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1.
Int J Mol Sci ; 22(17)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34502323

RESUMO

The aim of the study was the multi-elemental analysis of aqueous humor (AH) collected from patients undergoing cataract surgery. The study included: 16 patients with age-related macular degeneration AMD (99 controls), 10 patients with retinopathy (105 controls), 61 patients with hypertension (54 controls), and 33 patients with coexisting diabetes (82 controls). The control groups were recruited from patients with a lack of co-existing disease characterizing the specified studied group. The measurements were performed by the use of inductively coupled plasma optical emission spectrometry (ICP-OES). The statistical analysis was carried out using non-parametric testing (Mann-Whitney U). The level of significance was set at p = 0.05. The data obtained revealed substantial variations in elemental composition between the test groups in comparison to the controls. However, the significant variations concerned only a few elements. The phosphorous (P) level and the ratio of P/Ca were significant in retinopathy and diabetes, whereas cobalt (0.091 ± 0.107 mg/L vs. 0.031 ± 0.075 mg/L; p = 0.004) was significant in AMD. In co-existing hypertension, the levels of tin (0.293 ± 0.409 mg/L vs. 0.152 ± 0.3 mg/L; p = 0.031), titanium (0.096 ± 0.059 mg/L vs. 0.152 ± 0.192 mg/L; p = 0.045), and ruthenium (0.035 ± 0.109 mg/L vs. 0.002 ± 0.007 mg/L; p = 0.006) varied in comparison to the controls. The study revealed inter-elemental interactions. The correlation matrices demonstrated the domination of the positive correlations, whereas negative correlations mainly concerned sodium.

2.
Molecules ; 26(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34443574

RESUMO

Natural extracts are a rich source of biomolecules that are useful not only as antioxidant drugs or diet supplements but also as complex reagents for the biogenic synthesis of metallic nanoparticles. The natural product components can act as strong reducing and capping substrates guaranteeing the stability of formed NPs. The current work demonstrates the suitability of extracts of Camellia sinensis, Ilex paraguariensis, Salvia officinalis, Tilia cordata, Levisticum officinale, Aegopodium podagraria, Urtica dioica, Capsicum baccatum, Viscum album, and marine algae Porphyra Yezoensis for green synthesis of AgNPs. The antioxidant power of methanolic extracts was estimated at the beginning according to their free radical scavenging activity by the DPPH method and reducing power activity by CUPRAC and SNPAC (silver nanoparticle antioxidant capacity) assays. The results obtained by the CUPRAC and SNAPC methods exhibited excellent agreement (R2~0.9). The synthesized AgNPs were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), dynamic light scattering (DLS) particle size, and zeta potential. The UV-vis absorption spectra showed a peak at 423 nm confirming the presence of AgNPs. The shapes of extract-mediated AgNPs were mainly spherical, spheroid, rod-shaped, agglomerated crystalline structures. The NPs exhibited a high negative zeta potential value in the range from -49.8 mV to -56.1 mV, proving the existence of electrostatic stabilization. FTIR measurements indicated peaks corresponding to different functional groups such as carboxylic acids, alcohol, phenol, esters, ethers, aldehydes, alkanes, and proteins, which were involved in the synthesis and stabilization of AgNPs. Among the examined extracts, green tea showed the highest activity in all antioxidant tests and enabled the synthesis of the smallest nanoparticles, namely 62.51, 61.19, and 53.55 nm, depending on storage times of 30 min, 24 h, and 72 h, respectively. In turn, the Capsicum baccatum extract was distinguished by the lowest zeta potential, decreasing with storage time from -66.0 up to -88.6 mM.


