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Developing low-temperature SO2-tolerant catalysts for the selective catalytic reduction of NOx is still a challenging task. The sulfation of active metal oxides and deposition of ammonium bisulfate deactivate catalysts, due to the difficult decomposition of the as-formed sulfate species at low temperatures ( 300°C); however, the SO2-tolerant mechanism of metal sulfate catalysts is still ambiguous. In this study, Fe2(SO4)3/TiO2 and Ce2(SO4)3/TiO2 catalysts were prepared using the corresponding metal sulfate salt as the precursor. These catalysts were tested for their low-temperature activity and SO2 tolerance activity. Compared to Ce2(SO4)3/TiO2, Fe2(SO4)3/TiO2 showed significantly better low-temperature activity and SO2 tolerance. It was demonstrated that less surface sulfate species formed on Fe2(SO4)3/TiO2 and Ce2(SO4)3/TiO2. However, the presence of NO and O2 could assist the decomposition of NH4HSO4 over Fe2(SO4)3/TiO2 at a lower temperature, endowing Fe2(SO4)3/TiO2 with better low-temperature SO2 tolerance than Ce2(SO4)3/TiO2. This study unraveled the SO2-tolerant mechanism of Fe2(SO4)3/TiO2 at lower temperatures (

Sulfation is an essential modification on biomolecules in living cells, and 3'-Phosphoadenosine-5'-phosphosulfate (PAPS) is its unique and universal sulfate donor. Human PAPS synthases (PAPSS1 and 2) are the only enzymes that catalyze PAPS production from inorganic sulfate. Unexpectedly, PAPSS1 and PAPSS2 do not functional complement with each other, and abnormal function of PAPSS2 but not PAPSS1 leads to numerous human diseases including bone development diseases, hormone disorder and cancers. Here, we reported the crystal structures of ATP-sulfurylase domain of human PAPSS2 (ATPS2) and ATPS2 in complex with is product 5'-phosphosulfate (APS). We demonstrated that ATPS2 recognizes the substrates by using family conserved residues located on the HXXH and PP motifs, and achieves substrate binding and releasing by employing a non-conserved phenylalanine (Phe550) through a never observed flipping mechanism. Our discovery provides additional information to better understand the biological function of PAPSS2 especially in tumorigenesis, and may facilitate the drug discovery against this enzyme.

Marine ecosystem associated organisms are an affluent source of bioactive compounds. Polysaccharides with unique structural and practical entities have gained special studies interest inside the current biomedical zone. Polysaccharides are the main components of marine algae, plants, animals, insects, and microorganisms. In recent times research on seaweed is more persistent for extraction of natural bioactive “Sulfated polysaccharides” (SP). The considerable amount of SP exists in the algae in the form of fucans, fucoidans, carrageenans, ulvan, etc. Major function of SP is to act as a defensive lattice towards the infective organism. All SP possess the high potential and possess a broad range of therapeutic applications as antitumor, immunomodulatory, vaccine adjuvant, anti-inflammatory, anticoagulant, antiviral, antiprotozoal, antimicrobial, antilipemic, therapy of regenerative medicine, also in drug delivery and tissue engineering application. This review aims to discuss the biomedicine applications of sulfated polysaccharides from marine seaweeds.

Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.

Cardamine hupingshanensis polysaccharide (CHP) was modified by the sulfur trioxide–pyridine method to obtain the sulfated C. hupingshanensis polysaccharide (SCHP) with a substitution degree of 0.72. The spectral results revealed that the sulfate group was successfully introduced to CHP. In the in vitro antioxidant assay, SCHP showed the highest scavenging rate of hydroxyl radicals, ABTS, and DPPH. Different concentrations of SCHP were chosen to form a compound with Zein to prepare novel bioactive films successfully. The functional and characterization studies of the films were also conducted. The scavenging ability of the films for hydroxyl radicals, ABTS, and DPPH was improved by adding different concentrations of SCHP. Although the films showed a decrease in transparency with the addition of 4 mg/ml SCHP, there was an improvement in tensile strength compared to films without the addition of SCHP. These findings indicate that Zein‐SCHP films can be used as a functional food packaging material with antioxidant properties., Edible composite films were produced using sulfated Cardamine hupingshanensis polysaccharides. The composite film has good antioxidant function.

Furin is one of the nine-member proprotein convertase family. Furin cleaves proteins with polybasic residues, which includes many viral glycoproteins such as SARS-Cov-2 spike protein. The cleavage is required for the activation of the proteins. Currently, the mechanisms that regulate Furin activity remain largely unknown. Here we demonstrated that Furin is a novel heparin/heparan sulfate binding protein by the use of biochemical and genetic assays. The KD is 9.78 nM based on the biolayer interferometry assay. Moreover, we found that sulfation degree, site-specific sulfation (N-sulfation and 3-O-sulfation), and iduronic acid are the major structural determinants for the binding. Furthermore, we found that heparin inhibits the enzymatic activity of Furin when pre-mixes heparin with either Furin or Furin substrate. We also found that the Furin binds with cells of different origin and the binding with the cells of lung origin is the strongest one. These data could advance our understanding of the working mechanism of Furin and will benefit the Furin based drug discovery such as inhibitors targeting the interaction between heparan sulfate and Furin for inhibition of viral infection. Supplementary information The online version contains supplementary material available at 10.1007/s10719-021-10018-8.

Macroalgae (seaweeds) are abundant in functional polysaccharides known for their unique biochemical activities. In this study, the antioxidant, anti-lipogenic, and anti-inflammatory activities of the fucoidan extracted from brown seaweed Sargassum siliquosum were investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging ability, lipid synthesis inhibition, and suppression of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) production, respectively. To examine the effect of molecular mass on fucoidan's bioactivities above, the extracted fucoidan was subject to hydrogen peroxide-mediated partial hydrolysis to obtain lower molecular mass compounds within the range of 107.3–3.2 kDa. Results indicated that fucoidan's antioxidant activity increased with a corresponding decrease in molecular mass; the dosage for the half-maximal response (EC50) dropped from 2.58 to 1.82 mg/mL when the molecular mass decreased from 107.3 to 3.2 kDa. In addition, both the anti-lipogenesis and anti-inflammatory activities of fucoidan were significantly enhanced by 71.1% and 36.7%, respectively, when the molecular mass decreased to about 3 kDa. To further test the effect of sulfation on fucoidan's bioactivities, low molecular mass fucoidan was treated with SO3-DMF to increase the sulfate content. The results indicated that when sulfate content increased from 18.7% to 32.1%, EC50 of DPPH decreased from 1.82 mg/mL to 0.86 mg/mL and the anti-inflammatory activity also increased by 35.2%; however, the anti-lipogenesis activity decreased.

