Gp41 inhibitory activity prediction of theaflavin derivatives using ligand/structure-based virtual screening approaches

Computational study on Schiff base derived salicylaldehyde and furfuraldehyde derivatives as potent anti-tubercular agents: prospect to dihydropteroate synthase inhibitors

Nowadays, bacterial multidrug resistance has become a commonplace problem in clinics due to several intrinsic factors mediated through resistance to antibacterials obtained via bacterial consortia and extrinsic factors, such as non-uniform antibacterial policy and migration of resistant bacteria through human and other routes. The development of newer, effective anti-mycobacterial candidate(s) is coveted by clinics. Hybrid molecules would be comparatively more emulating against invasive bacterial strains; nevertheless, newer antibiotics are continually added. Herein, designing and developments of two series of Schiff-based salicylaldehyde S1-S7 and furfuraldehyde F1-F7 molecules individually bearing sulfonamide group are described; and those were synthesized and their structures by spectral characterization were confirmed. Concomitantly, molecule dynamic simulations of all atoms had been performed to fathom the mechanism of the action with these leading complexes. These data imply that the synthesized Schiff-based salicylaldehyde hybrids would be promising anti-tubercular compounds, which further need potent pharmacological evaluations.Communicated by Ramaswamy H. Sarma.

Discovery of novel RARα agonists using pharmacophore-based virtual screening, molecular docking, and molecular dynamics simulation studies

Nuclear retinoic acid receptors (RARs) are ligand-dependent transcription factors involved in various biological processes, such as embryogenesis, cell proliferation, differentiation, reproduction, and apoptosis. These receptors are regulated by retinoids, i.e., retinoic acid (RA) and its analogs, as receptor agonists. RAR agonists are promising therapeutic agents for the treatment of serious dermatological disorders, including some malignant conditions. By inducing apoptosis, they are able to inhibit the proliferation of diverse cancer cell lines. Also, RAR agonists have recently been identified as therapeutic options for some neurodegenerative diseases. These features make retinoids very attractive molecules for medical purposes. Synthetic selective RAR agonists have several advantages over endogenous ones, but they suffer poor pharmacokinetic properties. These compounds are normally lipophilic acids with unfavorable drug-like features such as poor oral bioavailability. Recently, highly selective, potent, and less toxic RAR agonists with proper lipophilicity, thus, good oral bioavailability have been developed for some therapeutic applications. In the present study, ligand and structure-based virtual screening technique was exploited to introduce some novel RARα agonists. Pharmacokinetic assessment was also performed in silico to suggest those compounds which have optimized drug-like features. Finally, two compounds with the best in silico pharmacological features are proposed as lead molecules for future development of RARα agonists.

Synthesis, Molecular Docking and Molecular Dynamics Simulation of 2- Thioxothiazolidin-4-One Derivatives against Gp41

INTRODUCTION

Gp41 and its conserved hydrophobic groove on the N-terminal heptad repeat region are attractive targets in the design of HIV-1 entry inhibitors. Linearly extended molecules have shown potent anti-HIV-1 activity for their effective interactions with the gp41 binding pocket. Rhodanine ring attached to substituted pyrrole or furan rings has been proved a preferred moiety to be inserted inside the molecular structure of the gp41 inhibitors.

OBJECTIVES

Based on the previous findings we are going to describe some rhodanine derivatives in which a substituted imidazole ring is introduced in place of the pyrrole or furan rings. The compounds' flexibility is increased by inserting methylene groups inside the main scaffold.

METHODS

Molecular docking and molecular dynamics simulations approaches were exploited to investigate the chemical interactions and the stability of the designed ligands-gp41 complex. All compounds were synthesized and their chemical structures were elucidated by 1HNMR, 13CNMR, FTIR and Mass spectroscopy. Biological activities of the compounds against HIV-1 and HIV-2 and their cellular toxicities against the T-lymphocyte (MT-4) cell line were determined.

RESULTS

All the designed compounds showed proper and stable chemical interactions with gp41 according to the in silico studies. The results of the biological tests proved none of the compounds active against HIV-1 replication in cell cultures.

CONCLUSION

Since all the studied compounds were potently toxic for the host cell; it was therefore not possible to assess their anti-HIV activities.

Identification of Theaflavin-3,3'-Digallate as a Novel Zika Virus Protease Inhibitor

Mounting evidence indicates that Zika virus (ZIKV) is closely related to neurological disorders such as microcephaly and Guillain-Barré syndrome. There are currently no effective vaccines and FDA-approved inhibitors against ZIKV infection. The flaviviral heterodimeric serine protease NS2B-NS3 plays an essential role in ZIKV maturation and replication, thus becoming a promising target in anti-ZIKV therapy. Herein, we developed a fluorescence-based screening assay to search for inhibitors targeting the ZIKV NS2B-NS3 protease (ZIKVpro), and identified theaflavin-3,3’-digallate (ZP10), a natural active compound derived from black tea, as a potent ZIKV protease inhibitor in vitro (IC_{50 =} 2.3 μM). ZP10 exhibited dose-dependent inhibitory effect on ZIKV replication (EC_{50 =} 7.65 μM). Western blot analysis suggested that ZP10 inhibited the cleavage processing of viral polyprotein precursor in cells either infected with ZIKV or expressing minimal self-cleaving proteinase NS2B-3 protease, resulting in inhibition of virus growth. Moreover, ZP10 was showed to directly bind to ZIKVpro, and a docking model further revealed that ZP10 interacted with several critical residues at the proteolytic cavity of the ZIKVpro. This study highlights that ZP10 has anti-ZIKV potency through ZIKVpro inhibition, which indicates its potential application in anti-ZIKV therapy.