Gamma-Sitosterol for COVID-19

Abstract Background Coronavirus disease 2019 (COVID-19) is an infectious disease brought on by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a global treat in early 2020. Despite worldwide research proving different medications used to treat COVID-19, the infection still affects the human race; we need to continue researching the virus to protect humanity and reduce the complications that some medications might cause. This study focuses on finding another promising therapeutic compound against SARS-CoV-2. Twenty-four (24) bioactive compounds were selected from the following African plants' Adansonia digitata L, Aframomum melegueta K. Schum, Ageratum conyzoides (L.) L, and Boswellia dalzielii, and Remdesivir was used as the control medication. The PubChem web server acquired the 3D structures of bioactive compounds in the plant and the control medication. The SARS-CoV-2 main protease (Mpro) crystal structure was obtained using the Protein Data Bank (PDB). Using the SwissADME web server, the bioactive compounds' drug-likeness was assessed, and AutoDock was employed for the molecular docking with the Mpro. The Proteins Plus and Protein–Ligand Interaction Profiler web servers were used to analyse the docked complexes. Furthermore, the admetSAR website was utilized to predict the ligands' absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties. Results Based on the drug-likeness screening, Rutin violated more than one of the Lipinski rules of five, while Remdesivir violated two. Molecular docking analysis results indicated that Catechin, Epicatechin, Vitexin, Quercetin, Kaempferol, Gamma-Sitosterol, and Kaur-16-ene exhibited a stronger binding affinity with Mpro, with binding scores of − 7.1, − 7.1, − 8.0, − 7.3, − 7.2, − 6.8, and − 6.5 kcal/mol, respectively, compared to Remdesivir's binding score of − 6.3 kcal/mol. Consequently, binding scores of bioactive compounds suggest their potential biological activity against the SARS-CoV-2 main protease. Additionally, these bioactive compounds exhibited favourable ADMET properties. Vitexin also has a plasma protein binding below 90%, a promising medication distribution feature. Conclusions This study shows that Catechin, Epicatechin, Vitexin, Quercetin, Kaempferol, Gamma-Sitosterol, and Kaur-16-ene have better binding affinities with Mpro than Remdesivir. Molecular dynamics simulation in vitro and in vivo investigation is required to support this study.