BMC Chemistry最新文献

α-Tocopherol (α-TQ) is a potent antioxidant with diverse applications in the food and pharmaceutical industries. It is susceptible to oxidation by various reactive oxygen species (ROS). This study first identifies the oxidation product of α-tocopherol produced by either H₂O₂ or HOCl, which could be formed in foods and biological systems. Second, the kinetic and mechanistic aspects of these oxidation reactions are characterized. Finally, the anticancer activity of α-TQ and its oxidation products was revealed. The direct oxidation product is α-tocopheryl quinone (α-TQQ), which dimerizes through an ether linkage and undergoes addition reactions. LC-MS/MS identified new products, primarily including positional and diastereoisomers of α-TQQ dimers resulting from H₂O₂ and HOCl addition. A kinetic study demonstrated that the oxidation reaction is first-order for both α-TQ and H₂O₂ or HOCl. The mechanism is proposed based on the identified products and kinetic behavior. The postulated mechanism also aligns with the reaction’s UV-Vis spectra, including the formation of the hemiketal (242 nm) and α-TQQ (261 nm) intermediates, as well as the addition products of the α-TQQ dimer (265 nm). α-TQQ dimer products of H₂O₂ oxidation reaction exhibited 1.7-fold (IC50 264.72 µM) and 2.0-fold (IC50 253.72 µM) higher cytotoxicity than that of α-TQ (IC50 448.45 and 496.53 µM) against breast (MCF-7) and prostate (PC-3) cancer cells, respectively. These results indicate that natural α-TQ and its oxidation products, when administered at a suitable dose, can express protection against various types of cancer.

Graphical abstract

This study reports the development of a novel, low-cost, and highly sensitive sensor for the rapid and efficient electrochemical detection of trace amounts of the antibiotic Linezolid (LNZO) in both synthetic solutions and real samples. The proposed sensor is based on a carbon paste electrode (CPE) modified with calcium oxide nanoparticles (CaO-NPs) and further enhanced through electropolymerization of D-alanine (PoDA). Eggshell waste was recycled as a low-cost and eco-friendly source of calcium oxide nanoparticles (CaO-NPs). The synergistic effect of CaO-NPs and the electropolymerized D-alanine (PoDA) film enhanced the electrocatalytic activity of the carbon paste electrode (CPE) toward Linezolid (LNZO). The fabricated sensor was characterized using FTIR, XRD, and SEM techniques. It exhibited excellent electro-oxidation performance toward LNZO, demonstrating high sensitivity, a very low detection limit, good selectivity, and acceptable reproducibility. Differential pulse voltammetry provided a wide linear range (0.005–0.1 µM) with a detection limit of 1.27 nM. Importantly, the sensor successfully detected LNZO in real samples, achieving recovery rates between 95.70% and 100.20%, confirming its effectiveness for practical applications the developed sensor confirmed the ability to identify LNZO in real samples, yielding acceptable recovery percentages within the range of 95.70% to 100.20%, proving the method’s effectiveness in practical applications.

Clozapine (CLZ); an atypical antipsychotic drug, is well known to have a significant role in managing schizophrenic patients with substance use disorder (SUD). Unfortunately, many patients are deprived of CLZ benefits due to its limited prescription. This is based upon concerns regarding the critical side effects of CLZ in case of overdosing especially, with the lack of accessible therapeutic drug monitoring (TDM) tools. In this contribution, a simple, accurate and sensitive electrochemical method is proposed for CLZ assay in human saliva. Unlike previously reported methods for TDM of CLZ that depends on invasive matrices as plasma and urine, this method employs electrochemical approaches in exploring human saliva as a patient-friendly alternative for assessing CLZ. The proposed method employs differential pulse voltammetry (DPV) with a sensitive and selective Ag-doped ZnO nanoparticles based carbon paste electrode (CPE). The adopted electrochemical sensor has not been previously reported for CLZ determination, despite it offers enhanced sensitivity together with simple synthesis. The synthesized nanoparticles were characterized through Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The developed sensor was optimized and validated as per FDA guidelines of bioanalytical methods. The linear range in saliva was 0.31–3.67 µmol/L and the lower limit of quantitation (LLOQ) was 0.31 µmol/L. The high reliability and applicability of the suggested method has strong potential to be integrated in a point-of-care testing (POCT) device to introduce more accessible TDM that enables smooth TDM of CLZ. Therefore, it opens pathways for broader and safe use of CLZ.

