Search Results (38)

Protein glycation and oxidation contribute to the pathogenesis of neurodegenerative diseases. This study evaluated the antiglycative and antioxidative effects of donepezil, rivastigmine, galantamine, memantine, lamotrigine, sodium valproate, and carbamazepine using bovine serum albumin (BSA) as a model protein. Glycation was induced with fructose, ribose, or methylglyoxal (MGO), and oxidation with chloramine T (ChT). Concentrations of glycation products—Amadori products (APs), amyloid cross-β structure (βA), argpyrimidine (ARG), crossline (CRO), vesperlysine (VES), pentosidine (PEN), total AGEs and glycoxidation products—dityrosine (DT), kynurenine (KN), N-formylkynurenine (NFK) as well as oxidation biomarkers, total thiols (TTs), protein carbonyls (PCs), and advanced oxidation protein products (AOPPs), were determined via spectrophotometric and spectrofluorimetric methods. Molecular docking and a systematic literature review (PRISMA) complemented the experimental data. Lamotrigine showed the strongest antiglycative and antioxidative effects, surpassing aminoguanidine in reducing ARG, PEN, DT, and NFK levels. In contrast, donepezil markedly increased APs, βA, ARG, VES, DT, and PEN, suggesting proglycative and pro-oxidative activity. Docking revealed a high affinity of donepezil for RAGE (–7.2 kcal/mol), possibly explaining its impact on carbonyl stress. Overall, anti-dementia drugs showed weak to moderate antiglycative potential, with lamotrigine being the most effective. Full article

Trolox, a water-soluble analog of vitamin E, is widely used as a reference antioxidant in in vitro biochemical assays. However, its intracellular redox behavior is known to vary depending on both concentration and oxidative context. In this study, we investigated the dose-dependent antioxidant and prooxidant effects of Trolox in two cellular models, HeLa cells and 3T3 cells exposed for 1 h to increasing concentrations (2–160 µM), under both basal conditions and oxidative stress induced by hydrogen peroxide. Intracellular oxidative changes were assessed using the oxidative stress-sensitive fluorescent probe CM-H₂DCFDA. Under basal conditions, Trolox exerted slight dose-dependent antioxidant behavior in 3T3 cells on the basal production of ROS in concentrations ranging from 2 µM to 160 µM. In contrast, in HeLa cells Trolox displayed a biphasic activity: antioxidant at low doses (≤10 µM) and a switch to prooxidant behavior at higher concentrations. Under H₂O₂-induced stress, in HeLa cells Trolox retained antioxidant activity at low concentrations (≤10 µM), but this effect gradually declined at higher doses, disappearing around 80 µM and shifting to a slight prooxidant effect at 160 µM. Confocal microscopy confirmed the spectrofluorimetric results. Conversely, 3T3 cells exhibited an early shift toward prooxidant activity already at 10 µM. These findings highlight that the Trolox redox activity is determined not only by concentration but also by cell-specific intracellular environment and redox state. The study suggests caution against generalized antioxidant use of Trolox and highlights the need for specific dose–response evaluations in specific cell types and biological settings. Full article

A tandem UV–Vis and fluorescence spectroscopy method was developed for the detection of Pd(II) ions in ethanol. The formation of a complex between Pd(II) ions and tropaeolin OO (TR OO) is accompanied by a change in the color of the solution and evolution of the characteristic UV–Vis as well as fluorescence spectra. The optimal detection conditions were achieved at a 3:1 (mL/mL) volume ratio of Pd(II) to TR OO, at 50 °C. UV–Vis spectroscopy enabled the detection of complex formation process over time, while fluorescence spectroscopy allowed a rapid response within 10 min. The limit of detection (LOD) of Pd(II) ions using UV–Vis spectrophotometry was 10 μmol/dm³ at 535 nm. For spectrofluorimetric detection, the LOD was 10 μmol/dm³, with an emission signal observed at 630 nm after 10 min. The kinetics studies showed a stepwise complex formation pathway, supported by DFT calculations. The performance of the method was verified in the presence of interfering metal ions, including Li(I), Na(I), Al(III), Ni(II), Mg(II), Ca(II), Co(II), and Zn(II), confirming its applicability in complex matrices. This approach provides efficient palladium determination in organic solvents, contributing to sustainable practices in metal recycling. Full article

