Table 1.

Effective concentration (EC) in µM of 25 di-substituted urea compounds against T. cruzi epimastigotes and LLC-MK₂ cells.

Compound	T. cruzi epimastigotesa		LLC-MK2b EC50 (μM)	Selectivity Indexc (SI)
	EC50 (μM)	EC90 (μM)
3p	1.3d	4.4d	7.7 ± 3.7	5.9
6a	1.7 ± 0.1	7.5 ± 0.5	13.7 ± 8.7	8.0
I-17	3.4 ± 1.3	5.7 ± 1.5	32.4 ± 14.7	9.5
3e	2.3d	2.8d	6.6 ± 3.6	1.4
6b	2.5 ± 0.4	4.6 ± 0.1	2.5 ± 0.4	1.0
I-18	3 ± 0.7	6.6 ± 1.8	12.3 ± 8.8	4.1
3 g	3.3 ± 0.1	8.4 ± 2.4	7 ± 4.7	2.1
3r	3.5 ± 0.1	6 ± 0.9	8.6 ± 1.2	2.4
3q	3.7 ± 2.5	8.7 ± 1.0	1.2 ± 1.3	0.7
3 f	5.4 ± 0.2	16.8 ± 5.5	N.T.f	N.T.
3o	5.5 ± 0.4	7.3 ± 0.8	N.T.	N.T.
3 m	5.9 ± 0.3	7.7 ± 0.1	N.T.	N.T.
3i	6.3 ± 0.5	12.1 ± 1.7	N.T.	N.T.
I-m6	6.5 ± 0.2	10.4 ± 0.8	N.T.	N.T.
3a	7.7 ± 0.5	9.9 ± 0.3	N.T.	N.T.
3c	7.7 ± 0.4	9.7 ± 0.4	N.T.	N.T.
3 h	8.2 ± 0.1	13.5 ± 4.5	N.T.	N.T.
3b	>10g	>10	N.T.	N.T.
3n	>10	>10	N.T.	N.T.
3d	>10	>10	N.T.	N.T.
3j	>10	>10	N.T.	N.T.
3k	>10	>10	N.T.	N.T.
3 l	>10	>10	N.T.	N.T.
3t	>10	>10	N.T.	N.T.
NCPdCPU	>10	>10	N.T.	N.T.
BZNe	211 ± 3.0	960 ± 25.0	N.T.	N.T.

^aEpimastigotes of T. cruzi were incubated for 3 days in the presence of different concentrations of each compound in triplicate experiments, each value  determined in duplicate measurements. The concentration that inhibited 50% (EC₅₀) or 90% (EC₉₀) of multiplication was determined by using the Alamar Blue assay as described in Methods.

^bLLC-MK₂ were plated and after 24 h, incubated with the different concentrations of the indicated compounds. After two more days, cell viability was measured with Alamar Blue assay as described in Methods and the results used to determine the (EC₅₀).

^cTI = Ratio between T. cruzi EC₅₀ and LLC-MK₂ EC₅₀.

^dThese values correspond to a single experiment.

^eBZN = Benznidazole.

^fN.T. = not tested.

^g>10 = without apparent effect at 10 µM.