In Silico Exploration for New Antimalarials: Arylsulfonyloxy Acetimidamides as Prospective Agents

A strategy is described to identify new antimalarial agents to overcome the drug resistance and/or failure issues through in silico screening of multiple biological targets. As a part of this, three enzymes namely CTPS, CK, and GST were selected, from among 56 drug targets of P. falciparum, and used them in virtual screening of ZINC database entries which led to the design and synthesis of arylsulfonyloxy acetimidamides as their consensus inhibitors. From these, two compounds showed good activity against sensitive (3D7; IC₅₀, 1.10 and 1.45 μM) and resistant (K1; IC₅₀, 2.10 and 2.13 μM) strains of the parasite, and they were further investigated through docking and molecular dynamics simulations. The findings of this study collectively paved the way for arylsulfonyloxy acetimidamides as a new class of antimalarial agents

N-acetyl cysteine: A tool to perturb SARS-CoV-2 spike protein conformation

The infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) resulted in a pandemic with huge death toll and economic consequences. The virus attaches itself to the human epithelial cells through noncovalent bonding of its spike protein with the angiotensin-converting enzyme-2 (ACE2) receptor on the host cell. We hypothesized that perturbing the functionally active conformation of spike protein through reduction of its solvent accessible disulfide bond, thereby disintegrating its structural architecture, may be a feasible strategy to prevent infection. Proteomics data showed that N-acetyl cysteine (NAC), an antioxidant and mucolytic agent been widely in use in clinical medicine, forms covalent conjugates with solvent accessible cysteine residues of spike protein that were disulfide bonded in the native state. In silico analysis indicated that this covalent conjugation perturbed the stereo specific orientations of the interacting key residues of spike protein that resulted in threefold weakening in the binding affinity of spike protein with ACE2 receptor. Antiviral assay using VeroE6 cells showed that NAC caused 54.3% inhibition in SARS-CoV-2 replication. Interestingly, almost all SARS-Cov-2 variants conserved cystine residues in the spike protein. Our observed results open avenues for exploring in vivo pharmaco-preventive and therapeutic potential of NAC for Coronavirus Disease 2019 (COVID-19).</p