In vitro and in vivo immunomodulatory activity of sulfated polysaccharides from red seaweed Nemalion helminthoides

A critical review on pharmacological properties of sulfated polysaccharides from marine macroalgae

The marine ecosystem contains an assorted range of organisms, among which macroalgae stands out marine resources as an invaluable reservoir of structurally diverse bioactive compounds. Marine macroalgae are considered as primary consumers have gained more attention for their bioactive components. Sulfated polysaccharides (SPs) are complex polymers found in macroalgae that play a crucial role in their cell wall composition. This review consolidates high-tech methodologies employed in the extraction of macroalgal SPs, offering a valuable resource for researchers focuses in the pharmacological relevance of marine macromolecules. The pharmacological activities of SPs, focusing on their therapeutic action by encompassing diverse study models are summarized. Furthermore, in silico docking studies facilitates a comprehensive understanding of SPs interactions with their binding sites providing a valuable insight for future endeavors. The biological properties of algal SPs, along with a brief reference to mode of action based on different targets are presented. This review utilizes up-to-date research discoveries across various study models to elucidate the biological functions of SPs, focusing on their molecular-level mechanisms and offering insights for prospective investigations. Besides, the significance of SPs from seaweeds is highlighted, showcasing their potential beneficial applications in promoting human health. With promising biomedical prospects, this review explores the extensive uses and experimental evidence supporting the important roles of SPs in various fields.

Suaeda maritima polysaccharides attenuate LPS-induced inflammation of RAW264.7 cells and antioxidative activity

Our research focused on extracting polysaccharides from Suaeda maritima (SMP) to obtain crude polysaccharides (SMP-C), which were subsequently purified into SMP-F1 and SMP-F2. SMPs were evaluated for anti-inflammatory effects and SMP-F1 showed the highest inhibitory effects on nitric oxide (NO) production. The monosaccharide composition analysis of SMP-F1 (molecular weight of 112.2 × 103 g/mol) revealed predominant levels of glucose (45.4 %), arabinose (20.5 %), mannose (14.2 %), and galactose (12.7 %). The primary backbone of SMP-F1 consisted of (1 → 4)-D-glucopyranoside, (1 → 4,6)-D-glucopyranoside, (1 → 3)-D-mannopyranoside, (1 → 3,6)-D-mannopyranoside, and (1 → 5)-L-arabifuranoside. In addition, we hydrolysed SMP-F1 to SMP-H1, SMP-H2, and SMP-H3 and investigated their anti-inflammatory effects on RAW264.7 macrophages. Following SMP-F1 hydrolysis, SMP-H3 (molecular weight of 25.8 × 103 g/mol) exhibited superior anti-inflammatory properties compared to SMP-H1 and SMP-H2, demonstrating a significant decrease in NO production. SMP-H3 also demonstrated a remarkable reduction in the secretion of inflammatory mediators including NO, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines including tumour necrosis factor-alpha (TNF-α), interleukin (IL-1β and IL-6), while increasing IL-10 expression. Furthermore, SMP-H3 significantly inhibited LPS-stimulated cluster of differentiation (CD) 11b and CD40 expression. Our subsequent investigation unveiled the involvement of SMP-H3-activated macrophages in the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Additionally, SMP-H3 exhibited antioxidant activity by scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide, and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) free radicals. These findings suggest the potential of SMP-H3 as an ingredient in the development of alternative drugs or functional foods.

Structural and biofunctional diversity of sulfated polysaccharides from the genus Codium (Bryopsidales, Chlorophyta): A review

It is believed that polysaccharides will become a focal point for future production of food, pharmaceuticals, and materials due to their ubiquitous and renewable nature, as well as their exceptional properties that have been extensively validated in the fields of nutrition, healthcare, and materials. Sulfated polysaccharides derived from seaweed sources have attracted considerable attention owing to their distinctive structures and properties. The genus Codium, represented by the species C. fragile, holds significance as a vital economic green seaweed and serves as a traditional Chinese medicinal herb. To date, the cell walls of the genus Codium have been found to contain at least four types of sulfated polysaccharides, specifically pyruvylated β-d-galactan sulfates, sulfated arabinogalactans, sulfated β-l-arabinans, and sulfated β-d-mannans. These sulfated polysaccharides exhibit diverse biofunctions, including anticoagulant, immune-enhancing, anticancer, antioxidant activities, and drug-carrying capacity. This review explores the structural and biofunctional diversity of sulfated polysaccharides derived from the genus Codium. Additionally, in addressing the impending challenges within the industrialization of these polysaccharides, encompassing concerns regarding scale-up production and quality control, we outline potential strategies to address these challenges from the perspectives of raw materials, extraction processes, purification technologies, and methods for quality control.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Screening and Characteristics Analysis of Polysaccharides from Orah Mandarin (Citrus reticulata cv. Orah)