Assuntos
Antioxidantes/síntese química , Antioxidantes/farmacologia , Nanopartículas Metálicas , Extratos Vegetais/química , Prata/química , Prata/farmacologia , Antioxidantes/química , Compostos de Bifenilo/química , Técnicas de Química Sintética , Química Verde , Picratos/química
3.
Materials (Basel) ; 14(15)2021 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-34361329

RESUMO

Natural extracts are the source of many antioxidant substances. They have proven useful not only as supplements preventing diseases caused by oxidative stress and food additives preventing oxidation but also as system components for the production of metallic nanoparticles by the so-called green synthesis. This is important given the drastically increased demand for nanomaterials in biomedical fields. The source of ecological technology for producing nanoparticles can be plants or microorganisms (yeast, algae, cyanobacteria, fungi, and bacteria). This review presents recently published research on the green synthesis of nanoparticles. The conditions of biosynthesis and possible mechanisms of nanoparticle formation with the participation of bacteria are presented. The potential of natural extracts for biogenic synthesis depends on the content of reducing substances. The assessment of the antioxidant activity of extracts as multicomponent mixtures is still a challenge for analytical chemistry. There is still no universal test for measuring total antioxidant capacity (TAC). There are many in vitro chemical tests that quantify the antioxidant scavenging activity of free radicals and their ability to chelate metals and that reduce free radical damage. This paper presents the classification of antioxidants and non-enzymatic methods of testing antioxidant capacity in vitro, with particular emphasis on methods based on nanoparticles. Examples of recent studies on the antioxidant activity of natural extracts obtained from different species such as plants, fungi, bacteria, algae, lichens, actinomycetes were collected, giving evaluation methods, reference antioxidants, and details on the preparation of extracts.

4.
Int J Mol Sci ; 22(7)2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33805962

RESUMO

About 70 million people suffer from epilepsy-a chronic neurodegenerative disease. In most cases, the cause of the disease is unknown, but epilepsy can also develop as the result of a stroke, trauma to the brain, or the use of psychotropic substances. The treatment of epilepsy is mainly based on the administration of anticonvulsants, which the patient must most often use throughout their life. Despite significant progress in research on antiepileptic drugs, about 30% of patients still have drug-resistant epilepsy, which is insensitive to pharmacotherapy used so far. In our recent studies, we have shown that 4-alkyl-5-aryl-1,2,4-triazole-3-thiones act on the voltage-gated sodium channels and exhibit anticonvulsant activity in an MES (maximal electroshock-induced seizure) and 6Hz test in mice. Previous studies have shown their beneficial toxic and pharmacological profile, but their effect on a living organism during chronic use is still unknown. In the presented study, on the basis of the previously conducted tests and the PAMPA (parallel artificial membrane permeability assay) BBB (blood-brain barrier) test, we selected one 1,2,4-triazole-3-thione derivative-TP-315-for further studies aimed at assessing the impact of its chronic use on a living organism. After long-term administration of TP-315 to Albino Swiss mice, its effect on the functional parameters of internal organs was assessed by performing biochemical, morphological, and histopathological examinations. It was also determined whether the tested compound inhibits selected isoforms of the CYP450 enzyme system. On the basis of the conducted tests, it was found that TP-315 does not show nephrotoxic nor hepatotoxic effects and does not cause changes in hematological parameters. In vitro tests showed that TP-315 did not inhibit CYP2B6, CYP2D6, CYP3A4, or CYP3A5 enzymes at the concentration found in the serum of mice subjected to long-term exposure to this compound.


Assuntos
Anticonvulsivantes/administração & dosagem , Barreira Hematoencefálica/efeitos dos fármacos , Doenças Neurodegenerativas/metabolismo , Triazóis/administração & dosagem , Animais , Sistema Enzimático do Citocromo P-450 , Eletrochoque , Rim/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Permeabilidade , Isoformas de Proteínas , Convulsões/metabolismo
5.
Molecules ; 25(24)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353137

