In vitro antifungal and antibiofilm activities of novel sulfonyl hydrazone derivatives against Candida spp

Inhibition of apoptosis and biofilm formation in Candida auris by click-synthesized triazole-bridged quinoline derivatives

Candida auris, a recent addition to the Candida species, poses a significant threat with its association to numerous hospital outbreaks globally, particularly affecting immunocompromised individuals. Given its resistance to existing antifungal therapies, there is a pressing need for innovative treatments. In this study, novel triazole bridged quinoline derivatives were synthesized and evaluated for their antifungal activity against C. auris. The most promising compound, QT7, demonstrated exceptional efficacy with a minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 0.12 μg mL-1 and 0.24 μg mL-1, respectively. Additionally, QT7 effectively disrupted mature biofilms, inhibiting them by 81.98% ± 8.51 and 89.57 ± 5.47 at MFC and 2× MFC values, respectively. Furthermore, QT7 induced cellular apoptosis in a dose-dependent manner, supported by various apoptotic markers such as phosphatidylserine externalization, mitochondrial depolarization, and reduced cytochrome c and oxidase activity. Importantly, QT7 exhibited low hemolytic activity, highlighting its potential for further investigation. Additionally, the physicochemical properties of this compound suggest its potential as a lead drug candidate, warranting further exploration in drug discovery efforts against Candida auris infections.

Artemisinin May Disrupt Hyphae Formation by Suppressing Biofilm-Related Genes of Candida albicans: In Vitro and In Silico Approaches

This study aimed to assess the antifungal and antibiofilm efficacy of artemisinin against Candida (C.) species, analyze its impact on gene expression levels within C. albicans biofilms, and investigate the molecular interactions through molecular docking. The antifungal efficacy of artemisinin on a variety of Candida species, including fluconazole-resistant and -susceptible species, was evaluated by the microdilution method. The effect of artemisinin on C. albicans biofilm formation was investigated by MTT and FESEM. The mRNA expression of the genes related to biofilm was analyzed by qRT-PCR. In addition, molecular docking analysis was used to understand the interaction between artemisinin and C. albicans at the molecular level with RAS1-cAMP-EFG1 and EFG1-regulated genes. Artemisinin showed higher sensitivity against non-albicans Candida strains. Furthermore, artemisinin was strongly inhibitory against C. albicans biofilms at 640 µg/mL. Artemisinin downregulated adhesion-related genes ALS3, HWP1, and ECE1, hyphal development genes UME6 and HGC1, and hyphal CAMP-dependent protein kinase regulators CYR1, RAS1, and EFG1. Furthermore, molecular docking analysis revealed that artemisinin and EFG1 had the highest affinity, followed by UME6. FESEM analysis showed that the fluconazole- and artemisinin-treated groups exhibited a reduced hyphal network, unusual surface bulges, and the formation of pores on the cell surfaces. Our study suggests that artemisinin may have antifungal potential and showed a remarkable antibiofilm activity by significantly suppressing adhesion and hyphal development through interaction with key proteins involved in biofilm formation, such as EFG1.

Small Schiff Base Molecules-A Possible Strategy to Combat Biofilm-Related Infections

Microorganisms participating in the development of biofilms exhibit heightened resistance to antibiotic treatment, therefore infections involving biofilms have become a problem in recent years as they are more difficult to treat. Consequently, research efforts are directed towards identifying novel molecules that not only possess antimicrobial properties but also demonstrate efficacy against biofilms. While numerous investigations have focused on antimicrobial capabilities of Schiff bases, their potential as antibiofilm agents remains largely unexplored. Thus, the objective of this article is to present a comprehensive overview of the existing scientific literature pertaining to small molecules categorized as Schiff bases with antibiofilm properties. The survey involved querying four databases (Web of Science, ScienceDirect, Scopus and Reaxys). Relevant articles published in the last 10 years were selected and categorized based on the molecular structure into two groups: classical Schiff bases and oximes and hydrazones. Despite the majority of studies indicating a moderate antibiofilm potential of Schiff bases, certain compounds exhibited a noteworthy effect, underscoring the significance of considering this type of molecular modeling when seeking to develop new molecules with antibiofilm effects.