Graphical abstract

A reliable and sensitive RP-HPLC method was developed and validated for the accurate quantification of mesalamine in bulk and formulated pharmaceutical products. The analysis was carried out on a C18 column (150 mm × 4.6 mm, 5 μm) using a mobile phase of methanol: water (60:40 v/v), with a flow rate of 0.8 mL/min, and UV detection at 230 nm. Methanol: water (50:50 v/v) was used as the diluent. The method demonstrated excellent linearity across the concentration range of 10–50 µg/mL (y = 173.53x – 2435.64, R² = 0.9992), high accuracy with recoveries between 99.05% and 99.25% (%RSD < 0.32%), and outstanding precision with intra- and inter-day %RSD values below 1%. Robustness was confirmed under slight method variations (%RSD < 2%), and LOD and LOQ were found to be 0.22 µg/mL and 0.68 µg/mL, respectively. Forced degradation studies under acidic, basic, oxidative, thermal, and photolytic stress confirmed the method’s specificity and stability-indicating capability. Assay of a commercial mesalamine tablet (Mesacol^®, 800 mg label claim) showed a recovery of 99.91%, validating the method’s applicability for routine quality control and regulatory compliance.

Graphical Abstract

Objective

To rapidly characterize the chemical constituents of Polygoni Multiflori Radix and its processed form, Polygoni Multiflori Radix Preparata, utilizing ultra-high performance liquid chromatography coupled with quadrupole-orbitrap-linear ion trap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-Linear Ion Trap-MS).

Methods

Chromatographic separation was achieved on an ACQUITY UPLC BEH phenyl column (1.7 μm, 2.1 × 100 mm) employing a gradient elution of methanol (A) and 0.1% formic acid aqueous solution (B). Mass spectrometric analysis was conducted using a heated electrospray ionization (H-ESI) source operated in negative ion mode. Data processing was performed using Thermo Scientific Compound Discoverer 3.0 software, integrating a self-constructed Polygoni Multiflori Radix MS and MS/MS spectral database. Compounds with a mass error tolerance of ≤ |5| ppm were tentatively identified via freestyle software and further validated by comparison with previously reported literature data.

Results

A total of 231 chemical constituents were tentatively identified through online analysis, comprising 64 stilbene glycosides, 28 anthraquinones, 38 flavonoids, 45 polyphenols, 18 amino acids, 7 naphthalenes, 6 chromones, 3 alkaloids, 5 fatty acids, and 17 other components. Following 24 h of processing, the levels of stilbene glycosides, free anthraquinones, torachrysone, and torachrysone-8-O-β-D-glucoside were observed to decrease, while the concentrations of dianthrones and bound anthraquinones exhibited a significant reduction. In contrast, the content of gallic acid increased markedly.

Conclusions

These findings provide a robust scientific foundation for further exploration of the active and toxic components in Polygoni Multiflori Radix and its processed form, Polygoni Multiflori Radix Preparata, contributing to a deeper understanding of their pharmacological and toxicological profiles.

Graphical abstract

A low-cost and efficient activated carbon was prepared from banana peels for the removal of alizarin. Non-linear kinetic studies, isotherm models, and predictive models were used to study the adsorption process. The choice of the kinetic studies and isotherm models was based on the error functions of R², Adj.R², chi-square, SSE and ARE. The kinetic studies using intraparticle diffusion, pseudo-first-order, Elovich, and pseudo-second-order models fit the data well. It was concluded that the pseudo-second-order model best fitted the data, thus the mechanism was by chemisorption. Isotherm studies indicated that the Langmuir, Temkin, Dubinin-Radushkevich, and Freundlich models all describe the adsorption process. The mode was best described by the Freundlich model, thus, adsorption occurred on multilayer surfaces. The quadratic model, with a high R² value of 0.9740, accurately predicted the removal efficiency and identified dosage and concentration as the most significant factors. The optimized conditions were found to be 3.05 min, a pH of 5.55, a dosage of 0.014 g, and a concentration of 21.50 ppm, which resulted in a maximum removal efficiency of 92.18%. The artificial neural networks with a predictive capability (96.26%) and a correlation coefficient of 0.99999 for both training and validation sets was superior to the central composite design. This was confirmed through the comparison of the residual errors and the statistical error functions of SSE, MSE, RMSE and MAE. This study shows a dual approach of coupling activated carbon from banana peels with mathematical models to understand the adsorption process.

