Table 2. Inhibitors of tritryp trypanothione synthetase (TryS) identified in this work and their biological activity.
| Compound | Structurea | TcTryS | LiTryS | TbTryS | T. b. Brucei EC50 (μM)b | L. infantum EC50 (μM)c | SId |
|---|---|---|---|---|---|---|---|
| MOL2008 | AI (P) | 40.5 ± 5.9%; (1.00) | 0.15 ± 0.06 μM e; (0.99); 0.35 ± 0.03 f | 59.0 ± 6.0%; (0.97) | 4.3 ± 0.7 | 12.6 ± 1.6 | 2.4 (0.8) |
| FS-554 | AI (P) | 55.5 ± 3.8%; (1.02) | 0.35 ± 0.05 μM e; (0.99); 0.36 ± 0.04 f | ~75 μM; (0.94 at 300 μM) | ND | 112.3 ± 1.1 g | ND (0.6) |
| ZEA10 | APPDA | 32.3 ± 4.0% | 32.1 ± 6.4% | 48.7 ± 2.8%; (1.41) | 0.28 ± 0.08 | ND | >4 |
| ZEA35 | APPDA | 61.3 ± 7.6%; (1.01) | 13.8 ± 9.7% | 24.3 ± 6.1% | ND | ND | ND |
| ZEA40 | APPDA | 52.2 ± 1.4%; (1.02) | 15.3 ± 8.3% | 25.3 ± 5.2% | ND | ND | ND |
| ZEA41 | APPDA | 65.4 ± 1.5%; (0.99) | 13.6 ± 3.4% | 20.9 ± 4.4% | ND | ND | ND |
| EAP1-47 | BDA | 53.5 ± 1.3%; (1.48) | 47.8 ± 1.8%; (1.34) | 51.1 ± 4.2%; (1.49) | 0.20 ± 0.02 | ND | 15 |
| EAP1-63 | BDA | 30.8 ± 3.8% | 25.9 ± 9.3% | 47.5 ± 2.8%; (1.30) | 0.090 ± 0.007 | ND | 124 |
| EAP1-67 | BDA | 23.8 ± 6.6%; (1.34) | 51.5 ± 5.3%; (1.35) | 42.4 ± 1.6%; (1.33) | ND | ND | ND |
| APC1-87 | BDA | 26.6 ± 4.1% | 56.7 ± 7.9%; (1.26) | 37.9 ± 4.0% | ND | ND | ND |
| APC1-89 | BDA | 25.6 ± 1.4% | 23.4 ± 2.7%; (1.32) | 50.9 ± 1.5%; (1.31) | 0.061 ± 0.001 | ND | 164 |
| APC1-99 | BDA | 33.4 ± 4.1% | 39.1 ± 3.4% | 48.9 ± 1.7%; (1.05) | 0.015 ± 0.001 | ND | 67 |
| APC1-101 | BDA | 17.0 ± 2.1%; (1.40) | 26.3 ± 10.1%; (1.36) | 61.2 ± 1.8%; (1.33) | 0.28 ± 0.09 | ND | 10 |
| APC1-111 | BDA | 28.9 ± 4.1%; (1.57) | 49.6 ± 5.7%; (1.51) | 55.6 ± 3.2%; (1.52) | 0.040 ± 0.001 | ND | 67 |
| J18 | BZ | 63.5 ± 1.5%; (1.00) | 41.3 ± 3.6%; (1.00) | 7.3 ± 5.9% | ND | ND | ND |
In vitro and in vivo (cell) activity profile of most promising TryS inhibitors. Enzyme inhibition is expressed as % TryS inhibition ± 2σn-1 and IC50 values in μM concentration ± 2σn-1. For compounds affecting BIOMOL GREEN signal, the interference factor used to correct TryS activity is provided in brackets (see S1 Text). All values reported stem from at least duplicates. ND, not determined.
a the chemical scaffolds are: AI (P), 4,5-dihydroazepino[4,5-b]indol-2(1H,3H,6H)-one derivatives, paullone derivatives; APPDA, 6-arylpyrido[2,3-d]pyrimidine-2,7-diamine derivatives; BDA, N,N'-bis(3,4-substituted-benzyl) diamine derivatives; BZ, benzofuroxan derivatives.
b Cytotoxicity against bloodstream Trypanosoma brucei brucei expressed as effective concentration 50: EC50.
c Cytotoxicity against Leishmania infantum promastigotes is expressed as effective concentration 50: EC50.
d Selectivity index calculated as the ratio: EC50 for murine macrophages (cell line J774) vs. EC50 for T. b. brucei or EC50 for L. infantum (value in brackets).
e IC50 value calculated from 3 independent experiments and expressed as mean ± 2 S.D.
f Slope from IC50 plots calculated from 3 independent experiments and expressed as mean ± 2 S.D.
g EC50 value reported by [20]