Marine algae sulfated polysaccharides for tissue engineering and drug delivery approaches

Extraction and Purification of Biopolymers from Marine Origin Sources Envisaging Their Use for Biotechnological Applications

Biopolymers are a versatile and diverse class of materials that has won high interest due to their potential application in several sectors of the economy, such as cosmetics, medical materials/devices, and food additives. In the last years, the search for these compounds has explored a wider range of marine organisms that have proven to be a great alternative to mammal sources for these applications and benefit from their biological properties, such as low antigenicity, biocompatibility, and biodegradability, among others. Furthermore, to ensure the sustainable exploitation of natural marine resources and address the challenges of 3R's policies, there is a current necessity to valorize the residues and by-products obtained from food processing to benefit both economic and environmental interests. Many extraction methodologies have received significant attention for the obtention of diverse polysaccharides, proteins, and glycosaminoglycans to accomplish the increasing demands for these products. The present review gives emphasis to the ones that can be obtained from marine biological resources, as agar/agarose, alginate and sulfated polysaccharides from seaweeds, chitin/chitosan from crustaceans from crustaceans, collagen, and some glycosaminoglycans such as chondroitin sulfate and hyaluronic acids from fish. It is offered, in a summarized and easy-to-interpret arrangement, the most well-established extraction and purification methodologies used for obtaining the referred marine biopolymers, their chemical structure, as well as the characterization tools that are required to validate the extracted material and respective features. As supplementary material, a practical guide with the step-by-step isolation protocol, together with the various materials, reagents, and equipment, needed for each extraction is also delivered is also delivered. Finally, some remarks are made on the needs still observed, despite all the past efforts, to improve the current extraction and purification procedures to achieve more efficient and green methodologies with higher yields, less time-consuming, and decreased batch-to-batch variability.

Sulfated polysaccharide as biomimetic biopolymers for tissue engineering scaffolds fabrication: Challenges and opportunities

Sulfated polysaccharides play important roles in tissue engineering applications because of their high growth factor preservation ability and their native-like biological features. There are different sulfated polysaccharides based on different repeating units in the carbohydrate backbone, the position of the sulfate group, and the sulfation degree of the polysaccharide. These led to various sulfated polymers with different negative charge densities and resultant structure-property relationships. Since numerous reports are presented related to sulfated polysaccharide applications in tissue engineering, it is crucial to review the role of effective physicochemical and biological parameters in their usage; as well as their structure-property relationships. Within this review, we focused on the effect of naturally occurring and synthetic sulfated polysaccharides in tissue engineering applications reported in the last years, highlighting the challenges of the scaffold fabrication process, the position, and the degree of sulfate on biomedical activity. Additionally, we discussed their use in numerous in vitro and in vivo model systems.

Influence of Supplementation of Ecklonia cava Polyphenols on Learning, Memory, and Brain Fatty Acid Composition in Mice

AIMS

The objective of this study was to determine the effects of intake of polyphenols from Ecklonia cava on spatial task performance and nervous fatty acid composition in mice fed with a high-fat diet.

METHODS

Thirty mice were randomly divided into three groups; each group consisted of ten mice. The control group was fed 5% soybean oil as a fat source, whereas the high fat (HF) group was fed a 15% lard diet and the polyphenol (ECP) group was maintained on the HF diet plus 1% E. cava polyphenols.

RESULTS

The ECP group exhibited a short escape latency and better memory retention in the Morris water maze test compared with the control and HF groups (P<0.05). In addition, the ECP group showed a greater increase in avoidance latency than that of the HF group (P<0.05). Moreover, the consumption of polyphenols from E. cava presented higher levels of DHA in the brain and retina (P<0.05).

CONCLUSION

This study suggested the positive effects of polyphenols from E. cava on memory retention, which might be partially attributed to the increased levels of DHA in the brain.

Chemical Composition of Macroalgae Polysaccharides from Galician and Portugal Coasts: Seasonal Variations and Biological Properties

Crude polysaccharides extracted from the Codium sp. and Osmundea sp. macroalgae collected in different seasons (winter, spring and summer) from the Galician and North Portugal coasts were characterised, aiming to support their biomedical application to wound healing. An increase in polysaccharides' sulphate content was registered from winter to summer, and higher values were obtained for Osmundea sp. In turn, the monosaccharide composition constantly changed with a decrease in glucose in Osmundea sp. from spring to winter. For Codium sp., a higher increase was noticed regarding glucose content in the Galician and Portugal coasts. Galactose was the major monosaccharide in all the samples, remaining stable in all seasons and collection sites. These results corroborate the sulphate content and antioxidant activity, since the Osmundea sp.-derived polysaccharides collected in summer exhibited higher scavenging radical ability. The biocompatibility and wound scratch assays revealed that the Osmundea sp. polysaccharide extracted from the Portugal coast in summer possessed more potential for promoting fibroblast migration. This study on seasonal variations of polysaccharides, sulphate content, monosaccharide composition and, consequently, biological properties provides practical guidance for determining the optimal season for algae harvest to standardise preparations of polysaccharides for the biomedical field.

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.

A propitious role of marine sourced polysaccharides: Drug delivery and biomedical applications

Numerous compounds, with extensive applications in biomedical and biotechnological fields, are present in the oceans, which serve as a prime renewable source of natural substances, further promoting the development of novel medical systems and devices. Polysaccharides are present in the marine ecosystem in abundance, promoting minimal extraction costs, in addition to their solubility in extraction media, and an aqueous solvent, along with their interactions with biological compounds. Certain algae-derived polysaccharides include fucoidan, alginate, and carrageenan, while animal-derived polysaccharides comprise hyaluronan, chitosan and many others. Furthermore, these compounds can be modified to facilitate their processing into multiple shapes and sizes, as well as exhibit response dependence to external conditions like temperature and pH. All these properties have promoted the use of these biomaterials as raw materials for the development of drug delivery carrier systems (hydrogels, particles, capsules). The present review enlightens marine polysaccharides providing its sources, structures, biological properties, and its biomedical applications. In addition to this, their role as nanomaterials is also portrayed by the authors, along with the methods employed to develop them and associated biological and physicochemical properties designed to develop suitable drug delivery systems.

