Seaweed-derived Polysaccharides Research Articles

Development of quaternized agar-based materials for the coronavirus inactivation

The COVID-19 pandemic has revealed weaknesses in healthcare systems and underscored the need for advanced antimicrobial materials. This study investigates the quaternization of agar, a seaweed-derived polysaccharide, and the development of electrospun membranes for air filtration in facemasks and biomedical applications. Using the betacoronavirus MHV-3 as a model, quaternized agar and membranes achieved a 90–99.99 % reduction in viral load, without associated cytotoxicity. The quaternization process reduced the viscosity of the solution from 1.19 ± 0.005 to 0.64 ± 0.005 Pa.s and consequently the electrospun fiber diameter ranged from 360 to 185 nm. Membranes synthesized based on polyvinyl alcohol and thermally cross-linked with citric acid exhibited lower water permeability. Avoiding organic solvents in the electrospinning technique ensured eco-friendly production. This approach offers a promising way to develop biocompatible and functional materials for healthcare and environmental applications.

Physiochemical changes, metabolite discrepancies of brown seaweed-derived sulphated polysaccharides in the upper gastrointestinal tract and their effects on bioactive expression

Brown seaweed-derived polysaccharides, notably fucoidan and laminarin, are known for their extensive array of bioactivities and physicochemical properties. However, the effects of upper digestive tract modification on the bioactive performance of fucoidan and laminarin fractions (FLFs) sourced from Australian native species are largely unknown. Here, the digestibility and bioaccessibility of FLFs were evaluated by tracking the dynamic changes in reducing sugar content (CR), profiling the free monosaccharide composition using LC-MS, and comparing high-performance gel permeation chromatography profile variation via LC-SEC-RI. The effects of digestive progression on bioactive performance were assessed by comparing the antioxidant and antidiabetic potential of FLFs and FLF digesta. We observed that molecular weight (Mw) decreased during gastric digestion indicating that FLF aggregates were disrupted in the stomach. During intestinal digestion, Mw gradually decreased and CR increased indicating cleavage of glycosidic bonds releasing free sugars. Although the antioxidant and antidiabetic capacities were not eliminated by the digestion progression, the bioactive performance of FLFs under a digestive environment was reduced contrasting with the same concentration level of the undigested FLFs. These data provide comprehensive information on the digestibility and bioaccessibility of FLFs, and shed light on the effects of digestive progression on bioactive expression.

Wharton's jelly-derived multifunctional hydrogels: New tools to promote intervertebral disc regeneration in vitro and ex vivo.

The degeneration of intervertebral disc (IVD) is a disease of the entire joint between two vertebrae in the spine caused by loss of extracellular matrix (ECM) integrity, to date with no cure. The various regenerative approaches proposed so far have led to very limited successes. An emerging opportunity arises from the use of decellularized ECM as a scaffolding material that, directly or in combination with other materials, has greatly facilitated the advancement of tissue engineering. Here we focused on the decellularized matrix obtained from human umbilical cord Wharton's jelly (DWJ) which retains several structural and bioactive molecules very similar to those of the IVD ECM. However, being a viscous gel, DWJ has limited ability to retain ordered structural features when considered as architecture scaffold. To overcome this limitation, we produced DWJ-based multifunctional hydrogels, in the form of 3D millicylinders containing different percentages of alginate, a seaweed-derived polysaccharide, and gelatin, denatured collagen, which may impart mechanical integrity to the biologically active DWJ. The developed protocol, based on a freezing step, leads to the consolidation of the entire polymeric dispersion mixture, followed by an ionic gelation step and a freeze-drying process. Finally, a porous, stable, easily storable, and suitable matrix for ex vivo experiments was obtained. The properties of the millicylinders (Wharton's jelly millicylinders [WJMs]) were then tested in culture of degenerated IVD cells isolated from disc tissues of patients undergoing surgical discectomy. We found that WJMs with the highest percentage of DWJ were effective in supporting cell migration, restoration of the IVD phenotype (increased expression of Collagen type 2, aggrecan, Sox9 and FOXO3a), anti-inflammatory action, and stem cell activity of resident progenitor/notochordal cells (increased number of CD24 positive cells). We are confident that the DWJ-based formulations proposed here can provide adequate stimuli to the cells present in the degenerated IVD to restart the anabolic machinery.

