Table 5.
Interaction analysis of Lycopus spp. infusions, luteolin-7-O-glucuronide, and rosmarinic acid.
| Method | Sample Combination | IC50 (μg/mL) a | r b | CI c | SDA d | Combined Effect | DRI e |
|---|---|---|---|---|---|---|---|
| ABTS | LeuB:RA | 2.32 | 0.97 | 0.66 | ±0.01 | Synergism | 7.19:1.25 |
| LeuB:LGlr | 6.64 | 0.98 | 0.83 | ±0.01 | Moderate synergism | 2.64:2.22 | |
| LGlr:RA | 2.74 | 0.98 | 0.81 | ±0.01 | Moderate synergism | 5.38:1.61 | |
| LeuB:RA:LGlr | 3.39 | 0.99 | 0.80 | ±0.01 | Moderate synergism | 7.74:1.95:6.52 | |
| DPPH | Lex:RA | 2.75 | 0.96 | 0.93 | ±0.01 | Nearly additive effect | 6.03:1.31 |
| Lex:LGlr | 2.96 | 0.97 | 0.63 | ±0.01 | Synergism | 5.60:2.22 | |
| LGlr:RA | 1.90 | 0.96 | 0.81 | ±0.03 | Moderate synergism | 3.46:1.90 | |
| Lex:RA:LGlr | 2.57 | 0.99 | 0.84 | ±0.01 | Moderate synergism | 9.70:2.12:3.85 | |
| DCFH-DA | Lex:RA | 0.73 | 0.98 | 0.74 | ±0.01 | Moderate synergism | 6.00:1.74 |
| Lex:LGlr | 0.98 | 0.98 | 0.75 | ±0.02 | Moderate synergism | 4.44:1.91 | |
| LGlr:RA | 0.54 | 0.96 | 0.72 | ±0.02 | Moderate synergism | 3.45:2.32 | |
| Lex:RA:LGlr | 0.58 | 0.99 | 0.61 | ±0.01 | Synergism | 11.16:3.23:4.80 |
a IC50 (μg/mL) of the equal mass concentration infusion combinations; b r—linear correlation coefficient of the median effect plot; c CI—combination index, a quantitative determination of drug interactions based on the mass action law, where CI < 1, = 1, and > 1 indicate synergism, additive effect, and antagonism, respectively (the combined effect is evaluated according to Chou [24]); d SDA—sequential deletion analysis, iterative sequential deletion of one dose (or concentration) of a drug at a time for repetitive CI calculations; e DRI—dose reduction index shows the extent that the dose of each drug in a synergistic combination can be reduced at a given effect level compared with the doses of each sample alone; LeuA—L. europaeus A; LeuB—L. europaeus B; LeuC—L. europaeus C; Lex—L. exaltatus; LGlr—luteolin-7-O-glucuronide; RA—rosmarinic acid.