Carbohydrate-based drugs launched during 2000-2021

Regiodivergent Functionalization of Protected and Unprotected Carbohydrates using Photoactive 4-Tetrafluoropyridinylthio Fragment as an Adaptive Activating Group

The selective functionalization of carbohydrates holds a central position in synthetic carbohydrate chemistry, driving the ongoing quest for ideal approaches to manipulate these compounds. In this study, we introduce a general strategy that enables the regiodivergent functionalization of saccharides. The use of electron-deficient photoactive 4-tetrafluoropyridinylthio (SPyf) fragment as an adaptable activating group, facilitated efficient functionalization across all saccharide sites. More importantly, this activating group can be directly installed at the C1, C5 and C6 positions of biomass-derived carbohydrates in a single step and in a site-selective manner, allowing for the efficient and precision-oriented modification of unprotected saccharides and glycans.

Mild and Effective Method for the Nickel-Catalyzed Arylation of Glycosyl Thiols in Aqueous Surfactant Solution

Aryl thioglycosides have broad applicability as both glycosyl donors and glycomimetic compounds. Their synthesis via the cross-coupling of glycosyl thiols with aryl halides has become a popular method for their construction because it allows better selectivity for anomeric configuration as well as a wider functional group tolerance compared to traditional methods. Herein, we report a nickel-catalyzed method for the synthesis of aryl thioglycosides which utilizes an aqueous micellar environment as the reaction medium. This alternative method allows for mild conditions while circumventing expensive palladium, leading to the successful synthesis of over 30 aryl thioglycosides, including challenging 1,2-cis thioglycoside products.

Stereoselective P(III)-Glycosylation for the Preparation of Phosphinated Sugars

Most of the reported work focus on the development of O-, N-, C- and S-glycosylation methods. However, no study explores P(III)-glycosylation reaction. Herein we describe a convenient protocol to realize P(III)-glycosylation process. A simple β-phosphino ester is adopted as P(III)-transfer reagent for this new type of glycosylation via a nucleophilic substitution and release strategy. Diverse phosphine units are introduced to the anomeric center of various sugars efficiently and with excellent stereoselectivity. The value of this method is showcased by the prepared P(III)-sugars as novel linkers in bioactive molecule conjugation, new chiral ligands in metal-catalyzed asymmetric allylic substitutions and organocatalysts. Preliminary mechanistic studies corroborated the designed P(III)-transfer process.

Photocatalyst-free light-promoted carbohydrate synthesis and modification

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.

Therapeutic applications of carbohydrate-based compounds: a sweet solution for medical advancement

Carbohydrates, one of the most abundant biomolecules found in nature, have been seen traditionally as a dietary component of foods. Recent findings, however, have unveiled their medicinal potential in the form of carbohydrates-derived drugs. Their remarkable structural diversity, high optical purity, bioavailability, low toxicity and the presence of multiple functional groups have positioned them as a valuable scaffold and an exciting frontier in contemporary therapeutics. At present, more than 170 carbohydrates-based therapeutics have been granted approval by varying regulatory agencies such as United States Food and Drug Administration (FDA), Japan Pharmaceuticals and Medical Devices Agency (PMDA), Chinese National Medical Products Administration (NMPA), and the European Medicines Agency (EMA). This article explores an overview of the fascinating potential and impact of carbohydrate-derived compounds as pharmacological agents and drug delivery vehicles.

Stereoselective chemical N-glycoconjugation of amines via CO2 incorporation

Chemical N-glycoconjugation can provide a unique way to tailor the properties of the ubiquitous amines for further expending their diverse functions and applications. Nevertheless, effective methodology for glycoconjugation of amines remains largely underdeveloped. Inspired by a biotransformation pathway of amine-containing drugs in vivo, we have developed an effective protocol that enables one-step chemical N-glycoconjugation of amines in high stereoselectivity under mild conditions. This protocol involves conversion of the amine moiety into the corresponding carbamate anion under CO2 atmosphere and a subsequent SN2 type reaction with glycosyl halides. This work provides an example of using CO2 as the coupling unit in chemical glycoconjugation reactions. A case study on the resulting N-glycoconjugates of Crizotinib, an anticancer drug, demonstrates a quick cleavage of the glucosyl carbamate linkage, testifying that this N-glyconjugation method could serve as a general approach to procure novel prodrugs.

Creating glycoside diversity through stereoselective carboboration of glycals

Site-specific modification of glycosides to enhance or alter the physiological properties of the parent molecule has become a highly attractive strategy in drug development. However, creating glycoside building blocks with multiple diversifiable positions from readily available sugar precursors remains a challenging task. Herein, we present a highly regio- and stereoselective nickel-catalyzed carboboration of glycals, which offers a platform for generating glycoside diversity with diverse C1 and C2 modification potential. Specially, the integration of a readily modifiable boronate group at the C2 position markedly amplifies the versatility of this approach, furnishing a universal method for swiftly generating diverse rare sugars with C2-site modifications through expedited downstream transformations. This method demonstrates a broad substrate scope and tolerates various functional groups and complex natural or drug molecular architectures. Moreover, we illustrate the synthetic potential of this method through the synthesis of a diverse array of analogs of both natural products and pharmaceuticals.

Development of Glycosylation Protocols Using Glycosyl N-Phenylethynyl Pyrrole-2-carboxylates as Donors

We herein introduce glycosyl N-phenylethynyl pyrrole-2-carboxylates (PEPCs) as novel and highly efficient glycosyl donors. The unique inclusion of the pyrrole group, serving as both an electron-donating group and an ortho-tethering scaffold, imparts exceptional shelf stability while retaining reactivity for glycosylation reactions. PEPC donors exhibit broad utility for both O- and N-glycosylation across a variety of substrates. Additionally, their versatility and efficiency were further demonstrated in a one-pot saccharide synthesis, showcasing their potential for diverse synthetic applications.

Visible-light-promoted direct desulfurization of glycosyl thiols to access C-glycosides

C-Glycosides are essential for the study of biological processes and the development of carbohydrate-based drugs. Despite the tremendous hurdles, glycochemists have often fantasized about the efficient, highly stereoselective synthesis of C-glycosides with the shortest steps under mild conditions. Herein, we report a desulfurative radical protocol to synthesize C-alkyl glycosides and coumarin C-glycosides under visible-light induced conditions without the need of an extra photocatalyst, in which stable and readily available glycosyl thiols that could be readily obtained from native sugars are activated in situ by pentafluoropyridine. The benefits of this procedure include high stereoselectivity, broad substrate scope, and easy handling. Mechanistic studies indicate that the in situ produced tetrafluoropyridyl S-glycosides form key electron donor-acceptor (EDA) complexes with Hantzsch ester (for C-alkyl glycosides) or Et3N (for coumarin C-glycosides), which, upon irradiation with visible light, trigger a cascade of glycosyl radical processes to access C-glycosides smoothly.

