Chemical characteristic of an anticoagulant-active sulfated polysaccharide from Enteromorpha clathrata

Ion-Exchange Resin/Carrageenan-Copper-Based Nanocomposite: Artificial Neural Network, Advanced Thermodynamic Profiling, and Anticoagulant Studies

Carrageenan (CG) and ion exchange resins (IERs) are better metal chelators. Kappa (κ) CG and IERs were synthesized and subjected to copper ion (Cu2+) adsorption to obtain DMSCH/κ-Cu, DC20H/κ-Cu, and IRP69H/κ-Cu nanocomposites (NCs). The NCs were studied using statistical physics formalism (SPF) at 315-375 K and a multilayer perceptron with five input nodes. The percentage of Cu2+ uptake efficiency was used as an outcome variable. Via the grand canonical ensemble, SPF gives models for both monolayer and multilayer sorption layers. For in vitro anticoagulant activity (ACA), the activated partial thromboplastin time were calculated using 100 μL of rabbit plasma incubated at 37 °C. After 2 min, 100 L of 0.025 M CaCl2 was added, and the clotting time was recorded for each group (n = 6). The results demonstrated that the key covariables for the adsorption process were pH and concentration. The results of artificial neural network models were comparable with the experimental findings. The error rates varied between 4.3 and 1.0%. The prediction analysis results ranged from 43.6 to 89.2. The ΔG and ΔS values for IRP69H/κ-Cu obtained were -18.91 and -16.32 and 26.21 and 22.74 kJ/mol for the temperatures 315 and 345 K, respectively. Adsorbate species were perpendicular to the adsorbent surfaces, notwithstanding the apparent importance of macro- and micropore volumes. These adsorbents typically fluctuate with temperature changes and contain one or more layers of sorption. Negative and positive sorption energies correspond to endothermic and exothermic processes. The biosorption energy (E1 and E2) values in this experiment have a value of less than 23 kJ mol-1. Complex SPF models' energy distributions validate surface properties and interactions with adsorbates. At a concentration of 100 μg/mL, DC20H/κ-Cu2+ exhibited an ACA of only 8 s. These NCs demonstrated better greater ACA with the order DC20H/κ < DMSCH/κ < IRP69H/κ. More research is needed to rule out the chemical processes behind the ACA of CG/IER-Cu NCs.

Effects of natural products on functional constipation: analysis of active ingredient and mechanism

Constipation is a prevalent clinical ailment of the gastrointestinal system, yet its pathogenesis remains ambiguous. Despite the availability of numerous treatment modalities, they are insufficient in resolving the issue for patients. This work conducted a comprehensive review of the existing literature pertaining to the utilization of natural products for the treatment of constipation, with a focus on the efficacy of natural products in treating constipation, and to provide a comprehensive summary of their underlying mechanisms of action. Upon conducting a thorough review of the extant literature, we found that natural products can effectively treat constipation as modern synthetic drugs and compounded drugs with acetylcholinesterase (AChE) effects, rich in fiber and mucus, and the effects of increasing the tension of the ileum and gastrointestinal tract muscle, mediating signaling pathways, cytokine, excitability of the smooth muscle of the gastrointestinal tract, and regulating the homeostasis of intestinal flora. However, there is a wide variety of natural products, and there are still relatively few studies; the composition of natural products is complex, and the mechanism of action of natural products cannot be clarified. In the future, we need to further improve the detailed mechanism of natural products for the treatment of constipation.

Flash extraction of ulvan polysaccharides from marine green macroalga Ulva linza and evaluation of its antioxidant and gut microbiota modulation activities

In this study, flash extraction was used to rapidly extract water-soluble polysaccharides from Ulva linza. The optimal extraction process for the flash extraction was determined by Box-Behnken design with extraction temperature 80 °C, extraction time 117 s, liquid-solid ratio 46:1 (mL/g) and a corresponding yield of 18.5 %. The crude Ulva linza polysaccharides (CULP) were subsequently isolated by chromatography technology to obtain purified Ulva linza polysaccharide (ULP) and characterized by monosaccharide composition and molecular weight determination analysis. Furthermore, the antioxidant bioactivity of ULP was studied and the results revealed that it had a good scavenging effect on DPPH, ABTS and OH, with IC50 values of 149.2 μg/mL, 252.5 μg/mL and 1073 μg/mL, respectively. After in vitro fermentation by human fecal microbiota, the pH value of fermentation culture significantly decreased to 5.06, suggesting that ULP could be hydrolyzed and utilized by gut microbiota. The abundance of beneficial bacteria including Bacteroides, Parabacteroides and Faecalibacterium was improved. Meanwhile, the relative abundance of Prevotella, Blautia and Ruminococcus was decreased, and the low ratio of these organisms might reveal positive effects on maintaining the balance of gut microbial biodiversity. These results suggested that the composition of the human gut microbiota could be modulated by ULP, and ULP might possess the potential to maintain gut homeostasis and improve human intestinal health.

