BMC Chemistry最新文献

A novel green spectrofluorometric method was developed for the quantification of diltiazem hydrochloride (DLZ), a benzothiazepine-class calcium channel blocker with vasodilatory properties. The assay exploits the rapid fluorescence quenching of Acid Red 87—a fluorone-based dye—upon complexation with DLZ in acidic medium (pH 3.8). This “on-off” mechanism enables selective DLZ detection by measuring the decrease in Acid Red 87 native fluorescence intensity (λ_ex/λ_em = 302.5/545.8 nm). Key parameters (pH, dye concentration, buffer volume) were systematically optimized, yielding a linear response over 50–1100 ng/mL (r² = 0.9991) with a detection limit of 15.5 ng/mL. The method was rigorously validated per ICH Q2(R1) guidelines, confirming precision (RSD < 2%), accuracy (99.76% % recovery), and robustness. It was successfully applied to analyze DLZ in pharmaceutical formulations (tablets/capsules) with no matrix interference, and the statistical comparison (t- and F-tests) showed no significant difference from the reference method. Critically, the procedure uses distilled water as the sole solvent, aligning with green chemistry principles while offering simplicity, cost-efficiency, and high-throughput potential.

The present study explores, for the first time, the physicochemical and molecular interaction behaviour of tetramethylammonium hydroxide (TMAH)–caffeine (CAF) mixtures in aqueous medium. Caffeine (CAF) is a widely consumed central nervous system stimulant, and tetramethylammonium hydroxide (TMAH) is an industrially significant compound with known toxicological implications. Combination of these two solutes represents a novel system where ionic, hydrophobic, and hydrogen-bonding interactions coexist, providing unique insight into mixed solute behaviour and solvation dynamics in aqueous media. This work focuses on the physicochemical, acoustic and thermodynamic properties of aqueous TMAH solutions in the presence of varying concentrations of CAF over a range of temperatures (293.15–313.15 K). Acoustic measurements, including ultrasonic velocity, and density were utilized to compute key thermodynamic parameters such as compressibility, relaxation strength, specific heat capacity, acoustic impedance, internal pressure, and isobaric expansion coefficient. The results reveal complex ion–solvent and ion–cosolute interactions, highlighting significant structural reorganization within the solution matrix. Observations such as decreasing compressibility and relaxation strength with concentration and temperature suggest stronger intermolecular forces, while variations in partial molar compressibility and transfer parameters indicate hydration shell modification due to CAF’s presence. The findings offer valuable insights into hydration dynamics and solvation behaviour, with practical relevance to drug delivery, material design, and toxicity evaluation. This work advances understanding of solute–cosolute interactions, supporting applications in pharmaceutical formulations and chemical process development.

Graphical abstract

This study presents an ultrasensitive electrochemical sensor aimed at the detection and quantification of ertugliflozin l-pyroglutamic acid (EGZ), an anti-diabetic agent, using molecularly imprinted polymer (MIP) technology. The sensor was fabricated by electropolymerizing o-phenylenediamine (o-PD) onto a pencil graphite electrode (PGE), with EGZ serving as the template molecule. The detection of EGZ was achieved through indirect sensing, where EGZ competes with the redox-active probe ferrocyanide/ferricyanide ([Fe (CN)₆]^3−/4−) for the binding sites of the MIP. The resulting electrical signal was measured using differential pulse voltammetry (DPV). The sensor demonstrated excellent sensitivity, with a linear response range from 1 × 10⁻¹² to 1 × 10⁻¹⁰ M and a limit of detection (LOD) of 6.3 × 10⁻¹⁴ M. A non-imprinted polymer (NIP) was prepared under the same electropolymerization conditions but without the inclusion of EGZ. The NIP sensor served as a control, and the imprinting factor (IF) was determined to be 6, confirming the success of the imprinting process and the formation of selective recognition sites. Characterization of the proposed sensor was conducted using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis (EDX). Additionally, the sensor successfully detected EGZ in spiked human plasma, demonstrating its practical applicability in complex biological samples. The environmental impact of the proposed method was assessed using the AGREE and GAPI green evaluation tools, which confirmed its environmentally friendly nature. Furthermore, the sensor exhibited high selectivity in the presence of commonly co-formulated drugs, such as sitagliptin and metformin, indicating its potential for pharmaceutical applications.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (NP) interaction with viral RNA is vital for viral replication and immune evasion, making it an attractive target for antiviral development. Inspired by adenosine triphosphate (ATP)’s competitive inhibition of NP–RNA binding, we screened 121 FDA-approved ATP-competitive kinase inhibitors, identifying mitoxantrone (IC₅₀ = 1.22 µM) as a potent inhibitor. Considering its known topoisomerase inhibitory activity, we further screened 23 additional topoisomerase inhibitors, uncovering four active compounds—pixantrone (IC₅₀ = 5.67 µM), doxorubicin (IC₅₀ = 20.19 µM), epirubicin (IC₅₀ = 7.23 µM), and suramin (IC₅₀ = 0.44 µM). Biolayer interferometry (BLI) revealed distinct inhibition mechanisms: suramin bound directly to the NP C-terminal domain (CTD) with a K_D of 0.26 µM, whereas the other compounds primarily targeted RNA, with pixantrone showing the highest RNA affinity (K_D = 0.63 µM). Complementary molecular docking analyses supported these observations, indicating suramin’s preference for NP binding and anthracycline derivatives engaging RNA. Our findings demonstrate the feasibility of a mechanism-informed repurposing strategy and identify FDA-approved topoisomerase inhibitors and suramin as valuable chemical starting points. Although these compounds are not directly suitable as antivirals due to toxicity concerns, they provide promising scaffolds for further optimization aimed at selective disruption of SARS-CoV-2 NP–RNA interactions.