In this study, mesoporous barium titanate (BaTiO₃) was synthesized using a single-step solid-state reaction by blending TiO₂ and BaCO₃ followed by thermal treatment. The produced BaTiO₃ served as an effective adsorbent for the uptake of malachite green (MG) from aqueous media. The synthesized BaTiO₃ was subjected to characterization using XRD, FTIR, SEM, TEM, EDX, and BET, demonstrating the formation of a crystalline, mesoporous perovskite structure with an average crystallite size of 68.2 nm and a surface area of 28.1 m²/g. Although its surface area is moderate, BaTiO₃ had a substantial maximum adsorption capacity of 495.15 mg/g, attributable to its oxygen vacancies, electrostatic attraction, and robust chemisorption mechanisms. The effect of various experimental factors, for example, pH, initial MG concentration, adsorbent dosage, contact time, temperature, and ionic strength, on MG removal using batch adsorption experiments was investigated. Optimum MG removal was achieved at pH of 5.0, adsorbent dose of 10.0 mg, initial solution volume of 10.0 mL, contact time of 330 min., and temperature of 50 °C. Kinetic studies were consistent with pseudo-second order model and the Langmuir model provided the best description of the adsorption isotherm. Thermodynamic variables such as (ΔG°, ΔH°, and ΔS°) were determined, and it was shown that the adsorption was feasible, spontaneous, and endothermic. Effective MG removal of over 98% was demonstrated in real sample applications comprising models of industrial wastewater and water from the Nile River. The study revealed that MG could be successfully extracted from wastewater samples using BaTiO₃, which may be produced in a sustainable manner.

The present study included the first electrochemical synthesis of Betti bases in deep eutectic solvents as a green and sustainable method of synthesis. The reaction conditions were optimized by varying different factors like time and type of electrode material. The prepared compounds were utilized as fluorescent probe for mercury ions. The fluorescence intensity of the synthesized Betti base derivatives 4a-e was investigated and the highest fluorescence intensity was displayed by compound 4e (the 2-fluorophenyl derivative). The Betti base 4e showed excitation/emission peaks at 368/461 nm, respectively. The Betti based fluorescence was quenched by Hg²⁺ ions. The fluorescent probe responded linearly to Hg²⁺ concentration in the range of 0.2 to 10.0 µM. The limit of detection (LOD) was estimated to be 0.041 µM. The Stern-Volmer constant (K_sv) was calculated to be 2.69 ± 0.07 × 10⁵ M^-1.

Background

Antimicrobial resistance poses a growing threat to effective infection treatment, while imbalances in ascorbic acid (AA) levels are linked to various health issues. Nanotechnology offers innovative solutions, with carbon dot-based nanocomposites emerging as promising materials for both antimicrobial applications and sensitive detection of biomolecules. This study aimed to synthesize nitrogen-doped carbon dots (NCDs), copper oxide nanoparticles (CuO NPs), and their nanocomposites (CuO-NCDs), and to evaluate their electrochemical sensing of AA and antimicrobial activity.

Methods

NCDs were prepared via a hydrothermal treatment of citric acid and urea, and CuO NPs by precipitation of copper nitrate. Characterization by Ultraviolet–Visible (UV–Vis) spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) confirmed their optical properties, functional groups, crystallinity, and morphology.

Results

The CuO-NCD nanocomposite exhibited enhanced optical absorption with a reduced energy band gap (2.6 eV) compared to individual components. Electrochemical tests revealed a detection limit of 2.56 µM for AA and increased electrode surface area, indicating improved sensitivity and selectivity. Antimicrobial assays showed significant activity against Staphylococcus aureus, with a 24 mm inhibition zone at 200 mg/mL after 24 h.

Conclusions

These results demonstrate that CuO-NCD nanocomposites hold potential as dual-function materials for effective AA detection and combating microbial infections.

Extracting and reusing valuable components from iron-rich waste materials pose significant challenges but are crucial for economic benefits and environmental sustainability. In a recent study, Particles of γ-Fe₂O₃ were produced from different iron-rich waste materials. Additionally, a simple, efficient, and eco-friendly procedure for synthesizing 1-(benzothiazolylamino)methyl-2-naphthol derivatives was studied using iron oxide nanoparticles obtained from steel waste recycling as a catalyst. The final products were thoroughly characterized by FT-IR, ¹H NMR, and ¹³C NMR spectroscopy, while the structure of γ-Fe₂O₃ was comprehensively analyzed using XRD, FT-IR, SEM, VSM, and TGA techniques. Molecular docking analysis was conducted to position the compounds within the active site of E. coli 2EG7, aiming to understand their potential mechanism of action, binding affinity, and how the molecules are oriented at the receptor's active site. The results revealed that all the synthesized compounds interact with the agonist within the active site of the 2EG7 protein. These findings suggest promising potential for these compounds as effective antibacterial agents. The in vitro antibacterial activity of the synthesized compounds was studied, and the MIC value was calculated using the broth dilution method.