Novel 2-indolinones containing a sulfonamide moiety as selective inhibitors of candida β-carbonic anhydrase enzyme

One-pot synthesis, molecular docking, ADMET, and DFT studies of novel pyrazolines as promising SARS-CoV-2 main protease inhibitors

Pyrazoline and its derivatives have numerous prominent pharmacological effects. Focusing on its anti-viral property, we have designed and synthesized three novel pyrazoline derivatives (A1–A3) through one-pot three components and characterized them using different spectroscopic techniques (FT-IR, ¹H NMR, ¹³C NMR, and UV). These compounds were evaluated against SARS-CoV-2 main protease utilizing in-silico molecular docking studies. The docking results displayed good inhibitory activity of the synthesized compounds. Among them, compound A2 was the most active against targeted protein. The drug-likeness and ADMET properties were predicted to have varied profiles but could still be developed, especially A2. DFT/TD-DFT calculations through B3LYP/6-311G++ level of theory were applied to provide comparable theoretical data along with MEP map and electronic energy gap of HOMO → LUMO.

Biological investigation of N-methyl thiosemicarbazones as antimicrobial agents and bacterial carbonic anhydrases inhibitors

The enormous burden of the COVID-19 pandemic in economic and healthcare terms has cast a shadow on the serious threat of antimicrobial resistance, increasing the inappropriate use of antibiotics and shifting the focus of drug discovery programmes from antibacterial and antifungal fields. Thus, there is a pressing need for new antimicrobials involving innovative modes of action (MoAs) to avoid cross-resistance rise. Thiosemicarbazones (TSCs) stand out due to their easy preparation and polypharmacological application, also in infectious diseases. Recently, we reported a small library of TSCs (1–9) that emerged for their non-cytotoxic behaviour. Inspired by their multifaceted activity, we investigated the antibacterial, antifungal, and antidermatophytal profiles of derivatives 1–9, highlighting a new promising research line. Furthermore, the ability of these compounds to inhibit selected microbial and human carbonic anhydrases (CAs) was assessed, revealing their possible involvement in the MoA and a good selectivity index for some derivatives.

Anti-MRSA activity of curcumin in planktonic cells and biofilms and determination of possible action mechanisms

Staphylococcus aureus is a commensal bacterium and opportunistic human pathogen that can cause a wide variety of clinical infections. It is recognized for its ability to acquire antimicrobial resistance, so methicillin-resistant Staphylococcus aureus (MRSA) infections are a global healthcare challenge. Therefore, the development of new therapeutic options and alternative therapies for treatment is necessary. Curcumin, a polyphenolic substance found in the rhizome of turmeric longa L, has been shown to have several therapeutic properties, including antimicrobial activity. The objective of the study was to evaluate the in vitro antibacterial activity of curcumin alone and associated with oxacillin against MRSA strains, to analyze the mechanism of cell death involved in the isolated action of curcumin by means of flow cytometry and molecular docking, and to verify its superbiofilm action. Curcumin showed antibacterial activity in the range of 125-500 μg/mL against the tested strains, since it caused an increase in membrane permeability and DNA fragmentation, as revealed by flow cytometry analysis. Moreover, it was possible to observe interactions of curcumin with wild-type S. aureus DHFR, S. aureus gyrase and S. aureus gyrase complex with DNA, DNA (5'-D(*CP*GP*AP*TP*GP*CP*G)-3') and Acyl-PBP2a from MRSA by molecular docking. Curcumin also had a synergistic and additive effect when associated with oxacillin, and significantly reduced the cell viability of the analyzed biofilms. Thus, curcumin is a possible candidate for pharmaceutical formulation development for the treatment of MRSA infections.

Probing 4-(diethylamino)-salicylaldehyde-based thiosemicarbazones as multi-target directed ligands against cholinesterases, carbonic anhydrases and α-glycosidase enzymes

With the fading of 'one drug-one target' approach, Multi-Target-Directed Ligands (MTDL) has become a central idea in modern Medicinal Chemistry. The present study aimed to design, develop and characterize a novel series of 4-(Diethylamino)-salicylaldehyde based thiosemicarbazones (3a-p) and evaluates their biological activity against cholinesterase, carbonic anhydrases and α-glycosidase enzymes. The hCA I isoform was inhibited by these novel 4-(diethylamino)-salicylaldehyde-based thiosemicarbazones (3a-p) in low nanomolar levels, the Ki of which differed between 407.73 ± 43.71 and 1104.11 ± 80.66 nM. Against the physiologically dominant isoform hCA II, the novel compounds demonstrated K_is varying from 323.04 ± 56.88 to 991.62 ± 77.26 nM. Also, these novel 4-(diethylamino)-salicylaldehyde based thiosemicarbazones (3a-p) effectively inhibited AChE, with Ki values in the range of 121.74 ± 23.52 to 548.63 ± 73.74 nM. For BChE, Ki values were obtained with in the range of 132.85 ± 12.53 to 618.53 ± 74.23 nM. For α-glycosidase, the most effective Ki values of 3b, 3k, and 3g were with Ki values of 77.85 ± 10.64, 96.15 ± 9.64, and 124.95 ± 11.44 nM, respectively. We have identified inhibition mechanism of 3b, 3g, 3k, and 3n on α-glycosidase AChE, hCA I, hCA II, and BChE enzyme activities. Hydrazine-1-carbothioamide and hydroxybenzylidene moieties of compounds play an important role in the inhibition of AChE, hCA I, and hCA II enzymes. Hydroxybenzylidene moieties are critical for inhibition of both BChE and α-glycosidase enzymes. The findings of in vitro and in silico evaluations indicate 4-(diethylamino)-salicylaldehyde-based thiosemicarbazone scaffold to be a promising hit for drug development for multifactorial diseases like Alzheimer's disease.

