Agata Paneth

Search for factors affecting antibacterial activity and toxicity of 1,2,4-triazole-ciprofloxacin hybrids.

A series of 1,2,4-triazole-based compounds was designed as potential antibacterial agents using molecular hybridization approach. The target compounds (23-44) were synthesized by Mannich reaction of 1,2,4-triazole-3-thione derivatives with ciprofloxacin (CPX) and formaldehyde. Their potent antibacterial effect on Gram-positive bacteria was accompanied by similarly strong activity against Gram-negative strains. The toxicity of the CPX-triazole hybrids for bacterial cells was even up to 18930 times higher than the toxicity for human cells. The results of enzymatic studies showed that the antibacterial activity of the CPX-triazole hybrids is not dependent solely on the degree of their affinity to DNA gyrase and topoisomerase IV.

Determination of the Primary Molecular Target of 1,2,4-Triazole-Ciprofloxacin Hybrids

We have synthesized and examined the antibacterial activity, toxicity and affinity towards bacterial type II topoisomerases of a series of 1,2,4-triazole-ciprofloxacin hybrids. A number of these compounds displayed enhanced activity against Gram-positive and Gram-negative bacteria when compared to ciprofloxacin. The toxic concentrations of the obtained derivatives, evaluated on HEK-293 cells using MTT assay, were much higher than concentrations required to produce antibacterial effect. Finally, the results of enzymatic studies showed that the analyzed compounds demonstrated other preferences as regards primary and secondary molecular targets than ciprofloxacin.

Synthesis and In Vitro Antiproliferative Activity of Thiazole-Based Nitrogen Mustards: The Hydrogen Bonding Interaction between Model Systems and Nucleobases

Synthesis, characterization and investigation of antiproliferative activity of eight thiazole-based nitrogen mustard against human cancer cells lines (MV4-11, A549, HCT116 and MCF-7) and normal mouse fibroblast (BALB/3T3) are presented. Their structures were determined using NMR, FAB MS, HRMS and elemental analyses. Among the derivatives, 3a, 3b, 3e and 3h were found to exhibit high activity against human leukemia MV4-11 cells with IC50 values of 0.634-3.61 µg/ml. The cytotoxic activity of compound 3a against BALB/3T3 cells is up to 40 times lower than against cancer cell lines. Our data indicated also that compound 3e had very strong activity against MCF-7 and HCT116 with IC50 equal to 2.32 µg/ml and 2.81 µg/ml, respectively. Their activity was similar to the activity of cis-platin, which is clinically used as anticancer drug in the treatment of human solid tumours. We also perform quantum chemical calculation of interaction and binding energies in complexes of model systems and 3e with DNA bases. Interaction of real drug 3e with guanine is much stronger than with the remaining nucleobases, and the strongest among all investigated complexes. Computer simulations were performed with ATP-binding domain and DNA-binding site of hTopoII. Compounds 3a-h were recognized as potential inhibitors of hTopoII.

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.

Studies on the Anticonvulsant Activity and Influence on GABA-ergic Neurotransmission of 1,2,4-Triazole-3-thione- Based Compounds

The anticonvulsant activity of several 1,2,4-triazole-3-thione derivatives on mouse maximal electroshock-induced seizures was tested in this study. Characteristic features of all active compounds were rapid onset of action and long lasting effect. Structure-activity observations showed that the probability of obtaining compounds exerting anticonvulsant activity was much higher when at least one of the phenyl rings attached to 1,2,4-triazole nucleus had a substituent at the para position. The obtained results, moreover, permit us to conclude that despite the structural similarity of loreclezole (second-generation anticonvulsant drug) and the titled compounds, their anticonvulsant activity is achieved via completely different molecular mechanisms.

