Synthesis, Biological Evaluation and Molecular Docking of Certain Sulfones as Potential Nonazole Antifungal Agents

Drug design strategies for the treatment azole-resistant candidiasis

INTRODUCTION

Despite the availability of novel antifungals and therapeutic strategies, the rate of global mortality linked to invasive fungal diseases from fungal infection remains high. Candida albicans account for the most invasive mycosis produced by yeast. Thus, the current arsenal of medicinal chemists is focused on finding new effective agents with lower toxicity and broad-spectrum activity. In this review article, recent efforts to find effective agents against azole-resistant candidiasis, a common fungal infection, are covered.

AREAS COVERED

Herein, the authors outlined all azole-based compounds, dual target, and new scaffolds (non-azole-based compounds) which were effective against azole-resistant candidiasis. In addition, the mechanism of action and SAR studies were also discussed, if the data were available.

EXPERT OPINION

The current status of fungal infections and the drawbacks of existing drugs have encouraged scientists to find novel scaffolds based on different methods like virtual screening and fragment-based drug discovery. Machine learning and in-silico methods have found their role in this field and experts are hopeful to find novel scaffolds/compounds by using these methods.

New N-Alkylated Heterocyclic Compounds as Prospective NDM1 Inhibitors: Investigation of In Vitro and In Silico Properties

A new family of pyrazole-based compounds (1–15) was synthesized and characterized using different physicochemical analyses, such as FTIR, UV-Visible, ¹H, ¹³C NMR, and ESI/LC-MS. The compounds were evaluated for their in vitro antifungal and antibacterial activities against several fungal and bacterial strains. The results indicate that some compounds showed excellent antibacterial activity against E. coli, S. aureus, C. freundii, and L. monocytogenes strains. In contrast, none of the compounds had antifungal activity. Molecular electrostatic potential (MEP) map analyses and inductive and mesomeric effect studies were performed to study the relationship between the chemical structure of our compounds and the biological activity. In addition, molecular docking and virtual screening studies were carried out to rationalize the antibacterial findings to characterize the modes of binding of the most active compounds to the active pockets of NDM1 proteins.

Discovery of Potent Dual-Tailed Benzenesulfonamide Inhibitors of Human Carbonic Anhydrases Implicated in Glaucoma and in Vivo Profiling of Their Intraocular Pressure-Lowering Action

The design of three dual-tailed sulfonamide series 11a-11g, 14a-14h, and 16a-16e as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors are presented. All compounds were evaluated for inhibitory action against pharmacologically relevant human CA isoforms I, II, IV, and VII. Compounds 11a-11g emerged as potent CA inhibitors against the four tested isoforms with a significant selectivity to CA II, which is implicated in glaucoma (K_i in the range 0.36-6.9 nM). X-ray crystallographic analysis of three compounds (11a, 11d, and 11g) bound to CA II showed the validity of the adopted drug design strategy as specific moieties within the ligand structure interacted directly with the hydrophobic and hydrophilic halves of the CA II active site. Compounds 11b-11d and 11g were evaluated for their intraocular pressure-lowering effects in a rabbit model of glaucoma. 11b and 11d showed significant efficacy when compared to the clinically used drug dorzolamide.

Novel Sulfones with Antifungal Properties: Antifungal Activities and Interactions with Candida spp. Virulence Factors

Since candidiasis is so difficult to eradicate with an antifungal treatment and the existing antimycotics display many limitations, hopefully new sulfone derivatives may overcome these deficiencies. It is pertinent to study new strategies such as sulfone derivatives targeting the virulence attributes of C. albicans that differentiate them from the host. During infections, the pathogenic potential of C. albicans relies on the virulence factors as follows: hydrolytic enzymes, transcriptional factors, adhesion, and development of biofilms. In the article we explored how the above-presented C. albicans fitness and virulence attributes provided a robust response to the environmental stress exerted by sulfones upon C. albicans; C. albicans fitness and virulence attributes are fungal properties whose inactivation attenuates virulence. Our understanding of how these mechanisms and factors are inhibited by sulfones has increased over the last years. As lack of toxicity is a prerequisite for medical approaches, sulfones (non-toxic as assessed in vitro and in vivo) may prove to be useful for reducing C. albicans pathogenesis in humans. The antifungal activity of sulfones dealing with these multiple virulence factors and fitness attributes is discussed.

Novel 6-Phenylnicotinohydrazide Derivatives: Design, Synthesis and Biological Evaluation as a Novel Class of Antitubercular and Antimicrobial Agents

In our ongoing efforts to develop potent antitubercular agents based on the 6-phenylnicotinohydrazide, herein we report the design, synthesis and biological evaluation of three sets of 6-phenylnicotinohydrazide derivatives 8a-g, 12 and 16a, b. The designed compounds were synthesized and in vitro evaluated for their antitubercular activity. In addition, their antifungal and antibacterial activities were evaluated as well. The nicotinohydrazide class displayed different levels of antimicrobial activity and possessed a distinctive pattern of selectivity against the tested microorganisms. However, the 2,6-dichlorobenzylidene counterpart 8b emerged as the most active one in this study, with superior antimycobacterial activity (minimum inhibitory concentration (MIC)=3.90 µg/mL) and potent broad-spectrum antimicrobial activities with MIC range of 0.24-1.95 µg/mL. The structure-activity relationship for such nicotinohydrazides has been established. Further, the cytotoxicity of the most active antitubercular compounds 8b, d and g were tested against the normal breast cells WI-38; none of them displayed significant cytotoxic effect, thereby providing a good therapeutic index.

