TABLE 1.
Antitrypanosomal activities of tested fluoroquinolones
| Compound | Structure
|
EC50a
|
|||||
|---|---|---|---|---|---|---|---|
| Nucleus | R1 | R7 (nucleus A) or R8 (nucleus B or C) | X8 (nucleus A) or X10 (nucleus B or C) | Against T. brucei (μM) | Against L1210 cells (μM) | Ratiob | |
| Norfloxacin | A | CH3CH2- | CH | 70 | >100 | >1.4 | |
| Enoxacin | A | CH3CH2- | N | 51 | 60 | 1.2 | |
| Ciprofloxacin | A | c-C3H5 | CH | 52 | 73 | 1.4 | |
| Pefloxacin | A | CH3CH2- | CH | 97 | 68 | 0.7 | |
| Fleroxacin | A | CH2FCH2- | CF | >100 | >100 | 1 | |
| Ofloxacin | B | O | >100 | >100 | 1 | ||
| KB-5246 | C | O | 1.7 | 3.7 | 2.2 | ||
| KB-5290 | C | N-CH3 | 3.7 | 9.5 | 2.6 | ||
| KB-6600 | C | N-CH3 | 11 | 29 | 2.6 | ||
| KB-6625 | C | N-CH3 | 14 | 21 | 1.5 | ||
a
Average of two determinations. EC50 of >100 μM indicate that curves could not be adequately fitted due to limited solubility of the fluoroquinolone. Differences between the average and individual EC50 never exceeded 30%. The r2 value obtained for each concentration-cell killing curve always exceeded 0.96 and averaged 0.99 (standard deviation, ±0.01); the coefficient of variation for quadruplicate determinations in the assay was always less than 18% and averaged 4.6% (≤18%).
b
Ratio of the EC50 with L1210 cells to that with T. brucei.