Antimicrobial activity of some thiourea derivatives and their nickel and copper complexes

The pattern of bifurcated hydrogen bonds in thiourea cocrystals with diazine derivatives: experimental and quantum theoretical studies

Cocrystals of thiourea with pyrazine N-oxide as thiourea-pyrazine N-oxide (2/1), C4H4N2O·2CH4N2S, (I), and with phenazine as thiourea-phenazine (6/7), 7C12H8N2·6CH4N2S, (II), both crystallize in the monoclinic space group P21/c. In the crystalline state, molecules of both components are linked by N-H...N hydrogen bonds. In addition, there are R22(8) hydrogen-bond synthons between thiourea molecules in both crystal structures. Furthermore, bifurcated hydrogen bonds between the -NH groups in the thiourea molecule and the N and O atoms in the N-oxide ring [in (I)], as well as the N atom in the central phenazine ring [in (II)], play a significant role in both structures. This emerging motif was thoroughly examined using quantum chemistry methods.

Medicinal applications of vanadium complexes with Schiff bases

Many transition metal complexes have been explored for their therapeutic properties after the discovery of cisplatin. Schiff bases have an efficient complexation tendency with the transition metals and several medicinal properties have been reported. However, fewer studies have reported the medicinal utility of vanadium and its Schiff base complexes. This paper provides a comprehensive overview of vanadium complexes with Schiff bases along with their mechanistic insight. Vanadium complexes in + 4 and + 5 oxidation states have exhibited well-defined geometry and found to be thermodynamically stable. The studies have reported the G0/G1 phase cell cycle arrest and decreased delta psi m, inducing mitochondrial membrane depolarization in cancer cell lines along with the alterations in the metabolism of the cancer cells upon dosing with the vanadium complexes. Cancer cell invasion and growth are also found to be markedly reduced by peroxo complexes of vanadium. The studies included in the review paper have been taken from leading indexing databases and focus was laid on recent reports in literature. The biological potential of vanadium complexes of Schiff bases opens new horizons for future interdisciplinary studies and investigation focussed on understanding the biochemistry of these complexes, along with designing new complexes which have better bioavailability, solubility and low or non-toxicity.

In Vitro Anti-Microbial Activity and Anti-Cancer Potential of Novel Synthesized Carbamothioyl-Furan-2-Carboxamide Derivatives

A series of carbamothioyl-furan-2-carboxamide derivatives were synthesized using a one-pot strategy. Compounds were obtained in moderate to excellent yields (56-85%). Synthesized derivatives were evaluated for their anti-cancer (HepG2, Huh-7, and MCF-7 human cancer cell lines) and anti-microbial potential. Compound p-tolylcarbamothioyl)furan-2-carboxamide showed the highest anti-cancer activity at a concentration of 20 μg/mL against hepatocellular carcinoma, with a cell viability of 33.29%. All compounds showed significant anti-cancer activity against HepG2, Huh-7, and MCF-7, while indazole and 2,4-dinitrophenyl containing carboxamide derivatives were found to be less potent against all tested cell lines. Results were compared with the standard drug doxorubicin. Carboxamide derivatives possessing 2,4-dinitrophenyl showed significant inhibition against all bacterial and fungal strains with inhibition zones (I.Z) in the range of 9-17 and MICs were found to be 150.7-295 μg/mL. All carboxamide derivatives showed significant anti-fungal activity against all tested fungal strains. Gentamicin was used as the standard drug. The results showed that carbamothioyl-furan-2-carboxamide derivatives could be a potential source of anti-cancer and anti-microbial agents.

New N-acyl Thiourea Derivatives: Synthesis, Standardized Quantification Method and In Vitro Evaluation of Potential Biological Activities

New N-acyl thiourea derivatives with heterocyclic rings have been synthesized by first obtaining isothiocyanate, which further reacted with a heterocyclic amine, characterized by (FT-IR, NMR spectroscopy and FT-ICR) and tested for their in vitro antimicrobial, anti-biofilm and antioxidant activities to obtain a drug candidate in a lead-optimization process. From the tested compounds, those bearing benzothiazole (1b) and 6-methylpyridine (1d) moieties revealed anti-biofilm activity against E. coli ATCC 25922 at MBIC values of 625 µg/mL. Compound 1d exhibited the highest antioxidant capacity (~43%) in the in vitro assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Considering the in vitro results, the highest anti-biofilm and antioxidant activities were obtained for compound 1d. Therefore, a reversed-phase high-performance liquid chromatography (RP-HPLC) method has been optimized and validated for the quantitative determination of compound 1d. The detection and quantitation limits were 0.0174 μg/mL and 0.0521 μg/mL, respectively. The R² correlation coefficient of the LOQ and linearity curves were greater than 0.99, over the concentration range of 0.05 μg/mL-40 μg/mL. The precision and accuracy of the analytical method were within 98-102%, confirming that the method is suitable for the quantitative determination of compound 1d in routine quality control analyses. Evaluating the results, the promising potential of the new N-acyl thiourea derivatives bearing 6-methylpyridine moiety will be further investigated for developing agents with anti-biofilm and antioxidant activities.