Emerging paradigms in Alzheimer's therapy

Alzheimer's disease is a neurodegenerative disorder that affects elderly, and its incidence is continuously increasing across the globe. Unfortunately, despite decades of research, a complete cure for Alzheimer's disease continues to elude us. The current medications are mainly symptomatic and slow the disease progression but do not result in reversal of all disease pathologies. The growing body of knowledge on the factors responsible for the onset and progression of the disease has resulted in the identification of new targets that could be targeted for treatment of Alzheimer's disease. This has opened new vistas for treatment of Alzheimer's disease that have moved away from chemotherapeutic agents modulating a single target to biologics and combinations that acted on multiple targets thereby offering better therapeutic outcomes. This review discusses the emerging directions in therapeutic interventions against Alzheimer's disease highlighting their merits that promise to change the treatment paradigm and challenges that limit their clinical translation.

Stereoselective and site-divergent synthesis of C-glycosides

Carbohydrates play important roles in medicinal chemistry and biochemistry. However, their synthesis relies on specially designed glycosyl donors, which are often unstable and require multi-step synthesis. Furthermore, the catalytic and stereoselective installation of arylated quaternary stereocentres on sugar rings remains a formidable challenge. Here we report a facile and versatile method for the synthesis of diverse C-R (where R is an aryl, heteroaryl, alkenyl, alkynyl or alkyl) glycosides from readily available and bench-stable 1-deoxyglycosides. The reaction proceeds under mild conditions and exhibits high stereoselectivity across a broad range of glycosyl units. This protocol can be used to synthesize challenging 2-deoxyglycosides, unprotected glycosides, non-classical glycosides and deuterated glycosides. We further developed the catalyst-controlled site-divergent functionalization of carbohydrates for the synthesis of various unexplored carbohydrates containing arylated quaternary stereocentres that are inaccessible by existing methods. The synthetic utility of this strategy is further demonstrated in the synthesis of pharmaceutically relevant molecules and carbohydrates.

Palladium-Catalyzed Regio- and Stereoselective Glycosylation of Azole Heterocycles Enables Access to Diverse Heterocyclic N-Glycosides

An efficient and practical glycosylation platform for synthesizing N-glycosides by leveraging palladium catalysis is disclosed. This approach enables facile access to diverse heterocyclic N-glycosides with excellent regio- and stereoselectivities and high site selectivity of multiple N atoms. The reaction exhibits a broad substrate scope (65 examples), high functional group tolerance, and easy scalability. Its synthetic utility is demonstrated through late-stage functionalization of pharmaceutically relevant molecules and various diastereoselective transformations of the glycoside products. Overall, our method provides a handy tool for efficient and stereocontrolled synthesis of valuable N-glycosylated heterocycles.

Synthesis of C-Alkyl Glycosides from Alkyl Bromides and Glycosyl Carboxylic Acids via Ni/Photoredox Dual Catalysis

C-Alkyl glycosides, an important class of C-glycosides, are widely found in various drugs and natural products. The synthesis of C-alkyl glycosides has attracted considerable attention. Herein, we developed a Ni/photoredox catalyzed decarboxylative C(sp3)-C(sp3) coupling reaction of stable glycosylcarboxylic acids with simple aliphatic bromides to generate C-alkyl glycosides. The method successfully linked several functional molecular fragments (natural products or drugs) to a sugar moiety, showing the extensive application prospects of this transformation. Controlled experiments and DFT calculations demonstrated that the reaction pathway contains a free radical process, and a possible mechanism is proposed.

Stereoselective Construction of Multifunctional C-Glycosides Enabled by Nickel-Catalyzed Tandem Borylation/Glycosylation

Stereochemically pure saccharides have indispensable roles in fields ranging from medicinal chemistry to materials science and organic synthesis. However, the development of a simple, stereoselective, and efficient glycosylation protocol to access α- and β-C-glycosides (particularly 2-deoxy entities) remains a persistent challenge. Existing studies have primarily focused on C1 modification of carbohydrates and transformation of glycosyl radical precursors. Here, we innovate by harnessing the in situ generated glycosyl-Ni species to achieve one-pot borylation and glycosylation in a cascade manner, which is enabled by an earth-abundant nickel-catalyzed carboboration of readily accessible glycals without any ligand. This work reveals the potential for the development of a modular and multifunctional glycosylation platform to facilitate the simultaneous introduction of C-C and C-B bonds at the stereogenic center of saccharides, a largely unexploited research area. Preliminary experimental and computational studies indicate that the endocyclic O and the C3 group play important roles in stereoseclectively forging glycosidic bonds. As a result, a diverse range of C-R (R = alkyl, aryl, and alkenyl) and 2-deoxygenated glycosides bearing modifiable boron groups could be rapidly made with excellent stereocontrol and exhibit remarkable functional group tolerance. The synthetic potential is underscored in the late-stage glycosylation of natural products and commercial drugs as well as the facile preparation of various rare sugars, bioactive conjugates, and key intermediates to prorocentin, phomonol, and aspergillide A.

Silicomolybdic Acid Cluster as Biocompatible Catalyst for One-Pot Tandem Synthesis of Orthogonally Protected Glycosides

The present paper describes a new and practical approach for the one-pot preparation of O-isopropylidene derivatives and also orthogonally protected S- and O-glycosides from the corresponding unprotected saccharides by employing 2 mol % of a silicomolybdic acid (SMA) cluster as a versatile and biocompatible catalyst. The present protocol is applicable to two-step one-pot tandem transformations, which include the O-isopropylidation, spiroketal functionalization, 4,6-O-arylidene acetalations, and arylidene acetylation processes under relatively mild reaction conditions. One-pot sequential transformations, low catalyst loading, rapid transformation, high to excellent reaction yields, mild reaction conditions, and a nontoxic biocompatible workup procedure are the notable advantages of devised protocol.

Pd-Catalyzed Coupling of Bromo-N- (β-glucopyranosyl)quinolin-2-ones with Amides: Synthesis of N-glucosyl-6BrCaQ Conjugates with Potent Anticancer Activity

A series of N-glycosyl- 6BrCaQ conjugates was synthesized through a Pd-catalyzed cross-coupling reaction between brominated N-glycosyl quinolin-2-one derivatives and various nitrogen nucleophiles. Antiproliferative assays revealed that this new series of analogues represents a promising class of antitumor compounds as illustrated by the high biological activity observed for several derivatives towards different cancer cell lines compared to the non-glycosylated congeners.