Virtual screening based on molecular docking of possible inhibitors of Covid-19 main protease

Coronavirus (COVID-19) is an enveloped RNA virus that is diversely found in humans and that has now been declared a global pandemic by the World Health Organization. Thus, there is an urgent need to develop effective therapies and vaccines against this disease. In this context, this study aimed to evaluate in silico the molecular interactions of drugs with therapeutic indications for treatment of COVID-19 (Azithromycin, Baricitinib and Hydroxychloroquine) and drugs with similar structures (Chloroquine, Quinacrine and Ruxolitinib) in docking models from the SARS-CoV-2 main protease (M-pro) protein. The results showed that all inhibitors bound to the same enzyme site, more specifically in domain III of the SARS-CoV-2 main protease. Therefore, this study allows proposing the use of baricitinib and quinacrine, in combination with azithromycin; however, these computer simulations are just an initial step for conceiving new projects for the development of antiviral molecules.

Inhibition of the newly discovered β‑carbonic anhydrase from the protozoan pathogen Trichomonas vaginalis with inorganic anions and small molecules

The protozoan pathogen Trichomonas vaginalis encodes two carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the β-class. One of these enzymes, T. vaginalis carbonic anhydrase 1 (TvaCA1), was recently cloned and characterized by our group, and its X-ray crystal structure reported. No inhibitors of this enzyme were reported up until now. Here we investigated the inhibition of TvaCA1 with inorganic anions and small molecules and observed that thiocyanate, cyanide, selenite, selenocyanate and divanadate are sub-millimolar inhibitors, whereas sulfamide, sulfate, phenylboronic acid and phenylarsonic acid are micromolar inhibitors. Finding effective TvaCA1 inhibitors may be useful for developing new antiprotozoan drugs.

Development of Thiazolidinones as Fungal Carbonic Anhydrase Inhibitors

In our efforts to find new and selective thiazolidinone-based anti-Candida agents, we synthesized and tested 26 thiazolidinones against several Candida spp. and Gram-positive and Gram-negative bacteria. The compounds showed selective antifungal activity with potency similar to fluconazole and clotrimazole, while lacking strong antibacterial activity. Molecular docking and molecular dynamics studies were performed on Candida CYP51a1 and carbonic anhydrase (CA) enzymes to further suggest putative targets that could mediate the antifungal effects of these compounds. Finally, the compounds were tested in enzyme inhibition assays to assess their putative mechanism of action and showed promising K_I values in the 0.1–10 µM range against the Candida glabrata β-CA enzyme CgNce103.

rac- and meso-Cyclohexanoids: Their α-, β-glycosidases, antibacterial, antifungal activities, and molecular docking studies

An efficient and versatile synthesis method has been postulated for hydroxymethylated rac- and meso-cyclohexanoid derivatives. The synthesis of these stereoisomers was achieved easily with traditional methods using hexahydroisobenzofuran 6, prepared from commercially available cis-hydrophthalic anhydride. The study, involving diastereoselective epoxidation and cis-hydroxylation, was conducted to obtain epoxy-, cis-, and trans-diol-furans 7, 8, and 9. After sulfamic acid-catalyzed ring-opening reaction of the epoxide and furan rings, rac- and meso-tetraacetates 14, 15, and 16 were afforded. Hydrolysis of acetate groups with ammonia in absolute methanol yielded the desired tetrols rac-17, meso-18, and meso-19. All structures, after purification by chromatographic methods and elucidation by spectral techniques, were screened against α- and β-glucosidases. Compounds 7, 8, 10, 17, 18, and 19 were also evaluated for their antibacterial and antifungal activity against some selected synthesized compounds with varying degrees of inhibitory effects on the growth of different pathogenic microorganisms by the well-diffusion method. In addition, Saccharomyces cerevisiae α-glucosidase molecular modeling studies were performed for all rac- and meso-compounds 7, 8, 10, 17, 18, and 19.

Mycobacterium tuberculosis β-Carbonic Anhydrases: Novel Targets for Developing Antituberculosis Drugs

The genome of Mycobacterium tuberculosis (Mtb) encodes three β-carbonic anhydrases (CAs, EC 4.2.1.1) that are crucial for the life cycle of the bacterium. The Mtbβ-CAs have been cloned and characterized, and the catalytic activities of the enzymes have been studied. The crystal structures of two of the enzymes have been resolved. In vitro inhibition studies have been conducted using different classes of carbonic anhydrase inhibitors (CAIs). In vivo inhibition studies of pathogenic bacteria containing β-CAs showed that β-CA inhibitors effectively inhibited the growth of pathogenic bacteria. The in vitro and in vivo studies clearly demonstrated that β-CAs of not only mycobacterial species, but also other pathogenic bacteria, can be targeted for developing novel antimycobacterial agents for treating tuberculosis and other microbial infections that are resistant to existing drugs. In this review, we present the molecular and structural data on three β-CAs of Mtb that will give us better insights into the roles of these enzymes in pathogenic bacterial species. We also present data from both in vitro inhibition studies using different classes of chemical compounds and in vivo inhibition studies focusing on M. marinum, a model organism and close relative of Mtb.