Synthesis and in Silico Studies of Some New 1,2,3-Triazolyltetrazole Bearing Indazole Derivatives as Potent Antimicrobial Agents

1,2,3-Triazole and tetrazole derivatives bearing pyrrolidines are found to exhibit notable biological activity and have become useful scaffolds in medicinal chemistry for application in lead discovery and optimization. Novel indazole bearing 1,2,3-triazolyltetrazoles were designed as potential antimicrobial candidates. The structure of duel heterocyclics was validated by a spectroscopic technique of infrared (IR), nuclear magnetic resonance (1 H and 13 C NMR), and mass spectral data. Compounds 4b, 4c, 4d, and 4h were found to have a stronger antibacterial effect against Gram-positive (S. aureus, B. subtilis, M. Luteus) and Gram-negative (E. coli, P. aeruginosa) microorganisms with MICs ranging from 5±0.03-18±0.02 μM, respectively. Moreover, scaffolds 4a, 4h showed potent antifungal activity against A. flavus, M. gypsuem strains with MIC values of 10±0.02, 11±0.01 μM, which are similar activity that of the standard Itraconazole (MIC=8±0.02, 10±0.01 μM). The binding mode for compound 4 inside the catalytic pocket of S. aureus complexed with nicotinamide adenine dinucleotide phosphate and trimethoprim and produced a network of hydrophobic and hydrophilic interactions (3FRE). From in silico results, 4b demonstrated highly stable hydrogen binding amino acids Leu62(X) [N18…O, 2.47 Å], Arg44(X) [N17…N, 3.11 Å], Thr96(X) [N10…OG1, 3.05 Å], Gly94(X) [F7…N, 2.82 Å], and Gly43(X) [F7…N, 2.90 Å], which are plays a crucial role in ensuring efficient binding of the ligand in a crystal structure of antibacterial receptor. Furthermore, the physicochemical and ADME filtration molecular properties, estimation of toxicity, and bioactivity scores of these novel scaffolds were evaluated by using SwissADME and ADMETlab2.0 online protocols. Thus, the significant antimicrobial activity of indazole linked to duel heterocyclic compounds can be used for development of new antimicrobial agents with further modifications.

Synthesis of Imidazole-2,3-dihydrothiazole Compounds as VEGFR-2 Inhibitors and Their Support with in Silico Studies

In this study, 12 novel 2-((1-(4-(1H-imidazol-1-yl)phenyl)ethylidene)hydrazineylidene)-3-ethyl-4-(substitutephenyl)-2,3-dihydrothiazole derivatives were obtained. Among these compounds, 2-((1-(4-(1H-imidazol-1-yl)phenyl)ethylidene)hydrazineylidene)-4-([1,1'-biphenyl]-4-yl)-3-ethyl-2,3-dihydrothiazole (4h) was chosen as the most active derivative in the series. According to the MTT results, compounds 4h and 4k showed activity with IC50 =4.566±0.246 μM and IC50 =4.537±0.463 μM, respectively. Unlike other derivatives, compound 4h carries a phenyl ring in the 4th position of the phenyl ring. This bulky group allowed the compound to settle in the enzyme active site. Dynamic studies show that the stability of the compound does not change over 40 ns. RMSD, RMSF and Rg parameters all remained within acceptable limits. The uninterrupted aromatic hydrogen bonding of the enzyme active site with the important amino acids Cys919, Glu885 and Asp1046 proves the inhibitory potential of compound 4h on the VEGFR-2 enzyme. It is thought that more active compounds will be reached with the derivatives to be synthesized starting from compound 4h.

Synthesis, Antifungal Activities, Molecular Docking and Molecular Dynamic Studies of Novel Quinoxaline-Triazole Compounds

Uncontrolled use of antifungal drugs affects the development of resistance to existing drugs. Azole antifungals constitute a large part of antifungal therapy. Therefore, there is a need for new azole antifungals. Within the scope of this study, 17 new triazole derivative compounds were synthesized. Structure determinations were clarified by spectroscopic analysis methods (¹H-NMR, ¹³C-NMR, HRMS). In addition, structure matching was completed using two-dimensional NMR techniques, HSQC, HMBC and NOESY. The antifungal effects of the compounds were evaluated on Candida strains by means of in vitro method. Compound 5d showed activity against Candida glabrata with a MIC₉₀ = 2 μg/mL. Compound 5d showed activity against Candida krusei with a MIC₉₀ = 2 μg/mL. This activity value, which is higher than fluconazole, is promising. In addition, the biofilm inhibition percentages of the compounds were calculated. Molecular docking and molecular dynamics simulations performed with compound 5d are in harmony with activity studies.