DprE1 Inhibitors: Enduring Aspirations for Future Antituberculosis Drug Discovery

DprE1 is a crucial enzyme involved in the cell wall synthesis of Mycobacterium tuberculosis and a promising target for antituberculosis drug development. However, its unique structural characteristics for ligand binding and association with DprE2 make developing new clinical compounds challenging. This review provides an in-depth analysis of the structural requirements for both covalent and non-covalent inhibitors, their 2D and 3D binding patterns, as well as their biological activity data in vitro and in vivo, including pharmacokinetic information. We also introduce a protein quality score (PQS) and an active-site map of the DprE1 enzyme to help medicinal chemists better understand DprE1 inhibition and develop new and effective anti-TB drugs. Furthermore, we examine the resistance mechanisms associated with DprE1 inhibitors to understand future developments due to resistance emergence. This comprehensive review offers insight into the DprE1 active site, including protein-binding maps, PQS, and graphical representations of known inhibitors, making it a valuable resource for medicinal chemists working on future antitubercular compounds.

Computational studies indicated the effectiveness of human metabolites against SARS-Cov-2 main protease

To fight against the devastating coronavirus disease 2019 (COVID-19), identifying robust anti-SARS-CoV-2 therapeutics from all possible directions is necessary. To contribute to this effort, we selected a human metabolites database containing waters and lipid-soluble metabolites to screen against the 3-chymotrypsin-like proteases (3CLpro) protein of SARS-CoV-2. The top 8 hits from virtual screening displayed a docking score varying between ~ - 11 and ~ - 14 kcal/mol. Molecular dynamics simulations complement the virtual screening study in conjunction with the molecular mechanics generalized Born surface area (MM/GBSA) scheme. Our analyses revealed that (HMDB0132640) has the best glide docking score, - 14.06 kcal/mol, and MM-GBSA binding free energy, - 18.08 kcal/mol. The other three lead molecules are also selected along with the top molecule through a critical inspection of their pharmacokinetic properties. HMDB0132640 displayed a better binding affinity than the other three compounds (HMDB0127868, HMDB0134119, and HMDB0125821) due to increased favorable contributions from the intermolecular electrostatic and van der Waals interactions. Further, we have investigated the ligand-induced structural dynamics of the main protease. Overall, we have identified new compounds that can serve as potential leads for developing novel antiviral drugs against SARS-CoV-2 and elucidated molecular mechanisms of their binding to the main protease. Identification of probable hits from human metabolites against SARS-CoV-2 using integrated computational approaches-Missed against MS.

Ethyl Pyruvate as a Potential Defense Intervention against Cytokine Storm in COVID-19?

COVID-19 is a deadly pandemic and has resulted in a huge loss of money and life in the past few months. It is well known that the SARS-CoV-2 gene mutates relatively slowly as compared to other viruses but still may create hurdles in developing vaccines. Therefore, there is a need to develop alternative routes for its management and treatment of COVID-19. Based on the severity of viral infection in COVID-19 patients, critically ill patients (∼5%, with old age, and comorbidities) are at high risk of morbidities. The reason for this severity in such patients is attributed to "misleading cytokine storm", which produces ARDS and results in the deaths of critically ill patients. In this connection, ethyl pyruvate (EP) controls these cytokines/chemokines, is an anti-inflammatory agent, and possesses a protective effect on the lungs, brain, heart, and mitochondria against various injuries. Considering these facts, we propose that the site-selective EP formulations (especially aerosols) could be the ultimate adjuvant therapy for the regulation of misleading cytokine storm in severely affected COVID-19 patients and could reduce the mortalities.