Stereocontrolled Synthesis of Aryl C-Nucleosides under Ambient Conditions

A stereocontrolled synthesis of an aryl C-nucleoside has been developed using D-ribals and arylboronic acids catalyzed by palladium without additional ligands in common solvents under an open-air atmosphere at room temperature. This protocol features very mild conditions, simplicity in operation, exclusive β-stereoselectivity, broad substrate scopes, and good compatibility with reactive amino and hydroxyl groups. The functionalization of unsaturated C-nucleosides and the late-stage glycosylation of natural products/drugs demonstrated the high practicality of this strategy.

Palladium-catalyzed Suzuki-Miyaura cross-couplings of stable glycal boronates for robust synthesis of C-1 glycals

C-1 Glycals serve as pivotal intermediates in synthesizing diverse C-glycosyl compounds and natural products, necessitating the development of concise, efficient and user-friendly methods to obtain C-1 glycosides is essential. The Suzuki-Miyaura cross-coupling of glycal boronates is notable for its reliability and non-toxic nature, but glycal donor stability remains a challenge. Herein, we achieve a significant breakthrough by developing stable glycal boronates, effectively overcoming the stability issue in glycal-based Suzuki-Miyaura coupling. Leveraging the balanced reactivity and stability of our glycal boronates, we establish a robust palladium-catalyzed glycal-based Suzuki-Miyaura reaction, facilitating the formation of various C(sp2)-C(sp), C(sp2)-C(sp2), and C(sp2)-C(sp3) bonds under mild conditions. Notably, we expand upon this achievement by developing the DNA-compatible glycal-based cross-coupling reaction to synthesize various glycal-DNA conjugates. With its excellent reaction reactivity, stability, generality, and ease of handling, the method holds promise for widespread appication in the preparation of C-glycosyl compounds and natural products.

Glycopolymer Inhibitors of Galectin-3 Suppress the Markers of Tissue Remodeling in Pulmonary Hypertension

Pulmonary hypertension is a cardiovascular disease with a low survival rate. The protein galectin-3 (Gal-3) binding β-galactosides of cellular glycoproteins plays an important role in the onset and development of this disease. Carbohydrate-based drugs that target Gal-3 represent a new therapeutic strategy in the treatment of pulmonary hypertension. Here, we present the synthesis of novel hydrophilic glycopolymer inhibitors of Gal-3 based on a polyoxazoline chain decorated with carbohydrate ligands. Biolayer interferometry revealed a high binding affinity of these glycopolymers to Gal-3 in the subnanomolar range. In the cell cultures of cardiac fibroblasts and pulmonary artery smooth muscle cells, the most potent glycopolymer 18 (Lac-high) caused a decrease in the expression of markers of tissue remodeling in pulmonary hypertension. The glycopolymers were shown to penetrate into the cells. In a biodistribution and pharmacokinetics study in rats, the glycopolymers accumulated in heart and lung tissues, which are most affected by pulmonary hypertension.

In vitro antimicrobial, anticancer evaluation, and in silico studies of mannopyranoside analogs against bacterial and fungal proteins: Acylation leads to improved antimicrobial activity

Carbohydrate analogs are an important, well-established class of clinically useful medicinal agents that exhibit potent antimicrobial activity. Thus, we explored the various therapeutic potential of methyl α-D-mannopyranoside (MαDM) analogs, including their ability to synthesize and assess their antibacterial, antifungal, and anticancer properties; additionally, molecular docking, molecular dynamics simulation, and ADMET analysis were performed. The structure of the synthesized MαDM analogs was ascertained by spectroscopic techniques and physicochemical and elemental analysis. In vitro antimicrobial activity was assessed and revealed significant inhibitory effects, particularly against gram-negative bacteria along with the prediction of activity spectra for substances (PASS). Concurrently, MαDM analogs showed good results against antifungal pathogens and exhibited promising anticancer effects in vitro, demonstrating dose-dependent cytotoxicity against Ehrlich ascites carcinoma (EAC) cancer cells while sparing normal cells from compound 5, with an IC50 of 4511.65 µg/mL according to the MTT colorimetric assay. A structure-activity relationship (SAR) study revealed that hexose combined with the acyl chains of decanoyl (C-10) and benzenesulfonyl (C6H5SO2-) had synergistic effects on the bacteria and fungi that were examined. Molecular docking was performed against the Escherichia coli (6KZV) and Candida albicans (1EAG) proteins to acquire insights into the molecular interactions underlying the observed biological activities. The docking results were further supported by 100 ns molecular dynamics simulations, which provided a dynamic view of the stability and flexibility of complexes involving MαDM and its targets. In addition, ADMET analysis was used to evaluate the toxicological and pharmacokinetic profiles. Owing to their promising drug-like properties, these MαDM analogs exhibit potential as prospective therapeutic candidates for future development.

Glucocorticoids-based prodrug design: Current strategies and research progress

Attributing to their broad pharmacological effects encompassing anti-inflammation, antitoxin, and immunosuppression, glucocorticoids (GCs) are extensively utilized in the clinic for the treatment of diverse diseases such as lupus erythematosus, nephritis, arthritis, ulcerative colitis, asthma, keratitis, macular edema, and leukemia. However, long-term use often causes undesirable side effects, including metabolic disorders-induced Cushing's syndrome (buffalo back, full moon face, hyperglycemia, etc.), osteoporosis, aggravated infection, psychosis, glaucoma, and cataract. These notorious side effects seriously compromise patients' quality of life, especially in patients with chronic diseases. Therefore, glucocorticoid-based advanced drug delivery systems for reducing adverse effects have received extensive attention. Among them, prodrugs have the advantages of low investment, low risk, and high success rate, making them a promising strategy. In this review, we propose the strategies for the design and summarize current research progress of glucocorticoid-based prodrugs in recent decades, including polymer-based prodrugs, dendrimer-based prodrugs, antibody-drug conjugates, peptide-drug conjugates, carbohydrate-based prodrugs, aliphatic acid-based prodrugs and so on. Besides, we also raise issues that need to be focused on during the development of glucocorticoid-based prodrugs. This review is expected to be helpful for the research and development of novel GCs and prodrugs.

