Fucoidans and fucoidanases--focus on techniques for molecular structure elucidation and modification of marine polysaccharides

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.

The physiological activities of fucoidan and its application in animal breeding

Fucoidan, a water-soluble heteropolysaccharide predominantly found in brown algae, comprises active components such as fucose and sulfate groups. This polysaccharide exhibits a range of physiological activities, including antioxidant, antiviral, anticancer, and immunomodulatory activities. In light of the global prohibition of antibiotics in animal feed, there is increasing interest in identifying safe, natural antibiotic alternatives that lack toxic side effects. This study focuses on analysing the impact of fucoidan in animal husbandry and provides a comprehensive review of the methods for preparing fucoidan, along with its physical and chemical characteristics. Its applications in the breeding of aquatic species, livestock, and poultry have also been summarized. The aim of this study was to establish a theoretical framework for the use of fucoidan in animal husbandry and to contribute to the theoretical underpinnings of the animal breeding and feed industries.

Understanding Macroalgae: A Comprehensive Exploration of Nutraceutical, Pharmaceutical, and Omics Dimensions

Driven by a surge in global interest in natural products, macroalgae or seaweed, has emerged as a prime source for nutraceuticals and pharmaceutical applications. Characterized by remarkable genetic diversity and a crucial role in marine ecosystems, these organisms offer not only substantial nutritional value in proteins, fibers, vitamins, and minerals, but also a diverse array of bioactive molecules with promising pharmaceutical properties. Furthermore, macroalgae produce approximately 80% of the oxygen in the atmosphere, highlighting their ecological significance. The unique combination of nutritional and bioactive attributes positions macroalgae as an ideal resource for food and medicine in various regions worldwide. This comprehensive review consolidates the latest advancements in the field, elucidating the potential applications of macroalgae in developing nutraceuticals and therapeutics. The review emphasizes the pivotal role of omics approaches in deepening our understanding of macroalgae's physiological and molecular characteristics. By highlighting the importance of omics, this review also advocates for continued exploration and utilization of these extraordinary marine organisms in diverse domains, including drug discovery, functional foods, and other industrial applications. The multifaceted potential of macroalgae warrants further research and development to unlock their full benefits and contribute to advancing global health and sustainable industries.

Chemical Composition, Antioxidant, and Antitumor Activity of Fucoidan from the Brown Alga Dictyota dichotoma

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05-1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity.

Fucoidan, a brown seaweed polysaccharide in nanodrug delivery

Fucoidan-a sulfated marine seaweed obtained from brown algae-has raised considerable interest in the scientific community over the last decade as it possesses a wide range of biological activities such as antioxidant, antiviral, anti-inflammatory, anticoagulant, antithrombotic, anticarcinogenic, and immunoregulatory. This polysaccharide finds application as a drug delivery vehicle due to its non-cytotoxicity, biocompatibility, and biodegradability. Besides, nano biomedical systems have used this marine alga for diagnostic and therapeutic purposes. Fucoidan has been extensively studied for use in regenerative medicines, in wound healing, and for sustained drug delivery due to its large biodiversity, cost-effectiveness, and mild procedures for extraction and purification. However, the main concern that limits its application is the variance in its batch-to-batch extraction owing to species type, harvesting, and climatic factors. The current review encloses a compendious overview of the origin, chemical structure, and physicochemical and biological properties of fucoidan and its significant role in nanodrug delivery systems. Special emphasis is given to the recent advances in the use of native/modified fucoidan, its combination with chitosan and metal ions for nanodrug delivery applications, especially in cancer treatment. Additionally, use of fucoidan in human clinical trials as a complementary therapeutic agent is also reviewed.

In vitro anticancer potential of laminarin and fucoidan from Brown seaweeds

Marine seaweeds are rich source of polysaccharides present in their cell wall and are cultivated and consumed in China, Japan, Korea, and South Asian countries. Brown seaweeds (Phaeophyta) are rich source of polysaccharides such as Laminarin and Fucoidan. In present study, both the laminarin and fucoidan were isolated was yielded higher in PP (Padina pavonica) (4.36%) and STM (Stoechospermum marginatum) (2.32%), respectively. The carbohydrate content in laminarin and fucoidan was 86.91% and 87.36%, whereas the sulphate content in fucoidan was 20.68%. Glucose and mannose were the major monosaccharide units in laminarin (PP), however, fucose, galactose, and xylose in fucoidan (STM). FT-IR down peaks represent the carbohydrate of laminarin and fucoidan except, for 1219 cm-1, and 843 cm-1, illustrating the sulphate groups of fucoidan. The molecular weight of laminarin was 3-5 kDa, and the same for fucoidan was 2-6 kDa, respectively. Both the Fucoidan and Laminarin showed null cytotoxicity on Vero cells. Contrastingly, the fucoidan possess cytotoxic activity on human liver cancer cells (HepG2) (IC50-24.4 ± 1.5 µg/mL). Simultaneously, laminarin also shown cytotoxicity on human colon cancer cells (HT-29) (IC50-57 ± 1.2 µg/mL). The AO/EB (Acriding Orange/Ethidium Bromide) assay significantly resulted in apoptosis and necrosis upon laminarin and fucoidan treatments, respectively. The DNA fragmentation results support necrotic cancer cell death. Therefore, laminarin and fucoidan from PP and STM were potential bioactive compounds for anticancer therapy.

