A polysaccharide NAP-3 from Naematelia aurantialba: Structural characterization and adjunctive hypoglycemic activity

Structural characterization of two novel heteropolysaccharides from Catharanthus roseus and the evaluation of their immunological activities

Catharanthus roseus, a plant with significant therapeutic value in Chinese folk medicine, contain numerous secondary metabolites. However, the primary metabolites, specifically polysaccharides which might play an important role in immunotherapy, have received limited attention. In the present study, two novel polysaccharides, designated as CRPS-1 and CRPS-2, were isolated from C. roseus. The structures of CRPS-1 and CRPS-2 were characterized using a combination of HPSEC, HPLC, IR, GC-MS, 1D NMR and 2D NMR. Both CRPS-1 and CRPS-2 were identified as homogeneous heteropolysaccharides. Additionally, the weight-average molecular weight of CRPS-2 was lower than that of CRPS-1. The backbone of CRPS-1 was composed of 1,3-α-L-Araf, 1,5-α-L-Araf, 1,3,5-α-L-Araf, 1,3,4-α-L-Rhap, 1,3-α-D-Galp, 1,3,4-α-D-Galp, 1,4-β-D-Manp, and side chains comprised of T-α-L-Araf, T-β-D-Manp, and β-D-Glcp-(1 → 3)-α-D-Galp-(1 → 3) -α-L-Rhap-(1→. CRPS-2 mainly consisted of 1,3-α-D-Galp, 1,3,4-α-D-Galp, 1,6-β-D-Manp, 1,5-α-L-Araf, 1,3,5-α-L-Araf, 1,3-α-L-Rhap and 1,3,4-α-L-Fucp with complex branching structures. Furthermore, CRPS-2 could significantly enhance proliferation and phagocytosis, as well as the secretion of cytokines in RAW264.7 cells. It demonstrated potent immunoregulatory activity by activating the MAPK/Akt/NF-κB signaling pathways. In summary, the utilization of galactose-enriched and low-molecular-weight polysaccharides exhibits great potential in the advancement of innovative functional foods that may provide health benefits.

Structural characterization and antioxidant activity evaluation of a polysaccharide from pink Auricularia cornea

An acidic polysaccharose (YL-D2N2) was isolated from crude polysaccharides of pink Auricularia cornea and characterized for its structural and antioxidant properties. YL-D2N2 consists of fucose, galactose, glucose, xylose, mannose and glucuronic acid in a molar ratio of 0.85: 1.50: 4.44: 27.52: 46.56: 19.13. It has a number-average molecular weight of about 52.811 kDa and a weight-average molecular weight of about 135.457 kDa. Structural characterization showed that YL-D2N2 consists of nine residues (Xylp-(1→, GlcpA-(1→, →2)-Xylp-(1→, →3)-Galp-(1→, →3)-Manp-(1→, →4)-GlcpA-(1→, →2,3)-Manp-(1→, →3,4)-Glcp-(1→, →3,6)-Manp-(1→), with a backbone of →3)-β-D-Manp-(1→, →2,3)-α-D-Manp-(1→, →3,6)-α-D-Manp-(1 → and side chains containing β-D-Xylp-(1 → and α-D-GlcpA-(1→. Notably, YL-D2N2 exhibits significant radical scavenging activity for superoxide anions, reaching 50.82 ± 0.64 % at a concentration of 3.2 mg/mL. Overall, YL-D2N2 exhibits a unique chemical structure and specialized applications for targeting superoxide anion radicals, providing valuable insights for further exploration of its structure-activity relationship.

Preliminary characterization of Ramaria botrytoides polysaccharide RB-P1-1 and analysis of its hypoglycemic effects by altering the gut microbiota and metabolites in mice with type 2 diabetes mellitus

Gut microbiota has a symbiotic relationship with the host and is closely linked to the development of type 2 diabetes mellitus (T2DM). Polysaccharides are natural bioactive compounds with beneficial effects on T2DM; however, the mechanisms underlying their effects remain unclear. This study investigated the hypoglycemic effects of a purified polysaccharide, RB-P1-1, from Ramaria botrytoides and assessed its association with gut microbiota and metabolite changes using 16S rDNA sequencing and liquid chromatography-mass spectrometry, respectively. Hypoglycemic effects were evaluated after microbial community restoration via fecal microbiota transplantation. RB-P1-1 significantly improved hyperglycemia profiles and reshaped gut microbiota, increasing the abundance of Alistipes, Bacteroides, Ruminococcus, Odoribacter, Akkermansia, and Turicibacter. RB-P1-1 modulated microbiota metabolites associated with hypoglycemic effects, including pyridoxamine, L-histidine, quercetin, 3-phosphonopropionic acid, oleoylethanolamide, 3-ketocholanic acid, 4-phenylbutyric acid, LysoPC(P-16:0/0:0), LysoPC(18:2), and short-chain fatty acids, and altered various metabolic pathways involved in T2DM development. Gut microbiota that showed altered abundance were correlated with metabolites that showed altered concentration. Gut microbiota isolated from the RB-P1-1-treated group alleviated the symptoms associated with T2DM. These results suggest RB-P1-1 is an effective active ingredient in the treatment of T2DM by modulating gut microbiota and metabolites.

