Synthesis and Biological Evaluation of a Series of New Hybrid Amide Derivatives of Triazole and Thiazolidine-2,4-dione.

A series of hybrid compounds with triazole and thiazolidine nuclei connected by a linker has been synthesized and extensively studied. Various synthetic methods for the target compounds have been tested. A microbiological assessment of the obtained compounds was carried out on strains of pathogenic fungi C. albicans, C. non-albicans, multidrug-resistant C. auris, Rhizopus arrhizus, Aspergillus spp. and some dermatophytes and other yeasts. The lowest obtained MIC values for target compounds lie between 0.003 µg/mL and 0.5 µg/mL and therefore the compounds are not inferior or several times better than commercial azole drugs. The length of the acylpiperazine linker has a limited effect on antifungal activity. Some bioisosteric analogues were tested in microbiological analysis, but turned out to be weaker than the leader in activity. The highest activity was demonstrated by a compound with para-chlorobenzylidene substituent in the thiazolidine fragment. Molecular modelling was used to predict binding modes of synthesized molecules and rationalize experimentally observed SAR. The leader compound is twice more effective in inhibiting the formation of germ tubes by Candida albicans yeast cells compared to voriconazole. An increased level of Pdr5, an azoles drug efflux pump was observed, but the increase is lower than that caused by azoles. The results can be useful for further development of more powerful and safe antifungal agents.

Antifungal Thiazolidines: Synthesis and Biological Evaluation of Mycosidine Congeners.

Novel derivatives of Mycosidine (3,5-substituted thiazolidine-2,4-diones) are synthesized by Knoevenagel condensation and reactions of thiazolidines with chloroformates or halo-acetic acid esters. Furthermore, 5-Arylidene-2,4-thiazolidinediones and their 2-thioxo analogs containing halogen and hydroxy groups or di(benzyloxy) substituents in 5-benzylidene moiety are tested for antifungal activity in vitro. Some of the synthesized compounds exhibit high antifungal activity, both fungistatic and fungicidal, and lead to morphological changes in the Candida yeast cell wall. Based on the use of limited proteomic screening and toxicity analysis in mutants, we show that Mycosidine activity is associated with glucose transport. This suggests that this first-in-class antifungal drug has a novel mechanism of action that deserves further study.

Evaluation of New Antimicrobial Agents Based on tris(1H-Indol-3-yl)methylium Salts: Activity, Toxicity, Suppression of Experimental Sepsis in Mice.

The antimicrobial activity and toxicity of three novel synthetic antibacterial agents containing tris(1H-indol-3-yl)methylium fragment were studied in vitro and in vivo. All compounds in vitro revealed high activity (minimal inhibitory concentration (MIC) 0.13-1.0 µg/mL) against bacteria that were either sensitive or resistant to antibiotics, including multidrug-resistant clinical isolates. The derivatives combining high antimicrobial activity with relatively low cytotoxicity against human donor fibroblasts HPF-hTERT were subjected to further testing on mice. In vivo they revealed fairly good tolerance and relatively low toxicity. Acute toxicity was evaluated, and the main indicators of toxicity, including LD50 and LD10, were determined. A study of compounds in vivo showed their efficiency in the model of staphylococcal sepsis in mice. The efficiency of compounds may be due to the ability of indolylmethylium salts to form pores in the cytoplasmic membrane of microbial cells and thereby facilitate the penetration of molecules into the pathogen.

Synthesis and antibacterial activity of novel arylbis(indol-3-yl)methane derivatives.

A series of new compounds-arylbis(indol-3-yl)methylium derivatives-were synthesized and their antimicrobial activity was evaluated. All the compounds turned out to be highly active, with MIC depending on their structure and the length of N-alkyl residues. The parent triarylmethane compounds possess weaker activity.

N-(Hydroxyalkyl) Derivatives of tris(1H-indol-3-yl)methylium Salts as Promising Antibacterial Agents: Synthesis and Biological Evaluation.

The wide spread of pathogens resistance requires the development of new antimicrobial agents capable of overcoming drug resistance. The main objective of the study is to elucidate the effect of substitutions in tris(1H-indol-3-yl)methylium derivatives on their antibacterial activity and toxicity to human cells. A series of new compounds were synthesized and tested. Their antibacterial activity in vitro was performed on 12 bacterial strains, including drug resistant strains, that were clinical isolates or collection strains. The cytotoxic effect of the compounds was determined using an test with HPF-hTERT (human postnatal fibroblasts, immortalized with hTERT) cells. The activity of the obtained compounds depended on the carbon chain length. Derivatives with C5-C6 chains were more active. The minimum inhibitory concentration (MIC) of the most active compound on Gram-positive bacteria, including MRSA, was 0.5 µg/mL. Compounds with C5-C6 chains also revealed high activity against Staphylococcus epidermidis (1.0 and 0.5 µg/mL, respectively) and moderate activity against Gram-negative bacteria Escherichia coli (8 µg/mL) and Klebsiella pneumonia (2 and 8 µg/mL, respectively). However, they have no activity against Salmonella cholerasuis and Pseudomonas aeruginosa. The most active compounds revealed higher antibacterial activity on MRSA than the reference drug levofloxacin, and their ratio between antibacterial and cytotoxic activity exceeded 10 times. The data obtained provide a basis for further study of this promising group of substances.

Synthesis and antimicrobial activity of 3,4-bis(arylthio)maleimides.

A series of 3,4-bis(arylthio)maleimides were synthesized and their antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria, including multidrug resistant (MDR) strains and some fungi. Most compounds turned out to be highly active, activity being dependent on substituents on phenyl rings.