Search Results (3,121)

Sulfation of arabinogalactan (AG) from larch wood (Larix sibirica Ledeb.) in the melt of a sulfamic acid–urea mixture has been first examined. The impact of the AG sulfation temperature on the AG sulfate yield and the sulfur content has been established. The high sulfur content (11.3–11.6%) in sulfated AG has been obtained in the temperature range of 115–120 °C for a sulfation time of 0.5 h. The process effectively prevents molecular degradation under these conditions. The incorporation of sulfate groups into the arabinogalactan structure has been confirmed by the appearance of absorption bands in the FTIR spectrum that are typical of sulfate group vibrations. The ¹³C NMR spectroscopy study has proven that the AG sulfation in the melt of a sulfamic acid–urea mixture leads to the substitution of some free hydroxyl groups for C6, C4, and C2 carbon atoms of the AG β-D-galactopyranose units. The advantage of the proposed AG sulfation method is that the reaction occurs without solvent, and the reaction time is only 0.5 h. The kinetics of the thermal decomposition of the initial AG and sulfated AG samples have been studied. It has been found that the sulfated AG samples have a lower thermal resistance than the initial AG. The kinetic analysis has revealed a decrease in the activation energy of the thermal degradation of the sulfated samples as compared to the initial AG. Full article

In this study, self-healing hydrogels were created using oxidized hydroxybutanoyl glycan (OHbG) and quaternized carboxymethyl chitosan (QCMCS), displaying antioxidant and antibacterial properties for pH-responsive drug delivery. The structures of the modified polysaccharides were confirmed through ¹H NMR analysis. Double crosslinking in the hydrogel occurred via imine bonds (between the aldehyde group of OHbG and the amine group of QCMCS) and ionic interactions (between the carboxyl group of OHbG and the quaternized group of QCMCS). The hydrogel exhibited self-healing properties and improved thermal stability with an increase in OHbG concentration. The OHbG/QCMCS hydrogel demonstrated high compressive strength, significant swelling, and large pore size. Drug release profiles varied between pH 2.0 (96.57%) and pH 7.4 (63.22%). Additionally, the hydrogel displayed antioxidant and antibacterial effects without compromising the polysaccharides’ inherent characteristics. No cytotoxicity was observed in any hydrogel samples. These findings indicate that the OHbG/QCMCS hydrogel is a biocompatible and stimuli-responsive drug carrier, with potential for various pharmaceutical, biomedical, and biotechnological applications. Full article

Pinnatoxins, a group of marine biotoxins primarily produced by the dinoflagellate Vulcanodinium rugosum, have garnered significant attention due to their potent toxic effects and widespread distribution in marine ecosystems. LC–MS analysis of shellfish and V. rugosum cultures revealed the presence of previously unidentified isomers of pinnatoxins D, E, F, and H, at levels approximately six times lower than those of known isomers. The chemical structures of these isopinnatoxins were determined using a combination of LC–MS/MS and NMR spectroscopy, which demonstrated that the isomerization of each pinnatoxin occurred through the opening and recyclization of the spiro-linked tetrahydropyranyl D-ring to form a smaller tetrahydrofuranyl ring. The acute toxicity of isopinnatoxin E was determined by intraperitoneal injection into mice and was found to be significantly lower than that of pinnatoxin E. Given their low toxicity and low abundance, it is unlikely that isopinnatoxins contribute significantly to the overall toxicity of pinnatoxins. Full article

