The lipopolysaccharide (LPS) was obtained from a bacterium Pseudoalteromonas agarivorans KMM 232 (O-form) isolated from a seawater sample collected at a depth of 500 m. The O-polysaccharide (OPS) was isolated by mild acid degradation of the LPS and studied by chemical methods along with 1D and 2D H and C NMR spectroscopy, including H,H COSY, H,H TOCSY, H,H ROESY and H,C HSQC, and H,C HMBC experiments. The following new structure of the OPS from P. agarivorans KMM 232 (O-form) containing 2-acetamido-2-deoxy-d-glucose (D-GlcNAc), d-glucose (D-Glc), d-glucuronic acid (D-GlcA), 4,6-O-[(R)-1-carboxyethylidene]-d-galactose [D-Galp4,6 (R-Pyr)] and two residues of d-galactose (D-Gal) was established.

Bile acids have been known to play significant roles at certain physiological levels in gastrointestinal metabolism. Yet, they are known to be carcinogenic and aid in tumor progression in most cases, although the roles remain uncertain. Hence, we tested the cytotoxic potential of cholic acid (CA) loaded chitosan nanoparticles (CNPs) on Hep3B cells. The physicochemical properties of the CNPs synthesized with CA load (CA-CNPs) were determined using standard techniques such as ultraviolet-visible spectrophotometry (UV-Vis), fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The characteristic peak for chitosan nanoparticles were observed for plain CNPs (pCNPs) and CA-CNPs at around 300 nm as per UV-Vis analysis. FTIR analysis indicated the possible trapping of CA onto CNPs as certain peaks were retained and some peaks were shifted. XRD analysis determined that the peaks representing CA and pCNPs were collectively obtained in CA-CNPs. As per DLS analysis, the particle size, PDI and ζ-potential of the CA-CNPs were 259 nm, 0.284 and 30.4 mV. Further, the CA-CNPs were non-cytotoxic on Hep3B cells at the maximum tested concentration of 500 μg/mL. The viability at 500 μg/mL of CA-CNPs was two-fold higher than 500 μg/mL of pCNPs. Also, the pCNPs were not hemolytic and therefore could not have played a role in the increase of viability after treatment with CA-CNPs, which indicates that CA posed a major role in increased viability of Hep3B cells. As per quantitative PCR (qPCR), the upregulated gene expressions of PI3K, Akt, mTORC2, cMyc, Fibronectin, hVPS34, Slug and ZEB1 and the downregulated expression of the tumor suppressor PTEN indicates that PI3K/Akt/mTOR pathway mediated the induction of epithelial-to-mesenchymal transition (EMT) in response to CA-CNPs treatment on Hep3B cells.

In this study, the mechanism and nature of mechanical force-induced conformational transitions of alginate oligomers with different ratios of β-d-mannuronic acid (M unit) and α-l-guluronic acid (G unit) units were investigated. The influence of the type of glycosidic linkage in either homo- or heterooligomers on the nature of conformational transitions was also considered. For this purpose, two different theoretical methods were used: quantum mechanics (QM) at the DFT level with the EGO (Enforced Geometry Optimization) approach previously tested also for other saccharide systems, and molecular dynamics (MD) simulations within hybrid interaction potentials, which take into account both the ab initio (QM) level of theory and classical molecular mechanics (MM) force fields. This allowed to characterize in detail the structural and energetic properties of the conformational transition occurring upon the influence of external, mechanical forces (e.g. ring conformations at the path of ring-inversion process as well as the energies corresponding to initial, final and intermediate states). The results indicate qualitatively various responses against the applied force, depending on the G:M ratio, which have their source in differing topologies of glycosidic linkage in either G or M units. This is of potential relevance for determining the content of naturally heterogeneous alginate chains by the AFM experimental studies. The effects of explicit solvent and non-zero temperature are not of primarily importance in the context of determined stretching properties.

