Bioactive potentials of sulfated polysaccharides isolated from brown seaweed Sargassum spp in related to human health applications: A review

F2-sulfated polysaccharides of Laetiporus sulphureus suppress triple-negative breast cancer cell proliferation and metastasis through the EGFR-mediated signaling pathway

Sulfated polysaccharides (SPS) are a unique secondary metabolite isolated from Laetiporus sulphureus. This study examined the detailed molecular mechanisms of action of F2, a medium molecular weight SPS of L. sulphureus, on breast cancer MDA-MB-231 cell proliferation and metastasis. Results showed that the sulfate and protein content of F2 were 2.1 % and 15.6 %, respectively. F2 had a molecular weight of 23.8 kDa and did not contain a triple helix conformation. The monosaccharide composition of F2 was mannose, galactose, glucose, and fucose. F2 inhibited MDA-MB-231 cell proliferation mainly by blocking the cell cycle at the G0/G1 phase, which was attributed to the down-regulation of CDK4 and cyclin D1 and the up-regulation of p21 protein expression. F2 suppressed epidermal growth factor receptor (EGFR)-mediated intracellular signaling events, such as phosphorylation of ERK1/2, Akt, and GSK-3β and activation of NF-κB and β-catenin, resulting in the cell cycle arrest. Moreover, F2 significantly reduced the EGFR phosphorylation and expression, and the level of mutant p53 protein. F2 also effectively inhibited breast cancer cell migration and invasion through down-regulating MMP-9 and MMP-2 protein expression. In conclusion, this study demonstrated that F2 exhibited anti-proliferative and anti-metastatic activities against MDA-MB-231 cells by inhibiting the activation of EGFR-mediated signaling pathways.

Structural characterization of an acidic polysaccharide from scagassum and its effect on shelf life of golden pompano fillets during cold storage

This study investigated the structural characteristics of an acidic polysaccharide (SCP-B) isolated from scagassum and the use of SCP-B coatings to enhance the quality and shelf life of golden pompano fillets. The results indicated that the main glucoside bond structure of SCP-B was →3)-α-Fucp-(1 → 4)-β-ManA-(1 → 3)-α-GulA-(1→, whereas the terminal residues of β-ManA-(1 → and α-Fucp-(1 → linked to O-2 of →2,3)-β-Fucp-(1→, and α-GulA-(1 → linked to O-2 of →2,3)-α-GulA-(1→. When the SCP-B concentration reached 3.13 μg/mL, it exerted a significant antimicrobial effect against Shewanella putrefaciens. This study demonstrated that SCP-B prolonged the shelf life of golden pompano fillets (≥2 d) by inhibiting the proliferation of microorganisms. Furthermore, SCP-B substantially inhibited discoloration, texture deterioration, and water loss, which displayed a concentration dependence. The SCP-B with antimicrobial activity could effectively extend the shelf life of cold stored fillets, which broadens the application of scagassum polysaccharide in the field of aquatic products.

Green synthesis of Ag/V2O5 and Ag/V2O5-curdlan nanocomposites from Sargassum latifolium extract for enhanced antimicrobial and antioxidant activities

The emergence of clinic-isolated bacteria and their ability to develop resistance mechanisms against conventional antimicrobials highlights the urgent need for novel, sustainable antimicrobial agents. This study explores the synthesis of Ag/V2O5 nanocomposites (NCs) using Sargassum latifolium extract, which is incorporated into a curdlan biocompatible matrix. The developed nanocomposites are evaluated for their antioxidant and antimicrobial activities, with a particular focus on their effectiveness against pathogenic bacteria. The applied method in this work combines green synthesis with the process of uniform distribution of nanoparticles to a biocompatible polymer, which is a way forward towards the design of efficient biocompatible antimicrobial systems. The Ag/V2O5 nanoparticles prepared with green synthesis were characterized by UV-Vis absorption, FTIR, XRD, SEM, EDX, zeta potential, DLS, and TEM. It has also been established that the antimicrobial property of the curdlan matrix has been enhanced with the addition of Ag/V2O5 nanoparticles in the incorporated curdlan composites. Ag/V2O5-curdlan also showed significantly enhanced antimicrobial activity against Gram-negative bacteria and Gram-positive bacteria thus implying enhanced antimicrobial action of the prepared nanocomposite by increasing the size of the bacterial zone of inhibition from 14.0 to 18.0 mm. Besides, the curdlan NC in the presence of Ag/V2O5 demonstrated an even lower value of MIC against Rhizoctonia solani (140.156 μg/mL) in comparison with Ag/V2O5 NC (226.413 μg/mL) thus predicting Augmented antifungal activity. Through performing TEM analysis, we have observed significant morphological changes in R. solani strain when the Ag/V2O5-curdlan NC was used. However, the Ag/V2O5-curdlan NC had a notably high antioxidant activity with IC50 of 0.302 mg/mL to DPPH radical scavenging assay. These results reaffirm the enhancement in antimicrobial properties when Ag/V2O5 and curdlan work together and agree with the objective of this work to propose novel and worthwhile nanomaterials for potentially applicable areas like food packaging or agriculture with insignificant harm to the environment.

Structural characterization of a sulfated polysaccharide from Gracilariadomingensis and potential anti-inflammatory and antinociceptive effects

Seaweeds are natural sources of sulfated polysaccharides (SPs), biopolymers with remarkable pharmacological properties, including biological actions capable of attenuating components of the inflammatory process such as edema, cytokines, cell migration and pain. Our results confirm that SPs obtained from Gracilaria domingensis (SP-GD) are agarans, primarily composed of residues of β-d-galactopyranose 6-sulfate and 3,6-anhydro-α-l-galactopyranose. Specifically, SP-GD at a dose of 10 mg/kg was effective in significantly reducing paw edema induced by carrageenan or histamine, serotonin, bradykinin, 48/80 and prostaglandin E2. SP-GD (10 mg/kg) was also able to reduce neutrophil migration and the activity of the myeloperoxidase enzyme in carrageenan-induced peritonitis, as well as conserve glutathione concentration and reduce malondialdehyde levels in the animals' peritoneal fluid. Furthermore, it showed antinociceptive action in the abdominal writhing test induced by acetic acid and in the paw licking test induced by formalin. Thus, the results obtained allow us to infer that SPs extracted from G. domingensis at a dose of 10 mg/kg have anti-inflammatory effects by reducing neutrophil migration and modulating the activity of vasoactive mediators and antinociceptive effects by acting, at least in part, through a peripheral mechanism dependent on the negative modulation of inflammatory mediators.