Structure-activity relationships of bioactive polysaccharides extracted from macroalgae towards biomedical application: A review

Macroalgae are valuable and structurally diverse sources of bioactive compounds among marine resources. The cell walls of macroalgae are rich in polysaccharides which exhibit a wide range of biological activities, such as anticoagulant, antioxidant, antiviral, anti-inflammatory, immunomodulatory, and antitumor activities. Macroalgae polysaccharides (MPs) have been recognized as one of the most promising candidates in the biomedical field. However, the structure-activity relationships of bioactive polysaccharides extracted from macroalgae are complex and influenced by various factors. A clear understanding of these relationships is indeed critical in developing effective biomedical applications with MPs. In line with these challenges and knowledge gaps, this paper summarized the structural characteristics of marine MPs from different sources and relevant functional and bioactive properties and particularly highlighted those essential effects of the structure-bioactivity relationships presented in biomedical applications. This review not only focused on elucidating a particular action mechanism of MPs, but also intended to identify a novel or potential application of these valued compounds in the biomedical field in terms of their structural characteristics. In the last, the challenges and prospects of MPs in structure-bioactivity elucidation were further discussed and predicted, where they were emphasized on exploring modern biotechnology approaches potentially applied to expand their promising biomedical applications.

Research progress on ginger polysaccharides: extraction, purification and structure-bioactivity relationship

Ginger is a widespread source of herbal medicine and traditional spices. Among its various bioactive components, ginger polysaccharides (GPs) have attracted the attention of researchers worldwide because of their significant bioactivity. Recent studies have demonstrated the antioxidant, antitumour, anti-inflammatory, immunomodulatory, hypoglycaemic, cough suppressant and thrombotic anticoagulant effects of GPs. However, the structure-bioactivity relationship of GPs has yet to be comprehensively investigated. This review aims to explore all the current published studies on GPs. It further examines various aspects, including the extraction and purification methods, structure, bioactivity, application and structure-bioactivity relationship of GPs. Thus, this review intends to provide a reference for future GP-related research and development.

Optimization and Physicochemical Characterization of Polysaccharide Purified from Sonneratia caseolaris Mangrove Leaves: a Potential Antioxidant and Antibiofilm Agent

The Box-Behnken design was applied to determine the optimal parameters of the extraction condition by using the response surface methodology (RSM) from the leaves of Sonneratia caseolaris L. The result indicates the best-optimized conditions used for the extraction of polysaccharides at 84.02 °C temperature, 3.12 h time, and 27.31 mL/g for the water-to-material ratio. The maximum experimental yield of 8.81 ± 0.09% was obtained which is in agreement with the predicted value of 8.79%. Thereafter, low molecular weight polysaccharide (SCLP) was separated after sequentially being purified through column chromatography with a relative molecular weight of 3.74 kDa. The physicochemical properties were evaluated by characterization techniques such as FT-IR spectra, NMR spectrum, and SEM analysis. RP-HPLC analysis confirmed that SCLP was a heteropolysaccharide, majorly comprising rhamnose (28.25%), and xylose (27.17%) residues, followed by mannose (18.90%), and galactose (17.17%), respectively. Thermal analysis (TGA-DSC) results showed that SCLP is a highly thermostable polymer with a degradation temperature of 361.63 °C. X-ray diffraction patterns and tertiary structure analyses indicate that SCLP had a semi-crystalline polymer having a triple-helical configuration. Moreover, SCLP displayed potential antibiofilm ability for all the tested pathogens while stronger activity against Klebsiella pneumoniae and Pseudomonas aeruginosa. In addition, SCLP has potential in vitro antioxidant activity on DPPH, ABTS radical, superoxide, and Fe2+ chelating. These findings indicate that the polysaccharide has potentially been used in functional food, cosmetics, and pharmacological industries.

Artificial switches induce the bespoke production of functional compounds in marine microalgae Chlorella by neutralizing CO2

To improve the CO2 tolerance of a marine microalga Chlorella sp. of which the production capacity has been demonstrated industrially, a mutant library was created and a strain hct53 was screened. Compared to the parental strain, hct53 shows a high CO2 capture capacity, while starch biosynthesis is compromised, with increases in health beneficial metabolites and antioxidant capacity. Global gene expression and genome-wide mutation distribution revealed that transcript choreography was concomitant with more active CO2 sequestration, an increase in the lipid synthesis, and a decrease in the starch and protein synthesis. These results suggest that artificial trait improvement via mutagenesis, couple with multiomics analysis, helps discover genetic switches that induce the bespoke conversion of carbon flow from "redundant metabolites" to valuable ones for functional food.

Stimuli-Responsive Polysaccharide Hydrogels and Their Composites for Wound Healing Applications

There is a growing concern about wound care, since traditional dressings such as bandages and sutures can no longer meet existing needs. To address the demanding requirements, naturally occurring polymers have been extensively exploited for use in modern wound management. Polysaccharides, being the most abundant biopolymers, have some distinct characteristics, including biocompatibility and biodegradability, which render them ideal candidates for wound healing applications. Combining them with inorganic and organic moieties can produce effective multifunctional composites with the desired mechanical properties, high wound healing efficiencies and excellent antibacterial behavior. Recent research endeavors focus on the development of stimuli-responsive polysaccharide composites for biomedical applications. Polysaccharide composites, being sensitive to the local environment, such as changes of the solution temperature, pH, etc., can sense and react to the wound conditions, thus promoting an effective interaction with the wound. This review highlights the recent advances in stimuli-responsive polysaccharide hydrogels and their composites for use in wound healing applications. The synthetic approaches, physical, chemical, and biochemical properties as well as their function in wound healing will be discussed.

