Plant-derived Polysaccharides Research Articles

Biochemical characterization of a SusD-like protein involved in β-1,3-glucan utilization by an uncultured cow rumen Bacteroides.

In ruminants, the rumen is a specialized stomach that is adapted to the breakdown of plant-derived complex polysaccharides through the coordinated activities of a diverse microbial community. Bacteroidota is a major phylum in this bovine rumen microbiota. They contain several clusters of genes called polysaccharide utilization loci (PULs) that encode proteins working in concert to capture, degrade, and transport polysaccharides. Despite the critical role of SusD-like proteins for efficient substrate transport, they remain largely unexplored. Here, we present the biochemical characterization of a SusD-like protein encoded by a β-glucan utilization locus from an Escherichia coli metagenomic clone previously isolated by functional screening of the bovine rumen microbiome. In this study, we show that clone 41O1 can grow on laminaritriose, cellotriose, and a mixture of cellobiosyl-cellobiose and glucosyl-cellotriose as sole carbon sources. Based on this, we used various in vitro analyses to investigate the binding ability of 41O1_SusD-like towards these oligosaccharides and the corresponding polysaccharides. We observed a clear binding affinity for β-1,6 branched β-1,3-glucans (laminarins, yeast β-glucan) and laminaritriose. Comparison of the AlphaFold2 model of 41O1_SusD-like with its closest structural homologs highlights a similar pattern of substrate recognition. In particular, three tryptophan residues are shown to be crucial for laminarin recognition. In the context of the cow rumen, we discuss the possible substrates targeted by the 41O1_PUL, such as the (1,3;1,4)-β-d-glucans present in cereal grains or the β-1,3- and (1,3;1,6)-β-d-glucans that are components of the cell wall of ruminal yeasts.IMPORTANCEThe rumen microbiota can majorly impact overall animal health, feed efficiency, and release of harmful substances into the environment. This microbiota is involved in the fermentation of organic matter to provide the host with valuable and assimilable nutrients. Bacteroidota efficiently captures, breaks down, and imports complex polysaccharides through the concerted action of proteins encoded by polysaccharide utilization loci (PULs). Within this system, SusD-like protein has proven necessary for the active internalization of the substrate. Nevertheless, the vast majority of SusD-like proteins characterized to date originate from cultured bacteria. With regard to the diversity and importance of uncultured bacteria in the rumen, further studies are required to better understand the role of polysaccharide utilization loci in ruminal polysaccharide degradation. Our detailed characterization of the 41O1_SusD-like therefore contributes to a better understanding of the carbohydrate metabolism of an uncultured Bacteroides from the cow rumen.

Effects of different chemical modifications on physicochemical and antioxidation properties of Lycium barbarum seed dreg polysaccharides

Recent studies have witnessed that chemical modification can improve the physicochemical and functional properties of plants' polysaccharides. Herein, we modified the natural Lycium barbarum seed dreg polysaccharides (LBSDPs) by sulfation (S-LBSDPs), phosphorylation (P-LBSDPs), and carboxymethylation (C-LBSDPs), and evaluated the chemical composition and antioxidant activity of their derivatives. Natural polysaccharides and their derivatives exhibited typical polysaccharide absorption peaks and characteristic group absorption peaks in FT-IR spectra along with maximum UV absorption. After modification, the total sugar and protein contents of the derivatives were decreased, whereas the uronic acid content was increased. Among the three derivatives, sulfated polysaccharides displayed excellent thermal stability. S-LBSDP and P-LBSDP showed the highest ABTS radical scavenging and reducing power while S-LBSDPs and C-LBSDPs showed better DPPH radical scavenging effect, and P-LBSDPs showed considerable Fe2+ chelating ability. Our data indicate that chemical modifications can impart a positive effect on the antioxidant potential of plant-derived polysaccharides.

Atractylodes lancea Rhizome Polysaccharide Alleviates Immunosuppression and Intestinal Mucosal Injury in Mice Treated with Cyclophosphamide.

