HIGH-THROUGHPUT SCREENING AND DYNAMIC STUDIES OF SELECTED COMPOUNDS AGAINST SARS-COV-2

Objective: This study was aimed to analyze the inhibitory effect of the drugs used in nanocarrier as well as nanoparticles formulation based drug delivery system selected from PubChem database literature against 3CLpro (3C-like protease) receptor of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) by implementing several in silico analysis techniques. Methods: This paper detailed a molecular docking-based virtual screening of 5240 compounds previously utilized in nanoparticle and nanocarrier drug delivery systems utilizing AutoDock Vina software on 3CL protease to discover potential inhibitors using a molecular docking technique. Results: According to the results of the screening, the top two compounds, PubChem Id 58823276 and PubChem Id 60838 exhibited a high affinity for the 3CL protease binding region. Their binding affinities were-9.6 and-8.5 kJ/mol, indicating that they were tightly bound to the target receptor, respectively. These results outperformed those obtained using the co-crystallized native ligand, which exhibited a binding affinity of-7.4 kJ/mol. PubChem Id 60838, the main hit compound in terms of both binding affinity and ADMET analysis, displayed substantial deformability after MD simulation. As a result of the VS and molecular docking techniques, novel 3CL protease inhibitors from the PubChem database were discovered using the Lipinski rule of five and functional molecular contacts with the target protein, as evidenced by the findings of this work. Conclusion: The findings suggest that the compounds discovered may represent attractive opportunities for the development of COVID-19 3CLpro inhibitors and that they need further evaluation and investigation.

Novel Herbal Formulation Jing Si Exhibits Multiple Functions to Inhibit Replication Activity and Subsides Viral Load of COVID-19 Variants

Background: SARS-CoV-2 is susceptible to frequent mutations and gets transformed into variants therefore identifying novel multi targeting remedies is necessary in formulating strategies to overcome the pandemic. Methods: Traditional Chinese medicine based formula Jing Si herbal (JSH) was screened and analyzed by HPLC to evaluate its ability to act against infection by SARS-CoV-2 variants. The 3CL protease and RdRp assay kit were utilized to detect the enzyme activity. In order to determine the effect of JSH on the binding efficiency and viral penetration of SARS-CoV-2 variants, Calu-3 lung cells and Caco-2 colon cells were infected with fluorescent SARS-CoV-2 pseudo type lentiviruses. In addition, the effect of JSH (16.22 mg /mice/day and 48.66 mg/mice/day) on the viral load in SKH1J mice exposed to inhalation of luminescent SARS-CoV-2 variants for three days was determined. Results: The JSH was found to be effective in inhibiting the viral entry into Calu-3 and Caco-2 cells and in mice pre-treated with JSH for 3 days also inhibited the viral load exposed to different SARS-CoV-2 variants. Interestingly, JSH also decreased 3cL and RdRp activity thereby revealing the multi targeting nature of JSH and therefore will be a potential preventive SARS-CoV-2 infection.Conclusion: Taken together, our present results revealed that JSH could be a potential candidate for COVID-19 treatment.

In silico drug repurposing for the identification of antimalarial drugs as candidate inhibitors of SARS-CoV-2

: Coronavirus disease (COVID-19) is a severe acute respiratory condition that affected millions of populations worldwide in early 2020, indicating for a global health emergency.As regards the deteriorating trends in COVID-19, none of the drugs were confirmed to have substantial efficacy in the potential treatment of COVID-19 patients in large-scale trials.The purpose of this research was to identify potential antimalarial candidate molecules for the treatment of COVID and to evaluate the possible mechanism of action by in silico screening method. Insilicoscreening study of various antimalarial compounds like Amodiaquine, Chloroquine, Hydroxychloroquine, Mefloquine, Primaquine, and Atovaquone were conducted with PyRx and AutoDoc 1.5.6 tools on ACE 2 receptor, 3CL protease, Hemagglutinin esterase, Spike protein SARS HR1 motif and Papain like protease virus proteins.Based on PyRx results, Mefloquine and Atovaquone have higher docking affinity scores against virus proteins compared to other antimalarial compounds. Screening report of Atovaquone exhibited affirmative inhibition constant on Spike protein SARS HR1 motif, 3CL and Papain like protease. In silico analysis reported Atovaquone as a promising candidate for COVID 19 therapy.

