Structural characterization and antagonistic effect against P-selectin-mediated function of SFF-32, a fucoidan fraction from Sargassum fusiforme

Inhibition of Norovirus GII.4 binding to HBGAs by Sargassum fusiforme polysaccharide

Norovirus (NoV) is the main pathogen that causes acute gastroenteritis and brings a heavy socio-economic burden worldwide. In this study, five polysaccharide fractions, labeled pSFP-1-5, were isolated and purified from Sargassum fusiforme (S. fusiforme). In vitro experiments demonstrated that pSFP-5 significantly prevented the binding of type A, B and H histo-blood group antigens (HBGAs) to NoV GII.4 virus-like particles (NoV GII.4 VLPs). In addition, in vivo experiments revealed that pSFP-5 was effective in reducing the accumulation of NoV in oysters, indicating that pSFP-5 could reduce the risk of NoV infection from oyster consumption. The results of transmission electron microscopy showed that the appearance of NoV GII.4 VLPs changed after pSFP-5 treatment, indicating that pSFP-5 may achieve antiviral ability by altering the morphological structure of the viral particles so that they could not bind to HBGAs. The results of the present study indicate that pSFP-5 may be an effective anti-NoV substance and can be used as a potential anti-NoV drug component.

Structural characterization and immune-enhancing effects of a novel polysaccharide extracted from Sargassum fusiforme

To alleviate the adverse effects of chemotherapy and bolster immune function, a novel polysaccharide derived from Sargassum fusiforme named as SFP-αII. The structural composition of SFP-αII predominantly consisted of guluronic and mannuronic acids in a molar ratio of 33.8:66.2, with an average molecular weight of 16.5 kDa. Its structure was primarily characterized by →4)-α-GulA-(1 → and →4)-β-ManA-(1 → linkages confirmed by FT-IR, methylation, and NMR analyses. The absence of a triple-helix structure was in SFP-αII was confirmed using circular dichroism and Congo red dye assays. The dimensions varied with lengths ranging from 20 nm up to 3 μm revealed by atomic force microscopy (AFM). SFP-αII has been found to enhance immunomodulatory activity in cyclophosphamide (CTX)-induced immunosuppressed mice. This was evidenced by improvements in immune organ indices, cytokine levels, and the release of nitric oxide (NO). Specifically, SFP-αII mitigated immunosuppression by upregulating the secretion of IL-1β (167.3 %) and TNF-α (227.1 %) at a dose of 400 mg/kg, compared with the CTX group in macrophages. Ultimately, SFP-αII may serve as a mechanism for immune enhancement through modulation of TLR4-mediated NF-κB and MAPK signaling pathways. This integration of traditional Chinese and Western medicine, leveraging SFP-αII as a potential functional food could be pivotal in alleviating immunosuppressive side effects in CTX treatment.

Bioactivities of the Popular Edible Brown Seaweed Sargassum fusiforme: A Review

Sargassum fusiforme has a wide range of active constituents (such as polysaccharides, sterols, polyphenols, terpenes, amino acids, trace elements, etc.) and is an economically important brown algae with a long history. In recent years, S. fusiforme has been intensively studied and has attracted wide attention in the fields of agriculture, environment, medicine, and functional food. In this review, we reviewed the current research status of S. fusiforme at home and abroad over the past decade by searching Web of science, Google Scholar, and other databases, and structurally analyzed the active components of S. fusiforme, and on this basis, we focused on summarizing the cutting-edge research and scientific issues on the role of various active substances in S. fusiforme in exerting antioxidant, anti-inflammatory, antitumor, antidiabetic, immunomodulatory, antiviral antibacterial, and anticoagulant effects. The mechanisms by which different substances exert active effects were further summarized by exploring different experimental models and are shown visually. It provides a reference to promote further development and comprehensive utilization of S. fusiforme resources.

Oligomer-guided recognition of two fucan sulfate from Bohadschia argus and inhibition of P-selectin binding to its ligand

Fucan sulfate (FS) from sea cucumber shows intriguing structure and extensive activities. Here, three homogeneous FS (BaFSI - III) were obtained from Bohadschia argus, followed with physicochemical properties analyses including monosaccharide composition, molecular weight, and sulfate content. BaFSI was proposed to carry a unique distribution pattern of sulfate groups as a novel sequence composed of domain A and domain B that formed by different Fuc_S residues, markedly differing from FS reported before, according to the analyses of 12 oligosaccharides and a representative residual saccharide chain. BaFSII possessed a highly regular structure {4-L-Fuc_3S-α1,}_n according to its peroxide depolymerized product. BaFSIII was confirmed as a FS mixture bearing similar structural characteristics with BaFSI and BaFSII by means of mild acid hydrolysis and oligosaccharide analysis. Bioactivity assays showed that BaFSI and BaFSII could potently inhibit P-selectin binding to PSGL-1 and HL-60 cells. Structure-activity relationship analysis showed that molecular weight and sulfation pattern were the essential factors for the potent inhibition. Meanwhile, an acid hydrolysate of BaFSII with a molecular weight about 15 kDa exhibited a comparable inhibition with the native BaFSII. Given the potent activity and highly regular structure of BaFSII, it shows great potential for development as a P-selectin inhibitor.

