Correction: Zhang et al. Fucoidan from Laminaria japonica Ameliorates Type 2 Diabetes Mellitus in Association with Modulation of Gut Microbiota and Metabolites in Streptozocin-Treated Mice. Foods 2023, 12, 33.

In the original publication, there was a mistake in Figure 3 as published [...].

Scytosiphon lomentaria fucoidan ameliorates DSS-induced colitis in dietary fiber-deficient mice via modulating the gut microbiota and inhibiting the TLR4/NF-κB/MLCK pathway.

The prevalence of ulcerative colitis (UC) poses a serious threat to human health. This study showed that fiber-deficient diet (FD) increased the susceptibility of mice to low dosage of DSS-induced UC, and a UC model was established by feeding mice with DSS and FD to evaluate the effect of Scytosiphon lomentaria fucoidan (SLF) on UC. SLF ameliorated the symptoms of UC, as evidenced by increases in colon length, goblet cells and glycoprotein and reduction in inflammatory cell infiltration and intestinal epithelial injury. SLF alleviated oxidative stress and inhibited colonic inflammation by reducing the levels of lipopolysaccharides and pro-inflammatory cytokines and suppressing the activation of nuclear factor kappa B pathway. SLF protected tight junction integrity by reducing the level of myosin light chain kinase and increasing the levels of claudin, zonula occludens-1 and occludin. SLF improved serum metabolites profile and affected multiple metabolic pathways that are crucial to human health, e.g. butanoate metabolism. The underlying mechanism can be associated with modulation of the gut microbiota and metabolites, including increases in short chain fatty acids and reduction in Proteobacteria, Bacteroides and Romboutsia. It suggests that SLF could be developed as a prebiotic polysaccharide to benefit human health by improving intestinal microecology.

Undaria pinnatifida fucoidan contributes to anti-inflammation activity of Bacteroides in fiber-deficient mice via modulation of gut microbiota and protection of intestinal barrier integrity.

Bacteroides as potential probiotics has several health benefits to the host, but its practical application faces many challenges due to its inherent properties. In this study, Bacteroides strains isolated from human feces alleviated colonic inflammation in mice, as evidenced by increased colon length and reduced tissue damage. Further study showed that anti-inflammation activity of Bacteroides strains was disturbed by dietary fiber deficiency (FD), which disrupted the balance between gut microbiota and colonic mucus layer, leading to a thinning of colonic mucus layer. A combination of Bacteroides strains and Undaria pinnatifida fucoidan (UPF) better alleviated colonic inflammation than either of them, including increases in the densities of goblet cells and glycoproteins and reduction in intestinal epithelial damage, pro-inflammatory cytokines and oxidative stress. The underlying mechanisms can be attributed to that UPF-induced alterations of mucosal microbiota cannot only directly benefit host health but also create an ecological condition that facilitates Bacteroides strains exert their healthy properties. In addition, both Bacteroides strains and UPF improved FD-induced lipid metabolism abnormality, mainly involving glycerophospholipid metabolism pathway. This study suggests that the application of Bacteroides has certain limitations, and UPF can be developed as a probiotic adjuvant for Bacteroides to enhance human health.

Undaria pinnatifida fucoidan ameliorates dietary fiber deficiency-induced inflammation and lipid abnormality by modulating mucosal microbiota and protecting intestinal barrier integrity.

Dietary fiber deficiency (FD) is a new public health concern, with limited understanding of its impact on host energy requirements and health. In this study, the effect of fucoidan from Undaria pinnatifida (UPF) on FD-induced alterations of host physiological status was analyzed in mice. UPF increased colon length and cecum weight, reduced liver index, and modulated serum lipid metabolism primarily involving glycerophospholipid and linoleic acid metabolism in FD-treated mice. UPF protected against FD-induced destruction of intestinal barrier integrity by upregulating the expression levels of tight junction proteins and mucin-related genes. UPF alleviated FD-induced intestinal inflammation by reducing the levels of inflammation-related factors, such as interleukin-1ß, tumor necrosis factor-α, and lipopolysaccharides, and relieving oxidative stress. The underlying mechanism can be closely associated with modulation of gut microbiota and metabolites, such as a reduction of Proteobacteria and an increase in short chain fatty acids. The in vitro model showed that UPF mitigated H2O2-induced oxidative stress and apoptosis in IEC-6 cells, indicating its potential as a therapeutic agent for inflammatory bowel disorders. This study suggests that UPF can be developed as a fiber supplement to benefit host health by modulating gut microbiota and metabolites and protecting intestinal barrier functions.

Fucoidan from Scytosiphon lomentaria protects against destruction of intestinal barrier, inflammation and lipid abnormality by modulating the gut microbiota in dietary fibers-deficient mice.