Advanced Polymeric Membranes as Biomaterials Based on Marine Sources Envisaging the Regeneration of Human Tissues

The self-repair capacity of human tissue is limited, motivating the arising of tissue engineering (TE) in building temporary scaffolds that envisage the regeneration of human tissues, including articular cartilage. However, despite the large number of preclinical data available, current therapies are not yet capable of fully restoring the entire healthy structure and function on this tissue when significantly damaged. For this reason, new biomaterial approaches are needed, and the present work proposes the development and characterization of innovative polymeric membranes formed by blending marine origin polymers, in a chemical free cross-linking approach, as biomaterials for tissue regeneration. The results confirmed the production of polyelectrolyte complexes molded as membranes, with structural stability resulting from natural intermolecular interactions between the marine biopolymers collagen, chitosan and fucoidan. Furthermore, the polymeric membranes presented adequate swelling ability without compromising cohesiveness (between 300 and 600%), appropriate surface properties, revealing mechanical properties similar to native articular cartilage. From the different formulations studied, the ones performing better were the ones produced with 3 % shark collagen, 3% chitosan and 10% fucoidan, as well as with 5% jellyfish collagen, 3% shark collagen, 3% chitosan and 10% fucoidan. Overall, the novel marine polymeric membranes demonstrated to have promising chemical, and physical properties for tissue engineering approaches, namely as thin biomaterial that can be applied over the damaged articular cartilage aiming its regeneration.

Polysaccharide-Based Composite Scaffolds for Osteochondral and Enthesis Regeneration

The rotator cuff and Achilles tendons along with the anterior cruciate ligament (ACL) are frequently injured with limited healing capacity. At the soft-hard tissue interface, enthesis is prone to get damaged and its regeneration in osteochondral defects is essential for complete healing. The current clinical techniques used in suturing procedures to reattach tendons to bones need much improvement for the generation of the native interface tissue, that is, enthesis, for patients to regain their full functions. Recently, inspired by the composite native tissue, much effort has been made to fabricate composite scaffolds for enthesis tissue regeneration. This review first focuses on the studies that used composite scaffolds for the regeneration of enthesis. Then, the use of polysaccharides for osteochondral tissue engineering is reviewed and their potential for enthesis regeneration is presented based on their supporting effects on osteogenesis and chondrogenesis. Gellan gum (GG) is selected and reviewed as a promising polysaccharide due to its unique osteogenic and chondrogenic activities that help avoid the inherent weakness of dissimilar materials in composite scaffolds. In addition, original preliminary results showed that GG supports collagen type I production and upregulation of osteogenic marker genes. Impact Statement Enthesis regeneration is essential for complete and functional healing of tendon and ligament tissues. Current suturing techniques to reattach the tendon/ligament to bones have high failure rates. This review highlights the studies on biomimetic scaffolds aimed to regenerate enthesis. In addition, the potential of using polysaccharides to regenerate enthesis is discussed based on their ability to regenerate osteochondral tissues. Gellan gum is presented as a promising biopolymer that can be modified to simultaneously support bone and cartilage regeneration by providing structural continuity for the scaffold.

Sustainable production of biofuels and bioderivatives from aquaculture and marine waste

The annual global fish production reached a record 178 million tonnes in 2020, which continues to increase. Today, 49% of the total fish is harvested from aquaculture, which is forecasted to reach 60% of the total fish produced by 2030. Considering that the wastes of fishing industries represent up to 75% of the whole organisms, the fish industry is generating a large amount of waste which is being neglected in most parts of the world. This negligence can be traced to the ridicule of the value of this resource as well as the many difficulties related to its valorisation. In addition, the massive expansion of the aquaculture industry is generating significant environmental consequences, including chemical and biological pollution, disease outbreaks that increase the fish mortality rate, unsustainable feeds, competition for coastal space, and an increase in the macroalgal blooms due to anthropogenic stressors, leading to a negative socio-economic and environmental impact. The establishment of integrated multi-trophic aquaculture (IMTA) has received increasing attention due to the environmental benefits of using waste products and transforming them into valuable products. There is a need to integrate and implement new technologies able to valorise the waste generated from the fish and aquaculture industry making the aquaculture sector and the fish industry more sustainable through the development of a circular economy scheme. This review wants to provide an overview of several approaches to valorise marine waste (e.g., dead fish, algae waste from marine and aquaculture, fish waste), by their transformation into biofuels (biomethane, biohydrogen, biodiesel, green diesel, bioethanol, or biomethanol) and recovering biomolecules such as proteins (collagen, fish hydrolysate protein), polysaccharides (chitosan, chitin, carrageenan, ulvan, alginate, fucoidan, and laminarin) and biosurfactants.

Responses of the Macroalga Ulva prolifera Müller to Ocean Acidification Revealed by Complementary NMR- and MS-Based Omics Approaches

Ocean acidification (OA) is a dramatic perturbation of seawater environments due to increasing anthropogenic emissions of CO₂. Several studies indicated that OA frequently induces marine biota stress and a reduction of biodiversity. Here, we adopted the macroalga Ulva prolifera as a model and applied a complementary multi-omics approach to investigate the metabolic profiles under normal and acidified conditions. Our results show that U. prolifera grows at higher rates in acidified environments. Consistently, we observed lower sucrose and phosphocreatine concentrations in response to a higher demand of energy for growth and a higher availability of essential amino acids, likely related to increased protein biosynthesis. In addition, pathways leading to signaling and deterrent compounds appeared perturbed. Finally, a remarkable shift was observed here for the first time in the fatty acid composition of triglycerides, with a decrease in the relative abundance of PUFAs towards an appreciable increase of palmitic acid, thus suggesting a remodeling in lipid biosynthesis. Overall, our studies revealed modulation of several biosynthetic pathways under OA conditions in which, besides the possible effects on the marine ecosystem, the metabolic changes of the alga should be taken into account considering its potential nutraceutical applications.