Development of a Novel Marine-Derived Tricomposite Biomaterial for Bone Regeneration

Bone tissue engineering is a promising treatment for bone loss that requires a combination of porous scaffold and osteogenic cells. The aim of this study was to evaluate and develop a tricomposite, biomimetic scaffold consisting of marine-derived biomaterials, namely, chitosan and fucoidan with hydroxyapatite (HA). The effects of chitosan, fucoidan and HA individually and in combination on the proliferation and differentiation of human mesenchymal stem cells (MSCs) were investigated. According to the SEM results, the tricomposite scaffold had a uniform porous structure, which is a key requirement for cell migration, proliferation and vascularisation. The presence of HA and fucoidan in the chitosan tricomposite scaffold was confirmed using FTIR, which showed a slight decrease in porosity and an increase in the density of the tricomposite scaffold compared to other formulations. Fucoidan was found to inhibit cell proliferation at higher concentrations and at earlier time points when applied as a single treatment, but this effect was lost at later time points. Similar results were observed with HA alone. However, both HA and fucoidan increased MSC mineralisation as measured by calcium deposition. Differentiation was significantly enhanced in MSCs cultured on the tricomposite, with increased alkaline phosphatase activity on days 17 and 25. In conclusion, the tricomposite is biocompatible, promotes osteogenesis, and has the structural and compositional properties required of a scaffold for bone tissue engineering. This biomaterial could provide an effective treatment for small bone defects as an alternative to autografts or be the basis for cell attachment and differentiation in ex vivo bone tissue engineering.

Novel Fucoidan Pharmaceutical Formulations and Their Potential Application in Oncology-A Review

Fucoidan belongs to the family of marine sulfated, L-fucose-rich polysaccharides found in the cell wall matrix of various brown algae species. In the last few years, sulfated polysaccharides have attracted the attention of researchers due to their broad biological activities such as anticoagulant, antithrombotic, antidiabetic, immunomodulatory, anticancer and antiproliferative effects. Recently the application of fucoidan in the field of pharmaceutical technology has been widely investigated. Due to its low toxicity, biocompatibility and biodegradability, fucoidan plays an important role as a drug carrier for the formulation of various drug delivery systems, especially as a biopolymer with anticancer activity, used for targeted delivery of chemotherapeutics in oncology. Furthermore, the presence of sulfate residues with negative charge in its structure enables fucoidan to form ionic complexes with oppositely charged molecules, providing relatively easy structure-forming properties in combination with other polymers. The aim of the present study was to overview essential fucoidan characteristics, related to its application in the development of pharmaceutical formulations as a single drug carrier or in combinations with other polymers. Special focus was placed on micro- and nanosized drug delivery systems with polysaccharides and their application in the field of oncology.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

The anti-inflammatory action of fucoidans is well known, based on both in vitro and some in vivo studies. The other biological properties of these compounds, their lack of toxicity, and the possibility of obtaining them from a widely distributed and renewable source, makes them attractive novel bioactives. However, fucoidans’ heterogeneity and variability in composition, structure, and properties depending on seaweed species, biotic and abiotic factors and processing conditions, especially during extraction and purification stages, make it difficult for standardization. A review of the available technologies, including those based on intensification strategies, and their influence on fucoidan composition, structure, and anti-inflammatory potential of crude extracts and fractions is presented.

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.

Health benefits and potential applications of fucoidan (FCD) extracted from brown seaweeds in aquaculture: An updated review

Nowadays, the application of immunomodulators in aquaculture has become of an urgent need because of high incidence of fish and shrimp diseases. For a long time, researchers have paid great interest to find suitable, relatively economical, and environmentally safe immunostimulant products to be used either as feed or water additives to boost immunity and increase the resistance of fish and shrimp against the challenging pathogens. Probiotics, prebiotics, synbiotics, phytobiotics, herbal extracts, microalgae, macroalgae, and essential oils have been extensively evaluated. Brown seaweeds (Phaeophyceae) are a large group of multi-cellular macroalgae that are widely distributed in marine aquatic environments. They are abundant in several bioactive sulfated polysaccharides known as fucoidan (FCD). Research studies demonstrated the beneficial functions of FCD in human medicine because of its immunomodulating, antioxidant, anti-allergic, antitumor, antiviral, anti-inflammatory, and hepatoprotective effects. In aquaculture, several researchers have tested the benefits and potential applications of FCD in aquafeed. This literature review provides an updated information and key references of research studies that focused principally on using FCD in aquaculture. Its effects on growth, intestinal health, antioxidant capacity, and immune responses of several finfish and shellfish species will be discussed. This review paper will also highlight the potential efficacy and mechanisms of FCD in the modulation of toxicity signs and increasing the resistance of fish and shrimp against bacterial and viral infections. Hence, this contribution will be valuable to maintain aquaculture sustainability and to improve the health and welfare of farmed fish and shrimp.