Structure and Anticoagulant Activity of a Galactofuranose-Containing Sulfated Polysaccharide from the Green Seaweed, Codium isthmocladum

A water-soluble sulfated polysaccharide, F2-1, was obtained from the marine green alga, Codium isthmocladum, using ion-exchange and size-exclusion chromatography. Structure analysis showed that the F2-1 was a sulfated arabinan comprising Ara, Rha, Man, Gal, and Xyl with an 18% sulfate content and a molecular weight of 100 kDa. Methylation analysis combined with desulfation, GC-MS, IR, and NMR spectroscopy showed that the backbone of F2-1 was →4)-β-L-Arap(1→ residue. Its 2-O and/or 3-O positions showed sulfate modification; additionally, the 2-O or 3-O position showed branch points. The side chains were composed of →5)-β-D-Galf, (1→2,6)-β-D-Galf(1→, (1→2)-β-L-Rhap4S, →4)-α-D-Glcp(1→, and terminal α-D-Galp(1→ and β-D-Xylp(1→. Polysaccharides containing β-D-galactofuranose are rarely found in seaweed. F2-1 exhibited significant anticoagulant activity in vitro. Our findings suggested that the green-tide alga, Codium isthmocladum, can be considered as a useful resource for bioactive polysaccharides.

Antidiabetic-activity sulfated polysaccharide from Chaetomorpha linum: Characteristics of its structure and effects on oxidative stress and mitochondrial function

A water-soluble polysaccharide from the green alga Chaetomorpha linum, designated CHS2, was obtained by water extraction, preparative anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that CHS2 was a sulfated rhamnogalactoarabinan, and its backbone was mainly constituted by 4-linked and 3,4-linked β-l-arabinopyranose with sulfate groups at C-2/C-3 of 4-linked β-l-arabinopyranose. The branching contained 4-linked, 6-linked β-d-galactopyranose and terminal rhamnose residues. Based on the inhibition of human islet amyloid polypeptide (hIAPP) aggregation and morphology change of hIAPP aggregates in in vitro tests, it was proved that CHS2 effectively inhibited the hIAPP aggregation and possessed strong antidiabetic activity. CHS2 was nearly no toxicity in NIT-1 cells and could attenuate hIAPP-induced cytotoxicity. CHS2 may significantly reduce the generation of intracellular reactive oxygen species and hIAPP aggregation-induced oxidative stress in NIT-1 cells. CHS2 was co-localized with mitochondria, and largely protected mitochondria function from hIAPP aggregation-induced damage through stabilizing mitochondrial membrane potential and enhancing the mitochondrial complex I, II or III activity and ATP level. The data demonstrated that CHS2 could have potential prospect to become an antidiabetic drug for type 2 diabetes mellitus treatment.

Polyphenols extracted from Enteromorpha clathrata alleviates inflammation in lipopolysaccharide-induced RAW 264.7 cells by inhibiting the MAPKs/NF-κB signaling pathways

ETHNOPHARMACOLOGY RELEVANCE

Enteromorpha has long been recorded in traditional Chinese medicine, with cholesterol-lowering, anti-cancer, anti-inflammatory and antibacterial effects. Recently, we extracted the polyphenol-enriched fraction from Enteromorpha clathrata (E. clathrata) by ethyl acetate (ECPs), and isolated six individual polyphenols from ECPs via high-speed counter-current chromatography (HSCCC) with high-performance liquid chromatography (HPLC).

AIM OF THE STUDY

In this study, we explored the anti-inflammatory activity and underlying mechanism of ECPs in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages.

MATERIALS AND METHODS

ECPs and the six polyphenols were used for nitric oxide (NO) assay to identify the components with potent inflammation inhibitory effect. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time PCR (qPCR), flow cytometry, and Western blot analysis were applied to further investigate their anti-inflammatory effects and underlying mechanism in LPS-stimulated RAW264.7 cells.

RESULTS

ECPs and the three individual polyphenols, including (-)-epicatechin, epigallocatechin-3-O-gallate and (-)-epicatechin-3-O-gallate, showed in vitro immunosuppressive activity by altering the cell biology at the gene, protein and functional levels in a dose- and species-dependent manner. Their anti-inflammatory effects were achieved by inhibiting LPS-induced production of nitric oxide and its upstream enzyme inducible nitric oxide synthase (iNOS), the pro-inflammatory cytokines including interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), as well as the phagocytotic capacity, without cytotoxicity. The mechanism study further revealed that these anti-inflammatory properties were, at least partly, attributed to the suppressed activation of nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signaling pathways.

CONCLUSIONS

These findings indicated for the first time the correlation between the anti-inflammatory activity of ECPs and NF-κB and MAPK signaling pathways, suggesting that polyphenol-enriched organic fraction of E. clathrata could be potential candidate as therapeutic agent for treating inflammatory diseases.

