Table 2.
Cytotoxicity of doxorubicin against Caco-2 cells, either alone or in two-drug or three-drug combinations. The IC50 (μM) are presented as the mean ± SD. 0.3 < CI < 0.7 means synergism (+ + +), 0.7–0.85 moderate synergism (+ +). NR = not relevant. IB = isobologram. DRI = dose reduction indexes.
| Two-Drug Combinations | Three-Drug Combinations with Digitonin | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| IC50 of Dox | IB | DRI | CI | Interpretation | IC50 of Dox | IB | DRI | CI | Interpretation | |
| Doxorubicin alone | 4.97 ± 0.36 | 1.00 | NR | NR | 4.97 ± 0.36 | 1.00 | NR | NR | ||
| Dox + Capsaicin | ||||||||||
| 20 μM (IC10) | 2.14 ± 0.37 | syn | 2.33 | 0.56 | + + + | 1.35 ± 0.56 | syn | 3.68 | 0.30 | + + + |
| 34 μM (IC20) | 1.54 ± 0.51 | syn | 3.22 | 0.42 | + + + | 1.07 ± 0.34 | syn | 4.66 | 0.35 | + + + |
| 50 μM (IC30) | 1.26 ± 0.04 | syn | 3.94 | 0.57 | + + + | 0.59 ± 0.12 | syn | 8.39 | 0.41 | + + + |
| Dox + Piperine | ||||||||||
| 30 μM (IC10) | 2.05 ± 0.39 | syn | 2.42 | 0.80 | + + | 1.60 ± 0.65 | syn | 3.11 | 0.77 | + + |
| 50 μM (IC20) | 1.52 ± 0.10 | syn | 3.27 | 0.81 | + + | 1.02 ± 0.13 | syn | 4.88 | 0.72 | + + |
| 65 μM (IC30) | 0.90 ± 0.14 | syn | 5.52 | 0.76 | + + | 0.32 ± 0.09 | syn | 15.65 | 0.63 | + + + |