Real-time changes of the adsorption process and conformation of marine dissolved organic matters on the solid-liquid interface

In this study, the adsorption characteristics of marine dissolved organic matters (MDOMs) on the solid-liquid interface in the coastal waters was investigated. The results showed that the organic macromolecules with adsorption ability in MDOMs are not rigid molecules. However, the macromolecules have viscoelasticity properties. At different dilution ratios, the MDOMs adsorption process includes rapid (0-200 s) and slow adsorption (200 s later) periods. MDOMs adsorption in the solid-liquid interface is a dynamic process in which adsorption and hydration occur simultaneously. MDOMs concentration is an important driving force for adsorption. The three macromolecules of acid polysaccharides, protein-like, and polycarboxylate-type humic acids in MDOMs are rich in functional groups and they have the ability to absorb to solid surface. Acidic polysaccharides exhibit a sustained adsorption ability, while the adsorption of other macromolecules occurred only in the initial rapid adsorption period. In addition, the acid polysaccharides show weak thixotropy during the adsorption process. It would cause the stretching of macromolecular structure of the adsorption layer, enhancing the hydration of the adsorption layer. The study shows the adsorption process of MDOMs at the solid-liquid interface and the structural characteristics of the adsorption layer. It can provide helpful information for the inhibition and removal of MDOMs pollution during the actual development of marine resources.

Purification and Characterization of a Novel Alginate Lyase from a Marine Streptomyces Species Isolated from Seaweed

Alginate, a natural polysaccharide derived from brown seaweed, is finding multiple applications in biomedicine via its transformation through chemical, physical, and, increasingly, enzymatic processes. In this study a novel alginate lyase, AlyDS44, was purified and characterized from a marine actinobacterium, Streptomyces luridiscabiei, which was isolated from decomposing seaweed. The purified enzyme had a specific activity of 108.6 U/mg, with a molecular weight of 28.6 kDa, and was composed of 260 amino acid residues. AlyDS44 is a bifunctional alginate lyase, active on both polyguluronate and polymannuronate, though it preferentially degrades polyguluronate. The optimal pH of this enzyme is 8.5 and the optimal temperature is 45 °C. It is a salt-tolerant alginate lyase with an optimal activity at 0.6 M NaCl. Metal ions Mn²⁺, Co²⁺, and Fe²⁺ increased the alginate degrading activity, but it was inhibited in the presence of Zn²⁺ and Cu²⁺. The highly conserved regions of its amino acid sequences indicated that AlyDS44 belongs to the polysaccharide lyase family 7. The main breakdown products of the enzyme on alginate were disaccharides, trisaccharides, and tetrasaccharides, which demonstrated that this enzyme acted as an endo-type alginate lyase. AlyDS44 is a novel enzyme, with the potential for efficient production of alginate oligosaccharides with low degrees of polymerization.

Seaweed-Based Molecules and Their Potential Biological Activities: An Eco-Sustainable Cosmetics

Amongst the countless marine organisms, seaweeds are considered as one of the richest sources of biologically active ingredients having powerful biological activities. Seaweeds or marine macroalgae are macroscopic multicellular eukaryotic photosynthetic organisms and have the potential to produce a large number of valuable compounds, such as proteins, carbohydrates, fatty acids, amino acids, phenolic compounds, pigments, etc. Since it is a prominent source of bioactive constituents, it finds diversified industrial applications viz food and dairy, pharmaceuticals, medicinal, cosmeceutical, nutraceutical, etc. Moreover, seaweed-based cosmetic products are risen up in their demands by the consumers, as they see them as a promising alternative to synthetic cosmetics. Normally it contains purified biologically active compounds or extracts with several compounds. Several seaweed ingredients that are useful in cosmeceuticals are known to be effective alternatives with significant benefits. Many seaweeds' species demonstrated skin beneficial activities, such as antioxidant, anti-melanogenesis, antiaging, photoprotection, anti-wrinkle, moisturizer, antioxidant, anti-inflammatory, anticancer and antioxidant properties, as well as certain antimicrobial activities, such as antibacterial, antifungal and antiviral activities. This review presents applications of bioactive molecules derived from marine algae as a potential substitute for its current applications in the cosmetic industry. The biological activities of carbohydrates, proteins, phenolic compounds and pigments are discussed as safe sources of ingredients for the consumer and cosmetic industry.

Seaweed polysaccharides: Emerging extraction technologies, chemical modifications and bioactive properties

Nowadays, consumers are increasingly aware of the relationship between diet and health, showing a greater preference of products from natural origin. In the last decade, seaweeds have outlined as one of the natural sources with more potential to obtain bioactive carbohydrates. Numerous seaweed polysaccharides have aroused the interest of the scientific community, due to their biological activities and their high potential on biomedical, functional food and technological applications. To obtain polysaccharides from seaweeds, it is necessary to find methodologies that improve both yield and quality and that they are profitable. Nowadays, environmentally friendly extraction technologies are a viable alternative to conventional methods for obtaining these products, providing several advantages like reduced number of solvents, energy and time. On the other hand, chemical modification of their structure is a useful approach to improve their solubility and biological properties, and thus enhance the extent of their potential applications since some uses of polysaccharides are still limited. The present review aimed to compile current information about the most relevant seaweed polysaccharides, available extraction and modification methods, as well as a summary of their biological activities, to evaluate knowledge gaps and future trends for the industrial applications of these compounds.Key teaching pointsStructure and biological functions of main seaweed polysaccharides.Emerging extraction methods for sulfate polysaccharides.Chemical modification of seaweeds polysaccharides.Potential industrial applications of seaweed polysaccharides.Biological activities, knowledge gaps and future trends of seaweed polysaccharides.