Design of D-amino acids SARS-CoV-2 Main protease inhibitors using the cationic peptide from rattlesnake venom as a scaffold

The C30 Endopeptidase (3C-like protease; 3CLpro) is essential for the life cycle of SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) since it plays a pivotal role in viral replication and transcription and is hence a promising drug target. Molecules isolated from animals, insects, plants or microorganisms can serve as a scaffold for the design of novel biopharmaceutical products. Crotamine, a small cationic peptide from the venom of the rattlesnake Crotalus durissus terrificus has been the focus of many studies since it exhibits activities such as analgesic, in vitro antibacterial and hemolytic activities. The crotamine derivative L-peptides (L-CDP) that inhibit the 3CL protease in the low μM range were examined since they are susceptible to proteolytic degradation; we explored the utility of their D-enantiomers form. Comparative uptake inhibition analysis showed D-CDP as a promising prototype for a D-peptide-based drug. We also found that the D-peptides can impair SARS-CoV-2 replication in vivo, probably targeting the viral protease 3CLpro.

503. In vitro Evaluation of Sitagliptin-HIV-1 Trans-activator Transcription Peptide Nano-formula for Antiviral Activity Against SARS-CoV-2: Drug Repurposing Approach

Background The outbreak of COVID-19 pandemic in China regarded as a major health/economic hazard. The importance of coming up with mechanisms for preventing or treating COVID-19 has been felt across the world. This work aimed at examining the efficiency of Sitagliptin (SIT) and human immunodeficiency virus type 1 (HIV-1) trans-activator transcription peptide (TAT) against SARS-CoV-2. Methods SIT-TAT nano-conjugates were prepared according to a full three-factor bi-level (23) factorial design. SIT concentration (mM, X1), TAT concentration (mM, X2), and pH (X3) were selected as the factors. Particle size (nm, Y1) and zeta potential (mV, Y2) were assessed as responses. Characterization of the optimized formula for Fourier-transformed infrared (FTIR) and Transmission electron microscope was carried out. In addition, IC50 in Vero E6 cells, In vitro 3CL-protease inhibition and docking tests were investigated. Results The prepared complex’s formula was as follows 1: 1 SIT: TAT molar ratio, whereas zeta potential and particle size values were at 34.17 mV and 97.19 nm, respectively. This combination did exhibit its antiviral potentiality against SARS-CoV-2 via IC50 values of 9.083 5.415, and 16.14 µM for TAT, SIT-TAT, and SIT, respectively. In addition, the complex SIT-TAT showed a significant (P < 0.001) viral-3CL-protease inhibitory effect (IC50 = 3.959 µM ± 0.011) in comparison to isolated components (IC50 = 10.93 µM ± 0.25) and TAT (IC50 = 8.128 µM ± 0.42). This was further confirmed via in silico study. Molecular docking investigation has shown promising binding affinity of the formula components towards SARS-CoV-2 main protease (3-CL). Conclusion While offering significant binding interactions with protein’s key pocket residues, an optimized formulation of SIT-TAT could guarantee both the enhanced delivery to the target cells and the improved cellular uptake. The presented findings would guarantee further investigations regarding formula optimization against SARS-CoV-2. Disclosures All Authors: No reported disclosures

Preclinical characterization of an intravenous coronavirus 3CL protease inhibitor for the potential treatment of COVID19

COVID-19 caused by the SARS-CoV-2 virus has become a global pandemic. 3CL protease is a virally encoded protein that is essential across a broad spectrum of coronaviruses with no close human analogs. PF-00835231, a 3CL protease inhibitor, has exhibited potent in vitro antiviral activity against SARS-CoV-2 as a single agent. Here we report, the design and characterization of a phosphate prodrug PF-07304814 to enable the delivery and projected sustained systemic exposure in human of PF-00835231 to inhibit coronavirus family 3CL protease activity with selectivity over human host protease targets. Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment.