Further data on the structure of brown seaweed fucans: relationships with anticoagulant activity

Marine Bioactive Compounds with Functional Role in Immunity and Food Allergy

Food allergy, referred to as the atypical physiological overreaction of the immune system after exposure to specific food components, is considered one of the major concerns in food safety. The prevalence of this emerging worldwide problem has been increasing during the last decades, especially in industrialized countries, being estimated to affect 6-8% of young children and about 2-4% of adults. Marine organisms are an important source of bioactive substances with the potential to functionally improve the immune system, reduce food allergy sensitization and development, and even have an anti-allergic action in food allergy. The present investigation aims to be a comprehensive report of marine bioactive compounds with verified actions to improve food allergy and identified mechanisms of actions rather than be an exhaustive compilation of all investigations searching beneficial effects of marine compounds in FA. Particularly, this research highlights the capacity of bioactive components extracted from marine microbial, animal, algae, and microalgae sources, such as n-3 long-chain polyunsaturated fatty acids (LC-PUFA), polysaccharide, oligosaccharide, chondroitin, vitamin D, peptides, pigments, and polyphenols, to regulate the immune system, epigenetic regulation, inflammation, and gut dysbiosis that are essential factors in the sensitization and effector phases of food allergy. In conclusion, the marine ecosystem is an excellent source to provide foods with the capacity to improve the hypersensitivity induced against specific food allergens and also bioactive compounds with a potential pharmacological aptitude to be applied as anti-allergenic in food allergy.

Fucoidan refined from Saccharina japonica ameliorates ambient particulate matter-induced inflammation in keratinocytes, underlying fibroblasts, and 12-O-tetradecanoylphorbol 13-acetate-induced ear edema in mice

Fucoidan from Saccharina japonica (SJF) was isolated and characterized, and its anti-inflammatory effects on fine dust/ambient particulate matter (PM)-stimulated HaCaT keratinocytes were investigated. SJF increased cell viability by reducing intracellular ROS production in PM-stimulated HaCaT keratinocytes. Moreover, SJF downregulated the expression/production of inflammatory cytokines (IL-6, IL-8, IL-13, IL-25, IL-33, TNF-α, IFN-γ, and TSLP) and chemokines (MDC and TARC) through modulating NF-κB/MAPK signaling in PM-stimulated HaCaT keratinocytes. Extended studies investigated the impact of SJF-treated HaCaT keratinocyte culture media on HDFs. Interestingly, media from SJF-treated HaCaT keratinocytes on HDFs demonstrated a notable downregulation of the production of inflammatory mediators such as TSLP, IL-6, IL-8, IL-13, and TNF-α, as well as TARC and MDC. Furthermore, the study examined the impact of SJF on 12-O-tetradecanoylphorbol 13-acetate (TPA) induced ear edema in BALB/c mice and results indicated the reduced ear thickness and decreased iNOS and COX-2 expression. Our study confirmed the effectiveness of SJF in ameliorating PM-induced skin inflammation in in vitro experiments, along with the TPA-induced in vivo inflammatory model.

L-fucose and fucoidan alleviate high-salt diet-promoted acute inflammation

Excessive salt intake is a widespread health issue observed in almost every country around the world. A high salt diet (HSD) has a strong correlation with numerous diseases, including hypertension, chronic kidney disease, and autoimmune disorders. However, the mechanisms underlying HSD-promotion of inflammation and exacerbation of these diseases are not fully understood. In this study, we observed that HSD consumption reduced the abundance of the gut microbial metabolite L-fucose, leading to a more substantial inflammatory response in mice. A HSD led to increased peritonitis incidence in mice, as evidenced by the increased accumulation of inflammatory cells and elevated levels of inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and monocyte chemotactic protein-1 (MCP-1, also known as C-C motif chemokine ligand 2 or CCL2), in peritoneal lavage fluid. Following the administration of broad-spectrum antibiotics, HSD-induced inflammation was abolished, indicating that the proinflammatory effects of HSD were not due to the direct effect of sodium, but rather to HSD-induced alterations in the composition of the gut microbiota. By using untargeted metabolomics techniques, we determined that the levels of the gut microbial metabolite L-fucose were reduced by a HSD. Moreover, the administration of L-fucose or fucoidan, a compound derived from brown that is rich in L-fucose, normalized the level of inflammation in mice following HSD induction. In addition, both L-fucose and fucoidan inhibited LPS-induced macrophage activation in vitro. In summary, our research showed that reduced L-fucose levels in the gut contributed to HSD-exacerbated acute inflammation in mice; these results indicate that L-fucose and fucoidan could interfere with HSD-promotion of the inflammatory response.

Fucoidan from brown seaweed Tubinaria decurrens: Structure and structure - anticancer activity relationship

The aims of this study are to determine the structure of a fucoidan from brown seaweed Turbinaria decurrens, to investigate its anticancer activity and structure-activity relationship. SEC-MALLS, IR, ESI-MS and NMR spectra analysis indicated that dominant structure of the fucoidan, with a Mw 122.6 KDa, has a backbone of (1 → 3)- and (1 → 4)-α-L-Fucp residues, branched at C-4, sulfate groups are attached at C-2, C-3 and C-4; branches are (1 → 4)-β-D-Galp residues and sulfated at C-2. The fucoidan was hydrolyzed by HCl aqueous solution to obtain hydrolyzed fucoidans. It is assumed that native and hydrolyzed fucoidans have a rod-like conformation in solution with cross-sectional radius of gyration (Rgc) ranged from 0.53 to 1.52 nm as estimated from SAXS measurements. The fucoidans show great anticancer activity against HT29 human colon cancer cell line with IC50 ranging from 5.41 ± 0.36 to 73.52 ± 2.54 μg/mL. Anticancer activity of the fucoidan could be significantly improved by lowering molecular weight, furthermore, fucoidan required small molecular weight, small molecular weight distribution and rod-like structure with a short branch length for high anticancer activity.

The Discovery of the Fucoidan-Active Endo-1→4-α-L-Fucanase of the GH168 Family, Which Produces Fucoidan Derivatives with Regular Sulfation and Anticoagulant Activity

Sulfated polysaccharides of brown algae, fucoidans, are known for their anticoagulant properties, similar to animal heparin. Their complex and irregular structure is the main bottleneck in standardization and in defining the relationship between their structure and bioactivity. Fucoidan-active enzymes can be effective tools to overcome these problems. In the present work, we identified the gene fwf5 encoding the fucoidan-active endo-fucanase of the GH168 family in the marine bacterium Wenyingzhuangia fucanilytica CZ1127T. The biochemical characteristics of the recombinant fucanase FWf5 were investigated. Fucanase FWf5 was shown to catalyze the endo-type cleavage of the 1→4-O-glycosidic linkages between 2-O-sulfated α-L-fucose residues in fucoidans composed of the alternating 1→3- and 1→4-linked residues of sulfated α-L-fucose. This is the first report on the endo-1→4-α-L-fucanases (EC 3.2.1.212) of the GH168 family. The endo-fucanase FWf5 was used to selectively produce high- and low-molecular-weight fucoidan derivatives containing either regular alternating 2-O- and 2,4-di-O-sulfation or regular 2-O-sulfation. The polymeric 2,4-di-O-sulfated fucoidan derivative was shown to have significantly greater in vitro anticoagulant properties than 2-O-sulfated derivatives. The results have demonstrated a new type specificity among fucanases of the GH168 family and the prospects of using such enzymes to obtain standard fucoidan preparations with regular sulfation and high anticoagulant properties.