The structures of two polysaccharides from Lepidium meyenii and their immunomodulatory effects via activating NF-κB signaling pathway

Lepidium meyenii Walp., also known as the "Peruvian national treasure", is a popular functional food in the daily lives of Peruvian people due to its bioactive with main polysaccharides. However, studies on polysaccharides isolated from Lepidium meyenii were few. Two new highly heterogeneous polysaccharides, MCP-1a and MCP-2b, were isolated and purified from the tuber of Lepidium meyenii. The structure characterization revealed that MCP-1a primarily consisted of D-Glc and had a molecular weight of 6.6 kDa. Its backbone was composed of 1,4,6-α-D-Glc, while branches feature T-α-L-Ara, 1,5-α-L-Ara, and T-α-D-Glc attached to the O-6 positions. MCP-2b was a rare arabinogalactan with a molecular weight of 49.4 kDa. Interestingly, the backbone of MCP-2b was composed of 1,6-β-D-Gal, 1,3,6-β-D-Gal with a few 1,3-β-D-GlcpA-4-OMe units inserted. Side chains of MCP-2b were mainly composed of 1,3-β-D-Gal, T-β-D-Gal, T-α-L-Ara, 1,5-α-L-Ara, with trace amounts of 1,4-β-D-Glc and T-β-D-Glc. The bioactivity assay results revealed that MCP-1a and MCP-2b increased the release of NO, IL-1β, TNF-α, and IL-6 from RAW 264.7 cells at concentrations ranging from 50 μg/mL to 400 μg/mL. Furthermore, MCP-1a and MCP-2b could promote the expression of key transcription factors (IκB-α, p-IκB-α, p65, and p-p65) in the NF-κB pathway, indicating that MCP-1a and MCP-2b had potential immunomodulatory activities.

Mitigating candidiasis with acarbose by targeting Candida albicans α-glucosidase: in-silico, in-vitro and transcriptomic approaches

Biofilm-associated candidiasis poses a significant challenge in clinical settings due to the limited effectiveness of existing antifungal treatments. The challenges include increased pathogen virulence, multi-drug resistance, and inadequate penetration of antimicrobials into biofilm structures. One potential solution to this problem involves the development of novel drugs that can modulate fungal virulence and biofilm formation, which is essential for pathogenesis. Resistance in Candida albicans is initiated by morphological changes from yeast to hyphal form. This transition triggers a series of events such as cell wall elongation, increased adhesion, invasion of host tissues, pathogenicity, biofilm formation, and the initiation of an immune response. The cell wall is a critical interface for interactions with host cells, primarily through various cell wall proteins, particularly mannoproteins. Thus, cell wall proteins and enzymes are considered potential antifungal targets. In this regard, we explored α-glucosidase as our potential target which plays a crucial role in processing mannoproteins. Previous studies have shown that inhibition of α-glucosidase leads to defects in cell wall integrity, reduced adhesion, diminished secretion of hydrolytic enzymes, alterations in immune recognition, and reduced pathogenicity. Since α-glucosidase, primarily converts carbohydrates, our study focuses on FDA-approved carbohydrate mimic drugs (Glycomimetics) with well-documented applications in various biological contexts. Through virtual screening of 114 FDA-approved carbohydrate-based drugs, a pseudo-sugar Acarbose, emerged as a top hit. Acarbose is known for its pharmacological potential in managing type 2 diabetes mellitus by targeting α-glucosidase. Our preliminary investigations indicate that Acarbose effectively inhibits C. albicans biofilm formation, reduces virulence, impairs morphological switching, and hinders the adhesion and invasion of host cells, all at very low concentrations in the nanomolar range. Furthermore, transcriptomic analysis reveals the mechanism of action of Acarbose, highlighting its role in targeting α-glucosidase.

Benzoxaborole Catalyst Embedded with a Lewis Base: A Highly Active and Selective Catalyst for cis-1,2-diol Modification

The regioselective modification of polyols allows rapid access to their derivatives, thereby accelerating the polyol-related biology and drug discovery. We previously reported that benzoxaborole is a potent catalyst for the regioselective modification of polyols containing a cis-1,2-diol structure. In this study, we developed a bifunctional benzoxaborole catalyst embedded with a Lewis base. Benzoxaborole and Lewis base groups were designed to cooperatively activate a substrate (cis-1,2-diol) and reactant (electrophile), respectively, hence lowering the reaction barrier for the cis-1,2-diol moiety. The bifunctional catalyst indeed exhibited a significantly higher catalytic activity and selectivity for cis-1,2-diol modifications rather than a benzoxaborole catalyst without a Lewis base group. Mechanistic analyses, using both experimental and theoretical methods, supported the design of our catalyst. The bifunctional catalyst reported herein would be a new tool for the straightforward synthesis of polyol derivatives.

Microwave-assisted synthesis of highly sulfated mannuronate glycans as potential inhibitors against SARS-CoV-2

Algae-based marine carbohydrate drugs are typically decorated with negative ion groups such as carboxylate and sulfate groups. However, the precise synthesis of highly sulfated alginates is challenging, thus impeding their structure-activity relationship studies. Herein we achieve a microwave-assisted synthesis of a range of highly sulfated mannuronate glycans with up to 17 sulfation sites by overcoming the incomplete sulfation due to the electrostatic repulsion of crowded polyanionic groups. Although the partially sulfated tetrasaccharide had the highest affinity for the receptor binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant, the fully sulfated octasaccharide showed the most potent interference with the binding of the RBD to angiotensin-converting enzyme 2 (ACE2) and Vero E6 cells, indicating that the sulfated oligosaccharides might inhibit the RBD binding to ACE2 in a length-dependent manner.

Direct Identification of Complex Glycans via a Highly Sensitive Engineered Nanopore

The crucial roles that glycans play in biological systems are determined by their structures. However, the analysis of glycan structures still has numerous bottlenecks due to their inherent complexities. The nanopore technology has emerged as a powerful sensor for DNA sequencing and peptide detection. This has a significant impact on the development of a related research area. Currently, nanopores are beginning to be applied for the detection of simple glycans, but the analysis of complex glycans by this technology is still challenging. Here, we designed an engineered α-hemolysin nanopore M113R/T115A to achieve the sensing of complex glycans at micromolar concentrations and under label-free conditions. By extracting characteristic features to depict a three-dimensional (3D) scatter plot, glycans with different numbers of functional groups, various chain lengths ranging from disaccharide to decasaccharide, and distinct glycosidic linkages could be distinguished. Molecular dynamics (MD) simulations show different behaviors of glycans with β1,3- or β1,4-glycosidic bonds in nanopores. More importantly, the designed nanopore system permitted the discrimination of each glycan isomer with different lengths in a mixture with a separation ratio of over 0.9. This work represents a proof-of-concept demonstration that complex glycans can be analyzed using nanopore sequencing technology.

