Antibacterial Properties of Fucoidans from the Brown Algae Fucus vesiculosus L. of the Barents Sea

A comprehensive review to assess the potential, health benefits and complications of fucoidan for developing as functional ingredient and nutraceutical

Polysaccharides from seaweeds or macroalgae are garnering significant interest from pharmaceutical and food industries due to their bioactivities and promising therapeutic effects. Among the diverse agal polysaccharides, fucoidan is a well-documented and stands out as a well-researched sulphated heteropolysaccharide found in brown seaweeds. It primarily consists of l-fucose and sulfate ester groups, along with other monosaccharides like xylose, mannose, uronic acid, rhamnose, arabinose, and galactose. Recent scientific investigations have unveiled the formidable inhibitory prowess of fucoidan against SARS-CoV-2, offering a promising avenue for therapeutic intervention in our current landscape. Moreover, fucoidan has demonstrated remarkable abilities in safeguarding the gastrointestinal tract, regulating angiogenesis, mitigating metabolic syndrome, and fortifying bone health. Despite the abundance of studies underscoring fucoidan's potential as a vital component sourced from nature, its exploitation remains constrained by inherent limitations. Thus, the primary objective of this article is to furnish a comprehensive discourse on the structural attributes, health-enhancing properties, safety parameters, and potential toxicity associated with fucoidan. Furthermore, the discourse extends to elucidating the practical applications and developmental prospects of fucoidan as a cornerstone in the realm of functional foods and nutraceuticals.

Application of Ulva lactuca polysaccharide in the preservation of refrigerated of Lateolabrax maculatus fillets

This study aimed to explore the use of Ulva lactuca polysaccharide (ULP) as a preservative for perch (Lateolabrax maculatus) fillets stored under refrigeration at 4 °C. Fresh perch fillets were treated with ULP (7-10 kDa) and potassium sorbate, respectively, to evaluate their effectiveness in inhibiting bacterial growth and maintain freshness. A 0.5% ULP solution significantly decreased the pH value, total volatile basic nitrogen value, thiobarbituric acid value, and total bacterial count of perch fillets. ULP solution delayed the changes in whiteness and texture of fillets, as well as protein degradation. The acute toxicity experiment further evaluates the safety and reliability of ULP. Simultaneously, utilizing 16S rRNA techniques, the ULP solution inhibited microorganisms known for their strong spoilage capabilities, such as Pseudomonas, Actinetobacter, and Shewanella. Microorganisms with a weaker ability to cause corruption became the dominant bacteria, such as Acetobacter, Lactobacillus, and Faecalibacterium, thereby exerting a degree of inhibition against spoilage.

Fucoidan-based coatings extend the shelf-life of nectarines

This research investigated the efficacy of fucoidan-based coatings in preserving nectarine fruits at room temperature. The present study compared the preservation effects of different fucoidan concentrations (1%, 3%, 5%) with distilled water serving as a control (0%). The findings revealed that the addition of fucoidan dose-dependently improved the room temperature preservation quality of the nectarines. Notably, a 5% fucoidan concentration markedly delays the onset of the respiratory peak in nectarines. On day 14 of storage, the plants were subsequently cultured on a 5% fucoidan coating (F5), which exhibited a weight loss rate of 5.87%, a spoilage rate of 18.33%, a hardness of 3.87 kg/cm², a soluble solid content of 11.47%, a titratable acid content of 0.29% and an ascorbic acid content of 2.58%. The overall acceptability score was 7.83. These results demonstrated that coating with fucoidan is an effective method for the preservation of nectarines.

