Table 1.
Effect of SL-ester chain length on minimum inhibitory concentrations (MICs).
| SLs | MIC (µM) | TI | ||||
|---|---|---|---|---|---|---|
| B. cereus 1 | B. subtilis 1 | S. aureus 1 | L. innocua 2 | E. coli 1 | ||
| Lactonic SL 3 | 25 | 12 | 25 | 50 | >200 | 2 |
| SL-methyl ester | 50 | 50 | 200 | 100 | >200 | >8 |
| SL-ethyl ester | 50 | 50 | 200 | 50 | >200 | 6 |
| SL-propyl ester | 25 | 25 | 100 | 25 | >200 | 16 |
| SL-butyl ester | 12 | 12 | 100 | 12 | >200 | 33 |
| SL-pentyl ester | 12 | >200 | >200 | 12 | >200 | 17 |
| SL-hexyl ester | >200 | >200 | >200 | >200 | >200 | - |
| SL-octyl ester | >200 | >200 | >200 | >200 | >200 | - |
| Streptomycin | 12 | 12 | 3 | 24 | 12 | - |
1 Incubation time: 16 h. 2 Incubation time: 30 h. 3 Natural component used to prepare SL esters. Therapeutic index (TI) was calculated as EC50 macrophage/MICB. Cereus. EC50 was determined as concentration causing 50% killing of macrophage after 16 h.