Table II.
The combination index values at actual experimental points for the combination of fisetin and arsenic trioxide in K562 cells.
| Drug combination
|
CI | fa | Interaction type | |
|---|---|---|---|---|
| FIS (µM) | ATO (µM) | |||
| 10 | 0.5 | 33.91 | 0.001 | Very potent antagonism |
| 20 | 1.0 | 1.13 | 0.102 | Slight antagonism |
| 30 | 1.5 | 0.68 | 0.245 | Synergism |
| 40 | 2.0 | 0.78 | 0.279 | Moderate synergism |
| 50 | 2.5 | 0.76 | 0.341 | Moderate synergism |
The combination index (CI) values were calculated according to the method of Chou-Talalay using CompuSyn software. CI <1 represents synergism, with CI of 0.1-0.3 indicating strong synergism, 0.3-0.7 indicating synergism, CI of 0.7-0.85 indicating moderate synergism, CI of 0.85-0.90 indicating slight synergism, CI of 0.90-1.10 indicating a nearly additive effect, CI of 1.10-1.20 indicating a slight antagonism, CI of 1.20-1.45 indicating a moderate antagonism, CI of 1.45-3.3 indicating antagonism, CI of 3.3-10 indicating strong antagonism, and CI above 10 indicating very potent antagonism. fa, fraction affected by dose; FIS, fisetin; ATO, arsenic trioxide.