New phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamides as dual inhibitors against α-glucosidase and PTP-1B for the treatment of type 2 diabetes.

This study describes the design, synthesis, and evaluation of a novel series of phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamide derivatives (7a-l) as dual inhibitors of α-glucosidase and protein tyrosine phosphatase 1-B (PTB-1B). The latter enzymes are two important targets in the treatment of type 2 diabetes. The in vitro obtained data demonstrated that all title compounds 7a-l were more potent than the standard inhibitor acarbose against α-glucosidase while only four derivatives (7a, 7g, 7h, and 7h) were more potent than the standard inhibitor suramin against PTP-1B. Furthermore, these data showed that the most potent α-glucosidase inhibitor was compound 7i, with sixfold higher inhibitory activity than acarbose, and the most potent PTP-1B inhibitor was compound 7a with 3.5-fold higher inhibitory activity than suramin. Kinetic studies of compounds 7i and 7a revealed that they inhibited their target enzymes in a competitive mode. The docking study demonstrated that compounds 7i and 7a well occupied the active site pockets of α-glucosidase and PTP-1B, respectively. In silico pharmacokinetic and toxicity assays of the most potent compounds were performed, and the obtained results were compared with those of the standard inhibitors.

Synthesis and spectroscopic characterization of 13 C4 -labeled 4-cyano-2-oxobutyraldehyde semicarbazone: A metabolite of nitrofurazone.

Nitrofurazone usage in food-producing animals is prohibited in most countries, including the United States. Regulatory agencies regularly monitor its use in domestic, export/import animals' food products by measuring the semicarbazide (SEM) metabolite as a biomarker of nitrofurazone exposure. However, the use of SEM is controversial because it is also produced in food naturally and thus gives false positive results. A cyano-metabolite, 4-cyano-2-oxobutyraldehyde semicarbazone (COBS), is proposed as an alternate specific marker of nitrofurazone to distinguish nitrofurazone from treated or untreated animals. A synthetic method was developed to produce COBS via metallic hydrogenation of nitrofurazone. The product was isolated and characterized by one- and two-dimensional nuclear magnetic spectroscopy (NMR) experiments, Fourier-transform infrared spectroscopy (FT-IR), and mass spectrometry. The developed synthetic procedure was further extended to synthesize isotopically labeled 4-[13 C]-cyano-2-oxo- [2, 3, 4-13 C3 ]-butyraldehyde semicarbazone. Labeled COBS is useful as an internal standard for its quantification in food-producing animals. Thus, the developed method provides a possibility for its commercial synthesis to procure COBS. This is the first synthesis of the alternate specific marker metabolite of nitrofurazone for possible usage in regulatory analysis to solve a real-world problem.

Experimental and Computational Studies on the Interaction of DNA with Hesperetin Schiff Base CuII Complexes.

The interactions with calf thymus DNA (CT-DNA) of three Schiff bases formed by the condensation of hesperetin with benzohydrazide (HHSB or L1H3), isoniazid (HIN or L2H3), or thiosemicarbazide (HTSC or L3H3) and their CuII complexes (CuHHSB, CuHIN, and CuHTSC with the general formula [CuLnH2(AcO)]) were evaluated in aqueous solution both experimentally and theoretically. UV-Vis studies indicate that the ligands and complexes exhibit hypochromism, which suggests helical ordering in the DNA helix. The intrinsic binding constants (Kb) of the Cu compounds with CT-DNA, in the range (2.3-9.2) × 106, from CuHTSC to CuHHSB, were higher than other copper-based potential drugs, suggesting that π-π stacking interaction due to the presence of the aromatic rings favors the binding. Thiazole orange (TO) assays confirmed that ligands and Cu complexes displace TO from the DNA binding site, quenching the fluorescence emission. DFT calculations allow for an assessment of the equilibrium between [Cu(LnH2)(AcO)] and [Cu(LnH2)(H2O)]+, the tautomer that binds CuII, amido (am) and not imido (im), and the coordination mode of HTSC (O-, N, S), instead of (O-, N, NH2). The docking studies indicate that the intercalative is preferred over the minor groove binding to CT-DNA with the order [Cu(L1H2am)(AcO)] > [Cu(L2H2am)(AcO)] ≈ TO ≈ L1H3 > [Cu(L3H2am)(AcO)], in line with the experimental Kb constants, obtained from the UV-Vis spectroscopy. Moreover, dockings predict that the binding strength of [Cu(L1H2am)(AcO)] is larger than [Cu(L1H2am)(H2O)]+. Overall, the results suggest that when different enantiomers, tautomers, and donor sets are possible for a metal complex, a computational approach should be recommended to predict the type and strength of binding to DNA and, in general, to macromolecules.

