Discovery of 1,2,3-selenadiazole analogues as antifungal agents using a scaffold hopping approach

Selenization of Small Molecule Drugs: A New Player on the Board

There is an urgent need to develop safer and more effective modalities for the treatment of a wide range of pathologies due to the increasing rates of drug resistance, undesired side effects, poor clinical outcomes, etc. Throughout the years, selenium (Se) has attracted a great deal of attention due to its important role in human health. Besides, a growing body of work has unveiled that the inclusion of Se motifs into a great number of molecules is a promising strategy for obtaining novel therapeutic agents. In the current Perspective, we have gathered the most recent literature related to the incorporation of different Se moieties into the scaffolds of a wide range of known drugs and their feasible pharmaceutical applications. In addition, we highlight different representative examples as well as provide our perspective on Se drugs and the possible future directions, promises, opportunities, and challenges of this ground-breaking area of research.

Developing Novel Coumarin-Containing Azoles Antifungal Agents by the Scaffold Merging Strategy for Treating Azole-Resistant Candidiasis

The extensive use of antifungal drugs has resulted in severe drug resistance, making clinical treatment of fungal infections more difficult. Biofilm inhibitors can overcome drug resistance by inhibiting fungal biofilm formation. In this study, some coumarins with antibiofilm activity were merged into CYP51 inhibitors to produce novel molecules possessing potent antiresistance activity. As expected, most compounds exhibited excellent in vitro antifungal activity against pathogenic fungi, especially fluconazole-resistant candidiasis. Then, their mechanism was confirmed by sterol composition analysis and morphological observation. Biofilm inhibition and down-regulation of resistance-related genes were employed to confirm the compounds' antiresistance mechanisms. Significantly, compound A32 demonstrated fungicidal activity against fluconazole-resistant strain 904. Most importantly, compound A32 showed potent in vivo antifungal activity against pathogenic fungi and fluconazole-resistant strains. Preliminary pharmacokinetic and toxicity tests demonstrated that the compounds possessed favorable druggability. Taken together, compound A32 represents a promising lead to develop novel antifungal agents for treating azole-resistant candidiasis.

Synthesis, Characterization, and Antimicrobial Activity of New 1,2,3-Thiadiazole and 1,2,3-Selenadiazole Derivatives

1,2,3-Thiadiazole, 1,2,3-selenadiazole, and semicarbazones that are prepared from ketones are promising moieties for lead compound development. New 1,2,3-thiadiazole (2c-4c) and 1,2,3-selenadiazole derivatives (2d–4d) were prepared from the corresponding semicarbazones (2b-4b). The semicarbazones (2b-4b) were prepared from the corresponding ketones (2a-4a). Characterization of the synthesized compounds was performed using infrared spectra (IR), proton nuclear magnetic resonance (1H-NMR) spectra, carbon nuclear magnetic resonance (13C-NMR), ultraviolet spectra, mass spectrometry, and elemental analysis. The antimicrobial activity of the prepared compounds was explored in vitro against various pathogenic microbes. All heterocyclic compounds had positive antimicrobial activity, but these activities varied in the extent of antimicrobial coverage. Compounds (2c) and (2d) had positive activity against Staphylococcus aureus and Escherichia coli but without any antipseudomonal activity. Compound (3c) had the most activity against Candida albicans with potential as a novel antifungal agent along with activity against some Gram-positive and Gram-negative bacteria. Compounds (4c) and (4d) exhibited broad-spectrum coverage in which both compounds demonstrated antimicrobial activity against all microorganisms explored. Interestingly, they both had substantial antipseudomonal activity against local resistant Pseudomonas aeruginosa and reference P. aeruginosa (ATCC 27853). This may suggest the potential for compounds (4c) and (4d) as novel broad-spectrum antibacterial agents with promising antipseudomonal activity. In conclusion, new 1,2,3-thiadiazole (2c-4c) and 1,2,3-selenadiazole (2d-4d) derivatives were identified as potential lead compounds for novel antibacterial agents.