Complexes of 2-Amino-3-methylpyridine and 2-Amino-4-methylbenzothiazole with Ag(I) and Cu(II): Structure and Biological Applications

Coordination complexes (1–4) of 2-amino-4-methylbenzothiazole and 2-amino-3-methylpyridine with Cu(CH3COO)2 and AgNO3 were prepared and characterized by UV/Vis and FT-IR spectroscopy. The molecular structure for single crystals of silver complexes (2 and 4) were determined by X-ray diffraction. The coordination complex (2) is monoclinic with space group P21/c, wherein two ligands are coordinated to a metal ion, affording distorted trigonal geometry around the central Ag metal ion. The efficient nucleophilic center, i.e., the endocyclic nitrogen of the organic ligand, binds to the silver metal. Ligands are coordinated to adopt cis arrangement, predominantly due to steric reasons. The O(2) and O(3) atoms of the NO3− group further play an important role in such type of ligand arrangement by hydrogen bonding with the NH2 group of ligands. Complex (4) is orthorhombic, P212121, comprising two molecules of 2-amino-3-methylpyridine as ligand coordinated with the metal ion, affording a polymeric structure. The coordination behavior of the ligand is identical to that in complex 2, wherein ring nitrogen is coordinated to the metal center and bridged to another metal ion through an NH2 group. The resulting product is polymeric in nature with the Ag metal in the backbone and ligand as the bridge. Compounds (2–4) were found to be luminescent, while 1 did not show such activity. All compounds were screened for their preliminary biological activities such as antibacterial, antioxidant and enzyme inhibition. Compounds exhibited moderate activity in these tests.

Synthesis, DFT, molecular dynamics, and Monte Carlo simulation of a novel thiourea derivative with extraordinary inhibitive properties for mild steel in 0.5 M sulphuric acid

A novel thiourea derivative has been successfully synthesized via green routes and fully characterized by FT-IR, ¹H, ¹³C-NMR, and elemental analysis. The synthetic inhibitor 2-amino-N-(phenylcarbamothioyl) benzamide (APCB) was assessed as a corrosion inhibitor for mild steel (MS) in 0.5 M H₂SO₄. Various electrochemical techniques, such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), have been used to evaluate inhibition efficiency. As a result, EIS and PDP agreed with each other, indicating that APCB exhibits an inhibition performance that exceeds 96% at a concentration of 2 × 10^-4 M and increases with an increase in temperature up to 98% at 333 K. However, PDP measurements showed that APCB is a mixed type of inhibitor. In addition, SEM, EDX, AFM, and contact angle measurements were used as a topological surface characterization technique that confirmed the formation of a protective layer over the MS surface. Additionally, the complex formation was thoroughly confirmed by UV-Vis measurements. The adsorption of APCB proved the highest compliance with the Langmuir adsorption isotherm. Furthermore, density functional theory (DFT) calculations were conducted to establish the correlation between the electronic structure and excellent inhibition efficiency. Moreover, molecular dynamics (MD) simulations were used to find interaction energy in different media. Finally, the adsorption affinity of the MS surface for different concentrations of APCB was verified via Monte Carlo (MC) simulations. Owing to the outcomes of this study, it is remarkable that APCB, with its low cost and simple synthesis, might be an exceptionally prominent option for mild steel protection.

