Antifungal effect of 4-arylthiosemicarbazides against Candida species. Search for molecular basis of antifungal activity of thiosemicarbazide derivatives

Synthesis and Biological Evaluation of New Compounds with Nitroimidazole Moiety

Heterocyclic compounds, particularly those containing azole rings, have shown extensive biological activity, including anticancer, antibacterial, and antifungal properties. Among these, the imidazole ring stands out due to its diverse therapeutic potential. In the presented study, we designed and synthesized a series of imidazole derivatives to identify compounds with high biological potential. We focused on two groups: thiosemicarbazide derivatives and hydrazone derivatives. We synthesized these compounds using conventional methods and confirmed their structures via nuclear magnetic resonance spectroscopy (NMR), MS, and elemental analysis, and then assessed their antibacterial and antifungal activities in vitro using the broth microdilution method against Gram-positive and Gram-negative bacteria, as well as Candida spp. strains. Our results showed that thiosemicarbazide derivatives exhibited varied activity against Gram-positive bacteria, with MIC values ranging from 31.25 to 1000 µg/mL. The hydrazone derivatives, however, did not display significant antibacterial activity. These findings suggest that structural modifications can significantly influence the antimicrobial efficacy of imidazole derivatives, highlighting the potential of thiosemicarbazide derivatives as promising candidates for further development in antibacterial therapies. Additionally, the cytotoxic activity against four cancer cell lines was evaluated. Two derivatives of hydrazide-hydrazone showed moderate anticancer activity.

Evaluation of the antidermatophytic activity of potassium salts of N-acylhydrazinecarbodithioates and their aminotriazole-thione derivatives

Nowadays, dermatophyte infections are relatively easy to cure, especially since the introduction of orally administered antifungals such as terbinafine and itraconazole. However, these drugs may cause side effects due to liver damage or their interactions with other therapeutics. Hence, the search for new effective chemotherapeutics showing antidermatophyte activity seems to be the urge of the moment. Potassium salts of N-acylhydrazinecarbodithioates are used commonly as precursors for the synthesis of biologically active compounds. Keeping that in mind, the activity of a series of five potassium N-acylhydrazinecarbodithioates (1a-e) and their aminotriazole-thione derivatives (2a-e) was evaluated against a set of pathogenic, keratinolytic fungi, such as Trichophyton ssp., Microsporum ssp. and Chrysosporium keratinophilum, but also against some Gram-positive and Gram-negative bacteria. All tested compounds were found non-toxic for L-929 and HeLa cells, with the IC30 and IC50 values assessed in the MTT assay above 128 mg/L. The compound 5-amino-3-(naphtalene-1-yl)-4,5-dihydro-1H-1,2,4-triazole-5-thione (2d) was found active against all fungal strains tested. Scanning Electron Microscopy (SEM) revealed inhibition of mycelium development of Trichophyton rubrum cultivated on nail fragments and treated with 2d 24 h after infection with fungal spores. Transmission Electron Microscopy (TEM) observation of mycelium treated with 2d showed ultrastructural changes in the morphology of germinated spores. Finally, the RNA-seq analysis indicated that a broad spectrum of genes responded to stress induced by the 2d compound. In conclusion, the results confirm the potential of N-acylhydrazinecarbodithioate derivatives for future use as promising leads for new antidermatophyte agents development.

N-Substituted 2-(Benzenosulfonyl)-1-Carbotioamide Derivatives Exert Antimicrobial and Cytotoxic Effects via Aldehyde Dehydrogenase Pathway: Synthesis, In Silico and In Vitro Studies

A series of N-Substituted 2-(benzenosulfonyl)-1-carbotioamide derivatives (WZ1-WZ4) were synthesized and characterized using spectral methods. A comprehensive activity study was performed for each compound. All compounds were tested for antibacterial activity. Moreover, in silico studies were carried out to determine the anticancer potential of the designed WZ1-WZ4 ligands. Based on molecular docking, aldehyde dehydrogenase was selected as a molecular target. The obtained data were compared with experimental data in vitro tests. Novel hybrids of the thiosemicarbazide scaffold and sulfonyl groups may have promising anticancer activity via the aldehyde dehydrogenase pathway. The best candidate for further studies appears to be WZ2, due to its superior selectivity in comparison to the other tested compounds.

