Search Results (6,390)

This study focuses on polysaccharides from Cistanche deserticola and Cistanche tubulosa, medicinal plants renowned for their health benefits. The “water extraction and alcohol precipitation” method was used to obtain the crude polysaccharides of the wine-making residues of C. deserticola (CDP) and C. tubulosa (CTP), respectively. Then, ultrafiltration membrane (UFM), DEAE-52, and Sephadex-G75 or Smartdex-G100 gel chromatography were used to separate and purify the crude polysaccharides, yielding the homogeneous fractions CDP1-5-1, CDP2-2-2, CDP2-3-2, CTP1-5-1, and CTP1-5-3. Structural analysis was conducted by using Fourier-transform infrared spectroscopy (FT-IR), high-performance anion-exchange chromatography coupled with multi-angle laser light scattering and refractive index detection (HPAEC-MALLS-RID), gas chromatography–mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), congo red, and scanning electron microscopy (SEM). CDP1-5-1 was found to be an arabinan, while CDP2-2-2 and CDP2-3-2 were agavin-like fructans with different molecular weights. CTP1-5-1 and CTP1-5-3 were identified as a heteropolysaccharide and a galacturonan, respectively. Immunological evaluation using RAW264.7 macrophages showed that they all significantly enhanced nitric oxide (NO) production, with CDP1-5-1 exhibiting the most potent activity. The structural–activity relationship is summarized as follows: the arabinose was a key active unit with NO stimulatory effects. This research provides foundational data on the structure and immune-enhancing potential of Cistanche polysaccharides, supporting their further development and application. Full article

Gold nanoparticles (AuNPs) are promising for biomedical applications, but their synthesis often requires toxic reagents. “Green” methods utilizing biopolymers offer a sustainable alternative. This study presents a novel synthesis of stable gold nanoparticles using a disulfide-crosslinked derivative of alginic acid (AA–S–S–AA) as both a reducing agent and stabilizer. The S–S-cross-linked alginate was synthesized with a degree of substitution of ~4.2% and reacted with HAuCl₄ in water at room temperature for just 10 min to give stable and polysaccharide in situ modified gold nanoparticles (AA-AuNPs). The resulting AA-AuNPs were characterized by a surface plasmon resonance peak at 539 nm and exhibited good colloidal stability over 14 days. Electron microscopy revealed spherical nanoparticles with a bimodal size distribution (10 nm and 75–100 nm) and a visible polysaccharide shell (5–9 nm), confirming effective stabilization. X-ray photoelectron spectroscopy confirmed the presence of metallic gold (Au⁰) and Au¹⁺. NMR analysis indicated the oxidation of disulfide groups to sulfonic acid during synthesis. The nanoparticles demonstrated a high negative zeta-potential of −53.9 mV, attributable to the polyanionic alginate corona, ensuring strong electrostatic stabilization. This work establishes sulfur-modified alginic acid as an efficient platform for the rapid synthesis of stable, hybrid nanoparticles for potential use in catalysis and biomedicine. Full article

The agar is an important polysaccharide widely used in the food industry, pharmaceuticals, cosmetics, microbiology, and molecular biology applications. The global demand for agar polysaccharide is steadily rising, but its production is limited due to shortage of good raw material. This research investigates the potential of Gelidium micropterum as an alternative and sustainable source of high-quality agar. Agar was extracted using different concentrations of NaOH (4, 6, 8, and 10% w/v) and without NaOH treatment. The resulting agar yields ranged from 16.97% to 26.03%, with corresponding gel strengths between 855 ± 51 and 2078 ± 55 g/cm². Notably, 8% and 10% NaOH pre-treatments yielded agar with superior gel strength and thermal properties, surpassing those reported for other Gelidiales species under similar conditions. Structural characterisation was performed using FT-IR, ¹³C-NMR, and ¹H-NMR spectroscopy, confirming similarities with standard agar. The extracted agar’s molecular weights were in the range of 5704–7276 kDa. Sulphate content varied from 0.175 ± 0.082% to 6.197 ± 0.446% across treatments. The agar also supported microbial growth at lower concentrations than commercial agar, indicating promising application potential. These findings highlight G. micropterum as a promising, sustainable option for expanding agar resources. Full article