Ulva (Enteromorpha) Polysaccharides and Oligosaccharides: A Potential Functional Food Source from Green-Tide-Forming Macroalgae

The high-valued utilization of Ulva (previously known as Enteromorpha) bioresources has drawn increasing attention due to the periodic blooms of world-wide green tide. The polysaccharide is the main functional component of Ulva and exhibits various physiological activities. The Ulva oligosaccharide as the degradation product of polysaccharide not only possesses some obvious activities, but also possesses excellent solubility and bioavailability. Both Ulva polysaccharides and oligosaccharides hold promising potential in the food industry as new functional foods or food additives. Studies on Ulva polysaccharides and oligosaccharides are increasing and have been the focus of the marine bioresources field. However, the comprehensive review of this topic is still rare and do not cover the recent advances of the structure, isolation, preparation, activity and applications of Ulva polysaccharides and oligosaccharides. This review systematically summarizes and discusses the recent advances of chemical composition, extraction, purification, structure, and activity of Ulva polysaccharides as well as oligosaccharides. In addition, the potential applications as new functional food and food additives have also been considered, and these will definitely expand the applications of Ulva oligosaccharides in the food and medical fields.

Ecological and evolutionary diversification of sulphated polysaccharides in diverse photosynthetic lineages: A review

Sulphated polysaccharides (SPs) are carbohydrate macromolecules with sulphate esters that are found among marine algae, seagrasses, mangroves and some terrestrial plants. The sulphate concentration in the ocean (28 mM) since ancient time could have driven the production of SPs in marine algae. SPs have a gelatinous property that can protect marine algae against desiccation and salinity stress. Agar and carrageenan are red algal SPs that are widely used as gelling agents in the food and pharmaceutical industries. The information on the SPs from freshwater and land plants are limited. In this review, we reviewed the taxonomic distribution and composition of SPs in different photosynthetic lineages, and explored the association of SP production in these diversified photosynthetic organisms with evolution history and environmental stresses. We also reviewed the genes/proteins involved in SP biosynthesis. Insights into SP biosynthetic machinery may shed light on the evolution that accompanied adaptation to life on earth.

Advance research in biomedical applications on marine sulfated polysaccharide

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" (SPs). The considerable amount of SP exists in the algae in the form of fucans, fucoidans, carrageenans, ulvan, etc. Major function of SPs is to act as a defensive lattice towards the infective organism. All SPs 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.

Recent Advancements and Future Perspectives of Microalgae-Derived Pharmaceuticals

Microalgal cells serve as solar-powered factories that produce pharmaceuticals, recombinant proteins (vaccines and drugs), and valuable natural byproducts that possess medicinal properties. The main advantages of microalgae as cell factories can be summarized as follows: they are fueled by photosynthesis, are carbon dioxide-neutral, have rapid growth rates, are robust, have low-cost cultivation, are easily scalable, pose no risk of human pathogenic contamination, and their valuable natural byproducts can be further processed. Despite their potential, there are many technical hurdles that need to be overcome before the commercial production of microalgal pharmaceuticals, and extensive studies regarding their impact on human health must still be conducted and the results evaluated. Clearly, much work remains to be done before microalgae can be used in the large-scale commercial production of pharmaceuticals. This review focuses on recent advancements in microalgal biotechnology and its future perspectives.

Recent advances in industrial applications of seaweeds

Seaweeds have been generally utilized as food and alternative medicine in different countries. They are specifically used as a raw material for wine, cheese, soup, tea, noodles, etc. In addition, seaweeds are potentially good resources of protein, vitamins, minerals, carbohydrates, essential fatty acids and dietary fiber. The quality and quantity of biologically active compounds in seaweeds depend on season and harvesting period, seaweed geolocation as well as ecological factors. Seaweeds or their extracts have been studied as innovative sources for a variety of bioactive compounds such as polyunsaturated fatty acids, polyphenols, carrageenan, fucoidan, etc. These secondary metabolites have been shown to have antioxidant, antimicrobial, antiviral, anticancer, antidiabetic, anti-inflammatory, anti-aging, anti-obesity and anti-tumour properties. They have been used in pharmaceutical/medicine, and food industries since bioactive compounds from seaweeds are regarded as safe and natural. Therefore, this article provides up-to-date information on the applications of seaweed in different industries such as pharmaceutical, biomedical, cosmetics, dermatology and agriculture. Further studies on innovative extraction methods, safety issue and health-promoting properties should be reconsidered. Moreover, the details of the molecular mechanisms of seaweeds and their bioactive compounds for physiological activities are to be clearly elucidated.

Steam explosion pretreatment of Achyranthis bidentatae radix: Modified polysaccharide and its antioxidant activities

Steam explosion technology was employed for the pretreatment of Achyranthis bidentatae radix (ABR) under mild conditions, followed by the polysaccharide extraction. An increase in the extraction yield and uronic acid content of crude polysaccharide were detected, along with a decrease in the protein content induced by the steam explosion. The monosaccharide analysis showed the main compositional modification of polysaccharide is the increase in the proportion of galacturonic acid, galactose, and arabinose. It is consistent with the discriminant analysis of the FT-IR and UV-vis spectra. These structural modifications of crude polysaccharide caused by the steam explosion pretreatment (SEP) resulted in the significant increases in their antioxidant activities in vitro and in vivo. Strong correlations were observed between the pretreatment conditions and the changes in the structural characteristics and antioxidant activities of Achyranthis bidentatae radix polysaccharides (ABPS).