Precise Structural Analysis of Neutral Glycans Using Aerolysin Mutant T240R Nanopore

Glycans play vital roles in nearly all life processes of multicellular organisms, and understanding these activities is inseparable from elucidating the biological significance of glycans. However, glycan research has lagged behind that of DNA and protein due to the challenges posed by structural heterogeneity and isomerism (i.e., structures with equal molecular weights) the lack of high-efficiency structural analysis techniques. Nanopore technology has emerged as a sensitive single-molecule biosensor, shining a light on glycan analysis. However, a significant number of glycans are small and uncharged, making it challenging to elicit identifiable nanopore signals. Here we introduce a R-binaphthyl tag into glycans, which enhances the cation-π interaction between the derivatized glycan molecules and the nanopore interface, enabling the detection of neutral glycans with an aerolysin nanopore. This approach allows for the distinction of di-, tri-, and tetrasaccharides with monosaccharide resolution and has the potential for group discrimination, the monitoring of enzymatic transglycosylation reactions. Notably, the aerolysin mutant T240R achieves unambiguous identification of six disaccharide isomers, trisaccharide and tetrasaccharide linkage isomers. Molecular docking simulations reveal that multiple noncovalent interactions occur between residues R282, K238, and R240 and the glycans and R-binaphthyl tag, significantly slowing down their translocation across the nanopore. Importantly, we provide a demonstration of the kinetic translocation process of neutral glycan isomers, establishing a solid theoretical foundation for glycan nanopore analysis. The development of our technology could promote the analysis of glycan structural isomers and has the potential for nanopore-based glycan structural determination and sequencing.

Nanopore-based glycan sequencing: state of the art and future prospects

Sequencing of biomacromolecules is a crucial cornerstone in life sciences. Glycans, one of the fundamental biomolecules, derive their physiological and pathological functions from their structures. Glycan sequencing faces challenges due to its structural complexity and current detection technology limitations. As a highly sensitive sensor, nanopores can directly convert nucleic acid sequence information into electrical signals, spearheading the revolution of third-generation nucleic acid sequencing technologies. However, their potential for deciphering complex glycans remains untapped. Initial attempts demonstrated the significant sensitivity of nanopores in glycan sensing, which provided the theoretical basis and insights for the realization of nanopore-based glycan sequencing. Here, we present three potential technical routes to employ nanopore technology in glycan sequencing for the first time. The three novel technical routes include: strand sequencing, capturing glycan chains as they translocate through nanopores; sequential hydrolysis sequencing, capturing released monosaccharides one by one; splicing sequencing, mapping signals from hydrolyzed glycan fragments to an oligosaccharide database/library. Designing suitable nanopores, enzymes, and motors, and extracting characteristic signals pose major challenges, potentially aided by artificial intelligence. It would be highly desirable to design an all-in-one high-throughput glycan sequencer instrument by integrating a sample processing unit, nanopore array, and signal acquisition system into a microfluidic device. The nanopore sequencer invention calls for intensive multidisciplinary cooperation including electrochemistry, glycochemistry, engineering, materials, enzymology, etc. Advancing glycan sequencing will promote the development of basic research and facilitate the discovery of glycan-based drugs and disease markers, fostering progress in glycoscience and even life sciences.

Dehydroxylative radical N-glycosylation of heterocycles with 1-hydroxycarbohydrates enabled by copper metallaphotoredox catalysis

N-Glycosylated heterocycles play important roles in biological systems and drug development. The synthesis of these compounds heavily relies on ionic N-glycosylation, which is usually constrained by factors such as labile glycosyl donors, precious metal catalysts, and stringent conditions. Herein, we report a dehydroxylative radical method for synthesizing N-glycosides by leveraging copper metallaphotoredox catalysis, in which stable and readily available 1-hydroxy carbohydrates are activated for direct N-glycosylation. Our method employs inexpensive photo- and copper- catalysts and can tolerate some extent of water. The reaction exhibits a broad substrate scope, encompassing 76 examples, and demonstrates high stereoselectivity, favoring 1,2-trans selectivity for furanoses and α-selectivity for pyranoses. It also exhibits high site-selectivity for substrates containing multiple N-atoms. The synthetic utility is showcased through the late-stage functionalization of bioactive compounds and pharmaceuticals like Olaparib, Axitinib, and Metaxalone. Mechanistic studies prove the presence of glycosyl radicals and the importance of copper metallaphotoredox catalysis.

Carbohydrate-DNA Conjugation Enabled by Glycosyl Radicals Generated from Glycosyl Sulfinates

Herein, we report a method that enables the synthesis of carbohydrate-DNA conjugates by radical addition. Key to the success is the use of readily available, bench-stable, and unprotected glycosyl sulfinates as precursors to glycosyl radicals. The redox neutral reaction proceeds under mild and simple conditions and tolerates a broad substrate scope. A small library of carbohydrate-DNA conjugates was prepared.

Recent Progress in Human Milk Oligosaccharides and Its Antiviral Efficacy

Gastrointestinal (GI)-associated viruses, including rotavirus (RV), norovirus (NV), and enterovirus, usually invade host cells, transmit, and mutate their genetic information, resulting in influenza-like symptoms, acute gastroenteritis, encephalitis, or even death. The unique structures of human milk oligosaccharides (HMOs) enable them to shape the gut microbial diversity and endogenous immune system of human infants. Growing evidence suggests that HMOs can enhance host resistance to GI-associated viruses but without a systematic summary to review the mechanism. The present review examines the lactose- and neutral-core HMOs and their antiviral effects in the host. The potential negative impacts of enterovirus 71 (EV-A71) and other GI viruses on children are extensive and include neurological sequelae, neurodevelopmental retardation, and cognitive decline. However, the differences in the binding affinity of HMOs for GI viruses are vast. Hence, elucidating the mechanisms and positive effects of HMOs against different viruses may facilitate the development of novel HMO derived oligosaccharides.

Regioselective Deacetylation of Peracetylated Deoxy-C-glycopyranosides by Boron Trichloride (BCl3)

A general approach for regioselective deacetylation at sugar 3-OH of peracetylated 6-deoxy-C-glucopyranosides mediated by BCl3 was developed. The approach could be extended to other sugar-derived 6-deoxy-C-glycopyranosides, such as those derived from mannose, galactose, and rhamnose, with deacetylation occurring at varied sugar hydroxyl groups, and further extended to 4-deoxy-C-glucopyranosides with deacetylation occurring at sugar 3-OH. The approach would enable access to synthetically challenging carbohydrate derivatives. A possible mechanism of the regioselectivity was proposed.

Structural characterization, molecular dynamic simulation, and conformational visualization of a water-soluble glucan with high molecular weight from Gastrodia elata Blume

Polysaccharides have been widely used in the development of natural drugs and health food. However, polysaccharide characterization lags due to inherently complicated features and the limitations of existing detection approaches. We aimed to provide new insight into the fine structure and conformational visualization of polysaccharides from Gastrodia elata Blume, a medicinal and edible plant. A water-soluble polysaccharide (GEP2-6) with the high molecular weight of 2.7 × 106 Da was first obtained, and its purity reached 99.2 %. Chemical and spectroscopic analyses jointly revealed that GEP2-6 was a glucan linked by α-(1 → 4) and α-(1 → 6) glycosidic bonds. After enzymolysis, the local structure of GEP2-6 included α-1,4-Glcp, α-1,6-Glcp, α-1,4,6-Glcp, and α-1-Glcp at a molar ratio of 31.27∶1.32∶1.08∶0.93. The glycosidic linkage pattern of repeating units was further simulated by a glycan database and spatial examination software. The good dissolution performance was interpreted by dynamics simulation and practical molecular characteristics. Spherical flexible chains and the porous stable conformation were corroborated using atomic force microscopy. In addition, GEP2-6 could effectively scavenge DPPH and hydroxyl radicals as a promising natural antioxidant. These efforts will contribute to the expansion of clinical applications of this G. elata polysaccharide and the structural elucidation for macromolecular polysaccharides combined with traditional and modern analysis techniques.