Sensitivity-based economic analysis of Gracilaria dura cultivation: Comparison of bamboo raft and tube-net techniques along South-east and West Coast of India

The emerging niche applications make agar one of the sought-after seaweed-derived polysaccharides globally. This communication deals with a comprehensive sensitivity-based economic analysis of two farming methods of Gracilaria dura to bring out the best scenario for investors. The profitability assessment parameters under a 50 % increased revenue were favourable. A least payback period of 0.25 years was reported for tube-net method with a high biomass yield; while a breakeven point for the raft and tube-net in single-farmer model were found to be 144 kg and 400 kg respectively; and a net present value of USD 9518 was reported for tube-net based farming. The sensitivity analyses demonstrated that the raft method is not viable, while the tube net farming is economically feasible under scenarios such as 50 % increased revenue of average biomass yield, 25 % and 50 % increased revenues of one crop gain scenario and in all revenue impacts of high biomass yield for G. dura.

Brown Seaweed-Derived Polysaccharides: Comparison of the Extraction Methods by Determining the Physicochemical Properties and Antioxidant Activity

Brown Seaweed-Derived Polysaccharides: Comparison of the Extraction Methods by Determining the Physicochemical Properties and Antioxidant Activity

Durvillaea antarctica: A Seaweed for Enhancing Immune and Cardiometabolic Health and Gut Microbiota Composition Modulation.

Durvillaea antarctica is the seaweed that is the most consumed by the Chilean population. It is recognized worldwide for its high nutritional value in protein, vitamins, minerals, and dietary fiber. This is a narrative review in which an extensive search of the literature was performed to establish the immunomodulator, cardiometabolic, and gut microbiota composition modulation effect of Durvillaea antarctica. Several studies have shown the potential of Durvillaea antarctica to function as prebiotics and to positively modulate the gut microbiota, which is related to anti-obesity, anti-inflammatory, anticancer, lipid-lowering, and hypoglycemic effects. The quantity of Bacteroides was negatively correlated with that of inflammatory monocytes and positively correlated with the levels of several gut metabolites. Seaweed-derived polysaccharides modulate the quantity and diversity of beneficial intestinal microbiota, decreasing phenol and p-cresol, which are related to intestinal diseases and the loss of intestinal function. Additionally, a beneficial metabolic effect related to this seaweed was observed, mainly promoting the decrease in the glycemic levels, lower cholesterol levels and cardiovascular risk. Consuming Durvillaea antarctica has a positive impact on the immune system, and its bioactive compounds provide beneficial effects on glycemic control and other metabolic parameters.

Neoagaro-oligosaccharides Improve the Postharvest Flower Quality and Vase Life of Cut Rose ‘Gaoyuanhong’

Rose is among the most important cut flower crops worldwide. The vase life is an important indicator of cut rose quality. The composition of the vase solution directly affects vase life. Neoagaro-oligosaccharides (NAOS) are degraded seaweed-derived polysaccharides that constitute a group of compounds with small molecular weight and good water solubility. Oligosaccharide treatment can extend the postharvest longevity of certain types of cut flowers; however, little information is available on the utility of NAOS for preservation of cut rose flowers. To explore the effects of NAOS on the longevity and quality of cut flowers of rose ‘Gaoyuanhong’, 100 mg·L−1 NAOS alone and in combination with 10 g·L−1 sucrose were incorporated in the vase solution. Distilled water was used as the control. Physiological indicators, comprising maximum flower diameter, fresh weight, water balance, vase life, bacteria number in the vase solution, and hormone contents of the outer petals, were determined in fresh cut flowers and analyzed. Compared with the control, 100 mg·L−1 NAOS treatment increased the maximum flower diameter (mean 8.21 cm), induced the maximum rates of change in flower diameter and cut flower fresh weight, maintained the best water balance, significantly extended the vase life to 16 days, and reduced the number of bacteria in the vase solution. The abscisic acid content of the outer petals in the control and 100 mg·L−1 NAOS treatments were significantly lower than that of the other treatments on day 9. The results showed that NAOS is useful to improve the postharvest quality and extend the vase life of cut rose flowers, and might contribute to the development of novel alternative preservatives for the cut rose industry.