Polysaccharides of Floccularia luteovirens regulate intestinal immune response, and oxidative stress activity through MAPK/Nrf2/Keap1 signaling pathway in immunosuppressive mice

This study explores the novel immunomodulatory effects of polysaccharides from the rare Floccularia luteovirens, a fungus with significant potential yet unexplored bioactive components, traditionally used in Tibetan medicine. This study employs a wide array of analytical techniques, including HPGPC, HPLC, western blotting, ELISA, and 16S rRNA gene sequencing, to comprehensively investigate FLP1's effects. The main structure of FLP1 was characterized by IF-TR and NMR spectrometry. The structural backbone of FLP1 was →3,6)-β-D-Glcp-(1 → and →2,3)-α-D-Manp-(1→. After immunosuppressed mice treated with FLP1, the findings demonstrated that FLP1 stimulated the production of secretory sIgA and secretion of cytokines (IL-4, TNF-α, and IFN-γ) in the intestine of Cy-treated mice, resulting in the activation of the MAPK pathway. Additionally, FLP1 protected oxidative stress by triggering Nrf2/Keap1 pathways and antioxidation enzymes (SOD, MDA, T-AOC, CAT, and GSH-Px). It also enhanced the intestinal barrier function by regulating the villous height ratio and expression of tight-junction protein. Furthermore, FLP1 remarkably reversed the gut microbiota dysbiosis in immunosuppressed mice by increasing the abundance of Oscilliospiraceae, and Lachnospiraceae, and altered the fecal metabolites by increasing LysoPE (0:0/18:0); 0:0/16:0; 18:1(11Z)/0:0, LysoPG (16:0/0:0), LysoPG 18:1 (2n) PE (14:0/20:1), echinenone, 2-(2-Nitroimidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide, and suberic acid which is closely related to the immunity function. These results suggested that FLP1 may regulate the intestinal immune response by modulating the gut microbiota and fecal metabolites in immunosuppressed mice thereby activating the immune system.

Polysaccharide NAP-3 Synergistically Enhances the Efficiency of Metformin in Type 2 Diabetes via Bile Acid/GLP-1 Axis through Gut Microbiota Remodeling

The polysaccharides of edible mushrooms are excellent phytochemicals for adjuvant treatment of metabolic diseases, but the potential mechanisms of synergistic effects are unclear. In this work, we discovered that NAP-3 enhanced the efficiency of metformin in lipid and glucose metabolism in type 2 diabetic (T2D) mice in a gut microbiome-dependent way. NAP-3 remodeled the intestinal microbial, resulting in the decreased activity of bile salt hydrolases and upregulation of CYP27A1 and CYP7B1 functions in the alternative pathway of bile acid synthesis, which leads to accumulation of the conjugated bile acids in ileum, specifically TβMCA and TUDCA. The accumulated conjugated bile acids either blocked or stimulated the nuclear receptors Farnesoid-X-receptor and TGR5, inducing the release of GLP-1 and ultimately enhanced glucose metabolism in mice. Collectively, our research indicated that edible mushroom polysaccharide NAP-3 may serve as a promising adjunctive oral therapeutic agent for T2D.

The structural characterization and UV-protective properties of an exopolysaccharide from a Paenibacillus isolate

Introduction

Overexposure to ultraviolet (UV) light is known to cause damage to the skin, leading to sunburn and photo-aging. Chemical sunscreen products may give rise to health risks including phototoxicity, photosensitivity, and photosensitivity. Natural polysaccharides have attracted considerable interests due to diverse biological activities.

Methods

A novel polysaccharide isolated was purified and structurally characterized using chemical methods followed by HPLC, GLC-MS, as well as 1D and 2D NMR spectroscopy. The photoprotective effect of the EPS on UVB-induced damage was assessed in vitro using cultured keratinocytes and in vivo using C57BL/6 mouse models.