This study aimed to screen out polysaccharides with the ability to activate NK cells. Ten polysaccharides (OP) were isolated from orah mandarin (Citrus reticulata cv. Orah) peel using hot-water extraction combined with the alcohol precipitation method and the ultrafiltration-membrane separation method. After measuring the effects of 10 OPs on NK-92MI cell proliferation and cytotoxicity, it was found that the polysaccharide OP5 had the highest activity in vitro. OP5 can significantly promote the proliferation of and increase the gene expression of perforin, granzyme B and IFN-γ in NK-92MI cells. Its molecular weight was between 50 and 70 kDa. The identification results of monosaccharide composition indicated that OP5 was composed of arabinose (31.52%), galacturonic acid (22.35%), galactose (16.72%), glucose (15.95%), mannose (7.67%), rhamnose (2.39%), fucose (1.41%), xylose (1.30%), glucuronic acid (0.42%) and ribose (0.27%). The sugar ring of the β-configuration was the main, and that of the α-configuration was the auxiliary. These results would provide a foundation for the functional product development of OPs.

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.

Digestion characteristics of polysaccharides from Gracilaria lemaneiformis and its interaction with the human gut microbiota

The health effects of polysaccharides have attracted lots of attention, but the exact mechanism remains unclear. This study indicated that polysaccharides from Gracilaria lemaneiformis (GLPs) tolerated the conditions of mouth, stomach, and small intestine, and it reached the colon integrally, where it increased the production of short chain fatty acids, altered the gut microbiota, and especially increased the level of Bacteroides. To explore the underlying mechanism, hundreds of Bacteroides strains were isolated from the human feces and identified by MALDI-TOF/MS. It showed that Bacteroides species profile was different between individuals, revealing an inherent difference in the human gut microbiota. The use of Bacteroides on GLPs was species-dependent, and various small molecular GLPs fragments can be liberated from growth of Bacteroides species. On the other hand, Bacteroides species that unable to grow with GLPs can live in GLPs-derived fragments, forming a GLPs utilization network. It should be noted that small molecular GLPs fragments can be easier to be metabolized by intestinal microbes and have better effect on cellular response. It suggested that the effect of polysaccharides cannot only be attributed to modulation of the gut microbiota, but also associated with the effect of microbial degradation on GLPs own activities.

Using metabolomics to discover the immunomodulator activity of food plants

Many edible plants exhibit immunomodulator activities that have beneficial effects on human health. These activities include the ability to activate, multiply, or suppress elements of the immune response. Some of these plants promote health by strengthening host defences against different diseases. In this article, we provide a comprehensive review of the constituents of several edible plants, their immunomodulatory activity, and mechanism of actions for Carica papaya, Coffea sp, Asparagus cochinchinensis, Dioscorea alata, beans, mushrooms, herbs, spices, and several vegetables. The studies reported here are pre-clinical (in vitro and in vivo) and clinical studies (limited in number). The bioactive compounds responsible for the immunomodulator activity of these plants were yet to be identified. This is because the plant is naturally a complex mixture, whilst the immune system is also an intricate system involving many cells and cytokines/chemokines. Metabolomics is a key tool for conducting global profiling of metabolites in a complex system. Therefore, it offers the ability to identify the presence of compounds in plant extracts associated with their immunomodulation effects. Likewise, metabolomics can also be used to detect any changes to metabolites in the cell as a response to treatment. Therefore, affected metabolic pathways that lead to the activation of certain immune responses can be determined from one single experiment. However, we found in this review that the use of a metabolomics approach is not yet fully developed for an immunomodulator study of food plants. This is important for the direction of future research in this field because unlike medicinal plants, food plants are consumed on a regular basis in small amounts with more obvious effects on the immune system. Information about possible bioactive compounds, their interactions (synergism, antagonism), and how the human body responds to them should be studied in a more holistic way.

