Table 6.

The dock score of screened phytochemicals binding at the active site of the ACE2 and their important interactions with various amino acid residues.

Phytochemicals	B.E. (kcal/mole)	Important interactions at SGp-RBD docking site and catalytic sites (HIS345, HIS505 and ARG273)
Glycyrrhizinic acid	−9.5	Hydrogen bond: ARG273, HIS374, TYR515, ASN394; Pi-Alkyl: PHE40, HIS40; Carbon hydrogen bond: GLU402; VDW: ARG393, TYR385, GLU402, ASP350, ALA348, TRP349, ASP382, HIS505, PHE504.
Maslinic acid	−8.5	Hydrogen bond: PHE390, GLN388, ARG393, GLU37; Pi-Alkyl: VAL93, LYS26, PRO389; VDW: ASN33, ASP30, GLN96, THR92, ASN90.
Obacunone	−8.1	Hydrogen bond: ARG273; Pi-Sigma: PHE504; Pi-Pi T-shaped: PHE504; Pi-Alkyl: TRP271, PHE504; VDW: PHE274, GLU145, HIS505, ASN149, LEU503, TYR127, ASN508, SER128.
Epoxyazadiradione	−8.0	Alkyl/Pi-Alkyl: LYS26, PRO389; Pi-Sigma: HIS34; VDW: ASP30, ASN90, VAL93, GLN96, THR92, ASN33, GLU37.
Azadiradionolide	−8.0	Hydrogen bond: HIS345, HIS401, ASN394; Alkyl/Pi-Alkyl: HIS373, ALA348, HIS374; VDW: PHE40, TRP349, ASP350, THR347, GLU375, ARG514.
Ursolic acid	−7.4	Hydrogen bond: LYS26, ASN90, ARG393; Pi-Alkyl: VAL93, PRO389, HIS34; VDW: ASP30, THR92, GLN96, ASN33, ALA387, GLU37, PHE390.
Gedunin	−7.3	Hydrogen bond: HIS345; Alkyl/Pi-Alkyl: LUE370, PRO346, HIS374; Pi-Sigma: HIS374; Carbon hydrogen bond: PRO346; VDW: GLN442, ASP367, SER409, GLU406, GLU402, GLU375, THR371.