The "shell biorefinery," which valorizes the shell waste chitin into fine chemicals, has developed rapidly in recent years. Herein, we present a novel base-free heteropolyacid-catalyzed oxidation method for the transformation of chitin biomass into organic acid. After a series of optimization experiments, a 5.93 % yield of formic acid and 25.09 % yield of acetic acid were achieved in the presence of 0.5 equivalent of Mo-V-P heteropolyacids (HPMoVO·2HO) and air at 180 °C under hydrothermal conditions for 4 h. Meanwhile, we have demonstrated that the Keggin-type heteropolyacid catalysts are capable of efficiently converting microcrystalline chitin into organic acids. The synthesized heteropolyacids are well characterized with FT-IR, XRD, ICP-AES, and TGA. The possible reaction pathway was speculated accordingly. This method offers several advantages, including readily available raw materials, simple operation, and relatively higher yield.

This study presents a novel synthesis method of N,N,N-trimethyl chitosan (TMC) by using a non-nucleophilic base and optimizing the solvent system for enhanced scalability, while addressing critical factors such as viscosity management and stirring efficiency. The study objectives also included achieving high N,N,N-trimethylation without O-methylation while minimizing reagent use. Eight bases, three solvent systems, and varying levels of dilution were explored to mitigate viscosity challenges and gas evolution. H NMR spectroscopy was used to characterize the TMC products. The integral values of the peaks at 3.3, 3.0, and 2.8 ppm, corresponding to trimethyl, dimethyl, and monomethyl groups, were used to quantify the methylation degrees. The most promising initial results were obtained with N,N-diisopropylethylamine (DIPEA) base, and DMF as solvent. Using 6 eq methyl iodide (MeI) relative to chitosan and DIPEA as base, up to 68 % DTM was achieved. Applying Design of Experiments (DoE), the method was further optimized under diluted conditions, crucial for industrial scalability and viscosity control. Results from a full factorial design (3) revealed that diluted medium effectively prevented viscosity concerns, achieving a notably low viscosity of 5.9 cP in the reaction mixture, a 16-fold decrease in viscosity, compared to initial experiments. It was also established that both the MeI reagent and the base addition are significant factors for the DTM response, with both factors showing quadratic effects. The DoE model demonstrated high significance (R = 0.97), high precision for future prediction (Q2 = 0.87), good model validity (0.84) and excellent reproducibility (0.96). The results mark a notable advancement in TMC synthesis, offering an efficient and practical method with significant implications for industrial applications.

Seaweeds are natural sources of sulfated polysaccharides (SPs), biopolymers with remarkable pharmacological properties, including biological actions capable of attenuating components of the inflammatory process such as edema, cytokines, cell migration and pain. Our results confirm that SPs obtained from Gracilaria domingensis (SP-GD) are agarans, primarily composed of residues of β-d-galactopyranose 6-sulfate and 3,6-anhydro-α-l-galactopyranose. Specifically, SP-GD at a dose of 10 mg/kg was effective in significantly reducing paw edema induced by carrageenan or histamine, serotonin, bradykinin, 48/80 and prostaglandin E2. SP-GD (10 mg/kg) was also able to reduce neutrophil migration and the activity of the myeloperoxidase enzyme in carrageenan-induced peritonitis, as well as conserve glutathione concentration and reduce malondialdehyde levels in the animals' peritoneal fluid. Furthermore, it showed antinociceptive action in the abdominal writhing test induced by acetic acid and in the paw licking test induced by formalin. Thus, the results obtained allow us to infer that SPs extracted from G. domingensis at a dose of 10 mg/kg have anti-inflammatory effects by reducing neutrophil migration and modulating the activity of vasoactive mediators and antinociceptive effects by acting, at least in part, through a peripheral mechanism dependent on the negative modulation of inflammatory mediators.