NMR spectroscopy for structural elucidation of sulfated polysaccharides from red seaweeds

Some sulfated polysaccharides from red seaweeds are used as hydrocolloids. In addition, it is well known that there are sulfated galactans (carrageenans and agarans) and sulfated mannans, with remarkable biological properties, as antiviral, antitumoral, immunomodulating, antiangiogenic, antioxidant, anticoagulant, and antithrombotic activities, and so on. Knowledge of the detailed structure of the active compound is essential and difficult to acquire. The substitution patterns of the polymer chain, as degree of sulfation and position of sulfate groups, as well as other substituents of the backbone, determine their biological behavior. NMR spectroscopy is a powerful and versatile tool for structural determination. It can be used for elucidation of structures of polysaccharides from new algal sources with novel substitutions or to detect the already known structures from different algal sources, and it could even help to monitor the quality of the active compound on a productive scale. In this review, the available information about NMR spectroscopy of sulfated polysaccharides from red seaweeds is revised and rationalized, to help other researchers working in different fields to study their structures. In addition, considerations about the effects of different structural features, as well as some recording conditions on the chemical shifts of the signals are analyzed.

Understanding immune-modulatory efficacy in vitro

Boosting or suppressing our immune system represents an attractive adjunct in the treatment of infections including SARS-CoV-2, cancer, AIDS, malnutrition, age related problems and some inflammatory disorders. Thus, there has been a growing interest in exploring and developing novel drugs, natural or synthetic, that can manipulate our defence mechanism. Many of such studies, reported till date, have been designed to explore effect of the therapeutic on function of macrophages, being a key component in innate immune system. Indeed, RAW264.7, J774A.1, THP-1 and U937 cell lines act as ideal model systems for preliminary investigation and selection of dose for in vivo studies. Several bioassays have been standardized so far where many techniques require high throughput instruments, cost effective reagents and technical assistance that may hinder many scholars to perform a method demanding compilation of available protocols. In this review, we have taken an attempt for the first time to congregate commonly used in vitro immune-modulating techniques explaining their principles. The study detected that among about 40 different assays and more than 150 sets of primers, the methods of cell proliferation by MTT, phagocytosis by neutral red, NO detection by Griess reaction and estimation of expression of TLRs, COX-2, iNOS, TNF-α, IL-6 and IL-1β by PCR have been the most widely used to screen the therapeutics under investigation.

Advance research in biomedical applications on marine sulfated polysaccharide

Marine ecosystem associated organisms are an affluent source of bioactive compounds. Polysaccharides with unique structural and practical entities have gained special studies interest inside the current biomedical zone. Polysaccharides are the main components of marine algae, plants, animals, insects, and microorganisms. In recent times research on seaweed is more persistent for extraction of natural bioactive "Sulfated polysaccharides" (SPs). The considerable amount of SP exists in the algae in the form of fucans, fucoidans, carrageenans, ulvan, etc. Major function of SPs is to act as a defensive lattice towards the infective organism. All SPs possess the high potential and possess a broad range of therapeutic applications as antitumor, immunomodulatory, vaccine adjuvant, anti-inflammatory, anticoagulant, antiviral, antiprotozoal, antimicrobial, antilipemic, therapy of regenerative medicine, also in drug delivery and tissue engineering application. This review aims to discuss the biomedicine applications of sulfated polysaccharides from marine seaweeds.

Evaluation of the Potential of Marine Algae Extracts as a Source of Functional Ingredients Using Zebrafish as Animal Model for Aquaculture

Research on immunotherapeutic agents has become a focus for the treatment of fish diseases. The ability of algae to produce secondary metabolites of potential interest as immunotherapeutics has been documented. The present research intended to assess antiviral and antibacterial activities of macro- and microalgae extracts against viral and bacterial pathogens and explore their immunomodulatory potential using zebrafish (Danio rerio) larvae as a model organism. The cytotoxicity and antiviral activity of eight methanolic and ethanolic extracts from two macroalgae (Fucus vesiculosus, Ulva rigida) and two microalgae (Nannochloropsis gaditana, Chlorella sp.) were analyzed in established fish cell lines. Six extracts were selected to evaluate antibacterial activity by disk diffusion and growth inhibition assays. The three most promising extracts were characterized in terms of fatty acid composition, incorporated at 1% into a plant-based diet, and evaluated their effect on zebrafish immune response and intestinal morphology in a short-term feeding trial. All extracts exhibited in vitro antiviral activity against viral hemorrhagic septicemia and/or infectious pancreatic necrosis viruses. Methanolic extracts from F. vesiculosus and U. rigida were richer in saturated fatty acids and exhibited in vitro antibacterial action against several bacteria. Most promising results were obtained in vivo with F. vesiculosus methanol extract, which exerted an anti-inflammatory action when incorporated alone into diets and induced pro-inflammatory cytokine expression, when combined with the other extracts. Moreover, dietary inclusion of the extracts improved intestinal morphology. In summary, the results obtained in this study support the potential of algae as natural sources of bioactive compounds for the aquaculture industry.