Extraction Techniques, Biological Activities and Health Benefits of Marine Algae Enteromorpha prolifera Polysaccharide

There is increasing interest in the use of marine algae as functional food additives for improving human health. Enteromorpha (Ulva) prolifera (E. prolifera) is a seaweed green alga (Chlorophyta) that contains many bioactive compounds, of which polysaccharide is the main component. With the advancement of technology in the methods of extraction and analysis, recent studies in in vitro and animals model showed that polysaccharides derived from E. prolifera exert various biological activities, such as gut microbiota modulation, immunomodulation, antioxidant, antidiabetic, antimicrobial, and hypolipidemic. Research evidence has shown that methods of extraction and molecular modification, such as degradation, carboxymethylation, and sulfonation could alter the biological activities of polysaccharides. Therefore, in this review, we discussed the different extraction techniques, structural-activity relationship, and health benefits of sulfated polysaccharides derived from E. prolifera, and suggested future research avenues. This review helps to advance the extraction techniques and promote the application of marine algae polysaccharides as functional food and therapeutic agent.

Dietary Polysaccharide from Enteromorpha clathrata Attenuates Obesity and Increases the Intestinal Abundance of Butyrate-Producing Bacterium, Eubacterium xylanophilum, in Mice Fed a High-Fat Diet

Previous studies have suggested that polysaccharide from Enteromorpha clathrata (ECP) could be used as a potential prebiotic to treat dysbiosis-associated diseases. However, whether it has any therapeutic effects on obesity has not been investigated. In the present study, we explored the anti-obesity effect of ECP and illustrated that it can significantly reduce the body weight and decrease the serum levels of triacylglycerol and cholesterol in high-fat diet (HFD)-fed mice. As revealed by 16S rRNA high-throughput sequencing and bioinformatic analysis, HFD remarkably changed the composition of the gut microbiota and promoted the growth of opportunistic pathogens such as Mucispirillum, Desulfobacterota and Alphaproteobacteria in obese mice. Interestingly, ECP improved intestinal dysbiosis caused by HFD and reshaped the structure of the gut microbiota in diseased mice by increasing the abundance of butyrate-producing bacterium, Eubacterium xylanophilum, in the gut. Altogether, we demonstrate for the first time an anti-obesity effect of ECP and shed new light into its therapeutic mechanisms from the perspective of gut microbiota. Our study will pave the way for the development of ECP as new prebiotic for the treatment of obesity and its associated disorders.

A Comprehensive Review on Ulvan Based Hydrogel and Its Biomedical Applications

Ulvan is a natural sulfated polysaccharide obtained from marine green algae composed of 3-sulfated rhamnoglucuronan as the main component. It has a unique chemical structure that rich of L-rhamnosa, D-glucuronic acid, and L-iduronic acid. Ulvan has a similar structure to glycosaminoglycans (GAGs) in mammals including chondroitin sulfate, dermatan sulfate, and heparan sulfate that has broad range applications for many years. Here, we provide an overview of ulvan based hydrogels for biomedical applications. Hydrogels are one of ulvan advances in polymer science for application in drug delivery, tissue engineering, and wound healing. This review presented an overview about functional information of ulvan based hydrogels and the promising potential in biomedicals collected from published papers in Scopus, PubMed, and Google Scholar. Other important aspects concerning properties, hydrogel-forming mechanisms, and ulvan based hydrogel developments were reported as well. As conclusion, ulvan showed interesting properties in forming hydrogels and promising advances in biomedical applications.

Are all ulvans equal? A comparative assessment of the chemical and gelling properties of ulvan from blade and filamentous Ulva

Green seaweeds of the genus Ulva are rich in the bioactive sulfated polysaccharide ulvan. Herein we characterise ulvan from Ulva species collected from the Bay of Plenty, Aotearoa New Zealand. Using standardised procedures, we quantified, characterised, and compared ulvans from blade (U. australis, U. rigida, U. sp. B, and Ulva sp.) and filamentous (U. flexuosa, U. compressa, U. prolifera, and U. ralfsii) Ulva species. There were distinct differences in composition and structure of ulvans between morphologies. Ulvan isolated from blade species had higher yields (14.0-19.3 %) and iduronic acid content (IdoA = 7-18 mol%), and lower molecular weight (Mw = 190-254 kDa) and storage moduli (G' = 0.1-6.6 Pa) than filamentous species (yield = 7.2-14.6 %; IdoA = 4-7 mol%; Mw = 260-406 kDa; G' = 22.7-74.2 Pa). These results highlight the variability of the physicochemical properties of ulvan from different Ulva sources, and identifies a morphology-based division within the genus Ulva.

