Synthesis, anticonvulsant activity, and molecular modeling studies of novel 1-phenyl/1-(4-chlorophenyl)-2-(1H-triazol-1-yl)ethanol ester derivatives

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

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.

Antibacterial azole derivatives: Antibacterial activity, cytotoxicity, and in silico mechanistic studies

Azole antifungal drugs are commonly used in antifungal chemotherapy. Antibacterial effects of some topical antifungals, such as miconazole and econazole, have lately been revealed, which suggests a promising venue in antimicrobial chemotherapy. In this study, we tested an in-house azole collection with antifungal properties for their antibacterial activity to identify dual-acting hits using the broth microdilution method. The in vitro screen yielded a number of potent derivatives against gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus. Compound 73's minimum inhibitory concentration (MIC) value less than 1 μg/ml against S. aureus; however, none of the compounds showed noteworthy activity against methicillin-resistant S. aureus (MRSA). All the active compounds were found safe at their MIC values against the healthy fibroblast cells in the in vitro cytotoxicity test. Molecular docking studies of the most active compounds using a set of docking programs with flavohemoglobin (flavoHb) structure, the proposed target of the azole antifungals with antibacterial activity, presented striking similarities regarding the binding modes and interactions between the tested compounds and the antifungal drugs with crystallographic data. In addition to being noncytotoxic, the library was predicted to be drug-like and free of pan-assay interference compounds (PAINS). As a result, the current study revealed several potential azole derivatives with both antifungal and antibacterial activities. Inhibition of bacterial flavoHb was suggested as a possible mechanism of action for the title compounds.

Antifungal screening and in silico mechanistic studies of an in-house azole library

Systemic Candida infections pose a serious public health problem with high morbidity and mortality. C. albicans is the major pathogen identified in candidiasis; however, non-albicans Candida spp. with antifungal resistance are now more prevalent. Azoles are first-choice antifungal drugs for candidiasis; however, they are ineffective for certain infections caused by the resistant strains. Azoles block ergosterol synthesis by inhibiting fungal CYP51, which leads to disruption of fungal membrane permeability. In this study, we screened for antifungal activity of an in-house azole library of 65 compounds to identify hit matter followed by a molecular modeling study for their CYP51 inhibition mechanism. Antifungal susceptibility tests against standard Candida spp. including C. albicans revealed derivatives 12 and 13 as highly active. Furthermore, they showed potent antibiofilm activity as well as neglectable cytotoxicity in a mouse fibroblast assay. According to molecular docking studies, 12 and 13 have the necessary binding characteristics for effective inhibition of CYP51. Finally, molecular dynamics simulations of the C. albicans CYP51 (CACYP51) homology model's catalytic site complexed with 13 were stable demonstrating excellent binding.