Preparation and Biological Evaluation of Novel Osthole-Derived N-Benzoylthioureas as Insecticide Candidates

To discover novel natural-product-based insecticide candidates, herein, a variety of osthole-derived N-benzoylthioureas were synthesized and assessed for their insecticidal activities against three insect pests. An insecticidal assay showed that most of the target osthole-derived N-benzoylthioureas displayed a more potent and broad-spectrum insecticidal effect than the parent osthole after the introduction of N-benzoylthioureas on the C-3' position of osthole. Compound B24 displayed the most potent growth inhibitory (GI) effect on Mythimna separata Walker, with a final corrected mortality rate of 82.1% when treated with a concentration of 1 mg/mL, which was 1.64- and 1.53-fold higher in comparison to osthole and the botanical insecticide toosendanin, respectively. Compounds B22, B23, and B25 displayed a more promising aphicidal effect on Myzus persicae Sulzer, and their LD₅₀ values were 0.015, 0.017, and 0.019 μg/larvae, respectively, superior to the commercially available insecticide rotenone (0.024 μg/larvae). Derivatives B19, B20, B23, and B25 displayed more potent larvicidal activity against Plutella xylostella Linnaeus, with LC₅₀ values of 0.22, 0.26, 0.15, and 0.30 mg/mL, respectively, exceeding that of rotenone (0.37 mg/mL). Furthermore, both compounds B19 and B23 against P. xylostella were found to be more effective than rotenone in a control efficacy assay under greenhouse conditions. The structure-activity relationship (SAR) suggested that osthole-derived N-benzoylthioureas are more active in most cases when the R group is an electron-withdrawing group than when it is an electron-donating group, especially for halogenated groups. Additionally, the potent compounds B19 and B23 possessed good selectivity and were less toxic to non-target organisms. This study suggests that these osthole-derived N-benzoylthioureas could be further studied in depth as eco-friendly natural product pesticides in crop protection.

Synthesis of novel hybrid pharmacophore of N-((4-sulfamoylphenyl)carbamothioyl)alkanamides as potent carbonic anhydrase-II and 15-lipoxygenase inhibitors

A series of N-((4-sulfamoylphenyl)carbamothioyl)alkanamides (5a-j) were synthesized by the reaction of sulphanilamide in dry acetone with freshly prepared alkyl and acyl isothiocyanates (5a-j). The structures of products were confirmed by IR, ¹ H, and ¹³ C NMR. The synthesized compounds were screened as inhibitors of the bovine erythrocyte carbonic anhydrase isoform II (bCA II) and 15-lipoxygenase enzyme (15-LOX). Most of the derivatives showed significant activity against bCA-II while only few compounds were found active against 15-LOX. Molecular docking studies of most active compounds were carried out against bCA II as well as 15-LOX to rationalize the binding mode and interactions of compound in the active sites. Additionally, the pharmacokinetic properties of the compounds were predicted through computational tools, which reflect that these compounds possess acceptable pharmacokinetic profile and good drug-likeness.

Antimicrobial Activities of Chitosan Derivatives

Considering the challenge created by the development of bacterial and fungal strains resistant to multiple therapeutic variants, new molecules and materials with specific properties against these microorganisms can be synthesized, like those synthesized from biopolymers such as chitosan with improved antimicrobial activities. Antimicrobial activities of seven obtained materials were tested on four reference strains belonging to American Type Culture Collection. The best antimicrobial activity was obtained by functionalization by impregnation of chitosan with quaternary ammonium salts, followed by that obtained by functionalization of chitosan with phosphonium. The lowest antibacterial and antifungal effects were expressed by Ch-THIO and Ch-MBT, but new materials obtained with these extractants may be precursors with a significant role in the direct control of active molecules, such as cell growth factors or cell signaling molecules.

Investigation of the reactivity properties of a thiourea derivative with anticancer activity by DFT and MD simulations

Spectroscopic analysis of 1-(2-fluorophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea (FPTT) is reported. Experimental and theoretical analyses of FPTT, with molecular dynamics (MD) simulations, are reported for finding different parameters like identification of suitable excipients, interactions with water, and sensitivity towards autoxidation. Molecular dynamics and docking show that FPTT can act as a potential inhibitor for new drug. Additionally, local reactivity, interactivity with water, and compatibility of FPTT molecule with frequently used excipients have been studied by combined application of density functional theory (DFT) and MD simulations. Analysis of local reactivity has been performed based on selected fundamental quantum-molecular descriptors, while interactivity with water was studied by calculations of radial distribution functions (RDFs). Compatibility with excipients has been assessed through calculations of solubility parameters, applying MD simulations. Graphical abstract Reactive sites identified.