Transcriptome Analysis Reveals Possible Immunomodulatory Activity Mechanism of Chlorella sp. Exopolysaccharides on RAW264.7 Macrophages

In this study, the exopolysaccharides of Chlorella sp. (CEP) were isolated to obtain the purified fraction CEP4. Characterization results showed that CEP4 was a sulfated heteropolysaccharide. The main monosaccharide components of CEP4 are glucosamine hydrochloride (40.8%) and glucuronic acid (21.0%). The impact of CEP4 on the immune activity of RAW264.7 macrophage cytokines was detected, and the results showed that CEP4 induced the production of nitric oxide (NO), TNF-α, and IL-6 in a dose-dependent pattern within a range of 6 μg/mL. A total of 4824 differentially expressed genes (DEGs) were obtained from the results of RNA-seq. Gene enrichment analysis showed that immune-related genes such as NFKB1, IL-6, and IL-1β were significantly upregulated, while the genes RIPK1 and TLR4 were significantly downregulated. KEGG pathway enrichment analysis showed that DEGs were significantly enriched in immune-related biological processes, including toll-like receptor (TLR) signaling pathway, cytosolic DNA-sensing pathway, and C-type lectin receptor signaling pathway. Protein–protein interaction (PPI) network analysis showed that HSP90AB1, Rbx1, ISG15, Psmb6, Psmb3, Psmb8, PSMA7, Polr2f, Rpsa, and NEDD8 were the hub genes with an essential role in the immune activity of CEP4. The preliminary results of the present study revealed the potential mechanism of CEP4 in the immune regulation of RAW264.7 macrophages, suggesting that CEP4 is a promising immunoregulatory agent.

The Structural Characteristics of Seaweed Polysaccharides and Their Application in Gel Drug Delivery Systems

In recent years, researchers across various fields have shown a keen interest in the exploitation of biocompatible natural polymer materials, especially the development and application of seaweed polysaccharides. Seaweed polysaccharides are a multi-component mixture composed of one or more monosaccharides, which have the functions of being anti-virus, anti-tumor, anti-mutation, anti-radiation and enhancing immunity. These biological activities allow them to be applied in various controllable and sustained anti-inflammatory and anticancer drug delivery systems, such as seaweed polysaccharide-based nanoparticles, microspheres and gels, etc. This review summarizes the advantages of alginic acid, carrageenan and other seaweed polysaccharides, and focuses on their application in gel drug delivery systems (such as nanogels, microgels and hydrogels). In addition, recent literature reports and applications of seaweed polysaccharides are also discussed.

Dietary supplementation of Ascophylum nodosum improved kidney function of mink challenged with Aleutian mink disease virus

BACKGROUND

Feed additives which can ease the negative effects of infection by the Aleutian mink disease virus (AMDV) are of interest to mink farmers. The effects of kelp meal (Ascophylum nodosum) supplementation on immune response, virus replication and blood parameters of mink inoculated with AMDV were assessed. AMDV-free black mink (n = 75) were intranasally inoculated with a local strain of AMDV and fed a commercial pellet supplemented with kelp meal at the rates of 1.5% or 0.75% of the feed or were kept as controls (no kelp) for 451 days. Blood was collected on days 0 (pre-inoculation), 31, 56, 99, 155, 366 and 451 post-inoculation (dpi).

RESULTS

No significant difference was observed among the treatments for the proportion of animals positive for antibodies against the virus measured by the counter-immunoelectrophoresis (CIEP), viremia measured by PCR, antibody titer measured by quantitative ELISA, total serum protein measured by a refractometer or elevated levels of gamma globulin measured by iodine agglutination test at the sampling occasions. At the termination of the experiment on 451 dpi, there were no differences among treatments for antibody titer measured by CIEP, total serum protein, albumin, globulins, albumin:globulin ratio, alkaline phosphatase, gamma-glutamyl transferase, and proportions of PCR positive spleen, lymph node or bone marrow samples, but blood urea nitrogen and creatine levels were significantly lower in the 1.5% kelp supplemented group than in the controls.

