Thiol Research Articles

Phytogenic-Mediated Zinc Oxide Nanoparticles Using the Seed Extract of Citrullus lanatus and Its Integrated Potency against Multidrug Resistant Bacteria.

In the current research study, zinc oxide nanoparticles (ZnO-NPs) were synthesized via a green synthesis technique using the seed extract of Citrullus lanatus. The study further intended to evaluate the potential synergistic effects of ZnO-NPs with antibiotics against multidrug resistant (MDR) bacteria. It was observed that C. lanatus seed extracts obtained by n-hexane and methanolic solvents revealed the presence of constituents, such as tannins, flavonoids, and terpenoids. Furthermore, the extract of n-hexane displayed the strongest antibacterial activity against Yersinia species (17 ± 1.2 mm) and Escherichia coli (17 ± 2.6 mm), while the methanolic extract showed the maximum antibacterial activity against E. coli (17 ± 0.8 mm). Additionally, the ZnO-NP synthesis was confirmed by ultraviolet-visible analysis with a characteristic absorption peak at 280 nm. The Fourier transform infrared spectroscopy analysis suggested the absorption peaks in the 500-3800 cm-1 range, which corresponds to various groups of tertiary alcohol, aldehyde, amine, ester, aromatic compounds, thiol, amine salt, and primary amine. The scanning electron microscopy spectra of ZnO-NPs demonstrated the presence of zero-dimensional spherical particles with well-dispersed character. Moreover, encapsulation with ZnO-NPs improved the antimicrobial activity of antibiotics against the panel of MDR bacteria, and the increases in the effectiveness of particular antibiotics against MDR bacteria were significant (P = 0.0005). In essence, the synthesized ZnO-NPs have the potential as drug carriers with powerful bactericidal properties that work against MDR bacterial strains. These outcomes are an indication of such significance in pharmaceutical science, giving possibilities for further research and development in this field.

First Evidence of Gastroprotection by Schinus molle: Roles of Nitric Oxide, Prostaglandins, and Sulfhydryls Groups in Its Mechanism of Action.

Schinus molle is a plant traditionally used in Mexico to treat gastric disorders. However, no scientific evidence has been reported on its gastroprotective effect. The aim of the current contribution was to conduct a bioassay-guided study on S. molle to evaluate its gastroprotective activity in a model of Wistar rats given ethanol orally to induce gastric lesions. The hexane and dichloromethane extracts from the tested plant showed over 99% gastroprotection at a dose of 100 mg/kg. From the hexane extract, two of the three fractions (F1 and F2) afforded over 99% gastroprotection. The F1 fraction was subjected to column chromatography, which revealed a white solid. Based on the ESI-MS analysis, the two main compounds in this solid were identified. The predominant compound was probably a triterpene. This mixture of compounds furnished about 67% gastroprotection at a dose of 100 mg/kg. Pretreatment with L-NAME, indomethacin, and NEM was carried out to explore the possible involvement of nitric oxide, prostaglandins, and/or sulfhydryl groups, respectively, in the gastroprotective activity of the white solid. We found evidence for the participation of all three factors. No antisecretory activity was detected (tested by pylorus ligation). In conclusion, evidence is herein provided for the first time of the gastroprotective effect of S. molle.

Cu-CDs as dual optical and electrochemical nanosensor for βME detection

Thiols play critical roles in biological processes. Here, a facile hydrothermal synthesis approach was used for fabrication of flourescent Cu-carbon dots (Cu-CDs), to be employed as accurate thiol Nanosensors. The obtained Cu-CDs were characterized using transmission electron microscopy, UV–visible, photoluminescence and X-ray photoelectron spectroscopy scannings. The highest-occupied- and lowest-unoccupied- molecular-orbitals and the pertaining energy band gap were achieved using analytical chemistry density functional theory. Electrochemical performance of Cu-CDs showed the capability of the fabricred nanoparticles for accurate, sensitive, and selective nanosensing of thiols, as both electrochemical and optical detection tools. The electrochemical peak of Cu-CDs were selectively, rationally and intensively suppressed by thiols, due to the strong electrostatic interaction and covalent bonding between the NH2 functional groups of the Cu-CDs and -SH groups of thiols. On the other hand, the blue photoluminescence emission of Cu-CDs rationally increased, due to detachment of Cu ions from the edges of Cu-CDs in the existance of thiols. According to the above description, the limit of detections (LODs) of 1 nM was achieved, introducing such-prepared Cu-CDs nanosensors, as simple, fast, low-cost, sensitive and selective tools for thiol detection.

Accelerated lipid peroxidation in a rat model of gentamicin nephrotoxicity.