Structure, rheology, and 3D printing of salt-induced κ-carrageenan gels

κ-carrageenan is a seaweed-derived polysaccharide commonly used in the food and pharmaceutical industry as a thickening agent and rheological modifier. The biopolymer has shown promising potential as a gel-based ink for 3D printing applications. However, its application is limited due to its poor structural stability and mechanical strength. In this work, we propose to overcome the printing limitation by optimizing the ink formulation of salt-induced κ-carrageenan gels. The gelation of 0.25–2% w/v κ-carrageenan with gelling agents of potassium chloride (KCl), calcium chloride (CaCl2), and a combination of KCl and CaCl2 salts was studied using rheological and SANS measurements, and SEM and AFM imaging. A state diagram for the κ-carrageenan-salt samples reveals that the sol-gel transformation shifts to lower κ-carrageenan concentrations with the 25 mM salts. The rheological measurements show a synergistic increase in the storage modulus of κ-carrageenan by the addition of equimolar mixed salts of KCl and CaCl2. The addition of 25 mM KCl or CaCl2 significantly improved the printability of 1% w/v κ-carrageenan to form thin and continuous filaments. However, complex shapes consisting of cylinders, polygons, and multilayer structures could successfully be 3D printed with only the 1% w/v κ-carrageenan with 25 mM KCl gel ink. Live/dead assay of human lung cancer A549 cells seeded on the printed structures show the excellent biocompatibility of these gels.

Seaweed-Derived Polysaccharides Attenuate Heat Stress-Induced Splenic Oxidative Stress and Inflammatory Response via Regulating Nrf2 and NF-κB Signaling Pathways.

With global warming, heat stress (HS) has become a worldwide concern in both humans and animals. The ameliorative effect of seaweed (Enteromorpha prolifera) derived polysaccharides (SDP) on HS-induced oxidative stress and the inflammatory response of an immune organ (spleen) was evaluated using an animal model (Gallus gallus domesticus). In total, 144 animals were used in this 4-week trial and randomly assigned to the following three groups: thermoneutral zone, HS, and HS group supplemented with 1000 mg/kg SDP. Dietary SDP improved the antioxidant capacity and reduced the malondialdehyde (MDA) of the spleen when exposed to HS, regulated via enhancing nuclear factor erythroid 2-related factor-2 (Nrf2) signaling. Furthermore, the inclusion of SDP reduced the levels of pro-inflammatory cytokines and alleviated HS-induced splenic inflammatory response by suppressing the nuclear factor-kappa B (NF-κB) p65 signaling. These findings suggest that the SDP from E. prolifera can be used as a functional food and/or feed supplement to attenuate HS-induced oxidative stress and inflammatory responses of the immune organs. Moreover, the results could contribute to the development of high-value marine products from seaweed for potential use in humans and animals, owing to their antioxidant and anti-inflammatory effects.

Low-Molecular-Weight Seaweed-Derived Polysaccharides Lead to Increased Faecal Bulk but Do Not Alter Human Gut Health Markers.

Seaweeds are potentially sustainable crops and are receiving significant interest because of their rich bioactive compound content; including fatty acids, polyphenols, carotenoids, and complex polysaccharides. However, there is little information on the in vivo effects on gut health of the polysaccharides and their low-molecular-weight derivatives. Herein, we describe the first investigation into the prebiotic potential of low-molecular-weight polysaccharides (LMWPs) derived from alginate and agar in order to validate their in vivo efficacy. We conducted a randomized; placebo-controlled trial testing the impact of alginate and agar LWMPs on faecal weight and other markers of gut health and on composition of gut microbiota. We show that these LMWPs led to significantly increased faecal bulk (20–30%). Analysis of gut microbiome composition by sequencing indicated no significant changes attributable to treatment at the phylum and family level, although FISH analysis showed an increase in Faecalibacterium prausnitzii in subjects consuming agar LMWP. Sequence analysis of gut bacteria corroborated with the FISH data, indicating that alginate and agar LWMPs do not alter human gut microbiome health markers. Crucially, our findings suggest an urgent need for robust and rigorous human in vivo testing—in particular, using refined seaweed extracts.