In the present study, Sulfated polysaccharides were extracted from macroalga Sargassum whitey collected from the Gulf of Mannar, Tamil Nadu, India. The maximum yield of 1.95g sulfated polysaccharide was extracted from Sargassum whitey and 0.81mg/ml of purified sulfated polysaccharide was obtained through DEAE anion exchange chromatography. The purified form was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray spectroscopy (EDX), and Field Emission Scanning Electron Microscopy (FESEM) analyses. The in vitro biological properties such as antibacterial, antioxidants activity (DPPH, Hydroxyl & Superoxide anion) of sulfated polysaccharides were evaluated and the results showed that 45μg mL-1 concentration of sulfated polysaccharide exhibited good antibacterial inhibitory activity against all the tested pathogenic bacteria strains, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. The in vitro antioxidant activity also found to be significant, where the exhibited IC50 concentrations by the purified sulfated polysaccharide was 183.2µg/mL for DPPH, 204.2µg/mL for superoxide anion, and 163.8µg/mL for Hydroxyl scavenge free radicals activities.

Wound healing remains as a dynamic process and the type of dressing material significantly affects the efficacy of healing. The identification of ideal dressings to use for a particular wound type is an important requisite facilitating the entire process of healing. Chronic, high exudate wounds are dynamic in presentation and remain as a major health care burden. Researchers have sort to design and optimize biodegradable wound dressings that focuses to optimize moisture retentiveness, as superior character in the healing process. In addition, dressings have been designed to visualize the wound bed by improving the optical property, target and kill infection-causing bacteria, with the incorporation of antimicrobial agents, nanomaterials and numerous other measures. For the practitioners, choosing the optimal dressing decreases time to healing, provides cost-effective care and improves patient quality of life. The current mini review highlights the ideal characters of wound dressing materials and presents insights on the superior characters of carrageenan bio composites for prospective advancements in research in the area of wound care and management.

Background: Sargassum polycystum C. Agardh has potent antioxidant and antiinflammatory properties. However, its anti-allergic effect has not yet been reported. In this study, we investigated the anti-allergic effects of sulfated polysaccharide of S. polycystum (SPSP) in Dinitrofluorobenzene (DNFB)- induced allergic contact dermatitis animal model. Methods: SPSP was extracted through the hot water extraction method and was subjected to compositional analyses. For the Allergic Contact Dermatitis (ACD) model, symptoms were induced by the topical application of 0.5% DNFB on the shaved ventral skin of mice. SPSP (500, 1000, and 2000 mg/kg) and Prednisolone were orally administered for seven days after sensitization. Elicitation was performed seven days later with 0.2% DNFB. After this, ear thickness was measured at baseline and 24 hours post elicitation using a dial thickness gauge. Serum of mice was obtained 24 hours post elicitation, and the level of IFNγ and TNFα was quantified by enzyme-linked immunosorbent assays (ELISA). Results: SPSP afforded 33.6% carbohydrates, 23.7% sulfate, 7.5% protein, and 1.5% uronic acid contents. SPSP inhibited the ear swelling and cytokines (IFNγ and TNFα) production in DNFBinduced mice in a dose-dependent manner. In comparison with Prednisolone (p>0.05), the highest concentration (2000 mg/kg) of SPSP showed a comparable anti-allergic effect. Conclusion: These findings showed that the sulfated polysaccharide from S. polycystum is a potential natural source to treat allergic contact dermatitis. The effect is attributed to the polysaccharideprotein complex present in the extract, but further studies are needed to establish the exact mechanism of action of SPSP in the treatment of the disease.

Objective: Malignant melanoma is a highly metastatic cutaneous cancer. Deregulated apoptosis has been identified as a major cause of cancer drug resistance. The objective of the study is to evaluate antiproliferative activity of Hypnea Valentiae extract in human skin malignant melanoma (SK-MEL) cells. Methods: In this study, sulfated polysaccharide fraction was precipitated from aqueous extract obtained from H. valentiae. MTT assay was used to determine the cell viability of the crude sulfated polysaccharide against SK-MEL cells and normal L6 cell line (Rat skeletal muscle). Acridine orange (AO) and Ethidium bromide (EB) staining method was applied to study induction of apoptosis in SK-MEL cells. Results: Dose-dependent reduction in cell viability was observed with an IC50 of 30 μg/ml in SK-MEL cancer cells. The sulfated polysaccharide treated SK-MEL cells followed by AO, EB staining, showed typical early apoptotic, and late apoptotic morphological changes. Conclusion: The isolated crude sulfated polysaccharide from H. valentiae produced potent growth inhibition and induction of apoptosis in SK-MEL cells but caused no cytotoxicity in normal L6 skeletal muscle cells.

Heparan sulfate (HS) 3-O-sulfotransferase isoform 4 (3-OST-4) is a specialized carbohydrate sulfotransferase participating in the biosynthesis of heparan sulfate. Here, we report the expression and purification of the recombinant 3-OST-4 enzyme and use it for the synthesis of a library of 3-O-sulfated hexasaccharides and 3-O-sulfated octasaccharides. The unique structural feature of the library is that each oligosaccharide contains a disaccharide domain with a 2-O-sulfated glucuronic acid (GlcA2S) and 3-O-sulfated glucosamine (GlcNS3S). By rearranging the order of the enzymatic modification steps, we demonstrate the synthesis of oligosaccharides with different saccharide sequences. The structural characterization was completed by electrospray ionization mass spectrometry and NMR. These 3-O-sulfated oligosaccharides show weak to very weak anti-Factor Xa activity, a measurement of anticoagulant activity. We discovered that HSoligo 7 (HS oligosaccharide 7), a 3-O-sulfated octasaccharide, binds to high mobility group box 1 protein (HMGB1) and tau protein, both believed to be involved in the process of inflammation. Access to the recombinant 3-OST-4 expands the capability of the chemoenzymatic method to synthesize novel 3-O-sulfated oligosaccharides. The oligosaccharides will become valuable reagents to probe the biological functions of 3-O-sulfated HS and to develop HS-based therapeutic agents.

Osteoporosis, one of the most serious public health concerns caused by an imbalance between bone resorption and bone formation, has a major impact on the population. Therefore, finding the effective osteogenic compounds for the treatment of osteoporosis is a promising research approach. In our study, tamarind (Tamarindus indica L.) seed polysaccharide (TSP) extracted from tamarind seed was subjected to synthesize its sulfate derivatives. The 1H NMR, FT-IR, SEM, monosaccharide compositions and elemental analysis data revealed that tamarind seed polysaccharide sulfate (TSPS) was successfully prepared. As the result, TSPS showed potent effects on inducing osteoblast differentiation via increasing alkaline phosphatase (ALP) activity up to 20% after 10 days and bone mineralization approximately 58% after four weeks at concentration of 20 μg/mL, whereas no statistically increase for both ALP activity and bone mineralization was observed in TSP treatment. Furthermore, TSPS enhanced expression of several marker genes in bone formation. Overall, the obtained data provided novelty on osteogenic compounds originated from TSP of T. indica, as well as scientific fundamentals on drug development and bone tissue engineering for the treatment of osteoporosis and other bone-related diseases.