Kidney disease represents a burden for the health care system worldwide. As the prevalence continues to rise, discovering new biomarkers of early kidney damage has become crucial. Oxidative stress (OS) represents one of the main factors involved in the early stages of many syndromes leading to kidney damage. Therefore, it must be studied in detail. To date, many studies have focused on OS in advanced stages of acute kidney injury (AKI), with great success. The aim of the present study was to ascertain whether even mild renal function impairment can be linked to specific systemic markers of OS and systemic antioxidants in order to pinpoint certain biomarkers for early kidney damage. We used male rats (Rattus norvegicus) in which we induced kidney damage by injecting gentamicin for 7 days. Blood was collected 24 h after the last dose of gentamicin. Urea, creatinine, 3-nitrotyrosine (3-NT), nitric oxide (NO), malondialdehyde (MDA), thiols (TS), total oxidative stress (TOS), and interferon-γ (IFN-γ) were determined. In addition, for the antioxidant status we measured total antioxidant capacity (TAC) and interleukin-10 (IL-10). Our results demonstrated that the rats had mild renal impairment consistent with a pre-AKI stage due to the nephrotoxic effect of gentamicin. However, TOS, MDA and NO were significantly higher in the gentamicin group compared to the control group. In addition, TAC was higher in the control group. Hence, OS markers reach higher levels and may potentially be used as markers of kidney damage even in cases of mild renal function impairment.

Inhibition of angiotensin II type 1 receptor by candesartan reduces tumor growth and ameliorates fibrosis in colorectal cancer.

Colorectal cancer (CRC) is an important cause of cancer-related mortality. Aberrant activation of the renin-angiotensin system (RAS) is reported to be associated with poor clinical outcomes in patients with CRC. This study was designed to explore the anti-tumor effects of the angiotensin receptor blocker Candesartan either alone or in combination with 5-FU in in vitro and in vivo models of CRC. The cytotoxic effects of Candesartan were assessed using the MTT assay in two colorectal cancer cell lines (CT-26 and SW-480). To investigate the potential regulatory role of Candesartan on tumor growth, apoptosis, and migration, the expression levels of Cyclin D1, Survivin, MMP3, MMP9, and E-cadherin mRNAs were evaluated. The oxidant/antioxidant balance was also examined by determining the levels of MDA, thiols, SOD, and CAT. We used a xenograft model of colon cancer to investigate the effects of Candesartan alone, or in combination with 5-FU, on tumor growth following histological staining (Hematoxylin & Eosin and Masson trichrome staining) and biochemical studies as well as gene expression analyses by RT-PCR and western blotting. Candesartan suppressed tumor cell proliferation and migration by modulating Cyclin D1, MMP3/9, and E-cadherin. Treatment with Candesartan either alone, or in combination with 5-FU decreased tumor size in the mouse model, and also increased the level of oxidative markers MDA and reduced CAT, SOD, and thiols. Histological evaluation showed that Candesartan increased tumor necrosis, reduced tumor density and attenuated collagen deposition reducing tumor fibrosis in tumor xenograft. Candesartan, an inhibitor of the RAS, when used in combination with 5-FU reduced tumor growth by inhibiting fibrosis and inducing ROS production, supporting further clinical studies on this therapeutic approach for treatment of CRC.

A simple fluorescent probe for glutathione detection and its bioimaging application in living cells

This study aimed to develop a simple fluorescent probe for detecting glutathione (GSH) over cysteine (Cys) and homocysteine (Hcy). To this end, two fluorescent probes HPY1, 2 that used pyrazoline as the fluorophore and an acrylate group as the recognition group for thiols were designed and synthesized. HPY1, 2 possessed excellent sensitivity, high selectivity and great stability for detecting GSH. The detection limit of HPY1, 2 for GSH was found to be 2.06 × 10-7 M, 1.36 × 10-7 M respectively. The recognition mechanism of HPY1, 2 to GSH were studied by fluorescence change experiments, HRMS and DFT calculation, which elucidated that HPY1, 2 and GSH could undergo Michael addition reaction to generate strongly fluorescent addition products. Additionally, HPY1 was successfully applied to imaging of both endogenous and exogenous GSH in L929 cells based on its low cytotoxicity and good cell permeability. This wok indicated that HPY1, 2 have a great potential for application in detection of GSH.