Bioactivities of the Popular Edible Brown Seaweed Sargassum fusiforme: A Review

Sargassum fusiforme has a wide range of active constituents (such as polysaccharides, sterols, polyphenols, terpenes, amino acids, trace elements, etc.) and is an economically important brown algae with a long history. In recent years, S. fusiforme has been intensively studied and has attracted wide attention in the fields of agriculture, environment, medicine, and functional food. In this review, we reviewed the current research status of S. fusiforme at home and abroad over the past decade by searching Web of science, Google Scholar, and other databases, and structurally analyzed the active components of S. fusiforme, and on this basis, we focused on summarizing the cutting-edge research and scientific issues on the role of various active substances in S. fusiforme in exerting antioxidant, anti-inflammatory, antitumor, antidiabetic, immunomodulatory, antiviral antibacterial, and anticoagulant effects. The mechanisms by which different substances exert active effects were further summarized by exploring different experimental models and are shown visually. It provides a reference to promote further development and comprehensive utilization of S. fusiforme resources.

Fucoidan from Sargassum autumnale Inhibits Potential Inflammatory Responses via NF-κB and MAPK Pathway Suppression in Lipopolysaccharide-Induced RAW 264.7 Macrophages

Fucoidans are sulfate-rich polysaccharides with a wide variety of beneficial biological activities. The present study aimed to highlight the anti-inflammatory activity of fucoidan from the brown seaweed Sargassum autumnale (SA) against lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. Among the isolated fucoidan fractions, the third fraction (SAF3) showed a superior protective effect on LPS-stimulated RAW 264.7 cells. SAF3 inhibits nitric oxide (NO) production and expression of prostaglandin E-2 (PGE2) via downregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) expression in LPS-induced RAW 26.7 cells. SAF3 treatment decreased pro-inflammatory cytokines IL-1β, TNF-α, and IL-6 expression in LPS-induced cells. LPS stimulation activated NF-κB and MAPK signaling cascades in RAW 264.7 cells, while treatment with SAF3 suppressed them in a concentration-dependent manner. Existing outcomes confirm that SAF3 from S. autumnale possesses potent anti-inflammatory activity and exhibits good potential for application as a functional food ingredient or for the treatment of inflammation-related disorders.

Characterization of an endo-1,3-fucanase from marine bacterium Wenyingzhuangia aestuarii: The first member of a novel glycoside hydrolase family GH174

Sulfated fucans are important marine polysaccharides with various biological and biomedical activities. Fucanases are favorable tools to establish the structure-activity relationships of sulfated fucans. Herein, gene fun174A was discovered from the genome of marine bacterium Wenyingzhuangia aestuarii OF219, and none of the pre-defined glycosidic hydrolase domains were predicted in the protein sequence of Fun174A. Recombinant Fun174A demonstrated a low optimal reaction pH at 5.5. It might degrade sulfated fucans in an endo-processive manner. Glycomics and NMR analyses proved that it specifically hydrolyzed α-1,3-l-fucoside bonds between 2-O-sulfated and non-sulfated fucose residues in the sulfated fucan from sea cucumber Isostichopus badionotus. D119, E120 and E218 were critical for the activity of Fun174A, as identified by site-directed mutagenesis. Three homologs of Fun174A were confirmed to exhibit endo-1,3-fucanase activities. The novelty on sequences of Fun174A and its homologs reveals a new glycoside hydrolase family, GH174.

Purification and Characterization of the Enzyme Fucoidanase from Cobetia amphilecti Utilizing Fucoidan from Undaria pinnatifida

Fucoidanase is an unstable enzyme with high specificity that requires a large about of time to screen it from microorganisms. In this study, enzymatic hydrolysis was used to produce low-molecular-weight fucoidan from microorganisms via the degradation of high-molecular-weight fucoidan without damage to the sulfate esterification structure of oligosaccharide. The microbial strain HN-25 was isolated from sea mud and was made to undergo mutagenicity under ultraviolet light. Fucoidanase was extracted via ultrasonication and its enzymatic activity was improved via optimization of the ultrasonic conditions. The enzymatic properties and degradation efficiency of fucoidanase were characterized. The microbial strain HN-25 is a Gram-negative aerobic and rod-shaped-cell bacterium, and therefore was identified as Cobetia amphilecti via 16s rDNA. The results proved that fucoidanase is a hydrolytic enzyme with a molecular weight of 35 kDa and with high activity and stability at 30 °C and pH 8.0. The activity of fucoidanase was significantly enhanced by sodium and calcium ions and inhibited by a copper ion and ethylenediaminetetraacetate (EDTA). There was a significant decrease in the molecular weight of fucoidan after enzymatic hydrolysis. The low-molecular-weight fuicodan was divided into four fractions, mainly concentrated at F3 (20~10 kDa) and F4 (≤6 kDa). These consequences suggest that fucoidanase obtained from Cobetia amphilecti is stable and efficient and could be a good tool in the production of bioactive compounds.

Immunopotentiating Activity of Fucoidans and Relevance to Cancer Immunotherapy

Fucoidans, discovered in 1913, are fucose-rich sulfated polysaccharides extracted mainly from brown seaweed. These versatile and nontoxic marine-origin heteropolysaccharides have a wide range of favorable biological activities, including antitumor, immunomodulatory, antiviral, antithrombotic, anticoagulant, antithrombotic, antioxidant, and lipid-lowering activities. In the early 1980s, fucoidans were first recognized for their role in supporting the immune response and later, in the 1990s, their effects on immune potentiation began to emerge. In recent years, the understanding of the immunomodulatory effects of fucoidan has expanded significantly. The ability of fucoidan(s) to activate CTL-mediated cytotoxicity against cancer cells, strong antitumor property, and robust safety profile make fucoidans desirable for effective cancer immunotherapy. This review focusses on current progress and understanding of the immunopotentiation activity of various fucoidans, emphasizing their relevance to cancer immunotherapy. Here, we will discuss the action of fucoidans in different immune cells and review how fucoidans can be used as adjuvants in conjunction with immunotherapeutic products to improve cancer treatment and clinical outcome. Some key rationales for the possible combination of fucoidans with immunotherapy will be discussed. An update is provided on human clinical studies and available registered cancer clinical trials using fucoidans while highlighting future prospects and challenges.

