Monosaccharide Components Research Articles

The Influence and Mechanisms of Natural Plant Polysaccharides on Intestinal Microbiota-Mediated Metabolic Disorders.

Natural plant polysaccharides are renowned for their broad spectrum of biological activities, making them invaluable in both the pharmaceutical and food industries. Their safety, characterized by low toxicity and minimal side effects, coupled with their potential therapeutic properties, positions them as crucial elements in health-related applications. The functional effectiveness of these polysaccharides is deeply connected to their structural attributes, including molecular weight, monosaccharide components, and types of glycosidic bonds. These structural elements influence how polysaccharides interact with the gut microbiota, potentially alleviating various metabolic and inflammatory disorders such as inflammatory bowel disease, diabetes, liver-associated pathologies, obesity, and kidney diseases. The polysaccharides operate through a range of biological mechanisms. They enhance the formation of short-chain fatty acids, which are pivotal in keeping intestinal health and metabolic balance. Additionally, they strengthen the intestinal mucosal barrier, crucial for deterring the ingress of pathogens and toxins into the host system. By modulating the immune responses within the gut, they help in managing immune-mediated disorders, and their role in activating specific cellular signaling pathways further underscores their therapeutic potential. The review delves into the intricate structure-activity relationships of various natural polysaccharides and their interactions with the intestinal flora. By understanding these relationships, the scientific community can develop targeted strategies for the use of polysaccharides in therapeutics, potentially leading to innovative treatments for a range of diseases. Furthermore, the insights gained can drive the advancement of research in natural polysaccharide applications, providing direction for novel dietary supplements and functional foods designed to support gut health and overall well-being.

Structural identification and anti-stomatitis activity of one arabinose-rich polysaccharide from Rehmannia glutinosa

The anti-stomatitis effects of polysaccharides from natural sources have been relatively few reported. In this study, a polysaccharide RGP-5 A was isolated and purified from Rehmannia glutinosa, and its structural characteristics and anti-stomatitis activity were evaluated. The molecular weight of RGP-5 A was 1.35 × 105 Da, containing ten monosaccharides, of which arabinose was the main monosaccharide component. Methylation and NMR analysis showed that RGP-5 A contained uronic acid, pyranoside and α-glycosidic bonds. The main glycosidic bond connection mode of RGP-5 A polysaccharide was 4-Gal(p)-UA; the backbone of RGP-5 A is mainly composed of →4)-β-d-Galp(1 → and →4)-α-d-GalpA(1 → residue, and the terminal signal is identified as T-α-L-Araf (1→. Furthermore, RGP-5 A polysaccharide could significantly reduce the secretion levels and protein expression levels of human TNF-α, IL-6, IL-8, and IL-1β in LPS induced HGFs. The findings indicate that this natural polysaccharide from Rehmannia glutinosa has the potential to treat stomatitis.

Multiple fingerprinting and chromatography-immunoreactivity relationship of polysaccharides from Dioscorea opposite Thunb

The quality evaluation of Dioscorea opposite Thunb. mainly focuses on determining water-soluble contents. Polysaccharides are now recognized as the significant constituents of yam with activities such as immune enhancement, and it is necessary to use polysaccharides as an indicator for quality control of yam in this study. Sixty batches of yam polysaccharides were obtained by conventional hot water extraction and analysis for their physicochemical properties and structure. The results showed the functional groups (four shared peaks including 3500–3300 cm−1) and molecular weights (2.06 × 103 Da-2.28 × 103 Da). The PMP-HPLC fingerprints calibrated 5 familiar peaks, and the relative retention times of each characteristic peak to the Glc peak (S peak) were 0.47 (Man), 0.86 (GalA), 1.00 (Glc), 1.13 (Gal), 1.24 (Ara), Glc and Gal, which were the main differentiated monosaccharide components in the HPLC fingerprinting of YPs. This study provided a preliminary data reference for quality control of YPs.