Characterization of a polysaccharide from the medicinal lichen, Usnea longissima, and its immunostimulating effect in vivo

A polysaccharide, CSL-0.1, was isolated from the medicinal lichen, Usnea longissima. CSL-0.1 was a neutral rhamnose-containing glucogalactomannan with a molecular weight of 7.86 × 104 Da. The polysaccharide had a core mannan structure with (1 → 6)-α-d-Manp units as the main chain and was substituted at the O-2 positions with side chains containing (1 → 2)-α-d-Manp residue, [3)-α-Glcp(1 → 4)-α-Glcp(1→] and 6-O-substituted β-d-Galf units. 2-O- and 2,3-di-O-substituted Rhap units. The effects of CSL-0.1 on intestinal immunity and antioxidant activity were evaluated. CSL-0.1 increased the spleen and thymus indices in a dose-dependent manner and conferred immunomodulation on reversing the Th1/Th2-related cytokine imbalance in cyclophosphamide (CP)-induced immunosuppressed mice. CSL-0.1 could also enhance the levels of secretory immunoglobulin A in CP-injected mice. Additionally, the antioxidant levels in the liver and intestine of the mice were increased 20%-50% after intragastric injection by CSL-0.1.

Natural Antioxidants in Anemia Treatment

Anemia, characterized by a decrease of the hemoglobin level in the blood and a reduction in carrying capacity of oxygen, is a major public health problem which affects people of all ages. The methods used to treat anemia are blood transfusion and oral administration of iron-based supplements, but these treatments are associated with a number of side effects, such as nausea, vomiting, constipation, and stomach pain, which limit its long-term use. In addition, oral iron supplements are poorly absorbed in the intestinal tract, due to overexpression of hepcidin, a peptide hormone that plays a central role in iron homeostasis. In this review, we conducted an analysis of the literature on biologically active compounds and plant extracts used in the treatment of various types of anemia. The purpose of this review is to provide up-to-date information on the use of these compounds and plant extracts, in order to explore their therapeutic potential. The advantage of using them is that they are available from natural resources and can be used as main, alternative, or adjuvant therapies in many diseases, such as various types of anemia.

Sulfation, structural analysis, and anticoagulant bioactivity of ginger polysaccharides

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.

Ulvan lyase assisted structural characterization of ulvan from Ulva pertusa and its antiviral activity against vesicular stomatitis virus

Marine green algae are valuable sources of diverse health-promoting bioactive components. Ulvan is suitable for biological applications due to its unique structure and numerous bioactivities. Here, the complex structure of ulvan from Ulva pertusa was analyzed using specific ulvan lyase degradation, MS, and NMR detection. Its structure mainly consists of →4)-β-d-GlcA-(1 → 4)-α-l-Rha3S-(1 → and →4)-β-d-Xyl-(1 → 4)-α-l-Rha3S-(1 → repeating units. Small amounts of →4)-α-l-IdoA-(1 → 4)-α-l-Rha3S-(1 → unit also exist. In addition, a minor number of branches, a single GlcA, and a long branch containing GlcA-Glc were linked to Rha3S. The antiviral activity of the ulvan and its degraded fragments were further investigated. Ulvan (1068.2 kDa) and ulvan-F1 (38.5 kDa) with relatively high molecular weight showed potency of inhibiting the infection and replication of vesicular stomatitis virus (VSV) at 100 μg/mL, the inhibition rate of VSV replication was 40.75% and 40.13%, respectively. These results indicated that ulvan has potential as a functional agent.

Structure characterization and anticoagulant activity of a novel polysaccharide from Leonurus artemisia (Laur.) S. Y. Hu F

An acidic polysaccharide, named LAP-1, was extracted and isolated from Leonurus artemisia (Laur.), and was further purified with ion exchange chromatography and gel chromatography. The extraction conditions of the crude polysaccharides were optimized by single-factor experiments and response surface methodology. The primary structure of the purified polysaccharide was measured by FT-IR, GC-MS, and NMR. The results showed that LAP-1 was mainly composed of galacturonic acid (GalA), mannose (Man), xylose (Xyl), rhamnose (Rha), arabinose (Ara), glucose (Glc), galactose (Gal), fucose (Fuc), ribose (Rib), and glucuronic acid (GlcA) in the molar ratio of 8.74 : 3.45 : 1.02 : 1 : 2.11 : 5.60 : 4.73 : 1.08 : 1.09 : 1.47. Primary structure analysis results indicated that LAP-1 contained characteristic glycosyl linkages such as →1)-α-d-Manp, →1)-α-d-Glcp, →1)-α-d-Arap-(2→, →1)-β-d-Galp-(3→, →1)-β-d-Manp-(4→, →1)-β-d-Galp-(4→, →1)-β-d-Glcp-(4→, →1)-β-d-GalAp-(4→, →1)-β-d-GlcAp-(4→, →1)-β-d-Manp-(4,6→, →1)-β-d-Manp-(3,4→. The M_w/M_n (PDI), M_n, M_z and M_w of LAP-1 were determined to be 1.423, 6.979 × 10³ g mol⁻¹, 1.409 × 10⁴ g mol⁻¹, and 9.930 × 10³ g mol⁻¹ by HPSEC-MALLS-RID and DLS. SEM, TEM and AFM results indicated that LAP-1 was a highly branched structure. LAP-1 showed mild anticoagulant activity, low toxicity, and less spontaneous bleeding compared with heparin sodium. These results demonstrated the effective coagulation activity of Leonurus artemisia polysaccharides. Thus, the purified LAP-1 could be explored as a promising anticoagulant agent for the treatment of coagulation disorders.

An acidic polysaccharide, denoted LAP-1 was extracted, isolated and purified from Leonurus artemisia (Laur.), in addition to its structure and anticoagulant activity were explored.

