Table 5.
The top 25 ranked chemicals for inhibition of deiodinase type 3 (DIO3), based on absolute IC50, with activity across the deiodinases (DIOs) indicating which chemicals produced 50% inhibition or greater in each of the deiodinase assays in single-point screening.
| DIO3 |
Across DIOs |
||||||
|---|---|---|---|---|---|---|---|
| Rank | Chemical | CASRN | Max Tested Conc., μM |
% Inhibition at Max Conc.a |
IC20 (μM) |
IC50 (μM) |
≥ 50% Inhibition |
| 1 | Nordihydroguaiaretic acid | 500-38-9 | 200 | 97 | 0.01 | 0.1 | DIO 1, 2, 3 |
| 2 | Chlorothalonil | 1897-45-6 | 200 | 76 | 0.1 | 0.5 | DIO 1, 2, 3 |
| 3 | Pentachloropyridine | 2176-62-7 | 200 | 98 | 0.2 | 1.0 | DIO 2, 3 |
| 4 | Fipronil | 120068-37-3 | 200 | 101 | 0.3 | 1.2 | DIO 1, 2, 3 |
| 5 | Quinoxyfen | 124495-18-7 | 200 | 88 | 0.2 | 1.3 | DIO 2, 3 |
| 6 | Hexadecyltrimethylammonium bromide | 57-09-0 | 200 | 97 | 1.0 | 1.6 | DIO 1, 2, 3 |
| 7 | AVE6324 | NOCAS_47377 | 200 | 86 | 0.4 | 1.8 | DIO 1, 2, 3 |
| 8 | Fluazinam | 79622-59-6 | 180 | 101 | 0.4 | 2.0 | DIO 1, 2, 3 |
| 9 | Triflumizole | 68694-11-1 | 200 | 102 | 0.5 | 2.3 | DIO 1, 2, 3 |
| 10 | Ergocalciferol | 50-14-6 | 200 | 95 | 0.5 | 2.6 | DIO 1, 2, 3 |
| 11 | Chlorhexidine diacetate | 56-95-1 | 200 | 103 | 1.3 | 2.6 | DIO 1, 2, 3 |
| 12 | 6-Hydroxy-2-naphthyl disulfide | 6088-51-3 | 200 | 102 | 0.6 | 3.1 | DIO 1, 2, 3 |
| 13 | Octadecyl sulfate sodium salt | 1120-04-3 | 200 | 93 | 1.7 | 3.3 | DIO 1, 2, 3 |
| 14 | Hexachlorocyclopentadiene | 77-47-4 | 200 | 99 | 0.7 | 3.3 | DIO 1, 2, 3 |
| 15 | Didecyldimethylammonium chloride | 7173-51-5 | 200 | 100 | 2.8 | 3.3 | DIO 1, 2, 3 |
| 16 | 4,5-Dichloro-3H-1,2-dithiol-3-one | 1192-52-5 | 200 | 103 | 0.7 | 3.3 | DIO 1, 2, 3 |
| 17 | Tributyltetradecylphosphonium chloride | 81741-28-8 | 200 | 81 | 2.8 | 3.3 | DIO 1, 2, 3 |
| 18 | 1,2-Benzenedicarboxaldehyde | 643-79-8 | 200 | 93 | 0.7 | 3.5 | DIO 1, 2, 3 |
| 19 | Methyltrioctylammonium chloride | 5137-55-3 | 200 | 89 | 3.2 | 3.8 | DIO 1, 2, 3 |
| 20 | 2-(8-Heptadecenyl)-2-imidazoline-1-ethanol | 95-38-5 | 200 | 101 | 3.3 | 3.9 | DIO 1, 2, 3 |
| 21 | Bisphenol A diglycidyl ether | 1675-54-3 | 200 | 94 | 0.9 | 4.1 | DIO 1, 2, 3 |
| 22 | Ascorbyl palmitate | 137-66-6 | 200 | 98 | 1.2 | 4.2 | DIO 1, 2, 3 |
| 23 | Kepone | 143-50-0 | 200 | 100 | 2.2 | 4.4 | DIO 1, 2, 3 |
| 24 | 2-Benzylideneoctanal | 101-86-0 | 200 | 84 | 1.1 | 4.7 | DIO 2, 3 |
| 25 | SSR69071 | 344930-95-6 | 50 | 90 | 1.6 | 5.1 | DIO 2, 3 |
a
Median of three replicates at maximum concentration of chemical in concentration-response testing; inhibition in single-point results differed by 11% or less except quinoxyfen, which produced 49.4% inhibition, and 2-benzylideneoctanal which produced 65.0% inhibition.