Table 7.
Individual phenolics for the walnut bark across the six selected cultivars.
| Compound | Bark Phenolic Content per Cultivar (mg/100 g Dry Weight) | |||||
|---|---|---|---|---|---|---|
| ‘Fernor’ | ‘Fernette’ | ‘Franquette’ | ‘Sava’ | ‘Krka’ | ‘Rubina’ | |
| Naphthoquinones | ||||||
| Juglone | 251.0 ± 31.2 ac | 185.8 ± 8.6 ab | 281.2 ± 16.6 bc | 169.4 ± 10.2 a | 219.4 ± 24.1 ac | 299.8 ± 35.6 c |
| Hydrojuglone | 72.8 ± 2.2 bc | 89.9 ± 9.6 c | 50.7 ± 7.2 ab | 65.9 ± 5.5 bc | 21.3 ± 2.4 a | 66.9 ± 9.8 bc |
| Hydrojuglone β-D-glucopyranoside | 239.8 ± 13.0 a | 366.1 ± 18.7 b | 342.3 ± 17.8 ab | 285.5 ± 26.2 ab | 255.1 ± 11.9 ab | 523.4 ± 52.7 c |
| Hydrojuglone rutinoside | 47.6 ± 4.8 ab | 30.9 ± 3.1 a | 40.6 ± 5.5 a | 34.9 ± 2.8 a | 45.1 ± 3.8 ab | 60.9 ± 2.1 b |
| Hydrojuglone derivative 2 | 16.6 ± 5.1 a | 10.5 ± 4.7 a | 156.3 ± 21.1 b | 32.0 ± 9.2 a | 143.9 ± 9.4 b | 143.3 ± 22.0 b |
| Hydrojuglone derivative 4 | 1258.0 ± 73.5 c | 877.8 ± 53.9 b | 639.1 ± 83.0 ab | 471.6 ± 35.5 a | 417.4 ± 17.0 a | 535.2 ± 78.9 a |
| Hydrojuglone derivative pentoside 1 | 566.3 ± 25.2 b | 757.7 ± 34.4 c | 401.4 ± 14.1 a | 699.1 ± 35.5 bc | 363.2 ± 21.9 a | 394.7 ± 42.7 a |
| Hydrojuglone derivative pentoside 2 | 6579.7 ± 402.1 b | 7608.0 ± 301.1 b | 4768.3 ± 337.3 a | 7189.0 ± 266.6 b | 4672.8 ± 174.5 a | 4954.1 ± 494.4 a |
| Hydrojuglone derivative pentoside 3 | 605.9 ± 24.3 bc | 743.9 ± 32.8 c | 487.3 ± 24.5 ab | 681.9 ± 36.8 c | 427.7 ± 16.0 a | 460.3 ± 49.8 ab |
| Hydrojuglone derivative rhamnoside | 2015.2 ± 110.6 a | 2332.2 ± 103.3 a | 2172.8 ± 157.9 a | 2039.4 ± 75.6 a | 2222.2 ± 123.3 a | 2230.2 ± 193.9 a |
| Dihydroxytetralone hexoside | 43.4 ± 3.0 a | 54.0 ± 4.7 a | 48.8 ± 2.8 a | 47.2 ± 6.8 a | 37.7 ± 5.7 a | 49.6 ± 3.5 a |
| Hydroxybenzoic acids | ||||||
| Gallic acid derivative 2 | 80.0 ± 5.3 ab | 89.9 ± 5.3 ab | 106.7 ± 4.9 b | 92.5 ± 7.0 ab | 71.8 ± 3.5 a | 93.0 ± 8.9 ab |
| Gallic acid derivative 3 | 29.7 ± 3.1 bc | 31.1 ± 1.5 c | 15.6 ± 0.8 a | 35.2 ± 3.6 cd | 16.8 ± 2.3 ab | 44.1 ± 4.3 d |
| Ellagic acid derivative | 145.6 ± 12.6 b | 153.9 ± 8.9 b | 155.8 ± 9.7 b | 93.2 ± 9.4 a | 111.0 ± 7.1 ab | 123.0 ± 13.6 ab |
| Flavanols | ||||||
| Procyanidin dimer 2 | 219.8 ± 18.8 a | 277.1 ± 20.2 a | 301.3 ± 25.6 a | 335.3 ± 24.5 a | 288.7 ± 14.6 a | 333.2 ± 45.3 a |
| Procyanidin dimer derivative 2 | 200.9 ± 10.5 ab | 248.2 ± 21.8 b | 213.0 ± 17.1 ab | 245.4 ± 17.8 b | 149.8 ± 7.8 a | 178.4 ± 25.6 ab |
| (+)Catechin | 528.2 ± 56.6 a | 557.9 ± 40.9 a | 675.5 ± 42.0 a | 708.7 ± 49.5 a | 748.8 ± 53.0 a | 797.2 ± 103.9 a |
| Flavones | ||||||
| Santin | 14.4 ± 2.0 b | 6.3 ± 0.4 a | 7.7 ± 0.6 a | 10.6 ± 2.2 ab | 6.6 ± 0.3 a | 7.8 ± 0.1 a |
| 5,7-Dihydroxy-3,4-dimetoxyflavone | 2.2 ± 0.6 ab | 0.9 ± 0.1 a | 4.3 ± 0.3 b | 4.4 ± 0.9 b | 2.4 ± 0.2 ab | 3.6 ± 0.5 b |
| Flavonols | ||||||