Diversity of Sulfated Polysaccharides From Cell Walls of Coenocytic Green Algae and Their Structural Relationships in View of Green Algal Evolution

Seaweeds biosynthesize sulfated polysaccharides as key components of their cell walls. These polysaccharides are potentially interesting as biologically active compounds. Green macroalgae of the class Ulvophyceae comprise sulfated polysaccharides with great structural differences regarding the monosaccharide constituents, linearity of their backbones, and presence of other acidic substituents in their structure, including uronic acid residues and pyruvic acid. These structures have been thoroughly studied in the Ulvales and Ulotrichales, but only more recently have they been investigated with some detail in ulvophytes with giant multinucleate (coenocytic) cells, including the siphonous Bryopsidales and Dasycladales, and the siphonocladous Cladophorales. An early classification of these structurally heterogeneous polysaccharides was based on the presence of uronic acid residues in these molecules. In agreement with this classification based on chemical structures, sulfated polysaccharides of the orders Bryopsidales and Cladophorales fall in the same group, in which this acidic component is absent, or only present in very low quantities. The cell walls of Dasycladales have been less studied, and it remains unclear if they comprise sulfated polysaccharides of both types. Although in the Bryopsidales and Cladophorales the most important sulfated polysaccharides are arabinans and galactans (or arabinogalactans), their major structures are very different. The Bryopsidales produce sulfated pyruvylated 3-linked β-d-galactans, in most cases, with ramifications on C6. For some species, linear sulfated pyranosic β-l-arabinans have been described. In the Cladophorales, also sulfated pyranosic β-l-arabinans have been found, but 4-linked and highly substituted with side chains. These differences are consistent with recent molecular phylogenetic analyses, which indicate that the Bryopsidales and Cladophorales are distantly related. In addition, some of the Bryopsidales also biosynthesize other sulfated polysaccharides, i.e., sulfated mannans and sulfated rhamnans. The presence of sulfate groups as a distinctive characteristic of these biopolymers has been related to their adaptation to the marine environment. However, it has been shown that some freshwater algae from the Cladophorales also produce sulfated polysaccharides. In this review, structures of sulfated polysaccharides from bryopsidalean, dasycladalean, and cladophoralean green algae studied until now are described and analyzed based on current phylogenetic understanding, with the aim of unveiling the important knowledge gaps that still exist.

Structural characterization of ulvan extracted from Ulva clathrata assisted by an ulvan lyase

Rhamnan-rich sulfated polysaccharides extracted from green algae (ulvan) constitute potentially useful natural materials for drug development. However, the characterization of their complex structures poses a challenge for their application. In this study, the structure of ulvan extracted from Ulva clathrata was analyzed with the assistance of an ulvan lyase belonging to the PL25 family. According to mass spectrometry and nuclear magnetic resonance analysis of the degraded oligosaccharides, the backbone of such a polysaccharide mainly consisted of →4)-β-d-GlcA-(1→4)-α-l-Rha3S-(1→ and →4)-β-d-Xyl-(1→4)-α-l-Rha3S-(1→ disaccharide repeating units, and the ratio is approximately 4:1. In addition, about 4% of the xylose moieties bear sulfate groups. Minor amounts of branches containing hexose and unsaturated glucuronic acid were found during the sequence analysis of hexa- to octasaccharides. These results indicated the presence of a long branch in the ulvan. The clarification of the detailed structure provides a foundation for ulvan modification and its structure-activity relationship studies.

Cloning, Expression, and Characterization of a New PL25 Family Ulvan Lyase from Marine Bacterium Alteromonas sp. A321

Ulvan lyases can degrade ulvan to oligosaccharides with potent biological activity. A new ulvan lyase gene, ALT3695, was identified in Alteromonas sp. A321. Soluble expression of ALT3695 was achieved in Escherichia coli BL21 (DE3). The 1314-bp gene encoded a protein with 437 amino acid residues. The amino acid sequence of ALT3695 exhibited low sequence identity with polysaccharide lyase family 25 (PL25) ulvan lyases from Pseudoalteromonas sp. PLSV (64.14% identity), Alteromonas sp. LOR (62.68% identity), and Nonlabens ulvanivorans PLR (57.37% identity). Recombinant ALT3695 was purified and the apparent molecular weight was about 53 kDa, which is different from that of other polysaccharide-degrading enzymes identified in Alteromonas sp. A321. ALT3695 exhibited maximal activity in 50 mM Tris-HCl buffer at pH 8.0 and 50 °C. ALT3695 was relatively thermostable, as 90% activity was observed after incubation at 40 °C for 3 h. The Km and Vmax values of ALT3695 towards ulvan were 0.43 mg·mL-1 and 0.11 μmol·min-1·mL-1, respectively. ESI-MS analysis showed that enzymatic products were mainly disaccharides and tetrasaccharides. This study reports a new PL25 family ulvan lyase, ALT3695, with properties that suggest its great potential for the preparation of ulvan oligosaccharides.