Chitosan/fucoidan nanoparticles were created using two fucoidans from the Fucus evanescens algae. One of them was a regular fucoidan obtained for the first time from the alga harvested at the reproductive growth stage, using only standard extraction methods, without additional modifications. Its structure was established via NMR spectroscopy to consist of the repeating →3)-α-L-Fucp-(2,4SO3−)-(1 → 4)-α-L-Fucp-(2SO3−)-(1→ fragment. Such fragment also coustituted 55% of the other fucoidan's structure, however it also included long sequences of α-L-fucopyranose residues sulfated only at C2. The nanoparticles were re-dispersed in water and the influence of fucoidan/chitosan mass ratio on the nanoparticles' size and zeta potential was investigated. 3D models of the regular fucoidan and chitosan's sections were created and their molecular docking was performed, showing that either polymer could occupy the exterior of the complex, depending on their ratio. Thermodynamic parameters of fucoidan-chitosan binding process were accessed, with the results indicating that significant conformational changes of fucoidan and chitosan molecules take place during the interaction, presumably to allow for more effective binding.

BackgroundSulfate modification ofN-glycans is important for several biological functions such as clearance of pituitary hormones or immunoregulation. Yet, the prevalence of thisN-glycan modification and its functions remain largely unexplored. Characterization ofN-glycans bearing sulfate modifications is hampered in part by a lack of enzymes that enable site-specific detection ofN-glycan sulfation. In this study, we used functional metagenomic screening to identify enzymes that act upon sulfated N-acetylglucosamine (GlcNAc). Using multiplexed capillary gel electrophoresis with laser-induced fluorescence detection (xCGE-LIF) -based glycoanalysis we proved their ability to act upon GlcNAc-6-SO4onN-glycans.ResultsOur screen identified a sugar-specific sulfatase that specifically removes sulfate from GlcNAc-6-SO4when it is in a terminal position on anN-glycan. Additionally, in the absence of calcium, this sulfatase binds to the sulfated glycan but does not remove the sulfate group, suggesting it could be used for selective isolation of sulfatedN-glycans. Further, we describe isolation of a sulfate-dependent hexosaminidase that removes intact GlcNAc-6-SO4(but not asulfated GlcNAc) from a terminal position onN-glycans. Finally, the use of these enzymes to detect the presence of sulfatedN-glycans by xCGE-LIF is demonstrated.ConclusionThe present study demonstrates the feasibility of using functional metagenomic screening combined with glycoanalytics to discover enzymes that act upon chemical modifications of glycans. The discovered enzymes represent new specificities that can help resolve the presence of GlcNAc-6-SO4inN-glycan structural analyses.

A diversity-oriented chemoenzymatic approach for the collective preparation of sulfated core 2 O-GalNAc glycans and their nonsulfated counterparts was described. A sulfated trisaccharide and a nonsulfated trisaccharide were chemically synthesized by combining flexible protected group manipulations and sequential one-pot glycosylations. The divergent enzymatic extension of these two trisaccharides, using a panel of robust glycosyltransferases that can recognize sulfated substrates and differentiating the branches with specifically designed glycosylation sequences to achieve regioselective sialylation, provided 36 structurally well-defined O-GalNAc glycans.

We previously obtained and characterized a novel sulfated derivative of the exopolysaccharides from Enterobacter cloacae Z0206 (SEPS). This study aimed at investigating the effects and mechanism of SEPS against dextran sulfate sodium (DSS) induced intestinal injury. The results showed that SEPS increased the proliferation and survival of intestinal epithelial cells during DSS stimulation. Furthermore, SEPS maintained the barrier function and inflammatory response via JAK2 and MAPK signaling to protect against DSS-induced intestinal injury. Mechanistically, SEPS elevated the DNA methylation in the promoter region to negatively regulate the JAK2 and MAPKs expression. Thus, the current study shows the potential effects and mechanism of SEPS on DSS-induced intestinal epithelial cell injury.

Glial-cell-line-derived neurotrophic factor (GDNF) is a protein that has therapeutic potential in the treatment of Parkinson's disease and other neurodegenerative diseases. The activity of GDNF is highly dependent on the interaction with sulfated glycans which bind at the N-terminus consisting of 19 residues. Herein, we studied the influence of different glycosaminoglycan (i.e., glycan; GAG) molecules on the conformation of a GDNF-derived peptide (GAG binding motif, sixteen amino acid residues at the N-terminus) using both experimental and theoretical studies. The GAG molecules employed in this study are heparin, heparan sulfate, hyaluronic acid, and sulfated hyaluronic acid. Circular dichroism spectroscopy was employed to detect conformational changes induced by the GAG molecules; molecular dynamics simulation studies were performed to support the experimental results. Our results revealed that the sulfated GAG molecules bind strongly with GDNF peptide and induce alpha-helical structure in the peptide to some extent.

Bile acids play essential roles in facilitating the intestinal absorption of lipophilic nutrients as well as regulation of glucose, lipid, and energy homeostasis via activation of some receptors. Bile acids are cytotoxic, and consequently their concentrations are tightly controlled. A critical pathway for bile acid elimination and detoxification is sulfation. The pattern of bile acid sulfation differs by species. Sulfation preferentially occurs at the 3α-OH of bile acids in humans, but at the 7α-OH in mice. A recent study identified mouse cytosolic sulfotransferase 2A8 (mSULT2A8) as the major hepatic 7α-hydroxyl bile acid-sulfating enzyme. To elucidate the 7α-OH specific sulfation mechanism of mSULT2A8, instead of 3α-OH specific sulfation in humans, we determined a crystal structure of mSULT2A8 in complex with cholic acid, a major bile acid, and 3'-phosphoadenosine-5'-phosphate, the sulfate donor product. Our study shows that bile acid-binding mode of mSULT2A8 and how the enzyme holds the 7α-OH group of bile acids at the catalytic center, revealing that the mechanism underlying 7α-OH specific sulfation. The structure shows the substrate binds to mSULT2A8 in an orientation perpendicular to that of human 3α-hydroxyl bile acid-sulfotransferase (hSULT2A1). The structure of the complex provides new insight into species different bile acid metabolism.

The aim of this study was to establish the fine structure of fucoidan from Sargassum oligocystum and to study the radiosensitizing effect of fucoidans from three algae of genus Sargassum (S. oligocystum, S. duplicatum, and S. feldmannii) with different structures. The fucoidan SoF2 from S. oligocystum was sulfated (32%) galactofucan (Fuc:Gal = 2:1), with a Mw of 183 kDa (Mw/Mn = 2.0). Its supposed structure was found to be predominantly 1,3-linked fucose as the main chain, with branching points at C2 and C4. The branches could be single galactose and/or fucose short chains with terminal galactose residues. Sulfate groups were found at positions C3, C2, and/or C4 of fucose residues and at C2 and/or C4 of galactose residues. The radiosensitizing effect of galactofucans from S. oligocystum, S. duplicatum, and S. feldmannii against human melanoma SK-MEL-28, colon HT-29, and breast MDA-MB-231 cancer cells was investigated. The influence of all investigated polysaccharides treatments with/without X-ray radiation on colony formation of human melanoma cells SK-MEL-28 was weak. Fucoidan from S. feldmannii has been shown to be the most promising radiosensitizing compound against human colon HT-29 and breast MDA-MB-231 cancer cells.