Optimization of polysaccharide extraction from pumpkin seeds using ultrasonic-assisted enzymatic method

This study aimed to optimize the extraction process of polysaccharides from seed pumpkins. Following initial single-factor experiments, the extraction process using ultrasonic-assisted enzymatic method was optimized through orthogonal experiments. Further optimization of extraction conditions was conducted using response surface methodology with Box-Behnken design, ultimately identifying the optimal extraction parameters. Additionally, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, monosaccharide component analysis, polysaccharide molecular weight measurement, and NMR analysis were performed. Results indicated that ultrasonic-assisted enzymatic extraction significantly enhanced the yield of polysaccharide, reaching up to 43.65%. The findings confirm that the combined use of enzymatic hydrolysis and ultrasonication is an effective strategy for polysaccharide extraction.

Structural and functional properties of polysaccharides extracted from three Dioscorea species

Dioscorea has a history spanning over 2000 years for both medicinal and edible purposes in China. It contains rich polysaccharides, which are frequently utilized as thickening and stabilizing agents in the food industry. However, there has been relatively little focus on polysaccharides from common Dioscorea species besides D. opposita, such as D. alata and D. esculenta. In this study, non-starch crude polysaccharides were isolated from D. opposita (BD), D. alata (WC), and D. esculenta (GZ). Their structures, physicochemical compositions, and functional properties were characterized and compared. The results indicated three polysaccharides all exhibited characteristic peaks of polysaccharides and possessed triple-helix structures. The Glc (36.78–83.90 %), Man (6.71–26.68 %), and GalA (8.54–10.22 %) were identified as the primary monosaccharide components. In terms of functionality, three polysaccharide solutions demonstrated non-Newtonian flow characteristics and displayed commendable thermal stability. It is worth noting that the antioxidant and emulsifying properties of polysaccharides isolated from D. opposita (BD) and D. alata (WC) were superior to those of D. esculenta (GZ), making them more suitable for use as antioxidants and stabilizers. By comparing polysaccharides derived from different Dioscorea species, this study provides valuable insights into the food, cosmetic, and pharmaceutical industries based on the unique properties of these different polysaccharides.

A method for the quantitative analysis of Lycium barbarum polysaccharides (LBPs) using Fourier-transform infrared spectroscopy (FTIR): From theoretical computation to experimental application

Lycium barbarum polysaccharides (LBPs) is one of the most important active substances in Lycium barbarum (LB). It is a challenge to quantitatively determine the content due to their complex structures and lack of suitable reference standard in practice. In this study, a quantitative analysis method of LBPs in LB was established based on Fourier-transform infrared spectroscopy (FTIR). The stretching vibration of CO on the pyranose ring of saccharide at 921 cm−1 was selected as the characteristic absorption band by theoretical calculation, which can’t be impacted by the preparation methods and interfered by the component monosaccharides. The molecular weight CRM of dextran (Mw 63.3 kDa) served as the reference standard. The introducing internal standard (KSCN) can obtain a good precision (RSD = 1.10 %) and effectively compensate for the analysis errors caused by the environment, quality loss and uneven distribution during the tablet pressing processes. The methodological verification suggested that the method had good accuracy according to the recovery rate (96.61 %–105.45 %) and the blank recovery (92.39 %–99.37 %), respectively. The LOD and LOQ of CRMD were 0.10 mg and 0.32 mg, respectively. The polysaccharide content of LB from 24 different regions (0.50–2.54 %) and 10 batches of LB extracts (7.09–10.56 %) determined by the developed method less than the ones using phenol–sulfuric acid assay (1.95 %–4.83 % for LB and 9.83–15.53 % for extracts, respectively). The established method based on FTIR could be served as a supplement to phenol–sulfuric acid assay and a rapid quantitative assay for polysaccharides products. In additional, this study provided a new idea for the quantitative analysis of plant polysaccharides.