Interactions of apocarotenoids with thiol containing compounds

Interactions of apocarotenoids with thiol containing compounds

Influence of the nature of the alkanethiol terminal group on the electrochemical stability and blocking ability of self-assembled nanofilms on Au electrode

We studied the effect of the nature of the terminal group of thiols with the same chain length HS (CH2)8 – R (R: -CH3, -CH2OH, -NH2) on the electrodesorption behaviour of well-formed SAMs (the self-assembled monolayers), their stability and blocking ability using voltammetry and chronoamperometry. The nature of the terminal functional group determines the surface properties of SAM and provides the basis for subsequent interactions (for example, with peptides, proteins, DNA) in order to create sensors and bioagents. For the studied thiols, the hydrophilicity of the end groups increases in the series -CH3<< -NH2 ≤ -CH2OH; they also differ in polarity and the possibility of protonation of the amino group. For thiols with -CH3 and -CH2OH groups, an increase in the hydrophilicity of the terminal group leads to the formation of less stable and less ordered films. The replacement of carbon by nitrogen with approximately the same hydrophilicity of the groups (-CH2OH and -NH2) leads to the formation of a more stable film consisting of molecules in the same energy state, butwith poorer insulatingproperties.

Frontispiece: Remote Fluorination and Fluoroalkyl(thiol)ation Reactions

Frontispiece: Remote Fluorination and Fluoroalkyl(thiol)ation Reactions

Chemically Induced Vinylphosphonothiolate Electrophiles for Thiol–Thiol Bioconjugations

Chemically Induced Vinylphosphonothiolate Electrophiles for Thiol–Thiol Bioconjugations

Iridium-Catalyzed Site-Selective Thiolation

Iridium-Catalyzed Site-Selective Thiolation

Inhibitory effect of alpha-lipoic acid on mitochondrial dysfunction and interleukin-8 expression in interleukin-1beta-stimulated ataxia teleangiectasia fibroblasts.

Ataxia telangiectasia (A-T) is an inherited neurodegenerative disease caused by mutation in the ataxia telangiectasia mutated (ATM) gene, leading to loss of function in the encoded protein ATM. Because ATM functions to reduce oxidative stress by up-regulating antioxidant enzymes, oxidative stress is a prevalent A-T phenotype and a mediator of the inflammation that drives A-T pathology. Reactive oxygen species (ROS) levels and the expression of pro-inflammatory cytokine interleukin-8 (IL-8) were higher in A-T cells than in normal cells. ROS are related to mitochondrial dysfunction and activation of nuclear factor kappa B (NF-κB) to induce IL-8 expression. Alpha-lipoic acid (α-LA), a naturally occurring thiol compound, shows an antioxidant effect in various cells. This study is aimed to determine if α-LA confers protection against NF-κB activation, IL-8 expression, and mitochondrial dysfunction in A-T cells which are exposed to the inflammatory cytokine IL-1β. A-T fibroblasts were treated with or without α-LA. The levels of intracellular and mitochondrial ROS, mRNA and protein levels of IL-8, mitochondrial membrane potential (MMP), ATP levels, and DNA binding activity of NF-κB were determined. As a result, IL-1β increased NF-κB activation, IL-8 expression, intracellular and mitochondrial ROS levels, but decreased MMP and ATP level in A-T cells. Pretreatment of A-T cells with α-LA inhibited IL-1β-induced activation of NF-κB, IL-8 expression, and mitochondrial dysfunction by reducing ROS levels. In conclusion, supplementation with α-LA may be beneficial for reducing the oxidative stress-induced mitochondrial dysfunction and IL-8 production associated with A-T.

Laboratory evaluation of a novel multifunctional chemical solution for asphaltene precipitation and aggregation problem: Comparison with an industrial chemical solution

Asphaltene deposition in the near-wellbore area and within the pipelines reduces productivity and is costly. There are usually 2 methods to remedy this hardship that are using dispersants or inhibitors to preventing asphaltene deposition or using solvents when asphaltene deposits on inner surface of pipes or in the porous media. In this study, additive called AUT Force 110 has been developed and its properties have been inspected. This solvent has multifunctional efficiencies (MS) such that can be used as asphaltene inhibition and dispersion and dissolve asphaltene deposits. Furthermore, its performance is compared to an industrial solvent called PL5001 (CS). Analyzing the fourier-transform infrared spectroscopy (FTIR) of the two additives were found to have polar functional groups of hydroxyl, thiol, carbonyl and carboxylic acid in their molecule. The existence of various functional groups gives the MS molecule the ability to interact with adjacent molecules through hydrogen bonding. In addition, aliphatic compounds were observed in the MS molecule with a low carbon number, which leads to its compatibility with crude oil. In contrast, the CS consists mainly of aromatic rings. Two carbonyl and ether functional groups were also observed in its molecular structure, which are very low in concentration compared to polar compounds of MS. Then, the confocal microscopy imaging was used to observe asphaltene aggregates with precipitant. The crude oil and n-heptane were combined in a ratio of 1–30 volumes. The addition of 100 ppm MS reduced about 87% of the mean diameter of asphaltene aggregates; while this reduction was less than 70% by adding CS. Also, adding MS narrowed the dispersion range of the asphaltene particles diameter to 2–16 μm. The carboxylic acid and thiol functional groups play important roles in asphaltene dispersion in MS system. Both MS and CS delayed the onset of asphaltene precipitation, however MS has greater asphaltene inhibition power as well as improving the rheological properties of crude oil and n-heptane solution due to the reduction in the size of asphaltene aggregates, the interaction of MS with asphaltene, and the reduction of the interaction between the asphaltene-asphaltene molecule besides the polar nature of MS. Turbiscan test was also used to measure the solvation power of two additives. The solubility number of MS was lower than that of CS and was reported to be a good solvent, indicating that it has better solvation power than CS. Because MS has the ability to hydrogen bond with asphaltene molecules as both donor and acceptor. Secondly, its aliphatic chains cause steric hindrance, which contributes to the stability of asphaltenes within MS.