Recent developments on the synthesis of biologically active glycohybrids

The exploration of hybridization emerges as a potent tool in advancing drug discovery research, with a significant emphasis on carbohydrate-containing hybrid scaffolds. Evidence indicates that linking carbohydrate molecules to privileged bioactive scaffolds enhances the bioactivity of drug molecules. This synergy results in a diverse range of activities, making carbohydrate scaffolds pivotal for synthesizing compound libraries with significant functional and structural diversity. Beyond their synthesis utility, these scaffolds offer applications in screening bioactive molecules, presenting alternative avenues for drug development. This comprehensive review spanning 2015 to 2023 focuses on synthesized glycohybrid molecules, revealing their bioactivity in areas such as anti-microbial, anti-cancer, anti-diabetic, anti-inflammatory activities, enzyme inhibition and pesticides. Numerous novel glycohybrids surpass positive control drugs in biological activity. This focused study not only highlights the diverse bioactivities of glycohybrids but also underscores their promising role in innovative drug development strategies.

Synthesis and cytotoxic evaluation of glycosyl derivatives of icaritin

A series of glycosyl alkyl/triazol-linked icaritin derivatives have been designed and synthesised. The target glycosyl derivatives were evaluated for their anticancer activity against three human cancer cell lines. The results of preliminary anticancer tests in vitro revealed that mannose derivatives 10a-10c (100 μM) with different aliphatic chain lengths exhibited increased cytotoxicity against HepG2 and SK-OV-3 cells compared with the parent compound icaritin. The data indicated that the kind of glycosyl groups and linkers affected the anticancer potency significantly. The ADME analysis of derivatives 10a-10c was also performed.

Direct Synthesis of α- and β-2'-Deoxynucleosides with Stereodirecting Phosphine Oxide via Remote Participation

2'-Deoxynucleosides and analogues play a vital role in drug development, but their preparation remains a significant challenge. Previous studies have focused on β-2'-deoxynucleosides with the natural β-configuration. In fact, their isomeric α-2'-deoxynucleosides also exhibit diverse bioactivities and even better metabolic stability. Herein, we report that both α- and β-2'-deoxynucleosides can be prepared with high yields and stereoselectivity using a remote directing diphenylphosphinoyl (DPP) group. It is particularly efficient to prepare α-2'-deoxynucleosides with an easily accessible 3,5-di-ODPP donor. Instead of acting as a H-bond acceptor on a 2-(diphenylphosphinoyl)acetyl (DPPA) group in our previous studies for syn-facial O-glycosylation, the phosphine oxide moiety here acts as a remote participating group to enable highly antifacial N-glycosylation. This proposed remote participation mechanism is supported by our first characterization of an important 1,5-briged P-heterobicyclic intermediate via variable-temperature NMR spectroscopy. Interestingly, antiproliferative assays led to a α-2'-deoxynucleoside with IC50 values in the low micromole range against central nervous system tumor cell lines SH-SY5Y and LN229, whereas its β-anomer exhibited no inhibition at 100 μM. Furthermore, the DPP group significantly enhanced the antitumor activities by 10 times.

Controllable 1,3-Bis-Functionalization of 2-Nitroglycals with High Regioselectivity and Stereoselectivity Enabled by a H-Bond Catalyst

The selective modification of carbohydrates is significant for producing their unnatural analogues for drug discovery. C1-functionalization (glycosylation) and C1,C2-difunctionalization of carbohydrates have been well developed. In contrast, C3-functionalization or C1,C3-difunctionalization of carbohydrates remains rare. Herein, we report such processes that efficiently and stereoselectively modify carbohydrates. Specifically, we found that trifluoroethanol (TFE) could promote 1,3-bis-indolylation/pyrrolylation of 2-nitroglycals generated carbohydrate derivatives in up to 93% yield at room temperature; slightly reducing the temperature could install two different indoles at the C1- and C3-positions. Switching TFE to a bifunctional amino thiourea catalyst leads to the generation of C3 monosubstituted carbohydrates, which could also be used to construct 1,3-di-C-functionalized carbohydrates. This approach produced a range of challenging sugar derivatives (over 80 examples) with controllable and high stereoselectivity (single isomer for over 90% of the examples). The potential applications of the reaction were demonstrated by a set of transformations including the synthesis of bridged large-ring molecules and gram scale reactions. Biological activities evaluation demonstrated that three compounds exhibit a potent inhibitory effect on human cancer cells T24, HCT116, AGS, and MKN-45 with IC50 ranged from 0.695 to 3.548 μM.

Total synthesis and cytotoxicity evaluation of the spirostanol saponin gitonin

The spirostanol saponin gitonin was efficiently synthesized in 12 steps (longest linear sequence) in 18.5% overall yield from the commercially available isopropyl β-D-1-thiogalactopyranoside (IPTG) and tigogenin. A cascade two-step glycosylation and Schmidt's inverse procedure significantly facilitated the synthesis of gitonin and its derivatives. The cytotoxic activities of gitonin and its structural analogues were evaluated against A549, HepG2, and MCF-7, and most of them exhibited moderate to excellent inhibitory activity. Our study demonstrates that the removal of the β-D-galactopyranosyl residue (attached at C-2 of the glucose unit) from gitonin would not decrease the inhibition activities; however, further cleavage of sugar units could seriously reduce the activities. A bioassay on these cancer cell lines also suggested that the presence of 2α-hydroxy on the aglycone weakened the cytotoxicity of the designed saponin.

Synthesis of C-Oligosaccharides via Ni-Catalyzed Reductive Hydroglycosylation

C-Oligosaccharides are metabolically stable surrogates of native glycans containing O/N/S-glycosidic linkages and thus have therapeutic potential. Here we report a straightforward approach to the synthesis of vinyl C-linked oligosaccharides via the Ni-catalyzed reductive hydroglycosylation of alkynyl glycosides with glycosyl bromides.