Fucoidan-based hydrogels particles as versatile carriers for diabetes treatment strategies

There is a current lack of fully efficient therapies for diabetes mellitus, a chronic disease where the metabolism of blood glucose is severely hindered by a deficit in insulin or cell resistance to this hormone. Therefore, it is crucial to develop new therapeutic strategies to treat this disease, including devices for the controlled delivery of insulin or encapsulation of insulin-producing cells. In this work, fucoidan (Fu) - a marine sulfated polysaccharide exhibiting relevant properties on reducing blood glucose and antioxidant and anti-inflammatory effects - was used for the development of versatile carriers envisaging diabetes advanced therapies. Fu was functionalized by methacrylation (MFu) using 8% and 12% (v/v) of methacrylic anhydride and further photocrosslinked using visible light in the presence of triethanolamine and eosin-y to produce hydrogel particles. Degree of methacrylation varied between 2.78 and 6.50, as determined by ¹HNMR, and the produced particles have an average diameter ranging from 0.63 to 1.3 mm (dry state). Insulin (5%) was added to MFu solution to produce drug-loaded particles and the release profile was assessed in phosphate buffer solution (PBS) and simulated intestinal fluid (SIF) for 24 h. Insulin was released in a sustained manner during the initial 8 h, reaching then a plateau, higher in PBS than in SIF, indicating that lower pH favors drug liberation. Moreover, the ability of MFu particles to serve as templates for the culture of human pancreatic cells was assessed using 1.1B4 cell line during up to 7 days. During the culture period studied, pancreatic beta cells were proliferating, with a global viability over 80% and tend to form pseudo-islets, thus suggesting that the proposed biomaterial could be a good candidate as versatile carrier for diabetes treatment as they sustain the release of insulin and support pancreatic beta cells viability.

Integrated biotechnology to mitigate green tides

Around the world, green tides are happening with increasing frequency because of the dual effects of increasingly intense human activity and climate change; this leads to significant impacts on marine ecology and economies. In the last decade, the world's largest green tide, which is formed by Ulva/Enteromorpha porifera, has become a recurrent phenomenon every year in the southern Yellow Sea (China), and it has been getting worse. To alleviate the impacts of such green tide outbreaks, multiple measures need to be developed. Among these approaches, biotechnology plays important roles in revealing the outbreak mechanism (e.g., molecular identification technology for algal genotypes), controlling and preventing outbreaks at the origin sites (e.g., technology to inhibit propagation), and utilizing valuable algal biomass. This review focuses on the various previously used biotechnological approaches that may be applicable to worldwide seaweed blooms that result from global climate change and environmental degradation.

Biological properties and potential of compounds extracted from red seaweeds

Macroalgae have been recently used for different applications in the food, cosmetic and pharmaceutical industry since they do not compete for land and freshwater against other resources. Moreover, they have been highlighted as a potential source of bioactive compounds. Red algae (Rhodophyta) are the largest group of seaweeds, including around 6000 different species, thus it can be hypothesized that they are a potential source of bioactive compounds. Sulfated polysaccharides, mainly agar and carrageenans, are the most relevant and exploited compounds of red algae. Other potential molecules are essential fatty acids, phycobiliproteins, vitamins, minerals, and other secondary metabolites. All these compounds have been demonstrated to exert several biological activities, among which antioxidant, anti-inflammatory, antitumor, and antimicrobial properties can be highlighted. Nevertheless, these properties need to be further tested on in vivo experiments and go in-depth in the study of the mechanism of action of the specific molecules and the understanding of the structure-activity relation. At last, the extraction technologies are essential for the correct isolation of the molecules, in a cost-effective way, to facilitate the scale-up of the processes and their further application by the industry. This manuscript is aimed at describing the fundamental composition of red algae and their most studied biological properties to pave the way to the utilization of this underused resource.

Marine origin biomaterials using a compressive and absorption methodology as cell-laden hydrogel envisaging cartilage tissue engineering

In the recent decade, marine origin products have been growingly studied as building blocks complying with the constant demand of the biomedical sector regarding the development of new devices for Tissue Engineering and Regenerative Medicine (TERM). In this work, several combinations of marine collagen-chitosan-fucoidan hydrogel were formed using a newly developed eco-friendly compressive and absorption methodology to produce hydrogels (CAMPH), which consists of compacting the biopolymers solution while removing the excess of water. The hydrogel formulations were prepared by blending solutions of 5% collagen from jellyfish and/or 3% collagen from blue shark skin, with solutions of 3% chitosan from squid pens and solutions of 10% fucoidan from brown algae, at different ratios. The biopolymer physico-chemical characterization comprised Amino Acid analysis, ATR-FTIR, CD, SDS-PAGE, ICP, XRD, and the results suggested the shark/jellyfish collagen(s) conserved the triple helical structure and had similarities with type I and type II collagen, respectively. The studied collagens also contain a denaturation temperature of around 30-32 °C and a molecular weight between 120 and 125 kDa. Additionally, the hydrogel properties were determined by rheology, water uptake ability, degradation rate, and SEM, and the results showed that all formulations had interesting mechanical (strong viscoelastic character) and structural stability properties, with a significant positive highlight in the formulation of H₃ (blending all biopolymers, i.e., 5% collagen from jellyfish, 3% collagen from skin shark, 3% chitosan and 10% of fucoidan) in the degradation test, that shows a mass loss around 18% over the 30 days, while the H₁ and H₂, present a mass loss of around 35% and 44%, respectively. Additionally, the in vitro cellular assessments using chondrocyte cells (ATDC5) in encapsulated state revealed, for all hydrogel formulations, a non-cytotoxic behavior. Furthermore, Live/Dead assay and Phalloidin/DAPI staining, to assess the cytoskeletal organization, proved that the hydrogels can provide a suitable microenvironment for cell adhesion, viability, and proliferation, after being encapsulated. Overall, the results show that all marine collagen (jellyfish/shark)-chitosan-fucoidan hydrogel formulations provide a good structural architecture and microenvironment, highlighting the H₃ biomaterial due to containing more polymers in their composition, making it suitable for biomedical articular cartilage therapies.

Characteristics of Marine Biomaterials and Their Applications in Biomedicine

Oceans have vast potential to develop high-value bioactive substances and biomaterials. In the past decades, many biomaterials have come from marine organisms, but due to the wide variety of organisms living in the oceans, the great diversity of marine-derived materials remains explored. The marine biomaterials that have been found and studied have excellent biological activity, unique chemical structure, good biocompatibility, low toxicity, and suitable degradation, and can be used as attractive tissue material engineering and regenerative medicine applications. In this review, we give an overview of the extraction and processing methods and chemical and biological characteristics of common marine polysaccharides and proteins. This review also briefly explains their important applications in anticancer, antiviral, drug delivery, tissue engineering, and other fields.

Marine Polysaccharides in Tailor- Made Drug Delivery

Abstract:

Marine sources have attracted much interest as an emerging source of biomaterials in drug delivery applications. Amongst all other marine biopolymers, polysaccharides have been the mostly investigated class of biomaterials. The low cytotoxic behavior, in combination with the newly explored health benefits of marine polysaccharides has made it one of the prime research areas in the pharmaceutical and biomedical fields. In this review, we focused on all available marine polysaccharides, including their classification based on biological sources. The applications of several marine polysaccharides in recent years for tissue-specific novel drug delivery including gastrointestinal, brain tissue, transdermal, ocular, liver, and lung have also been discussed here. The abundant availability in nature, cost-effective extraction, and purification process along with a favorable biodegradable profile will encourage researchers to continue investigating marine polysaccharides for exploring newer applications in targeting specific delivery of therapeutics.