Determination of Antioxidant and Antimicrobial Activities of Cell-Free Supernatant (CFSKC27L) and Exopolysaccharide (EPSKC27L) obtained from Ligilactobacillus salivarius KC27L

Twenty-six lactic acid bacteria were obtained from poultry feces sampled located in the Ankara area (Türkiye) and belong to the Lactobacillus genus according to the results obtained by biochemical methods. This study screened these isolates for exopolysaccharides (EPS) production. EPS production was detected in these isolates, varying from 8 mg L-1 to 353 mg L-1. The highest EPS-producing isolate (KC27L) was selected for further studies. The isolate was identified as Ligilactobacillus salivarius by 16S rRNA analysis. Furthermore, the anti-biofilm and antioxidant abilities of the cell-free supernatant (CFSKC27L) and different concentrations (0.5 mg L-1 and 1 mg L-1) of EPS belonging to the KC27L strain (EPSKC27L) that exhibited high EPS production were determined. CFSKC27 and different concentrations (0.5 mg L-1 and 1 mg mL-1) of EPSKC27L determined the anti-biofilm impact on Escherichia coli ATCC 11229, Enterococcus faecalis ATCC 29212, and Staphylococcus aureus EB-1. The highest anti-biofilm effect in 1 mg mL-1 EPSKC27L was detected at E. coli ATCC 11229 with 87 % inhibition. Three different methods (1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating and superoxide anion radical scavenging activity) designated antioxidant activity. The highest 1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating, and superoxide anion radical scavenging activity were found in 1 mg mL-1 EPSKC27L (79.6%, 24.9%, and 61.6%, respectively). Both anti-biofilm and antioxidant activities of 1 mg mL-1 EPSKC27L were higher than postbiotic. Finally, its molecular characterization was done following the partial purification of the EPSKC27L. The EPSKC27L has two fractions with molecular weights of 1.6x103 and 6.4 x104 Da. Monosaccharide components of EPSKC27L were found to be glucose (53.1%), fructose (18.5%), arabinose (14.6%) and mannose (13.8%). CFSKC27L and EPSKC27L obtained from L. salivarius can be antioxidants and anti-biofilm agents.

Structural characterization and prebiotic activity of oligo-galacturonic acids from Osmunda japonica Thunb

An oligosaccharide, WOJP-AOS-b, with a molecular size of 1.8 kDa, was obtained through enzymatic hydrolysis of Osmunda japonica Thunb polysaccharides (WOJP-A). The structural characteristics of WOJP-AOS-b were elucidated using Fourier transform-infrared spectroscopy (FT-IR), Ultraviolet (UV) spectroscopy, Nuclear magnetic resonance (NMR) spectroscopy, and Eelectrospray ionization tandem mass spectrometry (ESI-MS/MS). Structural analysis revealed that galacturonic acid (GalpA) was the predominant monosaccharide component of WOJP-AOS-b, accounting for 90.91% of the total composition. FT-IR and NMR analyses confirmed that WOJP-AOS-b possesses a linear structure comprised of α-1,4-linked GalpA residues. MS/MS results indicated that WOJP-AOS-b consists of α-1,4-linked oligo-galacturonic acids with degrees of polymerization ranging from 2 to 6 (DP 2–6). Moreover, in vitro probiotic activity assays demonstrated that WOJP-AOS-b exerted beneficial effects on intestinal microbiota, particularly Bifidobacterium adolescentis ATCC 15703 and Bifidobacterium breve 689b. WOJP-AOS-b enhanced the optical density, short-chain fatty acid (SCFA) content, and lactic acid content in the culture medium. Furthermore, 16S rRNA analysis suggested that WOJP-AOS-b exhibits potential for treating obesity and inhibiting pathogenic bacteria, indicating its promising applications as a prebiotic.

Novel quinazolin-6-yl Isoindolinone: Altering polysaccharide chemstructure for antibacterial efficacy against Staphylococcus aureus

The ongoing development of novel strategies to combat Staphylococcus aureus and eliminate its biofilm formation has gained significant attention for human health. Antibiotic-resistant S. aureus necessitates the development of novel antibacterial agents with new mechanism of action. This study introduced a promising recently synthesized quinazolin-6-yl isoindolinone (IQE-X1), which exhibited potent antibacterial and antibiofilm efficacy with average median inhibitory concentration (IC50) of 3.37 μg mL−1 and minimal inhibitory concentration (MIC) of 12.5 μg mL−1, coupled with its ability to reduce cell surface hydrophobicity. IQE-X1 dose-dependently decreased extracellular polysaccharides (EPS) and its component monosaccharides, including rhamnose, arabinose, glucosamine, galactose, glucose, xylose, mannose, and ribose, accompanied by an increase in capsular polysaccharides (CP) and its individual monosaccharides, especially glucosamine. IQE-X1 demonstrated specificity in modulating the structural profiles of EPS and CP by altering the compositional ratios of their component monosaccharides. The potential mechanism of polysaccharide modulation was preliminarily elucidated through the response of β-N-acetylaminoglucosidase to IQE-X1 and their direct binding interaction. These findings provide new insights into the potential manipulation of the chemstructure of these biologically important macromolecules, EPS and CP, and highlight the antibacterial potential of IQE-X1 as a polysaccharide modulator for the development of more effective polysaccharide-targeted strategies against S. aureus.

