Table 1.

In vitro antimalarial activity and cytotoxicity of tricyclic guanidine derivatives

Compd No.	P. falciparum (D6 Clone) IC50 (μM)	P. falciparum (W2 Clone) IC50 (μM)	Cytotoxicity (Vero) IC50 (μM)	Compd No.	P. falciparum (D6 Clone) IC50 (μM)	P. falciparum (W2 Clone) IC50 (μM)	Cytotoxicity (Vero) IC50 (μM)
12a	6.49	7.22	NC	14l	2.25	2.82	NC
12b	1.98	2.70	NC	17b	3.04	3.53	NC
12c	1.48	1.43	6.71	17c	4.59	6.20	NC
12d	6.16	8.04	NC	17d	7.62	9.93	NC
12e	10.62	10.98	NC	17f	16.05	-	NC
12f	7.29	7.59	NC	17g	20.60	20.60	NC
12g	9.66	5.57	NC	17h	10.09	7.25	NC
12h	6.34	7.71	NC	17i	9.39	8.05	NC
12i	4.23	4.98	NC	17j	15.76	13.24	NC
12j	5.62	7.33	NC	17l	14.85	13.65	NC
12l	3.01	3.60	NC	20a	3.21	5.62	NC
14a	2.99	4.81	NC	20b	4.69	7.22	NC
14b	1.52	1.96	NC	20c	3.44	3.76	NC
14c	1.39	1.76	6.96	20d	9.24	12.45	NC
14d	6.20	8.26	NC	20e	19.27	19.27	NC
14e	6.27	7.66	NC	20f	6.54	9.45	NC
14f	1.69	2.18	NC	20g	17.14	19.24	NC
14g	14.13	-	NC	20h	2.41	3.02	NC
14h	1.25	1.64	NC	20i	5.78	7.71	NC
14i	1.37	2.26	NC	20l *	0.88	1.07	NC

IC₅₀ = sample concentration that causes 50% cell growth inhibition compared to vehicle control; NC = No cytotoxicity upto 4.76 μg/mL; “-” = Not active;

^*S.I.: selectivity index [TC50 (Vero)/IC₅₀ (P. falciparum)] > 17;

Chloroquine: IC₅₀ = 0.052 μM (D6 clone); IC₅₀ = 0.46 μM, (W2 clone). Artemisinin: IC₅₀ = 0.018 μM (D6 clone); IC₅₀ = 0.015 μM (W2 clone).