Polysaccharide extracted from the Sargassum fusiforme induces cell cycle arrest and apoptosis of B16F10 melanoma cells through the PI3K/AKT pathway

BACKGROUND

SARGASSUM FUSIFORME: (S. fusiforme) is a brown alga that has been utilized as a medicine for a long time. Polysaccharides extracted from S. fusiforme demonstrate antitumor activities.

METHODS

The impact of S. fusiforme polysaccharides (SFPS 191,212) on the proliferation, apoptosis, and cell cycle kinetics of B16F10 murine melanoma cells were thoroughly investigated in this work. The anticancer activities of the SFPS 191,212 compounds were assayed in the B16F10 cells at both transcriptional and translational levels.

RESULTS

The compound exhibited concentration-dependent effects. Moreover, SPFS 191,212 increased the numbers of apoptotic cells and arrested the cell cycle in the S phase of the quantitative real-time PCR. From western blotting, it was verified that the SFPS 191,212 treatment improved the expression of Bax, Caspase-9, and Caspase-3 genes and proteins, while it reduced phosphatidylinositol 3 kinase and Bcl-2 genes and proteins, suggesting the involvement of mitochondria.

CONCLUSION

Overall, SFPS 191,212 can be further explored as a potential functional food or adjuvant agent for the prevention or treatment of melanoma.

A novel galactoxylan derived from Viola diffusa alleviates LPS-induced acute lung injury via antagonizing P-selectin-mediated adhesion function

Acute lung injury (ALI) greatly threatens human health worldwide. P-selectin is a potential target for the treatment of acute inflammatory diseases, and natural polysaccharides exhibit high-affinity for P-selectin. Viola diffusa, a traditional Chinese herbal, shows strong anti-inflammatory effects, but pharmacodynamic substances and underlying mechanisms are still unclear. In this study, a galactoxylan polysaccharide (VDPS) derived from Viola diffusa was isolated and characterized, evaluated the protective effect on LPS induced ALI and underlying mechanism. VDPS significantly alleviated LPS-induced pathological lung injury, and decreased the numbers of total cells and neutrophils as well as the total protein contents in the bronchoalveolar lavage fluid (BALF). Moreover, VDPS reduced proinflammatory cytokine production both in BALF and lung. Interestingly, VDPS significantly restrained the activation of NF-κB signaling in the lung of LPS-exposed mice, but it cannot inhibit LPS-induced inflammation in human pulmonary microvascular endothelial cells (HPMECs) in vitro. Additionally, VDPS disrupted neutrophil adhesion and rolling on the activated HPMECs. VDPS cannot impact the expression or cytomembrane translocation of endothelial P-selectin, but remarkably interrupt the binding of P-selectin and PSGL-1. Overall, this study demonstrated that VDPS can alleviate LPS-induced ALI via inhibiting P-selectin-dependent adhesion and recruitment of neutrophils on the activated endothelium, providing a potential treatment strategy for ALI.

Anti-Leukemia Activity of Polysaccharide from Sargassum fusiforme via the PI3K/AKT/BAD Pathway In Vivo and In Vitro

Studies have shown that Sargassum fusiforme and its extracts are effective herbal treatments for leukemia. We previously found that a polysaccharide from Sargassum fusiforme, SFP 2205, stimulated apoptosis in human erythroleukemia (HEL) cells. However, the structural characterization and antitumoral mechanisms of SFP 2205 remain uncertain. Here, we studied the structural characteristics and anticancer mechanisms of SFP 2205 in HEL cells and a xenograft mouse model. The results demonstrated that SFP 2205, with a molecular weight of 41.85 kDa, consists of mannose, rhamnose, galactose, xylose, glucose, and fucose with monosaccharides composition of 14.2%, 9.4%, 11.8%, 13.7%, 11.0%, and 38.3%, respectively. On animal assays, SFP 2205 significantly inhibited growth of HEL tumor xenografts with no discernible toxicity to normal tissues. Western blotting showed that SFP 2205 therapy improved Bad, Caspase-9, and Caspase-3 protein expression, and ultimately induced HEL tumor apoptosis, indicating mitochondrial pathway involvement. Furthermore, SFP 2205 blocked the PI3K/AKT signaling pathway and 740 Y-P, an activator of the PI3K/AKT pathway, rescued the effects of SFP 2205 on HEL cell proliferation and apoptosis. Overall, SFP 2205 may be a potential functional food additive or adjuvant for preventing or treating leukemia.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

The anti-inflammatory action of fucoidans is well known, based on both in vitro and some in vivo studies. The other biological properties of these compounds, their lack of toxicity, and the possibility of obtaining them from a widely distributed and renewable source, makes them attractive novel bioactives. However, fucoidans’ heterogeneity and variability in composition, structure, and properties depending on seaweed species, biotic and abiotic factors and processing conditions, especially during extraction and purification stages, make it difficult for standardization. A review of the available technologies, including those based on intensification strategies, and their influence on fucoidan composition, structure, and anti-inflammatory potential of crude extracts and fractions is presented.