Effects of a β-type glycosidic polysaccharide from Flammulina velutipes on anti-inflammation and gut microbiota modulation in colitis mice

Using the Flammulina velutipes polysaccharide (FVP) extracted from our previous study, herein, we investigated the improvement of this β-type glycosidic polysaccharide in alleviating dextran sodium sulfate-induced ulcerative colitis (UC) in mice.

Digestive Property and Bioactivity of Blackberry Polysaccharides with Different Molecular Weights

In the present study, the digestion and fermentation of blackberry polysaccharides (BBPs) with different molecular weights (M_w) were investigated. The results showed that the M_w decrease rates of BBP, BBP-8, BBP-16, and BBP-24 were 77.48, 69.61, 56.87, and 52.89%, respectively. The antioxidant and α-glucosidase inhibitory activities of BBPs were decreased under gastrointestinal condition, which might be due to the variation of M_w during digestion. The bile acid-binding ability of BBPs showed an M_w-dependent manner for higher M_w polysaccharides with higher viscosity. Through fermentation, the BBPs affected the ecosystem of the intestinal tract by promoting the production of short-chain fatty acids, lowering the pH of colon, and decreasing the ratio of Firmicutes to Bacteroidetes. All BBPs showed almost a similar modulation effect on the gut bacteria, but the lower M_w polysaccharide was more easily utilized by bacteria.

Purification, Characterization, Prebiotic Preparations and Antioxidant Activity of Oligosaccharides from Mulberries

A water-soluble oligosaccharide termed EMOS-1a was prepared by enzymatic hydrolysis of polysaccharides purified from mulberries by column chromatography. The chemical structure of the purified fraction was investigated by ultraviolet spectroscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectrometry, which indicated that galactose was the main constituent of EMOS-1a. Chemical analyses showed that the uronic acid and sulfate content of EMOS-1a were 5.6% and 8.35%, respectively, while gel permeation chromatography showed that EMOS-1a had an average molecular weight of 987 Da. The antioxidant activities of EMOS-1a were next investigated, and EMOS-1a exhibited concentration-dependent 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, Trolox equivalent antioxidant capacity, and ferric reducing antioxidant power. The level of proliferation of Lactobacillus rhamnosus reached 1420 ± 16% when 4% (w/v) EMOS-1a was added, where the number of colonies in MRS (de Man, Rogosa, and Sharpe) medium with no added oligosaccharide was defined as 100% proliferation. These results indicate that the oligosaccharide EMOS-1a could be used as a natural antioxidant in prebiotic preparations.

Evaluation of Prebiotic Potential of Three Marine Algae Oligosaccharides from Enzymatic Hydrolysis

Alginate oligosaccharides (AlgO), agarose oligosaccharides (AO), and κ-carrageenan oligosaccharides (KCO) were obtained by specific enzymatic hydrolysis method. The molecular weight distributions of the three oligosaccharides were 1.0⁻5.0 kDa, 0.4⁻1.4 kDa, and 1.0⁻7.0 kDa, respectively. The culture medium was supplemented with the three oligosaccharides and fermented by pig fecal microbiota in vitro, for 24 h. Each oligosaccharide was capable of increasing the concentration of short-chain fatty acids (SCFAs), especially butyric acid, and altering the microbiota composition. Linear discriminant analysis effect size (LEfSe) analysis results showed that the opportunistic pathogenic bacteria Escherichia, Shigella, and Peptoniphilus, were significantly decreased in AlgO supplemented medium. AO could improve the gut microbiota composition by enriching the abundance of Ruminococcaceae, Coprococcus, Roseburia, and Faecalibacterium. Besides, KCO could increase the abundance of SCFA microbial producers and opportunistic pathogenic flora. Therefore, these results indicate that AlgO and AO can be used as gut microbial regulators and can potentially improve animal/human gastrointestinal health and prevent gut disease, whereas the physiological function of KCO needs further evaluation.

Protective effect of mulberry (Morus atropurpurea) fruit against diphenoxylate-induced constipation in mice through the modulation of gut microbiota

The protective effect of mulberry (Morus atropurpurea) fruit against diphenoxylate-induced constipation in mice through the modulation of gut microbiota.

Bioaccessibility, antioxidant activity and modulation effect on gut microbiota of bioactive compounds from Moringa oleifera Lam. leaves during digestion and fermentation in vitro

This study aims to investigate the bioaccessibility, bioactivity and gut microbiota modulation effect of Moringa oleifera Lam. leaves after in vitro gastrointestinal digestion and colonic fermentation.

The impacts of natural polysaccharides on intestinal microbiota and immune responses – a review

This paper presents a comprehensive review of the impacts of natural polysaccharides on gut microbiota and immune responses as well as their interactions.

