Structural Characterization and α-Glucosidase Inhibitory and Antioxidant Activities of Fucoidans Extracted from Saccharina japonica

Fucoidan-hybrid hydroxyapatite nanoparticles promote the osteogenic differentiation of human periodontal ligament stem cells under inflammatory condition

Inflammation-related bone defects often lead to poor osteogenesis. Therefore, it is crucial to reduce the inflammation response and promote the osteogenic differentiation of stem/progenitor cells to revitalize bone physiology. Here, a kind of hybrid nano-hydroxyapatite was prepared using the confined phosphate ion release method with the participation of fucoidan, a marine-sourced polysaccharide with anti-inflammation property. The physicochemical analyses confirmed that the fucoidan hybrid nano-hydroxyapatite (FC/n-HA) showed fine needle-like architectures. With a higher amount of fucoidan, the crystal size and crystallinity of the FC/n-HA reduced while the liquid dispersibility was improved. Cell experiences showed that FC/n-HA had an optimal cytocompatibility at concentration of 50 μg/mL. Moreover, the lipopolysaccharide-induced cellular inflammatory model with PDLSCs was established and used to evaluate the anti-inflammatory and osteogenic properties. For the 1%FC/n-HA group, the expression levels of TNF-α and IL-1β were significantly reduced at 24 h, while the expression of alkaline phosphatase of PDLSCs was significantly promoted at days 3 and 7, and calcium precipitates was enhanced at 21 days. In this study, the FC/n-HA particles showed effective anti-inflammatory properties and facilitated osteogenic differentiation of PDLSCs, indicating which has potential application in treating bone defects associated with inflammation, such as periodontitis.

Effect of UV-A Irradiation on Bioactive Compounds Accumulation and Hypoglycemia-Related Enzymes Activities of Broccoli and Radish Sprouts

In the present study, different intensities of UV-A were applied to compare their effects on growth, bioactive compounds and hypoglycemia-related enzyme activities in broccoli and radish sprouts. The growth of sprouts was decreased after UV-A irradiation. A total of 12 W of UV-A irradiation resulted in the highest content of anthocyanin, chlorophyll, polyphenol and ascorbic acid in broccoli and radish sprouts. The highest soluble sugar content was recorded in sprouts under 8 W of UV-A irradiation, while no significant difference was obtained in soluble protein content among different UV-A intensities. Furthermore, 12 W of UV-A irradiation induced the highest glucosinolate accumulation, especially glucoraphanin and glucoraphenin in broccoli and radish sprouts, respectively; thus, it enhanced sulforaphane and sulforaphene formation. The α-amylase, α-glucosidase and pancrelipase inhibitory rates of two kinds of sprouts were enhanced significantly after UV-A irradiation, indicating UV-A-irradiation-treated broccoli and radish sprouts have new prospects as hypoglycemic functional foods.

Characterization of an endo-1,3-fucanase from marine bacterium Wenyingzhuangia aestuarii: The first member of a novel glycoside hydrolase family GH174

Sulfated fucans are important marine polysaccharides with various biological and biomedical activities. Fucanases are favorable tools to establish the structure-activity relationships of sulfated fucans. Herein, gene fun174A was discovered from the genome of marine bacterium Wenyingzhuangia aestuarii OF219, and none of the pre-defined glycosidic hydrolase domains were predicted in the protein sequence of Fun174A. Recombinant Fun174A demonstrated a low optimal reaction pH at 5.5. It might degrade sulfated fucans in an endo-processive manner. Glycomics and NMR analyses proved that it specifically hydrolyzed α-1,3-l-fucoside bonds between 2-O-sulfated and non-sulfated fucose residues in the sulfated fucan from sea cucumber Isostichopus badionotus. D119, E120 and E218 were critical for the activity of Fun174A, as identified by site-directed mutagenesis. Three homologs of Fun174A were confirmed to exhibit endo-1,3-fucanase activities. The novelty on sequences of Fun174A and its homologs reveals a new glycoside hydrolase family, GH174.

Saccharina japonica fucan suppresses high fat diet-induced obesity and enriches fucoidan-degrading gut bacteria

Low molecular weight seaweed polysaccharides exhibit promising potential as novel therapeutics for the prevention of obesity and gut microbiota dysbiosis. The interplay between polysaccharides and gut microbiota may play crucial roles in their anti-obesity effects, but is largely unknown, including the impact of polysaccharides on the composition of the gut microbiota with polysaccharide-degrading capacity. The primary structure of a 5.1 kDa fucan (J2H) from Saccharina japonica was characterized and oral administration of J2H effectively suppressed high-fat diet-induced obesity, blood glucose metabolic dysfunction, dyslipidemia, and gut microbiota dysbiosis. Furthermore, the Jensen-Shannon divergence analysis demonstrated that J2H enriched at least four gut bacterial species with fucoidan-degrading potential, including Bacteroides sartorii and Bacteroides acidifaciens. Our findings suggest that the low molecular weight S. japonica fucan, J2H, is a promising potential agent for obesity prevention and its enrichment of gut bacteria with fucoidan-degrading potential may play a vital role in the anti-obesity effects.

Structural diversity of fucoidans and their radioprotective effect

Fucoidans are biologically active sulfated polysaccharides of brown algae. They have a great structural diversity and a wide spectrum of biological activity. This review is intended to outline what is currently known about the structures of fucoidans and their radioprotective effect. We classified fucoidans according to their composition and structure, examined the structure of fucoidans of individual representatives of algae, summarized the available data on changes in the yields and compositions of fucoidans during algae development, and focused on information about underexplored radioprotective effect of these polysaccharides. Based on the presented in the review data, it is possible to select algae, which are the sources of fucoidans of desired structures and to determine the best time to harvest them. The use of high purified polysaccharides with established structures increase the value of studies of their biological effects and the determination of the dependence "structure - biological effect".

Sargassum fusiforme Polysaccharides Prevent High-Fat Diet-Induced Early Fasting Hypoglycemia and Regulate the Gut Microbiota Composition

A low fasting blood glucose level is a common symptom in diabetes patients and can be induced by high-fat diet (HFD) feeding at an early stage, which may play important roles in the development of diabetes, but has received little attention. In this study, five polysaccharides were prepared from Sargassumfusiforme and their effects on HFD-induced fasting hypoglycemia and gut microbiota dysbiosis were investigated. The results indicated that C57BL/6J male mice fed an HFD for 4 weeks developed severe hypoglycemia and four Sargassumfusiforme polysaccharides (SFPs), consisting of Sf-2, Sf-3, Sf-3-1, and Sf-A, significantly prevented early fasting hypoglycemia without inducing hyperglycemia. Sf-1 and Sf-A could also significantly prevent HFD-induced weight gain. Sf-2, Sf-3, Sf-3-1, and Sf-A mainly attenuated the HFD-induced decrease in Bacteroidetes, and all five SFPs had a considerable influence on the relative abundance of Oscillospira, Mucispirillum, and Clostridiales. Correlation analysis revealed that the fasting blood glucose level was associated with the relative abundance of Mucispinllum and Oscillospira. Receiver operating characteristic analysis indicated that Mucispinllum and Oscillospira exhibited good discriminatory power (AUC = 0.745-0.833) in the prediction of fasting hypoglycemia. Our findings highlight the novel application of SFPs (especially Sf-A) in glucose homeostasis and the potential roles of Mucispinllum and Oscillospira in the biological activity of SFPs.