Sulfonyl thioureas with a benzo[d]thiazole ring as dual acetylcholinesterase/butyrylcholinesterase and human monoamine oxidase A and B inhibitors: An in vitro and in silico study.

A series of sulfonyl thioureas 6a-q containing a benzo[d]thiazole ring with an ester functional group was synthesized from corresponding substituted 2-aminobenzo[d]thiazoles 3a-q and p-toluenesulfonyl isothiocyanate. They had remarkable inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase (MAO)-A, and MAO-B. Among thioureas, several compounds had notable activity in the order of 6k > 6 h > 6c (AChE), 6j > 6g > 6k (BChE), 6k > 6g > 6f (MAO-A), and 6i > 6k > 6h (MAO-B). Compound 6k was an inhibitor of interest due to its potent or good activity against all studied enzymes, with IC50 values of 0.027 ± 0.008 µM (AChE), 0.043 ± 0.004 µM (BChE), 0.353 ± 0.01 µM (MAO-A), and 0.716 ± 0.02 µM (MAO-B). This inhibitory capacity was comparable to that of the reference drugs for each enzyme. Kinetic studies of two compounds with potential activity, 6k (against AChE) and 6j (against BChE), had shown that both 6k and 6j followed competitive-type enzyme inhibition, with Ki constants of 24.49 and 12.16 nM, respectively. Induced fit docking studies for enzymes 4EY7, 7BO4, 2BXR, and 2BYB showed active interactions between sulfonyl thioureas of benzo[d]thiazoles and the residues in the active pocket with ligands 6k, 6i, and 6j, respectively. The stability of the ligand-protein complexes while each ligand entered the active site of each enzyme (4EY7, 7BO4, 2BXR, or 2BYB) was confirmed by molecular dynamics simulations.

Antimycobacterial and anti-inflammatory activities of thiourea derivatives focusing on treatment approaches for severe pulmonary tuberculosis.

Tuberculosis (TB) remains a serious public health problem and one of the main concern is the emergence of multidrug-resistant and extensively resistant TB. Hyper-reactive patients develop inflammatory necrotic lung lesions that aggravate the pathology and facilitate transmission of mycobacteria. Treatment of severe TB is a major clinical challenge that has few effective solutions and patients face a poor prognosis, years of treatment and different adverse drug reactions. In this work, fifteen novel and thirty-one unusual thiourea derivatives were synthesized and evaluated in vitro for their antimycobacterial and anti-inflammatory potential and, in silico for ADMET parameters and for structure-activity relationship (SAR). Thioureas derivatives 10, 15, 16, 28 and 29 that had shown low cytotoxicity and high activities were selected for further investigation, after SAR study. These five thioureas derivatives inhibited Mtb H37Rv growth in bacterial culture and in infected macrophages, highlighting thiourea derivative 28 (MIC50 2.0 ± 1.1 and 2.3 ± 1.1 µM, respectively). Moreover, these compounds were active against the hypervirulent clinical Mtb strain M299, in bacterial culture, especially 16, 28 and 29, and in extracellular clumps, highlighting 29, with MIC50 5.6 ± 1.2 µM. Regarding inflammation, they inhibited NO through the suppression of iNOS expression, and also inhibited the production of TNF-α and IL-1ß. In silico studies were carried out suggesting that these five compounds could be administered by oral route and have low toxicological effects when compared to rifampicin. In conclusion, our data show that, at least, thiourea derivatives 16, 28 and 29 are promising antimycobacterial and anti-inflammatory agents, and candidates for further prospective studies aiming new anti-TB drugs, that can be used on a dual approach for the treatment of severe TB cases associated with exacerbated inflammation.

Synthesis of New Thiourea-Metal Complexes with Promising Anticancer Properties.