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.

Osmundea sp. macroalgal polysaccharide-based nanoparticles produced by flash nanocomplexation technique

The macroalgae-derived polysaccharides' biological potential has been explored due to their attractive intrinsic properties such as biocompatibility, biodegradability, and their ability to conjugate with other compounds. In particular, in the drug delivery systems field, the anionic macroalgae polysaccharides have been combined with cationic compounds through ionotropic gelation and/or bulk mixing. However, these techniques did not assure reproducibility, and the stability of nanoparticles is undesired. To overcome these limitations, herein, the polysaccharide extracted from Osmundea sp. was used to produce nanoparticles through the flash nanocomplexation technique. This approach rapidly mixed the negative charge of macroalgae polysaccharide with a positive chitosan charge on a millisecond timescale. Further, diclofenac (an anti-inflammatory drug) was also incorporated into complex nanoparticles. Overall, the gathered data showed that hydrodynamic diameter nanoparticles values lower than 100 nm, presenting a narrow size distribution and stability. Also, the diclofenac exhibited a targeted and sustained release profile in simulating inflammatory conditions. Likewise, the nanoparticles showed excellent biological properties, evidencing their suitability to be used to treat inflammatory skin diseases.

Bioactive Carbohydrate Polymers-Between Myth and Reality

Polysaccharides are complex macromolecules long regarded as energetic storage resources or as components of plant and fungal cell walls. They have also been described as plant mucilages or microbial exopolysaccharides. The development of glycosciences has led to a partial and difficult deciphering of their other biological functions in living organisms. The objectives of glycobiochemistry and glycobiology are currently to correlate some structural features of polysaccharides with some biological responses in the producing organisms or in another one. In this context, the literature focusing on bioactive polysaccharides has increased exponentially during the last two decades, being sometimes very optimistic for some new applications of bioactive polysaccharides, notably in the medical field. Therefore, this review aims to examine bioactive polysaccharide, taking a critical look of the different biological activities reported by authors and the reality of the market. It focuses also on the chemical, biochemical, enzymatic, and physical modifications of these biopolymers to optimize their potential as bioactive agents.

Marine origin materials on biomaterials and advanced therapies to cartilage tissue engineering and regenerative medicine

The body's self-repair capacity is limited, including injuries on articular cartilage zones. Over the past few decades, tissue engineering and regenerative medicine (TERM) has focused its studies on the development of natural biomaterials for clinical applications aiming to overcome this self-therapeutic bottleneck. This review focuses on the development of these biomaterials using compounds and materials from marine sources that are able to be produced in a sustainable way, as an alternative to mammal sources (e.g., collagens) and benefiting from their biological properties, such as biocompatibility, low antigenicity, biodegradability, among others. The structure and composition of the new biomaterials require mimicking the native extracellular matrix (ECM) of articular cartilage tissue. To design an ideal temporary tissue-scaffold, it needs to provide a suitable environment for cell growth (cell attachment, proliferation, and differentiation), towards the regeneration of the damaged tissues. Overall, the purpose of this review is to summarize various marine sources to be used in the development of different tissue-scaffolds with the capability to sustain cells envisaging cartilage tissue engineering, analysing the systems displaying more promising performance, while pointing out current limitations and steps to be given in the near future.

Influence of molecular weight fractionation on the antimicrobial and anticancer properties of a fucoidan rich-extract from the macroalgae Fucus vesiculosus

The objective of this study was to investigate the antimicrobial and anticancer properties of a fucoidan extract and subsequent fractions isolated from the macroalgae Fucus vesiculosus. The fractions obtained (>300 kDa, <300 kDa, <100 kDa, <50 kDa and <10 kDa) could inhibit the growth of B. subtilis, E. coli, L. innocua and P. fluorescens when assayed at concentrations between 12,500 and 25,000 ppm. The bacterial growth was monitored by optical density (OD) measurements (600 nm, 24 h) at 30 °C or 37 °C, depending upon on the strain used. The extracted fractions were also tested for cytotoxicity against brain glioblastoma cancer cells using the Alamar Blue assay for 24 h, 48 h and 6 days. The >300 kDa fraction presented the lowest IC50 values (0.052% - 24 h; 0.032% - 6 days). The potential bioactivity of fucoidan as an antimicrobial and anticancer agent was demonstrated in this study. Hence, the related mechanisms of action should be explored in a near future.

Rediscovering bacterial exopolysaccharides of terrestrial and marine origins: novel insights on their distribution, biosynthesis, biotechnological production, and future perspectives

Bacteria exist in colonies as aggregates or associated with surfaces forming biofilms rather than planktonic cells. Living in such a unique manner is always mediated via a matrix of extracellular polymeric substances, which are composed mainly of polysaccharides or specifically exopolysaccharides (EPS). Biofilm formation and hence EPS production are affected by biotic and abiotic factors inducing/inhibiting several involved genes and other molecules. In addition, various aspects of bacterial EPS regarding: physiological functions, molecular weight, and chemical composition were demonstrated. Recent investigations have revealed a wide spectrum of EPS chemical and physicochemical properties showing promising applications in different industrial sectors. For instance, lactic acid bacteria (LAB)- and marine-derived EPS exhibit: immunomodulatory, antioxidant, antitumor, bioremediation of heavy metals, as well as thickening and viscosity modifiers in the food industry. However, bacterial EPS have not yet been commercially implemented, in contrast to plant-derived analogues. The current review aims to rediscover the EPS structural and biosynthetic features derived from marine and terrestrial bacteria, and applications as well.

Molecular Mechanisms Underlying the Anti-Breast Cancer Stem Cell Activity of Pterocladia capillacea and Corallina officinalis Polysaccharides

OBJECTIVE

This study aimed to appraise the activity of Pterocladia capillacea and Corallina officinalis polysaccharides against breast cancer stem cells (BCSCs). P. capillacea and C. officinalis polysaccharides were characterized to be sulfated polysaccharide-protein complexes.