Decellularized Extracellular Matrix Composite Hydrogel Bioinks for the Development of 3D Bioprinted Head and Neck in Vitro Tumor Models.

Reinforced extracellular matrix (ECM)-based hydrogels recapitulate several mechanical and biochemical features found in the tumor microenvironment (TME) in vivo. While these gels retain several critical structural and bioactive molecules that promote cell-matrix interactivity, their mechanical properties tend toward the viscous regime limiting their ability to retain ordered structural characteristics when considered as architectured scaffolds. To overcome this limitation characteristic of pure ECM hydrogels, we present a composite material containing alginate, a seaweed-derived polysaccharide, and gelatin, denatured collagen, as rheological modifiers which impart mechanical integrity to the biologically active decellularized ECM (dECM). After an optimization process, the reinforced gel proposed is mechanically stable and bioprintable and has a stiffness within the expected physiological values. Our hydrogel's elastic modulus has no significant difference when compared to tumors induced in preclinical xenograft head and neck squamous cell carcinoma (HNSCC) mouse models. The bioprinted cell-laden model is highly reproducible and allows proliferation and reorganization of HNSCC cells while maintaining cell viability above 90% for periods of nearly 3 weeks. Cells encapsulated in our bioink produce spheroids of at least 3000 μm2 of cross-sectional area by day 15 of culture and are positive for cytokeratin in immunofluorescence quantification, a common marker of HNSCC model validation in 2D and 3D models. We use this in vitro model system to evaluate the standard-of-care small molecule therapeutics used to treat HNSCC clinically and report a 4-fold increase in the IC50 of cisplatin and an 80-fold increase for 5-fluorouracil compared to monolayer cultures. Our work suggests that fabricating in vitro models using reinforced dECM provides a physiologically relevant system to evaluate malignant neoplastic phenomena in vitro due to the physical and biological features replicated from the source tissue microenvironment.

Seaweed Components as Potential Modulators of the Gut Microbiota.

Macroalgae, or seaweeds, are a rich source of components which may exert beneficial effects on the mammalian gut microbiota through the enhancement of bacterial diversity and abundance. An imbalance of gut bacteria has been linked to the development of disorders such as inflammatory bowel disease, immunodeficiency, hypertension, type-2-diabetes, obesity, and cancer. This review outlines current knowledge from in vitro and in vivo studies concerning the potential therapeutic application of seaweed-derived polysaccharides, polyphenols and peptides to modulate the gut microbiota through diet. Polysaccharides such as fucoidan, laminarin, alginate, ulvan and porphyran are unique to seaweeds. Several studies have shown their potential to act as prebiotics and to positively modulate the gut microbiota. Prebiotics enhance bacterial populations and often their production of short chain fatty acids, which are the energy source for gastrointestinal epithelial cells, provide protection against pathogens, influence immunomodulation, and induce apoptosis of colon cancer cells. The oral bioaccessibility and bioavailability of seaweed components is also discussed, including the advantages and limitations of static and dynamic in vitro gastrointestinal models versus ex vivo and in vivo methods. Seaweed bioactives show potential for use in prevention and, in some instances, treatment of human disease. However, it is also necessary to confirm these potential, therapeutic effects in large-scale clinical trials. Where possible, we have cited information concerning these trials.