RESUMO

The 2,2-diphenyl-1-picrylhydrazyl (DPPH)-reverse phase (RP)-HPLC-diode array detector (DAD) method was tested on standard antioxidants (AOs), i.e., reduced glutathione (GSH), ascorbic acid (vitamin C), and alcoholic extracts of A. podagraria L. An elaborated HPLC procedure enabled the simultaneous measurement of the redox couple DPPH-R (2,2-diphenyl-1-picrylhydrazyl radical)/DPPH-H (2,2-diphenyl-1-picrylhydrazine). Both forms were fully separated (Rs = 2.30, α = 1.65) on a Zorbax Eclipse XDB-C18 column eluted with methanol-water (80:20, v/v) and detected at different wavelengths in the range of 200-600 nm. The absorbance increases of the DPPH-H as well as the DPPH-R peak inhibition were measured at different wavelengths in visible and UV ranges. The chromatographic method was optimized, according to reaction time (slow, fast kinetics), the linearity range of DPPH radical depending on the detection conditions as well as the kind of the investigated antioxidants (reference chemicals and the ground elder prepared from fresh and dry plants). The scavenging capacity was expressed by the use of percentage of peak inhibition and the IC50 parameters. The evaluated extracts displayed antioxidant activity, higher than 20% inhibition against 350 µM DPPH free radical. The results show that extract prepared from dry plants in the ultrasonic bath exhibits the highest antioxidant potential (IC50 = 64.74 ± 0.22 µL/mL).


Assuntos
Antioxidantes/farmacologia , Apiaceae/química , Extratos Vegetais/farmacologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Compostos de Bifenilo/antagonistas & inibidores , Cromatografia Líquida de Alta Pressão , Picratos/antagonistas & inibidores , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação
6.
Materials (Basel) ; 13(22)2020 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-33233399

RESUMO

Zeolites are materials with known sorption properties. The sorption is thought to progress mainly by ion exchange with Na+, K+, Mg2+, Ca2+ or H+ from the zeolite exchange sites. The aim of the study was to compare the sorption properties of natural and synthetic zeolites on the example of the removal of selected metals from aqueous acidic solutions. Uptake experiments for selected ions of chromium, manganese, selenium, nickel, cobalt, and iron were performed using the batch and kinetic column methods. The sorption of the individual metal ions in mg per 1g of sorbent was determined for each sorbent. The relative affinity sequence of the examined cations toward the various sorbent was presented. The Langmuir model was used to model the adsorption equilibrium. Vermiculite under 1 mm of diameter (SF), Na-X, and Na-A were proved to be the most suitable for the individual uptake of studied metal ions. It was observed that the behavior of selenium ions differed from the remaining ones which was interpreted that selenium undergoes adsorption in the anionic form. The fixed-bed column studies were performed using Na-A, ensuring the sorption of selenium in the presence of iron(III) ions. The experiments were conducted using Na-X zeolite pre-loaded by Fe(III) as well as unmodified sorbent eluted by an equimolar mixture containing 100 ppm of Fe and Se. Obtained results prove that selenium sorption improves if other metal ions such as iron appear in the acidic solution. That efficient selenium sorption conditions can be applied to remove selenium which was recognized as toxic at higher levels.

7.
Int J Mol Sci ; 21(17)2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32872533

RESUMO

Ionic liquids (ILs) are solvents with salt structures. Typically, they contain organic cations (ammonium, imidazolium, pyridinium, piperidinium or pyrrolidinium), and halogen, fluorinated or organic anions. While ILs are considered to be environmentally-friendly compounds, only a few reasons support this claim. This is because of high thermal stability, and negligible pressure at room temperature which makes them non-volatile, therefore preventing the release of ILs into the atmosphere. The expansion of the range of applications of ILs in many chemical industry fields has led to a growing threat of contamination of the aquatic and terrestrial environments by these compounds. As the possibility of the release of ILs into the environment s grow systematically, there is an increasing and urgent obligation to determine their toxic and antimicrobial influence on the environment. Many bioassays were carried out to evaluate the (eco)toxicity and biodegradability of ILs. Most of them have questioned their "green" features as ILs turned out to be toxic towards organisms from varied trophic levels. Therefore, there is a need for a new biodegradable, less toxic "greener" ILs. This review presents the potential risks to the environment linked to the application of ILs. These are the following: cytotoxicity evaluated by the use of human cells, toxicity manifesting in aqueous and terrestrial environments. The studies proving the relation between structures versus toxicity for ILs with special emphasis on directions suitable for designing safer ILs synthesized from renewable sources are also presented. The representants of a new generation of easily biodegradable ILs derivatives of amino acids, sugars, choline, and bicyclic monoterpene moiety are collected. Some benefits of using ILs in medicine, agriculture, and the bio-processing industry are also presented.


