Synthesis and Antimicrobial Activity of 4-Chloro-3-Nitrophenylthiourea Derivatives Targeting Bacterial Type II Topoisomerases

Proapoptotic effects of halogenated bis-phenylthiourea derivatives in cancer cells

New halogenated thiourea derivatives were synthesized via the reaction of substituted phenylisothiocyanates with aromatic amines. Their cytotoxic activity was examined in in vitro studies against solid tumors (SW480, SW620, PC3), a hematological malignance (K-562), and normal keratinocytes (HaCaT). Most of the compounds were more effective against SW480 (1a, 3a, 3b, 5j), K-562 (2b, 3a, 4a), or PC3 (5d) cells than cisplatin, with favorable selectivity. Their anticancer mechanisms were studied by Annexin V-fluorescein-5-isothiocyanate apoptosis, caspase-3/caspase-7 assessment, cell cycle analysis, interleukin-6 (IL-6) release inhibition, and reactive oxygen species (ROS) generation assay. Thioureas 1a, 2b, 3a, and 4a were the most potent activators of early apoptosis in K-562 cells, and substances 1a, 3b, 5j triggered late-apoptosis or necrosis in SW480 cells. This proapoptotic effect was proved by the significant increase of caspase-3/caspase-7 activation. Cell cycle analysis revealed that derivatives 1a, 3a, 5j increased the number of SW480 and K-562 cells in the sub-G1 and/or G0/G1 phases, and one evoked cycle arrest at the G2 phase. The most potent thioureas inhibited IL-6 cytokine secretion from PC3 cells and both colon cancer cell lines. Apoptosis-inducing compounds also increased ROS production in all tumor cell cultures, which may enhance their anticancer properties.

Synthesis, Structural Characterization and Biological Activity Evaluation of Novel Cu(II) Complexes with 3-(trifluoromethyl)phenylthiourea Derivatives

Copper complexes with 1,3-disubstituted thiourea derivatives, all containing 3-(trifluoromethyl)phenyl tail and 1-alkyl/halogen-phenyl substituent, were synthesized. The experimental spectroscopic studies and theoretical calculation revealed that two ligands coordinate to Cu(II) in a bidentate fashion via thiocarbonyl S and deprotonated N atoms of thiourea moiety. Such monomers are characteristic of alkylphenylthiourea complexes, whereas the formation of a sandwich-type dimer is observed for halogeno derivatives. For the first time, the structural identifications of CuN₂S₂-based complexes using experimental and theoretical X-ray absorption near edge structure are demonstrated. The dimeric halogeno derivatives showed higher antimicrobial activity in comparison with alkylphenylthiourea complexes. The Cu(II) complex of 1-(4-chloro-3-nitrophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea was active against 19 strains of methicillin-resistant Staphylococci (MIC = 2 µg/mL). This derivative acted as a dual inhibitor of DNA gyrase and topoisomerase IV isolated from Staphylococcus aureus. Additionally, complexes of halogenphenylthiourea strongly inhibited the growth of mycobacteria isolated from tuberculosis patients, even fourfold stronger than the reference isoniazid. The complexes exerted weak to moderate antitumor activity (towards SW480, SW620, and PC3) being non-toxic towards normal HaCaT cells.

Investigation of the Mechanisms of Cytotoxic Activity of 1,3-Disubstituted Thiourea Derivatives

Substituted thiourea derivatives possess confirmed cytotoxic activity towards cancer but also normal cells. To develop new selective antitumor agents, a series of 3-(trifluoromethyl)phenylthiourea analogs were synthesized, and their cytotoxicity was evaluated in vitro against the cell line panel. Compounds 1-5, 8, and 9 were highly cytotoxic against human colon (SW480, SW620) and prostate (PC3) cancer cells, and leukemia K-562 cell lines (IC₅₀ ≤ 10 µM), with favorable selectivity over normal HaCaT cells. The derivatives exerted better growth inhibitory profiles towards selected tumor cells than the reference cisplatin. Compounds incorporating 3,4-dichloro- (2) and 4-CF₃-phenyl (8) substituents displayed the highest activity (IC₅₀ from 1.5 to 8.9 µM). The mechanisms of cytotoxic action of the most effective thioureas 1-3, 8, and 9 were studied, including the trypan blue exclusion test of cell viability, interleukin-6, and apoptosis assessments. Compounds reduced all cancerous cell numbers (especially SW480 and SW620) by 20-93%. Derivatives 2 and 8 diminished the viability of SW620 cells by 45-58%. Thioureas 1, 2, and 8 exerted strong pro-apoptotic activity. Compound 2 induced late apoptosis in both colon cancer cell lines (95-99%) and in K-562 cells (73%). All derivatives acted as inhibitors of IL-6 levels in both SW480 and SW620 cells, decreasing its secretion by 23-63%.

The Cytotoxic Effect of Copper (II) Complexes with Halogenated 1,3-Disubstituted Arylthioureas on Cancer and Bacterial Cells

A series of eight copper (II) complexes with 3-(4-chloro-3-nitrophenyl)thiourea were designed and synthesized. The cytotoxic activity of all compounds was assessed in three human cancer cell lines (SW480, SW620, PC3) and human normal keratinocytes (HaCaT). The complexes 1, 3, 5, 7 and 8 were cytotoxic to the studied tumor cells in the low micromolar range, without affecting the normal cells. The complexes 1, 3, 7 and 8 induced lactate dehydrogenase (LDH) release in all cancer cell lines, but not in the HaCaT cells. They provoked early apoptosis in pathological cells, especially in SW480 and PC3 cells. The ability of compounds 1, 3, 7 and 8 to diminish interleukin-6 (IL-6) concentration in a cell was established. For the first time, the influence of the most promising Cu (II) complexes on intensities of detoxifying and reactive oxygen species (ROS) scavenging the enzymes of tumor cells was studied. The cytotoxic effect of all copper (II) conjugates against standard and hospital bacterial strains was also proved.