METHODS

Cytotoxicity of the polysaccharides against MDA-MB-231 and MCF-7 cell lines along with their impact on CD44+/CD24- and aldehyde dehydrogenase 1(ALDH1) positive BCSC population were determined. Their effect on gene expression of CSC markers, Wnt/β-catenin and Notch signaling pathways was evaluated.

RESULTS

P. capillacea and C. officinalis polysaccharides inhibited the growth of breast cancer cells and reduced BCSC subpopulation. P. capillacea polysaccharides significantly down-regulated OCT4, SOX2, ALDH1A3 and vimentin in MDA-MB-231 as well as in MCF-7 cells except for vimentin that was up-regulated in MCF-7 cells. C. officinalis polysaccharides exhibited similar effects except for OCT4 that was up-regulated in MDA-MB-231 cells. Significant suppression of Cyclin D1 gene expression was noted in MDA-MB-231 and MCF-7 cells treated with P. capillacea or C. officinalis polysaccharides. β-catenin and c-Myc genes were significantly down-regulated in MDA-MB-231 cells treated with C. officinalis and P. capillacea polysaccharides, respectively, while being up-regulated in MCF-7 cells treated with either of them. Additionally, P. capillacea and C. officinalis polysaccharides significantly down-regulated Hes1 gene in MCF-7 cells despite increasing Notch1 gene expression level. However, significant down-regulation of Notch1 gene was observed in MDA-MB-231 cells treated with P. capillacea polysaccharides.

CONCLUSION

Collectively, this study provides evidence for the effectiveness of P. capillacea and C. officinalis polysaccharides in targeting BCSCs through interfering with substantial signaling pathways contributing to their functionality.

Red Seaweeds as a Source of Nutrients and Bioactive Compounds: Optimization of the Extraction

The present work aimed to determine the nutritional composition (ash, protein, fat, carbohydrate content and energy value), phenolic compounds, pigments and organic acids content of three typical red algae from the Northwest of Spain: Chondrus crispus, Mastocarpus stellatus, and Gigartina pistillata; as well as their antioxidant and antimicrobial activities. Furthermore, the present work compared two extraction techniques: conventional heat assisted extraction (HAE) and high pressure assisted extraction (HPAE) to maximize the yield and the concentration of target compounds. Different independent variables were considered for the response study. Time (t) and percentage of ethanol of the solvent (S) were chosen for both techniques and temperature (T) and pressure (P) were used for HAE and HPAE, respectively. The experiments were designed following a response surface methodology (RSM) approach. The obtained results showed a similar nutritional composition between algae samples: low-fat content and high content of proteins, carbohydrates and energy. All tested algae showed good antioxidant and antimicrobial properties. Finally, HEA demonstrated to be the most efficient extraction technique. This study confirms the potential of red algae to be part of the human diet as a source of non-animal protein, due to its nutritional content, phenolic profile, pigments concentration and bioactive properties, which proves that HAE is the optimum technique for the extraction maximization.

Recent trends in natural polysaccharide based bioinks for multiscale 3D printing in tissue regeneration: A review

Biofabrication by three-dimensional (3D) printing has been an attractive technology in harnessing the possibility to print anatomical shaped native tissues with controlled architecture and resolution. 3D printing offers the possibility to reproduce complex microarchitecture of native tissues by printing live cells in a layer by layer deposition to provide a biomimetic structural environment for tissue formation and host tissue integration. Plant based biomaterials derived from green and sustainable sources have represented to emulate native physicochemical and biological cues in order to direct specific cellular response and formation of new tissues through biomolecular recognition patterns. This comprehensive review aims to analyze and identify the most commonly used plant based bioinks for 3D printing applications. An overview on the role of different plant based biomaterial of terrestrial origin (Starch, Nanocellulose and Pectin) and marine origin (Ulvan, Alginate, Fucoidan, Agarose and Carrageenan) used for 3D printing applications are discussed elaborately. Furthermore, this review will also emphasis in the functional aspects of different 3D printers, appropriate printing material, merits and demerits of numerous plant based bioinks in developing 3D printed tissue-like constructs. Additionally, the underlying potential benefits, limitations and future perspectives of plant based bioinks for tissue engineering (TE) applications are also discussed.

Wound Dressing Hydrogel of Enteromorpha prolifera Polysaccharide-Polyacrylamide Composite: A Facile Transformation of Marine Blooming into Biomedical Material

Great endeavors have been dedicated to the development of wound dressing materials. However, there is still a demand for developing a wound dressing hydrogel that integrates natural macromolecules without requiring extra chemical modifications, so as to enable a facile transformation and practical application in wound healing. Herein, a composite hydrogel was prepared with water-soluble polysaccharides from Enteromorpha prolifera (PEP) cross-linked with boric acid and polyacrylamide cross-linked via polymerization (PAM) using a one-pot method. The dual-network of this hydrogel enabled it to have an ultratough mechanical strength. Moreover, interfacial characterizations reflected that the hydrogen bonds and dynamic hydroxyl-borate bonds contributed to the self-healing ability of the PEP-PAM hydrogel, and the surface groups on the hydrogel allowed for tissue adhesiveness and natural antioxidant properties. Additionally, human epidermal growth factor-loaded PEP-PAM hydrogel promoted cell proliferation and migration in vitro and significantly accelerated wound healing in vivo on model rats. These progresses suggested a prospect for the PEP-PAM hydrogel as an effective and easily available wound dressing material. Remarkably, this work showcases that a wound dressing hydrogel can be facially developed by using natural polysaccharides as a one component and offers a new route for the high-value utilization of disastrous marine blooming biomass by transforming it into a biomedical material.

Antioxidative study of polysaccharides extracted from red (Kappaphycus alvarezii), green (Kappaphycus striatus) and brown (Padina gymnospora) marine macroalgae/seaweed

Sterile and fresh tissues of three marine macroalgae red, green and brown (Kappaphycus alvarezii, Kappaphycus striatus and Padina gymnospora) collected from Malaysia east costal seas were compared for the antioxidants and polysaccharide composition of sugars as well as the active components. Results obtained showed that polysaccharides isolated from Kappaphycus alvarezii, Kappaphycus striatus and Padina gymnospora) can be used as a source of natural antioxidant compounds as they possess antioxidant potential in which the Padina gymnospora showed 15.56 ± 0.12 mg/mL to be the best antioxidants among all the polysaccharides studied. The hot water extraction method is effective in isolating polysaccharides from studied seaweeds. The GC–MS analysis revealed that there is presence of chemical compounds such as furfural was 25.53% in Kappaphycus alvarezii and 21.04% in Kappaphycus striatus also Padina gymnospora incorporates n- Hexadecanoic acid about 26.31% in seaweed polysaccharides that contribute to their antioxidant activities. Further studies can be done on determining the seaweed species that are available abundantly with the best source of natural antioxidant compounds.

Poly(δ-valerolactone)/Poly(ethylene-co-vinylalcohol)/β-Tri-calcium Phosphate Composite as Scaffolds: Preparation, Properties, and In Vitro Amoxicillin Release

Two poly(δ-valerolactone)/poly(ethylene-co-vinylalcohol)/beta-tricalcium phosphate (PEVAL/PDVAL/β-TCP) composites containing an equal ratio of polymer and filled with 50 and 70 wt% of β-TCP microparticles were prepared by the solvent casting method. Interconnected pores were realized using the salt leached technique, and the porosity of the resulted composites was evaluated by the scanning electron microscopy (SEM) method. The homogeneity of the hybrid materials was investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The prepared materials' SEM images showed interconnected micropores that respond to the conditions required to allow their uses as scaffolds. The porosity of each scaffold was determined from micro computed tomography (micro-CT) data, and the analysis of the mechanical properties of the prepared materials was studied through the stress-strain compressive test. The proliferation test results used human mesenchymal stem cells (MSCs) to grow and proliferate on the different types of prepared materials, reflecting that the hybrid materials were non-toxic and could be biologically acceptable scaffolds. The antibacterial activity test revealed that incorporation of amoxicillin in the specimens could inhibit the bacterial growth of S. aureus. The in vitro study of the release of amoxicillin from the PEVAL/PDVAL/amoxicillin and PEVAL/PDVAL/β-TCP/amoxicillin drug carrier systems in pH media 7.4, during eight days, gave promising results, and the antibiotic diffusion in these scaffolds obeys the Fickian model.

Silk fibroin nanofibers enhance cell adhesion of blood-derived fibroblast-like cells: A potential application for wound healing

AIM:

The aim of this study is to evaluate silk-fibroin electrospun nanofibers and blood-derived fibroblast-like cells for cytotoxicity and cell adhesion.

BACKGROUND:

Silk fibroin (SF) has emerged as a favorable and potential bio-material owing to its unique properties such as biocompatibility, biodegradability, the possibility of functional modifications, mechanical strength, and regenerative capability. Despite current advancements in tissue engineering technologies, delay wound healing and scar formation remain unresolved. Bioequivalent skin graft having human fibroblast and keratinocytes (Apligraft^®) has proven to be beneficial, but the cost is a limiting factor.

OBJECTIVE:

The blood born fibroblast-like cells express several growth factors, extracellular matrix proteins, and these factors are crucial in the various steps of the wound-healing process. SF is an idea polymer by the virtue of its multifaceted characteristics such as mechanical strength, biodegradability, improved cell attachment, biocompatibility, good elasticity, having application in biomedical, tissue engineering, and medicine. The objective of the present study is to evaluate SF as a biomaterial for making nanofibers scaffold and culturing blood-derived fibroblast-like cells on it for the potential application to wound site.

MATERIALS AND METHODS:

Blood-derived fibroblast-like cells evaluated for cytotoxicity, collagen 1 expression, and cell adhesion on SF electrospun nanofibers. The silk nanofibers were fabricated by the electrospinning method using silk-derived fibroin solution and analyzed for protein composition, viscosity, and further characterized using the Fourier transformed infrared spectroscopy.

RESULTS:

The SF nanofibers were nontoxic to the blood-derived fibroblast-like cells. It improved cell adhesion with collagen 1 expression.

CONCLUSION:

The composite scaffold of SF nanofibers with blood-derived fibroblast-like cells would be a potential healing patch for many types of wounds.

Bottom-Up Self-assembled Hydrogel-Mineral Composites Regenerate Rabbit Ulna Defect without Added Growth Factors

Hydrogel-based biomaterials have advanced bone tissue engineering approaches in the last decade, through their ability to serve as a carrier for potent growth factor, bone morphogenic protein-2 (BMP-2). However, biophysical properties of hydrogels such as multiscale structural hierarchy and bone extracellular matrix (ECM)-mimetic microarchitecture are underutilized while designing current bone grafts. Incorporation of these properties offers great potential to create a favorable biomimetic microenvironment to harness their regenerative potential. Here, we present our approach to fabricate collagen-inspired bioactive hydrogel scaffolds (referred to as "RegenMatrix") to guide and enhance bone regeneration in a rabbit ulna defect model through the mimicry of multiscale architecture of bone ECM, i.e., native collagen. Specifically, we employed polyelectrolyte complexation to promote bottom-up self-assembly of oppositely charged polysaccharides (chitosan and kappa-carrageenan) at multiple length scales forming fibrils, which further assemble into fibers. The self-assembly and bioinspired scaffold fabrication method resulted in robust cylindrical RegenMatrix with excellent retention of the multiscale architecture and uniform mineral deposition throughout the scaffolds. RegenMatrix, in both nonmineralized and mineralized forms, enhanced bone regeneration in the semiload-bearing ulna defect when compared to the empty defect. RegenMatrix also showed greater histocompatibility without any fibrous tissue formation. Collectively, the RegenMatrix developed in this study has a great potential as a bioactive bone graft without any added growth factors.

Microspheres containing biosynthesized silver nanoparticles with alginate-nano hydroxyapatite for biomedical applications

Scaffolding system plays an important role in the development of artificial bone for treatment of defective or diseased bone tissue. In the present work, we have developed microspheres (COS-Ag-Alg-HA) containing chitooligosaccharide (COS) coated silver nanoparticles (Ag NPs) with alginate (Alg) and hydroxyapatite (HA) as bone graft substitutes. The developed microspheres were characterized through various analytical techniques such as UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, field emission scanning electron microscopy with EDX and evaluated the mechanical strength by using universal testing machine. In addition to this, antimicrobial activity and biocompatibility of the developed microspheres were evaluated with pathogenic microbes and osteoblast-like cells, respectively. Results suggest that microspheres are rigid, and strong chemical interactions were observed between the materials. The size of the microspheres was ranging from 1.5 ± 0.5 to 4.0 ± 0.5 mm. Significant microbial inhibition was observed against Staphylococcus aureus, and the developed microspheres are biocompatible with osteoblast-like cells. Based on the aforementioned finding results, the developed microsphere is proposed to be a potential candidate for bone tissue repair and regeneration.

