Table 3.
Assessment of the antioxidant activity of comfrey (S. officinale) roots collected from different European regions and stored for 1–6 months.
| Storage Period (Months) |
DPPH | ABTS | CUPRAC | FRAP | MCA | PDA |
|---|---|---|---|---|---|---|
| mg TE/g d.w. Root | mg EDTAE/g d.w. Root | mmol TE/g d.w. Root | ||||
| Sample FS | ||||||
| M1 | 5.36 ± 0.17 a | 34.95 ± 0.14 a | 13.25 ± 0.13 a | 13.85 ± 0.76 a | 2.80 ± 0.07 a | 0.25 ± 0.03 a |
| M2 | 16.60 ± 0.07 b | 37.26 ± 0.74 b | 39.80 ± 0.55 b | 40.91 ± 1.27 b | 3.19 ± 0.12 b | 0.36 ±0.00 b |
| M3 | 26.59 ± 0.27 c | 100.72 ± 4.21 c | 52.05 ± 0.29 c | 55.38 ± 1.12 c | 4.52 ± 0.22 c | 0.56 ± 0.02 c |
| M6 | 16.55 ± 0.17 b | 71.49 ± 0.94 d | 32.39 ± 0.68 d | 34.14 ± 0.80 d | 2.62 ± 0.17 a | 0.27 ± 0.01 a |
| Sample IS | ||||||
| M1 | 24.05 ± 0.36 d | 118.87 ± 2.03 e | 42.48 ± 0.30 e | 42.68 ± 0.04 b | 7.61 ± 0.35 d | 0.48 ± 0.03 d |
| M2 | 28.21 ± 0.70 e | 123.03 ± 7.51 f | 50.21 ± 1.98 c | 52.14 ± 0.32 e | 6.73 ± 0.30 e | 0.69 ± 0.02 e |
| M3 | 26.92 ± 0.58 c | 130.95 ± 0.72 g | 60.74 ± 1.37 f | 64.93 ± 1.02 f | 6.34 ± 0.35 e,f | 0.59 ± 0.02 c |
| M6 | 24.13 ± 0.42 d | 122.14 ± 1.61 f | 52.67 ± 0.71 c | 52.63 ± 0.85 c | 5.90 ± 0.46 f | 0.61 ± 0.01 c |
| Sample NT | ||||||
| M1 | 38.15 ± 0.32 f | 157.76 ± 5.54 h | 80.13 ± 0.87 g | 90.67 ± 1.74 g | 2.59 ± 0.18 a | 0.79 ± 0.02 f |
| M2 | 26.78 ± 0.21 c | 129.12 ± 0.68 g | 62.28 ± 1.72 f | 70.62 ± 0.23 h | 3.69 ± 0.24 g | 0.53 ± 0.01 g |
| M3 | 38.49 ± 0.41 f | 173.25 ± 1.43 i | 76.36 ± 0.97 h | 86.91 ± 1.10 f | 3.37 ± 0.32 g | 0.85 ± 0.03 h |
| M6 | 21.28 ± 0.34 g | 83.81 ± 1.73 j | 39.19 ± 0.97 b | 48.02 ± 0.63 i | 1.91 ± 0.08 h | 0.48 ± 0.01 d |
| Sample CH | ||||||
| M1 | 8.19 ± 0.26 h | 53.45 ± 0.21 k | 20.27 ± 0.20 i | 21.18 ± 1.16 j | 4.28 ± 0.10 i | 0.39 ± 0.04 b |
| M2 | 16.48 ± 0.44 b | 92.71 ± 1.02 l | 29.39 ± 0.91 d | 38.58 ± 0.17 k | 4.65 ± 0.22 c | 0.44 ± 0.03 d |
| M3 | 29.25 ± 0.23 e | 96.37 ± 2.70 m | 46.85 ± 0.48 j | 51.93 ± 1.23 c | 7.43 ± 0.06 d | 0.50 ± 0.01 g |
| M6 | 2.19 ± 0.45 i | 10.02 ± 2.41 n | 8.66 ± 0.07 i | 8.24 ± 0.10 l | 0.54 ± 0.04 j | 0.15 ± 0.02 i |
| Sample PL | ||||||
| M1 | 25.20 ± 1.22 c,d | 114.09 ± 0.18 e | 41.75 ± 0.69 e | 45.78 ± 0.49 i | 5.38 ± 0.66 f | 0.72 ± 0.01 e |
| M2 | 17.99 ± 0.24 b | 74.08 ± 1.70 d | 29.89 ± 0.07 d | 36.75 ± 0.12 d,k | 3.77 ± 0.42 g | 0.58 ± 0.03 c |
| M3 | 24.04 ± 0.89 d | 106.90 ± 5.13 c | 42.61 ± 0.89 e | 51.48 ± 0.40 c | 4.15 ± 0.64 c | 0.81 ± 0.04 f |
| M6 | 27.44 ± 0.40 c | 128.22 ± 2.62 g | 43.17 ± 1.14 e | 56.00 ± 0.46 c | 5.20 ± 0.31 f | 0.79 ± 0.02 f |
Data are presented as mean ± standard deviation (SD) of three determinations; values sharing different superscripts within columns are significantly different at p < 0.05 (Tukey’s test); ABTS, 2,2′-azino-bis(3-ethylbenzothiazoline) 6-sulfonic acid; CUPRAC, cupric ion reducing antioxidant capacity; DPPH, 1,1-diphenyl-2-picrylhydrazyl; EDTAE, EDTA equivalents; FRAP, ferric ion reducing antioxidant power; MCA, metal chelating activity; PDA, phosphomolybdenum activity; TE, trolox equivalents.