In this work, two thiourea ligands bearing a phosphine group in one arm and in the other a phenyl group (T2) or 3,5-di-CF3 substituted phenyl ring (T1) have been prepared and their coordination to Au and Ag has been studied. A different behavior is observed for gold complexes, a linear geometry with coordination only to the phosphorus atom or an equilibrium between the linear and three-coordinated species is present, whereas for silver complexes the coordination of the ligand as P^S chelate is found. The thiourea ligands and their complexes were explored against different cancer cell lines (HeLa, A549, and Jurkat). The thiourea ligands do not exhibit relevant cytotoxicity in the tested cell lines and the coordination of a metal triggers excellent cytotoxic values in all cases. In general, data showed that gold complexes are more cytotoxic than the silver compounds with T1, in particular the complexes [AuT1(PPh3)]OTf, the bis(thiourea) [Au(T1)2]OTf and the gold-thiolate species [Au(SR)T1]. In contrast, with T2 better results are obtained with silver species [AgT1(PPh3)]OTf and the [Ag(T1)2]OTf. The role played by the ancillary ligand bound to the metal is important since it strongly affects the cytotoxic activity, being the bis(thiourea) complex the most active species. This study demonstrates that metal complexes derived from thiourea can be biologically active and these compounds are promising leads for further development as potential anticancer agents.

An efficient and concise synthesis of a selective small molecule non-peptide inhibitor of cathepsin L: KGP94.

KGP94 is a potent, selective, and competitive inhibitor of the lysosomal endopeptidase enzyme (Cathepsin L) currently in preclinical trials for the treatment of metastatic cancer, which is a leading cause of cancer-associated death. Herein, we report two new synthetic routes for synthesizing the target compound through four consecutive steps, using a Weinreb amide approach starting from a common 3-bromobenzoyl chloride. A key step in the approach is a coupling reaction of a readily available Grignard reagent with amide 4 to produce 6, a previously unreported coupling pattern. These new strategies offer an efficient and alternative approach to synthesis of target compound with an excellent overall yield.

Discovery of new human Sirtuin 5 inhibitors by mimicking glutaryl-lysine substrates.

Human sirtuin 5 (SIRT5) plays pivotal roles in metabolic pathways and other biological processes, and is involved in several human diseases including cancer. Development of new potent and selective SIRT5 inhibitors is currently desirable to provide potential therapeutics for related diseases. Herein, we report a series of new 3-thioureidopropanoic acid derivatives, which were designed to mimic the binding features of SIRT5 glutaryl-lysine substrates. Structure-activity relationship studies revealed several compounds with low micromolar inhibitory activities to SIRT5. Computational and biochemical studies indicated that these compounds exhibited competitive SIRT5 inhibition with respect to the glutaryl-lysine substrate rather than nicotinamide adenine dinucleotide cofactor. Moreover, they showed high selectivity for SIRT5 over SIRT1-3 and 6 and could stabilize SIRT5 proteins as revealed by thermal shift analyses. This work provides an effective substrate-mimicking strategy for future inhibitor design, and offers new inhibitors to investigate their therapeutic potentials in SIRT5-associated disease models.

Multitarget-directed therapeutics: (Urea/thiourea)2 derivatives of diverse heterocyclic-Lys conjugates.

The synthesis of a new small library of molecules containing bis-urea/thiourea pendants in lysine conjugated to three different heterocycles is described. The heterocycles used in this study have benzisoxazole/piperazine/piperidine units. After a detailed antimicrobial, antioxidant, and anti-inflammatory evaluation, it was found that the most active compounds are 10, 11, 14, 15, 18, 19 and 10, 11, 19 and 8, 9, 12, 13, 16, 17, respectively. Further, it was observed that the presence of all three entities, that is, urea/thiourea, the substituent (OMe/F), as well as the heterocycle, is highly essential for exerting potent activity. Among the heterocycles, the presence of isoxazole seems to be highly beneficial for exerting good potency. In continuation, docking studies have revealed extraordinary binding efficiency for some of the active compounds. Given their potent biological results and docking score, some of the title compounds could be potential drug candidates for microbial-related diseases and provide a basis for future research into the development of molecules possessing multitask ability.

Synthesis, X-ray, Hirshfeld surface analysis, exploration of DNA binding, urease enzyme inhibition and anticancer activities of novel adamantane-naphthyl thiourea conjugate.