Plant-derived polysaccharides, such as Atractylodes lancea rhizome polysaccharide (ALP), are good immune regulators. However, the immune regulatory mechanism of the ALP is unknown. This study aimed to evaluate the effects of ALP on the intestinal mucosal barrier and intestinal mucosal immunity of immunosuppressed mice. We also compared the activity of raw Atractylodes lancea rhizome polysaccharide (SALP) with wheat bran processed bran-fried Atractylodes lancea rhizome polysaccharide (FALP; both at 1.2 g/kg/d for mice). Our results showed that ALP effectively increased the immune organ index and blood cell count, stimulated the secretion of cytokines, and promoted the expression of occludin and zonula occludens-1 (ZO-1). ALP also promoted the expression of T cells and the secretion of sIgA. Furthermore, ALP alleviated the gut microbiota disorder in Cy-treated mice and increased the relative abundances of Lactobacillus and Faecalibaculum. ALP reversed the decrease in the level of SCFAs and promoted the expression of G protein-coupled receptor 43 (GPR43). To our knowledge, this study was the first to explore how the ALP protects the intestinal mucosal barrier and enhances intestinal mucosal immunity by alleviating the gut microbiota imbalance and metabolic disorders of SCFAs. FALP was more therapeutic than SALP, suggesting that FALP could be developed as a promising functional food component.

Preparation of carbon-rich material from Dendrobium officinale polysaccharide in deep eutectic system

A carbon-rich material (DESysChar) was prepared from polysaccharide within a deep eutectic system (DESys) containing oxalic acid, and systematically characterized using various analytical techniques. The investigation of reaction mechanism revealed concurrent dehydration and etherification processes. This study commenced with the extraction of plant polysaccharide using the DESys-based mechanochemical extraction method from Dendrobium officinale. Subsequently, the DESys method was used to carbonize the extracted Dendrobium officinale polysaccharide and produce DESysChar. DESysChar was then used for the adsorption and determination of pollutants in water. This study represents a significant advancement in eco-friendly material synthesis, enabling the low-temperature (120 °C) carbonization of plant-derived polysaccharides, thereby reducing energy consumption and environmental impact. The effective adsorption of methylene blue by DESysChar underscores its potential in environmental remediation. This study presents a more responsible and efficient approach to polysaccharide extraction and carbonization, addressing environmental concerns. Embracing the 4S workflow (involving Sustainable raw materials converted into Sustainable degradable products, by using Sustainable technology throughout the process to create a Sustainable environment) promotes sustainability in material development, laying the foundation for future eco-friendly practices in various industries. In summary, this study propels sustainable polysaccharide development for widespread use.

Effects of three different plant-derived polysaccharides on growth performance, immunity, antioxidant function, and cecal microbiota of broilers.

This study investigated the effects of dietary plant polysaccharides on growth performance, immune status and intestinal health in broilers. We randomly divided 960 one-day-old Arbor Acres broiler chicks into 4 groups. The control (CON) group was fed a basal diet, and the remaining groups were fed a basal diet supplemented with 1,000 mg/kg ginseng polysaccharide (GPS), astragalus polysaccharides (APS), or Salvia miltiorrhiza polysaccharide (SMP) for 42 d. Dietary supplementation with SMP significantly increased BW at 21 and 42 days of age, ADG and ADFI during the starter and whole experimental period, decreased the concentrations of IL-1β, TNF-α and MDA, increased the levels of IL-4 and IL-10 and CAT activity in the serum (P < 0.05). GPS, APS, and SMP supplementation increased serum levels of immunoglobulins, activities of GSH-Px, T-SOD and T-AOC, and cecal concentrations of acetic acid and propionic acid of broilers (P < 0.05). Furthermore, high-throughput sequencing results showed that the relative abundance of Firmicutes was decreased while the relative abundance of Bacteroidota, Alistipes, and Prevotellaceae_NK3B31_group were increased (P < 0.05) in the GPS, APS, and GMP groups compared with the CON group. Dietary GPS, APS, and SMP supplementation could improve growth performance, enhance immune function by increasing serum immunoglobulin and regulating cytokines, improve antioxidant function by increasing serum antioxidant enzyme activity, increase volatile fatty acid levels and improve the microbial composition in the cecum of broilers. Dietary SMP supplementation had the optimal effect in this study. This article is protected by copyright. All rights reserved.

Glycan-related genes in human gut microbiota exhibit differential distribution and diversity in carbohydrate degradation and glycan synthesis.

