Nanocurcumin Potently Inhibits SARS-CoV-2 Spike Protein-Induced Cytokine Storm by Deactivation of MAPK/NF-κB Signaling in Epithelial Cells.

Interleukin-mediated deep cytokine storm, an aggressive inflammatory response to SARS-CoV-2 virus infection in COVID-19 patients, is correlated directly with lung injury, multi-organ failure, and poor prognosis of severe COVID-19 patients. Curcumin (CUR), a phenolic antioxidant compound obtained from turmeric (Curcuma longa L.), is well-known for its strong anti-inflammatory activity. However, its in vivo efficacy is constrained due to poor bioavailability. Herein, we report that CUR-encapsulated polysaccharide nanoparticles (CUR-PS-NPs) potently inhibit the release of cytokines, chemokines, and growth factors associated with damage of SARS-CoV-2 spike protein (CoV2-SP)-stimulated liver Huh7.5 and lung A549 epithelial cells. Treatment with CUR-PS-NPs effectively attenuated the interaction of ACE2 and CoV2-SP. The effects of CUR-PS-NPs were linked to reduced NF-κB/MAPK signaling which in turn decreased CoV2-SP-mediated phosphorylation of p38 MAPK, p42/44 MAPK, and p65/NF-κB as well as nuclear p65/NF-κB expression. The findings of the study strongly indicate that organic NPs of CUR can be used to control hyper-inflammatory responses and prevent lung and liver injuries associated with CoV2-SP-mediated cytokine storm.

Screening of cryptogamic secondary metabolites as putative inhibitors of SARS-CoV-2 main protease and ribosomal binding domain of spike glycoprotein by molecular docking and molecular dynamics approaches.

The unprecedented quick spreading of newly emerged SARS-CoV-2, the virus responsible for causing COVID-19 has put the whole world in vast crisis. Several prophylactic interventions are being performed to discover the effective anti-COVID-19 agent. Thus, the present study aims to identify the cryptogamic secondary metabolites (CSMs) as potent inhibitors of two major targets of SARS-Cov2, namely 3-chymotrypsin-like protease (3CLpro) and receptor-binding domain (RBD) of spike glycoprotein (SGP), by implementing a computational approach. Molecular docking was carried out on Autodock 4.2 software with the 3CLpro (PDB ID:6LU7) and RBD of SGP (PDB ID:6W41) of the virus. Lopinavir and Arbidol were taken as positive controls to compare the efficacy of randomly selected 53 CSMs. The drug-likeness and pharmacokinetics properties of all metabolites were accessed to discern the anti-COVID 19 activity acting well at the physiological conditions. The docking results predicted that Marchantin E and Zeorin would potentially block the catalytic site of 3CLpro with the interaction energy values of -8.42 kcal/mol and -9.04 kcal/mol, respectively. In addition, Usnic acid revealed its ability to combat the interaction of RBD of SGP to angiotensin-converting enzyme-2 in docking analysis. To certify the potent metabolites for both targets of SARS-CoV-2, MD analysis was performed for 100 ns. The results confirmed that Marchantin E could inhibit SARS-CoV-2 3CLpro and RBD of SGP as well as reveals excellent pharmacokinetic properties. The present study suggests that the identified CSMs could be quickly positioned for further experimental validation to propose promising inhibitors of SARS-CoV-2.