Sulfated polysaccharide from Antrodia cinnamomea mycelium cultured with zinc sulfate stimulates M1 polarization of macrophages through AKT/mTOR pathways

Antrodia cinnamomea-derived sulfated polysaccharides (Ac-SPSs) have health benefits, but their yield is low. This study explores a strategy to increase Ac-SPS yield and elucidates the biofunctions of Ac-SPS. For this, A. cinnamomea mycelia were treated with zinc sulfate (ZnSO4) administered at 1, 10, and 100 μM. Firstly, functional assay indicated that ZnSO4 increases the Ac-SPS yield by 20 %-30 % compared with the control treatment. ZnSO4 engenders a population of middle-molecular-weight (~200 kDa) Ac-SPSs. Ac-SPS (ASZ-10) from A. cinnamomea treated with 10 μM ZnSO4 exhibits the best anti-proliferation ability against lung cancer A549 cells. Co-treatment of ASZ-10 does not inhibit lipopolysaccharide-induced inflammation but does induce M1-related markers of macrophage RAW264.7 cells. Secondly, immunomodulatory properties showed that ASZ-10 increases the expression of CD80+ and CD86+ in M-CSF-stimulated bone-marrow-derived macrophages. ASZ-10 induces M1 polarization through up-regulation of the AKT/mTOR pathway as confirmed by AKT and mTOR inhibitors eliminating ASZ-10-induced M1-like markers of macrophages. Through systemic chemical and functional analysis, this study shows that trace amounts (10 μM) of ZnSO4 increase Ac-SPS yield and it reveals that ASZ-10 exhibits anti-cancer activity and acts as a stimulator for M1 macrophages by stimulation of AKT and mTOR.

A study on anticancer and antioxidant ability of selected brown algae biomass yielded polysaccharide and their chemical and structural properties analysis by FT-IR and NMR analyses

The study was conducted to determine the chemical and structural properties of polysaccharides extracted from the marine macroalgae Nemalion cari-cariense. Furthermore, evaluate the anticancer and free radical scavenging activity of purified N. cari-cariense polysaccharide. Approximately 41.6% (w/w) of crude polysaccharide was extracted from N. cari-cariense macroalgae biomass. After deproteinization, the purified polysaccharide's major chemical composition was found to be 92.6%, with all protein content removed. The purified polysaccharide had ash and moisture % of 23.01% and 4.03%, respectively. The C, H, and N of the test polysaccharide were analyzed using GC-MS, with results of 39.21%, 5.87%, and 4.29%, respectively. Furthermore, this analysis also revealed the monosaccharide composition such as glucose, galactose, mannose, xylose, and rhamnose glucose, galactose, mannose, xylose, and rhamnose 54.62%, 29.64%, 2.8%, 5.9%, and 6.8% respectively. The molecular weight of purified polysaccharide was found as 49 kDa through PAGE analysis. The FT-IR analysis revealed that the presence of functional groups exactly attributed to polysaccharide and 1H and 13C-NMR analyses confirmed the structural properties of N. cari-cariense polysaccharide. The free radicals scavenging ability of purified N. cari-cariense polysaccharide was investigated by various assays such as total antioxidant assay (22.3%-72.5% at 50-250 μg mL-1), DPPH assay (23.6%-76.9% at 10-160 μg mL-1), OH radical scavenging assay (13.6%-70.2% at 50-250 μg mL-1 dosage, and SO radical scavenging assay (27.6-68.41% at 50-250 μg mL-1 concentration). The polysaccharide demonstrated 82.63% anticancer activity towards the A549 lung cancer cell line at 1000 μg mL-1 dosage. The findings suggest that this polysaccharide has biological applications.

Anticoagulant Protective Effects of Sulfated Chitosan Derived From the Internal Bone of Spineless Cuttlefish (Sepiella inermis)

Background This study investigated the anticoagulant properties of sulfated chitosan derived from the internal bone of the spineless cuttlefish Sepiella inermis. Chitosan, a biopolymer, is used in various biomedical applications including anticoagulation. Sulfation of chitosan enhances its biological activity, making it a potential therapeutic agent. This study explored the efficacy of sulfated chitosan in preventing blood clot formation to provide a novel anticoagulant alternative. Objectives This study aimed to synthesize and characterize the anticoagulant properties of sulfated chitosan extracted from the internal bone of the spineless cuttlefish S. inermis using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and X-Ray Diffraction (XRD) and evaluate the anticoagulant properties of sulfated chitosan extracted from the internal bone of spineless cuttlefish S. inermis. Materials and methods Chitin and chitosan were extracted from the cuttlebone of a specimen of S. inermis, and sulfated chitosan was synthesized by sulfation of chitosan. Sulfated chitosan was subsequently used to evaluate its anticoagulant properties using tests such as activated partial thromboplastin time (APTT) and prothrombin time (PT). Characteristic investigations were conducted, including FTIR, FESEM, and XRD analyses. Results The results of this study suggested the possibility of using S. inermis internal bone as an unconventional source of natural anticoagulant that can be combined with biomedical applications. Anticoagulant activity measured using APTT and PT showed that sulfated chitosan was a strong anticoagulant. Conclusion We examined the anticoagulant activity of S. inermis extract using thrombin and activated partial thromboplastin times. Our results demonstrated the heparin-like anticoagulant action of the extracted sulfated chitosan, suggesting that it may be a great alternative anticoagulant treatment.

Anti-herpes simplex virus activities and mechanisms of marine derived compounds

Herpes simplex virus (HSV) is the most widely prevalent herpes virus worldwide, and the herpetic encephalitis and genital herpes caused by HSV infection have caused serious harm to human health all over the world. Although many anti-HSV drugs such as nucleoside analogues have been ap-proved for clinical use during the past few decades, important issues, such as drug resistance, toxicity, and high cost of drugs, remain unresolved. Recently, the studies on the anti-HSV activities of marine natural products, such as marine polysaccharides, marine peptides and microbial secondary metabolites are attracting more and more attention all over the world. This review discusses the recent progress in research on the anti-HSV activities of these natural compounds obtained from marine organisms, relating to their structural features and the structure-activity relationships. In addition, the recent findings on the different anti-HSV mechanisms and molecular targets of marine compounds and their potential for therapeutic application will also be summarized in detail.

Preparation, structural characterization, bioactivities, and applications of Crataegus spp. polysaccharides: A review

Crataegus, is a genus within the Rosaceae family. It is recognized as a valuable plant with both medicinal and edible qualities, earning it the epithet of the "nutritious fruit" owing to its abundant bioactive compounds. Polysaccharides are carbohydrate polymers linked by glycosidic bonds, one of the crucial bioactive ingredients of Crataegus spp. Recently, Crataegus spp. polysaccharides (CPs) have garnered considerable attention due to their diverse range of bioactivities, including prebiotic, hypolipidemic, anticancer, antibacterial, antioxidant, and immunobiological properties. Herein, we provide a comprehensive overview of recent research on CPs. The analysis revealed that CPs exhibited a broad molecular weight distribution, ranging from 5.70 Da to 4.76 × 108 Da, and are composed of various monosaccharide constituents such as mannose, rhamnose, and arabinose. Structure-activity relationships demonstrated that the biological function of CPs is closely associated with their molecular weight, galacturonic acid content, and chemical modifications. Additionally, CPs have excellent bioavailability, biocompatibility, and biodegradability, which make them promising candidates for applications in the food, medicine, and cosmetic industries. The article also scrutinized the potential development and future research directions of CPs. Overall, this article provides comprehensive knowledge and underpinnings of CPs for future research and development as therapeutic agents and multifunctional food additives.

The Separation, Purification, Structure Identification, and Antioxidant Activity of Elaeagnus umbellata Polysaccharides

In order to investigate the antioxidant activity of Elaeagnus umbellata polysaccharides, the physicochemical characteristics of purified Elaeagnus umbellata polysaccharides (EUP, consisting of two fractions, EUP1 and EUP2) were investigated using UV spectrophotometry, high-performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC), and Fourier transform infrared spectroscopy (FT-IR). This revealed that EUP1 and EUP2 were acidic polysaccharides with an average molecular weight (MW) of 63 and 38 kDa, respectively. EUP1 mainly consisted of L-rhamnose and D-galactose in a molar ratio of 2.05:1, and EUP2 consisted of D-mannose, L-rhamnose, D-galactose, and D-arabinose in a molar ratio of 2.06:1:2.78:1. Furthermore, EUP exhibited considerable antioxidant potential for scavenging hydroxyl, superoxide anion, DPPH, and ABTS radicals. Therefore, EUP can be developed as a potential antioxidant for the functional food or pharmaceutical field.

Bioactivity of Fucoidan-Rich Extracts from Fucus vesiculosus against Rotavirus and Foodborne Pathogens

Marine algae are sources of bioactive components with defensive properties of great value against microbial infections. This study investigated the bioactivity of extracts from brown algae Fucus vesiculosus against rotavirus, the worldwide leading cause of acute gastroenteritis in infants and young children. Moreover, one of the extracts was tested against four foodborne bacteria: Campylobacter jejuni, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes, and the non-pathogenic: E. coli K12. In vitro tests using MA104 cells revealed that both whole algae extracts and crude fucoidan precipitates neutralized rotavirus in a dose-responsive manner. The maximum neutralization activity was observed when the rotavirus was incubated with 100 μg mL-1 of the hydrochloric acid-obtained crude fucoidan (91.8%), although crude fucoidan extracted using citric acid also demonstrated high values (89.5%) at the same concentration. Furthermore, molecular weight fractionation of extracts decreased their antirotaviral activity and high molecular weight fractions exhibited higher activity compared to those of lower molecular weight. A seaweed extract with high antirotaviral activity was also found to inhibit the growth of C. jejuni, S. Typhimurium, and L. monocytogenes at a concentration of 0.2 mg mL-1. Overall, this study expands the current knowledge regarding the antimicrobial mechanisms of action of extracts from F. vesiculosus.

The Anti-Inflammatory Effect of Low Molecular Weight Fucoidan from Sargassum siliquastrum in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages via Inhibiting NF-κB/MAPK Signaling Pathways

Brown seaweed is a rich source of fucoidan, which exhibits a variety of biological activities. The present study discloses the protective effect of low molecular weight fucoidan (FSSQ) isolated from an edible brown alga, Sargassum siliquastrum, on lipopolysaccharide (LPS)-stimulated inflammatory responses in RAW 264.7 macrophages. The findings of the study revealed that FSSQ increases cell viability while decreasing intracellular reactive oxygen species production in LPS-stimulated RAW 264.7 macrophages dose-dependently. FSSQ reduced the iNOS and COX-2 expression, inhibiting the NO and prostaglandin E2 production. Furthermore, mRNA expression of IL-1β, IL-6, and TNF-α was downregulated by FSSQ via modulating MAPK and NF-κB signaling. The NLRP3 inflammasome protein complex, including NLRP3, ASC, and caspase-1, as well as the subsequent release of pro-inflammatory cytokines, such as IL-1β and IL-18, release in LPS-stimulated RAW 264.7 macrophages was inhibited by FSSQ. The cytoprotective effect of FSSQ is indicated via Nrf2/HO-1 signaling activation, which is considerably reduced upon suppression of HO-1 activity by ZnPP. Collectively, the study revealed the therapeutic potential of FSSQ against inflammatory responses in LPS-stimulated RAW 264.7 macrophages. Moreover, the study suggests further investigations on commercially viable methods for fucoidan isolation.

Potential of Seaweeds to Mitigate Production of Greenhouse Gases during Production of Ruminant Proteins

The potential of seaweed to mitigate methane is real and studies with red seaweeds have found reductions in methane produced from ruminants fed red seaweeds in the region of 60-90% where the active compound responsible for this is bromoform. Other studies with brown and green seaweeds have observed reductions in methane production of between 20 and 45% in vitro and 10% in vivo. Benefits of feeding seaweeds to ruminants are seaweed specific and animal species-dependent. In some instances, positive effects on milk production and performance are observed where selected seaweeds are fed to ruminants while other studies note reductions in performance traits. A balance between reducing methane and maintaining animal health and food quality is necessary. Seaweeds are a source of essential amino acids and minerals however, and offer huge potential for use as feeds for animal health maintenance once formulations and doses are correctly prepared and administered. A negative aspect of seaweed use for animal feed currently is the cost associated with wild harvest and indeed aquaculture production and improvements must be made here if seaweed ingredients are to be used as a solution to control methane production from ruminants for continued production of animal/ruminant sourced proteins in the future. This review collates information concerning different seaweeds and how they and their constituents can reduce methane from ruminants and ensure sustainable production of ruminant proteins in an environmentally beneficial manner.

Formulation of Polymeric Microparticles Using Eco-Friendly Extracted Crude Fucoidans from Edible Brown Seaweed Undaria pinnatifida

Several bioactive compounds that hold a potential interest in the food industry as phenolic compounds, polysaccharides, proteins and vitamins, among others, are present in seaweeds. Green extraction technologies are the preferred way to obtain these compounds. Pressurized hot water extraction, from 160 to 220 °C, was tested to achieve high yields of these components from the edible brown seaweed, Undaria pinnatifida. The maximum fucoidan content was recovered at 160 °C, while the phloroglucinol content and antioxidant activity were maximum at 220 °C. The possibility of encapsulating these bioactive fractions using mannitol was assessed. The highest production yield of the polymeric particles was found using the 220 °C fraction (close to 75%). In order to formulate microparticles with bioactive potential, several ratios of liquid phases were assessed, 3:1, 1:1 and 1:3 (w:w), using the liquid fractions obtained at 160 °C and 220 °C. The yield production was always above 67%, being in the 1:3 ratio (160 °C:220 °C) and close to 75%. The rheological results indicated that the presence of microparticles enhanced the apparent viscosity of the aqueous dispersions with non-Newtonian profiles, achieving the highest viscosity for those formulated with microparticles from 160 °C:200 °C (3:1).

The Potential Effect of Polysaccharides Extracted from Red Alga Gelidium spinosum against Intestinal Epithelial Cell Apoptosis

Gut injury is a severe and unpredictable illness related to the increased cell death of intestinal epithelial cells (IECs). Excessive IEC apoptotic cell death during the pathophysiological state entails chronic inflammatory diseases. This investigation was undertaken to assess the cytoprotective action and underlying mechanisms of polysaccharides from Tunisian red alga, Gelidium spinosum (PSGS), on H2O2-induced toxicity in IEC-6 cells. The cell viability test was initially carried out to screen out convenient concentrations of H2O2 and PSGS. Subsequently, cells were exposed to 40 µM H2O2 over 4 h in the presence or absence of PSGS. Findings revealed that H2O2 caused oxidative stress manifested by over 70% cell mortality, disturbed the antioxidant defense, and increased the apoptotic rate in IEC-6 cells (32% than normal cells). Pretreatment of PSGS restored cell viability, especially when used at 150 µg/mL and normal cell morphology in H2O2-callenged cells. PSGS also equally sustained superoxide dismutase and catalase activities and hindered the apoptosis induced by H2O2. This protection mechanism of PSGS may be associated with its structural composition. The ultraviolet visible spectrum, Fourier-transformed infrared (FT-IR), X-ray diffraction (XRD), and high-performance liquid chromatography (HPLC) demonstrated that PSGS is mainly sulfated polysaccharides. Eventually, this research work provides a deeper insight into the protective functions and enhances the investment of natural resources in handling intestinal diseases.

Biological active metabolites from microalgae for healthcare and pharmaceutical industries: A comprehensive review

Microalgae are photoautotrophic microorganisms which comprise of species from several phyla. Microalgae are promising in producing a varieties of products, including food, feed supplements, chemicals, and biofuels. Medicinal supplements derived from microalgae are of a significant market in which compounds such as -carotene, astaxanthin, polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and polysaccharides such as -glucan, are prominent. Microalgae species which are commonly applied for commercial productions include Isochrysis sp., Chaetoceros (Chlorella sp.), Arthrospira sp. (Spirulina Bioactive) and many more. In this present review, microalgae species which are feasible in metabolites production are being summarized. Metabolites produced by microalgae as well as their prospective applications in the healthcare and pharmaceutical industries, are comprehensively discussed. This evaluation is greatly assisting industrial stakeholders, investors, and researchers in making business decisions, investing in ventures, and moving the production of microalgae-based metabolites forward.

Fucoidan from Fucus vesiculosus: Evaluation of the Impact of the Sulphate Content on Nanoparticle Production and Cell Toxicity

The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200-300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT-116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675-100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Structural and functional properties of alginate obtained by means of high hydrostatic pressure-assisted extraction

The effects of the high hydrostatic pressure (HPP) pre-treatment on the alginate extraction were seen to greatly depend on the recalcitrant nature of two algae species. Alginates were deeply characterized in terms of composition, structure (HPAEC-PAD, FTIR, NMR, SEC-MALS), functional and technological properties. The pre-treatment significantly increased the alginate yield in the less recalcitrant A. nodosum (AHP) also favoring the extraction of sulphated fucoidan/fucan structures and polyphenols. Although the molecular weight was significantly lower in AHP samples, neither the M/G ratio nor the M and G sequences were modified. In contrast, a lower increase in alginate extraction yield was observed for the more recalcitrant S. latissima after the HPP pre-treatment (SHP), but it significantly affected the M/G values of the resulting extract. The gelling properties of the alginate extracts were also explored by external gelation in CaCl₂ solutions. The mechanical strength and nanostructure of the hydrogel beads prepared were determined using compression tests, synchrotron small angle X-ray scattering (SAXS), and cryo-scanning electron microscopy (Cryo-SEM). Interestingly, the application of HPP significantly improved the gel strength of SHP, in agreement with the lower M/G values and the stiffer rod-like conformation obtained for these samples.

Complete organellar genomes of six Sargassum species and development of species-specific markers

Sargassum is one of the most important brown algal genera that can be used as food and raw material for medicinal purpose, and has various beneficial effects. As the classification of Sargassum species is currently based on their morphological characteristics, organellar genome sequences of Sargassum would provide important information for accurate identification of species and developing species-specific markers. We sequenced the complete organellar genomes of six Sargassum species, including the first complete chloroplast genome sequences of S. fulvellum, S. serratifolium, S. macrocarpum, and S. siliquastrum, and the first complete mitochondrial genome sequences of S. fulvellum, S. serratifolium, and S. macrocarpum. The chloroplast genomes of the 6 Sargassum species contained 139 protein-coding genes (PCGs), and the mitochondrial genomes possessed 37 PCGs. A comparative study was performed between the newly sequenced organellar genomes and 44 other species belonging to class Phaeophyceae. Phylogenetic relationships using PCGs shared by Phaeophyceae species were constructed with IQ-TREE 2 using the maximum likelihood method. In addition, we developed real-time PCR markers based on SNPs to distinguish the 6 Sargassum species. Our results provide useful information for establishing phylogenetic relationships between brown algae.

Marine biome-derived secondary metabolites, a class of promising antineoplastic agents: A systematic review on their classification, mechanism of action and future perspectives

Cancer is one of the most deadly diseases on the planet. Over the past decades, numerous antineoplastic compounds have been discovered from natural resources such as medicinal plants and marine species as part of multiple drug discovery initiatives. Notably, several marine flora (e.g. Ascophyllum nodosum, Sargassum thunbergii) have been identified as a rich source for novel cytotoxic compounds of different chemical forms. Despite the availability of enormous chemically enhanced new resources, the anticancer potential of marine flora and fauna has received little attention. Interestingly, numerous marine-derived secondary metabolites (e.g., Cytarabine, Trabectedin) have exhibited anticancer effects in preclinical cancer models. Most of the anticancer drugs obtained from marine sources stimulated apoptotic signal transduction pathways in cancer cells, such as the intrinsic and extrinsic pathways. This review highlights the sources of different cytotoxic secondary metabolites obtained from marine bacteria, algae, fungi, invertebrates, and vertebrates. Furthermore, this review provides a comprehensive overview of the utilisation of numerous marine-derived cytotoxic compounds as anticancer drugs, as well as their modes of action (e.g., molecular target). Finally, it also discusses the future prospects of marine-derived drug developments and their constraints.

