Table 3.
Interaction analysis of mutual mint infusions and mint infusions/rosmarinic acid combinations in DPPH and ABTS assays: IC50, CI, and DRI values of equal mass concentration infusions combinations at 50% inhibition dose level.
| Infusions Combination a | IC50 (μg/mL) b | r | CI c | SDA d | Combined Effect | DRI e | |
|---|---|---|---|---|---|---|---|
| DPPH | MPP:ML |
25.95 (28.45:25.39) |
0.98 (0.99:0.98) |
0.97 | ±0.02 | nearly additive | 2.19:1.96 |
| MPP:MVS |
33.38 (28.45:39.48) |
0.99 (0.99:0.99) |
1.01 | ±0.01 | nearly additive | 1.70:2.37 | |
| ML:MVS |
33.82 (25.39:39.48) |
0.97 (0.98:0.99) |
1.09 | ±0.02 | nearly additive | 1.50:2.33 | |
| MPP:ML:MVS |
31.68 (28.45:25.39:39.48) |
0.99 (0.99:0.98:0.99) |
1.05 | ±0.01 | nearly additive | 2.69:2.41:3.74 | |
| MPP:RA |
7.49 (28.45:2.28) |
0.98 (0.99:0.99) |
1.78 | ±0.03 | antagonism | 7.60:0.61 | |
| ML:RA |
11.01 (25.39:2.28) |
0.98 (0.98:0.99) |
2.63 | ±0.05 | antagonism | 4.61:0.41 | |
| MVS:RA |
5.33 (39.48:2.28) |
0.98 (0.99:0.99) |
1.24 | ±0.02 | moderate antagonism | 14.80:0.85 | |
| ABTS | MPP:ML |
21.83 (27.45:21.30) |
0.98 (0.97:0.98) |
0.91 | ±0.03 | nearly additive | 2.52:1.95 |
| MPP:MVS |
44.07 (27.45:40.81) |
0.98 (0.97:0.99) |
1.34 | ±0.04 | moderate antagonism | 1.25:1.85 | |
| ML:MVS |
29.21 (21.30:40.81) |
0.98 (0.97:0.99) |
1.04 | ±0.03 | nearly additive | 1.46:2.79 | |
| MPP:ML:MVS |
24.84 (27.45:21.30:40.81) |
0.96 (0.97:0.98:0.99) |
0.89 | ±0.03 | slight synergism | 3.32:2.57:4.93 | |
| MPP:RA |
3.64 (27.45:1.05) |
0.98 (0.97:0.99) |
1.80 | ±0.03 | antagonism | 15.09:0.58 | |
| ML:RA |
4.48 (21.30: 1.05) |
0.99 (0.98:0.99) |
2.24 | ±0.03 | antagonism | 9.51:0.47 | |
| MVS:RA |
3.78 (40.81:1.05) |
0.98 (0.99:0.99) |
1.85 | ±0.03 | antagonism | 21.60:0.56 |
a MPP—Mentha × piperita cv. ‘Perpeta’; ML—Mentha longifolia; MVS—Mentha × villosa cv. ‘Snežná’; RA—rosmarinic acid. b Median inhibitory activities IC50 (μg/mL) of the equal mass concentration infusions combinations and in bracket their single infusion/compound IC50 level. c CI—combination index, a quantitative measure based on the mass-action law of the degree of drug interaction in terms of synergism (CI < 1) and antagonism (CI > 1) for a given endpoint of the effect measurement. The combined effect is evaluated according to Chou (2006). 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 represents the order of magnitude (fold) of dose reduction that is allowed in combination for a given degree of effect as compared with the dose of each drug alone.