Table 2. MIC values of the four derivatives against the clinical staphylococcal isolates.
| Strains | Derivativesa | The range of MICb (μM) | MIC50c (μM) | MIC90c (μM) |
|---|---|---|---|---|
| MRSE (44) | H2-38 | 0.75–12.5 | 3.13 | 6.25 |
| H2-39 | 3.125–12.5 | 3.13 | 6.25 | |
| H2-74 | 3.125–12.5 | 6.25 | 12.5 | |
| H2-81 | 0.75–6.25 | 3.13 | 6.25 | |
| MSSE (24) | H2-38 | 0.75–6.25 | 3.13 | 6.25 |
| H2-39 | 1.5–12.5 | 3.13 | 6.25 | |
| H2-74 | 3.13–25 | 6.25 | 12.5 | |
| H2-81 | 0.75–12.5 | 3.13 | 6.25 | |
| MRSA (55) | H2-38 | 0.75–12.5 | 6.25 | 12.5 |
| H2-39 | 1.5–25 | 6.25 | 12.5 | |
| H2-74 | 1.5–25 | 6.25 | 12.5 | |
| H2-81 | 0.75–12.5 | 3.13 | 6.25 | |
| MSSA (40) | H2-38 | 0.75–12.5 | 3.13 | 6.25 |
| H2-39 | 1.5–12.5 | 3.13 | 6.25 | |
| H2-74 | 3.125–100 | 6.25 | 12.5 | |
| H2-81 | 0.75–12.5 | 3.13 | 6.25 |
a
Stock solutions of the compounds were prepared in 0.1% DMSO.
b
MIC represents the minimal inhibitory concentration of the derivatives against the test strains as determined by broth micro-dilution testing on a microtiter plate according to the standards of the American Clinical and Laboratory Standards Institute.
c
The MIC50 is the concentration below which 50% of the clinical isolate MIC values lie, and MIC90 is the concentration below which 90% of the isolate MIC values lie.