Table 2. . IC50 values (μM) of compounds 1–3 determined for a normal (NF54) and chloroquine-resistant (Dd2) Plasmodium falciparum strain, Chinese hamster ovary cells and HDAC6.
| Cmpd | NF54 | Dd2 | CHO | SI‡ | RI§ | HDAC6 |
|---|---|---|---|---|---|---|
| 1a | 37.5 | – | – | – | – | 0.015 |
| 1b | 14.0 | – | – | – | – | – |
| 1c | 2.2 | 3.1 | 105.2 | 48 | 1.4 | 0.022 |
| 1d | 23.2 | – | – | – | – | – |
| 1e | 10.8 | – | – | – | – | 0.002 |
| 1f | 21.0 | – | – | – | – | 2.0 |
| 1g | 15.8 | – | – | – | – | 0.004 |
| 1h | 32.7 | – | – | – | – | 1.3 |
| 1i | 0.11 | 0.43 | 109.0 | 991 | 3.9 | 0.003 |
| 1j | 1.28 | 1.3 | >282 | >217 | 1.0 | 0.014 |
| 1k | 0.40 | 0.80 | >269 | >673 | 2.0 | 0.009 |
| 1l | 0.92 | 0.66 | >281 | >305 | 0.7 | 0.008 |
| 1m | 1.07 | 1.55 | >267 | >250 | 1.7 | 0.016 |
| 1n | 1.48 | 2.18 | >295 | >199 | 1.5 | – |
| 1o | 1.32 | 1.44 | 48.1 | 36 | 1.1 | – |
| 1p | 5.45 | – | – | – | – | – |
| 1q | 7.84 | – | – | – | – | – |
| 1r | 8.13 | – | – | – | – | – |
| 1s | 12.2 | – | – | – | – | – |
| 1t | 9.80 | – | – | – | – | – |
| 1u | 11.9 | – | – | – | – | – |
| 2a | 1.60 | 2.13 | 12.7 | 8 | 1.3 | 0.014 |
| 2b | 32.4 | – | – | – | – | – |
| 2c | 1.02 | 2.4 | 31.0 | 30 | 2.4 | 0.037 |
| 2d | 17.8 | – | – | – | – | – |
| 2e | 5.07 | – | – | – | – | – |
| 2f | 5.75 | – | – | – | – | – |
| 2g | 1.30 | 1.58 | 46.1 | 35 | 1.2 | 0.064 |
| 2h | 8.45 | – | – | – | – | – |
| 2i | 3.34 | 1.14 | 31.2 | 9 | 0.3 | – |
| 2j | 5.02 | – | – | – | – | – |
| 2k | 36.8 | – | – | – | – | – |
| 3a | 1.59 | >2.7 | 103.9 | 65 | – | 0.036 |
| 3b | >2.48 | >2.48 | 41.4 | – | – | 0.650 |
| 3c | 1.53 | >2.29 | 61.5 | 40 | – | 0.200 |
| 3d | 0.36 | 0.94 | 107.6 | 303 | 2.6 | 0.008 |
| 3e | 0.47 | 0.44 | 35.4 | 75 | 0.9 | 0.068 |
| 3f | 0.87 | 0.70 | 56.8 | 65 | 0.8 | 0.011 |
| 3g | 1.25 | >2.60 | 172.9 | 138 | – | 0.006 |
| 3h | >2.61 | >2.61 | 87.0 | – | – | 0.033 |
| 3i | >2.48 | 1.57 | 50.9 | – | – | 0.160 |
| 3j | >2.61 | >2.61 | 61.7 | – | – | 0.092 |
Bold: IC50-value of the hydroxamic acid lower than 1 μM against both P. falciparum strains. ‘–’ is not determined.
‡SI (selectivity index) = IC50 (CHO)/IC50 (NF54).
§RI (resistance index) = IC50 (Dd2)/IC50 (NF54).
Chloroquine IC50-NF54 = 0.01 μM, IC50-Dd2 = 0.175 μM; Artesunate IC50-NF54 < 0.01 μM, IC50-Dd2 = 0.016 μM; Emetine IC50-CHO = 0.112 μM.
CHO: Chinese hamster ovary; RI: Resistance index; SI: Selectivity index.