Expansion of a novel lead targeting M. tuberculosis DHFR as antitubercular agents

A series of 1-(1-benzyl-2-methyl-5-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)-1H-indol-3-yl)ethanone and ethyl 1-benzyl-2-methyl-5-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)-1H-indole-3-carboxylate derivatives were designed based on bioisosteric replacement of previously reported antitubercular agent (IND-07). Twenty ligands were successfully synthesized and some of them were found to have good in vitro activity (MIC < 10 μM) against the H₃₇Rv strain of Mycobacterium tuberculosis. Among these compounds, KC-08 and KC-11 inhibited Mtb-DHFR with 4- and 18-fold selectivity for Mtb-DHFR over h-DHFR, respectively. Compound KC-11 display acceptable ADME, and better pharmacokinetic profiles than IND-07. Docking studies were performed to predict the binding mode of the compounds within the active site of Mtb-DHFR and h-DHFR. The results of our study suggest that compound KC-11 may serve as a valuable lead for the design and development of selective inhibitors of Mtb-DHFR with potential therapeutic application in tuberculosis.

Pyrazole-pyrazoline as promising novel antimalarial agents: A mechanistic study

A series of pyrazole-pyrazoline substituted with benzenesulfonamide were synthesized and evaluated for their antimalarial activity in vitro and in vivo. The compounds were active against both chloroquine (CQ) sensitive (3D7) and CQ resistant (RKL-9) strains of Plasmodium falciparum. Seven compounds (7e, 7i, 7j, 7l, 7m, 7o and 7p) exhibiting EC50 less than 2 μM. A mechanistic study of compound 7o revealed that these compound act through the inhibition of β-hematin. The study indicated that these compounds can serve as lead compounds for further development of potent antimalarial drugs.

Recent updates on biological activities of oxadiazoles

Among the plethora of heterocyclic nucleus discovered, the oxadiazoles have also been explored extensively. The oxadiazole structure has been demonstrated to bear important biological activities such as anti-cancer, antiinflammatory, anti-tuberculosis, anti-malarial and anti-schistosomiasis etc. The presence of oxadiazole motifs in diverse types of compounds proves its importance in the field of medicinal chemistry. This review is complementary to earlier reviews and covers recent updates of various pharmacological aspects of oxadiazoles. To help the reader better know the context for these approaches, a summary of various aspects of background of related topic is presented.

Structure based virtual screening of MDPI database: discovery of structurally diverse and novel DPP-IV inhibitors

Inhibition of dipeptidyl peptidase IV (DPP-IV) has been emerged as a promising approach for the treatment of type 2 diabetes (T2D). Structure based virtual screening (SBVS) of Molecular Diversity Preservation International (MDPI) database was performed using Glide and Gold against DPP-IV enzyme. Six promising hits were identified and tested for DPP-IV inhibition. Three compounds were found to be active at low micromolar concentration. The 3-(1-hydrazinyl-1-(phenylamino)ethyl)-4-hydroxy-1-methylquinolin-2(1H)-one (compound A) was found to be the most potent hit with an IC50 of 0.73 μM. These three compounds (A, B and D) were then assessed for their glucose lowering effects in glucose fed hyperglycemic female Wistar rats. The glucose lowering effects of compounds also confirms their potential as anti-diabetic agents. The present study demonstrates a successful utilization of in silico SBVS tools in identification of novel and potential DPP-IV inhibitor.

Novel hydrazine derivatives as selective DPP-IV inhibitors: findings from virtual screening and validation through molecular dynamics simulations

The present study demonstrates and validates the discovery of two novel hydrazine derivatives as selective dipeptidyl peptidase-IV (DPP-IV) inhibitors. Virtual screening (VS) of publicly available databases was performed using virtual screening workflow (VSW) of Schrödinger software against DPP-IV and the most promising hits were selected. Selectivity was further assessed by docking the hits against homology modeled structures of DPP8 and DPP9. Two novel hydrazine derivatives were selected for further studies based on their selectivity threshold. To assess their correct binding modes and stability of their complexes with enzyme, molecular dynamic (MD) simulation studies were performed against the DPP-IV protein and the results revealed that they had a better binding affinity towards DPP-IV as compared to DPP 8 and DPP 9. The binding poses were further validated by docking these ligands with different softwares (Glide and Gold). The proposed binding modes of hydrazines were found to be similar to sitagliptine and alogliptine. Thus, the study reveals the potential of hydrazine derivatives as highly selective DPP-IV inhibitors.