Apoptotic and Antioxidant Activity of Gold Nanoparticles Synthesized Using Marine Brown Seaweed: An In Vitro Study

A major paradigm shift in the field of nanobiotechnology is the invention of an eco-friendly, economical, and green approach for synthesis of metal nanoparticles. In the present study, we have synthesized gold nanoparticles (AuNPs) using aqueous extracts of marine brown seaweed Sargassum longifolium. The synthesized nanoparticle was subjected to characterization using different techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy, atomic force microscope, scanning electron microscope, transmission electron microscope, and elemental dispersive X-ray diffraction. Further, the seaweed extract and the synthesized AuNPs were evaluated for its anticancer effect using MG-63 human osteosarcoma cells besides in vitro antioxidant effect. The formation of S. longifolium-mediated synthesis of gold nanoparticles was demonstrated by UV-Vis spectroscopy. Presence of elemental gold was confirmed by EDX analysis. TEM analysis demonstrated spherical morphology of the synthesized AuNPs and SEM analysis revealed the particle size to be in the range of 10-60 nm. The FTIR showed the presence of hydroxyl functional groups. The toxicity of S. longifolium extract and the synthesized AuNPs was tested using brine shrimp lethality assay at different concentrations with results showing both seaweed extract and AuNPs to be nontoxic. Both S. longifolium and AuNPs exhibited significant antioxidant activity by scavenging DPPH free radicals and H2O2 radicals. Significant antiproliferative effect was observed against MG-63 osteosarcoma cells. It was also shown that the seaweed extract and the AuNPs induced cytotoxicity in cell lines by mechanism of apoptosis. In conclusion, this study provided insight on AuNPs synthesized from S. longifolium as a potent antioxidant and anticancer agent.

Nutraceutical potential of polyphenol-rich Sargassum species grown off the Korean coast: a review

Sargassum, a brown seaweed, has been used traditionally as food and medicine in Korea, China, and Japan. Sargassum spp. contain bioactive substances associated with health benefits, including anti-inflammatory and antioxidant effects. Thirty Sargassum spp. inhabit the Korean coast. However, their health benefits have yet to be systematically summarized. Therefore, the purpose of this article was to review the health benefits of these 30 Sargassum spp. grown off the Korean coast based on their health benefits, underlying mechanisms, and identified bioactive compounds.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01050-x.

Nutritional and Chemical Composition of Sargassum zhangii and the Physical and Chemical Characterization, Binding Bile Acid, and Cholesterol-Lowering Activity in HepG2 Cells of Its Fucoidans

Fucoidan is a marine sulfated polysaccharide that is rich in Sargassum and has a wide range of biological activities. In this study, the chemical composition and bile acid binding ability of six crude fucoidans were compared, the nutrition and chemical composition of Sargassum zhangii were analyzed, and fucoidan from Sargassum zhangii was extracted and purified. The purified fractions (ZF1, ZF2, and ZF3) were analyzed by physicochemical characterization, and the ability of binding bile acid and cholesterol lowering in HepG2 cells were evaluated. The results showed that the contents of sulfate in crude fucoidan from Sargassum Zhangii (ZF) was as high as13.63%. Its ability of binding bile acid was better than other five crude fucoidans. Sargassum zhangii was a kind of brown seaweed with high carbohydrate, and low fat and rich in minerals. The sulfate content of ZF1, ZF2, and ZF3 was 3.29%, 19.39%, and 18.89% respectively, and the molecular weight (Mw) was 4.026 × 10⁵, 2.893 × 10⁵, and 3.368 × 10⁵, respectively. Three fucoidans all contained the characteristic absorption bands of polysaccharides and sulfate groups and were rich in fucose. Three fucoidans can bind to bile acid, and ZF2 showed the best binding capability. In vitro experiments showed that ZF1, ZF2, and ZF3 could reduce intracellular total cholesterol (TC) content in HepG2 cells without affecting their viability. ZF2 showed the best ability to reduce TC.

Phlorotannins of the Brown Algae Sargassum vulgare from the Mediterranean Sea Coast

Brown seaweeds are a good source of bioactive compounds, particularly of phlorotannins, which may exert a wide spectrum of pharmacological properties. In the present study, phlorotannins of S. vulgare were extracted using a 70% acetone solution and the crude extract was further purified through liquid–liquid partition, giving rise to n-hexane, ethyl acetate and aqueous residue fractions. The crude extract and the purified fractions were evaluated for potential antioxidant abilities as well as for inhibitory potential towards the digestive enzymes α-amylase and pancreatic lipase, and anti-inflammatory potential through the hindering of albumin denaturation. Overall, the ethyl acetate fraction was the richest in phlorotannins (9.4 ± 0.03 mg PGE/g) and was also the most promising regarding the tested bioactive properties. Of note, its inhibitory potential towards α-amylase was about nine times that of the commercial drug acarbose and its inhibitory activity against high temperature-induced protein denaturation was superior to that of the non-steroidal drug ketoprofen. According to UHPLC-DAD-ESI-MS/MS analysis, this fraction contained a range of phlorotannins with at least six units of phloroglucinol, including dibenzodioxine-1,3,6,8-tetraol, fuhalol, pentaphlorethol, fucopentaphlorethol and dihydroxypentafuhalol, in addition to several less common phlorotannin sulfate derivatives.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Effects of dietary Gracilaria persica on the intestinal microflora, thyroid hormones, and resistance against Aeromonas hydrophila in Persian sturgeon (Acipenser persicus)

Red seaweeds have several biomedical derivatives making them healthy additives for the aquaculture industry. Previously we reported enhanced growth performance, feed utilization, and immunity of Persian sturgeon treated with Gracilaria gracilis. Herein, we investigated the effects of G. gracilis on the intestinal microflora, thyroid hormones, and resistance against Aeromonas hydrophila in Persian sturgeon. Fish fed G. gracilis at 0, 2.5, 5, and 10 g/kg for eight weeks, then challenged with A. hydrophila for ten days. The results showed that the total bacterial count in the fish intestines had no meaningful differences among the groups of fish fed varying levels of G. persica (P˃0.05). Fish fed 10 g/kg of G. persica had a higher lactic acid bacteria (LAB) count than fish fed 0, 2.5, and 5 g/kg (P<0.05). Serum thyroid-stimulating hormone (TSH) showed higher levels in fish treated with 2.5 and 5 g/kg of G. persica than the other groups (P<0.05). Besides, fish fed 2.5 g/kg G. persica had higher thyroxine (T4) and triiodothyronine (T3) levels than the other groups (P<0.05). At the end of the challenge test, the highest mortality was seen in the fish fed the G. persica free diet. In summary, Persian sturgeon treated G. gracilis had improved intestinal microflora, thyroid hormones, and resistance against A. hydrophila.

Serial Extraction Technique of Rich Antibacterial Compounds in Sargassum cristaefolium Using Different Solvents and Testing their Activity

Background:

Sargassum cristaefolium, as one of the brown seaweeds locally found in Indonesia, is extracted using the serial technique employing different solvents.

Methods:

S. cristaefolium powder (50 mesh) was extracted with three different solvents, including hexane, ethyl acetate, and methanol. S. cristaefolium powder residue was dried prior to serial re-extraction using different solvents. Three serial extracts were obtained and named as 1-stage extract, 2-stage extract, and 3-stage extract. Besides, a single-step extract (i.e., extraction using only methanol) was produced to be compared with three serial extracts in antibacterial activity tests (against E. coli and S. aureus). The three serial extracts were detected for their antibacterial compounds using GC-MS, LC-HRMS, and FT-IR.

Results:

The 3-stage extract exhibited the highest extraction yield. On S. aureus, the inhibition zone in all extracts was not significantly different. On E.coli, the highest inhibition zone (5.42±0.14 mm) was of the 3-stage extract; indeed, it was higher than both antibiotic and a single- step extract. Antibacterial compounds, such as phenol, 9-Tricosene(Z)-, palmitic acid, and oleamide, were present in all extracts. Other antibacterial compound types, both the 1-stage and 2-stage extracts, contained 7 types, whilst the 3-stage extract contained the most types (11 types). Particularly, hexyl cinnamic aldehyde, betaine and several cinnamic aldehyde groups were detected only in the 3-stage extract comprising the dominant area. The carboxylic acid groups were detected in all extracts to confirm the fatty acid structure.

Conclusions:

The serial extraction technique could produce the 3-stage extract which exhibited the strongest antibacterial activity and contained the richest antibacterial compounds.

Characterization and Functionality of Cellulose from Pomelo Fruitlets by Different Extraction Methods

Pomelo fruitlets have the potential for extracting cellulose. This study aimed to investigate characterization and functionality of cellulose extracted from pomelo fruitlets by different extraction methods. Cellulose extracted by acidic-alkaline hydrogen peroxide hydrolysis (CAA), alkaline hydrogen peroxide hydrolysis (CA), and ultrasonic assisted alkaline hydrogen peroxide hydrolysis (CUA) were prepared from pomelo fruitlets. The results showed that cellulose CUA had higher yield and purity with higher crystallinity and smaller particle size than those of CAA or CA (p < 0.05). Specifically, the yield of CUA was 82.75% higher than that of CAA, and purity was increased by 26.42%. Additionally, water- and oil-holding capacities of CUA were superior to those of CAA or CA, increasing by 13–23% and 10–18%, respectively. The improvement of water- and oil-holding capacities were highly related to its smaller particle size with increased surface area. The results suggested that ultrasonic assisted alkaline hydrogen peroxide hydrolysis is a promising and efficient method to prepare high-purity cellulose from pomelo fruitlets, and this cellulose is expected to be a food stabilizer and pharmaceutical additive.

Evaluation of seaweed sulfated polysaccharides as natural antagonists targeting Salmonella typhi OmpF: molecular docking and pharmacokinetic profiling

Background

Salmonella belongs to the Enterobacteriaceae family, a gram-negative, non-spore-forming, rod-shaped, motile, and pathogenic bacteria that transmit through unhygienic conditions. It is estimated that 21 million new infections arise every year, resulting in approximately 200,000 deaths. It is more prevalent among children, the old aged, and immunocompromised individuals. The frequent usage of classical antimicrobials has begun the increasing emergence of various drug-resistant pathogenic bacterial strains. Hence, this study was intended to evaluate the bioactive seaweed sulfated polysaccharides (SSPs) against the ompF (outer membrane porin F) protein target of Salmonella typhi. SSP is the sulfated compound with a wide range of biological activities, such as anti-microbial, anti-allergy, anti-cancer, anti-coagulant, anti-inflammation, anti-oxidant, and anti-viral.

Results

In this study, eleven compounds were targeted against S. typhi OmpF by the molecular docking approach and were compared with two commercially available typhoid medications. The SSP showed good binding affinity compared to commercial drugs, particularly carrageenan/MIV-150, carrageenan lambda, fucoidan, and 3-phenyllactate, ranked as top antagonists against OmpF. Further, pharmacokinetics and toxicology (ADMET) studies corroborated that SSP possessed drug-likeness and highly progressed in all parameters.

Conclusions

AutoDockTools and Schrodinger's QikProp module results suggest that SSP could be a promising drug for extensively drug-resistant (XDR) S. typhi. To the best of our knowledge, this is the first report on in silico analysis of SSP against S. typhi OmpF, thus implying the capabilities of SSPs especially compounds like carrageenans, as a potential anti-microbial agent against Salmonella typhi infections. Eventually, advanced studies could corroborate SSPs to the next level of application in the crisis of XDR microbial diseases.

Graphical Abstract

Fucoidan and Alginate from the Brown Algae Colpomenia sinuosa and Their Combination with Vitamin C Trigger Apoptosis in Colon Cancer

Brown seaweeds are producers of bioactive molecules which are known to inhibit oncogenic growth. Here, we investigated the antioxidant, cytotoxic, and apoptotic effects of two polysaccharides from the brown algae Colpomenia sinuosa, namely fucoidan and alginate, in a panel of cancer cell lines and evaluated their effects when combined with vitamin C. Fucoidan and alginate were isolated from brown algae and characterized by HPLC, FTIR, and NMR spectroscopy. The results indicated that highly sulfated fucoidans had higher antioxidant and cytotoxic effects than alginate. Human colon cancer cells were the most sensitive to the algal treatments, with fucoidan having an IC50 value (618.9 µg/mL-1) lower than that of alginate (690 µg/mL-1). The production of reactive oxygen species was increased upon treatment of HCT-116 cells with fucoidan and alginate, which suggest that these compounds may trigger cell death via oxidative damage. The combination of fucoidan with vitamin C showed enhanced effects compared to treatment with fucoidan alone, as evidenced by the significant inhibitory effects on HCT-116 colon cancer cell viability. The combination of the algal polysaccharides with vitamin C caused enhanced degeneration in the nuclei of cells, as evidenced by DAPI staining and increased the subG1 population, suggesting the induction of cell death. Together, these results suggest that fucoidan and alginate from the brown algae C. sinuosa are promising anticancer compounds, particularly when used in combination with vitamin C.

Recent advances in industrial applications of seaweeds

Seaweeds have been generally utilized as food and alternative medicine in different countries. They are specifically used as a raw material for wine, cheese, soup, tea, noodles, etc. In addition, seaweeds are potentially good resources of protein, vitamins, minerals, carbohydrates, essential fatty acids and dietary fiber. The quality and quantity of biologically active compounds in seaweeds depend on season and harvesting period, seaweed geolocation as well as ecological factors. Seaweeds or their extracts have been studied as innovative sources for a variety of bioactive compounds such as polyunsaturated fatty acids, polyphenols, carrageenan, fucoidan, etc. These secondary metabolites have been shown to have antioxidant, antimicrobial, antiviral, anticancer, antidiabetic, anti-inflammatory, anti-aging, anti-obesity and anti-tumour properties. They have been used in pharmaceutical/medicine, and food industries since bioactive compounds from seaweeds are regarded as safe and natural. Therefore, this article provides up-to-date information on the applications of seaweed in different industries such as pharmaceutical, biomedical, cosmetics, dermatology and agriculture. Further studies on innovative extraction methods, safety issue and health-promoting properties should be reconsidered. Moreover, the details of the molecular mechanisms of seaweeds and their bioactive compounds for physiological activities are to be clearly elucidated.

Fucoidan Modulated Oxidative Stress and Caspase-3 mRNA Expression Induced by Sulfoxaflor in the Brain of Mice

The current study aimed to investigate the role of fucoidan in the oxidative and apoptotic effects of sulfoxaflor, a neonicotinoid sulfoximine insecticide, in the brain of Swiss albino mice (Mus musculus). Sulfoxaflor and fucoidan were administered to mice at doses of 15 mg/kg/day (1/50 oral LD50) and 50 mg/kg/day, respectively, by oral gavage for 24 h or 7 days. The tGSH, TBARS and protein levels, and GPx, GR, and GST enzyme activities were determined by spectrophotometric methods. Caspase-3 gene expression level was determined by RT-PCR. Data analysis showed that brains of sulfoxaflor-treated mice exhibited higher TBARS levels; GPx, GR, and GST enzyme activities; and caspase-3 expression levels, as well as lower levels of tGSH. Co-administration of fucoidan and sulfoxaflor reduced the TBARS levels, increased tGSH levels, and increased GPx, GR, and GST enzyme activities. Fucoidan also decreased the sulfoxaflor-induced up-regulation of caspase-3 mRNA expression. Results of the present study showed that sulfoxaflor caused oxidative stress by inducing lipid peroxidation and altering GSH-dependent antioxidants in the brain of mice. In addition, sulfoxaflor may trigger apoptotic cell death shown by the up-regulation of caspase-3. Fucoidan treatment modulated all the aforementioned alterations in the brain of mice. It was concluded that fucoidan might have antioxidant effects that support the GSH-dependent antioxidant system and can play a modulator role in oxidative stress and caspase-3 expression in the brain of sulfoxaflor treated-mice.

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.

The Antiviral Activity of Bacterial, Fungal, and Algal Polysaccharides as Bioactive Ingredients: Potential Uses for Enhancing Immune Systems and Preventing Viruses

Viral infections may cause serious human diseases. For instance, the recent appearance of the novel virus, SARS-CoV-2, causing COVID-19, has spread globally and is a serious public health concern. The consumption of healthy, proper, functional, and nutrient-rich foods has an important role in enhancing an individual's immune system and preventing viral infections. Several polysaccharides from natural sources such as algae, bacteria, and fungi have been considered as generally recognized as safe (GRAS) by the US Food and Drug Administration. They are safe, low-toxicity, biodegradable, and have biological activities. In this review, the bioactive polysaccharides derived from various microorganisms, including bacteria, fungi, and algae were evaluated. Antiviral mechanisms of these polysaccharides were discussed. Finally, the potential use of microbial and algal polysaccharides as an antiviral and immune boosting strategy was addressed. The microbial polysaccharides exhibited several bioactivities, including antioxidant, anti-inflammatory, antimicrobial, antitumor, and immunomodulatory activities. Some microbes are able to produce sulfated polysaccharides, which are well-known to exert a board spectrum of biological activities, especially antiviral properties. Microbial polysaccharide can inhibit various viruses using different mechanisms. Furthermore, these microbial polysaccharides are also able to modulate immune responses to prevent and/or inhibit virus infections. There are many molecular factors influencing their bioactivities, e.g., functional groups, conformations, compositions, and molecular weight. At this stage of development, microbial polysaccharides will be used as adjuvants, nutrient supplements, and for drug delivery to prevent several virus infections, especially SARS-CoV-2 infection.

Applying Seaweed Compounds in Cosmetics, Cosmeceuticals and Nutricosmetics

The interest in seaweeds for cosmetic, cosmeceutics, and nutricosmetics is increasing based on the demand for natural ingredients. Seaweeds offer advantages in relation to their renewable character, wide distribution, and the richness and versatility of their valuable bioactive compounds, which can be used as ingredients, as additives, and as active agents in the formulation of skin care products. Bioactive compounds, such as polyphenols, polysaccharides, proteins, peptides, amino acids, lipids, vitamins, and minerals, are responsible for the biological properties associated with seaweeds. Seaweed fractions can also offer technical features, such as thickening, gelling, emulsifying, texturizing, or moistening to develop cohesive matrices. Furthermore, the possibility of valorizing industrial waste streams and algal blooms makes them an attractive, low cost, raw and renewable material. This review presents an updated summary of the activities of different seaweed compounds and fractions based on scientific and patent literature.

From Sea to Skin: Is There a Future for Natural Photoprotectants?

In the last few decades, the thinning of the ozone layer due to increased atmospheric pollution has exacerbated the negative effects of excessive exposure to solar ultraviolet radiation (UVR), and skin cancer has become a major public health concern. In order to prevent skin damage, public health advice mainly focuses on the use of sunscreens, along with wearing protective clothing and avoiding sun exposure during peak hours. Sunscreens present on the market are topical formulations that contain a number of different synthetic, organic, and inorganic UVR filters with different absorbance profiles, which, when combined, provide broad UVR spectrum protection. However, increased evidence suggests that some of these compounds cause subtle damage to marine ecosystems. One alternative may be the use of natural products that are produced in a wide range of marine species and are mainly thought to act as a defense against UVR-mediated damage. However, their potential for human photoprotection is largely under-investigated. In this review, attention has been placed on the molecular strategies adopted by marine organisms to counteract UVR-induced negative effects and we provide a broad portrayal of the recent literature concerning marine-derived natural products having potential as natural sunscreens/photoprotectants for human skin. Their chemical structure, UVR absorption properties, and their pleiotropic role as bioactive molecules are discussed. Most studies strongly suggest that these natural products could be promising for use in biocompatible sunscreens and may represent an alternative eco-friendly approach to protect humans against UV-induced skin damage.