Chitosan derivatives, including O-carboxymethyl chitosan (CMC), N-(2-hydroxypropyltrimonium chloride)-O-carboxymethyl chitosan (QCMC), and N-(2-hydroxypropyltrimonium chloride)-O-dodecylylpyridine chitosan quaternary ammonium salt (DQCMC), were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy, H nuclear magnetic resonance (H NMR) spectroscopy, Ultraviolet-visible (UV-vis) spectroscopy, and element analysis (EA). The antibacterial activities of chitosan and chitosan derivatives against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated through the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibacterial rate assays. Results demonstrated that DQCMC exhibited significantly higher antibacterial efficacy compared to chitosan, CMC, and QCMC. The MIC of DQCMC against E. coli and S. aureus were 31 μg/mL and 7 μg/mL, respectively, with a 100 % antibacterial rate at a concentration of 0.5 mg/mL. Furthermore, assessment of mouse fibroblast (L929) cell viability using cell counting kit-8 (CCK-8) methods revealed no toxicity associated with the material.

The increasing concern over sugar-related health issues has sparked research interest in seeking alternatives to sucrose. Trehalulose, a beneficial structural isomer of sucrose, is a non-cariogenic sugar with a low glycemic and insulinemic index. Besides its potential as a sugar substitute, trehalulose exhibits high antioxidant properties, making it attractive for various industrial applications. Despite its numerous advantages and potential application in various sectors, the industrial adoption of trehalulose has yet to be established due to lack of studies on its characteristics and practical uses. This review aims to provide a comprehensive overview of the properties of trehalulose, emphasizing its health benefits. The industrial prospects of trehalulose as sweetener and reducing agent, particularly in food and beverages pharmaceutical, and cosmeceutical sectors, are explored. Additionally, the review delves into the sources of trehalulose and the diverse organisms capable of producing trehalulose. The biosynthesis of this sugar primarily involves an enzyme-mediated process. Thus, these enzymes' properties, mechanisms, and the heterologous expression of genes associated with trehalulose production are explored. The strategies discussed in this review can be improved and applied to establish trehalulose bio-factories for efficient synthesis of trehalulose in the future. With further research and development, trehalulose holds promise as a valuable component across various industries.

Synthetic and natural polymers are widely used for constructing drug delivery systems. Biocompatibility, water solubility and non-toxicity make polymers a convenient matrix for encapsulation, delivery and release of bioactive compounds. Coupling of a drug with a biodegraded polymer matrix is a promising way for a controlled drug delivery. Along this line, the degradation of the four polymers in the presence of two enzymes in aqueous solutions was investigated. The following polymers were used: natural polysaccharides, sodium alginate and sodium hyaluronate, artificial (modified) sodium carboxymethylcellulose and synthetic sodium polyacrylate (control); their degradation was caused by the addition of alginate lyase and hyaluronidase. The first enzyme only cleaved the specific alginate substrate and left three other intact. Contrastingly, the second enzyme degraded all three polysaccharides, including artificial carboxymethylcellulose, but did not degrade synthetic polyacrylate. The biodegradation of polymers was accompanied by decreasing the size of polymer particles in solution from 100 to 200 nm down to 20-30 nm; the latter are capable of removing from the body through the kidneys. The initial polysaccharides showed the negative surface charge in aqueous solution, which changed but retained negative after biodegradation. The initial and biodegraded polysaccharides demonstrated negligible cytotoxicity during long exposure period. The obtained results are valuable for the development of polymer carriers for drug encapsulation and delivery.

Photoredox catalysis has recently emerged as a powerful approach for preparing oligosaccharides because it uses mild conditions, is compatible with partially or completely unprotected carbohydrate substrates, and exhibits impressive regio- and stereo-selectivity and high functional group tolerance. However, most catalytic photoredox reactions require an external photocatalyst (organic dye or expensive transition-metal complex) to deliver key glycosyl radicals. Several photocatalyst-free photocatalytic reactions that avoid the use of expensive metal salts or organic-dye additives have received significant attention. In this review, we highlight the most recent developments in photocatalyst-free light-promoted carbohydrate synthesis and modification, which is expected to inspire broad interest in further innovations in the green synthesis of saccharides.