Background an Objectives: The Mediterranean sea urchins Paracentrotus lividus and Arbacia lixula co-occur on shallow rocky reefs but display contrasting ecological and physiological traits. We compared their gonadal metabolomes to identify species-specific metabolic strategies. Methods: High-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy to intact gonadal tissues, combining multivariate chemometric modelling with targeted integration, boxplot-based univariate analysis and pathway analysis. Results:A. lixula showed an osmolyte- and redox-oriented phenotype with elevated betaine, taurine, sarcosine, trimethylamine (TMA), trimethylamine N-oxide (TMAO), carnitine, creatine, malonate, methylmalonate, uridine and xanthine. In contrast, P. lividus exhibited an amino-acid-enriched anabolic profile dominated by lysine, glycine and glutamine, together with higher levels of formaldehyde, methanol and 3-carboxypropyl-trimethylammonium. Pathway analysis indicated that A. lixula metabolites mapped onto glycine/serine–threonine metabolism and the folate-linked one-carbon pool, whereas P. lividus metabolites were enriched in glyoxylate/dicarboxylate, nitrogen and amino-acid pathways. These contrasting osmolyte–C₁ versus nitrogen–amino-acid strategies are compatible with species-specific host–microbiota metabolic interactions inferred from published microbiome data. Conclusions: Overall, our results support a framework in which A. lixula adopts a resilience-oriented osmolyte strategy and P. lividus an efficiency-oriented anabolic strategy, highlighting HR-MAS NMR metabolomics as a powerful approach to investigate adaptive biochemical diversity in marine invertebrates. Full article

The multicomponent synthesis of a novel and highly symmetric polyheterocycle based on the pyrrolo[3,4-b]pyridin-5-one core incorporating the privileged tetrahydroisoquinoline moiety is described. The target compound was synthesized as an inseparable mixture of stereoisomers through a pseudo-repetitive Ugi–Zhu five-component reaction (PR-UZ-5CR) coupled to a double post-transformation sequence involving an intermolecular aza Diels–Alder cycloaddition, an intramolecular N-acylation, and a final tandem aromatization step. The product was prepared in 63% overall yield, and with an excellent atom economy of 85%, within a total reaction time of 85 min, and a temperature range from 25 to 65 °C. Structural elucidation and molecular mass confirmation were successfully achieved through NMR and FT-IR spectroscopy, and high-resolution mass spectrometry (HRMS), respectively. Full article

Background/Objectives: Acute pneumonia remains one of the leading causes of mortality worldwide. The pathogenesis of the disease is determined by the nature of the host immune response. The balance between effector and regulatory T cells (Treg) is critical, as it determines the severity of inflammation and the regenerative capacity of lung tissue. The development of new approaches to modulate the immune response using promising synthetic compounds opens up the possibility of targeted cytokine balance restoration of cytokine balance and Tregs functions This study investigated the effects of the newly synthesized complex of 1-(2-Ethoxypropyl)-4-(pent-1-yn-1-yl)piperidin-4-yl Propionate with β-Cyclodextrin (MXF-22), on the populations of CD4⁺, CD4⁺CD25⁺ and CD4⁺FoxP3⁺ T cells in an oleic acid-induced acute lung injury rat model. Methods: Quantitative analysis of CD4⁺, CD4⁺CD25⁺, and CD4⁺FoxP3⁺ T cell subsets and serum IL-4 and TGF-β levels were determined by flow cytometry and ELISA assays, respectively. Results: The study revealed a significant decrease in the number of CD4⁺ T cells and their regulatory subsets (CD4⁺CD25⁺, CD4⁺FoxP3⁺) during acute pneumonia. Oral administration of MXF-22 contributed to a pronounced recovery of these parameters, accompanied by increased levels of IL-4 and TGF-β, which indicated the activation of anti-inflammatory and reparative processes. Conclusions: MXF-22 showed a pronounced immunomodulatory effect contributing to the restoration of the function of CD4⁺ FoxP3⁺ T regs in acute pneumonia rat model. Full article

