Search Results (15)

Acid mine drainage (AMD) is the result of the oxidation of pyrite and other sulfide ores, and the catalytic action of microorganisms accelerates the generation of AMD. In this paper, the interaction between 2-mercaptobenzimidazole (MBI) and pyrite in the presence of Acidithiobacillus ferrooxidans (At. ferrooxidans) was studied. The results of leaching experiments showed that when the dosage of MBI was more than or equal to 6 g/kg, the oxidation of pyrite was obviously inhibited, and the inhibition rate of 9 g/kg MBI was the best, reaching 97.1%. Electrochemical tests show that when the amount of MBI exceeds 16.8 mg, the pyrite surface treated with MBI will show good oxidation corrosion resistance, and the corrosion resistance will be enhanced with the increase in MBI dosage. Subsequently, the influence of MBI on bacterial growth was ruled out by experiments, and the surface of passivated pyrite was observed and characterized. The results showed that MBI could chelate with iron on the surface of pyrite through -C=N and -SH in the molecule, which enhanced the hydrophobicity of pyrite, thus reducing the contact between pyrite and the external environment and effectively inhibiting the oxidation of pyrite. Full article

Cobalt electrochemical deposition, with its bottom–up growth properties, is a core technology for creating metal interconnects. Additives are crucial during electrodeposition to control the quality of deposits by adsorbing onto the Co surface. The functional groups of additive molecules are the key to tailoring the adsorption behavior. This study focuses on heteroaromatic thiol additives, including 2-mercaptobenzimidazole (MBI), 2-mercapto-5-benzimidazolesulfonic acid sodium salt dehydrate (MBIS), and 2-mercaptobenzoxazole (MBO). Cyclic voltammetry, chronopotentiometry, quantum chemical calculations, and characterization tests were employed to investigate the adsorption behavior of additive molecules with different functional groups on cobalt. The results indicate that the inhibitory strength of the three additives on electrodeposition follows the following order: MBI > MBIS > MBO. The strong inhibitory effect of MBI primarily stems from the adsorption of the thiol group, the pyridine-like nitrogen in the heterocycle, and the benzene ring. MBIS exhibits reduced inhibitory capability due to the combined effects of the sulfonic acid group and hydrolysis ionization. MBO, with the introduction of an oxygen atom in the heterocycle, shows the weakest adsorption and inhibitory capability among the three. Full article

Τhyreostats (TSs) are veterinary drugs used in livestock farming for fattening. Their administration is banned in the European Union since 1981, and their monitoring for food quality and safety control requires sensitive and confirmatory methods. The present study describes the development and validation of a hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) method for the simultaneous determination of 2-thiouracil (TU), 6-methyl-2-thiouracil (MTU), 6-propyl-2-thiouracil (PTU), 6-phenyl-2-thiouracil (PhTU), tapazole (TAP), and 2-mercaptobenzimidazole (MBI) in bovine muscle tissues. Investigation of the retention mechanism of the six analytes on the selected amide-based stationary phase showed that hydrophilic partition was the dominant interaction. The sample preparation included extraction with ACN/H₂O (80/20), followed by dispersive solid-phase extraction (d-SPE) with C18 sorbent and hexane partitioning. The method was validated according to European guidelines using internal standards, including isotopically labelled ones. The method’s LODs ranged between 2.8 ng g⁻¹ (6-phenyl-2-thiouracil) and 4.1 ng g⁻¹ (2-thiouracil). Application of the proposed method to 48 bovine tissue samples showed non-detectable results. Full article

