. 2007 Oct 15;52(1):98–109. doi: 10.1128/AAC.00609-07

TABLE 3.

Interaction of artemisinin and two novel endoperoxides with thapsigargin

Starting concn (μM) of thapsigargin^a	Assays with artemisinin				Assays with compound 3a				Assays with compound 3c
	Artemisinin concn (μM)	Apparent IC₅₀ (μM)		SFIC	Starting concn (μM) of compound 3a	Apparent IC₅₀ (μM)		SFIC	Starting concn (μM) of compound 3c	Apparent IC₅₀ (μM)		SFIC
	Artemisinin concn (μM)	Artemisinin	Thapsigargin	SFIC	Starting concn (μM) of compound 3a	Compound 3a	Thapsigargin	SFIC	Starting concn (μM) of compound 3c	Compound 3c	Thapsigargin	SFIC
2.5	0.04	0.010	0.31	1.04	1.6	0.14	0.22	0.8	0.6	0.10	0.42	0.97
5.0	0.02	0.0072	0.83	0.83	0.8	0.14	0.93	0.8	0.3	0.068	1.12	0.77
10.0	0.01	0.0054	2.33	0.85	0.4	0.079	2.0	0.71	0.15	0.048	3.02	0.84

Twofold dilutions of the drugs combined in a fixed ratio were added to P. falciparum parasites (strain D10). The apparent IC₅₀ values for each of the drugs were estimated and used to calculate the SFIC values. The results represent the mean values for an experiment performed in duplicate. The IC₅₀ values for the individual drugs determined for this data set were 7.4 μM for thapsigargin, 0.010 μM for artemisinin, 0.18 μM for compound 3a, and 0.11 μM for compound 3c.