Abstract:
A new dicoumarin, jusan coumarin, (1), has been isolated from Artemisia glauca aerial
parts. The chemical structure of jusan coumarin was estimated, by 1D, 2D NMR as well as HR-Ms
spectroscopic methods, to be 7-hydroxy-6-methoxy-3-[(2-oxo-2H-chromen-6-yl)oxy]-2H-chromen-2-
one. As the first time to be introduced in nature, its potential against SARS-CoV-2 has been estimated
using various in silico methods. Molecular similarity and fingerprints experiments have been utilized
for 1 against nine co-crystallized ligands of COVID-19 vital proteins. The results declared a great
similarity between Jusan Coumarin and X77, the ligand of COVID-19 main protease (PDB ID: 6W63),
Mpro. To authenticate the obtained outputs, a DFT experiment was achieved to confirm the similarity
of X77 and 1. Consequently, 1 was docked against Mpro. The results clarified that 1 bonded in a correct
way inside Mpro active site, with a binding energy of −18.45 kcal/mol. Furthermore, the ADMET and
toxicity profiles of 1 were evaluated and showed the safety of 1 and its likeness to be a drug. Finally,
to confirm the binding and understand the thermodynamic characters between 1 and Mpro, several
molecular dynamics (MD) simulations studies have been administered. Additionally, the known
coumarin derivative, 7-isopentenyloxycoumarin (2), has been isolated as well as β-sitosterol (3).