| Myricetin pentoside | 21.4 ± 1.3 a | 26.9 ± 1.5 a | 29.4 ± 1.0 a | 29.1 ± 2.7 a | 23.1 ± 3.2 a | 23.1 ± 3.2 a |
| Myricetin-3-rhamnoside | 129.4 ± 9.0 a | 156.3 ± 8.2 a | 162.7 ± 3.9 a | 152.1 ± 12.5 a | 121.0 ± 6.8 a | 133.4 ± 12.9 a |
| Quercetin-3-galactoside | 210.4 ± 10.7 a | 261.9 ± 19.1 ab | 248.4 ± 9.7 ab | 322.1 ± 28.4 b | 224.9 ± 6.5 a | 228.0 ± 25.0 a |
| Quercetin-3-glucoside | 141.0 ± 6.2 ab | 159.0 ± 5.1 ab | 124.3 ± 11.1 ab | 165.4 ± 9.2 b | 115.7 ± 4.2 a | 133.3 ± 17.6 ab |
| Quercetin-3-arabinopyranoside | 69.0 ± 2.3 a | 93.5 ± 3.6 ab | 91.5 ± 6.1 ab | 100.1 ± 8.4 b | 74.1 ± 1.8 ab | 78.1 ± 9.7 ab |
| Quercetin-3-arabinofuranoside | 69.6 ± 1.9 ab | 100.4 ± 7.4 bc | 96.7 ± 7.9 ac | 123.4 ± 6.7 c | 64.9 ± 2.4 a | 92.4 ± 14.0 ac |
| Quercetin-3-rhamnoside | 223.8 ± 11.5 ab | 320.1 ± 13.3 bc | 255.5 ± 33.4 ab | 373.9 ± 19.0 c | 171.7 ± 5.5 a | 315.1 ± 47.4 bc |
| Quercetin galoyll hexoside | 82.7 ± 5.8 ab | 97.3 ± 4.9 ab | 82.6 ± 7.0 ab | 101.6 ± 6.5 b | 69.5 ± 3.0 a | 76.9 ± 10.0 ab |
| Kaempferol-7-hexoside 1 | 150.5 ± 9.7 bc | 237.1 ± 8.6 d | 113.0 ± 18.3 ab | 195.3 ± 11.7 cd | 63.5 ± 6.3 a | 107.7 ± 23.5 ab |
| Kaempferol-7-hexoside 2 | 30.2 ± 1.3 b | 42.2 ± 1.5 c | 32.2 ± 3.6 bc | 26.6 ± 2.4 b | 14.8 ± 2.3 a | 34.1 ± 2.7 bc |
| Total naphthoquinones | 11696.3 ± 654.3 bc | 13056.9 ± 527.9 c | 9388.8 ± 596.2 ab | 11716.0 ± 488.3 bc | 8825.9 ± 339.7 a | 9718.4 ± 919.8 ab |
| Total hydroxycinnamic acids | nd | nd | nd | nd | Nd | nd |
| Total hydroxybenzoic acids | 255.3 ± 15.9 a | 274.9 ± 15.4 a | 278.2 ± 14.1 a | 220.8 ± 19.8 a | 199.6 ± 11.4 a | 260.2 ± 25.9 a |
| Total flavanols | 948.9 ± 84.2 a | 1083.3 ± 78.6 a | 1189.8 ± 81.3 a | 1289.3 ± 88.6 a | 1187.3 ± 72.3 a | 1308.7 ± 174.5 a |
| Total flavones | 16.6 ± 2.0 c | 7.2 ± 0.4 a | 12.0 ± 0.8 ac | 15.0 ± 2.9 bc | 9.0 ± 0.5 ab | 11.4 ± 0.6 ac |
| Total flavanones | nd | nd | nd | nd | Nd | nd |
| Total flavonols | 1128.0 ± 17.3 ab | 1494.5 ± 63.9 bc | 1236.2 ± 97.9 ac | 1589.5 ± 89.0 c | 943.2 ± 16.5 a | 1222.2 ± 160.8 ac |
| Total phenolics content (summation; relevant stadnards) x | 14045.2 ± 757.1 ac | 15916.8 ± 676.0 c | 12104.9 ± 774.8 ab | 14830.6 ± 673.2 bc | 11165.1 ± 422.7 a | 12520.9 ± 1270.9 ac |
| Total phenolics content (total extracts; mg gallic acid equivalents/100 g dry weight) y | 1956.2 ± 77.6 a | 2236.4 ± 251.1 a | 2544.4 ± 251.3 a | 1898.2 ± 121.7 a | 1979.3 ± 38.7 a | 2740.0 ± 440.6 a |
Data are means ± standard error. x expressed as the sum of all of the individual identified phenolics (summation), in mg/100 g dry weight of the most relevant standard. y expressed as the separate analysis of the total phenolics for each extract (total extracts), in mg gallic acid equivalents/100 g dry weight. Means followed by different letters within a cultivar are significantly different (p ≤ 0.05; Tukey’s tests); nd, not detected.