Dietary seaweed-derived polysaccharides improve growth performance of weaned pigs through maintaining intestinal barrier function and modulating gut microbial populations

BackgroundSeaweed-derived polysaccharides (SDP) represent an attractive source of prebiotic nutraceuticals for the food and animal husbandry industry. However, the mechanism by which SDP from Enteromorpha mediates pig growth are not fully understood. This study aimed to investigate how SDP supplementation influences the growth performance and intestinal health in weaned pigs.ResultsIn Exp. 1, 240 weaned pigs were randomly assigned to four dietary treatments and fed with a basal diet or a basal diet containing 200, 400 or 800 mg/kg SDP, respectively, in a 21-day trial. Pigs on the 400 or 800 mg/kg SDP-supplemented group had greater ADG and lower F/G ratio than those on the control group (P<0.05). In Exp. 2, 20 male weaned pigs were randomly assigned to two treatments and fed with a basal diet (CON group) or a basal diet supplemented with 400 mg/kg SDP (the optimum does from Exp. 1), in a 21-day trial. Pigs fed the SDP diet had greater ADG, the concentrations of serum IL-6 and TNF-α and the activities of glutathione peroxidase, superoxide dismutase and catalase (P<0.05), and lower F/G, diarrhea rate, as well as serum D-lactate concentrations and diamine oxidase activity (P<0.05). Moreover, dietary SDP supplementation enhanced secretory immunoglobulin A content, villus height and villous height: crypt depth ratio in small intestine, as well as the lactase and maltase activities in jejunum mucosa (P<0.05). SDP supplementation elevated the mRNA levels of inflammatory response-related genes (IL-6, TNF-α, TLR4, TLR6 and MyD88), and the mRNA and protein levels of ZO-1, claudin-1 and occludin in jejunum mucosa (P<0.05). Importantly, SDP not only increased the Lactobacillus population but also reduced the Escherichia coli population in cecum (P<0.05). Furthermore, SDP increased acetic acid and butyric acid concentrations in cecum (P<0.05).ConclusionsThese results not only suggest a beneficial effect of SDP on growth performance and intestinal barrier functions, but also offer potential mechanisms behind SDP-facilitated intestinal health in weaned pigs.

Synthesis of nickel sulfide-supported on porous carbon from a natural seaweed-derived polysaccharide for high-performance supercapacitors

Transition metal sulfides are regarded as an attractive electrode material because of their excellent metalloid characteristic and good electrical conductivity for supercapacitor applications. Herein, we successfully fabricated a hybrid material of NiSx nanoparticle-supported on porous carbon (NiSx@C) by crosslinking sodium alginate with nickel ions, followed by performing a high-temperature carbonization and low-temperature vulcanization process. The NiS@C and NiS2@C hybrids are obtained through changing the carbonization temperature and adjusting the mass of the S-containing precursor. Both of them are subsequently evaluated for their comparative electrochemical performances. The NiS@C electrode shows an excellent specific capacity of 372.6 mA h g−1 at 0.5 A g−1 with a mass loading of 3.5 mg cm−2, and then retains 216.2 mA h g−1 even if the current density adds up to 10 A g−1. In contrast, the NiS2@C electrode delivers a specific capacity of 213.3 mA h g−1 at 0.5 A g−1 and an impressive capacity retention rate of 60.7% after 5000 charge-discharge cycles. Besides, the asymmetric supercapacitors composed of the NiSx@C hybrids and active carbon (AC) as the positive and negative electrodes deliver excellent energy densities of 58.7 W h kg−1 at a power density of 406.4 W kg−1 (NiS@C//AC device) and 44.4 W h kg−1 at a power density of 397.6 W kg−1 (NiS2@C//AC device), respectively.