Monosubstituted Acetophenone Thiosemicarbazones as Potent Inhibitors of Tyrosinase: Synthesis, Inhibitory Studies, and Molecular Docking

A set of 12 monosubstituted acetophenone thiosemicarbazone derivatives (TSCs) were synthesized and their inhibitory properties toward tyrosinase activity were tested. Moreover, their ability to inhibit melanogenesis in the B16F10 murine melanoma cell line was studied. In order to investigate the nature of interactions between the enzyme and the inhibitors, molecular docking to the active site was performed. TSCs 5, 6, 8, and 9 revealed a half maximal inhibitory concentration (IC₅₀) below 1 µM. Compound 6 turned out to be the most potent tyrosinase inhibitor. All investigated compounds showed reversible inhibition of competitive or mixed type. The para-substituted TSCs had higher affinity for the enzyme as compared to their ortho- and meta-analogues. All investigated compounds inhibited melanin production in B16F10 cells at the micromolar level. Molecular docking showed that the sulfur atom of the thiourea moiety penetrates the active site and interacts with copper ions. The above outcomes might be helpful in the design of new tyrosinase inhibitors in the food and cosmetic industries.

Synthesis, characterization and biochemical behaviour of macrocyclic complexes of Zn(II) and Co(II) metals

A series of Zn(II) and Co(II) complexes have been synthesized by template condensation of bis(benzil)-4-chloro-1,2-phenylenediamine and bis(benzil)-4-fluoro-1,2-phenylenediamine, respectively, with 4-chloro-1,2-phenylenediamine and 4-fluoro-1,2-phenylenediamine in the presence of transition metal chlorides. The complexes have been characterized by physicochemical and spectroscopic techniques. Based on these studies, an octahedral geometry has been proposed around the metal ions. The newly synthesized ligands and their metal complexes have been screened for antimicrobial and anticancer activities. The in vitro cytotoxicity towards the HeLa cell line has been evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

The Use of Copper as an Antimicrobial Agent in Health Care, Including Obstetrics and Gynecology

Health care-associated infections (HAIs) are a global problem associated with significant morbidity and mortality. Controlling the spread of antimicrobial-resistant bacteria is a major public health challenge, and antimicrobial resistance has become one of the most important global problems in current times. The antimicrobial effect of copper has been known for centuries, and ongoing research is being conducted on the use of copper-coated hard and soft surfaces for reduction of microbial contamination and, subsequently, reduction of HAIs. This review provides an overview of the historical and current evidence of the antimicrobial and wound-healing properties of copper and explores its possible utility in obstetrics and gynecology.

Chloridobis(ethane-1,2-diamine)(4-fluoroaniline)cobalt(III) dichloride monohydrate

The hydrated title salt, [CoCl(C6H6FN)(C2H8N2)2]Cl2·H2O, comprises of one chloridobis(ethane-1,2-diamine)(4-fluoroaniline)cobalt(III) cation, two chloride counter-anions and a water molecule of crystallization. The CoIII ion has a distorted octahedral environment and is surrounded by four N atoms in the equatorial plane, with a fifth N atom and one Cl− ligand occupying the axial positions. One of the methylene C groups in one of the ethane-1,2-diamine ligands is disordered over two set of sites in a 0.832 (10):0.168 (10) ratio. In the crystal, the complex cation, the two counter-anions and the water molecule of crystallization are linked via N—H...Cl, O—H...Cl and C—H...Cl hydrogen bonds, generating rings with R 4 2(8), R 2 1(6), R 4 2(10) and R 2 2(6) graph-set motifs within a three-dimensional network.

Thiosemicarbazones with tyrosinase inhibitory activity

Tyrosinase plays an essential role in melanogenesis. Excess production of melanin can be a reason for hyperpigmentation skin disorders in mammals and enzymatic browning in plant-derived foods. Catalyzing the rate-limiting step of melanin synthesis, tyrosinase has become the most studied target for melanogenesis inhibition. Over the past ten years, a number of synthetic thiosemicarbazone derivatives have been reported to possess strong tyrosinase inhibitory properties with IC₅₀ values below 1 μM, placing them among the most potent tyrosinase inhibitors. This review gives an overview of tyrosinase activity and describes tyrosinase-inhibiting thiosemicarbazones in terms of their structure-activity relationships, kinetics of enzyme inhibition and mechanism of action. Results of the studies of thiosemicarbazones as tyrosinase inhibitors from over 20 research articles have been analyzed, compared and summarized in the present paper. Using thiosemicarbazones as tyrosinase inhibitors is a promising approach in developing anti-melanogenetic agents for skin-whitening cosmetics and anti-browning agents for food.