Assuntos
Líquidos Iônicos/química , Líquidos Iônicos/toxicidade , Biodegradação Ambiental , Poluentes Ambientais/química , Poluentes Ambientais/toxicidade , Estrutura Molecular , Relação Quantitativa Estrutura-Atividade
8.
Materials (Basel) ; 13(11)2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32532041

RESUMO

The cell membrane is a complex system that consists of lipids, proteins, polysaccharides, and amphiphilic phospholipids. It plays an important role in ADME processes that are responsible for the final pharmaceutical effects of xenobiotics (bioavailability, activity). To study drug-membrane interaction at the molecular level, several high-performance liquid chromatography (HPLC) membrane model systems have been proposed which are mimicking mainly its lipid character. The aim of this work was to study interactions of new synthesized antiepileptic compounds of 4-alkyl-5-(3-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione derivatives with Chirobiotic column containing glycoprotein ligand attached to the silica matrix. The affinity of the analytes to immobilized glycoprotein ligand was examined chromatographically in reversed-phase mode. The thermodynamics of interactions between bioactive compounds and teicoplanin was studied in terms of the van't Hoff linear relationship ln k vs. 1/T in the range of 5-45 °C. Change in enthalpy (ΔH°), change in entropy (ΔS°) and change in Gibbs free energy (ΔG°) were estimated utilizing graphical extrapolation and interpolation methods. The density functional theory (DFT) approach and docking simulations were used to get the molecular interpretation and prove the obtained experimental results. Cross-correlations of chromatographic and thermodynamic parameters with non-empirical topological and quantum chemical indices suggest that the polarizability of analytes appears to be responsible for the interactions of the tested molecules with teicoplanin and, ultimately, their retention on the column. Experimental and theoretical parameters were subjected to statistical analysis using regression models. Partial least squares (PLS) regression model showed the usefulness of the experimentally measured parameter φ0 (MeOH) to discriminate between anticonvulsant active and inactive 1,2,4-triazole-3-thione derivatives. Obtained results point out the usefulness of interaction of potential anticonvulsants with glycoprotein class of compounds to anticipate their activity.

9.
Int J Mol Sci ; 21(12)2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32549300

RESUMO

Ionic liquids (ILs) are chemical compounds composed of ions with melting points below 100 °C exhibiting a design feature. ILs are commonly used as the so-called green solvents, reagents or highly efficient catalysts in varied chemical processes. The huge application potential of ionic liquids (IL) justifies the growing interest in these compounds. In the last decade, increasing attention has been devoted to the development of new methods in the synthesis of stable chiral ionic liquids (CILs) and their application in various separation techniques. The beginnings of the successful use of CILs to separate enantiomers date back to the 1990 s. Most chiral ILs are based on chiral cations or chiral anions. There is also a limited number of CILs possessing both a chiral cation and a chiral anion. Due to the high molecular diversity of both ions, of which at least one has a chiral center, we have the possibility to design a large variety of optically active structures, thus expanding the range of CIL applications. Research utilizing chiral ionic liquids only recently has become more popular. However, it is the area that still has great potential for future development. This review aimed to describe the diversity of structures, properties and examples of applications of chiral ionic liquids as new chiral solid materials and chiral components of the anisotropic environment, providing chiral recognition of enantiomeric analytes, which is useful in liquid chromatography, countercurrent chromatography and other various CIL-based extraction techniques including aqueous biphasic (ABS) extraction systems, solid-liquid two-phase systems, liquid-liquid extraction systems with hydrophilic CILs, liquid-liquid extraction systems with hydrophobic CILs, solid-phase extraction and induced-precipitation techniques developed in the recent years. The growing demand for pure enantiomers in the pharmaceutical and food industries sparks further development in the field of extraction and separation systems modified with CILs highlighting them as affordable and environmentally friendly both chiral selectors and solvents.