In this study, we prepared granulated chitosan (G-CS)/catechin tablets with excellent disintegration properties. We then compared their physical properties, dissolution behavior, and pharmacokinetic profile to non-granulated chitosan (N-CS)/catechin tablets. During the tableting process, the G-CS/catechin tablets demonstrated significantly higher compatibility and superior manufacturability, as evidenced by lower ejection and detachment stress than the N-CS/catechin tablets. This resulted in more robust tablets with better physical properties. The dissolution of catechin from the G-CS/catechin tablets occurred significantly faster than from the N-CS/catechin tablets, resulting in a significantly higher 2,2'-azino-bis(3 ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity. Similarly, the primary catechin components of the tablets, epigallocatechin gallate (EGCG) and caffeine, showed faster dissolution and membrane uptake from the G-CS/catechin tablets. These indicate a more efficient tablet formulation than N-CS/catechin tablets. Furthermore, the absorption and bioavailability of EGCG and caffeine in rats were significantly higher after oral administration of the G-CS/catechin tablets than the N-CS/catechin tablets. These findings suggest that G-CS/catechin tablets, having better disintegration properties than N-CS/catechin tablets, could allow for combination with other supplements, leading to the design of highly efficient supplement combination tablets.

The mucus layer on epithelial cells is an essential barrier, as well as a nutrient-rich niche for bacteria, forming a dynamic, functional and symbiotic ecosystem and first line of defense against invading pathogens. Particularly bacteria in biofilms are very difficult to eradicate. The extensively O-glycosylated mucins are the main glycoproteins in mucus that interact with microbes. For example, mucins act as adhesion receptors and nutritional substrates for gut bacteria. Mucins also play important roles in immune responses, and they control the composition of the microbiome, primarily due to the abundance of complex O-glycans. In inflammation or infection, the structures of mucin O-glycans can change and thus affect mucin function, impact biofilm formation and the induction of virulence pathways in bacteria. In turn, bacteria can support host cell growth, mucin production and can stimulate changes in the host immune system and responses leading to healthy tissue function. The external polysaccharides of bacteria are critical for controlling adhesion and biofilm formation. It is therefore important to understand the relationships between the mucus layer and microbes, the mechanisms and regulation of the biosynthesis of mucins, of bacterial surface polysaccharides, and adhesins. This knowledge can provide biomarkers, vaccines and help to develop new approaches for improved therapies, including antibiotic treatments.

Capsular polysaccharides (CPS) of Acinetobacter baumannii is a virulence factor with diverse structures. CPS are produced by the CPS biosynthesis gene cluster in their K locus (KL). However, CPS variations may occur due to insertion of additional genes from external sources, e.g., prophages. Recently, the CPS structure from a clinical isolate, BAL062 which includes KL58 locus, was found to have a pseudaminic acid isomer (8ePse5NAc7NAc) as a result of prophage inserted epaA/epaB genes. Here, we report a CPS structure produced by A. baumannii strain MRSN31468 which also belongs to a KL58 type. The K58 CPS structure was determined by 1D and 2D NMR analysis of the oligosaccharides derived from the CPS by a phage depolymerase, and supported by the sugar composition analysis. The K58 CPS structure has the following tetra saccharide repeating unit. The K58 CPS differs from the CPS from BAL062 only by replacing 8-epimerized β-8ePse5NAc7NAc with β-Pse5NAc7NAc.

Curcumin (Cur) is a naturally hydrophobic polyphenol, and it has a wide range of physiological functions. But the practical application of Cur is constrained by its low water solubility and poor stability. To improve these deficiencies of Cur, a novel Cur derivative (CS-Cur) was prepared by grafting chitosan (CS) with Cur through a one-step reaction of a free radical-mediated redox system. A series of characterizations provided evidence that the grafting of CS with Cur was successful. The obtained CS-Cur showed lower crystallinity and thermal properties than CS and Cur. After grafting, the water solubility of CS-Cur was found to be 9.76 ± 2.45 g/L and greatly improved. Meanwhile, the CS-Cur showed good photothermal stability, antioxidant activity, and photodynamic antibacterial activity in an aqueous solution, and it had good in vitro biosafety. This provides an idea for the design and synthesis of novel highly water-soluble Cur derivatives and also improves the practical application of Cur in aqueous systems.