In this work, we describe the synthesis of three new meso-arylporphyrins, named meso-tetrakis [4-(nicotinoyloxy)phenyl] porphyrin (H₂TNPP), meso-tetrakis [4-(picolinoyloxy)phenyl] porphyrin (H₂TPPP), and meso-tetrakis [4-(isonicotinoyloxy) phenyl] porphyrin (H₂TIPP). These new synthesized meso-arylporphyrins are characterized using spectroscopic analysis: Fourier Transform Infrared Spectroscopy (FTIR) and One-dimensional Nuclear Magnetic Resonance (1D NMR), and mass spectrometry (MS). The photophysical studies (UV–visible absorption, singlet oxygen (¹O₂) luminescence, and fluorescence emissions) demonstrate their potential uses as photosensitizers (PSs) in photodynamic therapy (PDT) applications. An in vitro investigation of the anti-fungal activity of H₂TNPP, H₂TPPP, and H₂TIPP against Candida (C.) species (C. albicans, C. glabrata, and C. tropicalis) reveals that their minimum inhibitory concentration (MIC) values ranged from 1.25 to 5 mg/mL. In addition, their in vitro anti-fungal susceptibilities against three dermatophyte clinical isolates (Trichophyton rubrum, Microsporum canis, and Trichophyton mentagrophytes) are also evaluated and they demonstrate good anti-fungal activities. A molecular docking study of these meso-arylporphyrins as anti-fungal agents against C. tropicalis extracellular aspartic proteinases, Protein data Bank in Europe (PDBe code: 1J71) and Trichophyton rubrum Sialidases (PDBe code: 7P1D) underlines the possible interactions of H₂TNPP, H₂TPPP, and H₂TIPP with the key amino acid residues of these fungal target proteins. Full article

This study investigates the electrochemical oxidation mechanisms of chlorpromazine (CPZ), revealing a novel three-electron oxidation pathway that challenges the traditionally accepted two-electron paradigm, offering new insights into CPZ oxidation pathways. Using an integrated approach combining cyclic voltammetry, bulk electrolysis, UV-Vis, FT-IR, ¹H-NMR spectroscopy, and LC-MS/MS analysis, we demonstrate that CPZ undergoes sequential oxidation processes involving both the phenothiazine core and the tertiary amine-containing side chain. Our results highlight the critical role of side-chain oxidation in forming nor-CPZ sulfoxide, an often-overlooked metabolite, which may influence CPZ’s metabolic and pharmacological behaviour. Spectroelectrochemical data reveal stable intermediate species, providing insight into the structural rearrangements accompanying oxidation. This work offers a detailed mechanistic understanding of CPZ redox behaviour, contributing to improved interpretations of its pharmacological and metabolic properties. Full article

Aflatoxin B1 (AFB1), a highly toxic secondary metabolite produced by Aspergillus species, represents a significant health hazard due to its widespread contamination of agricultural products. The urgent need for sensitive and sustainable detection methods has driven the development of diverse analytical approaches, most of which heavily rely on organic solvents, posing environmental challenges for routine food safety analysis. Here, we introduce a supramolecular platform leveraging acyclic cucurbit[n]uril (acCB) as a host molecule for environmentally sustainable AFB1 detection. Screening various acCB derivatives identified acCB6 as a superior host capable of forming a stable 1:1 complex with AFB1 in an aqueous solution, exhibiting a high binding affinity. Proton nuclear magnetic resonance (1H NMR) spectroscopy confirmed that AFB1 was deeply encapsulated within the host cavity, with isothermal titration calorimetry (ITC) experiments and molecular dynamics simulations further substantiating the stability of the interaction, driven by enthalpic and entropic contributions. This supramolecular host was incorporated into a scaffold-assembly-based bioluminescent enzyme immunoassay (SA-BLEIA), providing a green detection platform that rivals the performance of traditional organic solvent-based assays. Our findings highlight the potential of supramolecular chemistry as a foundation for eco-friendly mycotoxin detection and offer valuable insights into designing environmentally sustainable analytical methods. Full article