Interactions between humans and the gut microbiome occur by supplying nutrients to gut epithelial cells via short-chain fatty acids obtained from dietary carbohydrates or mucins and activating immunity via mucins' degradation. The degradation of carbohydrates derived from food is an important function for organisms to obtain energy. However, since humans possess only 17 genes encoding carbohydrate-degrading enzymes, the gut microbiome is responsible for degrading plant-derived polysaccharides. Using the method for extracting glycan-related genes from the metagenomes constructed thus far, we calculated the distribution and abundance of different glycan-related genes in the healthy human gut metagenome. Glycan-related genes showed an abundance of 0.64-11.00, indicating large individual differences. However, the distribution of the classes of glycan-related genes was similar between the samples. In addition, the function of carbohydrate degradation was divided into three clusters, showing high diversity; however, the synthesis function was not divided, indicating low diversity. The substrates of enzymes for carbohydrate degradation between clusters were either plant-derived polysaccharides or biased toward degrading polysaccharides derived from other sources. These functional biases differ depending on the type of microorganism used. Based on these findings, we predicted that 1) diversity will be constant because the influence on the host by the transferase of gut bacteria is a function derived from the genome, and 2) diversity will be high because the influence on the host by the hydrolase of gut bacteria is affected by incoming dietary carbohydrates.

Molecular complexity and diversity of persistent soil organic matter

Managing and increasing organic matter in soil requires greater understanding of the mechanisms driving its persistence through resistance to microbial decomposition. Conflicting evidence exists for whether persistent soil organic matter (SOM) is molecularly complex and diverse. As such, this study used a novel application of graph networks with pyrolysis-gas chromatography-mass spectrometry to quantify the complexity and diversity of persistent SOM, defined as SOM that persists through time (soil radiocarbon age) and soil depth. We analyzed soils from the Cooloola giant podzol chronosequence across a large gradient of soil depths (0–15 m) and SOM radiocarbon ages (modern to 19,000 years BP). We found that the most persistent SOM on this gradient was highly aromatic and had the lowest molecular complexity and diversity. By contrast, fresh surface SOM had higher molecular complexity and diversity, with high contributions of plant-derived lignins and polysaccharides. These findings indicate that persisting SOM declines in molecular complexity and diversity over geological timescales and soil depths, with aromatic SOM compounds persisting longer with mineral association.

Performance of a continuous flow reactor on bio-reducing vanadium with straw

Vanadium (V) in groundwater could cause a serious threat to the environment and health. Continuous flow reactors were applied to reduce V(V) with straw being a solid carbon. The reduced efficiency of V(V) in the reactor with straw and inoculated sludge reached to 71.8%–99.9% for two months’ operation (after 44 d). However, a long-term operation with only straw was not satisfied, achieving the reduced efficiency of 39.2–66.6%. The SEM images clearly revealed some traces of straw surface by utilized by microbes, which implied that microbes had a stronger capacity to hydrolyze straw. The introducing external microbes were essential to achieve a better bio-reduction performance on V(V). Treponema (5.3%) with metal reduction ability and Prevotellaceae (3.3%) able to specifically degrade complex plant-derived polysaccharides were found to be dominant in the microbial community. Utilizing agricultural biomass can save a lot of normal carbon like acetate, which is of benefit for carbon emissions.

Polysaccharides from Discarded Stems of Trollius chinensis Bunge Elicit Promising Potential in Cosmetic Industry: Characterization, Moisture Retention and Antioxidant Activity

Unconventional polysaccharides as representative active substances from stems of Trollius chinensis Bunge (TC) were studied. Crude polysaccharides from the stems of TC (TCSP) and the petals of TC (TCPP) were extracted, and the moisture retention and antioxidation activities of both TCSP and TCPP in vitro were studied. The weight-average molar masses (Mw) of TCSP (6.07 × 105 Da) were lower than those of TCPP (9.72 × 105 Da). Glucuronic acid and xylose only existed in TCSP, and the molar ratio of galacturonic acid and mannose in TCSP was significantly higher than that in TCPP. No significant differences in moisture retention ability were found between TCSP and TCPP. The reducing capacity and dphenyl picryl hydrazinyl (DPPH) radical scavenging capacity of TCSP were slightly weaker than those of TCPP. The 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity of TCSP can be equivalent to that of TCPP. The moisture retention ability was not different between TCSP and TCPP, which are both highly homologous with traditional humectants. The antioxidation assays in vitro demonstrated that the antioxidant activity of TCSP is stronger compared to that of some plant-derived polysaccharides. The stems of TC can be a promising source of unconventional polysaccharides, which possess moisture retention and antioxidation capacities for the cosmetics industry.