A Review on Fucoidan Structure, Extraction Techniques, and Its Role as an Immunomodulatory Agent

Functional ingredients for human health have recently become the focus of research. One such potentially versatile therapeutic component is fucose-containing sulfated polysaccharides (FCSPs), referred to as fucoidans. The exploitation of marine brown algae provides a rich source of FCSPs because of their role as a structural component of the cell wall. Fucoidans are characterized by a sulfated fucose backbone. However, the structural characterization of FCSPs is impeded by their structural diversity, molecular weight, and complexity. The extraction and purification conditions significantly influence the yield and structural alterations. Inflammation is the preliminary response to potentially injurious inducements, and it is of the utmost importance for modulation in the proper direction. Improper manipulation and/or continuous stimuli could have detrimental effects in the long run. The web of immune responses mediated through multiple modulatory/cell signaling components can be addressed through functional ingredients, benefiting patients with no side effects. In this review, we attempted to address the involvement of FCSPs in the stimulation/downregulation of immune response cell signaling. The structural complexity and its foremost influential factor, extraction techniques, have also attracted attention, with concise details on the structural implications of bioactivity.

Structural Characterization and In Vivo Anti-Inflammatory Activity of Fucoidan from Cystoseira crinita (Desf.) Borry

The aim of this study was to evaluate the effects of fucoidan isolated from C. crinita on histamine-induced paw inflammation in rats, and on the serum levels of TNF-α, IL-1β, IL-6, and IL-10 in rats during systemic inflammation response. The levels of TNF-α in a model of acute peritonitis in rats were also investigated. The isolated crude fucoidan was identified as a sulfated xylogalactofucan with high, medium, and low molecular weight fractions and a content of fucose of 39.74%, xylose of 20.75%, and galactose of 15.51%. Fucoidan from C. crinita showed better anti-inflammatory effects in the rat paw edema model, and this effect was present during all stages of the experiment. When compared to controls, a commercial fucoidan from F. vesiculosus, the results also displayed anti-inflammatory activity on the 60th, 90th, and 120th minute of the experiment. A significant decrease in serum levels of IL-1β in rats treated with both doses of C. crinita fucoidan was observed in comparison to controls, whereas TNF-α concentrations were reduced only in the group treated with fucoidan from C. crinita at the dose of 25 mg/kg bw. In the model of carrageenan-induced peritonitis, we observed a tendency of decrease in the levels of the pro-inflammatory cytokine TNF-α in peritoneal fluid after a single dose of C. crinita fucoidan, but this did not reach the statistical significance margin. Single doses of C. crinita fucoidan did not alter serum levels of the anti-inflammatory cytokine IL-10 in animals with lipopolysaccharide-induced systemic inflammation.

Fucoidans of Brown Algae: Comparison of Sulfated Polysaccharides from Fucus vesiculosus and Ascophyllum nodosum

Preparations of sulfated polysaccharides obtained from brown algae are known as fucoidans. These biopolymers have attracted considerable attention due to many biological activities which may find practical applications. Two Atlantic representatives of Phaeophyceae, namely, Fucus vesiculosus and Ascophyllum nodosum, belonging to the same order Fucales, are popular sources of commercial fucoidans, which often regarded as very similar in chemical composition and biological actions. Nevertheless, these two fucoidan preparations are polysaccharide mixtures which differ considerably in amount and chemical nature of components, and hence, this circumstance should be taken into account in the investigation of their biological properties and structure-activity relationships. In spite of these differences, fractions with carefully characterized structures prepared from both fucoidans may have valuable applications in drug development.

Two Ascophyllum nodosum Fucoidans with Different Molecular Weights Inhibit Inflammation via Blocking of TLR/NF-κB Signaling Pathway Discriminately

The present study aimed to clarify the potential mechanism of fucoidans found in Ascophyllum nodosum on anti-inflammation and to further explore the relationship between their structures and anti-inflammation. Two novel fucoidans named ANP-6 and ANP-7 and found in A. nodosum, were separated and purified and their structures were elucidated by HPGPC, HPLC, GC-MS, FT-IR, NMR, and by the Congo red test. They both possessed a backbone constructed of →2)-α-L-Fucp4S-(1→, →3)-α-L-Fucp2S4S-(1→, →6)-β-D-Galp-(1→, and →3,6)-β-D-Galp4S-(1→ with branches of →2)-α-L-Fucp4S-(1→ and →3)-β-D-Galp-(1→. Moreover, ANP-6 and ANP-7 could prevent the inflammation of the LPS-stimulated macrophages by suppressing the NO production and by regulating the expressions of iNOS, COX-2, TNF-α, IL-1β, IL-6, and IL-10. Their inhibitory effects on the TLR-2 and TLR-4 levels suggest that they inhibit the inflammation process via the blocking of the TLR/NF-κB signal transduction. In addition, ANP-6, with a molecular weight (63.2 kDa), exhibited stronger anti-inflammatory capabilities than ANP-7 (124.5 kDa), thereby indicating that the molecular weight has an influence on the anti-inflammatory effects of fucoidans.

Fucoidan-based nanomaterial and its multifunctional role for pharmaceutical and biomedical applications

Fucoidans are promising sulfated polysaccharides isolated from marine sources that have piqued the interest of scientists in recent years due to their widespread use as a bioactive substance. Bioactive coatings and films, unsurprisingly, have seized these substances to create novel, culinary, therapeutic, and diagnostic bioactive nanomaterials. The applications of fucoidan and its composite nanomaterials have a wide variety of food as well as pharmacological properties, including anti-oxidative, anti-inflammatory, anti-cancer, anti-thrombic, anti-coagulant, immunoregulatory, and anti-viral properties. Blends of fucoidan with other biopolymers such as chitosan, alginate, curdlan, starch, etc., have shown promising coating and film-forming capabilities. A blending of biopolymers is a recommended approach to improve their anticipated properties. This review focuses on the fundamental knowledge and current development of fucoidan, fucoidan-based composite material for bioactive coatings and films, and their biological properties. In this article, fucoidan-based edible bioactive coatings and films expressed excellent mechanical strength that can prolong the shelf-life of food products and maintain their biodegradability. Additionally, these coatings and films showed numerous applications in the biomedical field and contribute to the economy. We hope this review can deliver the theoretical basis for the development of fucoidan-based bioactive material and films.