Backgrounds: This study explores the design of substituted tetrahydroquinoline (THQ) derivatives and their synthesis as possible inhibitors of mTOR inhibitors for targeted cancer therapy. Methods: Inspired by the structural characteristics of known mTOR inhibitors, eight novel derivatives were synthesized, characterized using mass spectroscopy, ¹H, and ¹³C NMR, and evaluated for anticancer activity. Results: Computational studies, including molecular docking and molecular dynamics (MD) simulations, highlighted the derivative’s strong binding interaction and stability within the mTOR active site. Assays for in vitro cytotoxicity showed strong and specific anticancer action against cell lines of triple-negative breast cancer, lung cancer, and breast cancer while causing negligible impact on healthy cells. Conclusions: Compound 10e emerged as the most promising candidate, displaying exceptional activity against A549 cells (IC₅₀ = 0.033 µM) and inducing apoptosis in a dose-dependent manner, surpassing standard agents, like Everolimus and 5-flurouracil. Structure–activity relationship analysis revealed that incorporating trifluoromethyl and morpholine moieties significantly enhanced selectivity and potency. MD simulations further validated these findings, confirming stable protein-ligand interactions and favorable dynamics over a 100-ns simulation period. Collectively, this study underscores the therapeutic potential of THQ derivatives, particularly compound 10e, as promising mTOR inhibitors with potential applications in lung cancer treatment. Full article

Background/Objectives: Neglected tropical diseases (NTDs), such as leishmaniasis, remain a global health challenge due to limited therapeutic options and rising drug resistance. In this study, we developed an advanced nanogel formulation incorporating curcumin (CUR) and Pectis brevipedunculata essential oil (EOPb) within an F127/Carbopol 974P matrix to enhance bioavailability and therapeutic efficacy against Leishmania (Leishmania) amazonensis (LLa) promastigotes. Methods: The chemical profile of EOPb was determined through GC-MS and NMR analyses, confirming the presence of key bioactive monoterpenes such as neral, geranial, $\alpha$-pinene, and limonene. The nanogel formulation (nGPC) was optimized to ensure thermosensitivity, and stability, exhibiting a sol–gel transition at physiological temperatures. Rheological analysis revealed that nGPC exhibited Newtonian behavior at 5 °C, transitioning to shear-thinning and thixotropic characteristics at 25 and 32 °C, respectively. This behavior facilitates its application and controlled drug release, making it ideal for topical formulations. Dynamic light scattering (DLS) analysis demonstrated that nGPC maintained a stable nanoscale structure with hydrodynamic radius below 300 nm, while Fourier-transform infrared spectroscopy (FTIR) confirmed strong molecular interactions between EOPb, CUR, and the polymer matrix. Biological assays demonstrated that nGPC significantly enhanced anti-promastigote activity compared to free CUR and OEPb. Results: At the highest tested concentration (50 μg/mL EOPb and 17.5 μg/mL CUR) nGPC induced over 88% mortality in LLa promastigotes across 24, 48, and 72 h, indicating sustained efficacy. Even at lower concentrations, nGPC retained dose-dependent activity, suggesting a synergistic effect between CUR and EOPb. These findings highlight the potential of nGPC as an innovative nanocarrier for daylight photodynamic therapy (dPDT) in the treatment of leishmaniasis. Future studies will investigate the underlying mechanisms of this synergism and explore the potential application of photodynamic therapy (PDT) to further enhance therapeutic outcomes. Full article

In this report, we discuss the synthesis of modified betulin through the chemical derivatization of a natural compound. The compound was fully characterized by proton (¹H), carbon-13 (¹³C), heteronuclear single quantum coherence (HSQC) and distortionless enhancement through polarization transfer (DEPT) NMR and elemental analysis. We investigated the optical properties through ultraviolet (UV) and Fourier-transform infrared (FTIR) spectroscopy. Full article

In this work, we report the observation of uncatalyzed ene reactions between several phenylpropanoid compounds and diethyl azodicarboxylate (DEAD). For allylbenzene, the reaction produces the ene product at molar ratios of up to 1:2 of allylbenzene to DEAD. At higher levels of DEAD, more complex reactions are observed. For the reaction between methyl eugenol and DEAD, similar ene reaction products have been found. However, the reaction of eugenol with DEAD is more complex; in addition to the ene reaction, other reactions happen at the same time. Most of the structures of the resulting products have been elucidated using NMR spectroscopy (¹H, ¹³C, and 2D), and the findings have been further corroborated by FTIR analysis. Interestingly, these products appear to undergo molecular aggregation, which results in self-thickening in their neat form. However, the viscosity significantly decreases upon dilution with a solvent. This self-thickening property suggests their potential use as thickening agents in organic solvent formulations. Full article

