Chitin, a linear β-1,4-linked polymer of N-acetyl-d-glucosamine (GlcNAc), is an abundant but recalcitrant polysaccharide. Enzymatic degradation offers a sustainable route to bioactive chitin oligosaccharides (NCOSs), yet faces challenges in yield, specificity, and process efficiency. This review systematically covers chitinase classification, catalytic mechanisms (GH18 retaining vs. GH19 inverting, and LPMO oxidative cleavage), and recent advances in enzyme engineering-including rational design, directed evolution, and synergistic multi-enzyme systems (chitinase + LPMO + GlcNAcase) that significantly enhance saccharification efficiency and modulate product profiles. We also discuss process optimization strategies and emerging computational tools for biocatalyst design as future perspectives. The convergence of these approaches provides a roadmap for the efficient bioconversion of chitin into value-added oligosaccharides for nutraceutical and food applications.

In this study, we converted prawn shell waste-derived chitosan into a hydrazone-functionalized Schiff base containing 2-hydroxy-1-naphthaldehyde moieties through sequential chemical modifications. We characterized the synthesized chitosan-based Schiff base using FTIR, UV-visible spectroscopy, [1]H NMR, [13]C NMR, HR-MS, and HPLC. The hydrazone Schiff-base formation was confirmed by characteristic CN stretching in the FTIR spectrum and azomethine (CHN) proton signals in the [1]H NMR spectrum, consistent with hydrazide condensation with 2-hydroxy-1-naphthaldehyde. The material exhibited colorimetric sensing, solid-state fluorescence, antimicrobial, antifungal, and antioxidant properties. Naked-eye color changes were observed in the presence of Fe[2+], Fe[3+], Pb[2+], OH[-], CN[-], and CO3[2-] ions, while fluorescence changes occurred with Al[3+] and Ag [+] ions. The detection limits for Al[3+], Ag[+], Fe[3+], Fe[2+], and Pb[2+] were 3, 5, 9, 10, and 12 ppm, respectively, while those for OH[-], CN[-], and CO3[2-] were 8, 4, and 3 ppm, respectively. The compound also exhibited strong yellow-green solid-state fluorescence under UV irradiation. Furthermore, the compound showed antibacterial activity against Escherichia coli and Staphylococcus aureus, antifungal activity against Candida albicans, and 76.11% DPPH radical-scavenging activity. Molecular docking studies using a representative oligomeric model of the material indicated predicted binding affinities of -6.8, -6.5, and -8.7 kcal/mol for C. albicans CYP51, E. coli DNA gyrase B, and S. aureus Sortase A, respectively. Overall, this work demonstrates an eco-friendly, sustainable approach to valorizing prawn shell waste into advanced, multifunctional bio-based materials with promising environmental, analytical, and biomedical applications.

Citrus reticulata Blanco peels are a common edible fruit peel, featuring rich nutritional properties and diverse physiological activities. It is rich in bioactive components such as polysaccharides, flavonoids, alkaloids, essential oils, and phenolic acids. Citrus reticulata Blanco peels polysaccharides (CrBpps) are among its major bioactive substances. CrBpps possess a variety of biological activities, including antioxidant, anti-liver steatosis, anti-obesity, and immune-enhancing effects. The extraction, purification, structural characterization and biological activity of CrBpps have been studied, but the research and discussion on more efficient extraction and purification methods, structural analysis methods, the relationship between structure and biological activity, toxicology are still relatively limited. This article reviews the extraction, purification, structural characterization, biological activities and other potential values of CrBpps, and elaborates the beneficial effects of CrBpps on health and its great potential in practical applications.

The stereoselective synthesis of C-3-thiopyrimidine-based glycohybrids remains largely under explored. An efficient and highly stereoselective one-pot organocatalytic strategy has been developed for the synthesis of new 2,3-dideoxy-C-3-thiopyrimidine-based C-3-thio-glycohybrids from Perlin's aldehydes and pyrimidine-2-thione derivatives under mild, metal-free conditions. l-proline used as an inexpensive organocatalyst, the reaction proceeds smoothly at room temperature to afford twenty new glycohybrids in good to very good yields with excellent equatorial selectivity at C-3. The structures and stereochemical configurations of the products were established by spectroscopic analyses and single-crystal X-ray diffraction studies. The operational simplicity, metal-free nature, and high stereoselectivity make this protocol an attractive and sustainable approach for accessing privileged C-3-thioglycohybrids.