1-(adamantane-1-carbonyl-3-(1-naphthyl)) thiourea (C22H24N2OS (4), was synthesized by the reaction of freshly prepared adamantane-1-carbonyl chloride from corresponding acid (3) with ammonium thiocyanate in 1:1 M ratio in dry acetone to afford the adamantane-1-carbonyl isothiocyanate (2) in situ followed by treatment with 1-naphthyl amine (3). The structure was established by elemental analyses, FTIR, 1H, 13C NMR and mass spectroscopy. The molecular and crystal structure were determined by single crystal X-ray analysis. It belongs to triclinic system P - 1 space group with a = 6.7832(5) Å, b = 11.1810(8) Å, c = 13.6660(10) Å, α = 105.941(6)°, ß = 103.730(6)°, γ = 104.562(6)°, Z = 2, V = 910.82(11) Å3. The naphthyl group is almost planar. In the crystal structure, intermolecular CH···O hydrogen bonds link the molecules into centrosymmetric dimers, enclosing R22(14) ring motifs, while the intramolecular NH···O hydrogen bonds enclose S(6) ring motifs, in which they may be effective in the stabilization of the structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H … H (59.3%), H … C/C … H (19.8%) and H … S/S … H (10.1%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. DFT, molecular docking and urease inhibition studies revealed stability and electron withdrawing nature of 4 as compared to DNA base pairs and residues of urease. The DNA binding results from docking, UV- visible spectroscopy, and viscosity studies indicated significant binding of 4 with the DNA via intercalation and groove binding. Further investigation of the compound was done on hepatocellular carcinoma; Huh-7 cell line as well as normal human embryonic kidney; Hek-293 cell line. The compound showed significant cytotoxic activity against Huh-7 cells in comparison to normal Hek-293 cells indicating selective cytotoxicity towards cancer cells.

Continuous-Flow Synthesis of Thioureas, Enabled by Aqueous Polysulfide Solution.

We have developed the continuous-flow synthesis of thioureas in a multicomponent reaction starting from isocyanides, amidines, or amines and sulfur. The aqueous polysulfide solution enabled the application of sulfur under homogeneous and mild conditions. The crystallized products were isolated by simple filtration after the removal of the co-solvent, and the sulfur retained in the mother liquid. Presenting a wide range of thioureas synthesized by this procedure confirms the utility of the convenient continuous-flow application of sulfur.

Molecular structure, NBO analysis of the hydrogen-bonded interactions, spectroscopic (FT-IR, FT-Raman), drug likeness and molecular docking of the novel anti COVID-2 molecule (2E)-N-methyl-2-[(4-oxo-4H-chromen-3-yl)methylidene]-hydrazinecarbothioamide (Dimer) - quantum chemical approach.

Prospective antiviral molecule (2E)-N-methyl-2-[(4-oxo-4H-chromen-3-yl)methylidene]-hydrazinecarbothioamide has been probed using Fourier transform infrared (FTIR), FT-Raman and quantum chemical computations. The geometry equilibrium and natural bond orbital analysis have been carried out with density functional theory employing Becke, 3-parameter, Lee-Yang-Parr method with the 6-311G++(d,p) basis set. The vibrational assignments pertaining to different modes of vibrations have been augmented by normal coordinate analysis, force constant and potential energy distributions. Drug likeness and oral activity have been carried out based on Lipinski's rule of five. The inhibiting potency of 2(2E)-methyl-2-[(4-oxo-4H-chromen-3-yl)methylidene]-hydrazinecarbothioamide has been investigated by docking simulation against SARS-CoV-2 protein. The optimized geometry shows a planar structure between the chromone and the side chain. Differences in the geometries due to the substitution of the electronegative atom and intermolecular contacts due to the chromone and hydrazinecarbothioamide were analyzed. NBO analysis confirms the presence of two strong stable hydrogen bonded NH⋯O intermolecular interactions and two weak hydrogen bonded CH⋯O interactions. The red shift in NH stretching frequency exposed from IR substantiates the formation of NH⋯O intermolecular hydrogen bond and the blue shift in CH stretching frequency substantiates the formation of CH⋯O intermolecular hydrogen bond. Drug likeness, absorption, distribution, metabolism, excretion and toxicity property gives an idea about the pharmacokinetic properties of the title molecule. The binding energy of the nonbonding interaction with Histidine 41 and Cysteine 145, present a clear view that 2(2E)-methyl-2-[(4-oxo-4H-chromen-3-yl)methylidene]-hydrazinecarbothioamide can irreversibly interact with SARS-CoV-2 protease.