Characterization of a sulfated fucan-specific carbohydrate-binding module: A promising tool for investigating sulfated fucans

Sulfated fucans are important polysaccharides with diverse biological and biomedical activities. Carbohydrate-binding modules (CBMs) could serve as beneficial tools for the investigation of polysaccharides. Nevertheless, no sulfated fucan-binding CBM has been hitherto discovered. In the present study, a novel CBM47 domain was cloned from the marine bacterium Wenyingzhuangia fucanilytica, and heterologously expressed in Escherichia coli. The expressed protein WfCBM47 exhibited a specific binding capacity to sulfated fucans with the backbone composed of 1,3-α-l-fucopyranose residues. Furthermore, a fluorescent probe was successfully constructed by fusing WfCBM47 with a green fluorescent protein, based on which the in situ visualization of sulfated fucan in the sea cucumber (Apostichopus japonicus) body wall was implemented for the first time. The discovery of WfCBM47 provided a promising tool for future investigations on sulfated fucans.

Antiviral Strategies Using Natural Source-Derived Sulfated Polysaccharides in the Light of the COVID-19 Pandemic and Major Human Pathogenic Viruses

Only a mere fraction of the huge variety of human pathogenic viruses can be targeted by the currently available spectrum of antiviral drugs. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak has highlighted the urgent need for molecules that can be deployed quickly to treat novel, developing or re-emerging viral infections. Sulfated polysaccharides are found on the surfaces of both the susceptible host cells and the majority of human viruses, and thus can play an important role during viral infection. Such polysaccharides widely occurring in natural sources, specifically those converted into sulfated varieties, have already proved to possess a high level and sometimes also broad-spectrum antiviral activity. This antiviral potency can be determined through multifold molecular pathways, which in many cases have low profiles of cytotoxicity. Consequently, several new polysaccharide-derived drugs are currently being investigated in clinical settings. We reviewed the present status of research on sulfated polysaccharide-based antiviral agents, their structural characteristics, structure-activity relationships, and the potential of clinical application. Furthermore, the molecular mechanisms of sulfated polysaccharides involved in viral infection or in antiviral activity, respectively, are discussed, together with a focus on the emerging methodology contributing to polysaccharide-based drug development.

Brown Algae Carbohydrates: Structures, Pharmaceutical Properties, and Research Challenges

Brown algae (Phaeophyceae) have been consumed by humans for hundreds of years. Current studies have shown that brown algae are rich sources of bioactive compounds with excellent nutritional value, and are considered functional foods with health benefits. Polysaccharides are the main constituents of brown algae; their diverse structures allow many unique physical and chemical properties that help to moderate a wide range of biological activities, including immunomodulation, antibacterial, antioxidant, prebiotic, antihypertensive, antidiabetic, antitumor, and anticoagulant activities. In this review, we focus on the major polysaccharide components in brown algae: the alginate, laminarin, and fucoidan. We explore how their structure leads to their health benefits, and their application prospects in functional foods and pharmaceuticals. Finally, we summarize the latest developments in applied research on brown algae polysaccharides.

Degraded polysaccharides from Porphyra haitanensis: purification, physico-chemical properties, antioxidant and immunomodulatory activities

To explore effect of the structural properties of porphyra haitanensis polysaccharide on its biological activity, degraded porphyra polysaccharides were separated and purified by Cellulose DEAE-52 and Sephadex G-100 chromatography, obtaining three purified components (P1, P2 and P3). All the three components were sulfate polysaccharides containing the repeating units of → 3) β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →, and → 3) β-D-galactose (1 → 4) α-L-galactose-6-S (1 →, and → 3) 6-O-methyl-β-D-galactose (1 → 4) 3,6-anhydro-α-L-galactose (1 →. The molecular weight of the three fractions was measured to be 300.3, 130.4 and 115.1 kDa, respectively. Their antioxidant activity was investigated by the determination of the free radical scavenging effect and ferric reducing power. It was found that P1, P2 and P3 possessed marked antioxidant activity. It was also found that they appreciably enhanced the proliferation, phagocytic ability and nitric oxide secretion in RAW264.7 cells. Lower molecular weight and higher sulfate content were beneficial to bioactivities of P. haitanensis polysaccharides. Overall, P2 and P3 possess superior immuno-modulatory activity to that of P1 and PHP. Thus, the current work will provide the basis for the better utilization of P. haitanensis to develop the related functional foods.

Fucoidans and Bowel Health

Fucoidans are cell wall polysaccharides found in various species of brown seaweeds. They are fucose-containing sulfated polysaccharides (FCSPs) and comprise 5-20% of the algal dry weight. Fucoidans possess multiple bioactivities, including antioxidant, anticoagulant, antithrombotic, anti-inflammatory, antiviral, anti-lipidemic, anti-metastatic, anti-diabetic and anti-cancer effects. Dietary fucoidans provide small but constant amounts of FCSPs to the intestinal tract, which can reorganize the composition of commensal microbiota altered by FCSPs, and consequently control inflammation symptoms in the intestine. Although the bioactivities of fucoidans have been well described, there is limited evidence to implicate their effect on gut microbiota and bowel health. In this review, we summarize the recent studies that introduce the fundamental characteristics of various kinds of fucoidans and discuss their potential in altering commensal microorganisms and influencing intestinal diseases.

A Review on Molecular Mechanisms and Patents of Marine-derived Anti-thrombotic Agents

Thrombosis is a condition of major concern worldwide as it is associated with life-threatening diseases related to the cardiovascular system. The condition affects 1 in 1000 adults annually, whereas 1 in 4 dies due to thrombosis, and this increases as the age group increases. The major outcomes are considered to be a recurrence, bleeding due to commercially available anti-coagulants, and deaths. The side effects associated with available anti-thrombotic drugs are a point of concern. Therefore, it is necessary to discover and develop an improvised benefit-risk profile drug, therefore, in search of alternative therapy for the treatment of thrombosis, marine sources have been used as promising treatment agents. They have shown the presence of sulfated fucans/galactans, fibrinolytic proteases, diterpenes, glycosaminoglycan, glycoside, peptides, amino acids, sterols, polysaccharides, polyphenols, vitamins, and minerals. Out of these marine sources, many chemicals were found to have anti-thrombotic activities. This review focuses on the recent discovery of anti-thrombotic agents obtained from marine algae, sponges, mussels, and sea cucumber, along with their mechanism of action and patents on its extraction process, preparation methods, and their applications. Further, the article concludes with the author's insight related to marine drugs, which have a promising future.