The Importance of Substituent Position for Antibacterial Activity in the Group of Thiosemicarbazide Derivatives.

The search for new antibacterial compounds is still a huge challenge for scientists. Each new chemotherapy drug is not 100% effective when introduced into treatment. Bacteria quickly become resistant to known structures. One promising group of new compounds is thiosemicarbazides. In the presented work, we looked for the relationship between structure and antibacterial activity within the group of thiosemicarbazide derivatives. This is a continuation of our previous work. Here, we decided to check to what extent the position of the 3-methoxyphenyl substituent affects potency. We obtained new structures that differ in the positions of the substituent in the thiosemicarbazide skeleton. Based on the obtained results of the biological tests, it can be concluded that the substituent in position 1 of thiosemicarbazide derivatives significantly determines their activity. Generally, among the substituents used, trifluoromethylphenyl turned out to be the most promising. The MIC values for compounds with this substituent are 64 µg/mL towards Staphylococci sp. Using molecular docking, we tried to explain the mechanism behind the antibacterial activity of the tested compounds.

Schiff base 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide up-regulates the antioxidant status and inhibits the progression of Ehrlich solid tumor in mice.

Cisplatin is an approved cancer therapeutic drug used to treat many solid tumors but its accumulation in the kidney, which causes nephrotoxicity, limits its clinical use. Therefore, investigators seek new alternatives to cisplatin that may be more effective and/or safer. Thiosemicarbazides are of great significance due to their expected biological activity including anticancer activities. The aim of this work is the study of the antitumor effect of Schiff base 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide (HEPTS) on Ehrlich solid tumor-bearing mice in comparison to cancer therapeutic drug cisplatin. The experiment was run using sixty adult female Swiss albino mice. Mice were allocated into six groups (n = 10 mice). Healthy control, EAC control (untreated tumor), EAC + cisplatin, EAC + HEPTS, Healthy + HEPTS, and Healthy + solvent. After scarification, blood samples, liver organs, and solid tumors were collected. Tumor weights and volumes were registered. The concentrations of malondialdehyde (MDA), reduced glutathione (GSH), SOD, catalase (CAT), total antioxidant capacity (TAC), nitric oxide (NO), uric acid, creatinine, and urea were assessed. Median survival time (MST) and the percentage increase in lifespan (%ILS) were also calculated. Treatment of tumorized mice with HEPTS significantly reduced both tumor volume and weight while it significantly increased the MST, antioxidant marks and prolonged the %ILS. It also, significantly reduced MAD, creatinine, urea, uric acid, and NO levels. Compared to cisplatin, HEPTS effects were better. Our results recommend HEPTS as one of the probable cisplatin-alternatives for tumor treatment after more validation.

Thiosemicarbazide binds with the dicopper center in the competitive inhibition of mushroom tyrosinase enzyme: Synthesis and molecular modeling of theophylline analogues.

Theophylline is long known for its anti-ageing and anti-oxidative properties. Moreover, Tyrosinase is a crucial enzyme that regulates the melanin synthetic pathway, which is involved in various physiological metabolic processes including aging. The current paper describes the synthesis of various heterocyclic systems coupled with theophylline moiety along with their tyrosinase inhibition activity in view to identify the potent nucleus. Around 19 compounds were synthesized and screened for enzyme inhibition. Based on the current study, it is suggested that compound 18 having thiosemicarbazide has strong enzyme inhibition potential. The enzyme kinetics and docking studies provide important insights into how the compound interacts with the mushroom tyrosinase active site. The work will provide clue to developing new, potent tyrosinase inhibitors for drug development.

4-Arylthiosemicarbazide derivatives as a new class of tyrosinase inhibitors and anti-Toxoplasma gondii agents.

We report herein anti-proliferation effects of 4-arylthiosemicarbazides, with a cyclopentane substitution at N1 position, on highly virulent RH strain of Toxoplasma gondii. Among them, the highest in vitro anti-Toxoplasma activity was found with the meta-iodo derivative. Further experiments demonstrated inhibitory effects of thiosemicarbazides on tyrosinase (Tyr) activity, and good correlation was found between percentage of Tyr inhibition and IC50Tg. To confirm the concept that thiosemicarbazides are able to disrupt tyrosine metabolism in Toxoplasma tachyzoites, the most potent Tyr inhibitors were tested for their efficacy of T. gondii growth inhibition. All of them significantly reduced the number of tachyzoites in the parasitophorous vacuoles (PVs) compared to untreated cells, as well as inhibited tachyzoites growth by impeding cell division. Collectively, these results indicate that compounds with the thiosemicarbazide scaffold are able to disrupt tyrosine metabolism in Toxoplasma tachyzoites by deregulation of their crucial enzyme tyrosine hydroxylase (TyrH).