Seaweed polysaccharides as macromolecular crowding agents

Development of mesenchymal stem cell-based tissue engineered implantable devices requires prolonged in vitro culture for the development of a three-dimensional implantable device, which leads to phenotypic drift, thus hindering the clinical translation and commercialisation of such approaches. Macromolecular crowding, a biophysical phenomenon based on the principles of excluded-volume effect, dramatically accelerates and increases extracellular matrix deposition during in vitro culture. However, the optimal macromolecular crowder is still elusive. Herein, we evaluated the biophysical properties of various concentrations of different seaweed in origin sulphated polysaccharides and their effect on human adipose derived stem cell cultures. Carrageenan, possibly due to its high sulphation degree, exhibited the highest negative charge values. No correlation was observed between the different concentrations of the crowders and charge, polydispersity index, hydrodynamic radius and fraction volume occupancy across all crowders. None of the crowders, but arabinogalactan, negatively affected cell viability. Carrageenan, fucoidan, galactofucan and ulvan increased extracellular matrix (especially collagen type I and collagen type V) deposition. Carrageenan induced the highest osteogenic effect and galactofucan and fucoidan demonstrated the highest chondrogenic effect. All crowders were relatively ineffective with respect to adipogenesis. Our data highlight the potential of sulphated seaweed polysaccharides for tissue engineering purposes.

A review on fucoidan antitumor strategies: From a biological active agent to a structural component of fucoidan-based systems

Due to the severe side-effects and the toxicity to healthy tissues, cancer treatments based in chemotherapy have not fully achieved the desire outcomes so far. The use of natural compound may be of great value to develop better tolerated therapies. Fucoidan is a marine sulfated polysaccharide extracted from brown algae that, besides other biological activities, has been reported to present interesting anti-cancer potential. This review briefly introduces fucoidan chemical structure, physicochemical properties and the above-mentioned biological feature. Fucoidan usage as soluble agent presents promising results herein described for different types of cancer. Trying to enhance and optimize fucoidan usage in the cancer field, different systems, namely drug delivery, have been recently developed to target different types of cancers. This aspect will be presented in detail, highlighting the role of fucoidan on their reported or envisaged performance.

Bioactive and thermostable sulphated polysaccharide from Sargassum swartzii with drug delivery applications

Sulphated Polysaccharides (SP) were extracted from a brown seaweed Sargassum swartzii by two extraction methods using hydrochloric acid and hot water. The sulphated polysaccharide yield using the hot water extraction method was found to be higher and hence used for further study. The extracted polysaccharide was characterized using UV, FT-IR, biochemical and thin layer chromatography analyses. Further, the purity of the extracted polysaccharide was ascertained by HPLC analysis. The sugars present in the sulphated polysaccharide were revealed by acid hydrolysis. The structure of the extracted SP was revealed as fucoidan using the NMR spectrum. Thermal stability of the sulphated polysaccharide was assessed using Thermogravimetric analysis and polymer was found to be stable up to 700 °C. Anti-oxidant and anti-inflammatory activities were evaluated using phosphomolybdenum and BSA assay, respectively. Cell proliferation analysis using MTT assay against normal cell lines revealed that the polysaccharide is biocompatible while with cancer cell lines, the compound exhibited potential anti-proliferative activity. Application of this sulphated polysaccharide as a carrier for drug delivery with rutin as a model drug was explored. The drug release kinetics was modeled and the stability of the rutin encapsulated SP nano formulation was studied.

Study on physicochemical properties and antioxidant activity of polysaccharides from Desmodesmus armatus

Physicochemical properties and antioxidant activities of Desmodesmus armatus polysaccharides (DAP) were studied. They were extracted by microwave-assisted constant temperature extraction and purification by DEAE-cellulose 52. Four eluents of water (DAP1), 0.25 mol/L NaCl (DAP2), 0.5 mol/L NaCl (DAP3), and 1.0 mol/L NaCl (DAP4) were collected. Four polysaccharides fractions were analyzed, and they were all composed of mannose, rhamnose, glucuronic acid, galacturonic acid, arabinose, and fucose. Gel Permeation Chromatography (GPC) analysis showed that the four polysaccharides fractions have a uniform molecular weight distribution. Scanning electron microscope showed that DAP1 had a dense structure and a smooth but uneven surface, while DAP2, DAP3, and DAP4 were amorphous solids in sheets. Oxidation in vitro experiments showed that DAP2 and DAP3 had scavenging effects on ABTS, DPPH, and hydroxyl radicals. PRACTICAL APPLICATIONS: In the determination of the antioxidant activity, it was found that the antioxidative activity of the polysaccharide of Desmodesmus armatus measured was significantly stronger than the crude polysaccharide of other microalgae. After the polysaccharide was purified, two polysaccharide fractions (DAP2 and DAP3) of Desmodesmus armatus were found to have strong scavenging ability to ABTS, DPPH, and hydroxyl radicals. They can be regarded as a new type of antioxidant, and the differences in the physicochemical properties between the parts can provide a preliminary explanation for the differences in antioxidant activity. But the connection between them needs further analysis. The Desmodesmus armatus used in the experiment is easy to cultivate and easy to obtain, which greatly increases its applicability. This research opens up new possibilities for the development of antioxidants and provides favorable evidence for the use of Desmodesmus armatus in food and feed.

Marine-Derived Polymeric Materials and Biomimetics: An Overview

The review covers recent literature on the ocean as both a source of biotechnological tools and as a source of bio-inspired materials. The emphasis is on marine biomacromolecules namely hyaluronic acid, chitin and chitosan, peptides, collagen, enzymes, polysaccharides from algae, and secondary metabolites like mycosporines. Their specific biological, physicochemical and structural properties together with relevant applications in biocomposite materials have been included. Additionally, it refers to the marine organisms as source of inspiration for the design and development of sustainable and functional (bio)materials. Marine biological functions that mimic reef fish mucus, marine adhesives and structural colouration are explained.