Tetrahedral copper(I) clusters [Cu₄(MBIZ)₄(PPh₃)₂] (2), [Cu₄(MBOZ)₄(PPh₃)₄] (6) (MBIZ = 2-mercaptobenzimidazole, MBOZ = 2-mercaptobenzoxazole) were prepared by regulation of the copper-thiolate clusters [Cu₆(MBIZ)₆] (1) and [Cu₈(MBOZ)₈I]⁻ (5) with PPh₃. With the presence of iodide anion, the regulation provided the iodide-containing clusters [Cu^I₄(MBIZ)₃(PPh₃)₃I] (3) and [Cu^I₄(MBOZ)₃(PPh₃)₃I] (7). The cyclic voltammogram of 3 in MeCN (0.1 M ⁿBu₄NPF₆, 298 K) at a scan rate of 100 mV s⁻¹ shows two oxidation processes at E_p^a = +0.11 and +0.45 V with return waves observed at E_p^c = +0.25 V (vs. Fc⁺/Fc). Complex 3 has a higher capability to lose and gain electrons in the redox processes than complexes 2, 4, 4′, 6, and 7. Its thermal stability was confirmed by thermogravimetric analysis. The catalytic performance of 3 was demonstrated by the catalytic transformation of iodobenzenes to benzonitriles using AIBN as the cyanide source. The nitrile products show potential applications in the preparation of 1,3,5-triazine compounds for organic fluorescence materials. Full article

Ten 2-mercaptobenzimidazole (2-MBI) analogs were synthesized as potential tyrosinase inhibitors because mercapto-containing compounds can bind to copper ions at the active site of tyrosinase to inhibit enzyme activity. Nine 2-MBI analogs showed sub-micromolar IC₅₀ values for mushroom tyrosinase monophenolase activity; analog 4 was 280-fold more potent than kojic acid, and in diphenolase activity, 6 was 970-fold more potent than kojic acid. The inhibition mode of the 2-MBI analogs was investigated using kinetic studies supported by docking simulations. Benzimidazoles without the 2-mercapto substituent of the 2-MBI analogs lost their tyrosinase inhibitory activity, implying that the 2-mercapto substituent plays an important role in tyrosinase inhibition. The 2-MBI analogs exerted potent antioxidant effects against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and reactive oxygen species (ROS). The results obtained from apple slices and human embryonic kidney cells (HEK-293) suggest that most 2-MBI analogs are sufficiently safe candidates to delay the browning of apple slices effectively. Thus, these results support the potential use of 2-MBI analogs as anti-browning agents in foods such as mushrooms, vegetables, and fruits. Full article

In this paper, a 2-mercaptobenzimidazole-copper nanoparticles (MBI-CuNPs) fluorescent probe with high performance based on 2-mercaptobenzimidazole functionalized copper nanoparticles was synthesized by a hydrothermal method and used for cysteine (Cys) detection in serum. The MBI-CuNPs probe exhibits strong fluorescence emission at 415 nm under the excitation at 200 nm, which is attributed to the metal-ligand charge transfer (MLCT) transition through the coordination of an MBI ligand and monovalent copper. Furthermore, the MBI-CuNPs probe has a high quenching fluorescence response to Cys, and shows a good linearity relationship with Cys in 0.05–65 µM, with a detection limit of 52 nM. Moreover, the MBI-CuNPs probe could eliminate the interference of biological mercaptan Hcy and GSH with a similar structure and reaction properties, due to the strong electron-donating ability of Cys, which can quench the fluorescence of the MBI-CuNPs probe. The MBI-CuNPs probe was applied to the analysis of Cys in real serum, and the absolute recovery rate was as high as 90.23–97.00%. Such a fluorescent probe with high sensitivity and selectivity has potential applications for the early prevention of various diseases caused by abnormal Cys levels. Full article