Radix paeoniae alba polysaccharide attenuates lipopolysaccharide-induced intestinal injury by regulating gut microbiota.

Accumulating evidence indicated that oxidative stress is closely related to inflammation and the progression of multiple chronic diseases, which seriously threaten the host health. Currently, multiple plant-derived polysaccharides have been demonstrated to ameliorate the negative effects of oxidative stress on the host, but the potential protective effect of radix paeoniae alba polysaccharide (RPAP) on host have not been well characterized. Here, we investigated whether different doses of RPAP administration could alleviate lipopolysaccharide (LPS)-induced intestinal injury and gut microbial dysbiosis in mice. Results indicated that RPAP administration effectively alleviated LPS-induced intestinal damage in dose dependent. Additionally, amplicon sequencing showed that RPAP administration reversed the significant decrease in gut microbial diversity caused by LPS exposure and restored the alpha-diversity indices to normal levels. Microbial taxonomic investigation also indicated that LPS exposure resulted in significant changes in the gut microbial composition, characterized by a decrease in the abundances of beneficial bacteria (Lactobacillus, Alistipes, Bacillus, Rikenellaceae_RC9_gut_group, etc.) and an increase in the contents of pathogenic bacteria (Klebsiella, Helicobacter, Enterococcus, etc.). However, RPAP administration, especially in high doses, could improve the composition of the gut microbiota by altering the abundance of some bacteria. Taken together, this study demonstrated that RPAP administration could ameliorate LPS-induced intestinal injury by regulating gut microbiota. Meanwhile, this also provides the basis for the popularization and application of RPAP and alleviating oxidative stress from the perspective of gut microbiota.

Moringa oleifera leaf polysaccharides exert anti-lung cancer effects upon targeting TLR4 to reverse the tumor-associated macrophage phenotype and promote T-cell infiltration.

Tumor-associated macrophages (TAMs) participate in tumorigenesis, growth, invasion as well as metastasis by facilitating an immunosuppressive tumor microenvironment. Reversing the pro-tumoral M2 phenotype of TAMs has become a hot spot in advancing cancer immunotherapy. In the current study, the content of Moringa oleifera leaf polysaccharides (MOLP) was determined and characterized, along with the anti-cancer mechanism of MOLP studied in a Lewis lung cancer (LLC) tumor-bearing mouse model and bone marrow-derived macrophages. The monosaccharide composition and gel permeation chromatography analyses show that MOLP are mainly composed of galactose, glucose, and arabinose, with approximately 17.35 kDa average molecular weight (Mw). In vivo studies demonstrate that MOLP convert TAMs from the immunosuppressive M2 phenotype to the antitumor M1 phenotype, thus inducing CXCL9 and CXCL10 expression and increasing T-cell infiltration in the tumor. Furthermore, macrophage depletion and T cell suppression demonstrated that the tumor suppressive effect of MOLP was reliant on reprogramming macrophage polarization and T cell infiltration. In vitro studies revealed that MOLP could induce the phenotypic switch from M2 macrophages to M1 by targeting TLR4. The current study highlights that MOLP are promising anticancer plant-derived polysaccharides with potential in modulating the immune microenvironment and have a bright application prospect in the immunotherapy of lung cancer.

Progress of Studies on Plant-Derived Polysaccharides Affecting Intestinal Barrier Function in Poultry.

As natural bioactive components, plant-derived polysaccharides have many biological functions, such as anti-inflammatory, antioxidant, anticoccidial, and immunity regulation, and have been widely used in poultry production. In this review paper, firstly, the sources and structures of plant-derived polysaccharides are reviewed; secondly, the effects of plant-derived polysaccharides on the intestinal microbiome, permeability, morphology and immune function of poultry are summarized; thirdly, the potential molecular regulation mechanism of plant-derived polysaccharides on the intestinal barrier function of poultry was preliminarily analyzed. The review paper will bring a basis for the scientific utilization of plant-derived polysaccharides in the poultry industry.