1,3,4-Oxadiazoles are a vital class of heterocyclic compounds known for their diverse biological activities. In this study, a series of eight novel 1,3,4-oxadiazolyl sulfide derivatives 4a–h were synthesized and characterized using IR, NMR, and elemental analysis. The antioxidant activity of these derivatives was evaluated via DPPH and ABTS assays, revealing promising radical scavenging capabilities Compound 4 h emerged as the most potent antioxidant with SC₅₀ values of 9.88 µM (ABTS) and 12.34 µM (DPPH), outperforming standard antioxidants surpassing standard antioxidants such as ascorbic acid (SC₅₀ = 23.92 µM) and gallic acid (SC₅₀ = 21.24 µM). The impact of electron-donating and electron-withdrawing substituents on activity was demonstrated through a comprehensive structure-activity relationship (SAR) study. Molecular docking against α-glucosidase (PDB: 3W37) validated the potential of these compounds as enzyme inhibitors, with docking scores ranging from − 8.59 to -9.81 kcal/mol and similar modes of binding. Insights into electronic properties were obtained through density functional theory (DFT) calculations, emphasizing that compound with the lowest HOMO–LUMO energy gaps (4b) exhibited higher polarizability and enhanced reactivity, which correlates with their biological antioxidant performance. This integrated study underscores the therapeutic potential of these derivatives as antioxidants and enzyme inhibitors, offering paths for further drug development.

Glass fiber is an inorganic reinforcement material widely used in rubber-based technological products. This study investigates the properties of natural rubber/glass fiber composites, focusing on their potential to enhance mechanical performance while reducing costs. A series of tests were conducted to evaluate the rheological, mechanical, swelling, and morphological characteristics of the investigated natural rubber composites. Quantitative analysis showed that the composition containing 16 phr glass fiber resulted in a 59.5% increase in tensile strength compared to composites filled with traditional fillers such as sodium bentonite, calcium carbonate, silica, and calcined kaolin. The composite also showed a significant boost in mechanical properties, with notable increases in modulus at 100% and 300% strain, strain energy, and a stronger Payne effect, which indicates strong interfacial adhesion, as confirmed by morphological analysis. Morphological analysis of fractured surfaces confirmed excellent adhesion between glass fiber and natural rubber. Notably, the natural rubber/16 phr glass fiber composite exhibited exceptional swelling resistance in toluene, with a quantifiable reduction in swelling compared to other composites. This makes it suitable for automotive interiors. Cytotoxicity tests verified that the material is non-toxic, supporting its use in human-related applications. These results suggest that glass fiber is a better and more sustainable reinforcing filler for enhancing the performance of rubber products in the automotive industry.

Graphical Abstract

Objectives

The study aimed to explore novel aromatic ether coumarins as potential anti-allergic lead compounds.

Methods

The benzene ring of hypervalent iodine compounds was strategically introduced into the coumarin framework to facilitate the efficient synthesis of aromatic ether coumarin derivatives via the one-pot method. Two representative compounds, namely, 4-phenylether coumarin and 7-phenylether coumarin, were successfully designed and synthesized. The compounds were structurally characterized using spectroscopic techniques, including nuclear magnetic resonance (NMR), mass spectrometry (MS), and infrared (IR) spectroscopy. Their inhibitory effects on both IgE- and non-IgE-mediated degranulation of rat basophilic leukemia (RBL-2H3) cells and mouse bone marrow derived mast cells (BMMCs) were subsequently evaluated.

Results

Three representative 7-phenylether coumarins (4, 5, and 6) and 4-phenylether coumarin (7) were synthesized with high efficiency. The compounds exhibited potent anti-allergic effects, indicated by the marked inhibition of degranulation and β-HEX release from RBL-2H3 cells and BMMCs. The inhibitory effects of 7-phenylether 3-methyl ketocoumarin (6) were found to be superior to those of the tested compounds.