Understanding the enzymatic inhibition of intestinal alkaline phosphatase by aminophenazone-derived aryl thioureas with aided computational molecular dynamics simulations: synthesis, characterization, SAR and kinetic profiling.

The work presented in this paper aims toward the synthesis of aryl thiourea derivatives 4a-l of pyrazole based nonsteroidal anti-inflammatory drug named 4-aminophenazone, as potential inhibitors of intestinal alkaline phosphatase enzyme. The screening of synthesized target compounds 4a-l for unraveling the anti-inflammatory potential against calf intestinal alkaline phosphatase gives rise to lead member 4c possessing IC50 value 0.420 ± 0.012 µM, many folds better than reference standard used (KH2PO4 IC50 = 2.8 ± 0.06 µM and L-phenylalanine IC50 = 100 ± 3.1 µM). SAR for unfolding the active site binding pocket interaction along with the mode of enzyme inhibition based on kinetic studies is carried out which showed non-competitive binding mode. The enzyme inhibition studies were further supplemented by molecular dynamic simulations for predicting the protein behavior against active inhibitors 4c and 4g during docking analysis. The preliminary toxicity of the synthesized compounds was determined by using brine shrimp assay. This work also includes detailed biochemical analysis along with RO5 parameters for all the newly synthesized drug derivatives 4a-l.

Synthesis and Erythroid Induction Activity of New Thiourea Derivatives.

BACKGROUND: The use of medicinal agents to augment the fetal hemoglobin (HbF) accretion is an important approach for the treatment of sickle-cell anemia and ß-thalassemia. HbF inducers have the potential to reduce the clinical symptoms and blood transfusion dependence in the patients of ß- hemoglobinopathies. OBJECTIVE: The current study was aimed to examine the erythroid induction potential of newly synthesized thiourea derivatives. METHODS: Thiourea derivatives 1-27 were synthesized by using environmentally friendly methods. Compounds 3, 10 and 22 were found to be new. The structures of synthesized derivatives were deduced by using various spectroscopic techniques. These derivatives were then evaluated for their erythroid induction using the human erythroleukemic K562 cell line, as a model. The benzidine-H2O2 assay was used to evaluate erythroid induction, while HbF expression was studied through immunocytochemistry using the Anti-HbF antibody. Cytotoxicity of compounds 1-27 was also evaluated on mouse fibroblast 3T3 cell line and cancer Hela cell line using MTT assay. RESULT: All the compounds (1-27) have not been reported for their erythroid induction activity previously. Compounds 1, 2, and 3 were found to be the potent erythroid inducing agents with % induction of 45± 6.9, 44± 5.9, and 41± 6.1, at 1.56, 0.78, and 0.78 µM concentrations, respectively, as compared to untreated control (12 ± 1 % induction). Furthermore, compound 1, 2, and 3 significantly induced fetal hemoglobin the expression up to 4.2-fold, 4.06-fold, and 3.52-fold, respectively, as compared to untreated control. Moreover, the compounds 1-4, 6-9, 11, 12, 15, 17, 19, 22, 23, and 25 were found to be non-cytotoxic against the 3T3 cell line. CONCLUSION: This study signifies that the compounds reported here may serve as the starting point for the designing and development of new fetal hemoglobin inducers for the treatment of ß- hemoglobinopathies.

Synthesis of New Thioureas Derivatives and Evaluation of Their Efficacy as Proliferation Inhibitors in MCF-7 Breast Cancer Cells by Using 99mTc-MIBI Radiotracer.