Structure identification and activity evaluation of polysaccharide from Codonopsis pilosula (C. pilosula nannf. Var. modesta (nannf.) L. T. Shen)

Codonopsis pilosula is a medicinal plant with properties related to food, and the antioxidant and hypoglycemic components of its natural polysaccharides, as well as their related mechanisms, have not been fully understood. This study examined the physicochemical properties and structure of C. pilosula polysaccharide (WCP) using an orthogonal extraction method involving hot water-alcohol precipitation, high-resolution spectroscopy, and microscopic imaging technology. The antioxidant and hypoglycemic activities of the polysaccharides were assessed. Six fractions (WCP1, WCP2, WCP3, WCP4, WCP5, and WCP6) were identified through purification using a DEAE-cellulose column and Sephadex G-100 gel column. Mannose, glucose, and arabinose were identified as the primary monosaccharide components of WCPs through Gas Chromatography (GC). The polysaccharide exhibited a crystal structure composed of irregularly entangled pyranose particles of WCPs as revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The polysaccharide decomposed into smoother triple-helix fibrous flocs as indicated by Congo red analysis and circular dichroism analysis (CD). The antioxidant capacity of the polysaccharides against various free radicals was evaluated, with WCP4 demonstrating a significant reducing capacity. Moreover, WCP3 and WCP5 displayed notable inhibition rates of α-amylase and α-glucosidase, respectively. Molecular docking studies indicated the interaction of WCP5 with two enzymes, forming multiple hydrogen bonds through specific amino acids. In the gromacs simulation, both composite systems maintained a steady state in terms of root mean square deviation (RMSD), root mean square fluctuation (RMSF), and radius of gyration, providing strong support for their potential as a reference for the developing novel therapeutic approaches to diabetes.

Eleven new glycosidic acid methyl esters from the crude resin glycoside fraction of Ipomoea alba seeds.

Resin glycosides are characteristic of plants of the Convolvulaceae family and are well-known purgative ingredients in crude drugs, such as Rhizoma Jalapae, Orizaba Jalapa Tuber, and Pharbitidis Semen, which are used in traditional medicine and derived from plants belonging to this family. Isolated resin glycosides have demonstrated diverse biological activities, including antibacterial, ionophoric, anti-inflammatory, antiviral, and multidrug-resistance-modulating properties, as well as cytotoxicity against cancer cells. These compounds consist of hydroxyl fatty acid oligoglycosides (glycosidic acids), with portions of the saccharide moieties acylated with some organic acids to form the core structure. This study investigated the glycosidic acid components of a crude resin glycoside fraction obtained from a methanolic extract of Ipomoea alba L. seeds (Convolvulaceae). Eleven new glycosidic acid methyl esters and one known methyl ester were isolated from a glycosidic acid fraction treated with trimethylsilyldiazomethane in hexane. Their structures were determined using acidic hydrolysis and electrospray ionization-time of fight mass spectrometry and NMR spectral analyses. These compounds are penta-, tetra-, or triglycosides, with methyl 11S-hydroxytetradecanoate or methyl 11S-hydroxyhexadecanoate as the aglycone. Although D-quinovose and L-rhamnose are common monosaccharide components, the remaining monosaccharides are D-glucose, D-xylose, or D-fucose. The crude resin glycoside fraction showed non-negligible cytotoxicity against HL-60 human promyelocytic leukemia cells.

Structural Characterization and Biological Properties Analysis of Exopolysaccharides Produced by Weisella cibaria HDL-4.

