TABLE 4.

Molecular modeling of silibinin within the binding active site of SARS‐CoV‐2 RdRp compared to the native ligand

Compound	Moiety	Interaction	Amino acid residue
Silibinin	OH	H‐bond	U‐20
	OH	Metal bond	Mg‐1004
	CO	Metal bond	Mg‐1005
	OH	H‐bond	Asp‐618
	CH2OH	H‐bond	Ile‐548
	CH	Aromatic H‐bond hydrophobic bond	Asp‐618
	Phenyl ring	Hydrophobic bond	Lys‐545, Glu‐811, Asp‐618 and Ser‐814
	CH	Hydrophobic bond	Ile‐548, Lys‐551, ala‐547 and Asp‐760
	OCH3		Arg‐836
Native ligand	OH	H‐bond	U‐20
	Phosphate OH	Metal bond	Mg‐1004
	Phosphate OH	Metal bond	Mg‐1005
	Pyrrole	Pi‐cation	Arg‐555
	Phenyl	Hydrophobic bond	Arg‐555 and Asp‐761
	NH2	Hydrophobic bond	Thr‐687