Are Bioactive Molecules from Seaweeds a Novel and Challenging Option for the Prevention of HPV Infection and Cervical Cancer Therapy?-A Review

Cervical cancer represents one of the leading causes of cancer-related death in women all over the world. The infection with human papilloma virus (HPV) is one of the major risk factors for the development of premalignant lesions, which will progress to cervical cancer. Seaweeds are marine organisms with increased contents of bioactive compounds, which are described as potential anti-HPV and anti-cervical cancer agents. Our study aims to bring together all the results of the previous studies, conducted in order to highlight the potency of bioactive molecules from seaweeds, as anti-HPV and anti-cervical agents. This paper is a review of the English literature published between January 2010 and August 2020. We performed a systematic study in the Google Academic and PubMed databases using the key words "HPV infection", "anticancer", "seaweeds", "cervical cancer" and "carcinogenesis process", aiming to evaluate the effects of different bioactive molecules from marine algae on cervical cancer cell lines and on HPV-infected cells. Only original studies were considered for our research. None of the papers was excluded due to language usage or affiliation. Recent discoveries pointed out that sulfated polysaccharides, such as dextran sulfate heparan or cellulose sulfate, blocked the ability of HPV to infect cells, and inhibited the carcinogenesis process. Carrageenans inhibited the virions of HPV from binding the cellular wall. Fucoidan induced the growth inhibition of HeLa cervical cells in vitro. Heterofucans exhibited antiproliferative effects on cancer cell lines. Terpenoids from brown algae are also promising agents with anti-cervical cancer activity. Considering all the results of the previous studies, we observed that great amounts of bioactive molecules from seaweeds could treat both unapparent HPV infection and clinical visible disease. Furthermore, these molecules were very efficient in the treatment of invasive cervical carcinomas. In these conditions, we consider seaweeds extracts as a novel and challenging therapeutic strategy, and we hope that our study paves the way for further clinical trials in the field.

Exploiting the Amazing Diversity of Natural Source-Derived Polysaccharides: Modern Procedures of Isolation, Engineering, and Optimization of Antiviral Activities

Naturally occurring polysaccharide sulfates are highly diverse, owning variations in the backbone structure, linkage pattern and stereochemistry, branching diversity, sulfate content and positions of sulfate group(s). These structural characteristics bring about diverse sulfated polymers with dissimilar negative charge densities and structure-activity relationships. Herein, we start with a short discussion of techniques needed for extraction, purification, chemical sulfation, and structural characterization of polysaccharides. Processes of isolation and sulfation of plant-derived polysaccharides are challenging and usually involve two steps. In this context, we describe an integrated extraction-sulfation procedure that produces polysaccharide sulfates from natural products in one step, thereby generating additional pharmacological activities. Finally, we provide examples of the spectrum of natural source-derived polysaccharides possessing specific features of bioactivity, in particular focusing on current aspects of antiviral drug development and drug-target interaction. Thus, the review presents a detailed view on chemically engineered polysaccharides, especially sulfated derivatives, and underlines their promising biomedical perspectives.

Structure and Biological Activity Analysis of Fucoidan Isolated from Sargassum siliquosum

Fucoidans are heterologous polysaccharides commonly seen in brown macroalgae and are known for their biological activity including anticancer, antiangiogenic, immunomodulation, and antiviral properties. The brown macroalga Sargassum siliquosum was used for the extraction and analysis of fucoidan in this study. The S. siliquosum fucoidan was indicated as a galactofucoidan composed of sugars, uronate, and sulfate at a ratio of 12:1:4 and its purity was 85% based on the abovementioned three major components. Structural analysis by electrospray ionization collision-induced dissociation tandem mass spectroscopy revealed that the purified fucoidan consisted of a carbohydrate chain composed of (1→3)-linked or (1→4)-linked l-fucose residues, with sulfate groups at C-2 and C-4 positions. Galactose residues with (1→4)-linkages function as the branch points and they are located at the C-3 or C-4 position of fucose residues. Galactose residues are sulfated mainly at C-4 and C-6, while some sulfation can also be seen at C-2. The fucoidan purified from S. siliquosum demonstrated antioxidant, anti-inflammatory, and antilipogenic activities.

Functional Characterization of a New GH107 Endo-α-(1,4)-Fucoidanase from the Marine Bacterium Formosa haliotis

Fucoidans from brown macroalgae are sulfated fucose-rich polysaccharides, that have several beneficial biological activities, including anti-inflammatory and anti-tumor effects. Controlled enzymatic depolymerization of the fucoidan backbone can help produce homogeneous, defined fucoidan products for structure-function research and pharmaceutical uses. However, only a few endo-fucoidanases have been described. This article reports the genome-based discovery, recombinant expression in Escherichia coli, stabilization, and functional characterization of a new bacterial endo-α-(1,4)-fucoidanase, Fhf1, from Formosa haliotis. Fhf1 catalyzes the cleavage of α-(1,4)-glycosidic linkages in fucoidans built of alternating α-(1,3)-/α-(1,4)-linked l-fucopyranosyl sulfated at C2. The native Fhf1 is 1120 amino acids long and belongs to glycoside hydrolase (GH) family 107. Deletion of the signal peptide and a 470 amino acid long C-terminal stretch led to the recombinant expression of a robust, minimized enzyme, Fhf1Δ470 (71 kDa). Fhf1Δ470 has optimal activity at pH 8, 37-40 °C, can tolerate up to 500 mM NaCl, and requires the presence of divalent cations, either Ca2+, Mn2+, Zn2+ or Ni2+, for maximal activity. This new enzyme has the potential to serve the need for controlled enzymatic fucoidan depolymerization to produce bioactive sulfated fucoidan oligomers.

Interactions of fibroblast growth factors with sulfated galactofucan from Saccharina japonica

A total 68 types of marine algae oligosaccharides and polysaccharides were prepared and used to study the structure-activity relationship of oligosaccharides and polysaccharides in their interactions with fibroblast growth factors (FGF) 1 and 2. Factors considered include different types of algae, extraction methods, molecular weight, sulfate content and fractions. In the case of low molecular weight polysaccharide (SJ-D) from Saccharina japonica and its fractions eluting from anion exchange column, both 1.0 M NaCl fraction (SJ-D-I) and 2.0 M NaCl fraction (SJ-D-S) had stronger binding affinity than the parent SJ-D, suggesting that sulfated galactofucans represented the major tight binding component. Nuclear magnetic resonance showed that SJ-D-I was a typical sulfated galactofucan, composed of four units: 1, 3-linked 4-sulfated α-L-fucose (Fuc); 1, 3-linked 2, 4-disulfated α-L-Fuc; 1, 6-linked 4-sulfated β-D-Gal and/or 1, 6-linked 3, 4-sulfated β-D-Gal. Modification by autohydrolysis to oligosaccharides and desulfation decreased the FGF binding affinity while oversulfation increased the affinity. The solution-based affinities of SJ-D-I to FGF1 and FGF2 were 69 nM and 3.9 nM, suggesting that SJ-D-I showed better preferentially binding to FGF1 than a natural ligand, heparin, suggesting that sulfated galactofucan might represent a good regulator of FGF1.

Genome-wide analysis of the Saccharina japonica sulfotransferase genes and their transcriptional profiles during whole developmental periods and under abiotic stresses

BACKGROUND

As a unique sulfated polysaccharide, fucoidan is an important component of cell wall in brown seaweeds. Its biochemical properties are determined by the positions and quantity of sulfate groups. Sulfotransferases (STs) catalyze the sulfation process, which transfer the sulfuryl groups to carbohydrate backbones and are crucial for fucoidan biosynthesis. Nevertheless, the structures and functions of STs in brown seaweeds are rarely investigated.