This study investigated the influence of β-cyclodextrin (βCD) on the micellization behavior of two bile salt surfactants, sodium deoxycholate (NaDC) and sodium cholate (NaC), in aqueous solutions. Tensiometry, conductometric, and spectrofluorimetric techniques were employed to determine critical micelle concentrations (CMCs) in the presence of varying concentrations of βCD, as well as in the presence of inorganic salts (NaCl and CsCl). The results showed that βCD forms inclusion complexes with both bile salts, leading to an increase in their CMCs, consistent with a competitive interaction between micelle formation and complexation. The inclusion constants, determined graphically, revealed stronger complexation for NaDC than NaC, attributed to differences in hydrophobic surface area. Salt addition decreased the CMC of both surfactants, with CsCl having a more pronounced effect. However, salt presence also modulated the inclusion complex formation, suggesting specific ion effects influence the availability and behavior of βCD. These findings contribute to the understanding of bile salt–cyclodextrin interactions and their modulation by electrolytes, with implications for drug delivery and supramolecular chemistry. Full article

A novel design for vortex-assisted liquid–liquid microextraction (VALLME), combined with spectrofluorimetric determination (FLD), was proposed and successfully tested for determining picric acid (PA) in water samples. This fluorescence method is based on the formation of an ion associate (IA) through electrostatic interactions, which serves as the analytical species for fluorescence measurement in the presence of the basic polymethine dye Astrafloksin (AF). The approach aims to minimize the volume of the extraction phase, aligning with the principles of green analytical chemistry. The calibration curve was linear from 0.92 to 11.45 µg L⁻¹, with an R² of 0.9930. LOD was 0.40 µg L⁻¹. Density functional theory (DFT) calculations, supported by analysis of van der Waals and electrostatic interionic attraction, helped explain the experimentally observed selectivity of the AF cation for picrate compared to other selected phenols. Theoretical solubility descriptors of the proposed IA provided insight into the extraction of IA from water to the n-amyl acetate phase. This VALLME-FLD method represents a significant advancement in PA determination, characterized by high sensitivity, selectivity, and procedural simplicity. It minimizes the use of organic solvents, facilitates direct sample preparation, and shortens analysis time. The developed method was successfully applied to real samples. Full article

Two new Ru(II) complexes, mononuclear [RuCl₂(η⁶-p-cymene)(3,4-dmph-κN)] (1) and the binuclear complex [{RuCl(η⁶-p-cymene)}₂(μ-Cl)(μ-3,4-dmph-κ²N,N′)]Cl (2; 3,4-dmph = 3,4-dimethylphenylhydrazine), are synthesized and experimentally and theoretically structurally characterized utilizing ¹H and ¹³C NMR and FTIR spectroscopy, as well as DFT calculations. Degradation product of 2, thus ([{RuCl(η⁶-p-cymene)}₂(μ-Cl)(μ-3,4-dmph-κ²N,N′)][RuCl₃(η⁶-p-cymene)] (2b) was characterized with SC-XRD. In the crystals of 2b, the cationic and anionic parts interact through N-H^...Cl hydrogen bridges. The spectrofluorimetric measurements proved the spontaneity of the binding processes of both complexes and HSA. Spin probing EPR measurements implied that 1 and 2 decreased the amount of bound 16-doxylstearate and implicated their potential to bind to HSA more strongly than the spin probe. The cytotoxicity assessment of both complexes against the MDA-MB-231 and MIA PaCa-2 cancer cell lines demonstrated a clear dose-dependent decrease in cell viability and no effect on healthy HS-5 cells. Determination of the malondialdehyde and protein carbonyl concentrations indicated that new complexes could offer protective antioxidant benefits in specific cancer contexts. Gel electrophoresis measurements showed the reduction in MMP9 activity and indicated the potential of 1 in limiting the cancer cells’ invasion. The annexin V/PI apoptotic assay results showed that 1 and 2 exhibit different selectivity towards MIA PaCa-2 and MDA-MB-231 cancer cells. A comparative molecular docking analysis of protein binding, specifically targeting acetylcholinesterase (ACHE), matrix metalloproteinase-9 (MMP-9), and human serum albumin (HSA), demonstrated distinct binding interactions for each complex. Full article