Direct Construction of C-Alkyl Glycosides from Non-Activated Olefins via Nickel-Catalyzed C(sp3)─C(sp3) Coupling Reaction

Among C-glycosides, C-alkyl glycosides are significant building blocks for natural products and glycopeptides. However, research on efficient construction methods for C-alkyl glycosides remains relatively limited. Compared with Michael acceptors, non-activated olefins are more challenging substrates and have rarely been employed in the construction of C-glycosides. Here, a highly efficient and convenient approach for the synthesis of C-alkyl glycosides through a nickel-catalyzed C(sp3)-C(sp3) coupling reaction is presented. A distinctive feature of this method is its utilization of non-activated olefins as the anomeric radical acceptors for hydroalkylation, allowing for the direct formation of C-glycoside bonds in a single step. Furthermore, this method demonstrates excellent compatibility with a broad scope of highly reactive functional groups. Mechanistic investigations suggest that the reaction proceeds via a free radical pathway, leading predominantly to the formation of products with α-configuration. Overall, this innovative methodology offers a versatile and practical approach for the synthesis of C-alkyl glycosides, offering new avenues for the production of intricate glycosides with potential applications in drug discovery and chemical biology.

Biosynthesis of Epipyrone A Reveals a Highly Specific Membrane-Bound Fungal C-Glycosyltransferase for Pyrone Galactosylation

Epipyrone A is a unique C-galactosylated 4-hydroxy-2-pyrone derivative with an antifungal potential from the fungus Epicoccum nigrum. We elucidated its biosynthesis via heterologous expression and characterized an unprecedented membrane-bound pyrone C-glycosyltransferase biochemically. Molecular docking and mutagenesis experiments suggested a possible mechanism for the heterocyclic C-glycosylation and the importance of a transmembrane helix for its catalysis. These results expand the repertoire of C-glycosyltransferases and provide new insights into the formation of C-glycosides in fungi.

Fe(III)-catalyzed stereoselective synthesis of deoxyglycosides using stable bifunctional deoxy-phenylpropiolate glycoside donors

Herein, we report a mild and economical route for the stereoselective synthesis of 2-deoxy and 2,6-dideoxyglycosides via FeCl3-catalyzed activation of bench stable deoxy-phenylpropiolate glycosyl donors (D-PPGs). Optimized reaction conditions work well under additive-free conditions to afford the corresponding 2-deoxy and 2,6-dideoxyglycosides in good yields with high α-anomeric selectivity by reacting with sugar and non-sugar-based acceptors. The optimized conditions were also extended for disarmed D-PPG donors. In addition, the developed strategy is amenable to high-scale-up synthesis.

Recent antibacterial carbohydrate-based prodrugs, drugs and delivery systems to overcome antimicrobial resistance

Antimicrobial resistance is an increasing phenomenon that is threatening global health. Tuberculosis causative bacteria and several resistant and multidrug-resistant bacteria are widely spread and listed by the World Health Organization as global priorities for research and development. Hence, new antibacterial agents with new modes of action are urgently required. In this context, carbohydrate-based drugs have been extensively studied and used, presenting several benefits for therapeutical purposes. In this review, the latest efforts done in the carbohydrate-based antibacterial agents research field, reported from 2021 to 2023, are summarized. Carbohydrate-based prodrugs, drugs, and delivery systems are covered, highlighting derivatization of existing antibiotics, use of nanotechnology, and repurposing of available therapeutical agents as the most popular strategies used in antibacterial agents' development.

An integrated strategy for rapid discovery and identification of the potential effective fragments of polysaccharides from Saposhnikoviae Radix

ETHNOPHARMACOLOGICAL RELEVANCE

Saposhnikoviae Radix (SR) is a traditional Chinese medicine, known as "Fangfeng". As one of the main active components, Saposhnikoviae Radix polysaccharides (SP) demonstrated a range of biological activities, especially immunity regulation activity.

AIMS OF THE STUDY

This study aimed at exploring whether polysaccharides have activity after degradation, then discovering the potential effective fragments of SP.

MATERIALS AND METHODS

Here we establish the chromatographic fingerprints method for 32 batches of 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatives of oligosaccharides by HPLC, meanwhile evaluating its immunomodulatory activity in vivo. Then, the potential effective fragments of SP were screened out based on the spectrum-effect relationship analysis between fingerprints and the pharmacological results. Besides, liquid chromatography ion trap-time of flight mass spectrometry (LC-IT-TOF MS) coupled with multiple data-mining techniques was used to identify the potential effective oligosaccharides.

RESULTS

These findings showed that the hydrolysate of SP have significant immunomodulatory, and the immunity regulation activity varies under different hydrolysis conditions. The 4 potential effective peaks of the hydrolysate of SP were mined by spectrum-effect relationship. Finally, the chemical structure of 4 potential effective oligosaccharide fragments of SP was elucidated based on LC-IT-TOF MS. F10 was inferred tentatively to be Hex1→6Hex1→6Hex1→6Hex1→6Hex1→6Gal; F18 was confirmed to be Rhamnose; F14 was inferred tentatively to be Hex1→4Hex1→ 4Hex1→4Gal and F25 was tentatively inferred to be Ara1→6Gal.

CONCLUSIONS

This study may provide a sound experimental foundation in the exploration of the active fragments from macromolecular components with relatively complex structures such as polysaccharides.

Site-Selective C-O Bond Editing of Unprotected Saccharides

Glucose and its polyhydroxy saccharide analogs are complex molecules that serve as essential structural components in biomacromolecules, natural products, medicines, and agrochemicals. Within the expansive realm of saccharides, a significant area of research revolves around chemically transforming naturally abundant saccharide units to intricate or uncommon molecules such as oligosaccharides or rare sugars. However, partly due to the presence of multiple hydroxyl groups with similar reactivities and the structural complexities arising from stereochemistry, the transformation of unprotected sugars to the desired target molecules remains challenging. One such formidable challenge lies in the efficient and selective activation and modification of the C-O bonds in saccharides. In this study, we disclose a modular 2-fold "tagging-editing" strategy that allows for direct and selective editing of C-O bonds of saccharides, enabling rapid preparation of valuable molecules such as rare sugars and drug derivatives. The first step, referred to as "tagging", involves catalytic site-selective installation of a photoredox active carboxylic ester group to a specific hydroxyl unit of an unprotected sugar. The second step, namely, "editing", features a C-O bond cleavage to form a carbon radical intermediate that undergoes further transformations such as C-H and C-C bond formations. Our strategy constitutes the most effective and shortest route in direct transformation and modification of medicines and other molecules bearing unprotected sugars.