Conclusion

Aromatic ether coumarins can be efficiently constructed via the oxidation of hydroxycoumarins with hypervalent iodine compounds. Compound 6 inhibited both IgE-induced and calcium ionophore (A23187)-mediated degranulation of BMMCs, warranting further in-depth investigation into its pharmacogenetic and therapeutic potential.

The extensive use of antibiotics and their persistence in the environment make them emerging pollutants of global concern, posing serious risks to ecosystems and public health. Among them, the broad-spectrum fluoroquinolone antibiotic levofloxacin (LEV) is widely prescribed for bacterial infections and has frequently been detected in freshwater systems and environmental matrices. Its presence is linked to the development of antibiotic resistance and ecological toxicity, underscoring the urgent need for efficient removal strategies. In this study, levofloxacin-imprinted polymers (LEV-MIPs) were developed using a precipitation polymerisation method. A set of nine LEV-MIPs was synthesised using three solvent combinations: ethanol: acetonitrile, ethanol: dimethyl sulfoxide, and ethanol: carbon tetrachloride. Methacrylic acid (MAA) served as the functional monomer (1–3 mmol), ethylene glycol dimethacrylate (EGDMA) as the cross-linker (16 mmol), and azobisisobutyronitrile (AIBN) as the initiator (0.1 mmol). Among them, two formulations (LEV3-MIP and LEV6-MIP) demonstrated superior removal efficiency. Structural and thermal characterisation by FTIR, SEM/EDX, and TGA confirmed successful polymer synthesis, with surface analysis revealing spherical, monodispersed particles of ~ 1.5 μm. Batch adsorption assays showed removal efficiencies of 97.85% (LEV3-MIP) and 99.15% (LEV6-MIP) under optimised conditions (15 ppm initial concentration, 0.3 mg dosage, pH 7, and 90 min and 60 min contact time, respectively). Both polymers exhibited high imprinting factors (3.081 and 3.359) and excellent reusability, with minimal efficiency loss of only 2.7% and 2.09% after ten adsorption–desorption cycles. These results highlight the strong potential of LEV-MIPs as cost-effective, selective, and reusable materials for mitigating antibiotic pollution.

In this study, a range of photocatalysts, including zinc and cerium oxides, were developed using the precipitation technique, while impregnation was used to produce multiwalled CNTs with zinc oxide, multiwalled CNTs with zinc oxide/cerium oxides, and zeolite-based multiwalled CNTs with zinc oxide/cerium oxides. Advanced instruments, such as XRD, UV-Vis, and photoluminescence (PL) devices, were used to analyze the crystal structure, bandgap, and optical properties of each photocatalyst. Methylene blue, an organic contaminant, and sewage from Ethiopia’s Bahir Dar cloth industry were used to assess the photocatalytic efficacy of both assisted and unassisted nanocomposites. Under visible light irradiation, the TZ (zeolite with MWCNTs/ZnO/CeO₂) demonstrated a higher degradation performance of MB dye than the T3 nanocomposite, attaining 93.71% and 83.21%, respectively. This implies that by increasing the adsorption capacity, zeolite greatly improves the composite’s performance. The stability of the TZ in photocatalytic degradation was assessed, showing a 20.8% reduction after four consecutive runs, confirming the nanocomposite’s good stability. Furthermore, the mentioned photocatalyst (TZ) demonstrated greater performance in the degradation of MB with approximately 94.12% compared to the sewage sample efficiency of 76.75%.

Ionic liquids (ILs) have gained significant attention among material scientists for their versatile properties. Amino acid-based ionic liquids (AAILs) have the potential to be tailored for desired physicochemical properties due to their structural adaptability and unique attributes. Twenty-four distinct ILs were synthesized, containing multifunctional cations viz. 1-octyl pyridinium, 1-octyl-3-methylimidazolium, 1,3-dioctylimidazolium, Di-octyldi-butylammonium, Tetraoctylphosphonium, N, N, N', N'-Tetrakis-(2-hydroxyethyl)dioctyldiammonium, 1H-1,2,3-triazole, and 1-octyl-1,8-diazabicyclo(5.4.0)undec-7-enium, each with varied chain lengths. Whereas, bromide, glycinate, and leucinate were incorporated as counter-anionic species. These distinct ILs were characterized by FT-IR, ¹H, and ¹³C-NMR spectroscopies and were systematically evaluated for anti-bacterial efficacy by agar well diffusion method against six potent bacterial strains. Both gram-positive as well as gram-negative types, namely Shigella dysenteria, Shigella boyydii, Staphylococcus aureus, Carbapenem-resistant Enterobacter baumannii, Escherichia coli, and Klebsiella pneumonia were tested. Remarkably strong antibacterial performance was observed across most of the synthesized ILs, particularly notable against gram-negative strains, signifying their potential as antibacterial agents. The good antibacterial performance of ILs was also validated by molecular docking, and a good agreement was found between computational and experimental studies. These findings open new avenues for the development of effective antibacterial agents based on ILs in infection control for individuals with disabilities.