Table 1.

Alkaloids

Compound name	Plant species	Level of activity	Predicted or known target of virus	Mode of action or other activities	References
Berberine (1)	Coptidis sp.	IC50 = 2.0 ± 0.5 μM	MHV-A59		[22]
Cepharanthine (2)	Stephania cepharantha	IC50 = 0.83 ± 0.07 μM	HCoV-OC43		[23]
Fangchinoline (3)	Stephania tetrandra	IC50 = 1.01 ± 0.07 μM	HCoV-OC43	Inhibit viral replication and expression of viral S and N protein	[23]
Indigodole B (4)	Strobilanthes cusia	IC50 = 2.09 μM	HCoV-NL63		[24]
Jubanine H (5)	Zizyphus jujuba	EC50 = 4.49 ± 0.67 μM	PEDV		[17]
Nummularine B (6)	Zizyphus jujuba	EC50 = 6.17 ± 0.50 μM	PEDV, CoV		[17]
Tetrandrine (7)	Stephania tetrandra	IC50 = 0.33 ± 0.33 μM	HCoV-OC43		[23]
Tryptanthrin (8)	Strobilanthes cusia	IC50 = 0.06 μM	HCoV-NL63	Blocking viral RNA genome synthesis and papain-like protease 2 activity	[24]