Inadequate dietary fibers intake has been a threat for public health, and its adverse effect and regulatory mechanisms remain unclear. In this study, the protective effect of fucoidan from Scytosiphon lomentaria (SLF) on dietary fibers deficiency (FF)-induced change of physiological functions was analyzed in mice. SLF reduced weight gain and low-density lipoprotein cholesterol, increased high-density lipoprotein cholesterol, but had no effect on food intake and body fat mass in FF-treated mice. Lipidomics analysis showed that SLF modulated lipid metabolism, mainly involving glycerophospholipid and linolenic acid metabolism pathways. In addition, SLF protected against FF-induced colon damages, including the integrity of epithelial cell layer, loss of goblet cells, crypts and glycoproteins, and inflammatory cells infiltration. The underlying mechanisms can be associated with inhibition of oxidative stress, increase of tight junction proteins, and regulation of cytokines profile via nuclear factor kappa B pathway. On the other hand, SLF modulated FF-induced gut microbiota dysbiosis that had close relation with host physiological functions, e.g. increases in Akkermansia, Parabacteroides, Bacteroides and Alistipes. It indicates that SLF can be developed as a prebiotic agent to benefit host health through protecting intestinal barrier and regulating the gut microbiota.

Fabrication of astaxanthin-enriched colon-targeted alginate microspheres and its beneficial effect on dextran sulfate sodium-induced ulcerative colitis in mice.

Astaxanthin (Ax) with a strong antioxidant activity is beneficial to human health, but its application is limited by its highly unsaturated structure and poor water-solubility. Ax-enriched colon targeted alginate particles (Ax-Alg) was prepared by high-pressure spraying and ionic gelation, and most of particles was in the range of 0.5-3.2 µm in a diameter. The in vitro models showed that Ax-Alg can maintain the structural integrity in the different conditions (pH, heat and ion). In addition, Ax-Alg can well tolerate the conditions in the mouth, stomach and small intestine and reach the colon where Ax was released due to fermentation of gut microbiota. Mice experiment showed that Ax-Alg reduced dextran sulfate sodium-induced colitis, involving weight loss, disease activity index, colonic mucosal integrity and inflammation, and oxidative damage. On the other hand, Ax-Alg regulated the gut microbiota composition and reduced the abundances of Bacteroidetes members that had positive correlation with ulcerative colitis. Ax-Alg had better effect on the treatment of ulcerative colitis than oil-in-water emulsion, which can be attributed to the synergistic effect of Ax and alginate. This study can be helpful for the application of colon-targeted delivery system in the foods and treatment of colon diseases.

Polysaccharides from edible brown seaweed Undaria pinnatifida are effective against high-fat diet-induced obesity in mice through the modulation of intestinal microecology.

Brown seaweed is rich in polysaccharides including sulfated polysaccharides and alginate, both of which provide health benefits to the host but whose differences have not received sufficient attention. In this study, alginate from Undaria pinnatifida (UPA) and sulfated polysaccharides from U. pinnatifida (UPSP) were isolated, and their action was analyzed in high fat diet-fed mice. UPA and UPSP improved body composition, fat deposition in body tissues and organs, lipid abnormality and inflammatory response in mice, and compound polysaccharides from U. pinnatifida (UPP: UPA + UPSP) had a better effect on some physiological indexes, which could be attributed to the differences in the gut microbiota. Both UPSP and UPA modulated diet-induced microbiota dysbiosis, and UPP had better effect on changes in the gut microbiota, including an increase in Bacteroidales and reduction in both Clostridiales and Lactobacillales that had positive correlations with the improvement of the physiological status. The in vitro model of bacterial culture revealed that the use of Bacteroides on UPA and UPSP was species dependent, and UPP can better maintain the diversity and stability of the Bacteroidales community. This study indicated that polysaccharides from edible brown seaweed can benefit host health by improving the intestinal microecology, which can be helpful for the application of edible brown seaweed in health foods.

Fucoidan from Laminaria japonica Ameliorates Type 2 Diabetes Mellitus in Association with Modulation of Gut Microbiota and Metabolites in Streptozocin-Treated Mice.

Chronic diseases have been a leading cause of death worldwide, and polysaccharide supplementation is an effective therapeutic strategy for chronic diseases without adverse effects. In this study, the beneficial effect of Laminaria japonica fucoidan (LJF) on type 2 diabetes mellitus (T2DM) was evaluated in streptozocin-treated mice. LJF ameliorated the symptoms of T2DM in a dose-dependent manner, involving reduction in weight loss, water intake, triglyceride, blood glucose, cholesterol and free fatty acids, and increases in high-density lipoprotein cholesterol, catalase, glucagon-like peptide-1, and superoxide dismutase. In addition, LJF regulated the balance between insulin resistance and insulin sensitivity, reduced islet necrosis and ß-cell damage, and inhibited fat accumulation in T2DM mice. The protective effect of LJF on T2DM can be associated with modulation of the gut microbiota and metabolites, e.g., increases in Lactobacillus and Allobaculum. Untargeted and targeted metabolomics analysis showed that the microbiota metabolite profile was changed with LJF-induced microbiota alterations, mainly involving amino acids, glutathione, and glyoxylate and dicarboxylate metabolism pathways. This study indicates that LJF can be used as a prebiotic agent for the prevention and treatment of diabetes and microbiota-related diseases.