Distribution of Organic Carbon Fractions in Soil Aggregates and Their Contribution to Soil Aggregate Formation of Paddy Soils

ABSTRACT Different soil organic matter fractions play different roles in governing soil aggregation. Therefore, this study determined the distribution of labile organic carbon (OC) and stable OC fractions in soil aggregates and their contribution to the soil aggregation of paddy soils in the Central Plain of Thailand. Quantitative analysis of the OC fractions in soil aggregates was determined using wet oxidation method and their changes in the chemical composition of organic compounds were investigated using FTIR spectroscopy. The results showed that the large macroaggregate (LMA: 2–8 mm) content of studied soils generally increased with increasing soil organic carbon, clay, polyvalent cations and aluminum (Al) oxides contents. Generally, both the labile OC and stable OC fractions increased with increasing aggregate size classes, suggesting a hierarchical order of soil aggregation and physical protection of organic matter against microbial decomposition. The labile OC fraction in all aggregate size classes was positively correlated with the content of LMA (r = 0.54*–0.77**), suggesting that the labile OC fraction represented a major organic cementing agent that contributed to LMA formation. FTIR analysis revealed that the labile OC fraction mainly consisted of plant-derived and microbial-derived polysaccharides. Therefore, paddy soils with higher organic cementing agent (labile OC fraction) and inorganic cementing/flocculating agents may provide a stronger intimate association of these transient binding agents, particularly the microbial-derived polysaccharides with clay mineral surfaces and metal cations/Al oxides. In turn, the greater amounts of stabilized, microbial-derived polysaccharides also efficiently promoted the formation of LMA from a combination of microaggregates.

A Mechanistic Insight on Phytoconstituents Delivering Hypoglycemic Activity: A Comprehensive Overview

Diabetes is a long-term (chronic), challenging lifestyle (metabolic) disorder in which the body cannot regulate the amount of sugar in the blood and majorly affecting endocrine system and metabolic functions. Its complications majorly affect the neurons (as developing neuropathy), kidney (as nephropathy), and eye (as retinopathy). Diabetes also results in other associated problems, such as diabetic foot ulcers, sexual dysfunction, heart diseases etc. In the traditional medicines, the search for effective hypoglycemic agents is a continuous and challenging approach. Plant-derived bioactives, including alkaloids, phenols, glycosides, anthocyanins, flavonoids, saponins, tannins, polysaccharides, and terpenes, have been established to target cellular and molecular mechanisms involved in carbohydrate metabolism. Numerous diabetic patients select the herbal or traditional medicine system as an alternative therapeutic approach along with the mainstream anti-diabetic drugs. However, due to restrictive hurdles related to solubility and bioavailability, the bioactive compound cannot deliver the requisite effect. In this review, information is presented concerning well researched phytoconstituents established as potential hypoglycemic agents for the prevention and treatment of diabetes and its associated disorders having restricted solubility and bioavailability related issues. This information can be further utilized in future to develop several value added formulation and nutraceutical products to achieve the desired safety and efficacy for the prevention and treatment of diabetes and its related diseases.

Soluble non-starch polysaccharides in fish feed: implications for fish metabolism.

Because of their unique glycosidic bond structure, non-starch polysaccharides (NSP) are difficult for the stomach to break down. NSP can be classified as insoluble NSP (iNSP, fiber, lignin, etc.) and soluble NSP (sNSP, oligosaccharides, β-glucan, pectin, fermentable fiber, inulin, plant-derived polysaccharides, etc.). sNSP is viscous, fermentable, and soluble. Gut microbiota may catabolize sNSP, which can then control fish lipid, glucose, and protein metabolism and impact development rates. This review examined the most recent studies on the impacts of various forms of sNSP on the nutritional metabolism of various fish in order to comprehend the effects of sNSP on fish. According to certain investigations, sNSP can enhance fish development, boost the activity of digestive enzymes, reduce blood sugar and cholesterol, enhance the colonization of good gut flora, and modify fish nutrition metabolism. In-depth research on the mechanism of action is also lacking in most studies on the effects of sNSP on fish metabolism. It is necessary to have a deeper comprehension of the underlying processes by which sNSP induce host metabolism. This is crucial to address the main issue of the sensible use of carbohydrates in fish feed.