Structural characterization and human gut microbiota fermentation in vitro of a polysaccharide from Fucus vesiculosus

In this study, an acidic polysaccharide (FVP-7 A) was isolated from Fucus vesiculosus by DEAE-Sepharose™ fast flow. The chemical composition, glycosidic bonds and in vitro fecal fermentation characteristics of FVP-7 A were studied. Results shown that FVP-7 A was a homogenous polysaccharide with average molecular weight of 30.94 kDa. Combined with FT-IR, monosaccharide composition, methylation and NMR analysis, the glycosidic bonds of FVP-7 A mainly composed of →4)-β-D-Manp-(1→, →3)-α-L-Fucp-(1→, α-D-Manp-(1→, →3)-β-D-Manp-(1 → and →4,6)-α-D-Manp-(1→. The zeta potential and atomic force microscopy images indicated that FVP-7 A could exist stably as a single chain-like structure in dilute solution. After gut fermentation, FVP-7 A was utilized and promoted multiple short-chain fatty acids production, especially acetic acid, butyric acid and valeric acid. For prebiotics, FVP-7 A significantly increased the relative abundance of short-chain fatty acids producing bacteria such as Bacteroides, Lachnospira, Faecalibacterium, Ruminococcus, Oscillospira and Dialister, and inhiited the growth of the harmful bacteria Shigella. These results indicated that FVP-7 A could be used as a potential dietary supplement to improve intestinal health.

Bilayer coatings for extension of the shelf life of fish fillets: Incorporating seaweed sulfated polysaccharides in chitosan-alginate LbL structures

The aim of this study was to develop a new active coating of layer-by-layer (LbL) structure composed of alginate (as polyanions) and chitosan (as a polycation) containing sulfated polysaccharide (fucoidan) from Sargassum angustifolium, to protect rainbow trout fillets during refrigerated storage. Chitosan and alginate do not combine with each other as a homogeneous solution, so they are suitable for multilayer coatings. The results demonstrated that coating samples with chitosan and fucoidan significantly improved the quality of fish fillets and extended their shelf life from 6 to 16 days. The chemical values (TBARS and TVB-N) and bacterial growth (total viable count (TVC), total psychrophilic count (PTC), and lactic acid bacteria (LAB)) indicated lower levels in the LbL coating samples containing fucoidan compared to the alginate and control samples. Among the different coating samples, the LbL coating with fucoidan (AChF1) exhibited lower weight loss, improved chromaticity (L*, a*, and b*), and minimal changes in mechanical and sensory evaluations. Based on the findings, AChF1 was the most effective treatment for increasing the shelf life of rainbow trout fillets during refrigerated storage. Therefore, it has potential applications in the food packaging industry.

Fucoidan's Molecular Targets: A Comprehensive Review of Its Unique and Multiple Targets Accounting for Promising Bioactivities Supported by In Silico Studies

Fucoidan is a class of multifunctional polysaccharides derived from marine organisms. Its unique and diversified physicochemical and chemical properties have qualified them for potential and promising pharmacological uses in human diseases, including inflammation, tumors, immunity disorders, kidney diseases, and diabetes. Physicochemical and chemical properties are the main contributors to these bioactivities. The previous literature has attributed such activities to its ability to target key enzymes and receptors involved in potential disease pathways, either directly or indirectly, where the anionic sulfate ester groups are mainly involved in these interactions. These findings also confirm the advantageous pharmacological uses of sulfated versus non-sulfated polysaccharides. The current review shall highlight the molecular targets of fucoidans, especially enzymes, and the subsequent responses via either the upregulation or downregulation of mediators' expression in various tissue abnormalities. In addition, in silico studies will be applied to support the previous findings and show the significant contributors. The current review may help in understanding the molecular mechanisms of fucoidan. Also, the findings of this review may be utilized in the design of specific oligomers inspired by fucoidan with the purpose of treating life-threatening human diseases effectively.

Physicochemical and functional characterization of gelatin edible film incorporated with fucoidan isolated from Sargassum tenerrimum

Biodegradable films were created with fish gelatin and fucoidan extracted from Sargassum tenerrimum using 30% glycerol as a plasticizer. The gelatin films were incorporated with fucoidan (2.5%, 5%, 7.5%, and 10%), respectively. Results presented that the average thickness of films ranged from 0.12 to 0.147 mm. Tensile strength (TS) was decreased from 29.27 to 3.46 MPa by adding the fucoidan except for the gelatin/fucoidan 10% (5.35 MPa) sample. The results showed that the physical characteristics (the contact angle (Ɵ), water solubility, opacity, and moisture content) of the films significantly changed depending on different fucoidan concentrations. FTIR and SEM analysis confirmed the interaction of fucoidan with gelatin in the composite film. Furthermore, adding 10% fucoidan showed high DPPH radical scavenging activity (65%) than other treatments. Therefore, incorporation of fucoidan extracted from brown algae (Sargassum tenerrimum) with fish gelatin films improved thermal stability, anti-oxidative, and antibacterial characteristics in addition to enhanced mechanical and protective properties, to be used as a bioactive edible film in the food packaging industry.

