TABLE 2.

In vitro antimalarial activities of salinomycin, monensin, and nigericin against different stages of 3D7 P. falciparum gametocytes

Drug	Gametocyte stages	IC50 (nM) for incubation for (h)a:		SI for incubation for (h)b:		HMEC-1 IC50 (nM)a
		72	72 + 72	72	72 + 72
Salinomycin	II–III	29.7 ± 9.2c	14.5 ± 7.4d			157.5 ± 45.0
	IV–V	13.8 ± 1.4	6.3 ± 1.7	11.4	25.0
Monensin	II–III	4.6 ± 1.0	1.9 ± 1.3			169.6 ± 48.0
	IV–V	6.1 ± 1.1	5.7 ± 1.1	27.8	29.8
Nigericin	II–III	10.6 ± 4.0	2.7 ± 1.2			86.4 ± 31.0
	IV–V	9.3 ± 4.9	0.9 ± 0.4	9.3	96.0
DHA	II–III	>500	14.3 ± 8.7			3,094.8 ± 316.5
	IV–V	>500	156.3 ± 78.3	NAe	19.8
Epoxomicin	II–III	>100	12.1 ± 4.5			11.7 ± 3.1
	IV–V	>100	6.7 ± 1.9	NA	1.7

^aData are the means ± SD from at least two independent experiments in duplicate or triplicate.

^bSI, selectivity index, calculated as the IC₅₀ HMEC-1/IC₅₀ gametocytes at stage IV/V at the indicated incubation time.

^cP < 0.005, effect of salinomycin on stage II and III versus stage IV and V gametocytes at 72 h.

^dP < 0.005, effect of salinomycin on stage II and III versus stage IV and V gametocytes at 72 plus 72 h.

^eNA, not applicable.