An exopolysaccharide (EPS)-producing strain, identified as Weissella cibaria HDL-4, was isolated from litchi. After separation and purification, the structure and properties of HDL-4 EPS were characterized. The molecular weight of HDL-4 EPS was determined to be 1.9 × 10⁶ Da, with glucose as its monosaccharide component. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analyses indicated that HDL-4 EPS was a D-glucan with α-(1→6) and α-(1→4) glycosidic bonds. X-ray diffraction (XRD) analysis revealed that HDL-4 EPS was amorphous. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations showed that HDL-4 EPS possesses pores, irregular protrusions, and a smooth layered structure. Additionally, HDL-4 EPS demonstrated significant thermal stability, remaining stable below 288 °C. It exhibited a strong metal ion adsorption activity, emulsification activity, antioxidant activity, and water-retaining property. Therefore, HDL-4 EPS can be extensively utilized in the food and pharmaceutical industries as an additive and prebiotic.

Effect of solid-state co-fermentation on the structural characteristics and bioactivities of polysaccharides in the medicinal residues of GastrodiaGanoderma

To investigate the effect of solid-state co-fermentation on the structural characteristics and bioactivities of polysaccharides in the medicinal residues of Gastrodia Ganoderma (RGG), two kinds of polysaccharides were isolated and purified from unfermented RGG and fermented RGG, named RP and FRP, respectively. The results showed that molecular weight of FRP decreased than RP and its monosaccharide composition changed significantly. RP was mainly composed of Glucose (66.46%) and Galactose (22.83%) while the main monosaccharide components of FRP was galacturonic acid (65.67%). Fermentation caused the surface morphology of FRP to become fragmented and loose, and increased its in vitro antioxidant activity. Both RP and FRP could repair cell damage, reduce the secretion of reactive oxygen species, and protect RAW 264.7 cells from LPS-induced inflammation. Molecular docking results indicated that monosaccharide structures in FRP had stronger binding energy for inflammatory markers. This study may provide theoretical reference for the high-value utilization of Chinese herbal residues.

Analysis of spatiotemporal changes mechanism of cell wall biopolymers and monosaccharide components in kiwifruit during Botryosphaeria dothidea infection

To further reveal the interaction mechanism between plants and pathogens, this study used confocal Raman microscopy spectroscopy (CRM) combined with chemometrics to visualize the biopolymers distribution of kiwifruit cell walls at different infection stages at the cellular micro level. Simultaneously, the changes in the content of various monosaccharides in fruit were studied at the molecular level using high-performance liquid chromatography (HPLC). There were significant differences in the composition of various nutrient components in the cell wall structure of kiwifruit at different infection times after infection by Botryosphaeria dothidea. PCA could cluster samples with infection time of 0–9 d into different infection stages, and SVM was used to predict the PCA classification results, the accuracy >96 %. Multivariate curve resolution-alternating least squares (MCR-ALS) helped to identify single substance spectra and concentration signals from mixed spectral signals. The pure substance chemical imaging maps of low methylated pectin (LMP), high methylated pectin (HMP), cellulose, hemicellulose, and lignin were obtained by analyzing the resolved concentration data. The imaging results showed that the lignin content in the kiwifruit cell wall increased significantly to resist pathogens infection after the infection of B. dothidea. With the development of infection, B. dothidea decomposed various substances in the host cell walls, allowing them to penetrate the interior of fruit cells. This caused significant changes in the form, structure, and distribution of various chemicals on the fruit cell walls in time and space. HPLC showed that glucose was the main carbon source and energy substance obtained by pathogens from kiwifruit during infection. The contents of galactose and arabinose, which maintained the structure and function of the fruit cell walls, decreased significantly and the cell wall structure was destroyed in the late stage of pathogens infection. This study provided a new perspective on the cellular structure changes caused by pathogenic infection of fruit and the defense response process of fruit and provided effective references for further research on the mechanisms of host-pathogen interactions in fruit infected by pathogens.