The diversity of polyhydroxylated indolizidine (PI) iminosugars is ever-expanding due to the wide range of methods developed and substrate choice during synthesis. This study used an HWE precursor derived from d-glucose to extend the chain length at the C1 position. A double reductive amination and dihydroxylation of the resulting olefin, followed by intramolecular cyclization, enabled the successful synthesis of a new PI. In addition, the precursor intermediate for Mitsunobu reaction was utilized in synthesis of a new iminononulol.

A straightforward synthesis of the pentasaccharide with a readily available linker arm corresponding to the O-antigenic polysaccharide of Acinetobacter junii strain 65 has been achieved in good yield. The synthesis has been carried out using thioglycosides as glycosyl donor in the presence of a combination of N-iodosuccinimide (NIS) and trifluoromethanesulfonic acid (TfOH) as thiophilic activator. The yields of the glycosylation steps were very good with satisfactory stereochemistry at the glycosidic linkages. The pentasaccharide derivative has also been obtained using a one-pot iterative glycosylation strategy.

Portulaca oleracea L., a plant with both edible and medicinal properties, is traditionally valued for its diuretic, antipyretic, antiseptic, antispasmodic, and anthelmintic functions in folk medicine. P. oleracea polysaccharide (POP), a pivotal bioactive component, has various biological activities. Notably, their immunomodulatory capabilities have emerged as a significant area of research. The extraction, purification, monosaccharide composition, structure characterization, and biological activity of POP have been extensively investigated to identify the active components and to clarify their pharmacological actions and underlying molecular mechanisms. It aims to delineate the pharmacological mechanisms and molecular pathways associated with these polysaccharides, thereby underscoring their therapeutic promise and nutritional significance. Furthermore, the review critically examines the current research landscape of POP, identifying gaps and proposing innovative perspectives to enrich the scientific discourse surrounding these bioactive compounds.

Biodegradability, biocompatibility, abundant supply from renewable sources, and affordability are the outstanding properties of cellulose that have prompted substantial studies into its potential in biomedical applications. Beyond terrestrial sources of cellulose, seaweeds have attracted much attention as a potential source of cellulose because they are widely available. Cellulose and its byproducts may be extracted from various macroalgae species, including red, green, and brown algae. The extracted cellulose's qualities vary depending on the algae species, age, and extraction process utilized. Cellulose's characteristics are enhanced through chemical modifications, specifically etherification and esterification, which substitute functional groups for hydroxyl groups, yielding a range of products, including cellulose acetate (CA), cellulose nitrate, cellulose sulfate, methylcellulose, and carboxymethyl cellulose (CMC). The ability to modify CMC characteristics for particular applications is explored through techniques including grafting processes mixing, and cross-linking with other polymers. Moreover, tissue engineering is given significant consideration in the growing use of CMC and its altered forms in biological applications. These alterations allow for the production of scaffolds that promote tissue regeneration and cell proliferation, enabling CMC-based scaffolds for various tissue engineering uses. This review provides a comprehensive overview of CMC's properties, modifications, and potential in tissue engineering.

A novel oligosaccharide (NTRP60-W-2) with an average molecular weight of 1377 Da was isolated and purified from Nicotiana tabacum roots. Its structural characteristics and immunomodulatory properties were investigated. Structural analysis revealed that NTRP60-W-2 was composed exclusively of glucose, featuring →1)-α-D-Glcp-(6→ backbone. Immunological assays demonstrated that NTRP60-W-2 significantly enhanced cell viability, nitric oxide production and cytokine secretion (IL-6 and TNF-α) in RAW264.7 cells. These findings provide a foundation for further exploration of Nicotiana tabacum carbohydrates and their potential biological activities.

A stereoselective synthesis of fused tricyclic framework of epi-parvistemonine A from D-glucono-δ-lactone is described. The synthetic strategic is based on the stereoselective construction of the 7-membered cyclic skeleton via a cross-metathesis reaction followed by a Michael type cyclization promoted by TfO.