. 2021 Feb 15;13(2):305. doi: 10.3390/v13020305

Table 1.

Intermolecular interactions observed for the best poses of docked natural products against reference compounds in the catalytic pocket of SARS-CoV-2 M^pro against the reference ligand.

S. no.	Compound	Docking Score (kcal/mol)	H-Bond	π-π/ * π- Cation Stacking	Hydrophobic	Polar	Negative	Positive	Glycine/ * Salt Bridge
1	Echinacoside	−14.17	Thr²⁵, Cys⁴⁴, Asn¹⁴², Gly¹⁴³, Gln¹⁸⁹, Thr¹⁹⁰	-	Leu²⁷, Val⁴², Cys⁴⁴, Met⁴⁹, Phe¹⁴⁰, Leu¹⁴¹, Cys¹⁴⁵, Met¹⁶⁵, Leu¹⁶⁷, Pro¹⁶⁸, Ala¹⁹¹	Thr²⁴, Thr²⁵, His⁴¹, Thr⁴⁵, Ser⁴⁶, Asn¹⁴², Ser¹⁴⁴, His¹⁶³, His¹⁶⁴, His¹⁷², Gln¹⁸⁹, Thr¹⁹⁰, Gln¹⁹²	Glu¹⁶⁶	Arg¹⁸⁸	Gly¹⁴³
2	Quercetagetin 7-Glucoside	−15.20	Cys⁴⁴(2), Leu¹⁴¹, Cys¹⁴⁵, Glu¹⁶⁶(2), Gln¹⁸⁹	* His⁴¹	Leu²⁷, Cys⁴⁴, Met⁴⁹, Phe¹⁴⁰, Leu¹⁴¹, Cys¹⁴⁵, Met¹⁶⁵, Leu¹⁶⁷, Pro¹⁶⁸	Thr²⁴, Thr²⁵, Thr²⁶, His⁴¹, Thr⁴⁵, Ser^46, Asn¹⁴², Ser¹⁴⁴, His¹⁶³, Gln¹⁸⁹	Glu¹⁶⁶	-	Gly¹⁴³
3	Levan N	−12.92	His⁴¹, Cys⁴⁴ Asn¹⁴², Gly¹⁴³, Gln¹⁸⁹(3)	-	Val⁴², Cys⁴⁴, Met⁴⁹, Leu¹⁴¹, Cys¹⁴⁵, Met¹⁶⁵	Thr²⁴, Thr²⁵, His⁴¹, Thr⁴⁵, Ser⁴⁶, Asn¹⁴², Ser¹⁴⁴, His¹⁶⁴, Gln¹⁸⁹	Glu¹⁶⁶	Arg¹⁸⁸	Gly¹⁴³
4	Inulin From Chicory	−11.72	Leu¹⁴¹, Gly¹⁴³, Glu¹⁶⁶ (2), Gln¹⁸⁹(2)	-	Met⁴⁹, Phe¹⁴⁰, Leu¹⁴¹, Cys¹⁴⁵, Met¹⁶⁵, Leu¹⁶⁷, Pro¹⁶⁸	His⁴¹, Asn¹⁴², Ser¹⁴⁴, His¹⁶³, His¹⁶⁴, Gln¹⁸⁹, Thr¹⁹⁰, Gln¹⁹²	Glu¹⁶⁶	Arg¹⁸⁸	Gly¹⁴³
5	1,3-Dicaffeoylquinic Acid	−10.01	Thr²⁶,Thr²⁵, Gly¹⁴³, Arg¹⁸⁸ (2)	-	Leu²⁷, Cys⁴⁴, Met⁴⁹, Cys¹⁴⁵, Met¹⁶⁵, Leu¹⁶⁷, Val¹⁸⁶	Thr²⁴, Thr²⁵, Thr²⁶, His⁴¹, Thr⁴⁵, Ser^46, Asn¹⁴², Ser¹⁴⁴, Gln¹⁸⁹, Thr¹⁹⁰, Gln¹⁹²	Glu¹⁶⁶, Asp¹⁸⁷	Arg¹⁸⁸	Gly¹⁴³/* His⁴¹
6	6-(ethylamino)pyridine-3-carbonitrile	−3.57	Arg¹⁸⁸	-	Met⁴⁹, Cys¹⁴⁵, Met¹⁶⁵, Leu¹⁶⁷, Pro¹⁶⁸	His⁴¹, His¹⁶⁴, Gln¹⁸⁹, Thr¹⁹⁰, Gln¹⁹²	Glu¹⁶⁶, Asp¹⁸⁷	Arg¹⁸⁸	Gly¹⁴³