Isolation, structural elucidation and molecular docking studies against SARS-CoV-2 main protease of new stigmastane-type steroidal glucosides isolated from the whole plants of Vernonia gratiosa

Abstract

Phytochemical investigation of the whole plants of Vernonia gratiosa Hance. led in the isolation and identification of two new stigmastane-type steroidal glucosides (1–2), namely vernogratiosides A (1), and B (2). Their chemical structures were fully elucidated based on 1 D/2D NMR spectroscopic, HR-ESI-MS data analyses, and by producing derivatives by chemical reactions. The binding potential of the isolated compounds to replicase protein − main protease of SARS-CoV-2 were examined using the molecular docking simulations. Our results show that the isolated steroidal glucosides (1–2) bind to the substrate‐binding site of SARS-CoV-2 main protease with binding affinities of −7.2 and −7.6 kcal/mol, respectively, as well as binding abilities equivalent to N3 inhibitor that has already been reported (–7.5 kcal/mol).

Graphical Abstract

Keywords:

• Molecular docking
• SARS-CoV-2 main protease
• stigmastane-type steroidal glucoside
• Vernonia gratiosa

Disclosure statement

All of the authors declare no competing financial interest.

Additional information

Funding

This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOST ED) under grant number 104.01-2020.11 and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2019R1A6A1A03031807).