Synthesis of novel coumarin-based thiosemicarbazones and their implications in diabetic management via in-vitro and in-silico approaches

Diabetes mellitus has a high prevalence rate and it has been deemed a severe chronic metabolic disorder with long-term complications. This research aimed to identify compounds that could potentially inhibit the vital metabolic enzyme α-glucosidase and thereby exert an anti-hyperglycemic effect. The main goal was to establish an effective approach to control diabetes. To proceed with this study, a series of novel coumarin-derived thiosemicarbazones 3a-3m was synthesized and examined using a variety of spectroscopic methods. Moreover, all the compounds were subjected to α-glucosidase inhibition bioassay to evaluate their antidiabetic potential. Fortunately, all the compounds exhibited several folds potent α-glucosidase inhibitory activities with IC50 values ranging from 2.33 to 22.11 µM, in comparison to the standard drug acarbose (IC50 = 873.34 ± 1.67 µM). The kinetic studies of compound 3c displayed concentration-dependent inhibition. Furthermore, the binding modes of these molecules were elucidated through a molecular docking strategy which depicted that the thiosemicarbazide moiety of these molecules plays a significant role in the interaction with different residues of the α-glucosidase enzyme. However, their conformational difference is responsible for their varied inhibitory potential. The molecular dynamics simulations suggested that the top-ranked compounds (3c, 3g and 3i) have a substantial effect on the protein dynamics which alter the protein function and have stable attachment in the protein active pocket. The findings suggest that these molecules have the potential to be investigated further as novel antidiabetic medications.

Synthesis, spectroscopic characterization, density functional theory study, antimicrobial and antioxidant activities of curcumin and alanine-curcumin Schiff base

In this work, a novel Schiff-base derived from curcumin and L-Alanine was synthesized under microwave conditions in excellent yield. The structural characterization has been carried out from their elemental analyses, FTIR, UV-Vis and 13C-NMR and 1H-NMR spectral techniques. The Schiff base (Cur-Ala) and curcumin (Cur) have been screened for their antimicrobial activity toward some pathogens clinically important microorganisms: Bacillus subtilis, Escherichia coli and Staphylococcus aureus, Aspergillus niger and Candida albicans. Result found that the Schiff base was more active than the curcumin. The antibacterial and antifungal activities of Cur-Ala can be attributed to its greatest dipole moment, as shown by theoretical calculations. Also, the antioxidant activity of Schiff base and curcumin were studied by DPPH, cupric ion reducing antioxidant capacity and o-phenanthroline techniques. Results indicate that Cur-Ala and Cur show more antioxidant activities than the standard antioxidants (BHT and BHA). Quantum chemical parameter calculations of Cur-Ala and Cur have been investigated by DFT using B3LYP/6-31G (d,p) basis set method to calculate the optimized structure, atomic charges, MESP, global reactivity descriptors and thermomolecular proprieties of both molecules.Communicated by Ramaswamy H. Sarma.

Novel Design of Citral-Thiourea Derivatives for Enhancing Antifungal Potential against Colletotrichum gloeosporioides