Results

The average molecular weight of the EPS was 5.48 × 106 Da, composed of glucose, mannose and galactose residues at a ratio of 2:2:1. The repeating units of the EPS were →3)-β-D-Glcp (1→3) [β-D-Galp (1→2)-α-D-Glcp (1→2)]-α-D-Manp (1→3)-α-D-Manp (1→. In cultured keratinocytes, the EPS reduced cytotoxicity and excessive ROS production induced by UVB irradiation. The EPS also exhibits an inhibitory effect on oxidative stress, inflammation, and collagen degradation found in the photodamage in mice. 1H NMR-based metabolomics analysis for skin suggested that the EPS partly reversed the shifts of metabolic profiles of the skin in UVB-exposed mice.

Conclusion

The EPS exhibits skin photoprotective effects through regulating oxidative stress both in vivo and in vitro. Our findings highlight that the EPS is a potential candidate in sunscreen formulations for an efficient solution to UVB radiation.

A glucomannan produced by Bacillus velezensis HY23 and its growth promoting effect on soybeans under salt stress

The Bacillus genus is widely distributed in nature, has bacteriostatic and growth-promoting activities, and has broad application potential in agriculture. An exopolysaccharide (EPS) was extracted and purified from Bacillus velezensis HY23. Structural characterisation of the EPS was performed by chemical and spectroscopic analyses. Methylation analysis showed that the EPS of HY23 was composed of mannose and glucose at a ratio of 82:18 and was identified as glucomannan. Combined with the nuclear magnetic resonance (NMR) analysis, EPS from HY23 had a backbone of →2)-α-D-Manp-(1 → and →2,6)-α-D-Manp-(1 → branched at C-6 with terminal α-(3-O-Me)-D-Manp-(1 → and →6)-α-D-Manp-(1 → residues as the side chain. A certain amount of β-D-Glcp residues were also present in backbone. Moreover, EPS significantly improved the nitrogen-fixing activity and salt resistance of soybean seedlings by regulating the antioxidant pool and expression of ion transporters. These findings indicate that EPS from B. velezensis HY23 is a potential biostimulant for enhancing plant resistance to salt stress.

Glucan polysaccharides isolated from Lactarius hatsudake Tanaka mushroom: Structural characterization and in vitro bioactivities

Commercially available mushroom polysaccharides have found widespread use as adjuvant tumor treatments. However, the bioactivity of polysaccharides in Lactarius hatsudake Tanaka (L. hatsudake), a mushroom with both edible and medicinal uses, remains relatively unexplored. To address this gap, five L. hatsudake polysaccharides with varying molecular weights were isolated, named LHP-1 (898 kDa), LHP-2 (677 kDa), LHP-3 (385 kDa), LHP-4 (20 kDa), and LHP-5 (4.9 kDa). Gas chromatography-mass spectrometry, nuclear magnetic resonance, and atomic force microscopy, etc., were employed to determine their structural characteristics. The results confirmed that spherical aggregates with amorphous flexible fiber chains dominated the conformation of the LHP. LHP-1 and LHP-2 were identified as glucans with α-(1,4)-Glcp as the main chain; LHP-3 and LHP-4 were classified as galactans with varying molecular weights but with α-(1,6)-Galp as the main chain; LHP-5 was a glucan with β-(1,3)-Glcp as the main chain and β-(1,6)-Glcp connecting to the side chains. Significant differences were observed in inhibiting tumor cell cytotoxicity and the antioxidant activity of the LHPs, with LHP-5 and LHP-4 identified as the principal bioactive components. These findings provide a theoretical foundation for the valuable use of L. hatsudake and emphasize the potential application of LHPs in therapeutic tumor treatments.

Structural characterization of extracellular polysaccharides from Phellinus igniarius SH-1 and their therapeutic effects on DSS induced colitis in mice

Phellinus igniarius is a valuable medicinal and edible mushroom, and its polysaccharides exhibit excellent anti-inflammatory activity. During liquid fermentation to produce P. igniarius mycelia, the fermentation liquid is often discarded, but it contains extracellular polysaccharides. To better utilize these resources, P. igniarius SH-1 was fermented in a 100 L fermenter, and PIPS-2 was isolated and purified from the fermentation broth. The structural characteristics and anti-inflammatory activity of PIPS-2 were determined. PIPS-2 had a molecular weight of 22.855 kDa and was composed of galactose and mannose in a molar ratio of 0.38:0.62. Structural analysis revealed that the main chain of PIPS-2 involved →2)-α-D-Manp-(1 → 3)-β-D-Galf-(1→, and the side chains involved α-D-Manp-(1 → 6)-α-D-Manp-(1→, α-D-Manp-(1 → 3)-α-D-Manp-(1→, and α-D-Manp-(1. PIPS-2 alleviated the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice, improved the imbalance of inflammatory factors and antioxidant enzymes, and increased short-chain fatty acid contents. Combining the intestinal flora and metabolite results, PIPS-2 was found to regulate the abundance of Firmicutes, Lachnospiraceae_NK4A136_group, Proteobacteria, Bacteroides, and many serum metabolites including hexadecenal, copalic acid, 8-hydroxyeicosatetraenoic acid, artepillin C, and uric acid, thereby ameliorating metabolite related disorders in mice with colitis. In summary, PIPS-2 may improve colitis in mice by regulating the gut microbiota and metabolites.

CTCOSY-JRES: A high-resolution three-dimensional NMR method for unveiling J-couplings

Two-dimensional (2D) J-resolved spectroscopy provides valuable information on J-coupling constants for molecular structure analysis by resolving one-dimensional (1D) spectra. However, it is challenging to decipher the J-coupling connectivity in 2D J-resolved spectra because the J-coupling connectivity cannot be directly provided. In addition, 2D homonuclear correlation spectroscopy (COSY) can directly elucidate molecular structures by tracking the J-coupling connectivity between protons. However, this method is limited by the problem of spectral peak crowding and is only suitable for simple sample systems. To fully understand the intuitive coupling relationship and coupling constant information, we propose a three-dimensional (3D) COSY method called CTCOSY-JRES (Constant-Time COrrelation SpectroscopY and J-REsolved Spectroscopy) in this paper. By combining the J-resolved spectrum with the constant-time COSY technique, a doubly decoupled COSY spectrum can be provided while preserving the J-coupling constant along an additional dimension, ensuring high-resolution analysis of J-coupling connectivity and J-coupling information. Moreover, compression sensing and fold-over correction techniques are introduced to accelerate experimental acquisition. The CTCOSY-JRES method has been successfully validated in a variety of sample systems, including industrial, agricultural, and biopharmaceutical samples, revealing complex coupling interactions and providing deeper insights into the resolution of molecular structures.

The function and application of edible fungal polysaccharides

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

Extraction, purification, structural characteristics and biological properties of the polysaccharides from Armillaria mellea (Vahl) P. Kumm.: A review

Armillaria mellea (Vahl) P. Kumm. is a well-known homoeopathic plant with medicinal and culinary uses. Modern phytochemical researchers have successfully extracted and purified over 40 types of A. mellea polysaccharides (AMPs) from the fruiting bodies, hyphae and fermentation broth of A. mellea, and some of them have been analyzed and identified by their chemical structures. The impressive biological activity of these polysaccharides has been recognized by scientists worldwide. Many studies show that AMPs have remarkable antioxidant, anti-diabetic, anti-tumor, anti-inflammatory, immunoregulatory, hypolipidemic, thrombectomy, anti-aging, pulmonary protective, hepatic protective, anti-Alzheimer's properties, etc. However, the current understanding of the relationships between their chemical structure and biological activity, toxicological effects and pharmacokinetics remains limited. This article provides a systematic review of the research conducted over the past decades on the extraction and purification methods, structural characteristics, biological activity and mechanism of action of AMPs. The aim is to provide a research base that will benefit the future application of AMPs as therapeutic drugs and functional foods, and also provide insights for the further development of AMPs.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

Polysaccharides are promising biomolecules with lowtoxicity and diverse bioactivities in food processing and clinical drug development. However, an essential prerequisite for their applications is the fine structure characterization. Due to the complexity of polysaccharide structure, partial degradation is a powerful tool for fine structure analysis, which can effectively provide valid information on the structure of backbone and branching glycosidic fragments of complex polysaccharides. This review aims to conclude current methods of partial degradation employed for polysaccharide structural characterization, discuss the molecular mechanisms, and describe the molecular structure and solution properties of degraded polysaccharides. In addition, the effects of polysaccharide degradation on the conformational relationships between the molecular structure and bioactivities, such as antioxidant, antitumor, and immunomodulatory activities, are also discussed. Finally, we summarize the prospects and current challenges for the partial degradation of polysaccharides. This review will be of great value for the scientific elucidation of polysaccharide fine structures and potential applications.