Wild blackthorn (Prunus spinosa L.) fruits are rich in bioactive compounds. This study examines the water-soluble portion of the 5% KOH-extracted phenolic polysaccharide-protein material previously associated with high antioxidant activity. Ion-exchange chromatography of its water-soluble portion yielded seven subfractions with distinct monosaccharide profiles and chemical compositions. NMR analysis indicated that the water-soluble portion of the KOH complex contains a heterogeneous mixture of carbohydrate residues and structural motifs. The data were consistent with GalpA/Rhap-containing pectic domains, branched α-(1 → 5)-arabinan-type and β-(1 → 4)-galactan-type motifs, as well as xylan/glucuronoxylan-related structures, β-(1 → 4)-Glcp-containing components, and minor Manp-type residues. Subfractions 3F-5F are enriched in O-methylated monosaccharides, while 4F-6F exhibit higher Manp contents. These findings indicate substantial structural heterogeneity within the carbohydrate component of the phenolic polysaccharide-protein complex from blackthorn fruits.

Novel N-Arylacetamide-functionalized chitosan derivatives were synthesized and characterized by FT-IR spectroscopy, [1]H NMR and XRD analysis methods. The antibacterial was analyzed by the minimum inhibitory concentration (MIC) method of new derivatives obtained from modified chitosan against different Gram-positive and Gram-negative strains. In particular, the synthesized chitosan N-arylacetamide derivatives showed an identical high activity in all tests (62.5 μg/mL MIC vs. unmodified chitosan and commercial antibiotics). Molecular docking and MM-GB/SA calculations showed that the top scoring-compound, CS-PPHA had a docking score of -15.38 kcal/mol and ΔGbind (MM-GB/SA) of -117.02 kcal/mol. Results of molecular dynamics simulations provided additional indication that CS-PHA, CS-MPHA, CS-DMPHA and CS-NPHA maintain a rigid and stable binding mode with low backbone deviations (RMSD ≤ 1.59 Å). By contrast, the CS-OPHA and CS-PPHA derivatives all trigger pronounced global conformational rearrangements (RMSD ≥ 2.07 Å). These quaternary transitions at the macroscopic scale are not related to core unfolding events but rather can be attributed to a quite strong and spatially compact hyper-flexibility from within a gating loop (residues 190-205). In particular, in the presence of CS-OPHA, this loop displays a pronounced fluctuation peak at nearly 7.0 Å that allows room for the protein to take up the bound ligand. These results highlight the potential of N-arylacetamide-containing chitosan derivatives as effective antibacterial agents for biomedical and surface-coating applications.

Neuromorphic electronics integrate state storage with signal transformation; nevertheless, a device that exhibits resistive switching is not inherently a neuromorphic element, necessitating a thorough investigation into how specific material structures dictate these functions. In this context, cellulose, chitosan, pectin, and starch are chemically distinct polysaccharides characterized by functional groups (hydroxyl, amino, and carboxyl), chain organization, counterions, and water content that can influence ion transport and electrode reactions. This review examines evidence from glycan chemistry and hydration to ion transport, switching mechanisms, and measured memory or synaptic responses. We compare two-terminal cells with electrolyte-gated devices and distinguish direct experimental demonstrations from unproven mechanistic interpretations. We also identify cases where reported values are not comparable because of differences in polymer composition, electrodes, humidity, and pulse protocols. The resulting framework emphasizes carbohydrate chemistry while treating device metrics and environmental lifetime as linked design outcomes. Finally, this review outlines a prioritized set of experiments designed to determine if molecular descriptors can predict ionic relaxation and device behavior under matched fabrication and measurement conditions.

Asymmetric synthesis has reshaped modern organic synthesis by empowering conventional organic transformations to construct enantiomerically enriched molecular architecture. Amidst the various catalytic techniques, organocatalysis with the aid of carbohydrate derivatives presents itself as one of the most reliable and flourishing catalytic strategies. Owing to the unique structural and stereochemical features of carbohydrates, along with their adaptable skeleton, biocompatibility and renewable origin, these catalysts are becoming one of the most sustainable and dependable classes of catalysts. Their catalytic competence can be envisioned by the broad spectrum of chemical transformations in which they have induced high asymmetry for a vast array of substrates under mild conditions. This article focuses on exceptional traits of the carbohydrate moiety that result in their extraordinary catalytic ability, together with the vast array of reactions catalysed by carbohydrate-based catalysts with mechanistic insights. It also highlights the significance of carbo-catalysis in expanding green chemistry principles to sustainable and high-performance asymmetric synthesis, enriching the world of drug-discovery and pharmaceutical practices.