Although much progress has been made in developing botanical fungicides to combat fungal diseases in crops, there remains a great need to improve the efficiency and long-term safety of these fungicides. This study proposes a novel strategy for designing citral-thiourea derivatives that feature such desirable properties. The motivation of the work herein was to enhance the antifungal activity of citral against C. gloeosprioides by exploiting the synergistic effect that arises from combining citral and thiourea compounds, thereby producing citral-thiourea derivatives that exhibit good long-term safety. The results revealed that the generated compounds e1, e3, e6, e18, and g showed remarkable antifungal activities against C. gloeosprioides, with corresponding EC50 values reaching 0.16, 1.66, 1.37, 4.76, and 4.60 mg/L, respectively, showing that the compounds significantly outperformed both the positive control kresoxim-methyl and the commercially available fungicide carbendazim. Furthermore, compound g showed stronger protective efficacy against C. gloeosprioides than carbendazim on mango fruit at 25 mg/L. Investigating the preliminary structure-activity relationship (SAR) of the compounds also revealed that the citral-thiourea derivatives exhibited higher antifungal activities against C. gloeosprioides compared to citral and thiourea compounds. This reinforcement of antifungal activity observed in the derivatives was found to be attributable to the two characteristics of low molecular size and the presence of a fluorine atom in the meta-position of the benzene ring. Beyond this, it was determined from QSAR that two molecular descriptors (the Kier-Hall index (order 3) and Tot dipole of the molecules) were negatively related to the antifungal activity of the citral-thiourea derivatives, while one other (the maximum resonance energy of a C-H bond) was positively related to their antifungal activity. More importantly, the citral-thiourea derivatives with high antifungal activities (i.e., compounds e1, e3, e6, e14, e15, e18, and g) exhibited negligible cytotoxicity to LO2 and HEK293T cell lines. The antifungal mechanism of the generated citral-thiourea derivatives was investigated by scanning electron microscopy (SEM) and relative conductivity. The derivatives were found to affect mycelial morphology and increase fungal cell membrane permeability, thereby resulting in the destruction of fungal cell membranes. These promising results provide novel insights into the study and potential application value of citral-thiourea derivatives as high-efficiency antifungal agents against C. gloeosprioides.

Bis-pharmacophore of cinnamaldehyde-clubbed thiosemicarbazones as potent carbonic anhydrase-II inhibitors

Here, we report the synthesis, carbonic anhydrase-II (CA-II) inhibition and structure–activity relationship studies of cinnamaldehyde-clubbed thiosemicarbazones derivatives. The derivatives showed potent activities in the range of 10.3 ± 0.62–46.6 ± 0.62 µM. Among all the synthesized derivatives, compound 3n (IC₅₀ = 10.3 ± 0.62 µM), 3g (IC₅₀ = 12.1 ± 1.01 µM), and 3h (IC₅₀ = 13.4 ± 0.52 µM) showed higher inhibitory activity as compared to the standard inhibitor, acetazolamide. Furthermore, molecular docking of all the active compounds was carried out to predict their behavior of molecular binding. The docking results indicate that the most active hit (3n) specifically mediate ionic interaction with the Zn ion in the active site of CA-II. Furthermore, the The199 and Thr200 support the binding of thiosemicarbazide moiety of 3n, while Gln 92 supports the interactions of all the compounds by hydrogen bonding. In addition to Gln92, few other residues including Asn62, Asn67, The199, and Thr200 play important role in the stabilization of these molecules in the active site by specifically providing H-bonds to the thiosemicarbazide moiety of compounds. The docking score of active hits are found in range of − 6.75 to − 4.42 kcal/mol, which indicates that the computational prediction correlates well with the in vitro results.

Design, synthesis, and in vitro evaluation of thiosemicarbazone derivatives as anti-filarial agents

Effective macrofilaricidal drugs are not commercially available, and in an endeavour to find out new macrofilaricidal agents, in this research work, thiosemicarbazone derivatives have been prepared and tested against adult Setaria digitata, a cattle filarial parasite, as a model nematode for the filarial parasite, Wuchereria bancrofti. Lipinski and Veber rules have been used to design these molecules and found out that all the designed molecules show drug-like molecular properties. The in vitro anti-filarial potential of thiosemicarbazones against S. digitata was carried out using worm motility and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) reduction colorimetric assays at 100 μg/ml concentration for the incubation period of 24 h. The standard drugs used at present for filaria, Albendazole, Ivermectin and Diethylcarbamazine were not able to kill the adult filarial worms effectively. In contrast, phenyl thiosemicarbazones with trifluoromethyl substitution at 3rd and 4th positions, 2-pyrrolyl, and isatinyl made the adult worms immotile and also showed 69%-83% inhibition in formazan formation an indicator of non viability.