The development of analytical methods for the purity determination of fucoidan extracted from brown seaweed species

To determine the purity of extracted fucoidan from brown seaweeds, analytical methods were developed, including spectroscopy (i.e., Attenuate total reflectance (ATR) - Fourier-transform infrared (FT-IR) and Raman) combined with chemometrics; and the results were compared with those of high performance liquid chromatography (HPLC) and other two chemistry methods (i.e., fucoidan estimation based on fucose content and a cationic dye method based on sulphated polysaccharide estimation). Quantitative models (i.e., partial least squares regression (PLSR)) were developed and cross-validated using FT-IR spectroscopic methods (R2CV ~ 0.998, RMSECV ~1.7%). The models were also validated using other four commercial fucoidan products. On the other hand, the same commercial samples were used to validate the two chemistry methods and the HPLC method. Estimation results of these analytical methods were discussed based on the potential of these analytical methods for fucoidan purity determination. The results demonstrated FT-IR spectroscopy with chemometrics potentially could be used for non-destructive and real time determination.

Seaweeds Compounds: An Ecosustainable Source of Cosmetic Ingredients?

Seaweed-based cosmetics are being gradually used by consumers as a substitute of synthetic equivalent products. These seaweed-based products normally contain purified compounds or extracts with several compounds. Several seaweeds’ molecules already demonstrated a high potential as a cosmetic active ingredient (such as, mycosporine-like amino acids, fucoidan, pigments, phenolic compounds) or as a key element for the products consistency (agar, alginate, carrageenan). Moreover, seaweeds’ compounds present important qualities for cosmetic application, such as low cytotoxicity and low allergens content. However, seaweeds’ biochemical profile can be variable, and the extraction methods can cause the loss of some of the biomolecules. This review gives a general look at the seaweed cosmetics benefits and its current application in the cosmetic industry. Moreover, it focuses on the ecological and sustainable scope of seaweed exploitation to guarantee a safe source of ingredients for the cosmetic industry and consumers.

Extraction Improvement of the Bioactive Blue-Green Pigment "Marennine" from Diatom Haslea ostrearia's Blue Water: A Solid-Phase Method Based on Graphitic Matrices

The compound “marennine” is a blue–green pigment produced by the benthic microalgae Haslea ostrearia, with pathogenicity reduction activities against some bacteria and promising potential as a natural pigment in seafood industries. After decades of research, the chemical family of this compound still remains unclear, mainly because structural studies were impaired by the presence of co-extracted compounds in marennine isolates. To improve the purity of marennine extract, we developed a novel extraction method using a graphitic stationary phase, which provides various advantages over the previous procedure using tandem ultrafiltration. Our method is faster, more versatile, provides a better crude yield (66%, compared to 57% for ultrafiltration) and is amenable to upscaling with continuous photobioreactor cultivation. Our goal was to take advantage of the modulable surface properties of the graphitic matrix by optimizing its interactions with marennine. As such, the effects of organic modifiers, pH and reducing agents were studied. With this improvement on marennine purification, we achieved altogether the isolation of a fucoidan-related, sulfated polysaccharide from blue water. Characterization of the polysaccharides fraction suggests that roughly half of UV-absorbing compounds could be isolated from the marennine crude extracts. The identification of sulfated polysaccharides could be a major breakthrough for marennine purification, providing targeted isolation techniques. Likewise, the added value of Haslea ostrearia and the role of polysaccharides in previous marennine chemical characterization and bioactivity studies remain to be determined.

Progress in Modern Marine Biomaterials Research

The growing demand for new, sophisticated, multifunctional materials has brought natural structural composites into focus, since they underwent a substantial optimization during long evolutionary selection pressure and adaptation processes. Marine biological materials are the most important sources of both inspiration for biomimetics and of raw materials for practical applications in technology and biomedicine. The use of marine natural products as multifunctional biomaterials is currently undergoing a renaissance in the modern materials science. The diversity of marine biomaterials, their forms and fields of application are highlighted in this review. We will discuss the challenges, solutions, and future directions of modern marine biomaterialogy using a thorough analysis of scientific sources over the past ten years.

Fucoidan Characterization: Determination of Purity and Physicochemical and Chemical Properties

Fucoidans are marine sulfated biopolysaccharides that have heterogenous and complicated chemical structures. Various sugar monomers, glycosidic linkages, molecular masses, branching sites, and sulfate ester pattern and content are involved within their backbones. Additionally, sources, downstream processes, and geographical and seasonal factors show potential effects on fucoidan structural characteristics. These characteristics are documented to be highly related to fucoidan potential activities. Therefore, numerous chemical qualitative and quantitative determinations and structural elucidation methods are conducted to characterize fucoidans regarding their physicochemical and chemical features. Characterization of fucoidan polymers is considered a bottleneck for further biological and industrial applications. Consequently, the obtained results may be related to different activities, which could be improved afterward by further functional modifications. The current article highlights the different spectrometric and nonspectrometric methods applied for the characterization of native fucoidans, including degree of purity, sugar monomeric composition, sulfation pattern and content, molecular mass, and glycosidic linkages.

