Table 1.

In vitro anti-proliferative activity of the 2,3-dehydrosilybins against prostate cancer cell lines

Comp. No	R	IC50 (μM)a			IC50 (silybin)/IC50 (derivative)
		LNCaPb	DU145c	PC-3d	LNCaP	DU145	PC-3
silybin	–	43.73 ± 10.90	93.34 ± 13.76	72.65 ± 3.15	1	1	1
14	methyl	4.74 ± 1.04	27.44 ± 10.15	8.89 ± 2.21	9	3	8
15	ethyl	>100	>100	>100	<1	<1	<1
16	propyl	9.95 ± 1.85	13.41 ± 2.91	12.94 ± 0.74	4	7	6
17	butyl	8.62 ± 1.11	14.01 ± 0.83	11.39 ± 0.93	5	7	6
18	pentyl	6.83 ± 2.07	17.66 ± 3.04	12.69 ± 1.39	6	5	6
19	hexyl	10.78 ± 2.20	35.37 ± 10.84	20.83 ± 6.20	4	3	3
20	heptyl	6.95 ± 1.28	20.53 ± 2.21	16.67 ± 0.79	6	5	4
21	methyl	4.57 ± 0.42	103.76 ± 7.73	29.3 ± 3.69	10	1	2
22	ethyl	33.63 ± 0.95	>100	>100	1	<1	<1
23	propyl	3.52 ± 1.02	10.00 ± 2.06	19.49 ± 2.48	12	9	4
24	butyl	3.26 ± 0.33	22.12 ± 3.81	49.94 ± 3.89	13	4	1
25	pentyl	6.47 ± 0.67	30.66 ± 3.28	39.95 ± 5.39	7	3	2
26	hexyl	4.84 ± 0.86	20.54 ± 5.06	20.21 ± 2.45	9	5	4
27	heptyl	2.35 ± 0.29	9.70 ± 1.90	5.88 ± 1.19	19	10	12
29	methyl	6.55 ± 0.49	6.95 ± 0.48	5.84 ± 1.78	7	13	12
30	ethyl	2.62 ± 1.35	4.61 ± 1.54	7.08 ± 1.68	17	20	10
31	propyl	3.17 ± 0.15	3.95 ± 0.59	7.62 ± 1.45	14	24	10
32	butyl	3.35 ± 0.47	4.22 ± 1.07	7.46 ± 1.93	13	22	10
33	pentyl	2.34 ± 0.87	4.30 ± 0.22	7.92 ± 1.46	19	22	9
34	hexyl	2.53 ± 1.34	4.31 ± 0.32	5.99 ± 0.64	17	22	12
35	heptyl	2.24 ± 0.21	3.23 ± 0.77	4.61 ± 0.64	20	29	16

^aIC₅₀ is the drug concentration effective in inhibiting 50% of the cell viability measured by the WST-1 cell proliferation Assay after 3 days exposure.

^bHuman androgen-sensitive prostate cancer cell line

^cHuman androgen-insensitive prostate cancer cell line

^dHuman androgen-insensitive prostate cancer cell line