Biological activity of quinone-indole derivatives 122–124.

Compd.	Activity	Ref.
122	SiIHa cells: IC50 = 3.2 μM	177
	CaLo cells: IC50 = 2.69 μM
	C33-A cells: IC50 = 0.0034 μM
123	A578 cells: IC50 = 5 nM	178
Shikonin	A578 cells: IC50 = 0.46 μM	178
124	MCF-7 cells: IC50 = 11.33 μM	181
	HepG2 cells: IC50 = 10.14 μM
	MG-63 cells: IC50 = 13.85 μM
Naphthoquinone	MCF-7 cells: IC50 = 16.92 μM	181
	HepG2 cells: IC50 = 15.89 μM
	MG-63 cells: IC50 > 25 μM