Sulfated polysaccharides from pacific abalone attenuated DSS-induced acute and chronic ulcerative colitis in mice via regulating intestinal micro-ecology and the NF-κB pathway.

Due to potential side effects of current drugs in colitis treatment, polysaccharides with anti-inflammatory activities can be considered as alternative molecules for colitis treatment. Sulfated polysaccharide from pacific abalone (AGSP) reduced the level of lipopolysaccharides (LPS) and increased the production of short chain fatty acids in the colon of mice, and it reduced the levels of interleukin (IL)-6, IL-1ß and tumor necrosis factor (TNF)-α and increased the IL-10 level in in vitro cell models, suggesting that it can be used as a probiotic agent to inhibit intestinal inflammation. Furthermore, AGSP reduced the disease activity index and intestinal damage, improved the mucosal immune response, and inhibited oxidative damage in mice with DSS-induced acute and chronic colitis, which can be associated with modulation of the NF-κB signaling pathway and gut microbiota. AGSP regulated the structure of the gut microbiota and reduced the level of Bacteroides that had positive correlation with the colitis symptoms. The in vitro result showed that AGSP may inhibit mucin degradation by Bacteroides via the change of the polysaccharide utilization strategy, which can protect intestinal barrier integrity. This study is useful to understand the mechanism by which AGSP ameliorates colitis and related diseases and promotes further development of AGSP.

Low-molecular alginate improved diet-induced obesity and metabolic syndrome through modulating the gut microbiota in BALB/c mice.

Alginate is the most abundant polysaccharide in brown seaweed, which is widely used as a food additive, but its high viscosity and gel property limit its applications in foods as a functional ingredient. In this study, low-molecular alginate from Laminaria japonica (L-LJA) was prepared, and its effect on obesity and metabolic syndrome was analyzed in high-fat diet (HFD)-fed mice. L-LJA reduced weight gain, fat accumulation in the liver and epididymal adipose tissue, lipid abnormality and inflammation in HFD-fed mice accompanied with the improvement of gut microbiota. L-LJA modulated the structure of gut microbiota, increased some Bacteroidales members, and reduced some Clostridiales members in mice, which were positively correlated with the improvement of physiological status. Fecal transplant from L-LJA-fed mice reduced fat accumulation in body tissues and lipid abnormality in the serum and liver and increased short chain fatty acids production in HFD-fed mice, confirming that L-LJA-induced gut microbiota alteration played an important role in its bioactivity. L-LJA has better solubility and can be utilized in food systems in high dose, implying that it can be developed as a prebiotic agent to increase both economic value and nutritive value of alginate.

Sulfated polysaccharides from Undaria pinnatifida improved high fat diet-induced metabolic syndrome, gut microbiota dysbiosis and inflammation in BALB/c mice.

Undaria pinnatifida was shown to reduce serum lipids and fat accumulation and produce beneficial effect on type 2 diabetes, but its effect on intestinal micro-ecology remains unclear. This study showed that sulfated polysaccharides from U. pinnatifida (UPSP) reduced weight gain, fat accumulation and metabolic disorders in mice fed with high fat diet (HFD). UPSP not only alleviated HFD-induced microbiota dysbiosis indicated as increased abundances of some Bacteroidales members that had positive correlations with the improvement of physiological indexes, but also maintained gut barrier integrity and reduced metabolic endotoxemia. A dose-effect relationship was observed between the dose of UPSP and its effect on some physiological indexes, gut microbiota community and nutrient utilization. The in vitro result showed that the use of Bacteroides species within Bacteroidales on UPSP was species-dependent, and the dose of UPSP affected the growth properties of some Bacteroides species. It implied that UPSP can be considered as prebiotic agent to prevent gut dysbiosis and obesity-related diseases in obese individuals.

Effect of sulfate group on sulfated polysaccharides-induced improvement of metabolic syndrome and gut microbiota dysbiosis in high fat diet-fed mice.