Black cumin seeds (Nigella sativa) and black cumin seed oil (BCSO) exhibit various pharmacological activities, most of which are attributed to the presence of thymoquinone (TQ). TQ, however, is characterized by low stability at elevated temperatures and instability in aqueous environments. In this study, the spectroscopic properties of TQ were used to monitor changes in TQ content in BCSO subjected to thermal exposure. Simultaneously, the influence of the presence of TQ on the antioxidant properties of this oil was determined. The used spectrofluorimetric and chromatographic method quantified the presence of TQ. The antiradical properties of the oil in different stages of thermal oxidation degradation were determined by the DPPH method. The measured antiradical activity of the oil, depending on the exposure conditions used, revealed the difference correlated with the content of the TQ. However, the presence in BCSO of other bioactive components, like phenols, had a more significant influence on its total antioxidant capacity. Furthermore, our study, for the first time, focused on the rise in TQ content in the oil during thermal storage, indicating a new method to enhance the TQ content in BCSO. Full article

Background: The aim of this research is the synthesis and characterization of coumarin-palladium complex and the investigation of the cytotoxicity of both the ligand and the complex. Methods: The palladium( II) complex (CC) was obtained in the reaction between (E)-3-(1-((4-hydroxy-3-methoxyphenyl)amino)ethylidene)-2,4-dioxochroman-7-yl-acetate (CL) and potassium-tetrachloropalladate(II) and characterized using IR and NMR spectra, experimentally and theoretically. Cytotoxicity of CL and CC were determined for human cervical carcinoma HeLa, ovarian cancer A2780, hormone dependent breast cancer MCF7, and colorectal cancer HCT116 lines. The interaction of investigated compounds with HSA was followed by spectrofluorimetric method. The binding mechanism in the active pocket was assessed via molecular docking simulations. Results: A low mean absolute error between experimental and theoretical data proved that the optimized structure corresponded to the experimental one. Both compounds showed a satisfactory selectivity index towards neoplastic cells. The binding affinity of tested compounds to the HSA were confirmed. The molecular docking showed a much lower change in the Gibbs free energy of binding for CC compared to CL. Conclusions: The obtained results revealed that CL and CC exhibit significant effects on several cancer cell lines and good binding properties to HSA, while molecular docking discovered that CC has the most pronounced activity against alpha-fetoprotein. Full article

The pyridoxal-semicarbazone (PLSC) ligand and its transition metal complexes have shown significant biological activity. In this contribution, a novel nickel(II)-PLSC complex, [Ni(PLSC)(SO₄)(H₂O)₂], was obtained, and its structure was determined by X-ray crystallographic analysis, FTIR, and UV-VIS spectroscopy. The sulfate ion is directly coordinated to the central metal ion. The intermolecular stabilization interactions were examined using Hirshfeld surface analysis. The crystal structure was optimized by a B3LYP functional using two pseudopotentials for nickel(II) (LanL2DZ and def2-TZVP) together with a 6-311++G(d,p) basis set for non-metallic atoms. The experimental and theoretical bond lengths and angles were compared, and the appropriate level of theory was determined. The stabilization interactions within the coordination sphere were investigated by the Quantum Theory of Atoms in Molecules (QTAIM). The antioxidant activity towards hydroxyl and ascorbyl radicals was measured by EPR spectroscopy. The interactions between Human Serum Albumin (HSA) and the complex were examined by spectrofluorimetric titration and a molecular docking study. The mechanism of binding to DNA was analyzed by complex fluorescence quenching, potassium iodide quenching, and ethidium bromide displacement studies in conjunction with molecular docking simulations. Full article