Synthesis, molecular modelling and antibacterial activity of 4-aryl-thiosemicarbazides

N-Substituted phenyl/cyclohexyl-2-(pyridine-4-carbonyl) hydrazine-1-carbothioamides (2a–r) were synthesized, characterized by spectral and analytical data. The compounds were evaluated for antibacterial activity by the disc diffusion method. Most of the compounds showed activity against Gram-positive bacteria. Compound 2h with 4-Sulfapyrimidine phenyl substitution was found to be the most promising candidate, active against Gram-positive and methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentration (MIC) of (2–7 μg/mL). From the docking study, we predicted that compounds (2r, 2g, 2h, 2o, 2p and 2e) possess better antibacterial activity by having a good binding affinity with target protein and they could be used as potential drugs as antimicrobials. Amongst all the docked compounds, the compound 2h presented near binding affinity & interaction docking score with DNA gyrase enzymes with reference to ciprofloxacin.

Computational Drug Repurposing Resources and Approaches for Discovering Novel Antifungal Drugs against Candida albicans N-Myristoyl Transferase

Candida albicans is a yeast that is an opportunistic fungal pathogen and also identified as ubiquitous polymorphic species that is mainly linked with major fungal infections in humans, particularly in the immunocompromised patients including transplant recipients, chemotherapy patients, HIV-infected patients as well as in low-birth-weight infants. Systemic Candida infections have a high mortality rate of around 29 to 76%. For reducing its infection, limited drugs are existing such as caspofungin, fluconazole, terbinafine, and amphotericin B, etc. which contain unlikable side effects and also toxic. This review intends to utilize advanced bioinformatics technologies such as Molecular docking, Scaffold hopping, Virtual screening, Pharmacophore modeling, Molecular dynamics (MD) simulation for the development of potentially new drug candidates with a drug-repurpose approach against Candida albicans within a limited time frame and also cost reductive.

Combined in vitro and in silico approach to evaluate the inhibitory potential of an underutilized allium vegetable and its pharmacologically active compounds on multidrug resistant Candida species

Candida infections and related mortality have become a challenge to global health. Nontoxic and natural bioactive compounds from plants are regarded as promising candidates to inhibit these multidrug resistant strains. In the present study, in vitro assays and in silico molecular docking approach was combined to evaluate the inhibitory effect of crude extracts from Allium ampeloprasum and its variety A. porrum on Candida pathogens. Phytochemical screening revealed the presence of phenolic acids and flavonoids in higher quantity. Spectral studies of the extracts support the presence of phenols, flavonoids and organosulfur compounds. Aqueous extract of A. ampeloprasum showed a total antioxidant capacity of 68 ± 1.7 mg AAE/ g and an IC50 value of 0.88 ± 2.1 mg/ml was obtained for DPPH radicals scavenging assay. C. albicans were highly susceptible (19.9 ± 1.1 mm) when treated with aqueous A. ampeloprasum extract. Minimum inhibitory concentrations were within the range of 19-40 μg/ml and the results were significant (p ≤ 0.05). In silico molecular docking studies demonstrated that bioactive phytocompounds of A. ampeloprasum and A. porrum efficiently interacted with the active site of Secreted aspartyl proteinase 2 enzyme that is responsible for the virulence of pathogenic yeasts. Rosmarinic acid and Myricetin exhibited low binding energies and higher number of hydrogen bond interactions with the protein target. Thus the study concludes that A. ampeloprasum and A. porrum that remain as underutilized vegetables in the Allium genus are potential anti-candida agents and their pharmacologically active compounds must be considered as competent candidates for drug discovery.