Design, synthesis and evaluation of carbazole derivatives as potential antimicrobial agents.

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5-2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure-activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.

Electrochemiluminescence biosensor for microRNA determination based on AgNCs@MoS2 composite with (AuNPs-Semicarbazide)@Cu-MOF as coreaction accelerator.

A novel electrochemiluminescence (ECL) biosensor was fabricated for miRNA-162a detection by using silver nanoclusters/molybdenum disulfide (AgNCs@MoS2) as an ECL material, peroxodisulfate (S2O82-) as a co-reactant, and semicarbazide (Sem) as a co-reaction accelerator. Firstly, hairpin probe Ha modified on AgNCs@MoS2/GCE was unfolded based on its hybridization with target microRNA. Then, the unfolded Ha can further be hybridized with another hairpin DNA of Hb on (AuNPs-semicarbazide)@Cu-MOF, resulting in the release of target microRNA, which further causes a cyclic hybridization. This creates more (AuNPs-semicarbazide)@Cu-MOF on the electrode surface, achieving cyclic hybridization signal amplification. Strikingly, due to the presence of Sem, accelerating the reduction of S2O82- and resulting in the generation of more oxidant intermediates of SO42-, the amount of excited states of Agincreases to further amplify the ECL signal. The biosensor exhibited high sensitivity with a low LOD of 1.067 fM, indicating that the introduction of co-reaction accelerators can provide an effective method for signal amplification. The applicability of this method was assessed by investigating the effect of Pb(II) ion on miRNA-162a expression level in maize seedling leaves. A novel electrochemiluminescence biosensor was fabricated for miRNA-162a detection by using silver nanoclusters/molybdenum disulfide as an ECL material, peroxodisulfate as a co-reactant, and semicarbazide as a co-reaction accelerator.

Synthesis of new 1,2,4-triazole-(thio)semicarbazide hybrid molecules: Their tyrosinase inhibitor activities and molecular docking analysis.

Tyrosinase inhibition is very important in controlling melanin synthesis. If melanin synthesis is not controlled in metabolism, an unwanted increase in melanin synthesis occurs. As melanin plays a role in the formation of skin color, its unusual levels cause some skin disorders such as pregnancy scars, age spots, and especially skin cancer (melanoma). However, the tyrosinase activity is also related to Parkinson's disease and some neurodegenerative diseases. For all these reasons, the medicinal as well as the cosmetic industries focus on research on tyrosinase inhibitors for the treatment of skin disorders and some neurodegenerative diseases. In this study, 32 new 1,2,4-triazole-(thio)semicarbazide hybrid molecules (6a-p and 7a-p) were synthesized, starting from 4-amino-1-pentyl-3-phenyl-1H-1,2,4-triazole-5(4H)-one. These compounds were evaluated for their inhibitory activity against mushroom tyrosinase. The results indicated that 6h, 6m, 6n, and 6p exhibited the most effective inhibitory activity, with IC50 values of 0.00162 ± 0.0109, 0.00166 ± 0.0217, 0.00165 ± 0.019, and 0.00197 ± 0.0063 µM, respectively, compared with kojic acid as the reference drug (IC50 = 14.09 ± 0.02 µM). Also, molecular docking analyses were performed to suggest possible binding poses for the ligands. As a result, derivatives 6h, 6m, 6n, and 6p can be used as promising tyrosinase inhibitor candidates in the medicinal, cosmetics, or food industries.

Optimized Synthesis of New Thiosemicarbazide Derivatives with Tuberculostatic Activity.

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.

Thiosemicarbazide Derivatives Decrease the ATPase Activity of Staphylococcus aureus Topoisomerase IV, Inhibit Mycobacterial Growth, and Affect Replication in Mycobacterium smegmatis.

Compounds targeting bacterial topoisomerases are of interest for the development of antibacterial agents. Our previous studies culminated in the synthesis and characterization of small-molecular weight thiosemicarbazides as the initial prototypes of a novel class of gyrase and topoisomerase IV inhibitors. To expand these findings with further details on the mode of action of the most potent compounds, enzymatic studies combined with a molecular docking approach were carried out, the results of which are presented herein. The biochemical assay for 1-(indol-2-oyl)-4-(4-nitrophenyl) thiosemicarbazide (4) and 4-benzoyl-1-(indol-2-oyl) thiosemicarbazide (7), showing strong inhibitory activity against Staphylococcus aureus topoisomerase IV, confirmed that these compounds reduce the ability of the ParE subunit to hydrolyze ATP rather than act by stabilizing the cleavage complex. Compound 7 showed better antibacterial activity than compound 4 against clinical strains of S. aureus and representatives of the Mycobacterium genus. In vivo studies using time-lapse microfluidic microscopy, which allowed for the monitoring of fluorescently labelled replisomes, revealed that compound 7 caused an extension of the replication process duration in Mycobacterium smegmatis, as well as the growth arrest of bacterial cells. Despite some similarities to the mechanism of action of novobiocin, these compounds show additional, unique properties, and can thus be considered a novel group of inhibitors of the ATPase activity of bacterial type IIA topoisomerases.

Synthesis and Antinociceptive Effect of Some Thiazole-Piperazine Derivatives: Involvement of Opioidergic System in the Activity.

In this study, we aimed to design and synthesize novel molecules carrying both the thiazole and piperazine rings in their structures and to investigate their antinociceptive activity. Targeted compounds were obtained by reacting thiosemicarbazide derivative and appropriate 2-bromoacetophenone in ethanol. The structures of the obtained compounds were determined using data from various spectroscopic methods (IR, 1H-NMR, 13C-NMR, and LCMSMS). Experimental data from in vivo tests showed that test compounds 3a-3c, 3f, and 3g (50 mg/kg) significantly prolonged reaction times of animals in tail-clip and hot-plate tests compared to the controls, indicating that these compounds possess centrally mediated antinociceptive activities. Furthermore, these compounds reduced the number of writhing behaviors in the acetic acid-induced writhing tests, showing that the compounds also possess peripheral antinociceptive activity. In the mechanistic studies, naloxone pre-treatments abolished the antinociceptive activities of compounds 3a-3c, 3f, and 3g, indicating that opioidergic mechanisms were involved in their antinociceptive effects. Molecular docking studies demonstrating significant interactions between the active compounds and µ- and δ-opioid receptor proteins supported the pharmacological findings. This study is the first showing that molecules designed to bear thiazole and piperazine moieties together on their structure exert centrally and peripherally mediated antinociceptive effects by activating the opioid system.

In Vivo Targeting Using Arylboronate/Nopoldiol Click Conjugation.

Bioorthogonal click reactions yielding stable and irreversible adducts are in high demand for in vivo applications, including in biomolecular labeling, diagnostic imaging, and drug delivery. Previously, we reported a novel bioorthogonal "click" reaction based on the coupling of ortho-acetyl arylboronates and thiosemicarbazide-functionalized nopoldiol. We now report that a detailed structural analysis of the arylboronate/nopoldiol adduct by X-ray crystallography and 11B NMR reveals that the bioorthogonal reactants form, unexpectedly, a tetracyclic adduct through the cyclization of the distal nitrogen into the semithiocarbazone leading to a strong B-N dative bond and two new 5-membered rings. The cyclization adduct, which protects the boronate unit against hydrolytic breakdown, sheds light on the irreversible nature of this polycondensation. The potential of this reaction to work in a live animal setting was studied through in vivo capture of fluorescently labeled molecules in vivo. Arylboronates were introduced into tissues through intradermal injection of their activated NHS esters, which react with amines in the extracellular matrix. Fluorescently labeled nopoldiol molecules were administered systemically and were efficiently captured by the arylboronic acids in a location-specific manner. Taken together, these in vivo proof-of-concept studies establish arylboronate/nopoldiol bioorthogonal chemistry as a candidate for wide array of applications in chemical biology and drug delivery.

Polyethylene glycol (PEG-400) promoted one-pot, five-component synthesis of (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)-4-oxothiazol-5(4H)-ylidene)acetates.

A facile, inexpensive and eco-friendly synthesis of functionalised (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)14-oxothiazol-5(4H)-ylidene)acetates has been developed via one-pot five-component approach. The title compounds were synthesized by the reaction of anilines, 3-chloropentane-2,4-dione, ammoniumthiocyanate, thiosemicarbazide and dialkylacetylene dicarboxylate using polyethylene glycol as green and recyclable solvent. The domino reaction proceeded smoothly in good-to-excellent yields.

Design, Synthesis, Biological Evaluation and Inhibition Mechanism of 3-/4-Alkoxy Phenylethylidenethiosemicarbazides as New, Potent and Safe Tyrosinase Inhibitors.