Fucoidan: Biological Activity in Liver Diseases

Fucoidan is a type of polysaccharide rich in sulfuric acid groups and is mainly found in brown algae. Due to its extensive biological activities, such as anticoagulant, antitumor, antithrombotic, antiviral, anti-oxidant and enhancing immune function, fucoidan has gradually become a research hotspot. Under the scientific guidance of modern medical theory, fucoidan and its mechanism in oxidative stress, carbohydrate and lipid metabolism, inflammatory response, tumor proliferation, and metastasis have become a new research direction and an important basis as an effective liver protection drug. In this paper, we discuss the important role of fucoidan in viral hepatitis, liver fibrosis, liver cancer, nonalcoholic fatty liver and liver injury induced by drugs and ischemia and briefly discuss its underlying mechanism. We supplement the theoretical basis for its clinical application and provide effective targets for the development of follow-up dominant drugs.

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.

Therapeutic Uses of Red Macroalgae

Red Seaweed “Rhodophyta” are an important group of macroalgae that include approximately 7000 species. They are a rich source of structurally diverse bioactive constituents, including protein, sulfated polysaccharides, pigments, polyunsaturated fatty acids, vitamins, minerals, and phenolic compounds with nutritional, medical, and industrial importance. Polysaccharides are the main components in the cell wall of red algae and represent about 40–50% of the dry weight, which are extensively utilized in industry and pharmaceutical compounds, due to their thickening and gelling properties. The hydrocolloids galactans carrageenans and agars are the main red seaweed cell wall polysaccharides, which had broad-spectrum therapeutic characters. Generally, the chemical contents of seaweed are different according to the algal species, growth stage, environment, and external conditions, e.g., the temperature of the water, light intensity, nutrient concentrations in the ecosystem. Economically, they can be recommended as a substitute source for natural ingredients that contribute to a broad range of bioactivities like cancer therapy, anti-inflammatory agents, and acetylcholinesterase inhibitory. This review touches on the main points of the pharmaceutical applications of red seaweed, as well as the exploitation of their specific compounds and secondary metabolites with vital roles.

Molecular Targets and Related Biologic Activities of Fucoidan: A Review

Fucoidan-a marine natural active polysaccharide derived from brown algae with a variety of medicinal activities and low toxicity-has been used as clinical drug for renal diseases for nearly 20 years. The pharmacological mechanism of fucoidan has been well-investigated, based on target molecules and downstream signaling pathways. This review summarizes some important molecular targets of fucoidan and its related biologic activities, including scavenger receptor (SR), Toll-like receptors (TLRs), C-type lectin (CLEC) and some newly found target molecules, which may be beneficial for further understanding the pharmacological mechanism of fucoidan and discovering its new functions, as well as developing related clinical or adjuvant drugs and functional preparations.

A holistic zero waste biorefinery approach for macroalgal biomass utilization: A review

The growing concerns over the depleting fossil fuels and increase in the release of greenhouse gas emissions have necessitated the search for the potential biomass source for alternative energy generation. In this context, third generation biomass specifically maroalgae has gained a lot of research interest in the recent years for energy and products generation such as ethanol, butanol, alginates, agars, and carrageenans. There are a few reviews available in scientific domain on macroalgal biomass utilization for bioethanol production but none of them has addressed precisely from phenolic precursor compounds to the entire ethanol production process and its bottlenecks. Here, we explained critically the processes involved in bioethanol, value added products and chemicals production utilizing macroalgal biomass as a feedstock along with its zero waste feasibility approach. Apart from this, we have also summarized the major issues linked to the macroalgae based biofuels and bioproducts generation processes and their possible corrective measures. Biorefinery is a promising way to generate multiple products from a single source with short processing time. Thus, this review also focuses on the recent advancement in the macroalgal biomass scaling up and how this could help in the growth of macroalgal biorefinery industry in the near future.

The anti-cancer effects of fucoidan: a review of both in vivo and in vitro investigations

Fucoidan is a kind of the polysaccharide, which comes from brown algae and comprises of sulfated fucose residues. It has shown a large range of biological activities in basic researches, including many elements like anti-inflammatory, anti-cancer, anti-viral, anti-oxidation, anticoagulant, antithrombotic, anti-angiogenic and anti-Helicobacter pylori, etc. Cancer is a multifactorial disease of multiple causes. Most of the current chemotherapy drugs for cancer therapy are projected to eliminate the ordinary deregulation mechanisms in cancer cells. Plenty of wholesome tissues, however, are also influenced by these chemical cytotoxic effects. Existing researches have demonstrated that fucoidan can directly exert the anti-cancer actions through cell cycle arrest, induction of apoptosis, etc., and can also indirectly kill cancer cells by activating natural killer cells, macrophages, etc. Fucoidan is used as a new anti-tumor drug or as an adjuvant in combination with an anti-tumor drug because of its high biological activity, wide source, low resistance to drug resistance and low side effects. This paper reviews the mechanism by which fucoidan can eliminate tumor cells, delay tumor growth and synergize with anticancer chemotherapy drugs in vitro, in vivo and in clinical trials.

Caenorhabditis elegans as an in vivo model to assess fucoidan bioactivity preventing Helicobacter pylori infection

Currently, Helicobacter pylori is the unique biological carcinogenic agent. The search for antimicrobial alternatives to antibiotics against this pathogen has been categorized as a priority due to the drastic failure associated with current applied antibiotic therapy. The present study assessed the bioactive antimicrobial capability of fucoidan ("Generally Recognized as Safe" approval - European Commission December 2017) from different species of Phaeophyceae algae (Fucus vesiculosus, Undaria pinnatifida, Macrocystis pyrifera) against H. pylori. All the studied fucoidans showed bacteriostatic and bactericidal effects at the studied concentrations [5-100] μg ml-1 and exposure times [0-7 days]. The most effective anti-H. pylori fucoidan was validated in Caenorhabditis elegans as an in vivo model. C. elegans feed was supplemented with Undaria pinnatifida [0-100] μg ml-1 fucoidan, resulting in a significant improvement in lifespan, lowered H. pylori concentration in the digestive tract, and increased egg-laying pattern. New research lines proposing this compound as an active agent in nutraceutical and preventive novel therapies should be opened.