Building Fucoidan/Agarose-Based Hydrogels as a Platform for the Development of Therapeutic Approaches against Diabetes

Current management for diabetes has stimulated the development of versatile 3D-based hydrogels as in vitro platforms for insulin release and as support for the encapsulation of pancreatic cells and islets of Langerhans. This work aimed to create agarose/fucoidan hydrogels to encapsulate pancreatic cells as a potential biomaterial for diabetes therapeutics. The hydrogels were produced by combining fucoidan (Fu) and agarose (Aga), marine polysaccharides derived from the cell wall of brown and red seaweeds, respectively, and a thermal gelation process. The agarose/fucoidan (AgaFu) blended hydrogels were obtained by dissolving Aga in 3 or 5 wt % Fu aqueous solutions to obtain different proportions (4:10; 5:10, and 7:10 wt). The rheological tests on hydrogels revealed a non-Newtonian and viscoelastic behavior, while the characterization confirmed the presence of the two polymers in the structure of the hydrogels. In addition, the mechanical behavior showed that increasing Aga concentrations resulted in hydrogels with higher Young's modulus. Further, the ability of the developed materials to sustain the viability of human pancreatic cells was assessed by encapsulation of the 1.1B4HP cell line for up to 7 days. The biological assessment of the hydrogels revealed that cultured pancreatic beta cells tended to self-organize and form pseudo-islets during the period studied.

The Potential of Algae in the Nutricosmetic Sector

Seaweeds or algae are marine autotrophic organisms. They produce nutrients (e.g., proteins, carbohydrates, etc.) essential for the survival of living organisms as they participate in biochemical processes and non-nutritive molecules (such as dietary fibers and secondary metabolites), which can improve their physiological functions. Seaweed polysaccharides, fatty acids, peptides, terpenoids, pigments, and polyphenols have biological properties that can be used to develop food supplements and nutricosmetic products as they can act as antibacterial, antiviral, antioxidant, and anti-inflammatory compounds. This review examines the (primary and secondary) metabolites produced by algae, the most recent evidence of their effect on human health conditions, with particular attention to what concerns the skin and hair's well-being. It also evaluates the industrial potential of recovering these metabolites from biomass produced by algae used to clean wastewater. The results demonstrate that algae can be considered a natural source of bioactive molecules for well-being formulations. The primary and secondary metabolites' upcycling can be an exciting opportunity to safeguard the planet (promoting a circular economy) and, at the same time, obtain low-cost bioactive molecules for the food, cosmetic, and pharmaceutical industries from low-cost, raw, and renewable materials. Today's lack of methodologies for recovering bioactive molecules in large-scale processes limits practical realization.

Inhibitory effects of fucoidan from Laminaria japonica against some pathogenic bacteria and SARS-CoV-2 depend on its large molecular weight

Fucoidan is a highly sulfated polysaccharide with a wide range of bioactivities, including anti-pathogenic activity. However, the relationship between structure and activity of fucoidan in inhibiting pathogen infections remains unclear. Here, different-molecular-weight fucoidans were prepared by photocatalytic degradation followed by membrane ultrafiltration, and their chemical structures and anti-pathogenic microbiota activity were compared. Results showed that photocatalytic degradation could effectively degrade fucoidan while its structure block and sulfate groups were not destroyed obviously. Fucoidan (90.8 kDa) of 5 mg/mL could inhibit the growth of S. aureus, S. typhimurium and E. coli, but its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), demonstrated lower inhibitory effect. In addition, compared to Dfuc1 and Dfuc2, fucoidan showed stronger capability to prevent the adhesion of S. aureus, L. monocytogenes, V. parahaemolyticus and S. typhimurium to HT-29 cells. Moreover, the inhibitory effect against SARS-CoV-2 and the binding activity to S protein were also positively correlated to molecular weight. These results indicate that natural fucoidan with higher molecular weight are more effective to inhibit these pathogenic bacteria and SARS-CoV-2, providing a better understanding of the relationship between structure and activity of fucoidan against pathogenic microbiota.

