Table 2.

Binding affinities of baicalin and baicalein with SARS-CoV-2 3CLpro determined by ITC and MRMS, and the calculated ligand efficiency (LE) of two compounds.

Compounds	Kd ITC (µM)	ΔG ITC (kJ/mol)	LE ITC (kcal/mol)	Kd MRMS (µM)	IC50 (µM)
Baicalin	11.50 ± 1.89	−28.20 ± 0.42	0.21	12.73 ± 0.81	6.41 ± 0.95
Baicalein	4.03 ± 0.37	−30.78 ± 0.24	0.37	1.40 ± 0.10	0.94 ± 0.20