Table 1.

Inhibition of ABCG2-mediated efflux and cytotoxicity. The inhibition of ABCG2-mediated mitoxantrone efflux was assayed in HEK293-ABCG2 cells.

Compound	IC50 (µM) ± SDa	IMAX (%) ± SDb	IG50 (µM) ± SDc	TRd
5a	0.25 ± 0.01	72.55 ± 3.72	> 100	> 393.60
5b	0.45 ± 0.10	112.80 ± 3.67	12.58 ± 5.12	28.10
5c	0.65 ± 0.03	60.05 ± 4.04	36.50 ± 20.08	56.41
5d	2.71 ± 0.14	68.50 ± 0.68	26.70 ± 5.52	9.85
5e	0.15 ± 0.08	36.88 ± 1.16	66.50 ± 7.78	453.11
5f.	0.18 ± 0.02	48.39 ± 0.80	27.35 ± 7.57	153.24
5g	0.44 ± 0.03	65.23 ± 0.94	25.95 ± 14.35	58.79
5h	0.42 ± 0.07	69.62 ± 1.14	24.25 ± 3.32	57.21
5i	0.07 ± 0.02	62.83 ± 0.48	19.80 ± 3.39	293.66
5j	0.48 ± 0.08	85.57 ± 2.59	15.65 ± 7.28	32.86
5k	0.92 ± 0.10	115.70 ± 2.36	21.10 ± 2.55	22.85
5l	0.24 ± 0.03	82.35 ± 3.44	14.25 ± 0.07	59.72
5m	0.19 ± 0.07	87.42 ± 2.46	12.60 ± 7.22	66.23
5n	4.09 ± 0.56	133.18 ± 3.35	21.50 ± 5.09	5.26
6a	0.21 ± 0.03	62.65 ± 2.30	> 100	> 469.65
6c	0.48 ± 0.10	90.51 ± 8.07	39.05 ± 26.94	81.35
6d	0.19 ± 0.04	84.79 ± 2.51	33.30 ± 13.86	176.12
6e	0.20 ± 0.04	66.80 ± 1.79	41.50 ± 33.52	212.38
p4he,19	0.23 ± 0.02	100.00 ± 21.00	> 100	> 435.00
p4je,19	0.21 ± 0.07	106.00 ± 21.00	27.20 ± 0.70	130.00
p4ke,19	0.31 ± 0.09	78.00 ± 14.00	12.70 ± 3.10	41.00
p5he,20	0.15 ± 0.01	85.00 ± 11.00	54.00 ± 14.00	360.00

^aThe affinity of inhibitor interaction was expressed as IC₅₀ values (compound concentrations giving a half-maximal inhibition).

^bThe maximal inhibition percentage (I_MAX) was determined by IC₅₀ fitted curves.

^cThe cytotoxicity was expressed as IG₅₀ values (compound concentrations giving a half-maximal cell viability).

^dThe therapeutic ratio (TR) corresponds to the ratio between IG₅₀ and IC₅₀ values.

^eExperimental data of compounds p4h, p4j, p4k and p5h correspond to those previously published.