Chemical properties and toxicology studies of fucoidan extracted from Malaysian Sargassum binderi

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

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

Purification and Structural Characterization of Sulfated Polysaccharides Derived from Brown Algae, Sargassum binderi: Inhibitory Mechanism of iNOS and COX-2 Pathway Interaction

Among the components derived from brown algae, anionic sulfated polysaccharides, which contain sulfated fucose as the major monosaccharide, exert significant biological activities. In this study, we purified and structurally characterized sulfated polysaccharides from brown algae, Sargassum binderi (S. binderi; SBPs), and evaluated their biological activity in vitro and in vivo. The SBPs were separated based on their charges and their biophysical properties were investigated according to their functional groups, structural features, and molecular weights using FTIR, NMR, and MALS. Among all the SBPs, Fraction 4 (SBP-F4), with an average molecular weight of 2.867 × 10⁵ g/mol, had the highest polysaccharide and sulfate contents (75.15 ± 0.25% and 24.08 ± 0.18%, respectively). The biological activities of SBP-F4 were investigated further in vitro and in vivo. Our results showed that SBP-F4 significantly suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins in LPS-activated macrophages. Moreover, in the LPS-treated zebrafish model, a significant decrease in cell death and NO production was observed. Collectively, these results show that SBPs not only exert protective effects against LPS-induced cytotoxicity but also inhibit the activation and anti-inflammatory activity of macrophages. Therefore, polysaccharides derived from S. binderi are potential anti-inflammatory agents for use in clinical settings.

The role of algal fucoidans in potential anti-allergic therapeutics

Allergic diseases are among the commonest causes of chronic ill-health and are rapidly rising the prevalence and complexity. Although the current drugs are efficacy for treatment of allergic diseases, however the extensive clinical use of these drugs has led to the diverse and undesirable side effects. Thus, the extensive studies of alternative anti-allergic agents from natural products are essential for a long-term purpose. Marine environment covers a huge source of extremely potential secondary metabolites for drug discovery. Among them, fucoidans from brown seaweeds have been evidenced to possess various biological activities and health benefit effects. Notably, a great deal of interest has been expressed regarding anti-allergic activity of fucoidans. Consequently, this contribution presents an overview of potential anti-allergic therapeutics of fucoidans from brown seaweeds to emphasize its functions in prevention as well as treatment of allergic diseases.

A Critical Review of the Abilities, Determinants, and Possible Molecular Mechanisms of Seaweed Polysaccharides Antioxidants

Oxidative stress induces various cardiovascular, neurodegenerative, and cancer diseases, caused by excess reactive oxygen species (ROS). It is attributed to the lack of sufficient antioxidant defense capacity to eliminate unnecessary ROS. Seaweeds are largely cultivated for their edible and commercial purposes. Excessive proliferation of some seaweeds has occurred in coastal areas, causing environmental and economic disasters, and even threating human health. Removing and disposing of the excess seaweeds are costly and labor-intensive with few rewards. Therefore, improving the value of seaweeds utilizes this resource, but also deals with the accumulated biomass in the environment. Seaweed has been demonstrated to be a great source of polysaccharides antioxidants, which are effective in enhancing the antioxidant system in humans and animals. They have been reported to be a healthful method to prevent and/or reduce oxidative damage. Current studies indicate that they have a good potential for treating various diseases. Polysaccharides, the main components in seaweeds, are commonly used as industrial feedstock. They are readily extracted by aqueous and acetone solutions. This study attempts to review the current researches related to seaweed polysaccharides as an antioxidant. We discuss the main categories, their antioxidant abilities, their determinants, and their possible molecular mechanisms of action. This review proposes possible high-value ways to utilize seaweed resources.

Haimufang decoction, a Chinese medicine formula for lung cancer, arrests cell cycle, stimulates apoptosis in NCI-H1975 cells, and induces M1 polarization in RAW 264.7 macrophage cells

BACKGROUND

Lung cancer has the highest morbidity and mortality in the world and novel treatment strategies are still needed. Haimufang decoction (HMF) is a patented clinical prescription of traditional Chinese medicine for lung cancer treatment. HMF is composed of four herbs and has been applied clinically in advanced cancer patients. However, its therapeutic mechanisms are still unclear. This study aims to elucidate the possible mechanisms of HMF for the treatment of lung cancer.

METHODS

3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay was applied for evaluating the proliferative effect of HMF in lung cancer cells and monocyte macrophage RAW264.7 cells. Flow cytometer was used to detect the effects of HMF on cell cycle and apoptosis, and western blotting was employed to explore the potential apoptotic mechanisms of HMF on lung cancer cells. For immunomodulatory effect, co-culture system was used to detect the activation of macrophage RAW264.7 cells when treated with HMF, and neutral red assay was used to measure the effect of HMF on the phagocytosis of the activated macrophages. Enzyme linked immunosorbent assay, flow cytometer, and immunofluorescence staining method were employed for the investigation on the underlying mechanisms of the immunomodulatory effect on RAW264.7 induced by HMF.

RESULTS

HMF inhibited the proliferation, induced S phase cell cycle arrest, and stimulated apoptosis in lung cancer NCI-H1975 cells, while had negligible cytotoxicity on macrophage RAW264.7 cells. Moreover, HMF could activate macrophage RAW264.7 cells and promote the inhibition activity of RAW264.7 cells against lung cancer cells. And also, HMF activated macrophages and increased their phagocytic activity in a concentration-dependent manner. HMF increased the expression of macrophage activation marker CD40, the level of nitric oxide, the generation of intracellular reactive oxygen species, as well as M1 macrophages cytokines including tumor necrosis factor-α, interleukin-1β, interleukin 12 p70, and interleukin 6. Further investigation showed that HMF induced M1 but not M2 phenotype polarization in RAW264.7 cells.

CONCLUSIONS

HMF can mainly exert anticancer activity via (1) cytotoxicity to human lung cancer cells by proliferation inhibition, cell cycle arrest, and apoptosis induction; and also via (2) immunomodulation via macrophage cells activation and M1 phenotype polarization induction.

Advanced Technologies for the Extraction of Marine Brown Algal Polysaccharides

Over the years, brown algae bioactive polysaccharides laminarin, alginate and fucoidan have been isolated and used in functional foods, cosmeceutical and pharmaceutical industries. The extraction process of these polysaccharides includes several complex and time-consuming steps and the correct adjustment of extraction parameters (e.g., time, temperature, power, pressure, solvent and sample to solvent ratio) greatly influences the yield, physical, chemical and biochemical properties as well as their biological activities. This review includes the most recent conventional procedures for brown algae polysaccharides extraction along with advanced extraction techniques (microwave-assisted extraction, ultrasound assisted extraction, pressurized liquid extraction and enzymes assisted extraction) which can effectively improve extraction process. The influence of these extraction techniques and their individual parameters on yield, chemical structure and biological activities from the most current literature is discussed, along with their potential for commercial applications as bioactive compounds and drug delivery systems.

Extraction and Modification of Macroalgal Polysaccharides for Current and Next-Generation Applications

Marine macroalgal (seaweed) polysaccharides are highly promising for next-generation applications in several industries. However, despite the reported comprehensive potential of these polysaccharides, commercial products are scarce on the market. Seaweed cultivations are increasing in number and production quantity, owing to an elevated global trend of utilization interest in seaweed. The extraction of polysaccharides from seaweed generally generates low yields, but novel methods are being developed to facilitate and improve the extraction processes. Current areas of applications for seaweed polysaccharides mainly take advantage of the physicochemical properties of certain polysaccharides, such as gelling, thickening and emulsifying. However, many of the numerous bioactivities reported are still only at research level and lack clinical evidence for commercialization. It has been suggested the construction of smaller units may generate better defined molecules that are more suitable for biomedical applications. Enzymatic modification is a promising tool for the generation of more defined, targeted biomolecules. This review covers; structural differences between the most predominant marine algal polysaccharides, extraction processes, modification alternatives, as well as a summary of current and potential next-generation application areas.