Journal of Mazandaran University of Medical Sciences (Jun 2024)
Synthesis and Antifungal Activity Evaluation of a Fluconazole Analog Derived from Dithiocarbamate
Abstract
Background and purpose: Among the different categories of antifungal drugs, azole antifungals have received more attention due to their broad spectrum, high potency, and acting on specific target enzyme. Fluconazole is one of these drugs that as a bis-triazole, was the first triazole drug to enter the market. New-generation antifungal drugs such as albaconazole and voriconazole have been designed by replacing one of the triazole rings of fluconazole with other heterocycles. Based on this strategy, in this research, a new derivative of fluconazole in which a triazole residue of fluconazole is replaced by 4-benzylpiperazine dithiocarbamate was synthesized and its effects were evaluated in vitro. Materials and methods: The desired final compound (6) was obtained from the reaction of two key intermediates, oxirane, and N-benzylpiperazine, in the presence of carbon disulfide and triethylamine in ethanol. To prepare the oxirane derivative, the reaction of a ketonic compound namely 1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl) ethan-1-one with trimethylsulfoxonium iodide was used. On the other hand, for the synthesis of N-benzyl piperazine, benzyl chloride was refluxed with the excess of piperazine. It should be noted that the purification of the compounds was done with common methods of extraction and recrystallization and there is no need for chromatography. The structure of the final synthesized compound was confirmed by infrared (IR) nuclear magnetic resonance (NMR) and mass spectrometry (MS). The antifungal activity of the synthesized compound was investigated in comparison with fluconazole against several species of pathogenic fungi sensitive to fluconazole, including Candida albicans, Candida glabrata, Candida parapsilosis, Candida krusei, and Candida tropicalis, as well as fluconazole-resistant isolates, and the minimum inhibitory concentration (MIC) was determined in vitro by broth micro-dilution method. In addition, the hemolytic effect on red blood cells and cytotoxicity on HepG2 cells were investigated for this compound. The docking mode of the target compound with lanosterol 14α-demethylase (CYP51) enzyme was also studied. Results: Preliminary investigation of antifungal effects on ten fungi strains sensitive to fluconazole showed that the target compound with MIC values between 0.063 and 1 μg/ml has strong antifungal effects on C. albicans, C. glabrata, C. parapsilosis, C. krusei, and C. tropicalis. In general, its antifungal activity was 4-64 times more than that of fluconazole. Also, the compound showed a good anti-Candida profile against fluconazole-resistant species. While the MIC values of fluconazole against C. albicans and C. krusei isolates were equal to or greater than 64 μg/ml, compound 6 effectively inhibited the growth of C. albicans and C. krusei resistant to fluconazole at concentrations of 8 or 16 μg/ml. The MIC value of this compound against C. parapsilosis was equal to 0.5 μg/ml. The results of in vitro hemolysis and cytotoxicity tests also showed that this compound is as safe for human cells as fluconazole. The docking study showed that the designed compound can interact more tightly with the lanosterol 14α-demethylase enzyme due to the presence of a benzylpiperazine dithiocarbamate scaffold in its structure. Conclusion: According to the obtained results, the compound synthesized in this study is a suitable candidate for conducting in vivo tests and other preclinical and pharmacokinetic tests to discover a new antifungal drug.