Silver nanoparticles restrict microbial growth by promoting oxidative stress and DNA damage.

Bacterial infections remain a serious health issue; hence there is a need for continuous search for improved antimicrobials. In addition, it is important to understand the antibacterial mechanism of prospective antimicrobials to fully harness their benefits. In this study, the antimicrobial action of silver nanoparticles was investigated. The antimicrobial potential of silver nanoparticles against different strains of bacteria was evaluated after which Escherichia coli and Staphylococcus aureus were selected as model for gram-negative and gram-positive bacteria respectively. Additionally, to determine mechanism of action, some biochemical assays including determination of kynurenine level, DNA fragmentation, lipid peroxidation and antioxidant status were carried out. Results showed that silver nanoparticles caused DNA damage and induced oxidative stress as reflected in elevated nitric oxide production and lipid peroxidation level. In contrast silver nanoparticles increased the antioxidant capacity viz-a-viz, elevated levels of total thiol, superoxide dismutase (SOD), and total antioxidant capacity (TAC) compared to untreated cells. They also initiated inconsistent alteration to the kynurenine pathway. Taken together, the findings indicate that silver nanoparticles exhibited antimicrobial action through the promotion of oxidative stress.

КВАНТОВО-ХИМИЧЕСКОЕ ИЗУЧЕНИЕ МЕХАНИЗМА РЕАКЦИИ 1,2-ЭТАНДИТИОЛА С 1,3-ДИХЛОРПРОПЕНОМ

The theoretical mechanism of the interaction of 1,3-dichloropropene with 1,2-
 ethanedithiol in the system "hydrazine hydrate-KOH" has been proposed by the method of B3LYP / 6-
 311 ++ G (d, p) in the framework of the theory of the electron-density functional according to which the
 reaction proceeds successively in several stages, including the nucleophilic substitution of the chlorine
 atom present in the sp3-hybridized carbon atom with a sulfur atom to form a mono-substitution product
 that undergoes a prototropic allylic rearrangement that migrates the double bond to the sulfur atom,
 followed by closure in the dithiolane cycle due to the nucleophilic attack of the sulfide anion of the
 second thiol group of the reagent per carbon atom located in the γ-position with respect to the second
 chlorine atom.

ТЕОРЕТИЧЕСКОЕ ИЗУЧЕНИЕ МЕХАНИЗМА РЕАКЦИИ 1,2-ЭТАНДИТИОЛА С 1,3-ДИХЛОРПРОПЕНОМ

The theoretical mechanism of the interaction of 1,3-dichloropropene with 1,2-ethanedithiol in the system "hydrazine hydrate-KOH" has been proposed by the method of B3LYP / 6-311 ++ G (d, p) in the framework of the theory of the electron-density functional according to which the reaction proceeds successively in several stages, including the nucleophilic substitution of the chlorine atom present in the sp3-hybridized carbon atom with a sulfur atom to form a mono-substitution product that undergoes a prototropic allylic rearrangement that migrates the double bond to the sulfur atom, followed by closure in the dithiolane cycle due to the nucleophilic attack of the sulfide anion of the second thiol group of the reagent per carbon atom located in the γ-position with respect to the second chlorine atom.