Enzyme and Microwave Coassisted Extraction, Physicochemical Properties, and Antioxidant Activity of Polysaccharides from Baijiu Distillers' Grains

AbstractBaijiu distillers' grain is a solid waste after the fermentation of grains, and their high added value and deep processing and utilization require further study. This study uses the enzyme and microwave coassisted method to extract Baijiu distillers' grain polysaccharides (DGPs). Through optimization of the single‐factor test and response surface methodology (RSM), the optimal conditions are solid–liquid ratio 1:30, enzyme time 50 min, enzyme temperature 50 °C, enzyme pH 5.0, microwave time 6 min, and microwave power 480 W, with a maximum DGP yield of 3.98% ± 0.03. DGP is purified by DEAE‐Sepharose cellulose ion exchange chromatography to obtain four fractions, namely DGP‐1, DGP‐2, DGP‐3, and DGP‐4; the molecular weights are 2224.05, 90.99, 1478.16, and 346.19 kDa, respectively, and the main monosaccharide components are Man and Glc. The antioxidant assay shows that the four kinds of DGPs have different free radical scavenging capacities, among which DGP‐2, DGP‐3, and DGP‐4 have good antioxidant activities. Therefore, DGP can be used as a potential natural antioxidant.

Developing a new ethylene glycol/H2O pretreatment system to achieve efficient enzymatic hydrolysis of sugarcane bagasse cellulose and recover highly active lignin: Countercurrent extraction

Improving pretreatment efficiency is a critical premise in achieving efficient biomass conversion, and obtaining high-performance natural polymers is the guarantee of high-value conversion of biomass. In this study, a new pilot-scale continuous countercurrent pretreatment reaction unit about ethylene glycol-alkali solution was designed for pretreating sugarcane bagasse in order to achieve efficient separation of the three major components of lignocellulose when expanding the scale of pretreatment, reduce lignin deposition on the fiber surface, and obtain highly active lignin and excellent enzymatic hydrolysis efficiency of cellulose. X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), brunauer-emmett-teller (BET) and scanning electron microscope (SEM) methods are used to analyze the structural properties of sugarcane bagasse before and after pretreatment, and high-performance liquid chromatography (HPLC) is used to analyze the monosaccharide components in the enzymatic solution. In addition, the structural properties of the recovered lignin are analyzed by gel permeation chromatography (GPC), 31P NMR and 2D-HSQC-NMR methods. The results indicate that the system can gain a high cellulose recovery of 92.99% along with a lignin removal of 95.33%, and recovered lignin has low lignin carbohydrate complexes, low condensation, and rich in phenolic hydroxyl groups for 1.95 mmol/g. Meanwhile, the countercurrent pretreatment system can effectively reduce the deposition of lignin on the cellulose surface, which is evidently superior to the non-countercurrent pretreatment and facilitates the efficiency of enzymatic saccharification of substrate, achieving a high glucose yield of 99% as well as a total sugar yield of 91.11%. The method efficiently separates biomass in a green manner, and solid residues are easily hydrolyzed, showing potential for industrial-scale production.

The Utilization by Bacteroides spp. of a Purified Polysaccharide from Fuzhuan Brick Tea.

In the present study, four Bacteroides species that could degrade Fuzhuan brick tea polysaccharide-3 (FBTPS-3) were isolated from human feces and identified to be Bacteroides ovatus, B. uniformis, B. fragilis and B. thetaiotaomicron. The four Bacteroides species showed growth on FBTPS-3 as the carbon source, and B. ovatus showed the best capability for utilizing FBTPS-3 among the four species since B. ovatus could utilize more FBTPS-3 during 24 h fermentation. Moreover, the four Bacteroides species could metabolize FBTPS-3 and promote the production of acetic, propionic and isovaleric acids. Transcriptome analysis of B. ovatus revealed that 602 genes were up-regulated by FBTPS-3, including two carbohydrate-active enzyme clusters and four polysaccharide utilization loci (PULs). The PUL 1 contained GH28 family that could hydrolyze rhamnogalacturonan and other pectic substrates, which was in line with our previous work that rhamnose and galacturonic acid were the main component monosaccharides of FBTPS-3. Collectively, the results suggested that FBTPS-3 could be utilized by Bacteroides spp., and it might be developed as a promising prebiotic targeting Bacteroidetes in intestinal environment.