Stereocontrolled Synthesis of α-3-Deoxy-d-manno-oct-2-ulosonic Acid (α-Kdo) Glycosides Using C3-p-Tolylthio-Substituted Kdo Donors: Access to Highly Branched Kdo Oligosaccharides

3-Deoxy-d-manno-oct-2-ulosonic acid (Kdo) is an eight-carbon monosaccharide found widely in bacterial lipopolysaccharides (LPSs) and capsule polysaccharides (CPSs). We developed an indirect method for the stereoselective synthesis of α-Kdo glycosides with a C3-p-tolylthio-substituted Kdo phosphite donor. The presence of the p-tolylthio group enhanced the reactivity, suppressed the formation of elimination by-products (2,3-enes), and provided complete α-stereocontrol. A variety of Kdo α-glycosides were synthesized by our method in excellent yields (up to 98 %). After glycosylation, the p-tolylthio group can be efficiently removed by free-radical reduction. Subsequently, the orthogonality of the phosphite donor and thioglycoside donor was demonstrated by the one-pot synthesis of a trisaccharide in Helicobacter pylori and Neisseria meningitidis LPS. Moreover, an efficient total synthesis route to the challenging 4,5-branched Kdo trisaccharide in LPSs from several A. baumannii strains was highlighted. To demonstrate the high reactivity of our approach further, the highly crowded 4,5,7,8-branched Kdo pentasaccharide was synthesized as a model molecule for the first time. Additionally, the reaction mechanism was investigated by DFT calculations.

Copper-catalyzed synthesis of pyrazolo[1,5-a]pyrimidine based triazole-linked glycohybrids: mechanistic insights and bio-applications

Hybrid molecules maintain their stronghold in the drug market, with over 60% of drug candidates in pharmaceutical industries. The substantial expenses for developing and producing biologically privileged drugs are expected to create opportunities for producing hybrid molecule-based drugs. Therefore, we have developed a simple and efficient copper-catalyzed approach for synthesizing a wide range of triazole-linked glycohybrids derived from pyrazolo[1,5-a]pyrimidines. Employing a microwave-assisted copper-catalyzed approach, we developed a concise route using various 7-O-propargylated pyrazolo[1,5-a]pyrimidines and 1-azidoglycosides. This strategy afforded a series of twenty-seven glycohybrids up to 98% yield with diverse stereochemistry. All were achieved within a remarkably shortened time frame. Our investigation extends to evaluating the anticancer potential of these synthesized triazole-linked pyrazolo[1,5-a] pyrimidine-based glycohybrids. In-vitro assays against MCF-7, MDA-MB231, and MDA-MB453 cell lines reveal intriguing findings. (2R,3S,4S,5R,6R)-2-(acetoxymethyl)-6-(4-(((5-(4-chlorophenyl)pyrazolo[1,5-a]pyrimidin-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate emerges as a standout with better anticancer activity against MDA-MB231 cells (IC50 = 29.1 µM), while (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-(4-(((5-(4-chlorophenyl)pyrazolo[1,5-a]pyrimidin-7-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate demonstrates the best inhibitory effects against MCF-7 cells (IC50 = 15.3 µM) in all derived compounds. These results align with our docking analysis and structure-activity relationship (SAR) investigations, further validating the in-vitro outcomes. This work not only underscores the synthetic utility of our devised protocol but also highlights the promising potential of these glycohybrids as candidates for further anticancer therapeutic exploration.

Exploring the diverse applications of Carbohydrate macromolecules in food, pharmaceutical, and environmental technologies

Carbohydrates are a class of macromolecules that has significant potential across several domains, including the organisation of genetic material, provision of structural support, and facilitation of defence mechanisms against invasion. Their molecular diversity enables a vast array of essential functions, such as energy storage, immunological signalling, and the modification of food texture and consistency. Due to their rheological characteristics, solubility, sweetness, hygroscopicity, ability to prevent crystallization, flavour encapsulation, and coating capabilities, carbohydrates are useful in food products. Carbohydrates hold potential for the future of therapeutic development due to their important role in sustained drug release, drug targeting, immune antigens, and adjuvants. Bio-based packaging provides an emerging phase of materials that offer biodegradability and biocompatibility, serving as a substitute for traditional non-biodegradable polymers used as coatings on paper. Blending polyhydroxyalkanoates (PHA) with carbohydrate biopolymers, such as starch, cellulose, polylactic acid, etc., reduces the undesirable qualities of PHA, such as crystallinity and brittleness, and enhances the PHA's properties in addition to minimizing manufacturing costs. Carbohydrate-based biopolymeric nanoparticles are a viable and cost-effective way to boost agricultural yields, which is crucial for the increasing global population. The use of biopolymeric nanoparticles derived from carbohydrates is a potential and economically viable approach to enhance the quality and quantity of agricultural harvests, which is of utmost importance given the developing global population. The carbohydrate biopolymers may play in plant protection against pathogenic fungi by inhibiting spore germination and mycelial growth, may act as effective elicitors inducing the plant immune system to cope with pathogens. Furthermore, they can be utilised as carriers in controlled-release formulations of agrochemicals or other active ingredients, offering an alternative approach to conventional fungicides. It is expected that this review provides an extensive summary of the application of carbohydrates in the realms of food, pharmaceuticals, and environment.

Chiral Discrimination of Monosaccharides Derivatized with 2-Fluorophenyl Hydrazine Using 19F NMR Spectroscopy

Chiral discrimination of monosaccharides holds significant importance, especially given the growing interest of the pharmaceutical industry in their utilization. However, the majority of existing methods has predominantly centered around chromatographic techniques. In this study, we introduce a 19F NMR-based comprehensive approach for chiral analysis specifically tailored for 15 pairs of aldoses. This technique involves employing sugar hydrazones containing fluorine in combination with chiral octahedral gallium and scandium complexes. By utilizing highly sensitive 19F NMR spectroscopy, the fluorine label in the sugar hydrazone enables accurate differentiation between d and l enantiomers. The efficiency of the newly developed method was demonstrated through its successful application in both quantitative and qualitative analyses of mixtures containing various monosaccharides.

Isolation and structural elucidation of prebiotic oligosaccharides from Ziziphi Spinosae Semen

Six oligosaccharides were discovered and isolated for the first time from Ziziphi Spinosae Semen. On the basis of spectroscopic analysis, their structures were determined to be verbascose (1), verbascotetraose (2), stachyose (3), manninotriose (4), raffinose (5), and melibiose (6). The prebiotic effect of the oligosaccharide fraction was assayed by eight gut bacterial growth in vitro, revealing a significant increase in cell density, up to 4-fold, for Lactobacillus acidophilus, Lactobacillus gasseri, and Lactobacillus johnsonii. The impact of six oligosaccharides with different degrees of polymerization (DPs) and structures on the growth of Lactobacillus acidophilus was evaluated. As a result, stachyose and raffinose demonstrated superior support for bacterial growth compared to the other oligosaccharides. This study explored the structure-activity relationship of raffinose family oligosaccharides (RFOs) and showed that the more the monosaccharide type, the more supportive the gut bacteria growth when oligosaccharides have the same molecular weight.