Assuntos
Fracionamento Químico/métodos , Líquidos Iônicos/química , Anisotropia , Catálise , Indústria Farmacêutica , Indústria Alimentícia , Solventes/química , Estereoisomerismo
10.
Rev Environ Contam Toxicol ; 252: 51-96, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31286265

RESUMO

In the past two decades, increased production and usage of metallic nanoparticles (NPs) have inevitably increased their discharge into the different compartments of the environment, which ultimately paved the way for their uptake and accumulation in various trophic levels of the food chain. Due to these issues, several questions have been raised on the usage of NPs in everyday life and have become a matter of public health concern. Among the metallic NPs, Cu-based NPs have gained popularity due to their cost-effectiveness and multifarious promising uses. Several studies in the past represented the phytotoxicity of Cu-based NPs on plants. However, comprehensive knowledge is still lacking. Additionally, the impact of Cu-based NPs on soil organisms such as agriculturally important microbes, fungi, mycorrhiza, nematode, and earthworms is poorly studied. This review article critically analyses the literature data to achieve a more comprehensive knowledge on the toxicological profile of Cu-based NPs and increase our understanding of the effects of Cu-based NPs on aquatic and terrestrial plants as well as on soil microbial communities. The underlying mechanism of biotransformation of Cu-based NPs and the process of their penetration into plants have also been discussed herein. Overall, this review could provide valuable information to design rules and regulations for the safe disposal of Cu-based NPs into a sustainable environment.


Assuntos
Cobre , Poluentes Ambientais , Nanopartículas Metálicas , Animais , Cadeia Alimentar , Oligoquetos , Solo
11.
Molecules ; 24(22)2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31739645

RESUMO

Trace elements play an important role in the pathogenesis of several serious ophthalmological disorders, such as glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, cataract, etc. This study aimed to measure alterations of chemical elements' (67) levels in the aqueous humor of patients undergoing cataract surgery. The pilot study included 115 patients, (age 74 ± 7.27, female 64.35%, male 35.65%). The aqueous levels of elements were measured by the use of the inductively coupled plasma optical emission spectrometry (ICP-OES), quality controlled with certified standards. The classification of elements based on their concentration was achieved by hierarchical cluster analysis. This is the first screening study that quantifies over 60 elements which are present in the fluid from the anterior chamber of the eye of cataract patients. The obtained results can be suitable for understanding and identifying the causes that may play a role in the initiation and progression of lens opacity.


Assuntos
Humor Aquoso/química , Catarata/metabolismo , Oligoelementos/análise , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Projetos Piloto
12.
Molecules ; 24(20)2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31640293

RESUMO

The aim of the study was to estimate the thiocyanate levels in saliva of cigarette smokers in comparison to e-cigarette smokers and nonsmokers. To improve our understanding of the influence of smoking on the oral level of thiocyanate, we conducted an assessment of human saliva, in 24 individuals (eight tobacco smokers, eight e-cigarette smokers, and eight nonsmokers). High-Performance Liquid Chromatography with ultraviolet detection (HPLC-UV) using a unique phosphatidylcholine column was applied in this assay. Thiocyanate ion was detected directly by its absorbance at 210 nm. The method presents a new application of the IAM (Immobilized Artificial Membrane) column for quantification of inorganic anions. The whole process meets the criteria of green chemistry because it was carried out without the use of organic solvents. For compensating matrix effects, an eight-point standard addition protocol was used to quantify the thiocyanate level in saliva samples. The calibration graphs were linear in the range of 5-100 mg L-1 with a correlation coefficient higher than 0.99. The thiocyanate concentrations in the saliva of tobacco smokers, e-cigarette smokers, and nonsmokers were found in the range of 121.25-187.54 mg L-1, 121.24-244.11 mg L-1, 33.03-79.49 mg L-1, respectively. The present study indicates an obvious statistically significant elevation in salivary thiocyanate level in tobacco smokers in comparison to nonsmokers. The phosphatidylcholine-based stationary phase proved to be suitable for the detection and quantification of the thiocyanate ion. The salivary thiocyanate levels in e-cigarette smokers were not significantly different in comparison to tobacco smokers but higher if compared to nonsmokers. The criterion for statistical significance was p < 0.05.