The ability of NQO2 to increase the production of free radicals under enhanced generation of quinone derivatives of catecholamines is considered to be a component of neurodegenerative disease pathogenesis. The present study aimed to investigate the neuroprotective mechanisms of original NQO2 inhibitor M-11 (2-[2-(3-oxomorpholin-4-il)-ethylthio]-5-ethoxybenzimidazole hydrochloride) in a cellular damage model using NQO2 endogenous substrate adrenochrome (125 µM) and co-substrate BNAH (100 µM). The effects of M-11 (10–100 µM) on the reactive oxygen species (ROS) generation, apoptosis and lesion of nuclear DNA were evaluated using flow cytometry and single-cell gel electrophoresis assay (comet assay). Results were compared with S29434, the reference inhibitor of NQO2. It was found that treatment of HT-22 cells with M-11 results in a decline of ROS production triggered by incubation of cells with NQO2 substrate and co-substrate. Pre-incubation of HT-22 cells with compounds M-11 or S29434 results in a decrease of DNA damage and late apoptotic cell percentage reduction. The obtained results provide a rationale for further development of the M-11 compound as a potential neuroprotective agent. Full article

Original results are presented in the field of research that addresses the extension of the reaction of residue of acyl-thiosemicarbazide fixation on the structure of 5-nitrobenzimidazole by a sulphonic group. The aim of the study is the increase of new thiosemicarbazide derivatives’ applicative potential in the field of biochemistry, with a wide range of medical applications. The newly obtained compounds were characterized by using elemental analysis and spectral analysis (FT-IR and ¹H NMR). A study regarding the optimization of the chemical reactions was made. The performed in vitro biological tests confirmed the tuberculostatic activity of three newly obtained compounds against Mycobacterium tuberculosis. Full article

The plant hormone indole-3-acetic acid (IAA) is one of the main signals playing a role in the communication between host and endophytes. Endophytes can synthesize IAA de novo to influence the IAA homeostasis in plants. Although much is known about IAA biosynthesis in microorganisms, there is still less known about the pathway by which IAA is synthesized in fungal endophytes. The aim of this study is to examine a possible IAA biosynthesis pathway in Cyanodermella asteris. In vitro cultures of C. asteris were incubated with the IAA precursors tryptophan (Trp) and indole, as well as possible intermediates, and they were additionally treated with IAA biosynthesis inhibitors (2-mercaptobenzimidazole and yucasin DF) to elucidate possible IAA biosynthesis pathways. It was shown that (a) C. asteris synthesized IAA without adding precursors; (b) indole-3-acetonitrile (IAN), indole-3-acetamide (IAM), and indole-3-acetaldehyde (IAD) increased IAA biosynthesis; and (c) C. asteris synthesized IAA also by a Trp-independent pathway. Together with the genome information of C. asteris, the possible IAA biosynthesis pathways found can improve the understanding of IAA biosynthesis in fungal endophytes. The uptake of fungal IAA into Arabidopsis thaliana is necessary for the induction of lateral roots and other fungus-related growth phenotypes, since the application of the influx inhibitor 2-naphthoxyacetic acid (NOA) but not the efflux inhibitor N-1-naphtylphthalamic acid (NPA) were altering these parameters. In addition, the root phenotype of the mutation in an influx carrier, aux1, was partially rescued by C. asteris. Full article

Methylmercury (MeHg⁺) is a mercury species that is very toxic for humans, and its monitoring and sorption from environmental samples of water are a public health concern. In this work, a combination of theory and experiment was used to rationally synthesize an ion-imprinted polymer (IIP) with the aim of the extraction of MeHg⁺ from samples of water. Interactions among MeHg⁺ and possible reaction components in the pre-polymerization stage were studied by computational simulation using density functional theory. Accordingly, 2-mercaptobenzimidazole (MBI) and 2-mercaptobenzothiazole (MBT), acrylic acid (AA) and ethanol were predicted as excellent sulfhydryl ligands, a functional monomer and porogenic solvent, respectively. Characterization studies by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) revealed the obtention of porous materials with specific surface areas of 11 m² g⁻¹ (IIP–MBI–AA) and 5.3 m² g⁻¹ (IIP–MBT–AA). Under optimized conditions, the maximum adsorption capacities were 157 µg g⁻¹ (for IIP–MBI–AA) and 457 µg g⁻¹ (for IIP–MBT–AA). The IIP–MBT–AA was selected for further experiments and application, and the selectivity coefficients were MeHg⁺/Hg²⁺ (0.86), MeHg⁺/Cd²⁺ (260), MeHg⁺/Pb²⁺ (288) and MeHg⁺/Zn²⁺ (1510), highlighting the material’s high affinity for MeHg⁺. The IIP was successfully applied to the sorption of MeHg⁺ in river and tap water samples at environmentally relevant concentrations. Full article

