Table 1. In Vitro Activity of Amidines (1a–d), Hydroxyamidines (8a–d), Imidazolines (2c, 3c, and 14c), and Synthetic Intermediates (7a–d, 11c, 12c, 20, and 21).
|
T. b. brucei |
cytotoxicity |
rTAOg % inhibition at 40 μM | rTAO | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| EC50 (μM) |
CC50 (μM) |
IC50 (μM) | ||||||||
| cmpd | n | WTa | B48b | RFc | AQP1-3 KOd | RFc | HEKe | SIf | ||
| 1a | 3 | >100 | >100 | nd | >200 | 48% | >40j | |||
| 1b | 6 | 15.5 ± 0.6 | 28.0 ± 0.5 | 1.8 | 17.4 ± 0.9 | 1.1 | >200 | >12.9 | 12.5% | >40 |
| 1c | 12 | 3.3 ± 0.2 | 3.6 ± 0.1 | 1.1 | nd | 43.5 ± 5.4 | 13.2 | 39.3% | >40 | |
| 1d | 14 | 18.6 ± 1.1 | 28.9 ± 5.2 | 1.6 | nd | >200 | 10.7 | 31.4% | >40 | |
| 2c | 12 | 1.7 ± 0.3 | nd | 2.9 ± 0.4 | 1.7 | 67.2 ± 0.8h | 39.1 | 10.0%i | >10 | |
| 3c | 12 | 2.7 ± 0.4 | nd | 3.92 ± 0.03 | 1.4 | >100h | >36.5 | 46.3%i | 22.5 ± 0.3 | |
| 7a | 3 | 37.2 ± 3.4 | 50.8 ± 2.7 | 1.4 | nd | >200 | >5.3 | 28.8% | >40 | |
| 7b | 6 | 30.4 ± 0.4 | 27.7 ± 2.0 | 0.9 | 30.5 ± 0.7 | 1.0 | >200 | 6.6 | 96.2% | 1.5 ± 0.1 |
| 7c | 12 | 15.6 ± 0.7 | 15.9 ± 0.7 | 1.0 | nd | 57.1 ± 0.1 | 3.7 | 27.4% | >40 | |
| 7d | 14 | 14.8 ± 0.5 | 15.7 ± 0.5 | 1.1 | nd | 56.8 ± 0.2 | 3.8 | 89.7% | 16.4 ± 0.7 | |
| 8a | 3 | >100 | >100 | nd | >200 | 14.1 | >40 | |||
| 8b | 6 | 19.5 ± 1.0 | 36.0 ± 1.8 | 1.9 | 21 ± 1 | 1.1 | 76.8 ± 7.2 | 3.9 | –14.9% | >40 |
| 8c | 12 | 8.4 ± 1.1 | 9.1 ± 0.5 | 1.1 | 108.9 ± 1.6 | 13 | 44.8 | >40 | ||
| 8d | 14 | 29.0 ± 2.2 | 27.1 ± 2.4 | 0.9 | nd | >200 | 6.9 | –3.4% | >40 | |
| 11c | 12 | 9.5 ± 0.5 | nd | 10.2 ± 0.7 | 1.1 | >100h | >10.5 | 53.8%i | 30.0 ± 1.5 | |
| 12c | 12 | 20.3 ± 1.3 | nd | 29.6 ± 2.2 | 1.5 | >100h | >4.9 | nd | nd | |
| 14c | 12 | 10.4 ± 0.7 | nd | 15.7 ± 0.3 | 1.5 | >100h | >9.6 | nd | nd | |
| 20 | 15 | 5.8 ± 0.7 | nd | 8.2 ± 0.9 | 1.4 | >100h | >17.1 | 13.4%i | >10 | |
| 21 | 15 | >100 | nd | >100 | >100h | 30.0%i | >10 | |||
| diminazene | 0.095 ± 0.011 | 0.107 ± 0.019 | 1.1 | |||||||
| pentamidine | 0.004 ± 0.001 | 0.208 ± 0.021 | 49.5 | 0.046 ± 0.003 | 10.8 | |||||
| phenylarsine oxide | 0.9 ± 0.1 | |||||||||
| ascofuranone | 100% | |||||||||
a
Bloodstream form trypomastigotes of T. b. brucei strain 427 (n = 3).
b
T. b. brucei strain resistant to pentamidine (n = 3).
c
Resistance factor relative to WT.
d
T. brucei cell line from which all aquaporins were knocked out (n = 3).
e
Cytotoxicity on human embryonic kidney cells (n = 3).
f
Selectivity index (SI) = CC50/EC50 (WT).
g
Purified recombinant trypanosome alternative oxidase (ΔMTS-TAO)9 from T. b. brucei (n = 3); compound concentration = 40 μM.
h
n = 2.
i
Compound tested at 10 μM concentration.
j
No reliable IC50 could be obtained for inhibitors with less than 40% single-point inhibition as a sigmoidal curve could not be generated.