BACKGROUND AND OBJECTIVES: Anti-tumor activity of some thioureas derivatives is well documented in literature and received considerable attention. The present study aims to synthesize and characterize some novel thioureas and carbonylthioureas as anti-tumor agents for MCF-7 breast cancer cells in vitro and in vivo. MATERIALS AND METHODS: Several 1-allyl-3-(substituted phenyl), N,N'-(phenylene) bis(3- allyldithithiourea) and 1-cyclopropanecarbonyl-3-(substituted phenyl)-thioureas derivatives were synthesized and confirmed by FT-IR spectroscopy, NMR and 13C-NMR. Anti-tumor activity of these compounds was determined by various in vitro and in vivo assays including; MTT, tumor volume measurement as well as,99mTc-MIBI tumor uptake in MCF-7 tumor bearing nude mice. RESULTS: Among all of the synthesized compounds, some thioureas derivatives [3i] and [4b] at 100 nM concentration exhibited significant inhibitory effects on the proliferation of MCF-7 cell in vitro. However, this inhibition was not observed in HUVEC human endothelial normal cells. In vivo anti-tumor effects of the synthesized compounds on MCF-7 xenograft mouse models demonstrated a reduction in the tumor volume for various concentrations between 2 to 10 mg/kg after 21 days. These effects were comparable with Tamoxifen as standard anti-estrogen drug. According to the 99mTc-MIBI biodistribution result, treatment of MCF-7 bearing nude mice with both [3i] and [4b] compounds at the maximum concentration (10 mg/kg) can lead to a significant decrease of 99mTc- MIBI tumor uptake. CONCLUSION: Compounds [3i] and [4b] suppressed the growth of MCF-7 cells in the xenograft nude mice at the doses that were well-tolerated. Our study suggests that these new compounds with their significant anti-tumor effects, may serve as useful candidates for breast cancer therapy.

Design, Synthesis, Pharmacological Evaluation, In silico Modeling, Prediction of Toxicity and Metabolism Studies of Novel 1-(substituted)-2-methyl- 3-(4-oxo-2-phenyl quinazolin-3(4H)-yl)isothioureas.

BACKGROUND: Although exhaustive efforts to prevent and treat tuberculosis (TB) have been made, the problem still continues due to multi-drug-resistant (MDR) and extensively drugresistant TB (XDR-TB). It clearly highlights the urgent need to develop novel "druggable" molecules for the co-infection treatment and strains of MDR-TB and XDR-TB. OBJECTIVE: In this approach, a hybrid molecule was created by merging two or more pharmacophores. The active site of targets may be addressed by each of the pharmacophores and proffers the opportunity for selectivity. In addition, it also reduces undesirable side effects and drug-resistance. METHODS: In this study, a novel quinazolinone analog was designed and synthesized by substituting thiourea nucleus and phenyl ring at N-3 and C-2 position of quinazoline ring, respectively. All title compounds were tested for antitubercular activity by in vitro M. tuberculosis and anti-human immunodeficiency virus (HIV) activity by MT-4 cell assay method. The agar dilution method was used to test the antibacterial potency of entire prepared derivatives against various strains of grampositive and gram-negative microorganisms. RESULTS: The title compounds, 1-(substituted)-2-methyl-3-(4-oxo-2-phenyl quinazolin-3(4H)-yl) isothioureas (QTS1 - QTS15) were synthesized by the reaction between key intermediate 3-amino- 2-phenylquinazolin-4(3H)-one with various alkyl/aryl isothiocyanates followed by methylation with dimethyl sulphate. Among the series, compound 1-(3-chlorophenyl)-2-methyl-3-(4-oxo-2-phenyl quinazolin- 3(4H)-yl) isothioureas (QTS14) showed the highest potency against B. subtilis, K. pneumonia and S. aureus at 1.6 µg/mL. The compound QTS14 exhibited the most potent antitubercular activity at the MIC of 0.78 µg/mL and anti-HIV activity at 0.97 µg/mL against HIV1 and HIV2. CONCLUSION: The results obtained from this study confirm that the synthesized and biologically evaluated quinazolines showed promising antimicrobial, antitubercular and anti-HIV activities. The new scaffolds proffer a plausible lead for further development and optimization of novel antitubercular and anti-HIV drugs.

Coumarin-Thiourea Hybrids Show Potent Carbonic Anhydrase IX and XIII Inhibitory Action.