The plant kingdom serves as a valuable resource for cancer drug development. This study explored the antitumor activity of different sub-fractions (hexane, dichloromethane and methanol) of U. gallii (gorse) methanol extract in glioblastoma (U-87MG and U-373MG) and neuroblastoma (SH-SY5Y) cell lines, along with their phytochemical profiles. Cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, and cell cycle arrest and apoptosis were assessed through flow cytometry and by measuring reactive oxygen species (ROS) and protein expression levels. D7 and D8 dichloromethane sub-fractions significantly reduced cell viability, triggered early apoptosis in SH-SY5Y and U-87MG cells and specifically increased ROS levels in U-87MG cells. Western blot analyses showed that D7 increased p53, caspase-3, caspase-8 and γH2AX expression in SH-SY5Y and U-87MG cells, while D8 specifically elevated p53 in SH-SY5Y cells and caspase-3 in both cell lines. In U-373 cells, D7 and D8 markedly reduced cell viability, with D8 inducing necrosis. Morphological changes indicative of apoptosis were also observed in all cell lines. Bioinformatic analysis of UHPLC-MS and GC-MS data tentatively identified 20 metabolites in D7 and 15 in D8, primarily flavonoids. HPLC-DAD confirmed isoprunetin and genistein as the most abundant in D7 and D8, respectively, both isolated and identified by NMR spectroscopy. Most of the flavonoids identified have been reported as antitumor agents, suggesting that these compounds may be responsible for the observed pharmacological activity. Full article

A continuous flow process was optimised for the perchlorination of p-cresol to the corresponding 2,4,6-trichloro-cyclohexa-2,5-dienone derivative employing trichloroisocyanuric acid as a green and safer-to-handle chlorinating agent. The system could furnish 200 g of pure material within 5 h of operation (throughput = 40 g h⁻¹). The compound was easily isolated by filtration and obtained in 95% purity as determined by GC analysis; it could be further purified by crystallisation from a 20:1 Hexane/AcOEt mixture left at −20 °C overnight. The resultant product was characterised by ¹H & ¹³C NMR, MS, IR analyses, with melting point and X-ray single-crystal data being obtained, confirming the structure. Full article

The chemical profiles of young and mature wines produced from three grape varieties Merlot, Mavrud, and Sauvignon blanc were analyzed using ¹H nuclear magnetic resonance (NMR) spectroscopy and advanced statistical methods. Furthermore, grape ales―a hybrid of beer and wine—were subjected to analysis to facilitate a comparison of their composition with that of traditional wines. The analysis yielded a total of 37 compounds, which were identified and quantified. Orthogonal partial least squares discriminant analysis (OPLS-DA) models were employed to distinguish the chemical profiles of young and mature wines, as well as those of grape ales. The findings demonstrate that the fermentation and aging processes result in the formation of distinctive chemical signatures in wines, with key compounds such as shikimic acid and fructose contributing to this differentiation. The identified compounds comprise seven alcohols (2,3-butanediol, glycerol, 2-methylpropan-1-ol, 3-methyl-butan-1-ol, myo-inositol, 1-propanol, 2-phenylethanol), six organic acids (galacturonic, citric, lactic, malic, shikimic, succinic), three amino acids (alanine, proline, tyrosine), four sugars (arabinose, fructose, galactose, glucose), coutaric acid, and acetoin. The levels of these 22 components enabled the successful differentiation of young and mature wines among the three grape varieties. These findings underscore the substantial chemical distinctions between grape ales and wines, thereby emphasizing the potential of grape ales as an innovative fermented beverage. Full article

