Table 2.

The binding energy, types of interaction and amino acids involved in the interaction of S protein of SARS-CoV2 with curcumin and catechin.

Protein–Ligand	Binding affinity (kcal/mol)	Types of interaction	Interacting AA Name; AA No;
S Protein–curcumin	− 7.9	Van der waals	Leu546, Gly548, Phe541, Asn856, Leu997, Ser967, Asp571, Ala570, Val976, Thr572
		Conventional hydrogen bond	Asp979, Thr547, Arg1000, Ser975
		Carbon–hydrogen bond	Thr573, Asn978, Cys743
		Pi–donor hydrogen bond	Thr573, Asn978, Cys743
		Pi–Sigma	Leu966
S Protein–catechin	− 10.5	Van der waals	Gln314, Glu309, Lys310, Gly311, Ile664, Lys733, Leu861, Asp950, Gly769, Ala766, Lys304, Thr761
		Conventional hydrogen bond	Tyr313, Thr768, Asn764, Thr302, Gln954, Asp775
		Carbon–hydrogen bond	Ile312
		Pi–sigma	Thr768, Val772, Leu303
		Pi–cation	Arg765
		Pi–alkyl	Ile312, Pro665, Arg765