A series of coumarin-thiourea hybrids (4 a-o) has been synthesized, and the compounds have been evaluated against the tumour associated transmembrane isoform, human (h) carbonic anhydrase (CA) hCA IX and the less-explored cytosolic isoform, hCA XIII. All compounds exhibited potent inhibition of both isoforms, with KI values of <100 nM against hCA IX. Compound 4 b was the best inhibitor (KI =78.5 nM). All the compounds inhibited hCA XIII in the low-nanomolar to sub-micromolar range, with compound 4 b again showing the best inhibition (KI =76.3 nM). With compound 4 b as a lead, more-selective inhibitors of hCA IX and hCA XIII or dual hCA IX/XIII inhibitors might be developed.

Synthesis, crystal structure and Hirshfeld Surface analysis of benzamide derivatives of thiourea as potent inhibitors of α-glucosidase in-vitro.

Benzamide based structural analogues 1-15 were synthesized, and evaluated for α-glucosidase inhibition activity in vitro for the first time. Compounds 1-9 were found to be known, while compounds 10-15 were found to be new. However, to the best of our knowledge we are reporting α-glucosidase inhibitory activity of these bezamide derivatives of thiourea for the first time. Compounds 1, 3, 6-8, 10-14 were found to be potent inhibitors of α-glucosidase within IC50 range of 20.44-333.41 µM, in comparison to the standard inhibitor, acarbose (IC50 = 875.75 ± 2.08 µM). Mode of the enzyme inhibition was determined on the basis of kinetic studies which demonstrated that compounds 8, and 10 were non-competitive and competitive inhibitors of α-glucosidase enzyme, respectively. These compounds were also evaluated for their DPPH radical scavenging activity, and cytotoxicity against 3T3 mouse fibroblast cell lines. All synthesized compounds showed a significant to moderate DPPH radical scavenging activity and appeared to be non-cytotoxic except compound 9 which showed cytotoxicity against 3T3 normal mouse fibroblast cell lines. A single crystal X-ray and Hirshfeld Surface analysis of a representative compound is also presented.

Novel cyclic thiourea derivatives of aminoalcohols at the presence of AlCl3 catalyst as potent α-glycosidase and α-amylase inhibitors: Synthesis, characterization, bioactivity investigation and molecular docking studies.

The article is devoted to the targeted synthesis and study of cyclic thiourea and their various new derivatives as new organic compounds containing polyfunctional group in the molecule. First time the reaction of the corresponding synthesized pyrimidinethione with 1,2-epoxy-3-chlorpropane at the presence of AlCl3 catalyst in 75-80% yield alkyl-1-(3-chloro-2-hydroxypropyl)-4-alkyl-6-phenyl-2-thioxo-1,2,5,6- tetrahydropyrimidine-5-carboxylates. In the next stage, new cyclic thiourea derivatives of aminoalcohols were synthesised from the reaction of chlorinated derivatives of pyrimidinethiones with single amines and their structures were investigated by spectroscopic methods. In this study, a series of novel compounds were tested towards some metabolic enzymes including α-glycosidase (α-Gly) and α-amylase (α-Amy) enzymes. Novel compounds showed Kis in ranging of 10.43 ± 0.94-111.37 ± 13.25 µM on α-glycosidase and IC50 values in ranging of 14.38-106.51 µM on α-amylase. The novel cyclic thiourea derivatives of aminoalcohols had effective inhibition profiles against all tested metabolic enzymes. Binding affinity and inhibition mechanism of the most active compounds were detected with in silico studies and have shown that 2-Hydroxypropyl and butan-1-aminium moieties play a key role for inhibition of the enzymes.

α-ω Alkenyl-bis-S-Guanidine Thiourea Dihydrobromide Affects HeLa Cell Growth Hampering Tubulin Polymerization.

Cancer is going to be the first cause of mortality worldwide in the 21th century. It is considered a multifactorial disease that results from the combined influence of many genetic aberrations, leading to abnormal cell proliferation. As microtubules are strongly implicated in cellular growth, they represent an important target for cancer treatment. The well-known microtubule-targeting agents (MTAs) including paclitaxel, colchicine and vinca alkaloids are commonly used in the treatment of various cancers. However, adverse effects and drug resistance are major limitations in their clinical use. To find new candidates able to induce microtubule alteration with reduced toxic effects or drug resistance, we studied a small new series of derivatives that present imidazolinic, guanidinic, thioureidic and hydrazinic groups (1-9). All the compounds were tested for their antitumor activity against a panel of six tumoral cell models. In particular, compound 8 (nonane-1,9-diyl-bis-S-amidinothiourea dihydrobromide) showed the lowest IC50 value against HeLa cells, together with a low cytotoxicity for normal cells. This compound was able to induce the apoptotic mitochondrial pathway and inhibited tubulin polymerization with a similar efficacy to vinblastine and nocodazole. Taken together, these promising biological properties make compound 8 useful for the development of novel therapeutic approaches in cancer treatment.