A Potential Role of Plant/Macrofungi/Algae-Derived Non-Starch Polysaccharide in Colitis Curing: Review of Possible Mechanisms of Action.

Multiple in vitro and in vivo model investigations have suggested a broad spectrum of potential mechanisms by which plant/macrofungi-derived non-starch polysaccharides may play a role in the treatment of inflammatory bowel disease (IBD). This article reviews the in vivo and in vitro evidence of different plant-derived polysaccharides for IBD therapy. Their underlying mechanisms, particularly the molecular mechanisms associated with protective effects in the treatment and prevention of IDB, have been well summarized, including anti-inflammatory, epithelial barrier repair, and the regulation of intestinal flora. Emerging studies have observed the potent role of probiotics in IBD, particularly its ability to modulate gut microbiota, a well-known key factor for IBD. In summary, plant/macrofungi-derived polysaccharides have the potential to be a promising agent for the adjuvant treatment and prevention of IBD and will contribute to the design of well-designed clinical intervention trials that will ultimately improve the therapy of IBD.

Three-Dimensional Printing Properties of Polysaccharide Hydrocolloids-Unrinsed Sturgeon Surimi Complex Hydrogels.

Herein, the microstructure and mechanical properties of hydrogels consisting of unrinsed sturgeon surimi (URSS) and plant-derived polysaccharides such as κ-carrageenan (KC), konjac gum (KG), xanthan gum (XG), guar gum (GG) and sodium alginate (SA), were studied by texture analysis, rheological measurement and scanning electron microscopy (SEM). Rheological results showed that the apparent viscosity, storage modulus (G′) and loss modulus (G″) of URSS increased by addition of KC, KG, GG and SA. The gel strength of resultant surimi products fabricated with KG/URSS mixture was significantly higher than that of other groups. KG could significantly improve the hardness (44.14 ± 1.14 N), chewiness (160.34 ± 8.33 mJ) and cohesiveness (0.56 ± 0.02) of the unrinsed surimi gel. Adding SA and KC had no significant effect on the textural characteristics of printed gels. However, an apparent decrease in the relevant mechanical properties of printed hydrogels was observed when XG and GG were added into surimi. SEM indicated that the incorporation of KG and KC could further integrate the gel structure of URSS as compared to hindering the cross-linking of surimi protein by XG and GG, which were in accordance with gel strength and water-holding capacity. These results provided useful information to regulate the 3D printing performance in functionalized surimi-based material.

Removing the sporoderm from the sporoderm-broken spores of Ganoderma lucidum improves the anticancer and immune-regulatory activity of the water-soluble polysaccharide.

Plant-derived polysaccharides have demonstrated promising anti-cancer effects via immune-regulatory activity. The aim of the current study was to compare the chemical property and the anticancer effects of polysaccharides extracted from the sporoderm-removed spores of the medicinal mushroom Ganoderma lucidum (RSGLP), which removed the sporoderm completely, with polysaccharides extracted from the sporoderm-broken spores of G. lucidum (BSGLP). We found that RSGLP has a higher extraction yield than BSGLP. HPGPC and GC-MS results revealed that both RSGLP and BSGLP are heteropolysaccharides, but RSGLP had a higher molecular weight and a different ratio of monosaccharide composition than BSGLP. MTT and flow cytometry results demonstrated that RSGLP exhibited much higher dose-efficacy in inhibiting cell viability and inducing apoptosis than BSGLP in 8 cancer cell lines representing colon (HCT116 and HT29), liver (HepG2 and Huh-7), breast (MDA-MB-231 and MCF-7), and lung cancers (NCI-H460 and A549). Furthermore, RSGLP is more effective in inhibiting HCT116 and NCI-H460 xenograft tumor growth and inhibiting tumor-induced splenomegaly than BSGLP in nude mice, suggesting a better effect on regulating immunity of RSGLP. Next, we found that RSGLP is more potent in inhibiting the level of serum inflammatory cytokines in nude mice, and in inhibiting the activation of macrophage RAW264.7 and the expression of the inflammatory mediators IL-1β, TNF-α, iNOS, and COX-2 in vitro. This is the first study to compare the chemical properties, anti-cancer, and immune-regulatory effects of RSGLP and BSGLP using multiple cancer cell lines. Our results revealed that the sporoderm-removed spores of G. lucidum (RSGL) and RSGLP may serve as new anticancer agents for their promising immune-regulatory activity.