Hybrid Sponge-Like Scaffolds Based on Ulvan and Gelatin: Design, Characterization and Evaluation of Their Potential Use in Bone Tissue Engineering

Ulvan, a bioactive natural sulfated polysaccharide, and gelatin, a collagen-derived biopolymer, have attracted interest for the preparation of biomaterials for different biomedical applications, due to their demonstrated compatibility for cell attachment and proliferation. Both ulvan and gelatin have exhibited osteoinductive potential, either alone or in combination with other materials. In the current work, a series of novel hybrid scaffolds based on crosslinked ulvan and gelatin was designed, prepared and characterized. Their mechanical performance, thermal stability, porosity, water-uptake and in vitro degradation ability were assessed, while their morphology was analyzed through scanning electron microscopy. The prepared hybrid ulvan/gelatin scaffolds were characterized by a highly porous and interconnected structure. Human adipose-derived mesenchymal stem cells (hADMSCs) were seeded in selected ulvan/gelatin hybrid scaffolds and their adhesion, survival, proliferation, and osteogenic differentiation efficiency was evaluated. Overall, it was found that the prepared hybrid sponge-like scaffolds could efficiently support mesenchymal stem cells' adhesion and proliferation, suggesting that such scaffolds could have potential uses in bone tissue engineering.

Carrageenan: A Wonder Polymer from Marine Algae for Potential Drug Delivery Applications

BACKGROUND

With the advancement in the field of medical science, the idea of sustained release of the therapeutic agents in the patient's body has remained a major thrust for developing advanced drug delivery systems (DDSs). The critical requirement for fabricating these DDSs is to facilitate the delivery of their cargos in a spatio-temporal and pharmacokinetically-controlled manner. Albeit the synthetic polymer-based DDSs normally address the above-mentioned conditions, their potential cytotoxicity and high cost have ultimately constrained their success. Consequently, the utilization of natural polymers for the fabrication of tunable DDSs owing to their biocompatible, biodegradable, and non-toxic nature can be regarded as a significant stride in the field of drug delivery. Marine environment serves as an untapped resource of varied range of materials such as polysaccharides, which can easily be utilized for developing various DDSs.

METHODS

Carrageenans are the sulfated polysaccharides that are extracted from the cell wall of red seaweeds. They exhibit an assimilation of various biological activities such as anti-thrombotic, anti-viral, anticancer, and immunomodulatory properties. The main aim of the presented review is threefold. The first one is to describe the unique physicochemical properties and structural composition of different types of carrageenans. The second is to illustrate the preparation methods of the different carrageenan-based macro- and micro-dimensional DDSs like hydrogels, microparticles, and microspheres respectively. Fabrication techniques of some advanced DDSs such as floating hydrogels, aerogels, and 3-D printed hydrogels have also been discussed in this review. Next, considerable attention has been paid to list down the recent applications of carrageenan-based polymeric architectures in the field of drug delivery.

RESULTS

Presence of structural variations among the different carrageenan types helps in regulating their temperature and ion-dependent sol-to-gel transition behavior. The constraint of low mechanical strength of reversible gels can be easily eradicated using chemical crosslinking techniques. Carrageenan based-microdimesional DDSs (e.g. microspheres, microparticles) can be utilized for easy and controlled drug administration. Moreover, carrageenans can be fabricated as 3-D printed hydrogels, floating hydrogels, and aerogels for controlled drug delivery applications.

CONCLUSION

In order to address the problems associated with many of the available DDSs, carrageenans are establishing their worth recently as potential drug carriers owing to their varied range of properties. Different architectures of carrageenans are currently being explored as advanced DDSs. In the near future, translation of carrageenan-based advanced DDSs in the clinical applications seems inevitable.

Natural Products and Their Bioactive Compounds: Neuroprotective Potentials against Neurodegenerative Diseases

In recent years, natural products, which originate from plants, animals, and fungi, together with their bioactive compounds have been intensively explored and studied for their therapeutic potentials for various diseases such as cardiovascular, diabetes, hypertension, reproductive, cancer, and neurodegenerative diseases. Neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis are characterized by the progressive dysfunction and loss of neuronal structure and function that resulted in the neuronal cell death. Since the multifactorial pathological mechanisms are associated with neurodegeneration, targeting multiple mechanisms of actions and neuroprotection approach, which involves preventing cell death and restoring the function to damaged neurons, could be promising strategies for the prevention and therapeutic of neurodegenerative diseases. Natural products have emerged as potential neuroprotective agents for the treatment of neurodegenerative diseases. This review focused on the therapeutic potential of natural products and their bioactive compounds to exert a neuroprotective effect on the pathologies of neurodegenerative diseases.

The Potential of Fucose-Containing Sulfated Polysaccharides As Scaffolds for Biomedical Applications

Marine environments have a high quantity and diversity of sulfated polysaccharides. In coastal regions brown algae are the most abundant biomass producers and their cell walls have fucosecontaining sulfated polysaccharides (FCSP), known as fucans and/or fucoidans. These sulfated compounds have been widely researched for their biomedical properties, namely the immunomodulatory, haemostasis, pathogen inhibition, anti-inflammatory capacity, and antitumoral. These activities are probably due to their ability to mimic the carbohydrate moieties of mammalian glycosaminoglycans. Therefore, the FCSP are interesting compounds for application in health-related subjects, mainly for developing scaffolds for delivery systems or tissue regeneration. FCSP showed potential for these applications also due to their ability to form stable 3D structures with other polymers able to entrap therapeutic agents or cell and growth factors, besides their biocompatibility and biodegradability. However, for the clinical use of these biopolymers well-defined reproducible molecules are required in order to accurately establish relationships between structural features and human health applications.

Mucoadhesive properties of sulphated polysaccharides carrageenans from red seaweed families Gigartinaceae and Tichocarpaceae

The mucoadhesive properties of different types of carrageenan (kappa-, kappa/beta-, iota/kappa- and lambda-CRGs) isolated from red seaweed families Gigartinaceae and Tichocarpaceae collected on the Pacific coast were studied. We examined the interaction between CRGs and pig stomach mucin in dilute aqueous solutions using a set of methods. Measurements of the dynamic light scattering of mucin in the presence of CRG showed that the polysaccharides cause aggregation of mucin particles, as confirmed by microscopy data. The addition of CRGs to solutions of mucin resulted in the formation of a mixture that changed the charge of mucin, especially in the case of kappa- and kappa/beta-CRGs. The interaction between CRG and porcine gastric mucin in the presence of various additives confirmed that hydrogen bonds and electrostatic interactions are complemented when CRG and mucin are mixed in an aqueous medium, which is also confirmed by in vitro methods based on measurements of work of adhesion and shear stress. Kappa- and kappa/beta-CRGs that contain 3,6-anhydro-α-d-galactopyranose chains (DA) have high molecular weight and exhibit a high density of available hydrogen bonding groups able to interact more strongly with mucin glycoproteins.