Assessment of biochemical parameters and study its correlation in ß-Thalassemia major patients and healthy controls in Kirkuk City, Iraq

Background: Thalassemia is the name of a group of genetically (acquired) blood diseases, which include defects on the production of hemeprotein, and fractional or complete damage to the combination of a particular sort of simple protein chain. The defect might have an effect on the “α, γ and δ” chains or might have an effect on few combination of the “β, γ and δ” chains within the same patient. Objective: The aim of the study was to evaluate the various protein parts in the s-thalassemia major (BTM) patients in the city of Kirkuk compared to the healthy control group. Materials and Methods: Seventy blood samples were divided into two groups – 45 patients with BTM samples; they visited Azadi Hospital/Kirkuk city and 25 samples of healthy controls as a control group. Results: The results of the correlation coefficient showed that there were significant positive correlation between total protein (TP) and albumin and albumin and albumin/globulin ratio and significant negative correlation between globulin and albumin/globulin ratio. Finally, nonsignificant positive correlation between TP and thiol, TP and globulin, TP and albumin-globulin ratio, albumin/thiol, globulin and free amino and globulin and thiol and non-significant negative correlation between TP and free amino, thiol and carbonyl, thiol and free amino, carbonyl and free amino, albumin and carbonyl, albumin and free amino, albumin and globulin, and globulin and carbonyl. Conclusion: The correlation studies between the above parameters indicated a negative relationship between TP and free amine in β-thalassemia patients. These results reinforce the importance of measuring both TP and free amine concentration to investigate their development of β-thalassemia complications. Also, measuring both thiol and free amine yields is also important for the same reason.

Chemical State Analysis of the Periostracum in the Corbicula Clam Hatched in Lake Biwa

The periostracum of corbicula clams is a unique outermost organic layer secreted from the inner surface of the outer mantle. It records the environmental history of corbicula clams which inhabited Lake Biwa. Two types of corbicula clams, yellowish and blackish shells, were studied with X-ray fluorescence element mapping and S, Fe and Mn K-edge X-ray absorption fine structure (XAFS) spectroscopy. It was revealed that the blackish shells grow in the more reducing environment than the yellowish ones. Main constituent of the periostracum is protein-based material, such as cysteine and methionine. The blackish shells contain much higher amount of Fe and Mn impurities. Fe was accumulated as FeOOH along the growth lines. Sulfur exists exclusively as organic molecules with the functional groups of thiol (-SH), which is oxidized to form disulfide (-SS-) by exposure to the oxidizing environment.

Antioxidative and oxidative profiles in plasma and saliva of cows in different ages and hormonal status.

The aim of this study was to evaluate changes in the antioxidant status and oxidative stress parameters in plasma and saliva in order to investigate the physiological conditions of dairy cows. Blood and saliva were collected from clinically healthy female calves (n = 18), sexually mature, non-pregnant cows (n = 19), and pregnant dairy cows (n = 15). Spectrophotometric and spectroflurimetric analyses were carried out in the body fluids of these animals. The level of total antioxidant capacity (TAC) in plasma reached the lowest (p < 0.05) value in the group of sexually mature, non-pregnant cows (2.375 ± 0.500 μmol/g). A significant negative correlation (tau b = - 0.248, p < 0.05) was found between TAC values detected in plasma and saliva of examined animals. The highest (p < 0.05) mean values of thiol groups were detected in both plasma (0.007 ± 0.0015 mmol/g) and saliva (0.276 ± 0,116 mmol/g) of mature, non‑pregnant cows. Conversely, the highest (p < 0.05) levels of formylokinurenine concentration were detected in saliva (11.535 ± 3.785 μg/mg) and plasma (0.133 ± 0.0237 μg/mg) of pregnant dairy cows. A significant positive correlation (tau b = 0.255, p < 0.05) was also found between the bityrosine content detected in plasma and saliva of the examined cows. In conclusion, although with regards to antioxidant/oxidative parameters saliva reflects the content of plasma only in part, however it shows age-related differences that can be used in the description of the physiological status of cows.

Nanostructured silver dendrites for photon-induced Cysteine dimerization

Under a controlled adsorption environment, L-cysteine molecules can be chemically adsorbed to the dendritic silver (Ag-D) surface by electrochemical methods with different functional groups. It is verified by surface-enhanced Raman spectroscopy that under alkaline conditions (pH = 13.50), the two functional groups of thiol and acid are simultaneously adsorbed on the surface of Ag-D, while NH2 is far from the surface; under acidic conditions (pH = 1.67), adsorption behavior suggests that both NH3+ and COO− are oriented toward the Ag-D surface, and that SH is far from the surface. The structure of L-cysteine adsorption under acidic conditions can be further verified by the addition of an L-cysteine molecule through light-induced coupling reaction to form cystine. Finally, in-situ two-dimensional Raman scattering spectroscopy confirmed the feasibility and uniformity of the coupling reaction.