Carbohydrate Research最新文献

Ethnopharmacological relevance: Tremella fuciformis is an edible fungus with a cultivation and consumption history of over a thousand years in China. In traditional Chinese medicine, it has the effects of moistening the lungs, soothing the intestines, nourishing the skin, and prolonging life, and is often used as a tonic food or added to soups. Its core bioactive component is Tremella fuciformis polysaccharides, which are widely concerned for their potential in health maintenance and disease adjuvant treatment.

Aim of the review: This review systematically summarizes the latest research progress in the extraction, structural characteristics, pharmacological activities, structure-activity relationships, quality control, and applications of TFPS. It deeply analyzes the controversies and limitations of existing studies, clarifies the correlation between structure and function, and provides a theoretical basis for the standardized production and high-value application of TFPS.

Materials and methods: Databases like ScienceDirect, PubMed, CNKI, and field journals were searched for extraction, structural characterization, pharmacology, and applications of Tremella fuciformis polysaccharides, including recent English/Chinese literature.

Results: Tremella fuciformis polysaccharides have diverse extraction methods (hot water, ultrasonic/microwave-assisted, etc.), with composite tech boosting yield over 50%. Structurally, they have α-1,3-D-mannan backbone, varied monosaccharides, and conformations (random coil, triple-helical). Pharmacologically, they modulate immunity, reduce inflammation/tumors, resist oxidation/aging, protect nerves, regulate metabolism, and maintain intestinal homeostasis. Quality control uses HPLC/GC-MS fingerprints and HPSEC-MALLS for quantification. Applications span pharma (immunoadjuvants), food (additives), cosmetics (moisturizers), and new materials (drug carriers).

Conclusion: Tremella fuciformis polysaccharides have great prospects but lack clarity on some mechanisms, higher-order structure research, and standardized quality criteria. With deeper study, they may bring new breakthroughs in industries of health maintenance, disease treatment, and cosmetics and skincare.

Solution-state two-dimensional (2D) ¹H-¹³C HSQC NMR is a powerful tool for polysaccharide structure elucidation but often suffers from limited sensitivity and broad peaks due to the low natural abundance of ¹³C and poor digital resolution of the indirect dimension, respectively, as well as the typically low concentration and high viscosity of polysaccharide solutions. It is therefore pivotal to improve the resolution of 2D ¹H-¹³C HSQC spectra for accurate peak picking and assignment, particularly in the indirect ¹³C dimension. In this study, we developed an algorithm that combines first derivative processing with a novel logarithmic cosine transformation (FDP-LCT) to convert 2D ¹H-¹³C HSQC spectra into local-resolution-enhanced images resembling a dark forest of straight, densely standing trees. These images revealed sharpened spectral features and enabled extraction of precise ¹H and ¹³C chemical shifts, as demonstrated using per-O-ethylated kappa- and iota-carrageenans, two sulfated galactans differing only by a single substitution at the O-2 position of anhydrogalactose. In conclusion, this approach provides an effective post-acquisition strategy for enhancing digital resolution in 2D HSQC spectra and improving the structural analysis of closely related complex polysaccharides.

Tetrasaccharide 1 from Bacillus anthracis represents an important target for the development of carbohydrates-based vaccines and diagnostic tools against the notorious disease anthrax. Here, we report the efficient chemical synthesis of tetrasaccharide 1 through [1 + 1+1 + 1] orthogonal one-pot glycosylation strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates, which avoids the potential issues inherent to one-pot glycan assembly with thioglycosides.

Enzymes are highly selective biocatalysts widely used in industrial processes due to their efficiency and specificity. Among them, cellulases play a crucial role in the degradation of cellulose, with significant applications across industries such as bioethanol production, textiles, and food processing. However, cellulase activity and stability are often compromised by reaction conditions, limiting their industrial scalability. Traditional aqueous and organic solvents pose challenges related to substrate solubility, toxicity, and environmental safety. Recently, green deep eutectic solvents (DESs) have emerged as promising alternatives that enhance enzyme performance while being cost-effective, biodegradable, and environmentally friendly. This review examines the effects of DESs on cellulase activity and stability, emphasizing their potential as co-solvents to address existing limitations. Polyol-based DESs are shown to enhance and stabilize cellulase activity. However, the concentration of DESs must be carefully optimized to achieve optimal enzyme performance.