Unveiling the secrets of marine-derived fucoidan for bone tissue engineering-A review

Biomedical uses for natural polysaccharides of marine origin are growing in popularity. The most prevalent polysaccharides, including alginates, agar, agarose and carrageenan, are found in seaweeds. One among these is fucoidan, which is a sulfated polysaccharide derived from brown algae. Compared to many of the biomaterials of marine origin currently in research, it is more broadly accessible and less expensive. This polysaccharide comes from the same family of brown algae from which alginate is extracted, but has garnered less research compared to it. Although it was the subject of research beginning in the 1910's, not much has been done on it since then. Few researchers have focused on its potential for biomedical applications; nevertheless, a thorough knowledge of the molecular mechanisms behind its diverse features is still lacking. This review provides a quick outline of its history, sources, and organization. The characteristics of this potential biomaterial have also been explored, with a thorough analysis concentrating on its use in bone tissue engineering. With the preclinical research completed up to this point, the fucoidan research status globally has also been examined. Therefore, the study might be utilized as a comprehensive manual to understand in depth the research status of fucoidan, particularly for applications related to bone tissue engineering.

Fucoid brown algae inject fucoidan carbon into the ocean

Brown algae annually convert gigatons of carbon dioxide into carbohydrates, including the complex extracellular matrix polysaccharide fucoidan. Due to its persistence in the environment, fucoidan is potentially a pathway for marine carbon sequestration. Rates of fucoidan secretion by brown algae remain unknown due to the challenge of identifying and quantifying complex polysaccharides in seawater. We adapted the techniques of anion exchange chromatography, enzyme-linked immunosorbent assay, and biocatalytic enzyme-based assay for detection and quantification of fucoidan. We found the brown alga Fucus vesiculosus at the Baltic Sea coast of south-west Finland to secrete 0.3% of their biomass as fucoidan per day. Dissolved fucoidan concentrations in seawater adjacent to algae reached up to 0.48 mg L-1. Fucoidan accumulated during incubations of F. vesiculosus, significantly more in light than in darkness. Maximum estimation by acid hydrolysis indicated fucoidan secretion at a rate of 28 to 40 mg C kg-1 h-1, accounting for 44 to 50% of all exuded dissolved organic carbon. Composed only of carbon, oxygen, hydrogen, and sulfur, fucoidan secretion does not consume nutrients enabling carbon sequestration independent of algal growth. Extrapolated over a year, the algae sequester more carbon into secreted fucoidan than their biomass. The global utility of fucoidan secretion is an alternative pathway for carbon dioxide removal by brown algae without the need to harvest or bury algal biomass.

Effect of Brown Algae and Lichen Extracts on the SCOBY Microbiome and Kombucha Properties

Kombucha tea was made by the fermentation of SCOBY culture of green tea broth with the addition of Fucus vesiculosus algae extract, Cetraria islandica lichen extract and their mixture. Kombucha was also made without the herbal supplements as a control. After 11 days of fermentation, in addition to the yeast Brettanomyces bruxellensis and the bacteria Komagataeibacter rhaeticus and Komagataeibacter hansenii contained in all of the samples, the yeast Zygosaccharomyces bailii and bacteria Komagataeibacter cocois were detected in the samples with the herbal extracts. In all of the kombucha with herbal additives, the total fraction of yeast was decreased as compared to the control. The total content of polyphenols and the antioxidant activity of the beverages with and without the addition of herbal extracts were comparable. The kombucha made with the algae extract showed an increased content of sucrose and organic acids, while the fructose and glucose content in the samples with algae and the mixture of extracts were lower than in the other samples. The samples with the algae extract had the highest organoleptic indicators "aroma", "clarity" and "acidity", while the control samples had slightly higher indicators of "taste" and "aftertaste". The results of this study indicate the potential of algae and lichens as functional supplements for obtaining non-alcoholic fermented beverages with additional nutraceutical value.