Pleurotus eryngii polysaccharides alleviate aflatoxin B1-induced liver inflammation in ducks involving in remodeling gut microbiota and regulating SCFAs transport via the gut-liver axis

Aflatoxin B1 (AFB1) is one of the most widespread contaminants in agricultural commodities. Pleurotus eryngii (PE) is widely used as a feed additive for its anti-inflammatory properties, and its major active substance is believed to be polysaccharides. This study aims to explore the underlying mechanism of dietary PE polysaccharides alleviating AFB1-induced toxicity in ducks. The major monosaccharide components of PE polysaccharides were identified as glucose, mannose, galactose, glucuronic acid, and fucose. The results showed that dietary PE polysaccharides could alleviate liver inflammation, alleviate intestinal barrier dysfunction, and change the imbalanced gut microbiota induced by AFB1 in ducks. However, PE polysaccharides failed to exert protective roles on the liver and intestine injury induced by AFB1 in antibiotic-treated ducks. The PE + AFB1-originated microbiota showed a positive effect on intestinal barrier and inflammation, the SCFAs transport via the gut-liver axis, and liver inflammation compared with the AFB1-originated microbiota in ducks. These findings provided a possible mechanism that PE polysaccharides alleviated AFB1-induced liver inflammation in ducks by remodeling gut microbiota, regulating microbiota-derived SCFAs transport via the gut-liver axis, and inhibiting inflammatory gene expressions in the liver, which may provide new insight for therapeutic methods against AFB1 exposure in animals.

Identification and characterization of organic and glycosidic acids in the crude resin glycoside fraction of Ipomoea alba seeds

Resin glycosides act as laxatives in crude drugs derived from plants of the Convolvulaceae family. These compounds have exhibited antibacterial, ionophoric, anti-inflammatory, antiviral, and multidrug resistance-modulating properties, as well as cytotoxicity against cancer cells. This study investigated the organic acid, hydroxyl fatty acid, monosaccharide, and glycosidic acid components of the crude resin glycoside fraction obtained from the methanol extract of Ipomoea alba L. (Convolvulaceae) seeds, which was subjected to alkaline and acidic hydrolysis. The alkaline hydrolysis yielded acetic, isobutyric, (E)-2-methylbut-2-enoic, and 2S-methyl-3S-hydroxybutyric acids as organic acid components, along with a glycosidic acid fraction. The acidic hydrolysis of the glycosidic acid fraction resulted in the isolation of 11S-hydroxytetradecanoic and 11S-hydroxyhexadecanoic acids as hydroxyl fatty acid components, as well as d-glucose, d-quinovose, d-fucose, d-xylose, and l-rhamnose as monosaccharide components. In addition, 10 new glycosidic acid methyl esters were isolated from the glycosidic acid fraction treated with trimethylsilyldiazomethane–hexane, along with one known glycosidic acid methyl ester. Of these, eight compounds contained new glycans. Four of these compounds were unusual natural glycosides with four glycosidic linkages to one monosaccharide. Their structures were determined using MS and NMR spectral analyses, which provided valuable insights into the unique glycosidic composition of I. alba seeds.

Effects of priming glycosyltransferase genes cps 2E and cps 4E on the exopolysaccharide biosynthesis by Lactiplantibacillus plantarum YM-4-3 strain

Microbial exopolysaccharides (EPS) have various physiological functions such as antioxidant, anti-tumor, cholesterol lowering, and immune regulation. However, improving traditional fermentation conditions to increase the production of EPS from Lactiplantibacillus plantarum (L. plantarum) is limited. In this study, we aimed to better improve EPS production and physiological functions of L. plantarum YM-4-3 strain by overexpressing and knocking out the priming glycosyltransferase genes cps 2E and cps 4E for the first time. As a result, the EPS production of the overexpression strain was 30.15 %, 26.84 % and 36.29 % higher than WT, respectively. The EPS production of the knockout strain was significantly lower than that of the WT. At the same time, transcriptome data showed that the gene expression levels of each experimental strain had changed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways found that the glycolysis/gluconeogenesis pathway had the highest gene enrichment in the metabolic pathway. The monosaccharide components of the EPS of each experimental strain were different from those of the WT and the EPS of the experimental strain showed stronger activity against oxidation. In conclusion, this study contributes to the efficient production and application of L. plantarum EPS and helps to understand the mechanism of EPS regulation in L. plantarum.