Table 1.
Change of phenolic content and antioxidant activity of pomegranate leaf infusion by spectrophotometric assays.
| Spectrophotometric Analysis 1 | Storage Time (Hours) 2 | Degradation |
p-Value (2–8 h) |
p-Value (0–24 h) |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 2 | 4 | 6 | 8 | 24 | |||||
| Phenolic content | Total phenols (mg GA g−1 DW) |
133.47 ± 3.40 a | 132.02 ± 5.01 a | 132.49 ± 2.35 a | 132.34 ± 0.46 a | 129.67 ± 4.50 a | 131.40 ± 1.60 a | 1.55% | 0.43 | 0.80 |
|
Ortho-diphenols (mg GA g−1 DW) |
244.25 ± 3.59 a | 238.63 ± 2.32 a | 240.01 ± 2.14 a | 237.24 ± 3.25 a | 240.42 ± 0.63 a | 239.91 ± 3.57 a | 1.78% | 0.70 | 0.12 | |
| Flavonoids (mg RU g−1 DW) |
55.84 ± 0.45 a | 54.86 ± 0.73 ab | 54.46 ± 0.54 abc | 53.67 ± 0.78 bc | 53.81 ± 0.22 bc | 53.30 ± 0.11 c | 4.54% | 0.61 | 0.00 | |
| Tannins (mg EC g−1 DW) |
124.20 ± 3.67 a | 110.60 ± 3.50 b | 109.35 ± 1.11 bc | 107.37 ± 2.90 bc | 105.68 ± 3.42 bc | 102.15 ± 1.24 c | 17.75% | 0.27 | 0.00 | |
| Antioxidant capacity (mmol Trolox g−1 DW) | ABTS scavenging | 1.80 ± 0.00 a | 1.72 ± 0.02 b | 1.71 ± 0.01 b | 1.69 ± 0.04 b | 1.68 ± 0.04 b | 1.66 ± 0.03 b | 7.93% | 0.63 | 0.00 |
| DPPH scavenging | 1.69 ± 0.01 a | 1.63 ± 0.04 ab | 1.60 ± 0.03 ab | 1.54 ± 0.03 b | 1.56 ± 0.03 b | 1.59 ± 0.06 b | 5.92% | 0.14 | 0.00 | |
| FRAP assay | 2.23 ± 0.01 a | 2.21 ± 0.01 a | 2.09 ± 0.01 b | 2.06 ± 0.01 bc | 2.03 ± 0.02 c | 2.03 ± 0.03 c | 9.29% | 0.00 | 0.00 | |
1 Abbreviations are as follows: GA, gallic acid; RU, rutin; EC, epicatechin; DW, dry weight; ABTS: 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt; DPPH: 2,2-diphenyl-1-picrylhidrazyl; and FRAP: ferric reducing antioxidant power. 2 Values are presented as the mean ± SD (n = 3) for each phenolic group and each antioxidant activity assay. Mean values followed by different superscript lowercase letters report significant differences between different storage times, according to Tukey’s multiple range test.