Searching for novel scaffold of triazole non-nucleoside inhibitors of HIV-1 reverse transcriptase

Abstract Azoles are a promising class of the new generation of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). From thousands of reported compounds, many possess the same basic structure of an aryl substituted azole ring linked by a thioglycolamide chain with another aromatic ring. In order to find novel extensions for this basic scaffold, we explored the 5-position substitution pattern of triazole NNRTIs using molecular docking followed by the synthesis of selected compounds. We found that heterocyclic substituents in the 5-position of the triazole ring are detrimental to the inhibitory activity of compounds with four-membered thioglycolamide linker and this substitution seems to be viable only for compounds with shorter two-membered linker. Promising compound, N-(4-carboxy-2-chlorophenyl)-2-((4-benzyl-5-methyl-4H-1,2,4-triazol-3-yl)sulfanyl)acetamide, with potent inhibitory activity and acceptable aqueous solubility has been identified in this study that could serve as lead scaffold for the development of novel water-soluble salts of triazole NNRTIs.

Structure–activity Relationship Studies of Microbiologically Active Thiosemicarbazides Derived from Hydroxybenzoic Acid Hydrazides

Forty‐five derivatives of thiosemicarbazide were synthesized, and their antibacterial activity against Gram‐positive and Gram‐negative bacteria was evaluated. Some of the described compounds exhibited interesting activity against reference strains of Gram‐positive bacteria, whereas only two derivatives had the ability to inhibit the growth of Gram‐negative species (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, Proteus mirabilis ATCC 12453). The most potent antimicrobial activity was observed in the cases of salicylic acid hydrazide derivatives. The differences in activity inspired us to conduct conformational analysis using molecular mechanics level. The obtained results suggest that the molecule geometry, especially at the N4–terminus of thiosemicarbazide skeleton, determines the antibacterial activity. Unfortunately, in opposition to what we expected, only one of the tested compounds inhibited the activity of the topoIV enzyme, and none of them was active against DNA gyrase.

Triazole-Based Compound as a Candidate To Develop Novel Medicines To Treat Toxoplasmosis

ABSTRACT This article reports anti-Toxoplasma gondii activity of 3-(thiophen-2-yl)-1,2,4-triazole-5-thione. The compound displayed significant and reproducible antiparasitic effects at nontoxic concentrations for the host cells, with an experimentally determined 50% inhibitory concentration (IC50) at least 30 times better than that of the known chemotherapeutic agent sulfadiazine. Purine nucleoside phosphorylase was defined as the probable target for anti-Toxoplasma activity of the tested compound. These results provide the foundation for future work to develop a new class of medicines to better treat toxoplasmosis.

Synthesis and in vitro antiproliferative and antibacterial activity of new thiazolidine-2,4-dione derivatives

Abstract In our present research, we synthesised new thiazolidine-2,4-diones (12–28). All the newly synthesised compounds were evaluated for antiproliferative and antibacterial activity. Antiproliferative evaluation was carried out using normal human skin fibroblasts and tumour cell lines: A549, HepG2, and MCF-7. The IC50 values were determined for tested compounds revealing antiproliferative activity. Moreover, safety index (SI) was calculated. Among all tested derivatives, the compound 18 revealed the highest antiproliferative activity against human lung, breast, and liver cancer cells. More importantly, the derivative 18 showed meaningfully lower IC50 values when compared to the reference substance, irinotecan, and relatively high SI values. Moreover, newly synthesised compounds were screened for the bacteria growth inhibition in vitro. According to our screening results, most active compound was the derivative 18 against Gram-positive bacteria. Therefore, it may be implied that the novel compound 18 appears to be a very promising agent for anticancer treatment. Graphical Abstract

Pharmacological and Structure-Activity Relationship Evaluation of 4-aryl-1-Diphenylacetyl(thio)semicarbazides

This article describes the synthesis of six 4-aryl-(thio)semicarbazides (series a and b) linked with diphenylacetyl moiety along with their pharmacological evaluation on the central nervous system in mice and computational studies, including conformational analysis and electrostatic properties. All thiosemicarbazides (series b) were found to exhibit strong antinociceptive activity in the behavioural model. Among them, compound 1-diphenylacetyl-4-(4-methylphenyl)thiosemicarbazide 1b was found to be the most potent analgesic agent, whose activity is connected with the opioid system. For compounds from series a significant anti-serotonergic effect, especially for compound 1-diphenylacetyl-4-(4-methoxyphenyl)semicarbazide 2b was observed. The computational studies strongly support the obtained results.