In this study, adsorbents based on molecularly imprinted polymers (MIPs) in two solid-phase extraction application forms, pipette tip and magnetic extraction, were used for the selective extraction of coumarins. The pipette-tip solid-phase extraction reduced solvent volumes; the magnetic MIP extraction was simple and effective for phase separation. Parameters affecting extraction, such as the amount of adsorbent, type of washing solvent, volume of the elution solvent, and extraction times for magnetic extraction, were optimized. The MIP-based adsorbents displayed high selectivity and extraction efficiency, resulting in recoveries ranging from 70.3 to 102.0% (RSD % less than 5.5%) for five coumarins under study, 6,7-dihydroxycoumarin-6-β-D-glucoside, coumarin, 7-methoxycoumarin, 6-methylcoumarin, and dicoumarol. The extracts were analyzed by high-performance liquid chromatography with diode array (DAD) and fluorescence (FLD) detectors, reaching limits of quantification of 0.5 and 0.9 µg·mL⁻¹ for coumarin and dicoumarol detected by DAD and 0.001–0.012 µg·mL⁻¹ for the other prohibited simple coumarins when used as a fragrance (detected by FLD). The proposed method was validated and its applicability was shown for the analysis of cosmetic samples like shower gel and perfume. Full article

Per- and polyfluoroalkyl substances (PFAS) belong to a group of synthetic compounds that have recently raised concerns about human health and environmental quality due to their great prevalence, degradation resistance, and potential toxicity. This review focuses on the applications of PFAS and their effects on human health. Specific emphasis has been laid on (i) the application/use of PFAS, (ii) sources and distribution of PFAS in diverse environmental compartments, and (iii) the impact of PFAS on human health. Significant health effects on humans are associated with exposure to PFAS, i.e., immunotoxicity, thyroid and kidney disorders, cancer, etc. Conclusions obtained from PFAS studies demonstrate that inadequate evidence should not be used to justify delaying risk reduction steps for PFAS alternatives. PFAS can be determined in different environmental matrices using both traditional analytical approaches, i.e., liquid chromatography coupled with mass spectrometry (LC-MS/MS) and semi-quantitative and passive sampling, and advanced analytical methods with colorimetric, spectrofluorimetric, and electrochemical detection. Traditional methods are costly and not broadly available, while the emerging, cost-effective methods are less sensitive and unable to meet regulatory exposure limits. There is still a significant number of studies to be performed to fully comprehend the real contamination by PFAS. Full article

The aim of this study was to determine the Se concentration in the main tissues of beef cattle and to evaluate the differences in tissue distribution between animals with different selenium status. Selenium concentration was determined in the serum, longissimus dorsi muscle, semitendinosus muscle, kidney, heart, liver, spleen and lungs of cows, heifers and beef bulls, using spectrofluorimetric method. Despite receiving supplementation, 55.6% animals demonstrated an optimal Se level, while 44.4% were deficient. The mean serum Se concentration was significantly higher (p < 0.05) in animals with a normal Se status than in Se-deficient animals. Differences in Se tissue distribution were observed between Se-deficient animals and those with normal Se status. The organs most susceptible to Se deficiency are the semitendinosus muscle, lungs, heart and liver. In both normal and Se-deficient animals, significantly higher Se concentrations were observed in the kidney than other organs (p < 0.05), and the lowest in the muscles. As Se deficiencies can be found among supplemented animals, the level of Se should be monitored in beef cattle in order to detect possible Se deficiencies, which may have negative health effects for animals and reduce the value of animal products as a source of Se in the human diet. Full article

