Table 1.

IC₅₀ in vitro values of compound 22 and 24–27 on chloroquine (CQ) ^a sensible (D10) ^b and resistant (W2) ^b strains of P. falciparum; cytotoxicity on HMEC-1 cell line ^c and relevant selectivity index (SI) ^d; SI on NIH-3T3 cell line ^e.

Compounds	D10 IC50 (µM)	W2 IC50 (µM)	HMEC-1 IC50 (µM) c	SI d		SI e
				D10	W2	D10	W2
22	0.60 ± 0.21	0.70 ± 0.22	17.6 ± 1.4	29.3	25.2	147.7	126.5
24	1.63 ± 0.35	1.90 ± 1.05	8.51 ± 0.76	5.2	4.5	48.5	41.6
25	5.06 ± 1.68	5.02 ± 1.81	20.4 ± 1.60	4.0	4.1	11.0	11.1
26	1.21 ± 0.20	1.22 ± 0.24	17.9 ± 1.10	14.8	14.7	– f	– f
27	1.12 ± 0.40	0.81 ± 0.19	3.59 ± 0.72	3.2	4.4	32.6	45.0

^a CQ as positive control: D10 IC₅₀ (μM) = 0.04 ± 0.01; W2 IC₅₀ (μM) = 0.54 ± 0.28; not cytotoxic. ^b Data are the mean ± SD of three different experiments in duplicate. ^c Camptothecin as positive control: IC₅₀ (μM) = 0.018 ± 0.008. ^d SI = IC₅₀ HMEC-1/IC₅₀ P. falciparum strain. ^e SI = IC₅₀ NIH-3T3/IC₅₀ P. falciparum strain; cytotoxicity values on NIH-3T3 (µM) of compounds 22 and 24–27 are reported in a previous work [8]. ^f SI was not calculated since 26 is not active on NIH-3T3.