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.

G protein-coupled receptor binding and pharmacological evaluation of indole-derived thiourea compounds

Four 2-(1H-indol-3-yl)ethylthiourea derivatives were prepared by condensation of 2-(1H-indol-3-yl)ethanamine with the corresponding aryl/alkylisothiocyanates in a medium-polarity solvent. Their structures were confirmed by spectral techniques, and the molecular structure of 3 was determined by X-ray crystal analysis. For all derivatives, the binding affinities at the 5-HT_2A and 5-HT_2C receptors, as well as their functional activities at the 5-HT_1A and D₂ receptors, were determined. The arylthioureas 1 and 4 were the most active at the 5-HT_1A receptor, showing, at the same time, significant selectivity over the studied 5-HT₂ and D₂ receptor subtypes. The compounds were tested for their pharmacological activities within the central nervous system in relevant mouse models. The involvement of the serotonergic system in the activity of 1 and 4 was indicated. The antinociceptive action of 4 was linked to its anti-inflammatory activity.

Magnetic-field-tuned phase transition of a molecular material from the isolated-spin to the coupled-spin regime

A quantum phase transition, as a consequence of spin-entanglements caused by Cu–Cu exchange couplings, explains EPR measurements in a new monomeric Cu^II compound.

Synthetic small molecules as anti-biofilm agents in the struggle against antibiotic resistance

Biofilm formation significantly contributes to microbial survival in hostile environments and it is currently considered a key virulence factor for pathogens responsible for serious chronic infections. In the last decade many efforts have been made to identify new agents able to modulate bacterial biofilm life cycle, and many compounds have shown interesting activities in inhibiting biofilm formation or in dispersing pre-formed biofilms. However, only a few of these compounds were tested using in vivo models for their clinical significance. Contrary to conventional antibiotics, most of the anti-biofilm compounds act as anti-virulence agents as they do not affect bacterial growth. In this review we selected the most relevant literature of the last decade, focusing on the development of synthetic small molecules able to prevent bacterial biofilm formation or to eradicate pre-existing biofilms of clinically relevant Gram-positive and Gram-negative pathogens. In addition, we provide a comprehensive list of the possible targets to counteract biofilm formation and development, as well as a detailed discussion the advantages and disadvantages of the different current biofilm-targeting strategies.

Disubstituted 4-Chloro-3-nitrophenylthiourea Derivatives: Antimicrobial and Cytotoxic Studies

4-Chloro-3-nitrophenylthioureas 1–30 were synthesized and tested for their antimicrobial and cytotoxic activities. Compounds exhibited high to moderate antistaphylococcal activity against both standard and clinical strains (MIC values 2–64 μg/mL). Among them derivatives with electron-donating alkyl substituents at the phenyl ring were the most promising. Moreover, compounds 1–6 and 8–19 were cytotoxic against MT-4 cells and various other cell lines derived from human hematological tumors (CC₅₀ ≤ 10 μM). The influence of derivatives 11, 13 and 25 on viability, mortality and the growth rate of immortalized human keratinocytes (HaCaT) was observed.

Synthesis, Structural Studies and Biological Evaluation of Connections of Thiosemicarbazide, 1,2,4-Triazole and 1,3,4-Thiadiazole with Palmitic Acid

Thirty new derivatives of palmitic acid were efficiently synthesized. All obtained compounds can be divided into three groups of derivatives: Thiosemicarbazides (compounds 1-10), 1,2,4-triazoles (compounds 1a-10a) and 1,3,4-thiadiazoles (compounds 1b-10b) moieties. ¹H-NMR, 13C-NMR and MS methods were used to confirm the structure of derivatives. All obtained compounds were tested in vitro against a number of microorganisms, including Gram-positive cocci, Gram-negative rods and Candida albicans. Compounds 4, 5, 6, 8 showed significant inhibition against C. albicans. The range of MIC values was 50-1.56 μg/mL. The halogen atom, especially at the 3rd position of the phenyl group was significantly important for antifungal activity. The biological activity against Candida albicans and selected molecular descriptors were used as a basis for QSAR models, that have been determined by means of multiple linear regression. The models have been validated by means of the Leave-One-Out Cross Validation. The obtained QSAR models were characterized by high determination coefficients and good prediction power.

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.

New thiourea and 1,3-thiazolidin-4-one derivatives effective on the HIV-1 virus

Thiourea derivatives have been reported to possess many biological activities, among them antiviral and antitumoral properties. As part of our continuing effort to develop new active compounds, we report the synthesis and the evaluation of new fifteen thiourea derivatives with 1,3-benzothiazole-2-yl moiety, among them a group of biologically active (1-7) also underwent cyclization to 1,3-thiazolidin-4-ones. Molecular structure of four compounds (4, 13, 15 and 3a) was determined by an X-ray crystallography. We here report the evaluation of their cytotoxicity against human leukaemia/lymphoma- and solid tumour-derived cell lines and of their antiviral activity against HIV-1 and representatives of ssRNA and dsDNA viruses. Derivative 5 showed an interesting activity against HIV-1 wild type and against variants carrying clinically relevant mutations. A colorimetric enzyme immunoassay clarified its mode of action as a non-nucleoside inhibitor of the reverse transcriptase.

Spectroscopic, single crystal XRD structure, DFT and molecular dynamics investigation of 1-(3-chloro-4-fluorophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea

The title compound 1-(3-chloro-4-fluorophenyl)-3-[3-(trifluoromethyl) phenyl]thiourea (ANF-2) was synthesized and structurally characterized by single crystal XRD.