Synthesis of diphenylamine macrocycles and their anti-inflammatory effects

A collection of fourteen diphenylamine macrocyclic derivatives containing a peptide chain with different substituents was synthesized using a protocol of two Ugi four component reactions (Ugi-4CR) and a Buchwald–Hartwig macrocyclization.

Evaluation of Novel N-(Dibenzylcarbamothioyl)benzamide Derivatives as Antibacterial Agents by Using DFT and Drug-Likeness Assessment

Isomers of monothioureas, 2a–2d, derived from the reaction of disubstituted benzoyl isothiocyanate and dibenzylamine were synthesised and characterised by using elementary analysis CHNS and IR, 1H NMR, and 13C NMR spectroscopies. The compounds were screened for their in vitro antibacterial activity by using selected Gram-positive bacteria, and moderate inhibition activity was displayed for compound 2b with the value of inhibition zone 11 ± 0.8 mm at a concentration of 50 mg/ml. The outcomes of Lipinski’s rule of five assessment appeared to be in agreement with all compounds as they adhered to most of the rules, in which they can be preliminarily classified as active drug-like. The frontier molecular orbitals (HOMO and LUMO) for halogen-substituted 3,4-dichloro (2a) and 3,4-difluoro (2b) were also determined by applying the computational method of density functional theory (DFT) to determine their relationship as a molecular descriptor in antibacterial activities. The value of LUMO energy for compound 2b (1.8229 eV) is lower than that of compound 2a (1.8492 eV) which indicates higher antibacterial activities.

Chloridobis(ethane-1,2-diamine-κ2 N,N′)(3-methylpyridine-κN)cobalt(III) dichloride monohydrate

In the title hydrated salt, [CoCl(C6H7N)(C2H8N2)2]Cl2·H2O, the CoIII ion exhibits a distorted octahedral coordination envirnoment defined by four N atoms of two ethane-1,2-diamine ligands, another N atom of the pyridine ligand and a Cl− ligand. The pyridine N atom and the Cl− ligand are in cis positions relative to each other. The crystal packing is dominated by intermolecular N—H...Cl, O—H...Cl and O—H...H hydrogen-bonding interactions involving the amino groups of the complex cation, the lattice water molecule and the non-coordinating Cl− anions. Weak C—H...Cl interactions consolidate the three-dimensional hydrogen-bonded network structure.

cis-Bromido(n-butylamine-κN)bis(ethene-1,2-diamine-κ2 N,N′)cobalt(III) dibromide

In the title compound, [CoBr(C2H8N2)2(C4H11N)]Br2, the cobalt(III) ion has a distorted octahedral coordination environment and is surrounded by four N atoms in the equatorial plane made up of three N atoms from the two ethylenediamine ligands and the remaining N from the n-butyl substituent, with the other N atom from the ethylenediamine ligand and the Br atom occupying the axial positions. In the crystal, the complex cation and the two counter-anions are linked via N—H...Br and C—H...Br hydrogen bonds, forming a three-dimensional network. The crystal studied was refined as a two-component inversion twin.

cis-Bromidobis(ethylene-1,2-diamine)(methylamine)cobalt(III) dibromide

In the title compound, [CoBr(CH5N)(C2H8N2)2]Br2, the cobalt(III) ion has a distorted octahedral coordination environment and is ligated by four N atoms in the equatorial plane, with an additional N atom and a Br− ion occupying the axial positions. In the crystal, the complex cation and the two counter-anions are linked via N—H...Br and C—H...Br hydrogen bonds, forming a supramolecular framework.

Synthesis, structural and antimicrobial studies of type II topoisomerase-targeted copper(II) complexes of 1,3-disubstituted thiourea ligands

A series of Cu(II) complexes of 3-(trifluoromethyl)phenylthiourea derivatives was synthesized. Their structural properties were investigated by spectroscopic techniques (infrared and electron paramagnetic resonance), as well as molecular modeling. All studied coordination compounds are mononuclear complexes containing two chelating ligands bonded to the metal cation via S and deprotonated N atoms. The new chelates were evaluated for their antimicrobial potency. The complex of 1-(3,4-dichlorophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea (3) presented the highest activity against Gram-positive pathogens, even stronger than the activity of its non-complexed counterpart and the reference drug. The compound also prevented the biofilm formation of methicillin-resistant and standard strains of staphylococcal cocci. The title derivatives were found to be effective inhibitors of DNA gyrase and topoisomerase IV isolated from Staphylococcus aureus. The binding modes of the ligand L3 with DNA gyrase and topoisomerase IV were presented.