Pharmaceutical, food, and cosmetic formulations often contain binary or ternary surfactant mixtures with synergistic interactions amongst micellar building blocks. Here, a ternary mixture of the surfactants hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and sodium deoxycholate is examined to see if the molar fractions of the surfactants in the ternary mixed micellar pseudophase are determined by the interaction coefficients between various pairs of the surfactants or by their propensity to self-associate. Critical micelle concentrations (CMC) of the analyzed ternary mixtures are determined experimentally (spectrofluorimetrically using pyrene as the probe molecule). Thermodynamic parameters of ternary mixtures are calculated from CMC values using the Regular Solution protocol. The tendency for monocomponent surfactants to self-associate (lower value of CMC) determines the molar fractions of surfactant in the mixed micelle if there is no issue with the packing of the micelle building units of the ternary mixed micelle. If a more hydrophobic surfactant is incorporated into the mixed micelle, the system (an aqueous solution of surfactants) is then the most thermodynamically stabilized. Full article

Foodborne mycotoxins are a significant food safety risk in developing countries. Our objective was to determine the occurrence of and exposure levels to aflatoxins (AFs) and fumonisins (FBs) in maize intended for human and animal consumption in food-insecure regions of western Honduras. Total AFs and FBs were quantified with a monoclonal antibody-based affinity spectrofluorimetric method. FBs were detected in 614/631 samples of maize destined for human consumption at 0.3 to 41 mg/kg (mean, 2.7 mg/kg). Of the 614 positive samples, 147 had FB levels exceeding the U.S. Food and Drug Administration (FDA) advisory threshold of 4.0 mg/kg. AFs were detected in 109/631 samples of maize for human consumption with concentrations between 1.0 and 490 µg/kg (mean, 10 µg/kg). AF levels in 34 samples exceeded the FDA regulatory limit (i.e., 20 µg/kg). The average probable daily intake of AFs in western Honduras ranged from 0 to 260 ng/kg body weight/day, and for FBs, the average probable daily intake ranged from 17 to 53 μg/kg body weight/day. AFs and FBs co-occurred in 106/631 samples with 60 samples containing both toxins at levels greater than the FDA regulatory levels. Samples of maize intended for animal feed had significantly higher AF (mean, 22 µg/kg) and FB (mean, 7.6 mg/kg) contamination levels than those observed in samples destined for human consumption. Thus, the maize supply chain in western Honduras is contaminated with mycotoxins at levels that pose health risks to both humans and livestock. More effective mycotoxin surveillance and implementation of effective mitigation strategies are needed to reduce mycotoxin contamination and exposure. Full article

Lorlatinib (LOR) is a third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor drug. The Food and Drug Administration (FDA) has granted an approval for the use of LOR as a first therapeutic intervention for individuals diagnosed with ALK-positive metastatic and advanced non-small-cell lung cancer (NSCLC). The present study outlines, for the first time, the development and validation of an innovative microwell-based spectrofluorimetric (MW-SFL) method for the quantification of LOR. The proposed method involved the enhancement of the weak native fluorescence of LOR by its micellization into the sodium lauryl sulfate (SLS) micelles. The procedures of the method were conducted in white opaque plates with 96 microwells, and the enhanced fluorescence signals were measured by a fluorescence plate reader at 405 nm after excitation at 310 nm. The measured relative fluorescence intensity (RFI) had a linear relationship with LOR concentrations in the range of 60–1600 ng mL⁻¹. The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 19 and 56 ng mL⁻¹, respectively. The method’s accuracy and precision were assessed using a recovery study; the recovery values ranged from 99.98% to 101.40%, accompanied by relative standard deviation (RSD) values of 0.42% to 1.59%. The proposed MW-SFL method combined the advantages of the intrinsically high sensitivity of the spectrofluorimetric measurement and the excellent throughput of the microwell-based approach. The results proved the method is effective in the determination of LOR in its pharmaceutical tablets, tablet dissolution testing, as well as in spiked urine with a high degree of precision and accuracy. The MW-SFL method is notable for its simple procedures and utilization of water as a solvent, as well as minimal quantities of sample solutions. These features align with its ecofriendly approach to green chemistry principles. These advantages gave the proposed MW-SFL method a high potential value for the determination of LOR in clinical and quality control laboratories. Full article