Optimization for the extraction of polysaccharides from Huidouba and their in vitro α-glucosidase inhibition mechanism

Huidouba is a kind of fungus plant that grows by spiders parasitizing tea trees at an altitude of 1500 m above Mount Emei. The bioactive polysaccharides extracted from Huidouba have been traditionally used in the treatment of diabetes in China. In this study, the optimal hot-water extraction condition of crude Huidouba polysaccharides was obtained using Box–Behnken design: the temperature of 93.7 °C, the time of 3.57 h, the liquid-to-solid ratio of 28.47 mL/g, and the yield was 0.46%. Three purified Huidouba polysaccharides (HDBPs, including HDBP-d, HDBP-1, and HDBP-2) were separated through deproteinization, ultrafiltration, and column chromatography. Then the inhibition mechanism and kinetics of HDBPs against α-glucosidase were investigated. The inhibitory activity of HDBPs on α-glucosidase was positively correlated with their concentration, and their mechanism of quenching fluorescence was ascertained to be the static type induced by the formation of HDBPs-α-glucosidase complex. HDBP-d and HDBP-2 inhibited the activity of α-glucosidase in a reversible competitive-type manner while HDBP-1 was a noncompetitive-type inhibitor. The inhibitory activities of HDBPs on α-glucosidase correlated inversely with temperature in most cases, and showed weaker inhibitory activity at extreme acidic or alkaline conditions. These findings highlight the efficacy, kinetics and mechanism of HDBPs inhibiting α-glucosidase in vitro. The study provided a replaceable approach for chemical inhibitors of α-glucosidase with natural fungus plant extracts, and suggested the theoretical basis that the plant-derived polysaccharides with glucosidase inhibition effects were applied in medicines.

Ruminal Microbiota Determines the High-Fiber Utilization of Ruminants: Evidence from the Ruminal Microbiota Transplant.

ABSTRACTThe rumen, which contains a series of prokaryotes and eukaryotes with high abundance, determines the high ability to degrade complex carbohydrates in ruminants. Using 16S rRNA gene sequencing, we compared the ruminal microbiota of dairy goats with that in the foregut and colon of mice and found more Bacteroides identified in the rumen, which helps ruminants to utilize plant-derived polysaccharides, cellulose, and other structural carbohydrates. Furthermore, high-fiber diets did not significantly increase intestinal fiber-degrading bacteria in mice, but did produce higher levels of ruminal fiber-degrading bacteria in dairy goats. Through rumen microbe transplantation (RMT), we found that rumen-derived fiber-degrading bacteria can colonize the intestines of mice to exert their fiber-degrading function, but their colonization efficiency is affected by diet. Additionally, the colonization of these fiber-degrading bacteria in the colon may involve higher content of butyrate in the colon, protecting the colonic epithelial barrier and promoting energy metabolism. Overall, the fiber degradation function of rumen bacteria through RMT was verified, and our results provide new insights into isolating the functional and beneficial fiber-degrading bacteria in the rumen, providing a theoretical basis for the role of dietary fiber in intestinal health.IMPORTANCE Ruminants have a powerful progastric digestive system that converts structural carbohydrates into nutrients useful to humans. It is well known that this phenomenon is due to the fact that the rumen of ruminants is a natural microbial fermenter, which can ferment structural carbohydrates such as cellulose and hemicellulose and transform them into volatile fatty acids to supply energy for host. However, monogastric animals have an inherent disadvantage in utilizing fiber, so screening rumen-derived fiber-degrading bacteria as a fermentation strain for biological feed is needed in an attempt at improving the fiber digestibility of monogastric animals. In this study, a ruminal microbiota transplant experiment from goats to mice proves that ruminal microbiota could serve as a key factor in utilization of high-fiber diets and provides a new perspective for the development of probiotics with fiber degradation function from the rumen and the importance of the use of prebiotics during the intake of probiotics.