New Ester-Containing Azole Derivatives With Potent Anti-Candida Effects: Synthesis, Antifungal Susceptibility, Cytotoxicity, and Molecular Modeling Studies

Abstract

Mortalities due to mycoses have dramatically increased with the emergence of drug-resistant strains and growing immune-compromised populations globally. Azole antifungals have been the first choice against fungal infections of a wide spectrum and several azole derivatives with ester function were reported for their potentially promising and favorable activity against Candida spp. In this study, we designed and synthesized a series of 1-(aryl)-2-(1H-imidazol-1-yl/1H-1,2,4-triazol-1-yl)ethyl esters, and tested them against seven reference Candida strains using EUCAST reference microdilution method. Among the series, 6a, 6d, and 6g proved highly potent in vitro compared to fluconazole; especially against Candida albicans and Candida tropicalis with minimum inhibitor concentration (MIC) values as low as 0.125 and 0.06 mg/L, respectively, although their activities against Candida krusei and Candida glabrata remained limited. The compounds also showed minimal toxicity to murine fibroblasts according to the in vitro cytotoxicity tests. Molecular modeling predicted 6g as an orally available druglike compound according to all parameters and CYP51 inhibition as the likely mechanism for their antifungal effects. The study underpins the promise of azoles with ester functionality as a potential scaffold for small-molecule antifungal drug design.