Table 2.

Chemical Structure, Growth Inhibition of MDA-MB-231 Breast Tumor Cell Line, and PDE5 Inhibitory Activity of Tetrahydro-β-carboline-hydantoins (11–30)

compd	stereochemistry	X,Y	R	% growth inhibition at 10 μMa	growth inhibition IC50 (μM) and CI at p < 0.05b	% PDE 5 inhibition at 10 μMa	PDE 5 inhibition IC50 (μM) and CI at p < 0.05b
11	5R,11aR	2,4-dichloro	–C2H5	39	ND	95	0.010 (0.005–0.024)
12	5S,11aR	2,4-dichloro	–C2H5	54	ND	90	0.090 (0.08–0.11)
13	5S,11aS	2,4-dichloro	–C2H5	29	ND	85	0.85 (0.67–1.07)
14	5R,11aS	2,4-dichloro	–C2H5	68	5.37 (4.71–6.11)	95	0.007 (0.004–0.009)
15	5R,11aR	3,4-dichloro	–C2H5	50	ND	95	0.15 (0.10–0.24)
16	5S,11aR	3,4-dichloro	–C2H5	60	ND	78	2.86 (2.40–3.40)
17	5S,11aS	3,4-dichloro	–C2H5	78	4.78 (1.03–12.12)	60	8.75 (6.90–10.64)
18	5R,11aS	3,4-dichloro	–C2H5	18	ND	90	0.30 (0.23–0.40)
19	5R,11aR	2,6-dichloro	–C2H5	55	ND	18	ND
20	5S,11aS	2,6-dichloro	–C2H5	52	ND	37	ND
21	5R,11aR	2,4-dichloro	–C-(CH3)3	68	2.26 (1.52–3.33)	80	0.59 (0.41–0.85)
22	5S,11aR	2,4-dichloro	–C-(CH3)3	65	0.64 (0.50–0.80)	73	1.48 (1.19–1.84)
23	5S,11aS	2,4-dichloro	–C-(CH3)3	22	ND	75	4.14 (3.27–5.23)
24	5R,11aS	2,4-dichloro	–C-(CH3)3	69	1.26 (1.04–1.53)	95	0.070 (0.06–0.08)
25	5R,11aR	3,4-dichloro	–C-(CH3)3	99	3.25 (1.46–4.0)	82	1.87 (1.53–2.28)
26	5S,11aR	3,4-dichloro	–C-(CH3)3	58	ND	65	6.38 (5.01–8.12)
27	5S,11aS	3,4-dichloro	–C-(CH3)3	70	1.43 (0.94–3.79)	80	2.31 (1.79–2.97)
28	5R,11aS	3,4-dichloro	–C-(CH3)3	60	ND	88	0.012 (0.005–0.024)
29	5R,11aR	2,6-dichloro	–C-(CH3)3	38	ND	52	ND
30	5S,11aS	2,6-dichloro	–C-(CH3)3	15	ND	25	ND

^aCalculated from duplicate values.

^bCalculated from at least 8 concentrations, each with quadruple replicates, p < 0.05.