Assuntos
Saliva/química , Tiocianatos/análise , Fumar Tabaco/efeitos adversos , Adulto , Cromatografia Líquida de Alta Pressão , Sistemas Eletrônicos de Liberação de Nicotina , Química Verde , Humanos , Pessoa de Meia-Idade , Fosfatidilcolinas/química
13.
J Sep Sci ; 42(16): 2628-2639, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31168923

RESUMO

Liquid chromatography coupled to spectrophotometric detection of new antiepileptic compounds, 1,2,4-triazole-3-thione derivatives, on immobilized artificial membrane phosphatidylcholine is reported. The curves representing the relationship between ln k versus 1/T generated under isocratic conditions by the use of methanol and acetonitrile-containing eluent systems have been constructed in order to determine the thermodynamic parameters: the enthalpies, entropies and the relative free energies. The hydrocarbon chains of analytes significantly influenced the membrane behavior of the whole molecules. Excellent correlations of the theoretical lipophilicity with the experimental thermodynamic descriptors, have confirmed contribution of the hydrophobic interactions in the retention process. However, presence of sulfur or oxygen as heteroatoms at R1 substituents in the 1,2,4-triazole ring appears to be responsible for more pronounced selectivity of these compounds on the phosphatidylcholine stationary phase. Molecular dynamics simulations revealed the selective preferences of the phosphatidylcholine with respect to the compounds with either ether of sulfide moieties. Experimental and theoretical set-ups resulted in corresponding outcomes.


Assuntos
Materiais Biomiméticos/química , Varredura Diferencial de Calorimetria , Fosfatidilcolinas/química , Termodinâmica , Tionas/análise , Triazóis/análise , Cromatografia Líquida , Estrutura Molecular , Espectrofotometria
14.
Molecules ; 24(9)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31058813

RESUMO

INTRODUCTION: Alcohol overuse may be related to increased aluminum (Al) exposure, the brain accumulation of which contributes to dementia. However, some reports indicate that silicon (Si) may have a protective role over Al-induced toxicity. Still, no study has ever explored the brain content of Al and Si in alcoholic use disorder (AUD). MATERIALS AND METHODS: To fill this gap, the present study employed inductively coupled plasma optical emission spectrometry to investigate levels of Al and Si in 10 brain regions and in the liver of AUD patients (n = 31) and control (n = 32) post-mortem. RESULTS: Al content was detected only in AUD patients at mean ± SD total brain content of 1.59 ± 1.19 mg/kg, with the highest levels in the thalamus (4.05 ± 12.7 mg/kg, FTH), inferior longitudinal fasciculus (3.48 ± 9.67 mg/kg, ILF), insula (2.41 ± 4.10 mg/kg) and superior longitudinal fasciculus (1.08 ± 2.30 mg/kg). Si content displayed no difference between AUD and control, except for FTH. Positive inter-region correlations between the content of both elements were identified in the cingulate cortex, hippocampus, and ILF. CONCLUSIONS: The findings of this study suggest that AUD patients may potentially be prone to Al-induced neurodegeneration in their brain-although this hypothesis requires further exploration.


