Bioactive compounds screening of Rafflesia sp. and Sapria sp. (Family: Rafflesiaceae) as anti-SARS-CoV-2 via tetra inhibitors: An in silico research

Context: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread, causing a global pandemic with diverse symptoms and increased risk of mortality. Various symptoms and comorbidities contribute to a higher likelihood of death in patients. Additionally, existing antiviral drugs have shown incomplete efficacy. Rafflesia sp. and Sapria sp. are parasitic plants with potential medical applications as anti-SARS-CoV-2 agents. Aims: To evaluate the bioactive compounds derived from Rafflesia sp. and Sapria sp. as dual inhibitors against SARS-CoV-2. Methods: Ligand samples were obtained from the PubChem database. Target proteins essential for SARS-CoV-2 entry were obtained from the RCSB PDB. The antiviral potential of the bioactive compounds was evaluated using the Pass Online webserver. The bioactivity and inhibitory potential of selected ligands were analyzed using the SwissADME and Molinspiration web servers. In addition, a specific docking method was performed using PyRx software to determine binding activity and molecular interactions. Results: Computational analysis revealed that leucoanthocyanidin, ellagic acid, and catechin functioned as dual inhibitors, targeting angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), furin, and cathepsin L for antiviral activity. However, valrubicin and diminazene, serving as control drugs for ACE2 and furin, respectively, demonstrated the most effective results through this mechanism. Further studies are required to validate these findings. Conclusions: The combination of bioactive compounds derived from Rafflesia sp. and Sapria sp. shows potential antiviral activity through a dual inhibitor mechanism involving leucoanthocyanidin, ellagic acid, and catechin, which target SARS-CoV-2 proteins, namely ACE2, TMPRSS2, furin, and cathepsin L.