Table 3.

IC₅₀ ± SEM (μM) values of 16–28 on DU-145 (prostate cancer cells) and MCF-7 (mammary cancer cells) and nontumorigenic HEK-293 (embryonic kidney cells)^∗.

Compound no.	R	DU-145	MCF-7	Mean value	HEK-293
16	C3H7	77.8 ± 1.1	>100	-	51.1 ± 0.8
17	C5H11	>100	>100	-	77.4 ± 0.6
18	4-MeOPh	>100	>100	-	>100
19	2,5-(OMe)2Ph	>100	>100	-	>100
20	2-Furyl	36.5 ± 0.2	>100	-	35.1 ± 1.4
21	2-Thienyl	53.1 ± 5.0	>100	-	67.6 ± 2.5
22	CH3	12.3 ± 0.4	21.2 ± 0.3	16.7	28.6 ± 1.9
23	C3H7	22.5 ± 0.2	23.3 ± 0.5	22.9	21.5 ± 0.7
24	C5H11	54.6 ± 1.5	>100	-	58.4 ± 0.6
25	4-MeOPh	>100	73.5 ± 1.6	-	71.3 ± 1.2
26	2,5-(OMe)2Ph	28.7 ± 0.7	74.1 ± 2.4	51.4	53.3 ± 1.2
27	2-Furyl	13.2 ± 1.1	21.2 ± 1.4	17.2	11.2 ± 0.7
28	2-Thienyl	24.8 ± 0.3	33.1 ± 1.6	28.9	22.9 ± 0.7
DOX	-	0.70 ± 0.02	0.05 ± 0.003	-	4.27 ± 0.34

^∗Cells were incubated at 37°C for 48 h, with or without quinone derivatives. Afterwards, aliquots of cell suspensions were taken and the MTT test was performed, as described in Materials and Methods. Results are expressed as mean values ± SEM (n = 3). DOX = doxorubicin.