Fucoidans: Downstream Processes and Recent Applications

Fucoidans are multifunctional marine macromolecules that are subjected to numerous and various downstream processes during their production. These processes were considered the most important abiotic factors affecting fucoidan chemical skeletons, quality, physicochemical properties, biological properties and industrial applications. Since a universal protocol for fucoidans production has not been established yet, all the currently used processes were presented and justified. The current article complements our previous articles in the fucoidans field, provides an updated overview regarding the different downstream processes, including pre-treatment, extraction, purification and enzymatic modification processes, and shows the recent non-traditional applications of fucoidans in relation to their characters.

Marine oligosaccharides originated from seaweeds: Source, preparation, structure, physiological activity and applications

Marine polysaccharides originated from seaweeds, including agar, alginate, carrageenan, and fucoidan, possess various kinds of physiological activities and have been widely used in food, agricultural and medical areas. However, the application has been greatly limited by their poor solubility and low bioavailability. Thus marine oligosaccharides, as the degradation products of those polysaccharides, have drawn increasing attentions due to their obvious biological activities, good solubility and excellent bioavailability. This review will summarize the recent advances on the source, molecular structure and physiological activity of marine oligosaccharides, emphasizing their application as functional food additives. Furthermore, the relationship between the structure and the physiological activity of marine oligosaccharides is also elucidated and highlighted. The review concludes with an outlook toward potential applications for preparing the functional oligosaccharides in food biotechnology and agriculture fields.

Antimicrobial lead compounds from marine plants

Marine environment is a home to a very wide diversity of flora and fauna, which includes an array of genetically diverse coastline and under seawater plant species, animal species, microbial species, their habitats, ecosystems, and supporting ecological processes. The Earth is home to an estimated 10 million species, of which a large chunk belongs to marine environment. Marine plants are a store house of a variety of antimicrobial compounds like classes of marine flavonoids—flavones and flavonols, terpenoids, alkaloids, peptides, carbohydrates, fatty acids, polyketides, polysaccharides, phenolic compounds, and steroids. Lot of research today is directed toward marine species, which have proved to be a potent source of structurally widely diverse and yet highly bioactive secondary metabolites. Varied species of phylum Porifera, algae including diatoms, Chlorophyta, Euglenophyta, Dinoflagellata, Chrysophyta, cyanobacteria, Rhodophyta, and Phaeophyta, bacteria, fungi, and weeds have been exploited by mankind for their inherent indigenous biological antimicrobial compounds, produced under the extreme stressful underwater conditions of temperature, atmospheric pressure, light, and nutrition. The present study aims at presenting a brief review of bioactive marine compounds possessing antimicrobial potency.

Inhibitory effects of fucoidan on NMDA receptors and l-type Ca2+ channels regulating the Ca2+ responses in rat neurons

CONTEXT

Fucoidan, a sulphated polysaccharide extracted from brown algae [Fucus vesiculosus Linn. (Fucaceae)], has multiple biological activities.

OBJECTIVE

The effects of fucoidan on Ca²⁺ responses of rat neurons and its probable mechanisms with focus on glutamate receptors were examined.

MATERIALS AND METHODS

The neurons isolated from the cortex and hippocampi of Wistar rats in postnatal day 1 were employed. The intracellular Ca²⁺ responses triggered by various stimuli were measured in vitro by Fura-2/AM. Fucoidan at 0.5 mg/mL or 1.5 mg/mL was applied for 3 min to determine its effects on Ca²⁺ responses. RT-PCR was used to determine the mRNA expression of neuron receptors treated with fucoidan at 0.5 mg/mL for 3 h.

RESULTS

The Ca²⁺ responses induced by NMDA were 100% suppressed by fucoidan, and those induced by Bay K8644 90% in the cortical neurons. However, fucoidan has no significant effect on the Ca²⁺ responses of cortical neurons induced by AMPA or quisqualate. Meanwhile, the Ca²⁺ responses of hippocampal neurons induced by glutamate, ACPD or adrenaline, showed only a slight decrease following fucoidan treatment. RT-PCR assays of cortical and hippocampal neurons showed that fucoidan treatment significantly decreased the mRNA expression of NMDA-NR1 receptor and the primer pair for l-type Ca²⁺ channels, PR1/PR2.

DISCUSSION AND CONCLUSIONS

Our data indicate that fucoidan suppresses the intracellular Ca²⁺ responses by selectively inhibiting NMDA receptors in cortical neurons and l-type Ca²⁺ channels in hippocampal neurons. A wide spectrum of fucoidan binding to cell membrane may be useful for designing a general purpose drug in future.

