. The polysaccharides isolated were extensively purified, fractionated, and characterized. The data obtained show that heparitin sulfate is not a single compound but constitutes a family of related polymers which differ in sulfate content and in the arrangement of charged groups. These compounds are readily distinguished from most other glycosamino-glycuronans (mucopolysaccharides) by composition and optical rotation. They can be differentiated from heparin by their content of sulfate and N-acetyl groups, and D-glucuronic acid residues and by the ratio of the carbazole to orcinol uronic acid values. Due to the variations of charge distribution and molecular size, the heparitin sulfates are found to a considerable extent in admixture with other acidic polysaccharides during isolation and fractionation procedures. The particular type of heparitin sulfate obtained varies considerably with the tissue of origin. The lung-derived material was found to contain the largest range of subfractions. The heparitins isolated from aorta and amyloid liver were fairly homogenous in themselves, but differed from each other.

Basic dyeability and acid content of high‐conversion polyacrylonitrile

AbstractPrevious data have shown that the basic dyeability of acrylic polymers increases at a given specific viscosity as the peroxydisulfate‐to‐bisulfite ratio, that is, the catalyst‐toactivator (C/A) ratio, is increased. This study represents an effort to understand better the role of the initiator system on the basic dyeability, the acid group composition, and the chain composition of acrylic polymers by preparing model polymers with radioactive initiators. As the C/A ratio is increased, the molecular weight distribution broadens as measured by the M̄v/M̄n ratio, the latter obtained by osmometry. There is also a significant effect of both C/A ratio and molecular weight on the sulfate group content per molecule, but there is no effect of C/A ratio on the number of basic dye sites per molecule, the number of sulfonate groups per molecule, or the weak acid groups per molecule. These effects can be explained by invoking a chain transfer to activator reaction in addition to the usual method of chain termination by recombination. The basic dyeability is found to correlate with the number‐average molecular weight and with the number of strong acid groups plus the nonchromophoric weak acid groups.

Studies on oxidized starch sulfates for medical purposes. III. Inhibition of the proteolytic action of pepsin by sulfates of oxidized starch and its reduced products.

The inhibitory effect of polysaccharide sulfates on the proteolytic action of pepsin is due to their sulfate group and is enhanced with the increasing sulfate group content. The effect of (DP)^^- on the inhibitory activity is weaker than that of the sulfur content, but the minimum critical value is necessary for the appearance of inhibitory action. Inhibitory effect is influenced largely by (DP)^^-, especially in samples with a small sulfur content, and slightly by samples with a large sulfur content. The inhibitory activity by polysaccharide sulfates is not correlated to their anticoagulant activity.