Carbohydrates are essential biomolecules in nature for their numerous biological functions. To advance in-depth understanding of complex biochemical processes, obtaining pure, structurally well-defined carbohydrates is crucial. Despite extensive progress, achieving high yields with precise anomeric stereocontrol through chemical glycosylation remains a long-standing challenge. In the last few years, redox-catalyzed C-S bond activation strategies have opened new opportunities in glycosylation chemistry by enabling catalytic activation of thio-glycosyl donors. In particular, photoredox, electrochemical, and radical-mediated approaches have emerged as versatile tools, offering efficient and highly stereoselective glycosylation pathways. These methods expand the scope of thio-donor activation and provide practical routes to challenging glycosidic linkages under mild conditions. This review summarizes recent progress in the stereoselective synthesis of C-, N-, and O-glycosides via anomeric C-S bond activation, showing significant potential for synthesizing biologically relevant glycoconjugates and carbohydrate-based scaffolds.

Yeast β-glucans (YBG) are associated with beneficial health effects; however, the mechanisms underlying their biological activity remain incompletely understood. To investigate whether these effects are mediated by microbial metabolites, this study evaluated the immunomodulatory capacity of short-chain fatty acids (SCFA) produced during YBG fermentation by human intestinal microbiota. Yeast cell wall β-glucans were purified by treatment with NaOH and acetic acid, and its structural characteristics were confirmed by Nuclear Magnetic Resonance (NMR) of 1H, 13C, and 1H-13C HSQC, alongside FTIR spectroscopy. Fermentability was assessed in vitro using pooled faeces from 4 healthy adults. Gas chromatography analysis of SCFA and branched chain fatty acids (BCFA) production after 24 and 48 h confirmed that β-glucans can be fermented by intestinal microbiota, producing mainly acetic, propionic and butyric acids. Next-generation sequencing revealed that YBG fermentation selectively enriched the relative abundance of Selenomonadaceae and Veillonellaceae families. To evaluate the biological relevance of the produced metabolites, solutions of acetic, propionic and butyric acids were formulated individually to mimic post-fermentation concentrations and applied separately to Caco-2/TC7 human enterocytes exposed to a pro-inflammatory stimulus. SCFA effectively modulated the inflammatory response, suggesting that the biological effects associated with YBG fermentation could be mediated, at least in part, by microbiota-derived SCFA. This study integrates, within a single in vitro experimental framework, the human colonic fermentation of YBG, SCFA and BCFA production, intestinal microbiota composition, and immunomodulatory effects. Additionally, these findings support the valorization of brewery by-products as potential functional ingredients in human nutrition.

Polysaccharides from Dimocarpus longan (DLP) have attracted increasing interest for their structural diversity and potential health benefits. This review summarizes DLP extraction and purification methods, structural characteristics, biological activities, and chemical modification strategies, with an emphasis on their potential applications in the food industry. Preclinical studies suggest that DLP possess immunomodulatory, antitumor, and anti-inflammatory activities and can modulate the gut microbiota. However, their structure-activity relationships remain insufficiently understood, limiting the rational development of DLP-based food ingredients. Future research should clarify their fine structures and higher-order conformations, establish quantitative structure-activity relationships, and elucidate the mechanisms underlying their biological activities. Further evaluation of safety and efficacy is also needed to support translation into food applications. This review provides a basis for future research and the development of DLP as functional food ingredients.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains one of the leading causes of death from a single infectious agent worldwide. The emergence of multidrug-resistant (MDR) and extensively drug resistant (XDR) strains has further compounded the need for effective intervention strategies and rapid diagnostic approaches. One of the striking features of Mtb is its remarkably thick and waxy cell wall characterized by the presence of arabinogalactan (AG), lipoarabinomannan (LAM), peptidoglycan and mycolic acids. Further, arabinose and galactose residues in AG and LAM occur in the furanose form whereas the mannose occurs in the pyranose form. The terminal mannose-cap region of Mtb LAM contains the unusual 5-deoxy-5-methylthio-D-Xylf (MTX) residue, a rare sugar that shields mannose caps from recognition by host immune receptors. The presence of MTX moiety in the terminal portion poses a significant synthetic challenge while assembling the LAM fragments. In this endeavour, we have developed a convergent strategy for the synthesis of the terminal octasaccharide moiety using silver-assisted gold-catalyzed glycosylations. A key feature of this approach is the late-stage installation of the methylthio functionality enabling the synthetic flexibility and versatility.