Discovery of thiosemicarbazone derivatives as effective New Delhi metallo-β-lactamase-1 (NDM-1) inhibitors against NDM-1 producing clinical isolates

New Delhi metallo-β-lactamase-1 (NDM-1) is capable of hydrolyzing nearly all β-lactam antibiotics, posing an emerging threat to public health. There are currently less effective treatment options for treating NDM-1 positive “superbug”, and no promising NDM-1 inhibitors were used in clinical practice. In this study, structure–activity relationship based on thiosemicarbazone derivatives was systematically characterized and their potential activities combined with meropenem (MEM) were evaluated. Compounds 19bg and 19bh exhibited excellent activity against 10 NDM-positive isolate clinical isolates in reversing MEM resistance. Further studies demonstrated compounds 19bg and 19bh were uncompetitive NDM-1 inhibitors with Ki = 0.63 and 0.44 μmol/L, respectively. Molecular docking speculated that compounds 19bg and 19bh were most likely to bind in the allosteric pocket which would affect the catalytic effect of NDM-1 on the substrate meropenem. Toxicity evaluation experiment showed that no hemolysis activities even at concentrations of 1000 mg/mL against red blood cells. In vivo experimental results showed combination of MEM and compound 19bh was markedly effective in treating infections caused by NDM-1 positive strain and prolonging the survival time of sepsis mice. Our finding showed that compound 19bh might be a promising lead in developing new inhibitor to treat NDM-1 producing superbug.

Synthesis of Cobalt Hydroxide Nano-flakes Functionalized with Glutamic Acid and Conjugated with Thiosemicarbazide for Anticancer Activities Against Human Breast Cancer Cells

In recent years, researchers were attracted to nanomaterials components for their potential role in cancer treatment. This study aimed to develop a novel and biocompatible cobalt hydroxide (Co(OH)₂) nano-flakes that is functionalized by glutamic acid (Glu) and conjugated to thiosemicarbazide (TSC) for anticancer activities against human breast cancer MCF-7 cells. Physico-chemical properties of the Co(OH)₂@Glu-TSC nanomaterial are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, and Fourier-transform infrared (FT-IR) spectroscopy. MTT assay, flow cytometry, and caspase-3 activity analysis used for evaluating anticancer properties of the Co(OH)₂@Glu-TSC nanomaterial. The MTT assay result showed cellular uptake of Co(OH)₂@Glu-TSC and cell viability loss in a concentration-dependent. Results of flow cytometry and caspase-3 activity analysis indicated the stimulation of apoptosis through an increase in Caspase-3 and nucleus fragmentation. In general, our findings indicate the anticancer activities of Co(OH)₂@Glu-TSC nanomaterial and so it can be considered as a new treatment for breast cancer. However, further in vivo studies are required to evaluate the accumulation of Co(OH)₂@Glu-TSC nanomaterial in healthy organs, such as the liver, kidneys, brain, and testes, and potential toxic effects.

Investigation of thiosemicarbazide free or within chitosan nanoparticles in a murine model of vulvovaginal candidiasis

Vulvovaginal candidiasis is a serious health problem affecting numerous women around the world. Its treatment is based on antifungals which may not provide an effective cure because of the resistance presented by its etiological pathogens Candida spp. Candida albicans is the most prevalent species related to vulvovaginal candidiasis. Here, we evaluated the in vivo antifungal potential of thiosemicarbazide and thiosemicarbazide encapsulated within chitosan nanoparticles in a murine model of vulvovaginal candidiasis. The results demonstrated the antifungal capacity of free or nanoencapsulated thiosemicarbazide within chitosan to reduce the fungal load in the vaginal tissue of infected mice. In addition, histological analyses indicated the absence or a mild to moderate infection in thiosemicarbazide-treated groups. Statistical tests confirmed the existence of significant differences between the treated and the control groups. Therefore, our results suggest a potential application of thiosemicarbazide and encapsulated thiosemicarbazide as an alternative vulvovaginal candidiasis therapy.

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.