Controlled sulfation of mixed-linkage glucan by Response Surface Methodology for the development of biologically applicable polysaccharides

Endogenous and exogenous sulfated polysaccharides exhibit potent biological activities, including inhibiting blood coagulation and protein interactions. Controlled chemical sulfation of alternative polysaccharides holds promise to overcome limited availability and heterogeneity of naturally sulfated polysaccharides. Here, we established reaction parameters for the controlled sulfation of the abundant cereal polysaccharide, mixed-linkage β(1,3)/β(1,4)-glucan (MLG), using Box-Behnken Design of Experiments (BBD) and Response Surface Methodology (RSM). The optimization of the degree-of-substitution (DS) was externally validated through the production of sulfated MLGs (S-MLGs) with observed DS and M_w values deviating less than 20% and 30% from the targeted values, respectively. Simultaneous optimization of DS and M_w resulted in the same range of deviation from the targeted value. S-MLGs with DS > 1 demonstrated a modest anticoagulation effect versus heparin, and a greater P-selectin affinity than fucoidan. As such, this work provides a route to medically important polymers from an economical agricultural polysaccharide.

The Application of Seaweed Polysaccharides and Their Derived Products with Potential for the Treatment of Alzheimer's Disease

Neurodegenerative diseases are among the most widespread diseases affecting humans, and the number of patients is only rising. Seaweed polysaccharide extracts show significant neuroprotective and reparative activities. Seaweed polysaccharides might provide the next big breakthrough in neurodegenerative disease treatment. This paper reviews the applications of seaweed polysaccharides as potential treatments of neurodegenerative diseases. The particular focus is on fucoidan, ulvan, and their derivatives as potential agents to treat Alzheimer's disease. This review provides a critical update on the progress in this important research area.

Polysaccharides obtained from natural edible sources and their role in modulating the immune system: Biologically active potential that can be exploited against COVID-19

BACKGROUND

The global crisis caused by the outbreak of severe acute respiratory syndrome caused by the SARS-CoV-2 virus, better known as COVID-19, brought the need to improve the population's immunity. The foods rich in polysaccharides with immunomodulation properties are among the most highly rated to be used as immune response modulators. Thus, the use of polysaccharides obtained from food offers an innovative strategy to prevent serious side effects of viral infections.

SCOPE AND APPROACH

This review revisits the current studies on the pathophysiology of SARS-CoV-2, its characteristics, target cell interactions, and the possibility of using polysaccharides from functional foods as activators of the immune response. Several natural foods are explored for the possibility of being used to obtain polysaccharides with immunomodulatory potential. And finally, we address expectations for the use of polysaccharides in the development of potential therapies and vaccines.

KEY FINDINGS AND CONCLUSIONS

The negative consequences of the SARS-CoV-2 pandemic across the world are unprecedented, thousands of lives lost, increasing inequalities, and incalculable economic losses. On the other hand, great scientific advances have been made regarding the understanding of the disease and forms of treatment. Polysaccharides, due to their characteristics, have the potential to be used as potential drugs with the ability to modulate the immune response. In addition, they can be used safely, as they have no toxic effects, are biocompatible and biodegradable. Finally, these biopolymers can still be used in the development of new therapies and vaccines.

Functional polysaccharides of fucoidan, laminaran and alginate from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana)

Brown seaweeds are rich source of functional polysaccharides that exhibit various bioactivities. However, Malaysian seaweeds are under-utilised, leading to low revenue throughout the supply chain of the seaweed industry. The aims of this study were to extract the functional polysaccharides, namely fucoidan (F), laminaran (L) and alginate (A) from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana) and subsequently evaluate the properties of the extracted polysaccharides. P. boryana recorded the significantly (p ≤ 0.05) highest carbohydrate content (74.78 ± 1.63%) with highest fucoidan yield (Fpad = 1.59 ± 0.16%) while T. ornata contained significantly (p ≤ 0.05) highest alginate yield (Atur = 105.19 ± 3.45%). Water activities of these extracted polysaccharides varied from 0.63-0.71 with average score of browning indexes (~40). Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that the extracted polysaccharides exhibited similar spectral pattern of spectra with the respective standards. Meanwhile, laminaran extracts showed the significantly highest (p ≤ 0.05) total phenolic contents (Lsar = 43.29 ± 0.43 mgGAE/g) and superoxide anion scavenging activity (Lsig = 21.7 ± 3.6%). On the other hand, the significantly highest (p ≤ 0.05) DPPH scavenging activity was recorded in alginate with Asar at 85.3 ± 0.8%. These findings reported the properties and bioactivities of natural polysaccharides from Malaysian brown seaweeds that revealed the potential to develop high-value functional ingredients from Malaysian brown seaweeds.

Characterization of polysaccharides from different species of brown seaweed using saccharide mapping and chromatographic analysis

Brown seaweed polysaccharides (BSPs) are one of the primary active components from brown seaweed that has a range of pharmaceutical and biomedical applications. However, the quality control of BSPs is a challenge due to their complicated structure and macromolecule. In this study, saccharide mapping based on high-performance liquid chromatography (HPLC), multi-angle laser light scattering, viscometer, and refractive index detector (HPSEC-MALLS-Vis-RID), and Fourier transform infrared (FT-IR) were used to discriminate the polysaccharides from nine different species of brown algae (BA1-9). The results showed that BSPs were composed of β-D-glucans and β-1,3-1,4-glucan linkages. The molecular weight, radius of gyration, and intrinsic viscosity of BSPs were ranging from 1.718 × 10⁵ Da to 6.630 × 10⁵ Da, 30.2 nm to 51.5 nm, and 360.99 mL/g to 865.52 mL/g, respectively. Moreover, α values of BSPs were in the range of 0.635 to 0.971, which indicated a rigid rod chain conformation. The antioxidant activities of BSPs exhibited substantial radical scavenging activities against DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2, 2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) radicals, which indicated that the use of BSPs might be a potential approach for antioxidant supplements. Thus, this study gives insights about the structure-function relationship of BSPs, which will be beneficial to improve the quality of polysaccharides derived from marine algae.

Recent Advances in Marine-Based Nutraceuticals and Their Health Benefits

The oceans have been the Earth's most valuable source of food. They have now also become a valuable and versatile source of bioactive compounds. The significance of marine organisms as a natural source of new substances that may contribute to the food sector and the overall health of humans are expanding. This review is an update on the recent studies of functional seafood compounds (chitin and chitosan, pigments from algae, fish lipids and omega-3 fatty acids, essential amino acids and bioactive proteins/peptides, polysaccharides, phenolic compounds, and minerals) focusing on their potential use as nutraceuticals and health benefits.