Molecular basis of carrageenan-induced cytokines production in macrophages

BackgroundLow molecular weight carrageenan (Cg) is a seaweed-derived sulfated polysaccharide widely used as inflammatory stimulus in preclinical studies. However, the molecular mechanisms of Cg-induced inflammation are not fully elucidated. The present study aimed to investigate the molecular basis involved in Cg-induced macrophages activation and cytokines production.MethodsPrimary culture of mouse peritoneal macrophages were stimulated with Kappa Cg. The supernatant and cell lysate were used for ELISA, western blotting, immunofluorescence. Cg-induced mouse colitis was also developed.ResultsHere we show that Cg activates peritoneal macrophages to produce pro-inflammatory cytokines such as TNF and IL-1β. While Cg-induced TNF production/secretion depends on TLR4/MyD88 signaling, the production of pro-IL-1β relies on TLR4/TRIF/SYK/reactive oxygen species (ROS) signaling pathway. The maturation of pro-IL1β into IL-1β is dependent on canonical NLRP3 inflammasome activation via Pannexin-1/P2X7/K+ efflux signaling. In vivo, Cg-induced colitis was reduced in mice in the absence of NLRP3 inflammasome components.ConclusionsIn conclusion, we unravel a critical role of the NLRP3 inflammasome in Cg-induced pro-inflammatory cytokines production and colitis, which is an important discovery on the pro-inflammatory properties of this sulfated polysaccharide for pre-clinical studies.1e-L4pWBc1sacKrQDF6Cf5Video abstractGraphical Carrageenan (Cg) is one the most used flogistic stimulus in preclinical studies. Nevertheless, the molecular basis of Cg-induced inflammation is not totally elucidated. Herein, Lopes et al. unraveled the molecular basis for Cg-induced macrophages production of biological active IL-1β. The Cg-stimulated macrophages produces pro-IL-1β depends on TLR4/TRIF/Syk/ROS, whereas its processing into mature IL-1β is dependent on the canonical NLRP3 inflammasome.

Sulfated Polysaccharides from Marine Algae as a Basis of Modern Biotechnologies for Creating Wound Dressings: Current Achievements and Future Prospects.

Wound healing involves a complex cascade of cellular, molecular, and biochemical responses and signaling processes. It consists of successive interrelated phases, the duration of which depends on a multitude of factors. Wound treatment is a major healthcare issue that can be resolved by the development of effective and affordable wound dressings based on natural materials and biologically active substances. The proper use of modern wound dressings can significantly accelerate wound healing with minimum scar mark. Sulfated polysaccharides from seaweeds, with their unique structures and biological properties, as well as with a high potential to be used in various wound treatment methods, now undoubtedly play a major role in innovative biotechnologies of modern natural interactive dressings. These natural biopolymers are a novel and promising biologically active source for designing wound dressings based on alginates, fucoidans, carrageenans, and ulvans, which serve as active and effective therapeutic tools. The goal of this review is to summarize available information about the modern wound dressing technologies based on seaweed-derived polysaccharides, including those successfully implemented in commercial products, with a focus on promising and innovative designs. Future perspectives for the use of marine-derived biopolymers necessitate summarizing and analyzing results of numerous experiments and clinical trial data, developing a scientifically substantiated approach to wound treatment, and suggesting relevant practical recommendations.

Marine Seaweed Polysaccharides-Based Engineered Cues for the Modern Biomedical Sector.

Seaweed-derived polysaccharides with unique structural and functional entities have gained special research attention in the current medical sector. Seaweed polysaccharides have been or being used to engineer novel cues with biomedical values to tackle in practice the limitations of counterparts which have become ineffective for 21st-century settings. The inherited features of seaweed polysaccharides, such as those of a biologically tunable, biocompatible, biodegradable, renewable, and non-toxic nature, urge researchers to use them to design therapeutically effective, efficient, controlled delivery, patient-compliant, and age-compliant drug delivery platforms. Based on their significant retention capabilities, tunable active units, swelling, and colloidal features, seaweed polysaccharides have appeared as highly useful materials for modulating drug-delivery and tissue-engineering systems. This paper presents a standard methodological approach to review the literature using inclusion-exclusion criteria, which is mostly ignored in the reported literature. Following that, numerous marine-based seaweed polysaccharides are discussed with suitable examples. For the applied perspectives, part of the review is focused on the biomedical values, i.e., targeted drug delivery, wound-curative potential, anticancer potentialities, tissue-engineering aspects, and ultraviolet (UV) protectant potential of seaweed polysaccharides based engineered cues. Finally, current challenges, gaps, and future perspectives have been included in this review.