Synthesis, bioactivity and binding energy calculations of novel 3-ethoxysalicylaldehyde based thiosemicarbazone derivatives

In recent decade, the entrance of α-N-heterocyclic thiosemicarbazones derivates (Triapne, COTI-2 and DpC) in clinical trials for cancer and HIV-1 has vastly increased the interests of medicinal chemists towards this class of organic compounds. In the given study, a series of eighteen new (3a-r) 3-ethoxy salicylaldehyde-based thiosemicarbazones (TSC), bearing aryl and cycloalkyl substituents, were synthesized and assayed for their pharmacological potential against carbonic anhydrases (hCA I and hCA II), cholinesterases (AChE and BChE) and α-glycosidase. The hCA I isoform was inhibited by these novel 3-ethoxysalicylaldehyde thiosemicarbazone derivatives (3a-r) in low nanomolar levels, the Ki of which differed between 144.18 ± 26.74 and 454.92 ± 48.32 nM. Against the physiologically dominant isoform hCA II, the novel compounds demonstrated K_is varying from 110.54 ± 14.05 to 444.12 ± 36.08 nM. Also, these novel derivatives (3a-r) effectively inhibited AChE, with Ki values in the range of 385.38 ± 45.03 to 983.04 ± 104.64 nM. For BChE was obtained with Ki values in the range of 400.21 ± 35.68 to 1003.02 ± 154.27 nM. For α-glycosidase the most effective Ki values of 3l, 3n, and 3q were with Ki values of 12.85 ± 1.05, 16.03 ± 2.84, and 19.16 ± 2.66 nM, respectively. Moreover, the synthesized TCSs were simulated using force field methods whereas the binding energies of the selected compounds were estimated using MM-GBSA method. The findings indicate the present novel 3-ethoxy salicylaldehyde-based thiosemicarbazones to be excellent hits for pharmaceutical applications.

Docking Related Survey on Heterocyclic Compounds Based on Glucosamine-6- Phosphate Synthase Inhibitors and their Antimicrobial Potential

The synthetic heterocyclic compounds have their importance due to their wide applications in various fields of science. The heterocyclic compounds have been reported for their anticancer, antitubercular, insecticides, analeptics, analgesic, anti-bacterial, anti-viral, anti-fungal, and weedicidal activity. Researchers have tried various newer targets in search of better antimicrobials acting via novel mechanisms. Glucosamine-6-Phosphate synthase is an enzyme present in microbial cells. The inactivation of G-6-P synthase may serve as a novel approach to find better antimicrobials. The increasing demands development of newer and effective antimicrobial drugs has reported in search of newer techniques for the generation of new drugs. Hence, the molecular docking technique shall be explored to find or investigate the newer target finding the novel compounds which can be an active antimicrobial compound. The present review has focused on the reported heterocyclic compounds which have been evaluated for their antimicrobial potential using G-6-P synthase as a target. The results of in silico methods and in vitro methods have been compared and critically discussed.

Thiosemicarbazone derivatives: Design, synthesis and in vitro antimalarial activity studies

Different types of thiosemicarbazone derivatives were designed and tested for their Drug-Like Molecular (DLM) nature by using Lipinski and Veber rules. Subsequently, compounds with DLM properties were synthesized and characterized by spectral methods. In vitro antimalarial activity studies of the synthesized thiosemicarbazone derivatives have been carried out against Plasmodium falciparum, 3D7 strain using fluorescence assay method and found that the compounds, (E)-2-(1-(4-fluorophenyl)ethylidene)hydrazine-1-carbothioamide (6), (E)-2-(1-(3-bromophenyl) ethylidene) hydrazine-1-carbothioamide (15) and (E)-2-(3,4,5-trimethoxybenzylidene) hydrazine-1-carbothioamide (29) showed notable antimalarial activity with EC₅₀ values of 13.54 μM, 15.83 μM and 14.52 μM respectively.

Anti-methanogenic effect of rhubarb (Rheum spp.) - An in silico docking studies on methyl-coenzyme M reductase (MCR)

The present study explored anti-methanogenic properties of rhubarb compounds using in silico analysis on methyl-coenzyme M reductase (MCR) for identifying its anti-methanogen mechanism. To identify pharmacokinetics of 35 compounds from rhubarb, molecular docking and ADME analysis were performed against MCR using AutoDockVina, FAFDrugs3 and PROTOX programs. Docking results successfully indicated three possible candidate compounds 9,10-anthracenedione, 1,8-dihydroxy-3-methyl (−6.92 kcal/mol); phthalic acid isobutyl octadecyl ester (−5.26 kcal/mol); and diisooctyl phthalate (−5.61 kcal/mol) showed minimum binding energy (kcal/mol) with the target protein MCR which catalyze the biosynthesis of rumen methane. In conclusion, the identified compounds showed the most docking fitness score against the target methyl-coenzyme M reductase and the decrease in ruminal methane emission by rhubarb might be a result of these compounds by inhibition of methanogenesis.