RESULTS

There are a total of 44 ST genes identified from our genome and transcriptome analysis of Saccharina japonica, which were located in the 17 scaffolds and 11 contigs. The S. japonica ST genes have abundant introns and alternative splicing sites, and five tandem duplicated gene clusters were identified. Generally, the ST genes could be classified into five groups (Group I ~ V) based on phylogenetic analysis. Accordingly, the ST proteins, which were encoded by genes within the same group, contained similar conserved motifs. Members of the S. japonica ST gene family show various expression patterns in different tissues and developmental stages. Transcriptional profiles indicate that the transcriptional levels of more than half of the ST genes are higher in kelp basal blades than in distal blades. Except for ST5 and ST28, most ST genes are down-regulated with the kelp development stages. The expression levels of nine ST genes were detected by real-time quantitative PCR, which demonstrates that they responded to low salinity and drought stresses.

CONCLUSIONS

Various characteristics of the STs allow the feasibilities of S. japonica to synthesize fucoidans with different sulfate groups. This enables the kelp the potential to adapt to the costal environments and meet the needs of S. japonica growth.

Seaweeds as a Functional Ingredient for a Healthy Diet

Seaweeds have been used since ancient times as food, mainly by Asian countries, while in Western countries, their main application has been as gelling agents and colloids for the food, pharmaceuticals, and the cosmetic industry. Seaweeds are a good source of nutrients such as proteins, vitamins, minerals, and dietary fiber. Polyphenols, polysaccharides, and sterols, as well as other bioactive molecules, are mainly responsible for the healthy properties associated with seaweed. Antioxidant, anti-inflammatory, anti-cancer, and anti-diabetic properties are attributed to these compounds. If seaweeds are compared to terrestrial plants, they have a higher proportion of essential fatty acids as eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids. In addition, there are several secondary metabolites that are synthesized by algae such as terpenoids, oxylipins, phlorotannins, volatile hydrocarbons, and products of mixed biogenetic origin. Therefore, algae can be considered as a natural source of great interest, since they contain compounds with numerous biological activities and can be used as a functional ingredient in many technological applications to obtain functional foods.

Enzyme-Assisted Fucoidan Extraction from Brown Macroalgae Fucus distichus subsp. evanescens and Saccharina latissima

Fucoidans from brown macroalgae (brown seaweeds) have different structures and many interesting bioactivities. Fucoidans are classically extracted from brown seaweeds by hot acidic extraction. Here, we report a new targeted enzyme-assisted methodology for fucoidan extraction from brown seaweeds. This enzyme-assisted extraction protocol involves a one-step combined use of a commercial cellulase preparation (Cellic®CTec2) and an alginate lyase from Sphingomonas sp. (SALy), reaction at pH 6.0, 40 °C, removal of non-fucoidan polysaccharides by Ca2+ precipitation, and ethanol-precipitation of crude fucoidan. The workability of this method is demonstrated for fucoidan extraction from Fucus distichus subsp. evanescens (basionym Fucus evanescens) and Saccharina latissima as compared with mild acidic extraction. The crude fucoidans resulting directly from the enzyme-assisted method contained considerable amounts of low molecular weight alginate, but this residual alginate was effectively removed by an additional ion-exchange chromatographic step to yield pure fucoidans (as confirmed by 1H NMR). The fucoidan yields that were obtained by the enzymatic method were comparable to the chemically extracted yields for both F. evanescens and S. latissima, but the molecular sizes of the fucoidans were significantly larger with enzyme-assisted extraction. The molecular weight distribution of the fucoidan fractions was 400 to 800 kDa for F. evanescens and 300 to 800 kDa for S. latissima, whereas the molecular weights of the corresponding chemically extracted fucoidans from these seaweeds were 10-100 kDa and 50-100 kDa, respectively. Enzyme-assisted extraction represents a new gentle strategy for fucoidan extraction and it provides new opportunities for obtaining high yields of native fucoidan structures from brown macroalgae.

Brown Seaweed Fucoidan in Cancer: Implications in Metastasis and Drug Resistance

Fucoidans are sulphated polysaccharides that can be obtained from brown seaweed and marine invertebrates. They have anti-cancer properties, through their targeting of several signaling pathways and molecular mechanisms within malignant cells. This review describes the chemical structure diversity of fucoidans and their similarity with other molecules such as glycosaminoglycan, which enable them to participation in diverse biological processes. Furthermore, this review summarizes their influence on the development of metastasis and drug resistance, which are the main obstacles to cure cancer. Finally, this article discusses how fucoidans have been used in clinical trials to evaluate their potential synergy with other anti-cancer therapies.

Hepatoprotective effect of a fucoidan extract from Sargassum fluitans Borgesen against CCl4-induced toxicity in rats

The in vivo antifibrotic effect of a fucoidan extract (FE) from Sargassum fluitans Borgesen was evaluated in a carbon tetrachloride-induced liver damage model in rats over twelve weeks. Chemical analysis showed the FE to contain carbohydrates, sulfates, uronic acids, protein, phenols, and to have a molecular weight of ~60 kDa. Physiological, biochemical, histological and genetic assays were done. Daily oral administration of FE (50 mg/kg) reduced liver enzymatic activity, liver infiltration of inflammatory cells, collagen fiber deposition and gene expression cytokines such as interleukin beta 1 (IL-β1), tumor necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), Smad-3, Smad-2, collagen 1 alpha 1 (col1α1) and tissue inhibitor of metalloproteinase 1 (TIMP-1). It also increased RNA expression of Smad-7 and metalloproteinase 2 and 9 (MMP2 and MMP9). The fucoidan extract exhibited an antifibrotic effect mediated by the inhibiting TGF-β1/Smad pathway, as well as anti-inflammatory effects.

Fucoidan Inhibition of Osteosarcoma Cells Is Species and Molecular Weight Dependent

Fucoidan is a brown algae-derived polysaccharide having several biomedical applications. This study simultaneously compares the anti-cancer activities of crude fucoidans from Fucus vesiculosus and Sargassum filipendula, and effects of low (LMW, 10-50 kDa), medium (MMW, 50-100 kDa) and high (HMW, >100 kDa) molecular weight fractions of S. filipendula fucoidan against osteosarcoma cells. Glucose, fucose and acid levels were lower and sulphation was higher in F. vesiculosus crude fucoidan compared to S. filipendula crude fucoidan. MMW had the highest levels of sugars, acids and sulphation among molecular weight fractions. There was a dose-dependent drop in focal adhesion formation and proliferation of cells for all fucoidan-types, but F. vesiculosus fucoidan and HMW had the strongest effects. G1-phase arrest was induced by F. vesiculosus fucoidan, MMW and HMW, however F. vesiculosus fucoidan treatment also caused accumulation in the sub-G1-phase. Mitochondrial damage occurred for all fucoidan-types, however F. vesiculosus fucoidan led to mitochondrial fragmentation. Annexin V/PI, TUNEL and cytochrome c staining confirmed stress-induced apoptosis-like cell death for F. vesiculosus fucoidan and features of stress-induced necrosis-like cell death for S. filipendula fucoidans. There was also variation in penetrability of different fucoidans inside the cell. These differences in anti-cancer activity of fucoidans are applicable for osteosarcoma treatment.

