Quinapril for COVID-19

Abstract To date, COVID-19 continues to pose a global health challenge, with substantial morbidity, mortality, and long-term post-COVID-19 complications threatening public health resilience. During the early pandemic, the IL-6 inhibitor (tocilizumab) was the widely used approved immunotherapy for critically ill patients; however, a subset of ICU cases exhibited normal interleukin-6 (IL-6) levels and failed to respond. We hypothesized that interleukin-17 (IL-17), which acts synergistically with IL-6, contributes to cytokine storm progression and severe inflammation. Our study uniquely integrates a clinical cross-sectional analysis with advanced in-silico modelling, directly linking patient-derived biomarker, radiological, and statistical data to molecular-level mechanisms of COVID-19 severity. Serum IL-17 was significantly elevated in critical versus moderate COVID-19 cases, with a threshold of 187.9 ng/mL predicting poor outcomes by ROC analysis. Logistic regression identified age and monocytes as independent predictors of severity, supporting a combined biomarker approach for improving the prognosis and clinical outcomes. Radiological findings, including ground-glass opacities and consolidations, alongside hematological abnormalities, were more frequent in critical cases. Computational docking revealed key amino acid residues—particularly asparagine (Asn) and cysteine (Cys)—as structural determinants shared by SARS-CoV-2 spike protein and human inflammatory mediators (IL-17R, IL-6R, CD41/CD61, CD47/SIRP). Asparaginase (ASNase) targeted critical residues such as the invariant gate residue “Asn343” and Cys213 of spike protein, Asn240 of IL-17R, and Asn136 of IL-6R. Several phytochemicals, including phytic acid and amygdalin, as well as synthetic agents such as candesartan, remdesivir, and enalapril, were found to preferentially bind to cysteine (Cys) residues—and, to a lesser extent, asparagine (Asn) residues—within key binding interfaces, in addition to targeting B-cell epitopes. This conserved residue preference supports the rationale for a dual-action therapeutic strategy in which asparaginase (ASNase) is combined with selected plant-derived ligands to simultaneously disrupt viral entry mechanisms and attenuate the inflammatory signalling. This dual-perspective approach not only identified IL-17 and IL-6 as independent severity predictors but also revealed conserved Asn and Cys motifs as critical therapeutic targets, leading to novel strategies—such as ASNase, synthetic agents and phytochemical combinations—for simultaneously blocking viral entry and modulating hyperinflammatory pathways. These findings warrant rigorous experimental and clinical validation to facilitate translation into effective therapeutic interventions.

AbstractTo attain promising pharmacotherapies, researchers have applied drug repurposing (DR) techniques to discover the candidate medicines to combat the coronavirus disease 2019 (COVID-19) outbreak. Although many DR approaches have been introduced for treating different diseases, only structure-based DR (SBDR) methods can be employed as the first therapeutic option against the COVID-19 pandemic because they rely on the rudimentary information about the diseases such as the sequence of the severe acute respiratory syndrome coronavirus 2 genome. Hence, to try out new treatments for the disease, the first attempts have been made based on the SBDR methods which seem to be among the proper choices for discovering the potential medications against the emerging and re-emerging infectious diseases. Given the importance of SBDR approaches, in the present review, well-known SBDR methods are summarized, and their merits are investigated. Then, the databases and software applications, utilized for repurposing the drugs against COVID-19, are introduced. Besides, the identified drugs are categorized based on their targets. Finally, a comparison is made between the SBDR approaches and other DR methods, and some possible future directions are proposed.

The SARS coronavirus 2 (SARS-CoV-2) has caused an ongoing global pandemic with currently 29 million confirmed cases and close to a million deaths. At this time, there are no FDA-approved vaccines or therapeutics for COVID-19, but Emergency Use Authorization has been granted for remdesivir, a broad-spectrum antiviral nucleoside analog. However, remdesivir is only moderately efficacious against SARS-CoV-2 in the clinic, and improved treatment strategies are urgently needed. To accomplish this goal, we devised a strategy to identify compounds that act synergistically with remdesivir in preventing SARS-CoV-2 replication. We conducted combinatorial high-throughput screening in the presence of submaximal remdesivir concentrations, using a human lung epithelial cell line infected with a clinical isolate of SARS-CoV-2. We identified 20 approved drugs that act synergistically with remdesivir, many with favorable pharmacokinetic and safety profiles. Strongest effects were observed with established antivirals, Hepatitis C virus nonstructural protein 5 A (HCV NS5A) inhibitors velpatasvir and elbasvir. Combination with their partner drugs sofosbuvir and grazoprevir further increased efficacy, increasing remdesivir’s apparent potency 25-fold. We therefore suggest that the FDA-approved Hepatitis C therapeutics Epclusa (velpatasvir/sofosbuvir) and Zepatier (elbasvir/grazoprevir) should be fast-tracked for clinical evaluation in combination with remdesivir to improve treatment of acute SARS-CoV-2 infections.

AbstractSARS coronavirus 2 (SARS-CoV-2) has caused an ongoing global pandemic with significant mortality and morbidity. At this time, the only FDA-approved therapeutic for COVID-19 is remdesivir, a broad-spectrum antiviral nucleoside analog. Efficacy is only moderate, and improved treatment strategies are urgently needed. To accomplish this goal, we devised a strategy to identify compounds that act synergistically with remdesivir in preventing SARS-CoV-2 replication. We conducted combinatorial high-throughput screening in the presence of submaximal remdesivir concentrations, using a human lung epithelial cell line infected with a clinical isolate of SARS-CoV-2. This identified 20 approved drugs that act synergistically with remdesivir, many with favorable pharmacokinetic and safety profiles. Strongest effects were observed with established antivirals, Hepatitis C virus nonstructural protein 5A (HCV NS5A) inhibitors velpatasvir and elbasvir. Combination with their partner drugs sofosbuvir and grazoprevir further increased efficacy, increasing remdesivir’s apparent potency > 25-fold. We report that HCV NS5A inhibitors act on the SARS-CoV-2 exonuclease proofreader, providing a possible explanation for the synergy observed with nucleoside analog remdesivir. FDA-approved Hepatitis C therapeutics Epclusa® (velpatasvir/sofosbuvir) and Zepatier® (elbasvir/grazoprevir) could be further optimized to achieve potency and pharmacokinetic properties that support clinical evaluation in combination with remdesivir.