Heparosan is used as the starting polysaccharide sulfated using sulfotransferase to generate fully elaborate heparin, a widely used clinical drug. However, the preparation of heparosan and enzymes was considered tedious since such material must be prepared in separate fermentation batches. In this study, a commonly admitted probiotic, Escherichia coli strain Nissle 1917 (EcN), was engineered to intracellularly express sulfotransferases and, simultaneously, secreting heparosan into the culture medium. The engineered strain EcN::T7M, carrying the λDE3 region of BL21(DE3) encoding T7 RNA polymerase, expressed the sulfotransferase domain (NST) of human N-deacetylase/N-sulfotransferase-1 (NDST-1) and the catalytic domain of mouse 3-O-sulfotransferase-1 (3-OST-1) in a flask. The fed-batch fermentation of EcN::T7M carrying the plasmid expressing NST was carried out, which brought the yield of NST to 0.21 g/L and the yield of heparosan to 0.85 g/L, respectively. Furthermore, the heparosan was purified, characterized by 1H nuclear magnetic resonance (NMR), and sulfated by NST using 3′-phosphoadenosine-5′-phosphosulfate (PAPS) as the sulfo donor. The analysis of element composition showed that over 80% of disaccharide repeats of heparosan were N-sulfated. These results indicate that EcN::T7M is capable of preparing sulfotransferase and heparosan at the same time. The EcN::T7M strain is also a suitable host for expressing exogenous proteins driven by tac promoter and T7 promoter.

Synthesis, structural features, and paramagnetic properties of manganese-containing nanocomposites based on polysaccharides arabinogalactan, sulfated arabinogalactan, and κ-carrageenan have been st...

BACKGROUND The separation and purification of Porphyra haitanensis polysaccharide (PHP), and the determination of changes in molecular weight (Mw) and antioxidant capacity after in vitro digestion, were undertaken. RESULTS Analysis of two polysaccharide fractions (PHP0.5-1-UF and PHP1.0-1-UF) by various techniques showed that they were very pure sulfated polysaccharides without pigment or protein. PHP0.5-1-UF was filamentous or 'tape-like' sheets, whereas PHP1.0-1-UF had some filaments and large numbers of rounded aggregates. The Mw of PHP, PHP0.5-1-UF and PHP1.0-1-UF was 2.06 x 10(6) (+/- 2.02%), 6.68 x 10(6) (+/- 3.17%), and 1.14 x 10(6) (+/- 3.44%) (g mol(-1)), respectively. After in vitro digestion, the Mw of PHP, PHP0.5-1-UF, and PHP1.0-1-UF decreased. Their antioxidant capacities were markedly higher than before digestion, especially PHP0.5-1-UF and its digestion products, which might be related to the reductions in Mw. CONCLUSION These findings provide a greater understanding of the separation and purification of sulfated polysaccharides and the influence of digestion on biological activity. They also contribute to the practical application of sulfated polysaccharides in functional foods. (c) 2021 Society of Chemical Industry.

In this study, an enzyme-assisted extraction method was used to extract Orchis chusua D. Don (Salep) polysaccharide (SP), which was then modified by sulfation, acetylation, phosphorylation, and carboxymethylation to obtain modified polysaccharides. Furthermore, their degree of substitution, chemical composition, and molecular weight were evaluated. The primary structural features were characterized by UV spectra, FT-IR spectra, Congo-red test, and scanning electron microscope. The phosphorylated polysaccharide (SP-P) was demonstrated the highest scavenging ability on hydroxyl radical and growth-promoting activity on Lactobacillus Bulgaricus. The carboxymethylated polysaccharide (SP-C) was exhibited the strongest DPPH and ABTS radical scavenging effects. The acetylated polysaccharide (SP-A) displayed the best proliferation effects on Bifidobacterium adolescentis, whereas the sulfated polysaccharide (SP-S) maintained moderately stable antioxidant and probiotic ability. These findings indicate that the modified polysaccharides had their potential significance as new antioxidants and probiotics for the food industry. PRACTICAL APPLICATION: This article provides a new source for the development of polysaccharide derivatives as new antioxidants and probiotics for the food industry.

Fucoidan from brown seaweed has been proposed as a potential therapeutic due to its properties. Fucoidan is a sulfated polysaccharide and has been shown to have several biological activities, including antibacterial, antiviral, and anticoagulant. In this study, fucoidan was extracted from Sargassum plagiophyllum, Sargassum aquifolium, and Sargassum polycystum collected from southern Thailand. Fucoidan from S. plagiophyllum and S. polycystum was obtained in significantly higher yields (3.6-fold) than that obtained from S. aquifolium. Fucoidan from the former two seaweed species with higher fucoidan contents was evaluated for its potential benefits. The fucoidan extracted from S. plagiophyllum and S. polycystum contained both sulfate and glucuronic acid conjugates at approximately 28.0% and 7.7% of the fucoidan content and 33.5% and 12.8% of the fucoidan content, respectively. In addition, fucoidan extracted from both S. plagiophyllum and S. polycystum had antioxidant activity and suppressed tumor necrosis factor alpha (TNF-α) production from lipopolysaccharide (LPS) activated macrophages. Interestingly, the half-maximal inhibitory concentrations (IC50 values) of fucoidan in the breast cancer cell line MCF-7 were 250 μg mL−1 from S. plagiophyllum and 190 μg mL−1 from S. polycystum. Additionally, 200 μg mL−1 fucoidan from both species had inhibitory properties similar to those of the anti-cholesterol drug simvastatin in Randox reaction cholesterol assays. Overall, the results of this study imply that fucoidan from S. plagiophyllum and S. polycystum has potential health benefits. This study confirms the beneficial properties of fucoidan from its habitat in southern Thailand. Herein is the first report of the bioactivities of fucoidan from S. plagiophyllum, while the bioactivities of fucoidan from S. polycystum were used for comparative study. However, both fucoidans require further research.

The effects of sulfation and calcium cations (Ca2+) on the atomic-resolution conformational properties of chondroitin carbohydrate polymers in aqueous solutions are not well studied owing to experimental challenges. Here, we compare all-atom explicit-solvent molecular dynamics simulations results for pairs of O-type (nonsulfated) and A-type (GlcNAc 4-O-sulfated) chondroitin 20-mers in 140 mM NaCl with and without Ca2+ and find that both sulfation and Ca2+ favor more compact polymer conformations. We also show that subtle differences in force-field parametrization can have dramatic effects on Ca2+ binding to chondroitin carboxylate and sulfate functional groups and thereby determine Ca2+-mediated intra- and interstrand association. In addition to providing an atomic-resolution picture of the interaction of Ca2+ with sulfated and nonsulfated chondroitin polymers, the molecular dynamics data emphasize the importance of careful force-field parametrization to balance ion-water and ion-chondroitin interactions and suggest additional parametrization efforts to tune interactions involving sulfate.

Background Diabetes mellitus is an endocrine and metabolic system disease characterized by hyperglycaemia and insulin resistance, and has become a prevalent disease around the world. Fucoidan has a good hypoglycaemic effect and ideal development potential in the treatment of diabetes based on their specific chemical structures, such as monosaccharide compositions and glycosidic linkages. Scope and approach However, the relationship between structure-function and activity has not yet been clarified. This article discusses the structural characteristics of fucoidan, including its backbone structure, glycosidic bond positions, monosaccharide types, sulphate content, and molecular weight. The potential therapeutic effect of fucoidan on hyperglycaemia and diabetic complications caused by diabetes is also reviewed. Key findings and conclusions Fucoidan reduces blood sugar levels through α-amylase and α- d -glucosidase inhibition, a Sirt-1-dependent manner, and the cAMP, PI3K/AKT, and JNK/AKT signalling pathways. The outstanding biological function of fucoidan is due its unique chemical structure. Among them, fucoidan of low molecular weight and high degree of sulfation displays greater anti-diabetic activity, and persulphated fucoidan derivatives showed significantly enhanced hypoglycaemic activities. Moreover, only (1,3) and (1,4) alternatively linked fucoidan showed a stronger inhibitory effect on α- d -glucosidase.

Background:: Vitexin is a natural flavonoid compound with multiple pharmacological activities and is extracted from the leaves and seeds of Vitex negundo L. var. cannabifolia (Sieb. et Zucc.) Hand.-Mazz. However, the metabolite characterization of this component remains insufficient. Objective:: To establish a rapid profiling and identification method for vitexin metabolites in rat urine, plasma and faeces after oral administration using a UHPLC-Q-Exactive orbitrap mass spectrometer were coupled with multiple data-mining methods. Methods:: In this study a simple and rapid systematic strategy for the detection and identification of constituents was proposed based on UHPLC-Q-Exactive Orbitrap mass spectrometry in parallel reaction monitoring mode combining diagnostic fragment ion filtering techniques. Results:: A total of 49 metabolites were fully or partially characterized based on their accurate mass, characteristic fragment ions, retention times, corresponding ClogP values, and so on. It is obvious that C-glycosyl flavonoids often display an [M+H-120]+ ion that represents the loss of C4H8O4. As a result, these metabolites were presumed to be generated through glucuronidation, sulfation, deglucosylation, dehydrogenation, methylation, hydrogenation, hydroxylation, ring cleavage and their composite reactions. Moreover, the characteristic fragmentation pathways of flavonoids, chalcones and dihydrochalcones were summarized for the subsequent metabolite identification. Conclusion:: The current study provided an overall metabolic profile of vitexin which will be of great help in predicting the in vivo pharmacokinetic profiles and understanding the action mechanism of this active ingredient.

Heparan sulfate (HS) is a linear and complex polysaccharide that modulates the biological activities through protein recognition and interaction. Evidence indicates that protein-binding properties of HS are largely dependent on distinctive sulfation and epimerization patterns that are modified by a series of Golgi-localized enzymes. In particular, the glucuronyl C5-epimerase (Hsepi) converts D-glucuronic acid (GlcA) residues to L-iduronic acid (IdoA) and 2-O-sulfotransferase (2OST) catalyzes sulfation at C2 position of IdoA and rarely GlcA residues. Mice lacking both Hsepi and 2OST display multiple development defects, indicating the importance of IdoA in HS. Here, to gain greater insights of HS structure–function relationships, as well as a better understanding of the regulatory mechanisms of Hsepi and 2OST, the fine structure and cellular signaling functions of HS were investigated after restoration of Hsepi in the mutant mouse embryonic fibroblast (MEF) cells. Introduction of Hsepi into the Hsepi mutant MEF cells led to robustly increased proportion of IdoA residues, which rescued the cell signaling in response to fibroblast growth factor 2. However, we found that Hsepi knockout had no influence on either cellular transport or enzymatic activity of 2OST in the MEF cells, which is not in accord with the findings suggesting that the enzymatic activity and cellular transport of 2OST and Hsepi might be differently regulated.

Pleiotrophin (PTN) is a potent mitogenic cytokine whose activities are controlled by its interactions with glycosaminoglycan (GAG). We examined the specificity of PTN for several types of GAG oligosaccharides. Our data indicate that the interaction of PTN with GAGs is dependent on the sulfation density of GAGs. Surprisingly, an acidic peptide also had similar interactions with PTN as GAGs. This shows that the interaction of PTN with anionic polymers is flexible and adaptable and that the charge density is the main determinant of the interaction. In addition, we show that PTN can compensate for the loss of its termini in interactions with heparin oligosaccharides, allowing it to maintain its affinity for GAGs in the absence of the termini. Taken together, these data provide valuable insight into the interactions of PTN with its proteoglycan receptors.

Sulfated carbohydrate metabolism is a fundamental process, which occurs in all domains of life. Carbohydrate sulfatases are enzymes that remove sulfate groups from carbohydrates and are essential to the depolymerisation of complex polysaccharides. Despite their biological importance, carbohydrate sulfatases are poorly studied and challenges remain in accurately assessing the activity, specificity and kinetic parameters. Most notably, separation of desulfated products from sulfated substrates is currently a time-consuming process. In this paper, we describe the development of rapid capillary electrophoresis coupled to substrate fluorescence detection as a high-throughput and facile means of analysing carbohydrate sulfatase activity. The approach has utility for the determination of both kinetic and inhibition parameters and is based on existing microfluidic technology coupled to a new synthetic fluorescent 6S-GlcNAc carbohydrate substrate. Furthermore, we compare this technique in terms of both time and resources, to high performance anion exchange chromatography and NMR-based methods, which are the two current ‘gold standards’ for enzymatic carbohydrate sulfation analysis. Our study clearly demonstrates the advantages of mobility shift assays for the quantification of near real-time carbohydrate desulfation by purified sulfatases, and could support the search for small molecule inhibitors of these disease-associated enzymes.One sentence summarySulfatases remove sulfate groups from biomolecules; in this study we report a rapid and robust capillary electrophoresis assay for the quantification of carbohydrate desulfation.

A fucoidan, sulfated polysaccharide, was extracted from the brown seaweed Cystoseira schiffneri during 4 harvest periods (December, April, July, and September) and studied for its structural and chemical properties. The Cystoseira schiffneri fucoidan (CSF) showed important variation in sulfate content ranging from 7.8% in December to 34.8% in July. This was confirmed by Fourier transform infrared and nuclear magnetic resonance spectroscopies showing characteristic signals of sulfated polysaccharides. Molecular mass of the CSF varied as a function of season from 3,745 in December to 26,390 Da in July. Gas chromatography–mass spectroscopy showed that CSF fractions were “mannogalactofucans” composed mainly of mannose, fucose, and galactose with low levels of other monosaccharides. Moreover, interesting in vitro antioxidant activities that depend on the harvest season were noted for CSF. Thus, the present work might contribute to establish criteria for extracting bioactive fucoidans from an endemic Tunisian seaweed C. schiffneri., A novel fucoidan, mannogalactofucan, was extracted from the brown seaweed Cystoseira schiffneri. Mw of extracted fucoidans increased from 3,745 at December to 26,390 Da at July. The fucoidans showed interesting in vitro antioxidant activities that depend on the harvest season.

Chondroitin sulfate (CS) is widely applied in the medical, clinical, and nutraceutical fields. However, all commercialized CS is extracted from animal tissues, which is associated with many problems, such as heavy reliance on antibiotics, animal excrement waste and long breeding time. Here, we developed a promising new green route for the de novo biosynthesis of non-animal CS from methanol, a one-carbon compound, using the engineered Pichia pastoris cell factory. Firstly, three exogenous genes, namely kfoC and kfoA from Escherichia coli K4 and tuaD from Bacillus subtilis, were introduced into P. pastoris to construct the chondroitin synthesis pathway, which yielded 5.5 mg L−1 chondroitin. After optimizing the expression of committed enzymes by codon optimization, the production of chondroitin improved by approximately 35-fold to 189.8 mg L−1. Thereafter, 6 kinds of Kozak sequences and 10 different endogenous promoters were compared and applied to achieve the expression of active chondroitin-4-O-sulfotransferase (41.3 U L−1). After integrating the chondroitin biosynthesis and sulfonation modules, the engineered strain, Pp006, successfully produced 182.0 mg L−1 CSA [GlcA-GalNAc (4S)] with a sulfation degree of 1.1%. We further improved the sulfation degree to 2.8% by strengthening the 3′-phosphoadenosine-5′-phosphosulfate (PAPS) supply with the overexpression of adenosine-5′-triphosphate sulfurylase and adenosine 5′-phosphosulfate kinase. In the fed-batch cultivation, the final titer of CSA reached 2.1 g L−1 and the sulfation degree increased to 4.0%. Moreover, the results suggest that the P. pastoris cell factory could be used as a green route to produce other sulfated glycosaminoglycans.

Currently, refined edible oils are used to produce biodiesel with the help of a base catalyst. The most important problem with the base-catalyzed esterification process is that they produce soap when they have higher free fatty acids (FFA). The present study indicates that montmorillonite (k10) can be a significant catalyst prepared by the impregnation method using H2SO4 in the ratio of 1:5. The prepared novel catalyst was characterized using XRD, FTIR and SEM-EDS techniques. The optimum conditions for esterification have been determined by applying RSM with CCD methodology for each significant variable like oil-methanol molar ratio, catalyst amount, reaction time and temperature. The optimum acid conversion of 80.8% was observed at an oil-methanol molar ratio of 1:12, amount of catalyst 6 wt% and 120 min of reaction time at 55 °C.

This review is a continuation of the first part, which considered modern trends in the processing of linear alpha olefins to (co)polymers of ethylene, anionic and non-ionic surfactants. Important directions in LAO processing are briefly described: alkylation leading to the formation of linear alkylbenzenes, oligomerization of alpha olefins to poly alpha olefins, sulfation yielding alpha olefin sulfonates, and other bulky processes.

The SARS-CoV-2 spike glycoproteins (SGPs) and human angiotensin converting enzyme 2 (ACE2) are the two key targets for the prevention and treatment of COVID-19. Host cell surface heparan sulfate (HS) is believed to interact with SARS-CoV-2 SGPs to facilitate host cell entry. In the current study, a series of polysaccharides from Saccharina japonica were prepared to investigate the structure-activity relationship on the binding abilities of polysaccharides (oligosaccharides) to pseudotype particles, including SARS-CoV-2 SGPs, and ACE2 using surface plasmon resonance. Sulfated galactofucan (SJ-D-S-H) and glucuronomannan (Gn) displayed strongly inhibited interaction between SARS-CoV-2 SGPs and heparin while showing negligible inhibition of the interaction between SARS-CoV-2 SGPs and ACE2. The IC50 values of SJ-D-S-H and Gn in blocking heparin SGP binding were 27 and 231 nM, respectively. NMR analysis showed that the structure of SJ-D-S-H featured with a backbone of 1, 3-linked α-L-Fucp residues sulfated at C4 and C2/C4 and 1, 3-linked α-L-Fucp residues sulfated at C4 and branched with 1, 6-linked β-D-galacto-biose; Gn had a backbone of alternating 1, 4-linked β-D-GlcAp residues and 1, 2-linked α-D-Manp residues. The sulfated galactofucan and glucuronomannan showed strong binding ability to SARS-CoV-2 SGPs, suggesting that these polysaccharides might be good candidates for preventing and/or treating SARS-CoV-2.

Angiotensin converting enzyme (ACE) is a multifunctional enzyme involved in translation of angiotensin-I (AngI) to vasoconstrictor angiotensin-II (AngII). A sulfated N-acetylglucosamino-glucuronopyranosyl-arabinopyranan characterized as poly-[(2-methoxy-β-arabinopyranosyl)-(1 → 3)-(β-glucurono)-(1 → 4)-(2-acetamido-2-deoxy-3,6-di-O-sulfonato-β-glucopyranose)] was purified and reported first time from the edible portion of Amphioctopus neglectus and evaluated for various pharmacological properties. The polysaccharide exhibited potential ACE attenuation property (IC50 0.11 mg mL−1), whereas molecular docking simulations displayed its efficient binding at the ACE active site with lesser inhibitory constant (Ki) of 17.36 nM and binding energy (−10.59 kcal mol−1). The in-vitro analysis showed that the studied polysacharide attenuated AngII prompted cardiac hypertrophy at 50 μg mL−1 in the cardiomyoblast cells, whereas 48% reduction in cellular surface area with extended viability could be correlated with anti-hypertrophic properties of the studied polysaccharide. The sulfated N-acetylglucosamino-glucuronopyranosyl-arabinopyranan purified from A. neglectus could function as a prospective functional lead against the pathophysiological conditions leading to hypertension.

Water-soluble polysaccharides and pectinic substances from seed pods of Crotalaria alata L. (Uzbekistan) and Crotalaria sp. (India) were studied. The water-soluble polysaccharides were found to dominate over pectinic substances. Galactomannan GM-SP with a Man:Gal ratio of 4.4:1 was isolated from Crotalaria sp. seed pods. Its main chain consisted of 1,4-β-bound polymannans with 1,6-α-bound galactopyranose side residues. Sulfated derivatives of galactomannan from C. alata were prepared. The supramolecular structures of the galactomannan and its sulfated derivative were studied using electron microscopy. The galactomannan sulfated derivative exhibited anticoagulant activity.

Sulfatases constitute a family of enzymes that specifically act in the hydrolytic degradation of sulfated metabolites by removing sulfate monoesters from various substrates, particularly glycolipids and glycosaminoglycans. A common essential feature of all known eukaryotic sulfatases is the posttranslational modification of a critical cysteine residue in their active site by oxidation to formylglycine (FGly), which is mediated by the FGly-generating enzyme in the endoplasmic reticulum and is indispensable for catalytic activity. The majority of the so far described sulfatases localize intracellularly to lysosomes, where they act in different catabolic pathways. Mutations in genes coding for lysosomal sulfatases lead to an accumulation of the sulfated substrates in lysosomes, resulting in impaired cellular function and multisystemic disorders presenting as lysosomal storage diseases, which also cover the mucopolysaccharidoses and metachromatic leukodystrophy. Bioinformatics analysis of the eukaryotic genomes revealed, besides the well described and long known disease-associated sulfatases, additional genes coding for putative enzymes with sulfatases activity, including arylsulfatase G as well as the arylsulfatases H, I, J and K, respectively. In this article, we review current knowledge about lysosomal sulfatases with a special focus on the just recently characterized family members arylsulfatase G and arylsulfatase K.

