In Silico Study of Curcumin and Folic Acid as Potent Inhibitors of Human Transmembrane Protease Serine 2 in the Treatment of COVID-19

Abstract

Background. Human transmembrane protease 2 (TMPRSS2) protein is essential for priming spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in association with human angiotensin-converting enzyme 2 (ACE2) surface receptor to facilitate viral invasion into host human cell through ACE2 receptor. Impeding TMPRSS2 protein activity is currently a preferred choice of the treatment of coronavirus disease 2019 (COVID-19) which is caused by SARS-CoV-2. Curcumin and folic acid are potential candidates for inhibiting TMPRSS2. Objective. The present study aimed to demonstrate the inhibitory activities of curcumin and folic acid, along with known human serine protease inhibitors such as nafamostat and camostat, on TMPRSS2. Methods. Curcumin and folic acid, along with nafamostat and camostat, were docked on a modeled human TMPRSS2 protein 3D structure. Nafamostat and curcumin interactions with targeted TMPRSS2 protein were identical whereas camostat and folic acid displayed similar interactions. Results. The hydrogen bond (H-bond) energies of docked curcumin, folic acid, nafamostat, and camostat were −19.86 kJ/mol, −17.63 kJ/mol, −10.53 kJ/mol, and −14.41 kJ/mol, respectively. Higher H-bond energies could strengthen protein-ligand interactions. Our results showed binding site similarities between curcumin and nafamostat as well as folic acid and camostat. Conclusion. The current in silico simulation suggested that curcumin and folic acid displayed binding poses with TMPRSS2 which are similar to nafamostat and camostat. Therefore, curcumin and folic acid could emerge as potential drug candidates to control COVID-19.