CONCLUSION

Kelp supplementation improved kidney function of mink infected with AMDV with no effect on liver function, immune response to infection by AMDV or virus replication.

Isolation, purification, characterization, and immunomodulatory effects of polysaccharide from Auricularia auricula on RAW264.7 macrophages

Auricularia auricula polysaccharide (AAP) was isolated by hot-water extraction and purified to evaluate its structural and immunomodulatory effects on RAW264.7 macrophages. The results show that three kinds of Auricularia auricula polysaccharides (c-AAP) were obtained and named as AAP-I, AAP-II, and AAP-III Their further purification found that AAP-I and AAP-II were glycoproteins, and only AAP-III was a pure polysaccharide, which we named AAP for further experiments. Structural characteristics revealed that AAP was a homogeneous galactan comprising mannose, rhamnose, gluconic acid, glucose, galactose, arabinose, and fucose in a molar ratio of 5.02:0.9:0.12:4.48:0.37:1.0:0.36, and the average molecular weight is approximately 23.51 kDa. Methylation analysis revealed that AAP mainly consisted of 1,4-linked-Glcp, 1,4,6-linked-Glcp, terminal Glcp, 1,4-linked-Manp, 1,2,6-linked-Manp, and terminal Arap. Furthermore, the in vitro immunomodulatory activities of AAP were evaluated by cell proliferation, NO production, and phagocytic ability using RAW264.7 macrophage cells. The results show that AAP not only promoted the activation of macrophages but also provided a scientific basis for the further use of AAP. PRACTICAL APPLICATIONS: Three water-soluble polysaccharides were extracted from Auricularia auricula of Changbai Mountain, two of which contained binding proteins. Determination of molecular weight, structure, and immunoreactivity of pure polysaccharide components. The result clearly demonstrated the benefits of this plant as a healthy functional food.

The Comparative Immunotropic Activity of Carrageenan, Chitosan and Their Complexes

The immunotropic activity of polyelectrolyte complexes (PEC) of κ-carrageenan (κ-CGN) and chitosan (CH) of various compositions was assessed in comparison with the initial polysaccharides in comparable doses. For this, two soluble forms of PEC, with an excess of CH (CH:CGN mass ratios of 10:1) and with an excess of CGN (CH: CGN mass ratios of 1:10) were prepared. The ability of PEC to scavenge NO depended on the content of the κ-CGN in the PEC. The ability of the PEC to induce the synthesis of pro-inflammatory (tumor necrosis factor-α (TNF-α)) and anti-inflammatory (interleukine-10 (IL-10)) cytokines in peripheral blood mononuclear cell was determined by the activity of the initial κ-CGN, regardless of their composition. The anti-inflammatory activity of PEC and the initial compounds was studied using test of histamine-, concanavalin A-, and sheep erythrocyte immunization-induced inflammation in mice. The highest activity of PEC, as well as the initial polysaccharides κ-CGN and CH, was observed in a histamine-induced exudative inflammation, directly related to the activation of phagocytic cells, i.e., macrophages and neutrophils.

Vaccine Adjuvants Derived from Marine Organisms

Vaccine adjuvants help to enhance the immunogenicity of weak antigens. The adjuvant effect of certain substances was noted long ago (the 40s of the last century), and since then a large number of adjuvants belonging to different groups of chemicals have been studied. This review presents research data on the nonspecific action of substances originated from marine organisms, their derivatives and complexes, united by the name 'adjuvants'. There are covered the mechanisms of their action, safety, as well as the practical use of adjuvants derived from marine hydrobionts in medical immunology and veterinary medicine to create modern vaccines that should be non-toxic and efficient. The present review is intended to briefly describe some important achievements in the use of marine resources to solve this important problem.

Pharmacologic Application Potentials of Sulfated Polysaccharide from Marine Algae

With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to the isolation of active compounds with biological activities, such as antioxidation of free radicals, anti-inflammation, antiproliferation of cancer cells, and anticoagulant to name a few. One of the compounds that are isolated from marine algae are sulfated polysaccharides (SPs). SPs are complex heterogenous natural polymers with an abundance found in different species of marine algae. Marine algae are known to be one of the most important sources of SPs, and depending on the species, its chemical structure varies. This variety has important physical and chemical components and functions which has gained the attention of researchers as this contributes to the many facets of its pharmacologic activity. In this review, recent pharmacologic application potentials and updates on the use of SPs from marine algae are discussed.

Caulerpa Cupressoides Var. Flabellata

Green seaweeds are rich sources of sulfated polysaccharides (SPs) with potential biomedical and nutraceutical applications. The aim of this work was to evaluate the immunostimulatory activity of SPs from the seaweed, Caulerpa cupressoides var. flabellata on murine RAW 264.7 macrophages. SPs were evaluated for their ability to modify cell viability and to stimulate the production of inflammatory mediators, such as nitric oxide (NO), intracellular reactive oxygen species (ROS), and cytokines. Additionally, their effect on inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) gene expression was investigated. The results showed that SPs were not cytotoxic and were able to increase in the production of NO, ROS and the cytokines, tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). It was also observed that treatment with SPs increased iNOS and COX-2 gene expression. Together, these results indicate that C. cupressoides var. flabellata SPs have strong immunostimulatory activity, with potential biomedical applications.

Partial Characterization, the Immune Modulation and Anticancer Activities of Sulfated Polysaccharides from Filamentous Microalgae Tribonema sp

Recently, Tribonema sp., a kind of filamentous microalgae, has been studied for biofuel production due to its accumulation of triacylglycerols. However, the polysaccharides of Tribonema sp. and their biological activities have rarely been reported. In this paper, we extracted sulfated polysaccharides from Tribonema sp. (TSP), characterized their chemical composition and structure, and determined their immunostimulation and anticancer activities on RAW264.7 macrophage cells and HepG2 cells. The results showed that TSP is a sulfated polysaccharide with a M_w of 197 kDa. TSP is a heteropolysaccharide that is composed mainly of galactose. It showed significant immune-modulatory activity by stimulating macrophage cells, such as upregulating interleukin 6 (IL-6), interleukin 10 (IL-10), and tumor necrosis factor α (TNF-α). In addition, TSP also showed significant dose-dependent anticancer activity (with an inhibition rate of up to 66.8% at 250 µg/mL) on HepG2 cells as determined by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cycle analysis indicated that the anticancer activity of TSP is mainly the result of induced cell apoptosis rather than affecting the cell cycle and mitosis of HepG2 cells. These findings suggest that TSP might have potential as an anticancer resource, but further research is needed, especially in vivo experiments, to explore the anticancer mechanism of TSP.

From Marine Origin to Therapeutics: The Antitumor Potential of Marine Algae-Derived Compounds

Marine environment has demonstrated to be an interesting source of compounds with uncommon and unique chemical features on which the molecular modeling and chemical synthesis of new drugs can be based with greater efficacy and specificity for the therapeutics. Cancer is a growing public health threat, and despite the advances in biomedical research and technology, there is an urgent need for the development of new anticancer drugs. In this field, it is estimated that more than 60% of commercially available anticancer drugs are natural biomimetic inspired. Among the marine organisms, algae have revealed to be one of the major sources of new compounds of marine origin, including those exhibiting antitumor and cytotoxic potential. These compounds demonstrated ability to mediate specific inhibitory activities on a number of key cellular processes, including apoptosis pathways, angiogenesis, migration and invasion, in both in vitro and in vivo models, revealing their potential to be used as anticancer drugs. This review will focus on the bioactive molecules from algae with antitumor potential, from their origin to their potential uses, with special emphasis to the alga Sphaerococcus coronopifolius as a producer of cytotoxic compounds.

Recent Advances in Marine Algae Polysaccharides: Isolation, Structure, and Activities

Marine algae have attracted a great deal of interest as excellent sources of nutrients. Polysaccharides are the main components in marine algae, hence a great deal of attention has been directed at isolation and characterization of marine algae polysaccharides because of their numerous health benefits. In this review, extraction and purification approaches and chemico-physical properties of marine algae polysaccharides (MAPs) are summarized. The biological activities, which include immunomodulatory, antitumor, antiviral, antioxidant, and hypolipidemic, are also discussed. Additionally, structure-function relationships are analyzed and summarized. MAPs' biological activities are closely correlated with their monosaccharide composition, molecular weights, linkage types, and chain conformation. In order to promote further exploitation and utilization of polysaccharides from marine algae for functional food and pharmaceutical areas, high efficiency, and low-cost polysaccharide extraction and purification methods, quality control, structure-function activity relationships, and specific mechanisms of MAPs activation need to be extensively investigated.

Isolation, characterization and bioactivities of the polysaccharides from Dicliptera chinensis (L.) Juss

The polysaccharides of Dicliptera chinensis (L.) Juss. (DCP-1 and DCP-2) were extracted and isolated using the methods of water extract-ethanol precipitate and sephadex column chromatography and characterized by gel permeation chromatography (GPC), Fourier transform infrared spectrometry (FT-IR) and gas chromatography (GC), respectively. The antioxidant activity of DCPs was evaluated by scavenging activity of DPPH, hydroxyl, superoxide anion and ABTS radical. Moreover, the anti-aging activity of DCP-2 was investigated using an aging model-induced by D-galactose (D-gal) in mice. The results show that the weight average molecular weight (Mw) of DCP-2 was 2 273Da with a narrow polydispersity index of 1.01, and it was a heteropolysaccharide and consisted of glucose, galactose, arabinose, rhamnose and mannose with a molar ratio of 3.20:2.54:1.69:1.58:1.00. DCP-2 had stronger antioxidant activity against DPPH, hydroxyl, superoxide anion and ABTS radical, while DCP-1 had hardly any antioxidant activity and DCP had weaker antioxidant activity. Furthermore, DCP-2 can enhance antioxidant capacity and had anti-aging activity against D-gal induced aging mice. These results proposed that DCP-2 might be developed as a potential functional food with the activity of anti-aging.

Application of seaweeds to develop new food products with enhanced shelf-life, quality and health-related beneficial properties

Edible seaweeds are a good source of antioxidants, dietary fibers, essential amino acids, vitamins, phytochemicals, polyunsaturated fatty acids, and minerals. Many studies have evaluated the gelling, thickening and therapeutic properties of seaweeds when they are used individually. This review gives an overview on the nutritional, textural, sensorial, and health-related properties of food products enriched with seaweeds and seaweed extracts. The effect of seaweed incorporation on properties of meat, fish, bakery, and other food products were highlighted in depth. Moreover, the positive effects of foods enriched with seaweeds and seaweed extracts on different lifestyle diseases such as obesity, dyslipidemia, hypertension, and diabetes were also discussed. The results of the studies demonstrated that the addition of seaweeds, in powder or extract form, can improve the nutritional and textural properties of food products. Additionally, low-fat products with less calories and less saturated fatty acids can be prepared using seaweeds. Moreover, the addition of seaweeds also affected the health properties of food products. The results of these studies demonstrated that the health value, shelf-life and overall quality of foods can be improved through the addition of either seaweeds or seaweed extracts.

Proteins and Carbohydrates from Red Seaweeds: Evidence for Beneficial Effects on Gut Function and Microbiota

Based on their composition, marine algae, and namely red seaweeds, are good potential functional foods. Intestinal mucosal barrier function refers to the capacity of the intestine to provide adequate containment of luminal microorganisms and molecules. Here, we will first outline the component of seaweeds and will summarize the effects of these on the regulation of mucosal barrier function. Special attention will be paid to unique components of red seaweeds: proteins and derived peptides (e.g., phycobiliproteins, glycoproteins that contain “cellulose binding domains”, phycolectins and the related mycosporine-like amino acids) together with polysaccharides (e.g., floridean starch and sulfated galactans, such as carrageenans, agarans and “dl-hybrid”) and minerals. These compounds have been shown to exert prebiotic effects, to regulate intestinal epithelial cell, macrophage and lymphocyte proliferation and differentiation and to modulate the immune response. Molecular mechanisms of action of peptides and polysaccharides are starting to be elucidated, and evidence indicating the involvement of epidermal growth factor receptor (EGFR), insulin-like growth factor receptor (IGFR), Toll-like receptors (TLR) and signal transduction pathways mediated by protein kinase B (PKB or AKT), nuclear factor-κB (NF-κB) and mitogen activated protein kinases (MAPK) will also be summarized. The need for further research is clear, but in vivo experiments point to an overall antiinflammatory effect of these algae, indicating that they can reinforce membrane barrier function.