Assuntos
Alcoolismo/complicações , Alumínio/análise , Química Encefálica , Doenças Neurodegenerativas/diagnóstico , Silício/análise , Adulto , Idoso , Alumínio/toxicidade , Autopsia , Estudos de Casos e Controles , Córtex Cerebral/química , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Neurodegenerativas/induzido quimicamente , Espectrofotometria Atômica , Tálamo/química
15.
Molecules ; 24(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064131

RESUMO

The aim of this research was to optimize the separation and quantitative determination of nitrites and nitrates in human saliva. HPLC with UV absorption (HPLC/DAD) using a phosphatidylcholine column (IAM.PC.DD2 Regis HPLC) was applied in this assay. Nitrates were detected directly by their absorbance at 210 nm, whereas nitrites were detected after oxidation to nitrates by potassium permanganate at acidic conditions. The kinetics of the permanganate-nitrite reaction was measured chromatographically. The calibration graph for nitrates was linear in the range of 0.5-35 µg mL-1 with a correlation coefficient of 0.9999. The limit of detection was 4.56 ng mL-1. The calibration graph for nitrites (after oxidation to nitrates) was linear in the range of 0.5-15 µg mL-1 with a correlation coefficient of 0.9972. The limit of detection was 4.21 ng mL-1. The nitrate concentrations in the saliva samples were found in the range of 8.98-18.52 µg mL-1, whereas nitrite was in the range of 3.50-5.34 µg mL-1.


Assuntos
Nitratos/análise , Nitritos/análise , Fosfatidilcolinas/química , Saliva/química , Bioensaio/métodos , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia por Troca Iônica/métodos , Humanos , Limite de Detecção , Oxirredução , Permanganato de Potássio/química , Reprodutibilidade dos Testes
16.
Molecules ; 24(7)2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30934973

RESUMO

Iodine is an essential nutrient necessary for the production of thyroid hormones. A valuable source of iodide, which is the bio-available iodine form could be mineral waters offered by different spas. In this work, the method capable of direct determination of iodide in mineral water samples based on IAM liquid chromatography on the phosphatidylcholine column (IAM.PC.DD2 Regis HPLC) with DAD detection without sample pretreatment or any pre-concentration steps is presented. The calibration graph for iodide was linear in the range of 0.5⁻10.0 mg L-1 with a correlation coefficient of 0.9996. The limit of detection was 22.84 ng mL-1. The relative recoveries were in the interval of 98.5⁻100.2% and the repeatability, expressed as a relative standard deviation (RSD) was less than 5%. The RSA (Response Surface Analysis) investigated the effect of the sample concentration and the injection volume. The iodide concentrations in the mineral water samples ranged from 0.58 to 2.88 mg L-1. The accuracy of the method was assessed through independent analysis by ICP-MS. Iodide levels measured by these two procedures did not significantly differ. The effects of interfering ions like HCO3-, Cl-, SO42-, F-, and Br- were also tested. The analysis has shown insignificant differences in the values of the iodide peak area and its height measured in multicomponent mixtures with an error smaller than 5%.


Assuntos
Cromatografia Líquida de Alta Pressão , Iodetos/análise , Águas Minerais/análise , Fosfatidilcolinas/química , Ânions/química , Íons , Controle de Qualidade , Reprodutibilidade dos Testes
17.
Front Chem ; 7: 115, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30891444

RESUMO

Trace elements play a crucial role in many biochemical processes, mainly as components of vitamins and enzymes. Although small amounts of metal ions have protective properties, excess metal levels result in oxidative injury, which is why metal ion homeostasis is crucial for the proper functioning of the brain. The changes of their level in the brain have been proven to be a risk factor for Alzheimer's, Parkinson's, and Huntington's diseases, as well as amyotrophic lateral sclerosis. Therefore, it is currently an important application of various analytical methods. This review covers the most important of them: inductively coupled ground mass spectrometry (ICP-MS), flame-induced atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (GFAAS), optical emission spectrometry with excitation in inductively coupled plasma (ICP-OES), X-ray fluorescence spectrometry (XRF), and neutron activation analysis (NAA). Additionally, we present a summary of concentration values found by different research groups.