Flavonoids occupy the largest family of natural products and possess a broad spectrum of health benefits. Their metabolites are sometimes the truly effective molecules in vivo. It is still challenging, however, to unambiguously identify flavonoid metabolites using conventional LC-MS/MS. Herein, we aimed to pursue auxiliary structural clues to m/z values in both MS1 and MS2 spectra through LC coupled to three-dimensional MS (LC-3D MS). MS1, as the first dimension, was in charge of suggesting theoretical molecular formulas, MS2, the as second dimension, was responsible for offering substructures, and exactly, online energy-resolved MS (ER-MS), as the third dimension, provided optimal collision energies (OCEs) that reflected the linkage manners among the substructures. Metabolic characterization of a natural sweet taste modulator, namely, (R)-7,3'-dihydroxy-4'-methoxy-8-methylflavane (DHMMF), was conducted as a proof-of-concept. Extensive efforts, such as full MS1 and MS2 scans on IT-TOF-MS and predictive selected-reaction monitoring mode on Qtrap-MS, were made for in-depth metabolite mining. Seventeen metabolites (M1-M17) were captured from DHMMF-treated biological samples, including 17 (M1-M17), 10 (M4-M9, M11, M13, M14, and M16), and 2 (M5 and M10) metabolites from urine, plasma, and feces, respectively. Their structures were configured by integrating MS1, MS2, and OCE information. Except M10, all metabolites were new compounds. LC-MS/MS-guided chromatographic purification yielded three glucuronyl-conjugated metabolites (M5, M8, and M11), and NMR spectroscopic assays consolidated the structures transmitted from LC-3D MS. Demethylation, glucuronidation, and sulfation occurred as the primary metabolic pathways of DHMMF. Above all, LC-3D MS bridged LC-MS/MS from putatively structural annotation toward confidence-enhanced identification, beyond the metabolite characterization of flavonoids.

Acylated chitosan sulfate (ChS1), a sulfated polysaccharide with high anticoagulant activity, was chemically synthesized and structurally characterized using FT-IR analysis. The beneficial structural properties and high availability of the sulfate group in ChS1 led to greater anticoagulant activity through both the intrinsic and common pathways with antithrombin III (AT III)-mediated inhibition, particularly involving coagulation factors FXa and FIIa. The analysis of the binding affinities using surface plasma resonance found that the equilibrium dissociation constant (KD) of ChS1 for FXa and FIIa in the presence of AT III was 67.4 nM and 112.6 nM, respectively, indicating the stronger interaction of the AT III/ChS1 complex with the ligands and the inhibition of activated FX and FII. The results of amidolytic assays further demonstrated the stronger inhibition of the proteolytic conversion of factor X by the intrinsic FXase complex and of FII by the prothrombinase complex. Molecular docking analysis further validated the protein-ligand interactions of ChS1 with AT III and their binding affinity.

The 3-O sulfate-modified -GlcNS3S6S- monosaccharide in heparin and heparan sulfate glycosaminoglycans (HSGAGs) is a relatively rare yet important modification that facilitates HSGAG-antithrombin binding and subsequent anticoagulant activity. Detecting this modification in complex HSGAG mixtures is a longstanding goal to identify novel 3-O-sulfated HSGAG-protein interactions with biologically significant functions. Tandem mass spectrometry has been applied to HSGAG structural analysis but is limited by the fact that traditional collision-induced dissociation techniques (e.g., CID, HCD) results in extensive sulfate loss prior to generating structurally informative glycosidic and cross-ring fragments. In the present study, we investigated the potential of ultraviolet photodissociation (UVPD) to generate structurally informative fragments from the synthetic heparin mimetic, fondaparinux, under electrospray conditions commensurate with hydrophilic interaction liquid chromatography (HILIC). The two predominant un-adducted precursors, [Fonda-2H+]2- and [Fonda-3H+]3-, were subjected to UVPD, CID, and HCD on an Orbitrap Fusion Lumos Tribrid mass spectrometer and the resulting fragmentation spectra directly compared. Close inspection of the UVPD data identified a unique peak at m/z 417.9425 that matched the Y3/C3 double glycosidic fragment of fondaparinux (i.e., -GlcNS3S6S-). Importantly, the 3-O-sulfated Y3/C3 fragment was generated predominantly from UVPD of the [Fonda-2H+]2- precursor, increased with activation time, and was observable using data-dependent HILIC-MS/MS UVPD analysis of fondaparinux spiked into a semi-complex HSGAG mixture. The discovery of this antithrombin-like 3-O-sulfated fragment provides a potential strategy for screening complex HSGAG mixtures in a data-dependent or data-independent acquisition mode to determine the presence of this therapeutic and biologically significant HSGAG modification. Graphical abstract.

The structures of glycosaminoglycans (GAGs), especially the patterns of modification, are crucial to modulate interactions with various protein targets. It is very challenging to determine the fine structures using liquid chromatography-mass spectrometry (LC-MS) due in large part to the gas-phase sulfate losses upon collisional activation. Previously, our group reported a method for fine structure analysis that required permethylation of the GAG oligosaccharide. However, uncontrolled depolymerization during the permethylation process due to esterification of uronic acid lowers the reliability of the method to resolve structures of GAGs, especially for larger oligosaccharides. Here, we describe a simplified derivatization method using propionylation and desulfation. The oligosaccharides have all hydroxyl and amine groups protected with propionyl groups and then have sulfate groups removed to generate unprotected hydroxyl and amine groups at all sites that were previously sulfated. This derivatized oligosaccharide generates informative fragments during collision-induced dissociation that resolve the original sulfation patterns. This method is demonstrated to enable accurate determination of sulfation patterns of even the highly sulfated pentasaccharide fondaparinux by MS2 and MS3. Using a mixture of dp6 from porcine heparin, we demonstrate that this method allows for structural characterization of complex mixtures, including clear chromatographic separation and sequencing of structural isomers, all at high yields without evidence of depolymerization. This represents a marked improvement in the reliability to structurally characterize GAG oligosaccharides over permethylation-based derivatization schemes.

Sulfated fucan chondroitin sulfate-dominated polysaccharide fraction from low-edible-value sea cucumber may be a good alternative to high-edible-value sea cucumber-derived polysaccharide for application in hypoglycemic functional foods. To evaluate the potential effect of low-edible-value sea cucumber-derived polysaccharide fraction on type 2 diabetes (T2DM), two sulfated fucan/fucosylated chondroitin sulfate-dominated polysaccharide fractions screening from 10 global commercial low-edible-value sea cucumber species were investigated to identify their anti-diabetics efficacies using a high-fat diet and streptozotocin-induced T2DM rat model. Sulfated fucan-dominated polysaccharide fraction from Thelenota ananas and fucosylated chondroitin sulfate-dominated polysaccharide fraction from Cucumaria frondosa ameliorated hyperglycemia, restored hypertriglyceridemia and hypercholesterolemia, decreased inflammatory status and oxidative stress, protected against liver injury, as well as improved insulin resistance and promoted accumulation of hepatic glycogen by activating IRS/PI3K/AKT signaling and regulating GSK-3β gene expression in T2DM rats. The current findings provide an available strategy for the commercialization of sea cucumber polysaccharide based-hypoglycemic functional food.