This research constitutes a novel experimental approach to valorizing an industrial by-product: the ‘brick’. Studies put emphasis on the importance of detailed structural characterization of brickminerals and their chemical evolution upon heating, contributing rationally to the design and development of new glass–ceramic forms that would be suitable for efficiently encapsulating radio-nuclides. The brick used is a complex material composed of metakaolinite, illite, sand and impurities such as rutile and iron oxides/hydroxides. Raw brick was first activated with a range of sodium hydroxide concentrations, and, second, cured at different temperatures from 90 °C to 1200 °C. Alkali-brick frameworks gradually decomposed during the firing, and turned into crystalline ceramic phases (analcime and leucite) embedded inside an amorphous silica-rich phase. After each heating stage, the cured-brick sample was exhaustively characterized by using a variety of advanced analytical techniques, including powder X-ray diffraction, ESEM/EDS microscopy and ²⁹Si-²⁷Al-MAS-NMR spectroscopy. Ultra-high magnetic field NMR (28.2 T) was used to distinguish and quantify Al(IV), Al(V) and Al(VI) configurations, and to better follow distinctive changes in ²⁷Al environments of brickminerals under thermal effects. Glass-ceramized brick exhibited high specific density (~2.6 g·cm⁻³), high compactness and good corrosion resistance under static, mild and aggressive conditions, attesting to its high solidification and chemical durability. Full article

Substituted thiourea derivatives represent a structurally diverse group of compounds with high biological activity. In this paper, we present the synthesis of N-(9-ethyl-9H-carbazol-2-yl)-N′-(1-phenylethyl)thiourea by condensation reaction. The structure of the title compound was confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and high-resolution mass spectrometry (HRMS). Full article

A series of dimethylpyridine-3-carboxamide derivatives was designed as potential, selective, non-zinc chelating inhibitors of matrix metalloproteinase 13 (MMP-13), and subsequently synthesized. The identity of the obtained compounds was confirmed by FT-IR, ¹H/¹³C NMR, and HR-MS methods. Fluorescence spectroscopy was applied to study the interaction of synthesized compounds with human serum albumin, providing insight into their potential transport properties in plasma. In parallel, the electronic properties and reactivity parameters relevant to enzyme binding of the designed molecules were analyzed using density functional theory. Molecular docking and molecular dynamics simulations revealed the compounds to interact preferentially and stably within the S₁ pocket of MMP-13 via hydrogen bonds and π-stacking interactions. The calculated binding free energy confirmed the stability and persistence of the complexes during simulation, indicating a strong and specific recognition pattern. On the other hand, their affinity towards MMP-8 was considerably weaker, which is consistent with the predicted selectivity profile. In addition, the biological evaluation confirmed MMP-13 inhibition. Finally, in vitro tests revealed their cytotoxic activity against cancer cell lines. Full article

High production costs and sustainability issues are the main factors limiting the widespread application of carbon fibers in various industrial sectors. Lignin, a by-product from the paper and pulping industry, due to its high carbon content of up to 60%, can be considered a potential replacement for polyacrylonitrile in carbon fiber production. The production of lignins with distinct molecular weight distributions as well as group functionalities is essential to enhance high-value applications of lignin. In this study, we present a simple, green solvent-based fractionation method for LignoBoost softwood kraft lignin to obtain a lignin fraction with tailored physicochemical properties for electrospun carbon fiber production without polymeric spinning additives. Sequential solvent extraction was used to produce two fractions with distinct molecular weights: low-molecular-weight softwood kraft lignin (LMW-SKL) and high-molecular-weight softwood kraft lignin (HMW-SKL). The lignin fractions were characterized using size exclusion chromatography (SEC) for the molar mass distribution. The thermal properties of lignins were studied using thermogravimetry (TGA) and differential scanning calorimetry (DSC). Hydroxyl group content was quantified using quantitative ³¹P NMR spectroscopy. We successfully demonstrated the electrospinning of a high-molecular-weight lignin fraction—obtained in high yield from the fractionation process—without the use of any additives, followed by thermal conversion to produce electrospun carbon fibers. The presented results contribute to the valorization of lignin as well as to the development of green and sustainable technologies. Full article

The first representative of the aziridine-fused benzo[e][1,4]thiazine series was synthesized from methyl 2-bromo-2-phenyl-2H-azirine-2-carboxylate and benzo[d]thiazole in 74% yield. The reaction proceeds via the S_N2′-S_N2′-cascade to form the azirinylthiazolium salt followed by a water-induced thiazole ring expansion. The structure of the title compound was established based on ¹H, ¹³C, 2D NMR spectroscopy and high-resolution mass spectrometry, and unambiguously confirmed by X-ray diffraction analysis. Full article

