Table 2.

Active Flavonoids against Coronavirus SARS-CoV-2.

S.No	Virus	Flavonoid	Experiment model	IC50/Binding Energies	Inhibition target
1	Coronavirus. SARS-CoV-2	Epigallocatechin Gallate (EGCG)	In-vitro	IC50 = 7.58 μg/ml	Main protease-MPro
2		Theaflavin	In-vitro	IC50 = 8.44 μg/ml	Main protease-MPro
3		Myricitrin	In-silico	Binding energy = −8.9 kcal/mol	Main protease-MPro
4		Taiwanhomoflavone A	In-silico	Binding energy = −9.6 kcal/mol	RNA-dependent RNA-Polymerase (RdRp) and Human Angiotensin Converting Enzyme-2 (hACE-2)
5		Rutin	In-silico	Binding energy = −8.2072 kcal/mol	Main protease-MPro
6		Fisetin	In-silico	binding affinity score= −8.5 kcal/mol	spike protein
7		Biochanin A	In-silico	Docking energy score= −78.41	Protease domain-ACE-2 & RBD-Spike protein
8		Silymarin	In-silico	Docking energy score= −121.28 kcal/mol	Protease domain-ACE-2 & RBD-Spike protein
9		Quercetin	In-silico	binding affinity score= −8.5 kcal/mol	spike protein
				binding affinity score= −9.2 kcal/mol	Main protease-MPro
10		Narcissin	In-silico	binding affinity score= −8.2530 and	Main protease-MPro
11		kaempferol-3-O-rutinoside	In-silico	binding affinity score= −8.1203 kcal/mol	Main protease-MPro
12		Naringin	In-silico	binding energy = −9.8 kcal/mol	Spike protein

(IC₅₀) The half-maximal inhibitory concentration is a measure of a substance's ability to inhibit biological activity. Binding affinity, energy scores are the energy values when a ligand bind to a protein in Molecular Docking studies, Or The binding free energy is defined as the sum of the ligand's inter-molecular interactions with the protein and the ligand's internal steric energy.