Brown Macroalgae (Phaeophyceae): A Valuable Reservoir of Antimicrobial Compounds on Northern Coast of Spain

The search for new sources of antimicrobial compounds has become an urgent need, due to the threat that the spread of bacterial resistance represents for global health and food safety. Brown macroalgae have been proposed as a great reservoir in the search for novel antimicrobial compounds. In this study, mid-polarity extracts were performed with a selection of 20 brown macroalgae species from northern Spain. The total polyphenol, carbohydrate and protein contents were quantified by spectrophotometry. The volatile organic compounds (VOCs) of whole macroalgae were also studied as a biomarker of their metabolic state in the representative species of the tested families by gas chromatography-mass spectrometry (GC-MS). The antimicrobial potential of the extracts was assessed by a disk diffusion assay against 20 target bacteria and further determinations of the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were performed by a microdilution assay for the active extracts. Ericaria selaginoides, Bifurcaria bifurcata and Dictyota dichotoma showed an antimicrobial effect against six Gram-positive strains: Bacillus cereus, Bacillus subtilis, Geobacillus stearothermophilus, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus haemolyticus. The phenolic content was generally higher in the extracts that showed antimicrobial activity, followed by carbohydrates and low contents of proteins. The results obtained in this study reveal the potential of brown macroalgae as a promising alternative source of antimicrobial compounds as functional ingredients for the application in industrial fields.

Fucoidan-based nanoparticles: Preparations and applications

Nanoparticle-based therapy has gained much attention in the pharmaceutical industry. Fucoidan is a sulfated polysaccharide naturally derived from marine brown algae and is widely used for medical applications. We explore preparation of fucoidan-based nanoparticles and their biomedical applications in the current review. The fucoidan-based nanoparticles have been synthesized using microwave, emulsion, solvent evaporation, green synthesis, polyelectrolyte self-assembly, precipitation, and ultrasonication methods. The synthesized nanoparticles have particle sizes ranging from 100 to 400 nm. Therefore, fucoidan-based nanoparticles have a variety of potential therapeutic applications, including drug delivery, cancer therapies, tissue engineering, antimicrobial applications, magnetic resonance imaging contrast, and atherothrombosis imaging. For example, fucoidan nanoparticles have been used to deliver curcumin, dextran, gentamicin, epigallocatechin gallate, and cisplatin for cancer therapies. Furthermore, fucoidan nanoparticles coupled with metal nanoparticles have been used to target and recognize clinical conditions for diagnostic purposes. Hence, fucoidan-based nanoparticles have been helpful for biomedical applications.

Furcellaran Surface Deposition and Its Potential in Biomedical Applications

Surface coatings of materials by polysaccharide polymers are an acknowledged strategy to modulate interfacial biocompatibility. Polysaccharides from various algal species represent an attractive source of structurally diverse compounds that have found application in the biomedical field. Furcellaran obtained from the red algae Furcellaria lumbricalis is a potential candidate for biomedical applications due to its gelation properties and mechanical strength. In the present study, immobilization of furcellaran onto polyethylene terephthalate surfaces by a multistep approach was studied. In this approach, N-allylmethylamine was grafted onto a functionalized polyethylene terephthalate (PET) surface via air plasma treatment. Furcellaran, as a bioactive agent, was anchored on such substrates. Surface characteristics were measured by means of contact angle measurements, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Subsequently, samples were subjected to selected cell interaction assays, such as antibacterial activity, anticoagulant activity, fibroblasts and stem cell cytocompatibility, to investigate the Furcellaran potential in biomedical applications. Based on these results, furcellaran-coated PET films showed significantly improved embryonic stem cell (ESC) proliferation compared to the initial untreated material.

Phytochemical and Potential Properties of Seaweeds and Their Recent Applications: A Review

Since ancient times, seaweeds have been employed as source of highly bioactive secondary metabolites that could act as key medicinal components. Furthermore, research into the biological activity of certain seaweed compounds has progressed significantly, with an emphasis on their composition and application for human and animal nutrition. Seaweeds have many uses: they are consumed as fodder, and have been used in medicines, cosmetics, energy, fertilizers, and industrial agar and alginate biosynthesis. The beneficial effects of seaweed are mostly due to the presence of minerals, vitamins, phenols, polysaccharides, and sterols, as well as several other bioactive compounds. These compounds seem to have antioxidant, anti-inflammatory, anti-cancer, antimicrobial, and anti-diabetic activities. Recent advances and limitations for seaweed bioactive as a nutraceutical in terms of bioavailability are explored in order to better comprehend their therapeutic development. To further understand the mechanism of action of seaweed chemicals, more research is needed as is an investigation into their potential usage in pharmaceutical companies and other applications, with the ultimate objective of developing sustainable and healthier products. The objective of this review is to collect information about the role of seaweeds on nutritional, pharmacological, industrial, and biochemical applications, as well as their impact on human health.

The Biochemical Composition and Antioxidant Properties of Fucus vesiculosus from the Arctic Region

Fucus vesiculosus is one of the most prominent brown algae in the shallow waters of the seas of the Arctic region (Barents (BS), White (WS), Norwegian (NS), and Irminger (IS)). The aim of this study was to determine the biochemical composition of F. vesiculosus from the Arctic at different reproductive phases, and to evaluate the antioxidant properties of F. vesiculosus extracts. The amounts of monosaccharides, phlorotannins, flavonoids, and ash and the mineral composition significantly varied in the algae. A strong correlation was established between monosaccharide, phlorotannin, and flavonoid accumulation and water salinity (Pearson’s correlation coefficients r = −0.58, 0.83, and 0.44, respectively; p < 0.05). We noted a negative correlation between the antioxidant activity and the amount of the structural monosaccharides of fucoidan (r = −0.64). A positive correlation of phlorotannins and flavonoids with antioxidant power was confirmed for all samples. The ash accumulation was relatively lower in the sterile phase for the algae from the BS and WS. The correlation between the Metal Pollution Index (MPI) and the reproductive phases was medium with high fluctuation. Meanwhile, the MPI strongly correlated with the salinity and sampling site. The gradient of the MPI values across the sea was in the following ranking order: BS < WS < NS < IS. Taken together, and based on our data on the elemental contents of F. vesiculosus, we believe that this alga does not accumulate toxic doses of elements. Therefore, the Arctic F. vesiculosus could be safely used in food and drug development as a source of active biochemical compounds and as a source of dietary elements to cover the daily nutritional requirements of humans.

An Overview of Potential Seaweed-Derived Bioactive Compounds for Pharmaceutical Applications

Nowadays, seaweeds are widely involved in biotechnological applications. Due to the variety of bioactive compounds in their composition, species of phylum Ochrophyta, class Phaeophyceae, phylum Rhodophyta and Chlorophyta are valuable for the food, cosmetic, pharmaceutical and nutraceutical industries. Seaweeds have been consumed as whole food since ancient times and used to treat several diseases, even though the mechanisms of action were unknown. During the last decades, research has demonstrated that those unique compounds express beneficial properties for human health. Each compound has peculiar properties (e.g., antioxidant, antimicrobial, antiviral activities, etc.) that can be exploited to enhance human health. Seaweed’s extracted polysaccharides are already involved in the pharmaceutical industry, with the aim of replacing synthetic compounds with components of natural origin. This review aims at a better understanding of the recent uses of algae in drug development, with the scope of replacing synthetic compounds and the multiple biotechnological applications that make up seaweed’s potential in industrial companies. Further research is needed to better understand the mechanisms of action of seaweed’s compounds and to embrace the use of seaweeds in pharmaceutical companies and other applications, with the final scope being to produce sustainable and healthier products.

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.