One of the approaches to increase bioavailability and stability of hydrophobic biologically active compounds is their incorporation into polymer backbone. This work deals with the modification of chitosan (CS) with gossypol (GS), a phenolic compound with confirmed anticancer properties, by the free-radical grafting method. The series of the CS derivatives with increasing content of GS were prepared using pure GS or gossypol acetate (GSA) and compared to the control CS (cCS). The starting CS, cCS, and GS-containing derivatives were characterized using Fourier-transform infrared (FTIR), Raman, and ¹³C ssNMR spectroscopies; elemental and thermogravimetric analysis to evaluate the influence of the radicals and GS on the properties of polymers was performed. The Folin–Ciocalteu (F-C) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods were used to evaluate antioxidant properties of GS-modified CSs. Additionally, the polymer solubility and the specific viscosity of the solutions were determined. The content of GS in polymers raised proportionally with increasing amount of GS added to the reaction mixture, thereby enhancing the ability to scavenge free radicals. The type of GS used (GS or GSA) in polymers affected the degree of CS crosslinking (higher for pure GS), polymer solubility (lower for pure GS), the amount of grafted GS (~20% higher for GSA), and antioxidant properties in favor of GSA. Full article

The synthesis, phase behavior and semiconductor properties of two novel organosilicon tetramers with dialkyl-substituted [1]benzothieno[3,2-b]benzothiophene (BTBT) moieties, D4-Und-BTBT-Hex and D4-Hex-BTBT-Oct, are described. The synthesis of these molecules was carried out by sequential modification of the BTBT core by carbonyl-containing functional alkyl substituents using the Friedel–Crafts reaction, followed by the reduction in the keto group. The target tetramers, D4-Und-BTBT-Hex and D4-Hex-BTBT-Oct, were obtained by the hydrosilylation reaction between tetraallylsilane and corresponding 1,1,3,3-tetramethyl-1-(ω-(7-alkyl[1]benzothieno[3,2-b]benzothiophen-2-yl)alkyl)disiloxanes. The chemical structure of the compounds obtained was confirmed by NMR ¹H-, ¹³C- and ²⁹Si-spectroscopy, gel permeation chromatography and elemental analysis. Their phase behavior was investigated by differential scanning calorimetry, polarization optical microscopy and X-ray diffraction analysis. It was found that D4-Und-BTBT-Hex shows higher crystallinity at room temperature as compared to D4-Hex-BTBT-Oct, while both molecules possess smectic ordering favorable for active layer formation in organic field-effect transistors (OFETs). The active layers were applied by spin-coating under conditions of a homogeneous thin layer formation with a low content of defects. The devices obtained from D4-Und-BTBT-Hex have demonstrated good semiconductor characteristics in OFETs with a hole mobility up to 3.5 × 10⁻² cm² V⁻¹ s⁻¹, a low threshold voltage and an on/off ratio up to 10⁷. Full article

β–Cyclodextrin (β–CD)-based materials are widely used in drug delivery, yet their interactions with mucosal barriers remain insufficiently understood. Because the mucus layer coating epithelial surfaces can hinder drug transport, elucidating β–CD–mucin interactions is critical for optimizing cyclodextrin-based carriers. In this study, we examined whether PEGylation can attenuate the mucoadhesive behavior of β–CD. Monomethoxy poly(ethylene glycol)-modified β–CDs (MPEG–β–CDs) were evaluated using ¹⁹F self-diffusion NMR spectroscopy coupled with a kinetic diffusion model describing reversible binding to stationary substrates. Mucin hydrogels were prepared from bovine submaxillary mucin and served as a model mucus environment. Diffusion coefficients were extracted from the ¹⁹F NMR signals of 1-fluoroadamantane (1FA) molecules encapsulated within HP-β–CD or MPEG–β–CD cavities. The results demonstrate that PEGylation substantially reduces β–CD–mucin adhesion, with longer PEG chains (2000 Da) providing more effective steric shielding than shorter chains (500 Da). These findings indicate that PEGylation can protect β–CD-included drugs during transport across mucosal barriers by minimizing unwanted β–CD–mucin interactions. Full article