18.
Molecules ; 23(11)2018 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-30453653

RESUMO

Tryptophan (TRP) is to an essential amino acid and its catabolites are significant to human health. By using ultra-high-performance liquid chromatography coupled to electrospray ionization triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS), levels of three major components of kynurenic pathway namely tryptophan (TRP), kynurenic acid (KYNA) and kynurenine (KYN) in fluid from the anterior chamber of the eye were determined. The analysis was carried out on a Synergi 4 µ Fusion-RP column using gradient elution mode. For quantitative determination, l-tryptophan-amino-15N, 99 ATOM % 15N was used as an internal standard. The method was linear in the concentration range 4⁻2000 ng mL-1 for TRP, KYNA and KYN. The mean recoveries measured at four concentration levels for TRP, KYN and KYNA included the following ranges 94.3⁻96.1; 91.0⁻95.0; and 96.0⁻97.6%, respectively. The intra-day precision parameters were smaller than 4.4, 6.4 and 5% respectively. The developed method was applied to study the level of TRP, KYNA and KYN in eye fluid for the retrospective case series which included 28 patients suffering from cataracts and diabetes (n = 8). The experimental data was subjected to statistical analysis. The Mann-Whitney U-test revealed clear differences in the level of TRP catabolites and the ratios of TRP/KYN representing the activities of specific enzyme of kynurenine pathway in examined groups of patients. A level of probability p < 0.05 was used throughout a paper to denote statistically significant differences between the groups.


Assuntos
Câmara Anterior/metabolismo , Catarata/metabolismo , Diabetes Mellitus/metabolismo , Triptofano/química , Triptofano/metabolismo , Cromatografia Líquida , Cinurenina/metabolismo , Redes e Vias Metabólicas , Espectrometria de Massas em Tandem
19.
J Sep Sci ; 41(15): 3129-3142, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29897661

RESUMO

Spinacia oleracea L. extract was immobilized on an octadecyl-bonded silica surface to produce a new sorbent for the solid-phase extraction of trace amounts of metal ions from aqueous neutral samples. A measurement of the metal content has been performed by using graphite furnace atomic absorption spectroscopy. The affinity of the investigated bivalent metal cations for the modified sorbent are in the order: Pb(II) > Cu(II) > Ni(II) > Zn(II) ≈ Cd(II) ≈ Co(II). The quantum-chemically calculated chlorophyll-a-metal ion binding energies were consistent with the measured affinities of the corresponding metal ions to the investigated sorbent. The maximum sorption capacity obtained for Pb(II) was equal to 1.44 µmol/g. The value of lead uptake was significantly higher in comparison to the one reported for other sorbents and biosorbents. Immobilized chlorophyll a is responsible for a chelation process with stoichiometry 1:1 owing to the porphyrin rings, which was confirmed by the quantitative analysis performed by reversed-phase high-performance liquid chromatography with diode array detection. The Toth adsorption isotherm model was applicable to the description of the adsorption process of either chlorophyll a or Pb(II). The structural analysis of sorbent was done using Fourier-transform Raman spectroscopy and scanning electron microscopy with an energy dispersive X-ray detector.


Assuntos
Chumbo/isolamento & purificação , Pigmentos Biológicos/química , Dióxido de Silício/química , Extração em Fase Sólida , Spinacia oleracea/química , Poluentes Químicos da Água/química , Chumbo/química , Processos Fotoquímicos , Fotossíntese , Pigmentos Biológicos/síntese química
20.
Artigo em Inglês | MEDLINE | ID: mdl-29100761

RESUMO

The new sorbent for solid phase extraction (SPE), based on silica gel modified with a copper (II), was obtained and its application for phospholipids removal from the human plasma was tested. SPE column conditioning requirements, the volume of the plasma, the composition of the elution solvent were all established. The efficacy of the removal of phospholipids was compared for different methods such as standard protein precipitation or HybridSPE Phospholipid Ultra and HybridSPE-PPT. The sample clean-up was verified by mass spectrometry (MS) and by monitoring of chromatograms in the region between 190nm and 400nm. The Fourier Transform Infrared Spectroscopy FT-IR and confocal Raman microscopy were used to evaluating the silica gel modifications and to show the structure of lipids confined in the silica pores.


Assuntos
Fosfolipídeos/sangue , Fosfolipídeos/isolamento & purificação , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão , Cobre/química , Humanos , Espectrometria de Massas , Sílica Gel/química
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