Pharmaceutical Development and Safety Evaluation of a GMP-Grade Fucoidan for Molecular Diagnosis of Cardiovascular Diseases

The adhesion molecule P-selectin is present on the cell surface of both activated endothelium and activated platelets. The present study describes the pharmaceutical development, safety evaluation, and preclinical efficacy of a micro-dosed radiotracer. The macromolecular nanoscale assembly consisted of a natural compound made of a sulfated fucose-rich polysaccharides (fucoidan) and a radionuclide (technetium-99m) for the detection of P-selectin expression in cardiovascular diseases. After extraction and fractionation from brown seaweeds, the good manufacturing practice (GMP) production of a low molecular weight (LMW) fucoidan of 7 kDa was achieved and full physicochemical characterization was performed. The regulatory toxicology study in rats of the GMP batch of LMW fucoidan revealed no adverse effects up to 400 μg/kg (×500 higher than the expected human dose) and pseudoallergy was not seen as well. In a myocardial ischemia-reperfusion model in rats, the GMP-grade LMW fucoidan labeled with technetium-99m detected P-selectin upregulation in vivo. The present study supports the potential of using ^99mTc-fucoidan as an imaging agent to detect activated endothelium in humans.

Carbocatalysed hydrolytic cleaving of the glycosidic bond in fucoidan under microwave irradiation

Biomass valorization involves breaking down naturally occurring long chain polysaccharides into their constituent monomers. The polysaccharide chain consists of monomers adjoined via C (carbon)-O (oxygen) glycosidic linkages that are typically cleaved via hydrolytic scission. In this study, we aimed to recover fucose from the polysaccharide fucoidan, which can be extracted from seaweed biomass. We investigated the depolymerisation behavior of fucoidan sourced from two different species of seaweeds, namely Undaria pinnatifida (F-UP) and Fucus vesiculosus (F-FV). Catalytic depolymerisation experiments were performed using four different carbon-based catalysts - graphene, multiwalled carbon nanotubes (MWCNT), graphene oxide (GO), and reduced graphene oxide (rGO) - under microwave (MW) irradiation. Our results showed that the depolymerisation of fucoidan was best achieved using GO, which was attributed to the abundance of oxygen functionalities on its surface. Furthermore, based on gel permeation chromatography analyses, the depolymerisation of fucoidan was found to follow a two-step process: (1) random scission leading to the production of short-chain oligosaccharides and (2) acid-catalysed hydrolysis of the oligosaccharides to fucose. Because of the longer chain length of F-UP (61 kDa), the highest fucose yield of 17.4% using this species was obtained at a higher temperature of 120 °C in a closed vessel. Meanwhile, in the case of F-FV (1.1 kDa), the highest yield of 54.0% was obtained under reflux conditions at a lower temperature of 104 °C. Our mechanistic study based on semi-empirical quantum calculations also revealed that the recovery of fucose from F-FV is more energetically favoured than from F-UP as a result of their structural differences.

In situ synthesis of core-shell carbon nanowires as a potent targeted anticoagulant

We have developed a one-pot synthesis of bio-carbon nanowires from the natural product sodium alginate at low temperature, without using any catalyst, for anticoagulation applications. Sodium alginate is carbonized and sulfated/sulfonated in situ by solid state heating of a mixture of sodium alginate and ammonium sulfite. By regulating the heating temperature and the ratio of ammonium sulfite to sodium alginate, we modulated the degree of sulfation/sulfonation and carbonization, as well as the morphology of the carbon nanomaterials. The core-shell sulfated/sulfonated bio-carbon nanowires (CNWs_Alg@SOx) made by the reaction of a mixture of ammonium sulfite and sodium alginate with a mass ratio of 5 (ammonium sulfite to sodium alginate) at 165 °C for 3 h, exhibit strong inhibition of thrombin activity due to their ultrahigh binding affinity towards it (dissociation constant (K_d) = 8.7 × 10^-11 M). The possible formation mechanism of the carbon nanowires has been proposed. The thrombin-clotting time delay caused by CNWs_Alg@SOx is ∼ 170 times longer than that caused by sodium alginate. Hemolysis and cytotoxicity assays demonstrated the high biocompatibility of CNWs_Alg@SOx. Furthermore, the thromboelastography of whole-blood coagulation and rat-tail bleeding assays further reveal that CNWs_Alg@SOx have a much stronger anticoagulation activity than sodium alginate and naturally sulfated polysaccharides (e.g., fucoidan). Our results suggest that the low-temperature prepared, cost-effective, and highly biocompatible CNWs_Alg@SOx show great potential as an efficient anticoagulant for the prevention and treatment of diseases associated with thrombosis.

Fucoidan Suppresses Mitochondrial Dysfunction and Cell Death against 1-Methyl-4-Phenylpyridinum-Induced Neuronal Cytotoxicity via Regulation of PGC-1α Expression

Mitochondria are considered to be the powerhouses of cells. They are the most commonly damaged organelles within dopaminergic neurons in patients with Parkinson's disease (PD). Despite the importance of protecting neuronal mitochondria in PD patients, the detailed mechanisms underlying mitochondrial dysfunction during pathogenesis and pathophysiological progression of PD have not yet been elucidated. We investigated the protective action of fucoidan against the detrimental action of 1-methyl-4-phenyl-pyridinium (MPP⁺), a neurotoxin used to model PD, in the mitochondria of SH-SY5Y neural cells. Fucoidan increased the expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and protected the cells from MPP⁺-induced apoptosis by upregulating the 5' adenosine monophosphate-activated protein kinase (AMPK)-PGC-1α axis. These effects were blocked by the silencing of the PGC-1α axis. These results indicated that fucoidan protects SH-SY5Y cells from mitochondrial dysfunction and cell death caused by MPP⁺ treatment, via the AMPK-PGC-1α axis. These findings also suggest that fucoidan could potentially be used as a therapeutic agent for PD.

Therapeutic Effects of Fucoidan: A Review on Recent Studies

Fucoidan is a polysaccharide largely made up of l-fucose and sulfate groups. Fucoidan is favorable worldwide, especially amongst the food and pharmaceutical industry as a consequence of its promising therapeutic effects. Its applaudable biological functions are ascribed to its unique biological structure. Classical bioactivities associated with fucoidan include anti-oxidant, anti-tumor, anti-coagulant, anti-thrombotic, immunoregulatory, anti-viral and anti-inflammatory effects. More recently, a variety of in vitro and in vivo studies have been carried out to further highlight its therapeutic potentials. This review focuses on the progress towards understanding fucoidan and its biological activities, which may be beneficial as a future therapy. Hence, we have summarized in vitro and in vivo studies that were done within the current decade. We expect this review and a variety of others can contribute as a theoretical basis for understanding and inspire further product development of fucoidan.