Alzheimer's disease (AD) is the most common neurodegenerative disorder and the primary cause of dementia. Although natural polysaccharides exhibit significant therapeutic potential against AD due to their multi-target activities, the structure-activity relationship (SAR) of uronic acid oligosaccharides-particularly the influence of specific glycosidic linkages and monosaccharide compositions-remains insufficiently characterized. To address this, we utilized a highly selective TEMPO oxidation system to prepare four structurally distinct uronic acid oligosaccharides (α1,4-G, β1,4-G, β1,3-G, and β1,4-M/G) from diverse natural polysaccharides. NMR spectroscopy showed that the resulting oligosaccharides retained the major glycosidic linkage characteristics of their parent polysaccharides, while oxidation and depolymerization also occurred during the reaction. Comprehensive in vitro and in vivo evaluations demonstrated that the β-1,4-glycosidic linkage is a critical structural determinant for neuroprotective activity against Aβ-induced neuronal damage and cognitive impairment, while β1,4-M/G and β1,4-G showed different effects under the present experimental conditions. Mechanistic studies revealed that both β1,4-G and β1,4-M/G ameliorated Aβ-induced cognitive impairment and were associated with alterations in the gut microbiota and related metabolites. Importantly, fermentation products generated from these oligosaccharides by the AD microbiota were associated with enhanced Treg differentiation, which may potentially contribute to the observed neuroprotective effects. These findings provide systematic insights into the SAR of uronic acid oligosaccharides and support the further investigation of β-1,4-linked uronic acid oligosaccharides as potential neuroprotective candidates.

Polysaccharides from edible and medicinal fungi have been widely investigated, but the relationships among fungal ecological context, polysaccharide characteristics, and structure-activity associations (SARs) remain insufficiently resolved. This review examines bamboo-associated edible and medicinal fungi (BEMF), defined as fungi associated with bamboo, bamboo-derived substrates, or bamboo-forest habitats. We summarize reported polysaccharide characteristics, including molecular weight, monosaccharide composition, chemical modifications, glycosidic linkages, branching, conformation, and biological activities. Comparisons are interpreted cautiously because studies often differ in fungal species or strain, substrate, cultivation conditions, extraction and purification procedures, structural analyses, and bioactivity assays. Accordingly, observed differences are considered primarily hypothesis-generating rather than evidence of a bamboo-specific ecological effect. Reported antioxidant, immunomodulatory, antitumor, gut microbiota-modulating, and metabolic activities are evaluated using a three-level framework distinguishing correlative observations, SAR associations, and evidence approaching causal mechanisms. The proposed "niche → structure → activity" relationship is presented as a testable hypothesis. Standardized isogenic-strain comparisons using bamboo-derived and non-bamboo substrates are proposed for future validation. Artificial intelligence applications and key methodological gaps are also discussed.

Levan, a fructose homopolymer produced by many bacterial genera, particularly Bacillus, offers exceptional physicochemical properties and broad industrial potential. Lichens represent remarkable yet underexplored microhabitats which harbor many bacterial genera. Therefore, lichens may offer a unique opportunity to discover efficient biopolymer producing strains and bioactive compounds. Lichen-associated bacteria TLs4 and TLs25, isolated from Platismatia sp. and Pseudevernia sp., respectively, were cultivated in sucrose-rich medium and their exopolysaccharides were analyzed. Both strains produced exopolysaccharide yields (46.48 ± 3.46 and 43.44 ± 1.72 g/L) under in vitro conditions. NMR spectroscopy confirmed the exopolysaccharide is homogeneous β-(2/6)-linked levan, and GPC-MALLS analysis revealed a bimodal molecular weight distribution. Whole-genome sequence analysis revealed single circular chromosomes of 4.34 Mb (TLs4) and 4.27 Mb (TLs25), with >99% average nucleotide identity to Bacillus licheniformis. CAZyme profiling revealed rich carbohydrate-active enzyme repertoires in both genomes. GH68 levansucrases of both isolates are strictly conserved and identical to DSM13, indicating they are not unique to lichen-associated strains. Comparative genomic analysis revealed strain-specific features in prophage-associated regions, sugar nucleotide metabolism, ABC transporters, and biosynthetic gene clusters. AntiSMASH analysis revealed a beta-lactone-associated gene cluster potentially associated with a distinct fatty-acid/polyketide metabolite that requires experimental validation. While levan production within the lichen thallus and its ecological role remain unclear, this study establishes a valuable genomic foundation for future research on the biosynthetic potential of these bacteria, offering promising prospects for industrial applications and biotechnological development.