Exploration of piperazine-derived thioureas as antibacterial and anti-inflammatory agents. In vitro evaluation against clinical isolates of colistin-resistant Acinetobacter baumannii.

A. baumannii is one of the most important multidrug-resistant microorganisms in hospital units. It is resistant to many classes of antibiotics and the development of new therapeutic strategies is necessary. The aim of this study was to evaluate the antibacterial activity of a set of piperazine-derived thioureas against 13 clinical strains of colistin-resistant A. baumannii. Six derivatives were identified to inhibit bacterial growth of 46% of the A. baumannii strains at low micromolar concentrations (Minimum Inhibitory Concentration from 1.56 to 6.25 µM). A common structural feature in most active compounds was the presence of a 3,5-bis-trifluoromethyl phenyl ring at the thiourea function. In addition, the ability of the compounds to inhibit production of nitric oxide (NO) was examined in RAW 264.7 murine macrophages, highlighting the potential of piperazine-derived thioureas as promising scaffolds for the design of new combined anti-bacterial/anti-inflammatory agents.

Design and synthesis of thiourea-based derivatives as Mycobacterium tuberculosis growth and enoyl acyl carrier protein reductase (InhA) inhibitors.

Tuberculosis remains the most deadly infectious disease worldwide due to the emergence of drug-resistant strains of Mycobacterium tuberculosis. Hence, there is a great need for more efficient treatment regimens. Herein, we carried out rational molecular modifications on the chemical structure of the urea-based co-crystallized ligand of enoyl acyl carrier protein reductase (InhA) (PDB code: 5OIL). Although this compound fulfills all structural requirements to interact with InhA, it does not inhibit the enzyme effectively. With the aim of improving the inhibition value, we synthesized thiourea-based derivatives by one-pot reaction of the amines with corresponding isothiocyanates. After the structural characterization using 1H NMR, 13C NMR, FTIR and HRMS, the obtained compounds were initially tested for their abilities to inhibit Mycobacterium tuberculosis growth. The results revealed that some compounds exhibited promising antitubercular activity, MIC values at 0.78 and 1.56 µg/mL, combined with low cytotoxicity. Moreover, the most active compounds were tested against latent as well as dormant forms of the bacteria utilizing nutrient starvation model and Mycobacterium tuberculosis infected macrophage assay. Enzyme inhibition assay against enoyl-acyl carrier protein reductase identified InhA as the important target of some compounds. Molecular docking studies were performed to correlate InhA inhibition data with in silico results. Finally, theoretical calculations were established to predict the physicochemical properties of the most active compounds.

Novel N-Cycloalkylcarbonyl-N'-arylthioureas: Synthesis, Design, Antifungal Activity and Gene Toxicity.

A synthesis method of novel N-cycloalkylcarbonyl-N'-arylthioureas was developed. It consists of sequential addition of equimolecular amounts of ammonium isothiocyanate and substituted anilines to cycloalkylcarbonyl chlorides. The identity and purity of products were confirmed by LC/MS spectra, their structure by elemental analysis, IR and 1 H-NMR spectra. Preliminary antimicrobial screening for standard microorganisms and molecular docking allowed to select several structures for antifungal and genetic toxicity studies. Conducted in vitro screening of 9 compounds for antifungal potential against 11 phytopathogenic fungi and three Phytophthora strains revealed that two N-(arylcarbamothioyl) cyclopropanecarboxamides at a concentration of 50 µg/ml exhibited activities comparable to the standard antifungal agent 'Cyproconazole'. Analysis of mutagenicity of novel thioureas using the Salmonella reverse mutagenicity assay ('Ames Test') showed a low gene-toxicity profile.