Sulfated polysaccharides were shown to benefit metabolic syndrome (MS) and gut microbiota, but the contribution of sulfate group remains unclear. In this study, sulfated polysaccharides from pacific abalone (AGSP) and its desulfated product (D-AGSP) were prepared, and the contribution of sulfate group was analyzed via in vitro and in vivo models. The result showed that sulfate group had no obvious effect on the reaction of AGSP with RAW 264.7 cells, but it affected the growth properties of gut microbes that able to utilize AGSP. The mice experiment showed that D-AGSP reduced weight gain, fat accumulation and lipid metabolism disorder in HFD-fed mice as well as AGSP, and no differences between them were found. Sequencing analysis showed that sulfate group influenced AGSP-induced alterations of the gut microbiota at higher taxonomic levels, some of which had close correlation with the improvement of physiological index. These results implied that sulfate group may partially determine the activities of polysaccharides via gut microbiota-mediated pathway, but the exact mechanisms need further research.

Analysis of amantadine in Laminaria Japonica and seawater of Daqin Island by ultra high performance liquid chromatography with positive electrospray ionization tandem mass spectrometry.

A sensitive and validated method for determination of amantadine in Laminaria Japonica and seawater was established using ultra high performance liquid chromatography with positive electrospray ionization tandem spectrometry (UHPLC-ESI-MS/MS). Laminaria Japonica was extracted with acetonitrile containing formic acid (1%), then purified with 10.0 g anhydrous sodium sulfate, 0.50 g C18 and 0.50 g PSA powder. Seawater added 10.0 mL 0.20 mol/L hydrochloric acid was purified with MCX solid phase extraction (SPE) cartridge. After extraction and purification, the supernatant of Laminaria Japonica and eluate of seawater were evaporated to nearly dry under a gentle stream of nitrogen at 40 °C. Acetonitrile-0.1% formic acid in water (3/7, v/v) was adjusted to 1.00 mL final volume. An aliquot (10 µL) was injected into the C18 column for separation with the mobile phase of acetonitrile and 0.1% formic acid in water at 0.25 mL·min-1. Calibration curves were linear ranged from 1.00 ng/mL to 20.0 ng/mL. Mean recoveries were 73.5% to 95.8%, and limit of detection (LOD) and quantification (LOQ) were 0.50 µg/kg and 1.00 µg/kg for Laminaria Japonica. Mean recoveries were 75.8% to 93.4%, and LOD and LOQ were 0.50 ng/L and 1.00 ng/L for seawater. Based on the method above, Laminaria Japonica and seawater in Daqin Island were analyzed in February to June continuously, lgBAF3.71 (bioaccumulation factor), indicating a bioenrichment effect.

Response of antioxidase in viscera of Pagrosuma major larvae to water soluble fraction of hydrocarbons in No.0 diesel oil.

Pagrosomus major larvae were exposed to the water-soluble fraction of hydrocarbon in No.0 diesel oil (corresponding to No.2 fuel oil) at concentrations of 0, 0.17, 1.22 and 8.82 mg/L for up to 15 days. Larvae were sampled on days 9 and 15 of the experiment. Supernatants of viscera tissue extractions were assayed for biochemical response in terms of oxidative stress-superoxide dismutase(SOD), activity of selenium-dependant glutathione peroxidase(Se-GPx) and catalase (Ca), and the concentration of reduced glutathione (GSH). On day 9 of exposure, statistically significant dose-related increases in Se-GPx and SOD activity, and GSH concentration were ohserved in all cases except for Se-GPx activity under the highest dosage of hydrocarbon. However, on day 15 of exposure, a similar dose-related response was only observed for Se-GPx activity. GSH concentration decreased and SOD activity showed no statistical difference as compared to controls. However, a significant decrease in compared to day 9 Se-GPx activity and GSH concentration, in contrast to increase SOD activity at day 15 as indicates an accelerated accumulation of H2O2 and potential oxidative damage under long-term exposure of larvae to hydrocarbons. No statistical changes were observed in Ca activity throughout the experiment, possibly owing to the high efficiency of Se-GPx. A recovery experiment was performed on indicating that the response of antioxidants measured tending to return to their control levels. These results prove the function of the antioxidant defense system of the larvae to the water-soluble fraction of hydrocarbons in No.0 diesel oil.

[Effects of BaP exposure on ultrastructures of hepatic cells of Boleophthalmus pectinirostris].

The changes of ultrastructures of hepatic cells of Boleophthalmus pectinirostris were investigated after the fish were exposed under benzo(a) pyrene in different concentrations under experimental condition. The results showed that the organelles in hepatic cells of B. pectinirostris were damaged to different extents after the fish was exposed under lower concentration of BaP (0.5 mg.L-1) for up to 7 d, in which, mitochondria and endoplasmic reticulum were the chief organelles affected by BaP exposure. While the fish was exposed under higher concentration of BaP (5 mg.L-1) for 2 h, almost all of the organelles including mitochondria and endoplasmic reticulum in hepatic cells of B. pectinirostr were affected by BaP exposure. The structures of liver cells were seriously damaged. It was demonstrated that BaP could produce multiorganalle lesions in hepatic cells of B. pectinirostris, and the severity extent of such lesions was dependent on the concentration level of BaP.