Fucoidans from the phaeophyta Scytosiphon lomentaria: Chemical analysis and antiviral activity of the galactofucan component

The brown seaweed Scytosiphon lomentaria produces moderate amounts of fucoidans. By cetrimide fractionation, typical heavily sulfated galactofucans are obtained, with no major signs of chemical heterogeneity, together with fractions with higher proportions of xylose, mannose and uronic acids. Anyway, fucose is the most important monosaccharide in most of the subfractions of the subsequent extracts. The fucan moieties appear to be mostly as 3-linked α-l-fucopyranosyl units, with several patterns of sulfate and branching. Galactose is mostly 6-linked, whereas mannose appears to be 2-linked, and xylose appears mostly as terminal stubs. Small amounts of 2-O-acetylated fucose units appear. A high and selective antiviral activity against HSV-1 and HSV-2 was determined for the galactofucan fractions whereas the uronofucoidans were inactive.

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.

A marine-sourced fucoidan solution inhibits Toll-like-receptor-3-induced cytokine release by human bronchial epithelial cells

Fucoidans are sulfated polysaccharides from brown algae, known to have immunomodulatory activity. Their effects on the response of airway epithelial cells to Toll-like receptor 3 (TLR3) stimulation have not been characterized. Our objective was to evaluate the effects of a marine-sourced fucoidan solution (MFS) on the TLR3-induced expression and/or production of cytokines and prostaglandin by human primary bronchial epithelial cells as a model of the airway epithelium. The cells were incubated with MFS in the presence or absence of Poly(I:C) (a TLR3 agonist that mimics viral RNA). Cytokine expression and production were assessed using RT-qPCR and ELISA. The expression of cyclooxygenase-2 and the production of prostaglandin E2 were also measured. Relative to control, exposure to MFS was associated with lower Poly(I:C)-induced mRNA expression of various cytokines and chemokines, and lower COX-2 production. The MFS inhibited the production of some cytokines (IL-1α, IL-1β, TNFα, and IL-6), chemokines (CCL5, CCL22, CXCL1, CXCL5 and CXCL8) and prostaglandin E2 but did not alter the production of IL-12/25, CCL2 and CCL20. At clinically relevant concentrations, the MFS inhibited the TLR3-mediated production of inflammatory mediators by human primary bronchial epithelial cells - suggesting that locally applied MFS might help to reduce airway inflammation in viral infections.

Fucoidan Structure and Activity in Relation to Anti-Cancer Mechanisms

Fucoidan is a natural derived compound found in different species of brown algae and in some animals, that has gained attention for its anticancer properties. However, the exact mechanism of action is currently unknown. Therefore, this review will address fucoidans structure, the bioavailability, and all known different pathways affected by fucoidan, in order to formulate fucoidans structure and activity in relation to its anti-cancer mechanisms. The general bioactivity of fucoidan is difficult to establish due to factors like species-related structural diversity, growth conditions, and the extraction method. The main pathways influenced by fucoidan are the PI3K/AKT, the MAPK pathway, and the caspase pathway. PTEN seems to be important in the fucoidan-mediated effect on the AKT pathway. Furthermore, the interaction with VEGF, BMP, TGF-β, and estrogen receptors are discussed. Also, fucoidan as an adjunct seems to have beneficial effects, for both the enhanced effectiveness of chemotherapy and reduced toxicity in healthy cells. In conclusion, the multipotent character of fucoidan is promising in future anti-cancer treatment. However, there is a need for more specified studies of the structure⁻activity relationship of fucoidan from the most promising seaweed species.

Macroalgal Polysaccharides in Biomimetic Nanodelivery Systems

BACKGROUND

Imitating nature in the design of bio-inspired drug delivery systems resulted in several success stories. However, the practical application of biomimicry is still largely unrealized owing to the fact that we tend to copy the shape more often than the whole biology. Interesting chemistry of polysaccharides provides endless possibilities for drug complex formation and creation of delivery systems with diverse morphological and surface properties. However, the type of biological response, which may be induced by these systems, remains largely unexploited.

METHODS

Considering the most current research for the given topic, in this review, we will try to present the integrative approaches for the design of biomimetic DDS's with improved therapeutic or theranostic effects based on different algal polysaccharides that exert multiple biological functions.

RESULTS

Algal polysaccharides may provide building blocks for bioinspired drug delivery systems capable of supporting the mechanical properties of nanomedicines and mimicking various biological processes by molecular interactions at the nanoscale. Numerous research studies demonstrate the efficacy and safety of multifunctional nanoparticles integrating several functions in one delivery system, composed of alginate, carrageenan, ulvan, fucoidan and their derivatives, intended to be used as bioartificial microenvironment or for diagnosis and therapy of different diseases.

CONCLUSION

Nanodimensional structure of polysaccharide DDS's shows substantial influence on the bioactive motifs potential availability for interaction with a variety of biomolecules and cells. Evaluation of the nano dimensional structure-activity relationship is crucial for unlocking the full potential of the future application of polysaccharide bio-mimicking DDS in modern diagnostic and therapeutic procedures.

Discovery and screening of novel metagenome-derived GH107 enzymes targeting sulfated fucans from brown algae

Sulfated fucans, often denoted as fucoidans, are highly variable cell wall polysaccharides of brown algae, which possess a wide range of bioactive properties with potential pharmaceutical applications. Due to their complex architecture, the structures of algal fucans have until now only been partly determined. Enzymes capable of hydrolyzing sulfated fucans may allow specific release of defined bioactive oligosaccharides and may serve as a tool for structural elucidation of algal walls. Currently, such enzymes include only a few hydrolases belonging to the glycoside hydrolase family 107 (GH107), and little is known about their mechanistics and the substrates they degrade. In this study, we report the identification and recombinant production of three novel GH107 family proteins derived from a marine metagenome. Activity screening against a large substrate collection showed that all three enzymes degraded sulfated fucans from brown algae in the order Fucales. This is in accordance with a hydrolytic activity against α-1,4-fucosidic linkages in sulfated fucans as reported for previous GH107 members. Also, the activity screening gave new indications about the structural differences in brown algal cell walls. Finally, sequence analyses allowed identification of the proposed catalytic residues of the GH107 family. The findings presented here form a new basis for understanding the GH107 family of enzymes and investigating the complex sulfated fucans from brown algae. DATABASE: The assembled metagenome and raw sequence data is available at EMBL-EBI (Study number: PRJEB28480). Sequences of the GH107 fucanases (Fp273, Fp277, and Fp279) have been deposited in GenBank under accessions MH755451-MH755453.