Studies on Isoniazid Derivatives through a Medicinal Chemistry Approach for the Identification of New Inhibitors of Urease and Inflammatory Markers

A library of thiosemicarbazide derivatives of isoniazid 3-27, was synthesized and evaluated for their anti-inflammatory and urease inhibition activities, by using in vitro bioassays. Among these compounds 9, 10, 12, 21, and 26 were identified as new derivatives. Prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs) and infections caused by Helicobacter pylori (ureolytic bacteria), are the two most significant causes of gastric and peptic ulcers. We focused on the identification of the dual inhibitors of inflammation and urease enzyme. Compound 23 was identified as the best dual inhibitor of inflammation (ROS; IC50 = 12.3 µg/mL), and urease enzyme inhibition activity (IC50 = 22.4 µM). Many of these compounds showed comparable activities to the standard anti-inflammatory drug (ibuprofen, IC50 = 11.2 µg/mL) and urease inhibitor (thiourea/acetohydraoxamic acid, IC50 = 21.1/20.3 µM). Compound 12 was found to be the most potent urease inhibitor (IC50 = 12.3 µM) and good inhibitor of inflammation (IC50 = 27.7 µg/mL). Compounds 19, 11, 13, 9, 17, 10, and 16, were also found to be potent inhibitors of urease. Cytotoxicity was also evaluated and all the compounds were found to be non-cytotoxic, except compound 18 and the parent drug isoniazid (IC50 = 29.5 and 28.5 µM, respectively).

Design, synthesis and in silico study of pyridine based 1,3,4-oxadiazole embedded hydrazinecarbothioamide derivatives as potent anti-tubercular agent

Development of novel, safe and effective drug candidates combating the emerging drug resistance has remained a major focus in the mainstream of anti-tuberculosis research. Here, we inspired to design and synthesize series of new pyridin-4-yl-1,3,4-oxadiazol-2-yl-thio-ethylidene-hydrazinecarbothioamide derivatives as potential anti-tubercular agents. The anti-tubercular bioactive assay demonstrated that the synthesized compounds exhibit potent anti-tubercular activity (MIC = 3.9-7.81 μg/mL) in comparison with reference drugs Rifampicin and Isoniazid.We employed pharmacophore probing approach for the identification of CYP51 as a possible drug target for the synthesized compounds. To understand the preferable binding mode, the synthesized molecules were docked onto the active site of Sterol 14 α-demethylases (CYP51) target. From the binding free energy of the docking results it was revealed that the compounds were effective CYP51 inhibitors and acts as antitubercular agent.

Peel bond strength and antifungal activity of two soft denture lining materials incorporated with 1% chlorhexidine diacetate

Two soft denture lining materials (SC-Soft Confort and TS-Trusoft) were investigated with and without the addition of 1.0% of chlorhexidine diacetate (1.0% CHX). To assess peel bond strength, specimens (75×10×6 mm) were submitted to a peel test at 10 mm/min immediately and after 24 h. To evaluate Candida albicans growth inhibition, disc of specimens (10×3 mm) were immersed in a solution with 3×10⁶ CFU/mL of C. albicans, and spectral measurements were made following immersion in MTT solution for 2, 4, and 6 days. The agar diffusion test was performed by investigating the diameters of inhibition zones around the disc of specimens (10×3 mm)after 48 h. Data were submitted to statistical analysis (α=0.05) and the failure modes were visually classified. The incorporation of 1.0% CHX significantly decreased the peel bond strength for TS (p=0.001) and SC (p=0.005) for immediate test and for TS after 24 h (p=0.010), but not for SC. C. albicans growth was decreased for both materials over time (p<0.05). SC presented inhibition zones approximately 2.0 times larger than TS. The incorporation of 1.0% CHX inhibited fungal growth without impairment to the peel bond strength for SC after 24 h.