Marine microorganisms produce extracellular polysaccharides with unique features, such as the presence of unusual monosaccharides, adhesiveness to biotic and abiotic surfaces, and close similarity to glycosaminoglycans (GAG), that are of considerable interest for biotechnological applications. In the present study, an extracellular microbial polysaccharide (EPS) has been isolated and structurally characterized. The EPS producer is the Gram-negative bacterium Alteromonas macleodii Mo169, previously isolated from a marine environment in French Polynesia. The bacterium has been cultivated using glycerol as the sole carbon source. Interestingly, the secreted EPS was composed of 2-acetamido-2-deoxy-guluronic acid (GulNA) and 2-acetamido-2-deoxy-glucose (GlcN), two amino sugars not commonly found in the Alteromonas genus. The purified EPS, with a molecular weight of 0.30 ± 0.01 MDa, consisted of the following repeating unit: →4)-α-L-GulNAc3OAcA-(1 → 3)-β-D-GlcNAc-(1 → .

Seven new resin glycosides, designated ipoalbins XXII (1)-XXVIII (7), together with one known resin glycoside (8), were isolated from the seeds of Ipomoea alba L. (Convolvulaceae). Structural elucidation was accomplished primarily through comprehensive NMR and MS analyses. All newly identified compounds possessed intramolecular cyclic ester (jalapin-type) architectures, in which the sugar moieties were partially acylated by organic acids, including acetic acid, (E)-2-methylbut-2-enoic acid, and 2S-methyl-3S-hydroxybutyric acid. Notably, two of the new compounds exhibited rare jalapin-type frameworks, characterized by esterification between the carboxyl group of the aglycone moiety and the hydroxyl group of an organic acid substituent located on the sugar chain. Furthermore, the cytotoxic activities of 1-8 against HL-60 human promyelocytic leukemia cells, as well as the antiviral activities of 1-8 and previously reported ipoalbins XI-XXI against herpes simplex virus type 1 (HSV-1), were assessed. All compounds demonstrated moderate cytotoxicity, whereas all showed notable antiviral activity against HSV-1.

Free radical depolymerization has been widely employed for polysaccharide structural and functional studies. However, H₂O₂-induced depolymerization of the unique sea cucumber derived fucosylated chondroitin sulfate (FCS) generated diverse fragments with oxidation at their reducing ends, thus limiting preparation of well-defined oligosaccharides. Here, a thermal dissociation initiator, potassium persulfate (KPS), was utilized to induce radical depolymerization of FCS, leading to depolymerized products that maintained their basic structural units and sulfate substituents. Structural analysis of the resulting oligosaccharides revealed that the reducing ends were uniformly GalNAc_4S6S acid, distinct from those generated by H₂O₂-induced FCS depolymerization. The major components, tetrasaccharide (FIIIa), heptasaccharide (FVa) and decasaccharide (FVIa) possessed GalNAc_4S6S residues at their non-reducing ends, demonstrating that the D-GlcA-β1,3-D-GalNAc_4S6S linkage was preferentially cleaved. A free radical depolymerization mechanism of FCS by KPS was proposed. The regular aldonic acid terminal formation was attributed to the strong oxidative capacity of the sulfate radical for extensive oxidation of the newly formed GlcA residue after β1,3 glycosidic linkage cleavage, and further oxidation of C-1 of GalNAc. KPS was thermally dissociated to generate sulfate radicals, which subsequently attacked FCS chains and led to their fragmentation. Moreover, biological activity assay showed that heptasaccharide FVa and decasaccharide FVIa demonstrated strong anticoagulant activity, primarily via iXase inhibition mediated by high-affinity interaction with FIXa. Intriguingly, the unique oxidized reducing end exhibited enhanced iXase inhibitory activity. Hence, our findings expanded the free radical depolymerization of FCS and enriched structure-activity relationship information for iXase inhibition.

Structure of the Acinetobacter baumannii strain MAR22-475 classified to KL223 type capsular polysaccharide (CPS) was established by component analyses, Smith degradation as well as ¹H and ¹³C NMR spectroscopy, including two-dimensional homonuclear ¹Н,¹Н COSY, TOCSY, ROESY and heteronuclear ¹Н,¹³C HSQC and HMBC experiments. The K223 CPS is composed of branched tetrasaccharide K-units containing two d-Glсp residues, and one residue each of d-GlcpNAc and d-Galp. The following structure of the tetrasaccharide repeating unit of the CPS was established.