Introduction: Serum metabolome changes after acute ischemic stroke (AIS), but the significance of this is poorly understood. We evaluated whether this change is associated with AIS outcomes in patients with large vessel occlusion (LVO). To improve validity, we combined cross-sectional and longitudinal designs and analyzed serum using Nuclear Magnetic Resonance (NMR) and Liquid Chromatography–Mass Spectrometry (LC-MS). Methodology: In the cross-sectional part, we compared serum metabolome from 48 LVO strokes, collected at 48–72 h, and analyzed with NMR, while in the longitudinal part, we compared metabolome from 15 LVO strokes, collected at <24 h, 48–72 h, 5–7 days, and 80–120 days, and analyzed with LC-MS between patients with modified Rankin Scores (mRS) of 0–3 and 4–6 at 90 days. We hypothesized that compounds elevated in patients with mRS 0–3 in the cross-sectional part would also be elevated in the longitudinal part, and vice versa. We used regression for the analysis and TSBH for multiple testing. Results: In the cross-sectional part, cholesterol, choline, phosphoglycerides, sphingomyelins, and phosphatidylethanolamines had lower levels in patients with an mRS of 0–3 compared to an mRS of 4–6. In the longitudinal part, lower levels of sphingomyelin (d18:1/19:0, d19:1/18:0)* significantly correlated with an mRS of 0–3 in patients with small infarction volume, while lower levels of sphingolipid N-palmitoyl-sphingosine (d18:1/16:0), 1-palmitoyl-2-docosahexaenoyl-GPC (16:0/22:6), 1-palmitoyl-2-docosahexaenoyl-GPE, palmitoyl-docosahexaenoyl-glycerol (16:0/22:6), campesterol, and 3beta-hydroxy-5-cholestenoate correlated with an mRS of 0–3 in patients with large infarction volume. Conclusions: This pilot study showed that lower levels of lipidomic components nerve cell membrane correlate with good AIS outcomes. If proven on large-scale studies, these compounds may become important AIS outcome markers. Full article

The ‘wire-like’ acetylenic moiety is an important building block in organic and coordination chemistry that can facilitate electron transfer in donor–acceptor compounds, contributing to the enhancement of their photophysical properties. 2,6-Bis-(thiazol-2-yl)pyridine (dtpy) functionalized with a 4-phenylacetylene group (Ph-C≡C-dtpy) was, for the first time, used for the preparation of [ReCl(CO)₃(Ph-C≡C-dtpy)] and [Pt(Ph-C≡C-dtpy)Cl]CF₃SO₃ in order to understand the properties derived from the use of the acetylenic substituent. The coordination ability of Ph-C≡C-dtpy toward Pt(II) and Re(I) centers was determined. All the studied compounds were characterized using FT-IR, ¹H NMR, and ¹³C NMR spectroscopies, elemental analysis and, in the case of the free ligand and rhenium(I) complex, single-crystal X-ray analysis was also used. Their electrochemical, photophysical, and thermal properties were compared with the previously described similar systems. The photoluminescence spectra of Ph-C≡C-dtpy, [ReCl(CO)₃(Ph-C≡C-dtpy)] and [Pt(Ph-C≡C-dtpy)Cl]CF₃SO₃ were investigated in solution and in the solid state at 298 K and 77 K. The experimental results were supported by the DFT and TD-DFT calculations. As a result of the introduction of the -C≡C- moiety into the organic ligand skeleton, the Re(I) and Pt(II) complexes display room-temperature emission. In the case of [Pt(Ph-C≡C-dtpy)Cl]CF₃SO₃, photoluminescence lifetime in a microsecond regime was observed, whereas nanosecond lifetime for [ReCl(CO)₃(Ph-C≡C-dtpy)] in solution is comparable to lifetimes previously observed for rhenium(I) compounds with 4-substituted dtpys. Full article