Giardiasis is a diarrheal disease that is highly prevalent in developing countries. Several drugs are available for the treatment of this parasitosis; however, failures in drug therapy are common, and have adverse effects and increased resistance of the parasite to the drug, generating the need to find new alternative treatments. In this study, we synthesized a series of 2-mercaptobenzimidazoles that are derivatives of omeprazole, and the chemical structures were confirmed through mass, ¹H NMR, and ¹³C NMR techniques. The in vitro efficacy compounds against Giardia, as well as its effect on the inhibition of triosephosphate isomerase (TPI) recombinant, were investigated, the inactivation assays were performed with 0.2 mg/mL of the enzyme incubating for 2 h at 37 °C in TE buffer, pH 7.4 with increasing concentrations of the compounds. Among the target compounds, H-BZM2, O₂N-BZM7, and O₂N-BZM9 had greater antigiardial activity (IC₅₀: 36, 14, and 17 µM on trophozoites), and inhibited the TPI enzyme (K₂: 2.3, 3.2, and 2.8 M⁻¹ s⁻¹) respectively, loading alterations on the secondary structure, global stability, and tertiary structure of the TPI protein. Finally, we demonstrated that it had low toxicity on Caco-2 and HT29 cells. This finding makes it an attractive potential starting point for new antigiardial drugs. Full article

This research aimed to develop a better understanding of the corrosion inhibition of the mild steel in acidic medium by new organic molecules. For this purpose, two new compounds namely, 2,3-dihydrobenzo[4,5]imidazo[2,1-b]thiazole (2-BIT) and 3,4-dihydro-2H-benzo[4,5]imidazo[2,1-b]thiazole (3-BIT) were synthesized and evaluated for mild steel (MS) corrosion in HCl. Analyses were carried out using weight loss measurements, electrochemical techniques, and scanning electron microscope (SEM). The adsorption of inhibitors onto the steel surface follows the Langmuir adsorption model. Generally, results showed that the corrosion inhibition efficiency of the investigated molecules was found to increase with increased concentration of inhibitors. Electrochemical tests, i.e., electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques, showed that the addition of our investigated inhibitors decreases the dissolution of the metal and generally act as mixed-type inhibitors. In addition, the influence of temperature (from 303 to 333 K) on the corrosion inhibition was studied, and the results demonstrated that with an increase in temperature, the inhibition efficiency decrease. SEM results confirmed that the inhibition process is due to a protective film that prevents corrosion. Similarly, the results showed that the inhibitory efficiencies reach 93% at 5 × 10⁻³ M in the case of inhibitor 3-BIT. These results revealed that this compound could effectively control and reduce the corrosion rate of mild steel in the corrosion test solution. Full article

A series of novel pleuromutilin derivatives with substituted benzimidazole moieties were designed and synthesized from pleuromutilin and 5-amino-2-mercaptobenzimidazole through sequential reactions. All the newly synthesized compounds were characterized by IR, NMR, and HRMS. Each of the derivatives was evaluated in vitro for their antibacterial activity against Escherichia coli (E. coli) and five Gram (+) inoculums. 14-O-((5-amino-benzimidazole-2-yl) thioacetyl) mutilin (3) was the most active compound and showed highest antibacterial activities. Furthermore, we evaluated the inhibition activities of compound 3 on short-term S. aureus and MRSA growth and cytochrome P450 (CYP). The bioassay results indicate that compound 3 could be considered potential antibacterial agents but with intermediate inhibition of CYP3A4. Full article