Tyrosinase plays important roles in many different disease related processes, and the development of its inhibitors is particularly important in biotechnology. In this study, thirty-nine 3-/4-alkoxyphenylethylidenethiosemicarbazides were synthesized as novel tyrosinase inhibitors based on structure-based molecular design. Our experimental results demonstrated that thirty-one of them possess remarkable tyrosinase inhibitory activities with IC50 value below 1 µM, and 5a, 6e, 6g and 6t did not display any toxicity to 293T cell line at the concentration of 1000 µmol/L. According to the inhibitory activities, several compounds were selected for detail investigation on the structure-activity relationships (SARs), mechanisms of enzyme inhibition, inhibitory kinetics and cytotoxicity. In particular, the interaction between the selected inhibitors and the active center of tyrosinase was considered and discussed in detail based on their structural characteristics. Taken together, the results presented here demonstrated that the newly designed compounds are promising candidates for the treatment of tyrosinase-related disorders and further development of them may have significant contribution in biomedical science.

Synthesis and antituberculosis activity of new acylthiosemicarbazides designed by structural modification.

Acylthiosemicarbazides 8a-n were designed by structural modification of lead Compound 7. The syntheses of 8a-n involve a five-step procedure starting from carboxylic acids. Compounds 8a-n were tested against three Mycobacterium tuberculosis strains to measure their inhibitory antituberculosis activities. These activities could be explained according to the presence or absence of the chlorine substituent in the aromatic ring of the amide joined to the thiosemicarbazide core. Thiosemicarbazide derivative 8n is a candidate for the development of novel antitubercular agents. Ongoing studies are focused on exploring the mechanism by which these compounds inhibit M. tuberculosis cell growth.

Synthesis and Anthelmintic Activity of New Thiosemicarbazide Derivatives-A Preliminary Study.

Parasitic infections caused by different species of intestinal helminths still poses a threat to public health. There is a need to search for new, effective anthelmintic drugs. A series of novel thiosemicarbazides were synthesized and evaluated for their in vitro anthelmintic activity. The preliminary results showed that the most of synthesized compounds were very active. 4-Phenyl-1-[(1-methyl-4-nitroimidazol-2-yl)carbonyl]thiosemicarbazide and 4-(3-chlorophenyl)-1-[(1-methyl-4-nitroimidazol-2-yl)carbonyl]thiosemicarbazide showed a 100% mortality of nematodes and a high anthelmintic activity in both tested concentrations.

Antibacterial Activity of Fluorobenzoylthiosemicarbazides and Their Cyclic Analogues with 1,2,4-Triazole Scaffold.

The development of drug-resistant bacteria is currently one of the major challenges in medicine. Therefore, the discovery of novel lead structures for the design of antibacterial drugs is urgently needed. In this structure-activity relationship study, a library of ortho-, meta-, and para-fluorobenzoylthiosemicarbazides, and their cyclic analogues with 1,2,4-triazole scaffold, was created and tested for antibacterial activity against Gram-positive bacteria strains. While all tested 1,2,4-triazoles were devoid of potent activity, the antibacterial response of the thiosemicarbazides was highly dependent on substitution pattern at the N4 aryl position. The optimum activity for these compounds was found for trifluoromethyl derivatives such as 15a, 15b, and 16b, which were active against both the reference strains panel, and pathogenic methicillin-sensitive and methicillin-resistant Staphylococcus aureus clinical isolates at minimal inhibitory concentrations (MICs) ranging from 7.82 to 31.25 µg/mL. Based on the binding affinities obtained from docking, the conclusion can be reached that fluorobenzoylthiosemicarbazides can be considered as potential allosteric d-alanyl-d-alanine ligase inhibitors.

Docking and QSAR of Aminothioureas at the SARS-CoV-2 S-Protein-Human ACE2 Receptor Interface.

Docking of over 160 aminothiourea derivatives at the SARS-CoV-2 S-protein-human ACE2 receptor interface, whose structure became available recently, has been evaluated for its complex stabilizing potency and subsequently subjected to quantitative structure-activity relationship (QSAR) analysis. The structural variety of the studied compounds, that include 3 different forms of the N-N-C(S)-N skeleton and combinations of 13 different substituents alongside the extensive length of the interface, resulted in the failure of the QSAR analysis, since different molecules were binding to different parts of the interface. Subsequently, absorption, distribution, metabolism, and excretion (ADME) analysis on all studied compounds, followed by a toxicity analysis using statistical models for selected compounds, was carried out to evaluate their potential use as lead compounds for drug design. Combined, these studies highlighted two molecules among the studied compounds, i.e., 5-(pyrrol-2-yl)-2-(2-methoxyphenylamino)-1,3,4-thiadiazole and 1-(cyclopentanoyl)-4-(3-iodophenyl)-thiosemicarbazide, as the best candidates for the development of future drugs.