Novel Thiazolidinone/Thiazolo[3,2-a]Benzimidazolone-Isatin Conjugates as Apoptotic Anti-proliferative Agents Towards Breast Cancer: One-Pot Synthesis and In Vitro Biological Evaluation

In connection with our research program on the development of new isatin-based anticancer candidates, herein we report the synthesis of two novel series of thiazolidinone-isatin conjugates (4a⁻n) and thiazolo[3,2-a]benzimidazolone-isatin conjugates (7a⁻d), and in vitro evaluation of their antiproliferative activity towards two breast cancer cell lines; triple negative MDA-MB-231, and MCF-7. Compounds 4m and 7b emerged as the most active congeners against MDA-MB-231 cells (IC50 = 7.6 ± 0.5 and 13.2 ± 1.1 µM, respectively). Compounds 4m and 7b were able to provoke apoptosis in MDA-MB-231 cells, evidenced by the up-regulation of Bax and down-regulation of Bcl-2, besides boosting caspase-3 levels. Hybrid 4m induced a fourfold increase in the percentage of cells at Sub-G₁, with concurrent arrest in G₂-M phase by 2.5-folds. Furthermore, hybrid 4m resulted in a sixfold increase in the percentage of annexin V-FITC positive apoptotic MDA-MB-231 cells as compared with the control. Moreover, the cytotoxic activities of the active conjugates were assessed towards two nontumorigenic cell lines (breast MCF-10A and lung WI-38) where both conjugates 4m and 7b displayed mean tumor selectivity index: 9.6 and 13.9, respectively. Finally, several ADME descriptors were predicted for the active conjugates via a theoretical kinetic study.

Dual-tail arylsulfone-based benzenesulfonamides differently match the hydrophobic and hydrophilic halves of human carbonic anhydrases active sites: Selective inhibitors for the tumor-associated hCA IX isoform

The synthesis and characterization of two new sets of arylsulfonehydrazone benzenesulfonamides (4a-4i with phenyl tail and 4j-4q with tolyl tail) are reported. The compounds were designed according to a dual-tails approach to modulate the interactions of the ligands portions at the outer rim of both hydrophobic and hydrophilic active site halves of human isoforms of carbonic anhydrase (CA, EC 4.2.1.1). The synthesized sulfonamides were evaluated in vitro for their inhibitory activity against the following human (h) isoforms, hCA I, II, IV and IX. With the latter being a validated anticancer drug target and a marker of tumor hypoxia, attractive results arose from the Compounds' inhibitory screening in terms of potency and selectivity. Indeed, whereas the first subset of compounds 4a-4i exhibited great efficacy in inhibiting both the ubiquitous, off-target hCA II (KIs 9.5-172.0 nM) and hCA IX (KIs 7.5-131.5 nM), the second subset of tolyl-bearing derivatives 4j-4q were shown to possess a selective hCA IX inhibitory action over isoforms I, II and IV. The most selective compounds 4l and 4n were further screened for their in vitro cytotoxic activity against MCF-7 and MDA-MB-231 cancer cell lines under hypoxic conditions. The selective IX/II inhibitory trend of 4j-4q compared to those of compounds 4a-4i was unveiled by docking studies. Further exploration of these molecules could be useful for the development of novel antitumor agents with a selective CA inhibitory mechanism.

Synthesis and biological evaluation of 2-aminothiazole-thiazolidinone conjugates as potential antitubercular agents

AIM

Mycobacterium tuberculosis, which causes tuberculosis, continues to infect millions of the global population, resulting in 1.8 million deaths worldwide in 2015.

METHODOLOGY

Hybrids of 2-amino-4-methylthiazole bearing 5-acetyl/5-ethyl carboxylate functionality with 5-arylidene thiazolidinone moiety (6a-k and 9a-d) were synthesized and screened for antitubercular and antimicrobial activities.

RESULTS & DISCUSSION

5-ethyl carboxylate derivative 6k revealed half antitubercular activity (minimal inhibitory concentration = 1.56 μg/ml) than the acetyl analog 6c (minimal inhibitory concentration = 0.78 μg/ml), however, it exhibited more potent broad spectrum antibacterial and antifungal activities in addition to its excellent safety profile with high selectivity toward M. tuberculosis over normal human lung cells. Collectively, these data suggested that compound 6k can be considered as an ideal lead compound for further optimization.

Integration of oxidative arylation with sulfonyl migration: one-pot tandem synthesis of densely functionalized (NH)-pyrroles

A one-pot synthesis of 2-aryl-3-alkyl/aryl-sulfonyl-(NH)-pyrroles from N-sulfonylpyrroles, developed for the first time, via palladium-catalyzed oxidative C-2 arylation followed by sulfonyl migration is described.