Chitosan-toluidine blue beads for purification of fucoidans

A simple and green method was developed to purify fucoidans from their crude extracts. The new method utilizes a genipin-crosslinked chitosan beads as a support matrix for toluidine blue (TB). The modification of the mostly composed of d-glucosamine polymer was performed in one-step reaction to improve its mechanical stability and affinity to fucoidans. The adsorption kinetics and isotherm were investigated, which showed a maximum loading capacity (q_max) of 137.8 mg fucoidans/g wet beads. Moreover, the modified chitosan-TB beads were applied for purification of fucoidans from Fucus vesiculosus crude extract at different pH values, pH 1.0 and pH 6.0, producing two fractions: FC_1 and FC_6, respectively. The fractions were then characterized in comparison with crude and Sigma-Aldrich® purified product by FTIR and elemental analysis. The new method produced beads with higher loading capacity and used a natural crosslinker compared to the previously-reported methods.

Physicochemical Characteristics and Anticoagulant Activities of the Polysaccharides from Sea Cucumber Pattalus mollis

Sulfated polysaccharides from sea cucumbers possess distinct chemical structure and various biological activities. Herein, three types of polysaccharides were isolated and purified from Pattalus mollis, and their structures and bioactivities were analyzed. The fucosylated glycosaminoglycan (PmFG) had a CS-like backbone composed of the repeating units of {-4-d-GlcA-β-1,3-d-GalNAc4S6S-β-1-}, and branches of a sulfated α-l-Fuc (including Fuc2S4S, Fuc3S4S and Fuc4S with a molar ratio of 2:2.5:1) linked to O-3 of each d-GlcA. The fucan sulfate (PmFS) had a backbone consisting of a repetitively linked unit {-4-l-Fuc2S-α-1-}, and interestingly, every trisaccharide unit in its backbone was branched with a sulfated α-l-Fuc (Fuc4S or Fuc3S with a molar ratio of 4:1). Apart from the sulfated polysaccharides, two neutral glycans (PmNG-1 & -2) differing in molecular weight were also obtained and their structures were similar to animal glycogen. Anticoagulant assays indicated that PmFG and PmFS possessed strong APTT prolonging and intrinsic factor Xase inhibition activities, and the sulfated α-l-Fuc branches might contribute to the anticoagulant and anti-FXase activities of both PmFG and PmFS.

Degradation of Eight Sulfated Polysaccharides Extracted from Red and Brown Algae and Its Impact on Structure and Pharmacological Activities

Degradation represents a strategy to improve the biopharmaceutical properties of native algae sulfated polysaccharides (SP) with high M_w. The aim of this study was to compare the degradability of four sulfated xylogalactans (SXG) and four fucose-rich sulfated polysaccharides (FRSP) extracted from red and brown algae, respectively, using three simple methods causing no desulfation as well as to examine the chemical and pharmacological changes of the resulting fractions. The achieved degradation proved to be dependent on the basic glycan structure of the SP. Treatment with hydrogen peroxide (3%, 4 h, 50 °C) led to the most efficient degradation of both FRSP and SXG. The M_w decrease was associated with distinct reduction of the activities (complement inhibition (>) elastase inhibition > C1-INH potentiation) and resulted in a modified pharmacological profile. Despite their much lower degree of sulfation, some of the fractions with M_w < 15 kDa exhibited similar or even stronger activities than heparins, whereas they had only weak anticoagulant effects.

Recent Advances in Pharmaceutical Potential of Brown Algal Polysaccharides and their Derivatives

Marine plants, animals and microorganisms display steady growth in the ocean and are abundant carbohydrate resources. Specifically, natural polysaccharides obtained from brown algae have been drawing increasing attention owing to their great potential in pharmaceutical applications. This review describes the structural and biological features of brown algal polysaccharides, including alginates, fucoidans, and laminarins, and it highlights recently developed approaches used to obtain the oligo- and polysaccharides with defined structures. Functional modification of these polysaccharides promotes their advanced applications in biomedical materials for controlled release and targeted drug delivery, etc. Moreover, brown algal polysaccharides and their derivatives possess numerous biological activities with anticancer, anticoagulant, wound healing, and antiviral properties. In addition, we also discuss carbohydrate- based substrates from brown algae, which are currently in clinical and preclinical studies, as well as the marine drugs that are already on the market. The present review summarizes the recent development in carbohydratebased products from brown algae, with promising findings that could rapidly facilitate the future discovery of novel marine drugs.

Seaweeds as Source of Bioactive Substances and Skin Care Therapy—Cosmeceuticals, Algotheraphy, and Thalassotherapy

Riverine, estuarine, and coastal populations have always used algae in the development of home remedies that were then used to treat diverse health problems. The empirical knowledge of various generations originated these applications, and their mechanism of action is, in most cases, unknown, that is, few more scientific studies would have been described beyond simple collection and ethnographic recording. Nevertheless, recent investigations, carried out with the purpose of analyzing the components and causes that alter the functioning and the balance of our organism, are already giving their first results. Water, and especially sea water is considered as essential to life on our planet. It sings all the substances necessary and conducive to the development of the living being (minerals, catalysts, vitamins, amino acids, etc.). Oceans cover over 70% of Earth, being home to up to 90% of the organisms in the planet. Many rich resources and unique environments are provided by the ocean. Additionally, bioactive compounds that multiple marine organisms have a great potential to produce can be used as nutraceuticals, pharmaceuticals, and cosmeceuticals. Both primary and secondary metabolites are produced by algae. The first ones are directly implicated in development, normal growth, or reproduction conditions to perform physiological functions. Stress conditions, like temperature changes, salinity, environmental pollutants, or UV radiation exposure cause the performance of secondary metabolites. In algae, proteins, polysaccharides, fatty acids, and amino acids are primary metabolites and phenolic compounds, pigments, vitamins, sterols, and other bioactive agents, all produced in algae tissues, are secondary metabolites. These algal active constituents have direct relevance in cosmetics.

Novel Enzyme Actions for Sulphated Galactofucan Depolymerisation and a New Engineering Strategy for Molecular Stabilisation of Fucoidan Degrading Enzymes

Fucoidans from brown macroalgae have beneficial biomedical properties but their use as pharma products requires homogenous oligomeric products. In this study, the action of five recombinant microbial fucoidan degrading enzymes were evaluated on fucoidans from brown macroalgae: Sargassum mcclurei, Fucus evanescens, Fucus vesiculosus, Turbinaria ornata, Saccharina cichorioides, and Undaria pinnatifida. The enzymes included three endo-fucoidanases (EC 3.2.1.-GH 107), FcnA2, Fda1, and Fda2, and two unclassified endo-fucoglucuronomannan lyases, FdlA and FdlB. The oligosaccharide product profiles were assessed by carbohydrate-polyacrylamide gel electrophoresis and size exclusion chromatography. The recombinant enzymes FcnA2, Fda1, and Fda2 were unstable but were stabilised by truncation of the C-terminal end (removing up to 40% of the enzyme sequence). All five enzymes catalysed degradation of fucoidans containing α(1→4)-linked l-fucosyls. Fda2 also degraded S. cichorioides and U. pinnatifida fucoidans that have α(1→3)-linked l-fucosyls in their backbone. In the stabilised form, Fda1 also cleaved α(1→3) bonds. For the first time, we also show that several enzymes catalyse degradation of S. mcclurei galactofucan-fucoidan, known to contain α(1→4) and α(1→3) linked l-fucosyls and galactosyl-β(1→3) bonds in the backbone. These data enhance our understanding of fucoidan degrading enzymes and their substrate preferences and may assist development of enzyme-assisted production of defined fuco-oligosaccharides from fucoidan substrates.

The Sulfated Polysaccharides of Brown Algae and Products of Their Enzymatic Transformation as Potential Vaccine Adjuvants

The review is devoted to critical analysis of literature data, deal with effects and mechanisms of action of sulfated polysaccharides (PSs) – fucoidans from brown algae and products of their enzymatic transformation as potential adjuvants for enhancement of anti-infective and antitumor immune response. Numerous experimental data indicate that sulfated PSs demonstrate properties of vaccine adjuvants. Application perspectiveness of fucoidans as vaccine adjuvants is defined by their high biocompatibility, low-toxicity, safety and good tolerance by macroorganism, and also mechanisms of their immunomodulatory action. In particular, fucoidans are agonists of receptors of innate immunity and strong inducers of cellular and humoral immune response. At presenting the data of structural - functional interrelations, attention focused to the defining role of degree of sulfation, uronic acids and polyphenols contents, and also molecular mass in actions of fucoidans to innate and adaptive immunity cells. Insufficiency of literary data on studying of correlation of structure – physicochemical characteristics with adjuvanticities of the sulfated PSs, and also the problem of standardization of their active fractions are noted. Special attention is paid to the analysis of immunomodulatory and adjuvant activity of fucoidan oligosaccharides. Presented here results of experimental trial indicate that, despite the difficulties due to preparation of highly purified structurally characterized fractions and complex structure of fucoidans, these substances can be used as safe and effective adjuvants in vaccines against various pathogens including viruses, and also in antitumor vaccines.

Marine Carbohydrate-Based Compounds with Medicinal Properties

The oceans harbor a great diversity of organisms, and have been recognized as an important source of new compounds with nutritional and therapeutic potential. Among these compounds, carbohydrate-based compounds are of particular interest because they exhibit numerous biological functions associated with their chemical diversity. This gives rise to new substances for the development of bioactive products. Many are the known applications of substances with glycosidic domains obtained from marine species. This review covers the structural properties and the current findings on the antioxidant, anti-inflammatory, anticoagulant, antitumor and antimicrobial activities of medium and high molecular-weight carbohydrates or glycosylated compounds extracted from various marine organisms.

Size-dependent pharmacological activities of differently degraded fucoidan fractions from Fucus vesiculosus

Fucose-containing sulfated glycans (syn. fucoidans) from brown algae exhibit a wide range of bioactivities and are therefore considered promising candidates for health-supporting and medical applications. In this study, we investigated the pharmacological activities of fucoidan from Fucus vesiculosus and 18 gradually depolymerized fractions, which were obtained by hydrothermal and H2O2 treatment, respectively. All the activities decreased with decreasing molecular mass (Mw) but to a different extent resulting in some modified pharmacological profiles in dependence on the Mw as well as on the degradation method. H2O2 treatment was not only more efficient, simpler and cheaper than hydrothermal degradation, but also led to superior activity profiles and additionally eliminated co-extracted contaminants. Compared to heparin, the prime example of biologically active sulfated glycans, evenly sized H2O2 fractions exhibited considerable effects being relevant for anti-inflammatory activity, however only negligible anticoagulant activity and FXII activating potency. Due to their improved biopharmaceutical characteristics and favorable activities, degraded fucoidan fractions are worth to be further investigated as anti-inflammatory and anticomplementary agents.