Therapeutic effects of an orally administered edible seaweed-derived polysaccharide preparation, ascophyllan HS, on a Streptococcus pneumoniae infection mouse model

Ascophyllan HS is a commercially available preparation of the edible brown alga Ascophyllum nodosum containing ascophyllan, a sulfated polysaccharide with diverse beneficial biological activities. In this study, the effects of ascophyllan HS were evaluated in a severe intranasal Streptococcus pneumoniae infection mouse model. The control untreated mice started to die on day 7 and 80% had died by day 14 post-infection. Continuous oral administration of ascophyllan HS before and after bacterial infection resulted in a remarkable increase in survival rate, with 90% of the low (167 mg/kg body weight/day) and 100% of the high (500 mg/kg body weight/day) dose ascophyllan HS-treated mice surviving at day 14 post-infection. Histopathological observation of the lungs of the infected mice revealed the induction of typical pneumonia features in the alveolar spaces of the untreated control mice, such as extensive infiltration of inflammatory cells, edema, and fibrin deposition. In contrast, notable levels of lung injuries or alterations were not observed in the ascophyllan HS-treated mice, and only a minor lesion was observed in one mouse. Furthermore, bacterial burdens in the lungs were significantly reduced in the ascophyllan HS-treated mice as compared to the control mice at day 4 post-infection. Significantly higher levels of IL-12 were detected in the serum of ascophyllan HS-treated mice than that of control mice measured at the end of the infection experiment (day 14). These results suggest that orally administered ascophyllan HS exerts a therapeutic effect on S. pneumoniae infection by activating the host defense systems. This is the first report of the therapeutic effect of an orally administered seaweed polysaccharide preparation on S. pneumoniae infection. Our findings suggest that ascophyllan HS has the potential to be developed as nutraceuticals and pharmaceuticals applicable for humans as well as a safe and promising therapeutic agent against S. pneumoniae infection.

Ultralow fouling of fibrinogen and human platelets on ulvan multilayer-coated solid surfaces

Enhancement of blood compatibility with the implant surface is critical for biomedical devices. Coating solid surfaces with an anticoagulant is a potentially promising strategy to improve blood compatibility with the implant surface. This study aimed to develop an approach to enhance blood compatibility with titanium/titanium dioxide (Ti/TiO2) surfaces using a green seaweed-derived polysaccharide ulvan. The approach comprises surface coating with tannic acid (TA) and grafting of ulvan onto the surface. Zirconium(IV)-based coordination linkage between ulvan and TA facilitated robust deposition of ulvan multilayers onto Ti/TiO2 surfaces. Adhesion assays revealed that more than 95% of fibrinogen adsorption and platelet adhesion was suppressed through an ulvan multilayer coating. The present results show that ulvan multilayers are robust against chemical and physical treatments and resistant to the adsorption of adherent proteins and human platelets.

Inhibitory effect of polysaccharide of Sargassum weizhouense on PCV2 induced inflammation in mice by suppressing histone acetylation

Seaweeds are excellent source of bioactive compounds and seaweed-derived polysaccharides have demonstrated an array of biological effects. Here, we investigated the effect of polysaccharide of Sargassum weizhouense (PSW) on the inflammatory response in porcine circovirus type 2 (PCV2) infected mice and the underlying mechanism was studied according to the histone acetylation. After PCV2 infection, the levels of TNF-α, IL-1β, IL-6, IL-8, IL-10, MCP-1, COX-1, COX-2 and HAT in both serum and spleen were significantly increased (P <0.05). The mRNA expression of TNF-α, IL-6, IL-10 and NF-κB p65 were elevated in PCV2 infected mice (P <0.05). The HDAC content in both serum and spleen as well the mRNA expression of HDAC1 were greatly decreased (P <0.05). PSW treatment dramatically inhibited the secretions of inflammatory cytokines and HATs, reduced mRNA expression of TNF-α, IL-6, IL-10 and NF-κB p65, but promoted HDAC secretion and mRNA expression of HDAC1 in PCV2-infected mice. The acetylation of both H3 and H4 was significantly up-regulated in PCV2-infected mice, and strongly inhibited by PSW treatment (P <0.01). These results suggested that PCV2 mediate the equilibrium between HATs and HDACs, alternate the histone acetylation and thus DNA packaging, and then activate the transcription of inflammatory cytokines. PSW could inhibit the histone acetylation and the production of inflammatory cytokines, showing excellent potentials in improving the resistance of host against PCV2 infection.