In this study, a crude and purified polysaccharide from Cyclocarya paliurus (CPP, CPP0.05) were performed with chlorosulfonic acid-pyridine (CSA-Pyr) method to obtain sulfated derivatives (S-CPP, S-CPP0.05). After comparatively investigating, characterization results showed that the modifications were successful. Polysaccharides were used to culture mouse bone marrow-derived dendritic cells (BM-DCs) to evaluate their immunomodulatory activity and explore mechanism. The functional activity of CPP was significantly stronger than that of the purified polysaccharide CPP0.05. Meanwhile, S-CPP showed stronger immunomodulatory activity than CPP through determination of cytokine expression levels. We found that p-JNK, p-p38MAPK and NF-κB p65 proteins were significantly increased by stimulus of CPP and S-CPP, blocking TLR2/4 could significantly decreased proteins above which proved that immune regulation effect of CPP and S-CPP on DCs was performed via MAPK and NF-κB signaling pathways by triggering TLR2/4. S-CPP could serve as potential immunomodulatory agents used as complementary medicine or functional foods.

Glycosaminoglycans (GAGs) are a class of linear polysaccharides, consisting of alternating disaccharide sequences of uronic acid and hexosamines (or galactose) with and without sulfation. They can interact with various proteins, such as growth factors, receptors and cell adhesion molecules, endowing these with various biological and pharmacological activities. Such activities make GAGs useful in health care products and medicines. Currently, all GAGs, with the exception of hyaluronan, are produced by extraction from animal tissues. However, limited availability, poor control of animal tissues, impurities, viruses, prions, endotoxins, contamination and other problems have increased the interest in new approaches for GAG production. These new approaches include GAGs production by chemical synthesis, chemoenzymatic synthesis and metabolic engineering. One chemically synthesized heparin pentasaccharide, fondaparinux sodium, is in clinical use. Mostly, hyaluronan today is prepared by microbial fermentation, largely replacing hyaluronan from rooster comb. The recent gram scale chemoenzymatic synthesis of a heparin dodecasaccharide suggests its potential to replace currently used animal-sourced low molecular weight heparin (LMWH). Despite these considerable successes, such high-tech approaches still cannot meet worldwide demands for GAGs. This review gives a brief introduction on the manufacturing of unfractionated and low molecular weight heparins, the chemical synthesis and chemoenzymatic synthesis of GAGs and focuses on the progress in the bioengineered preparation of GAGs, particularly heparin.

A successful synthesis of O-sulfated syndecan-1-like (Q23-E120) glyco-polypeptide was accomplished. The synthesis features the integration of an O-sulfated carbohydrate-bearing glycopeptide cassette with efficient protein ligation strategies, overcoming the acid lability of carbohydrate sulfates as a major hurdle in solid-phase peptide synthesis. Crucial to the synthesis is the microwave-assisted Ag(I) ligation, which afforded the ligation product in improved overall yield. This O-sulfated syndecan-1 (Q23-E120) is the longest O-sulfated glyco-polypeptide prepared to date.

Heparin binds to and activates antithrombin (AT) through a specific pentasaccharide sequence, in which a trisaccharide subsite, containing glucuronic acid (GlcA), has been considered as the initiator in the recognition of the polysaccharide by the protein. Recently it was suggested that sulfated iduronic acid (IdoA2S) could replace this "canonical" GlcA. Indeed, a heparin octasaccharidic sequence obtained by chemoenzymatic synthesis, in which GlcA is replaced with IdoA2S, has been found to similarly bind to and activate antithrombin. By using saturation-transfer-difference (STD) NMR, NOEs, transferred NOEs (tr-NOEs) NMR and molecular dynamics, we show that, upon binding to AT, this IdoA2S unit develops comparable interactions with AT as GlcA. Interestingly, two IdoA2S units, both present in a 1 C4 -2 S0 equilibrium in the unbound saccharide, shift to full 2 S0 and full 1 C4 upon binding to antithrombin, providing the best illustration of the critical role of iduronic acid conformational flexibility in biological systems.

In this study, ginger polysaccharide (GP), ginger polysaccharide 1 (GP1), and ginger polysaccharide 2 (GP2) from ginger were firstly modified by sulfation. Fourier transform infrared, and nuclear magnetic resonance spectra investigation of sulfated ginger polysaccharide (SGP), sulfated ginger polysaccharide 1 (SGP1), and sulfated ginger polysaccharide 2 (SGP2) revealed that the sulfation successfully occurred with the characteristic absorption peak of polysaccharide. Congo red experiment showed that triple helical structure existed in SGP and SGP1, but random coils existed in SGP2. SGP, SGP1, and SGP2 all showed a rough and rugged surface with plenty of small pores. The blood clotting time of SGP2 or SGP at 2 mg/mL in activated partial thromboplastin time (APTT) assay was 41.42 or 38.01 s, respectively, which were approximately 1.33- and 1.22-fold longer than that of the physiological saline. Compared to the saline control group, prothrombin time (PT) was increased by 1.22-fold with the addition of GP at 2 mg/mL. However, no clotting inhibition phenomenon was observed in thrombin time test even at the concentrations that APTT and PT were obviously prolonged. It indicated that GP2, SGP2, and SGP inhibited the intrinsic pathway of coagulation, but GP inhibited both the intrinsic and extrinsic pathways of coagulation. Hence, ginger polysaccharides might be used as anticoagulants and therapeutic reagents for thrombosis.

Three polysaccharides (SH-1, SH-2 and SH-3) were purified from a brown macroalgea, Sargassum hemiphyllum. The autohydrolysis products from each polysaccharide were separated to three fractions (S fractions as oligomers, L fractions as low molecular weight polysaccharides and H fractions as high molecular weight polysaccharides). Mass spectroscopy of S fractions (SH-1-S, SH-2-S and SH-3-S) showed that these three polymers all contained short stretches of sulfated fucose. The structures of L fractions (SH-1-L, SH-2-L and SH-3-L) were determined by nuclear magnetic resonance (NMR). SH-1-L was composed of two units, unit A (sulfated galactofucan) and unit B (sulfated xylo-glucuronomannan). Unit A contained a backbone of (1, 6-linked β-D-Gal) n1, (1, 3-linked 4-sulfated α-L-Fuc) n2, (1, 3-linked 2, 4-di-sulfated α-L-Fuc) n3, (1, 4-linked α-L-Fuc) n4 and (1, 3-linked β-D-Gal) n5, accompanied by some branches, such as sulfated fuco-oligomers, sulfated galacto-oligomers or sulfated galacto-fuco-oligomers. And unit B consisted of alternating 1, 4-linked β-D-glucuronic acid (GlcA) and 1, 2-linked α-D-mannose (Man) with the Man residues randomly sulfated at C6 or branched with xylose (Xyl) at C3. Both SH-2-L and SH-3-L were composed of unit A and their difference was attributed to the ratio of n1: n2: n3: n4: n5. Based on monosaccharide analysis, we hypothesize that both SH-1-H and SH-2-H contained unit A and unit B while SH-3-H had a structure similar to SH-3-L. An assessment of anti-complement activities showed that the sulfated galactofucan had higher activities than sulfated galacto-fuco-xylo-glucuronomannan. These results suggest that the sulfated galactofucans might be a good candidate for anti-complement drugs.