Biological evaluation and molecular modelling study of thiosemicarbazide derivatives as bacterial type IIA topoisomerases inhibitors

In the present article, we describe the inhibitory potency of nine thiosemicarbazide derivatives against bacterial type IIA topoisomerases, their antibacterial profile and molecular modelling evaluation. We found that one of the tested compounds, compound 7, significantly inhibits activity of Staphylococcus aureus DNA gyrase with an IC(50) below 15 μM. Besides, this compound displays antibacterial activity on reference Staphylococuss spp. and Enterococcus faecalis strains as well as clinical S. aureus isolates at non-cytotoxic concentrations in mammalian cells with MIC values ranging from 16 to 32 μg/mL thereby indicating, in some cases, equipotent or even more effective action than standard drugs such as vancomycin, ampicillin and nitrofurantoin. The computational studies showed that both molecular geometry and the electron density distribution have a great impact on antibacterial activity of thiosemicarbazide derivatives.

Structure of N-myristoyltransferase from Aspergillus fumigatus

N-Myristoyltransferase (NMT) is an enzyme which translocates the 14-carbon saturated fatty acid myristate from myristoyl-CoA to the N-terminal glycine of substrate peptides. This myristoylation process is involved in protein modification in various eukaryotes, including animals and fungi. Furthermore, this enzyme has been shown to be essential to the growth of various species, such as Saccharomyces cerevisiae, which indicates that NMT is an attractive target for the development of a novel antifungal drug. In this study, the crystal structure of a ternary complex of NMT from Aspergillus fumigatus with S-(2-oxo)pentadecyl-CoA, a myristoyl-CoA analogue cofactor, and a synthetic inhibitor is reported at a resolution of 2.1 Å. The results advance the understanding of the specificity of NMT inhibitors and provide valuable information for structure-based drug design.

1,4-Disubstituted thiosemicarbazide derivatives are potent inhibitors of Toxoplasma gondii proliferation

A series of 4-arylthiosemicarbazides substituted at the N1 position with a 5-membered heteroaryl ring was synthesized and evaluated in vitro for T. gondii inhibition proliferation and host cell cytotoxicity. At non-toxic concentrations for the host cells all studied compounds displayed excellent anti-parasitic effects when compared to sulfadiazine, indicating a high selectivity of their anti-T. gondii activity. The differences in bioactivity investigated by DFT calculations suggest that the inhibitory activity of 4-aryl-thiosemicarbazides towards T. gondii proliferation is connected with the electronic structure of the molecule. Further, these compounds were tested as potential antibacterial agents. No growth-inhibiting effect on any of the test microorganisms was observed for all the compounds, even at high concentrations.

Etodolac Thiosemicarbazides: A novel class of hepatitis C virus NS5B polymerase inhibitors

A novel series of new etodolac hydrazide derivatives, 1-[2-(1,8-diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-yl)acetyl]-4-alkyl/aryl thiosemicarbazides [3a-h] have been synthesized in this study. The structures of the new compounds were determined by spectral (FT-IR, ¹H-NMR, ¹³C-NMR and LC-MS) methods. Inhibition of hepatitis C virus NS5B RNA dependent RNA polymerase activity by etodolac thiosemicarbazides was evaluated in vitro by primer dependent elongation assays. The most active compounds of this series were 3a (SGK 224), 3d (SGK 227) and 3e (SGK 229) with IC50 values of 18.7 μM, 29.2 μM and 16.8 μM, respectively. Binding mode investigations of the most active compound 1-[2-(1,8-diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-yl)acetyl]-4-allyl thiosemicarbazide (3e) suggested that TP-II of HCV NS5B polymerase may be the potential binding site for etodolac thiosemicarbazides and provided clues for modifications to improve the potency of etodolac derivatives.