Modulation of gut microbiota by mulberry fruit polysaccharide treatment of obese diabetic db/db mice

Increasing evidence indicates that gut microbiota is an important factor in mediating the development of metabolic disorders, especially type 2 diabetes. Herein, we investigated the protective effects of polysaccharides from mulberry fruit on diabetic db/db mice. We observed an inhibition in the body weight increase, a decrease in the blood glucose levels, and an improvement in glucose tolerance. Furthermore, our data showed increased enzymatic activities as evidenced by parameters such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT). In addition, high density lipoprotein cholesterol (HDL-C) increased, while total cholesterol (TC), triacylglycerol (TG), low density lipoprotein cholesterol (LDL-C), lipid peroxide content malonaldehyde (MDA), and free fatty acid (FFA) levels decreased, accompanied by the recovery from damage to the liver, kidneys and pancreas. Meanwhile, metformin and polysaccharide similarly shifted the abundance of the main gut microbiota, Bacteroidetes and Firmicutes, in diabetic mice toward levels observed in healthy mice. Especially at the genus level, the enrichment of some key bacteria like Bacteroidales, Lactobacillus, Allobaculum, Bacteroides, and Akkermansia was observed. Taken together, our findings suggest that polysaccharides from the mulberry fruit modulate gut microbiota, including enriching functional bacteria and reducing microbial diversity, which may contribute to their antidiabetic effects.

Structural characterization and in vitro fermentation of a novel polysaccharide from Sargassum thunbergii and its impact on gut microbiota

The aim of the present study was to investigate structural characteristic and in vitro fermentation of a novel polysaccharide named ST-P2 from Sargassum thunbergii by human fecal inoculums, and its impact on human colonic microbiota. The results showed that ST-P2 was homogeneous with molecular weight of 48,788 Da, and consisted of arabinose, galactose, glucose, xylose, and mannose. The main linkage types were identified as (1 → 5)-α-L-Araf, (1 → 3)-α-L-Manp, (1 → 3,6)-β-D-Galp, (1 → 6)-α-D-Glcp, and (1 → 3)-β-D-Xylp, respectively. After 48 h fermentation, 67.83 ± 1.15% of total carbohydrate was utilized by colonic microbiota. The pH value in the fecal culture significantly decreased from 6.09 ± 0.11 to 4.70 ± 0.04. The concentrations of total short chain fatty acids, acetic, propionic, n-butyric and n-valeric acids significantly increased compared to the blank. ST-P2 could remarkably modulate the composition and abundance of beneficial microbiota. These results suggest that ST-P2 could potentially be a functional food aimed at promoting the gut health.

Simulated Digestion and Fermentation in Vitro by Human Gut Microbiota of Polysaccharides from Bee Collected Pollen of Chinese Wolfberry

Digestion and fermentation in vitro of polysaccharides from bee collected pollen of Chinese wolfberry (WBPPS) were investigated in the present study. It was found that WBPPS mainly consisted of mannose, ribose, rhamnose, galacturonic acid, glucose, galactose, xylose, and arabinose in a molar ratio of 0.38:0.09:0.17:0.64:0.22:0.67:0.08:1.03, respectively. WBPPS was not affected by human saliva. The fraction A (molecular weight 1340 kDa) of WBPPS was not broken down in simulated gastric and small intestinal juices, while the small fraction B (molecular weight 523 kDa) of WBPPS was degraded. Moreover, fermentation in vitro revealed that WBPPS could significantly enhance the production of short-chain fatty acids and modulate gut microbiota composition via increasing the relative abundances of genera Prevotella, Dialister, Megamonas, Faecalibacterium, and Alloprevotella and decreasing the numbers of genera Bacteroides, Clostridium XlVa, Parabacteroides, Escherichia/Shigella, Phascolarctobacterium, Parasutterella, Clostridium sensu stricto, and Fusobacterium.

Gut Fermentation of Dietary Fibres: Physico-Chemistry of Plant Cell Walls and Implications for Health

The majority of dietary fibre (DF) originates from plant cell walls. Chemically, DF mostly comprise carbohydrate polymers, which resist hydrolysis by digestive enzymes in the mammalian small intestine, but can be fermented by large intestinal bacteria. One of the main benefits of DF relate to its fermentability, which affects microbial diversity and function within the gastro-intestinal tract (GIT), as well as the by-products of the fermentation process. Much work examining DF tends to focus on various purified ingredients, which have been extracted from plants. Increasingly, the validity of this is being questioned in terms of human nutrition, as there is evidence to suggest that it is the actual complexity of DF which affects the complexity of the GIT microbiota. Here, we review the literature comparing results of fermentation of purified DF substrates, with whole plant foods. There are strong indications that the more complex and varied the diet (and its ingredients), the more complex and varied the GIT microbiota is likely to be. Therefore, it is proposed that as the DF fermentability resulting from this complex microbial population has such profound effects on human health in relation to diet, it would be appropriate to include DF fermentability in its characterization-a functional approach of immediate relevance to nutrition.