Molecular docking of ethanol extracts of katuk leaf (Sauropus androgynus) on functional proteins of severe acute respiratory syndrome coronavirus 2

The COVID-19 pandemic has become a major health crisis globally. Alternative treatment approaches include using food sources rich in flavonoid compounds, such as the leaves of katuk plant (Sauropus androgynus). The purpose of this study was to analyze the characteristics of the flavonoid group present in active compounds of katuk leaves (Sauropus androgynus) and to study the mechanism underlying interactions (molecular docking) of these compounds with 3CLpro, Nsp1, Nsp3, RdRp, Nsp7_Nsp8 complex, and PLpro in SARS-CoV-2, and ACE2 in humans. In silico analysis was performed using Hex 8.0. software, which is primary tool of docking analysis. Interaction between the ligand and its receptors were analyzed using the software Discovery studio 4.1. The results of this study indicated that ABCD chains of 3CLpro had the highest bond energy with afzelin (-42.77 Kcal/mol), RdRp Nsp7_Nsp8 complex had the highest bond energy with trifolin (-310.87 Kcal/mol), PLpro had the highest bond energy with afzelin (-190.23 Kcal/mol), Nsp1 had the highest bond energy with afzelin (-286.89 Kcal/mol), Nsp3 had the highest bond energy with trifolin (-334.97 Kcal/mol), and ACE2 had the highest bond energy with trifolin (-307.96 Kcal/mol). Thus, on comparison with conventionally used drugs, the active flavonoid compounds in katuk leaves (Sauropus androgynus) showed specific affinity for 3CLpro, Nsp1, Nsp3, RdRp Nsp7_Nsp8 complex, and PLpro in SARS-CoV-2 and ACE2 in humans. Thus, katuk leaves a potential herbal candidates to derive new drugs or complementary medicines for COVID-19.