Low Molecular Weight, 4-O-Sulfation, and Sulfation at Meta-Fucose Positively Promote the Activities of Sea Cucumber Fucoidans on Improving Insulin Resistance in HFD-Fed Mice

Investigation on the mechanism of anionic polysaccharides affecting the gastrointestinal digestion fate of sea cucumber collagen fibrils

Previous research has demonstrated that fucosylated chondroitin sulfate (fCS) and fucoidan (FUC) enhance the gastrointestinal digestion of sea cucumber collagen fibrils, whereas kappa-carrageenan (K-car) and sodium alginate (SA) exhibit inhibitory effects. The objective of this study was to investigate the mechanisms by which these anionic polysaccharides modulate collagen fibril digestion. Upon the addition of fCS and FUC, the total hydroxyproline content in the insoluble precipitate was significantly reduced by 73.98% and 63.62%, respectively, after 2 h of gastric digestion. All four anionic polysaccharides were found to interact with the soluble digestion products of collagen fibrils, leading to fluorescence quenching. Notably, fCS and FUC displayed significantly stronger interactions with the digestion products compared to K-car and SA, as evidenced by fluorescence spectroscopy. Furthermore, heat treatment resulted in enhanced adsorption of polysaccharides onto the insoluble digestion products of collagen fibrils. Interestingly, the inclusion of polysaccharides, particularly fCS and FUC, substantially increased the turbidity of intestinal digestion products. These interactions were mediated by specific collagen, such as APA22677.1, PIK60696.1, PIK60691.1, PIK60692.1, PIK60693.1, and AYL88761.1 (NCBI). These findings provide crucial insights into how anionic polysaccharides influence the digestive behavior of collagen fibrils, offering potential applications in food science and nutrition.

An overview of fucoidan electrospun nanofibers: Fabrication, modification, characterizations and applications

Nanofibers provide tunable attributes which make them promising for various applications. The electrospinning technique provides nanofibers with a large surface area and eases functionalization for various food and pharmaceutical applications. Numerous biopolymers have been employed to produce nanofibers due to their biocompatibility, biodegradability, and absorbability. Among different biopolymers, algal polysaccharides have gained much attention. Fucoidan is a sulfated polysaccharide isolated from brown macroalgae with a broad range of biological properties; therefore, it is highly investigated as a functional and therapeutic agent in foods and pharmaceuticals. Thus, different chemical modifications, such as depolymerization, oversulfation, phosphorylation, amination, acetylation, and benzoylation, or conjugation and functionalization with other polymers, have been used to make them desirable for target applications. The present study comprehensively reviews the electrospinning technique, applications, and crosslinking methods, then highlights the fucoidan attributes, fabrication of fucoidan-based electrospun nanofibers, their properties and functionality for food and biomedical applications.

The therapeutic effects of marine sulfated polysaccharides on diabetic nephropathy

Marine sulfated polysaccharide (MSP) is a natural high molecular polysaccharide containing sulfate groups, which widely exists in various marine organisms. The sources determine structural variabilities of MSPs which have high security and wide biological activities, such as anticoagulation, antitumor, antivirus, immune regulation, regulation of glucose and lipid metabolism, antioxidant, etc. Due to the structural similarities between MSP and endogenous heparan sulfate, a majority of studies have shown that MSP can be used to treat diabetic nephropathy (DN) in vivo and in vitro. In this paper, we reviewed the anti-DN activities, the dominant mechanisms and structure-activity relationship of MSPs in order to provide the overall scene of MSPs as a modality of treating DN.

Potential Application of Marine Fucosyl-Polysaccharides in Regulating Blood Glucose and Hyperglycemic Complications

Diabetes mellitus (DM) has become the world's third major disease after tumors and cardiovascular disease. With the exploitation of marine biological resources, the efficacy of using polysaccharides isolated from marine organisms in blood glucose regulation has received widespread attention. Some marine polysaccharides can reduce blood glucose by inhibiting digestive enzyme activity, eliminating insulin resistance, and regulating gut microbiota. These polysaccharides are mainly fucose-containing sulphated polysaccharides from algae and sea cucumbers. It follows that the hypoglycemic activity of marine fucosyl-polysaccharides is closely related to their structure, such as their sulfate group, monosaccharide composition, molecular weight and glycosidic bond type. However, the structure of marine fucosyl-polysaccharides and the mechanism of their hypoglycemic activity are not yet clear. Therefore, this review comprehensively covers the effects of marine fucosyl-polysaccharides sources, mechanisms and the structure-activity relationship on hypoglycemic activity. Moreover, the potential regulatory effects of fucosyl-polysaccharides on vascular complications caused by hyperglycemia are also summarized in this review. This review provides rationales for the activity study of marine fucosyl-polysaccharides and new insights into the high-value utilization of marine biological resources.