Synthesis of Benzimidazole-1,2,4-triazole Derivatives as Potential Antifungal Agents Targeting 14α-Demethylase

Abstract

Invasive fungal infections (IFIs) are increasing as major infectious diseases around the world, and the limited efficacy of existing medications has resulted in substantial morbidity and death in patients due to the lack of effective antifungal agents and serious drug resistance. In this study, a series of benzimidazole-1,2,4-triazole derivatives (6a−6l) were synthesized and characterized by 1 H NMR, 13 C NMR, and HR-MS spectral analysis. All the target compounds were screened for their in vitro antifungal activity against four fungal strains, namely, C. albicans, C. glabrata, C. krusei, and C. parapsilopsis. The synthesized compounds exhibited significant antifungal potential, especially against C. glabrata. Three compounds (6b, 6i, and 6j) showed higher antifungal activity with their MIC values (0.97 μg/mL) compared with voriconazole and fluconazole. Molecular docking provided a possible binding mode of compounds 6b, 6i, and 6j in the 14α-demethylase active site. Our studies suggested that the benzimidazole-1,2,4-triazole derivatives can be used as a new fungicidal lead targeting 14α-demethylase for further structural optimization. In addition, their effects on the L929 cell line were also investigated to evaluate the cytotoxic effects of the compounds. SEM analyses were performed to examine the effects of compounds 6a, 6i, and 6j on C. glabrata cells under in vivo experimental conditions.

Exploration of Remarkably Potential Multitarget-Directed N-Alkylated-2-(substituted phenyl)-1H-benzimidazole Derivatives as Antiproliferative, Antifungal, and Antibacterial Agents

“…However, the replacement of the methoxy group and a hydrogen atom on the phenyl moiety with trifluoromethyl and the presence of a longer alkyl chain having carbon atoms from two to seven (compounds 3b – g ) resulted in a loss of action against the two tested strains with MIC values of more than 1024 μg mL –1 , which is similar to the previous report of Khabnadideh et al These findings suggested that the character of the substituents simultaneously determines antifungal activities at the second position and the length of the carbon atoms in the alkyl chain at the first position. In accordance with a previous review, a plausible antifungal mode of action for the synthesized compounds is illustrated in Figure by inhibition of the ergosterol synthesis causing fungal cell membrane degradation. , After crossing the cell membrane, these molecules have previously been reported to be able to inhibit the cytochrome P450 enzyme lanosterol 14α-demethylase (CYP51), ,− a crucial enzyme that plays an essential role in sterol biosynthesis, especially ergosterol . These molecules reduce the function of 14α-demethylase by interacting with heme iron in the active site and then inducing the enzyme to alter its active site geometry and block the demethylation of lanosterol to ergosterol, one of the fungal membrane’s structural components regulating membrane fluidity and permeability. ,, When ergosterol production is inhibited, the fungal cell wall destabilizes and swiftly disrupts, resulting in the death of the fungus. , …”

“…In accordance with a previous review, a plausible antifungal mode of action for the synthesized compounds is illustrated in Figure 4 by inhibition of the ergosterol synthesis causing fungal cell membrane degradation. 40 , 41 After crossing the cell membrane, these molecules have previously been reported to be able to inhibit the cytochrome P450 enzyme lanosterol 14α-demethylase (CYP51), 19 , 42 − 44 a crucial enzyme that plays an essential role in sterol biosynthesis, especially ergosterol. 45 These molecules reduce the function of 14α-demethylase by interacting with heme iron in the active site and then inducing the enzyme to alter its active site geometry and block the demethylation of lanosterol to ergosterol, one of the fungal membrane’s structural components regulating membrane fluidity and permeability.…”

Synthesis, DFT Calculations, In Silico Studies, and Antimicrobial Evaluation of Benzimidazole-Thiadiazole Derivatives

“…krusei (ATCC 6258), and C. parapsilosis (ATCC 22 019)) according to the microdilution standard methods CLSI M07-A9 (2012) and NCCLS M27-A2 (2002), as described in the previous study. , …”

“…The antimicrobial activity of the final compounds ( 5a – i ) was screened against eight species of pathogenic bacteria and three fungal species ( E. coli (ATCC 25922), S. marcescens (ATCC 8100), K. pneumonia (ATCC 13883), P. aeruginosa (ATCC 27853), E. faecalis (ATCC 2942), B. subtilis (NRRL NRS 744), S. aureus (ATCC 29213), S. epidermidis (ATCC 12228), C. albicans (ATCC 24433), C. glabrata (ATCC 90030), C. krusei (ATCC 6258), and C. parapsilosis (ATCC 22 019)) according to the microdilution standard methods CLSI M07-A9 (2012) and NCCLS M27-A2 (2002), as described in the previous study. 25 , 26 …”

“…4 standard methods CLSI M07-A9 (2012) and NCCLS M27-A2 (2002), as described in the previous study. 25,26 4.3. Cytotoxicity Assay.…”