Isolation, structural characterizations and bioactivities of exopolysaccharides produced by Bacillus licheniformis

Extraction polysaccharide from microorganism is a research hotspot. In this work, a new type of water-soluble exopolysaccharides (EPS) was isolated from Bacillus licheniformis. Firstly, response surface methodology (RSM), based on a three-level, three-factor, was used to determine optimum conditions for EPS extraction. And RSM analysis indicated optimum condition was at the temperature of 8 °C for 10.44 h with ethanol at a concentration of 79.22% (v/v), the maximum yield of EPS was 3.07 g/mL. Secondly, EPS were seperated using DEAE-Sepharose Fast Flow column chromatography and acquired two polysaccharide fractions, BL-P1 and BL-P2. BL-P1 had larger molecular weight than BL-P2 from structural analyses, because of higher content of mannose, ribose, glucuronic acid, galactose, arabinose and fructose in BL-P2. Moreover, the characterization of BL-P1 and BL-P2 was investigated with Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy, the results indicated that EPS was mainly composed of→3)-α-d-Galp-(1→, →3,5)-α-l-Araf-(1→, →3)-β-d-Glcp-(1→, β-d-Glcp-(1 → and→4)-β-l-Fucp-(1 → 4)-β-d-Xylp-(1 → 4)-α-l-Rhap (1 → 3) -β-d-Manp-(4 → residues. In vitro antioxidant activity assay, EPS exhibited potent quenching capacities on hydroxyl and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals in a dose-dependent manner. Furthermore, BL-P2 had higher activity than BL-P1 in inhibiting α-amylase and α-glucosidase, which would have potential to be applied in nutraceutical and pharmaceutical industries.

Anticoagulant Activity of Sulfated Ulvan Isolated from the Green Macroalga Ulva rigida

(1) Background: Brown and red algal sulfated polysaccharides have been widely described as anticoagulant agents. However, data on green algae, especially on the Ulva genus, are limited. This study aimed at isolating ulvan from the green macroalga Ulva rigida using an acid- and solvent-free procedure, and investigating the effect of sulfate content on the anticoagulant activity of this polysaccharide. (2) Methods: The obtained ulvan fraction was chemically sulfated, leading to a doubling of the polysaccharide sulfate content in a second ulvan fraction. The potential anticoagulant activity of both ulvan fractions was then assessed using different assays, targeting the intrinsic and/or common (activated partial thromboplastin time), extrinsic (prothrombin time), and common (thrombin time) pathways, and the specific antithrombin-dependent pathway (anti-Xa and anti-IIa), of the coagulation cascade. Furthermore, their anticoagulant properties were compared to those of commercial anticoagulants: heparin and Lovenox®. (3) Results: The anticoagulant activity of the chemically-sulfated ulvan fraction was stronger than that of Lovenox® against both the intrinsic and extrinsic coagulation pathways. (4) Conclusion: The chemically-sulfated ulvan fraction could be a very interesting alternative to heparins, with different targets and a high anticoagulant activity.

Anticoagulant and Antithrombotic Properties in Vitro and in Vivo of a Novel Sulfated Polysaccharide from Marine Green Alga Monostroma nitidum

Sulfated polysaccharides from marine algae have high potential as promising candidates for marine drug development. In this study, a homogeneous sulfated polysaccharide from the marine green alga Monostroma nitidum, designated MS-1, was isolated using water extraction and anion-exchange and size-exclusion chromatography. Results of chemical and spectroscopic analyses showed that MS-1 mainly consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ residues, with additional branches consisting of 4-linked β-d-xylose, 4-/6-linked d-glucose, terminal β-d-glucuronic acid, and 3-/2-linked α-l-rhamnose. Sulfate ester groups substituted mainly at C-2/C-4 of →3)-α-l-Rhap-(1→ and C-4 of →2)-α-l-Rhap-(1→ residues, slightly at C-2 of terminal β-d-glucuronic residues. MS-1 exhibited strong anticoagulant activity in vitro and in vivo as evaluated by the activated partial thromboplastin time and thrombin time assays, and significantly decreased platelet aggregation. The anticoagulant activity mechanism of MS-1 was mainly attributed to strong potentiation thrombin by heparin cofactor-II, and it also hastened thrombin and coagulation factor Xa inhibitions by potentiating antithrombin-III. MS-1 possessed markedly thrombolytic activity evaluated by plasminogen activator inhibitior-1, fibrin degradation products, and D-dimer levels using rats plasma, and recanalization rate by FeCl₃-induced carotid artery thrombosis in mice. MS-1 exhibited strong antithrombotic activity in vitro and in vivo evaluated by the wet weighs and lengths of thrombus, and thrombus occlusion time by electrically-induced carotid artery thrombosis in rats. These results suggested that MS-1 could be a promising marine drug for prevention and therapy of thromboembolic disease.

Antithrombotics from the Sea: Polysaccharides and Beyond

Marine organisms exhibit some advantages as a renewable source of potential drugs, far beyond chemotherapics. Particularly, the number of marine natural products with antithrombotic activity has increased in the last few years, and reports show a wide diversity in scaffolds, beyond the polysaccharide framework. While there are several reviews highlighting the anticoagulant and antithrombotic activities of marine-derived sulfated polysaccharides, reports including other molecules are sparse. Therefore, the present paper provides an update of the recent progress in marine-derived sulfated polysaccharides and quotes other scaffolds that are being considered for investigation due to their antithrombotic effect.