Table 1.
Phenolic compounds (mg/g of dry weight (DW)) of Robinia pseudoacacia L. leaf and flower extracts were identified by LC-MS. Values represent the mean ± standard deviation of three replicates. Different letters indicate a significant difference among the values in a row (ANOVA, Tukey’s honest significant difference, p ≤ 0.01); nd = not detected.
| Phenolic Compounds | Robinia pseudoacacia Leaf | Robinia pseudoacacia Flower | ||
|---|---|---|---|---|
| 70% EtOH | 80% MeOH | 70% EtOH | 80% MeOH | |
| 3-Caffeoylquinic acid | 0.454 ± 0.057 a | 0.355 ± 0.043 a | 0.123 ± 0.041 b | 0.037 ± 0.003 b |
| 5-Caffeoylquinic acid | 0.011 ± 0.000 a | 0.010 ± 0.001 ab | 0.005 ± 0.001 c | 0.006 ± 0.001 bc |
| Caffeic acid | 0.346 ± 0.054 a | 0.236 ± 0.024 b | 0.100 ± 0.018 c | 0.059 ± 0.008 c |
| Caffeic acid hexoside 1 | 0.242 ± 0.010 a | 0.224 ± 0.038 a | 0.029 ± 0.001 b | 0.022 ± 0.002 b |
| Caffeic acid hexoside 2 | 0.039 ± 0.001 a | 0.021 ± 0.005 b | 0.003 ± 0.000 c | 0.004 ± 0.001 c |
| p-Coumaric acid | 0.152 ± 0.009 a | 0.116 ± 0.039 a | n.d. | n.d. |
| p-Coumaric acid hexoside 1 | 0.052 ± 0.002 a | 0.048 ± 0.008 b | 0.007 ± 0.001 a | 0.006 ± 0.002 b |
| p-Coumaric acid hexoside 2 | 0.287 ± 0.011 a | 0.118 ± 0.035 b | 0.026 ± 0.006 c | 0.068 ± 0.014 c |
| 3-p-Coumaroylquinic acid | 0.102 ± 0.001 a | 0.086 ± 0.004 b | 0.001 ± 0.000 c | 0.002 ± 0.000 c |
| 4-p-Coumaroylquinic acid | 0.003 ± 0.002 a | 0.002 ± 0.002 a | 0.003 ± 0.001 a | 0.001 ± 0.000 a |
| 5-p-Coumaroylquinic acid 1 | 0.109 ± 0.003 b | 0.087 ± 0.011 b | 0.409 ± 0.123 a | 0.056 ± 0.011 b |
| 5-p-Coumaroylquinic acid 2 | 0.084 ± 0.004 ab | 0.046 ± 0.016 c | 0.059 ± 0.005 bc | 0.101 ± 0.005 a |
| 3-Feruloylquinic acid | 0.033 ± 0.001 a | 0.018 ± 0.004 b | 0.002 ± 0.000 c | 0.004 ± 0.000 c |
| Ferulic acid | 0.006 ± 0.000 a | 0.006 ± 0.000 a | n.d. | n.d. |
| Sinapic acid derivate | 0.036 ± 0.001 a | 0.031 ± 0.002 b | n.d. | n.d. |
| Hydroxycinnamic acid derivatives | 1.956 ± 0.100 a | 1.451 ± 0.155 c | 0.603 ± 0.246 b | 0.349 ± 0.100 d |
| Gallic acid | 0.361 ± 0.026 a | 0.247 ± 0.041 b | 0.137 ± 0.017 c | 0.091 ± 0.008 c |
| Ellagic acid | 0.005 ± 0.000 c | 0.006 ± 0.001 c | 0.115 ± 0.010 b | 0.137 ± 0.004 a |
| Ellagic acid hexoside | 1.137 ± 0.029 a | 0.572 ± 0.004 b | 0.249 ± 0.022 d | 0.441 ± 0.019 c |
| Protocatehuic acid | 0.192 ± 0.024 | 0.154 ± 0.012 | 0.025 ± 0.001 | 0.016 ± 0.001 |
| p-Hydroxybenzoic acid | 0.518 ± 0.013 b | 0.393 ± 0.070 a | n.d. | n.d. |
| Hydroxybenzoic acid derivatives | 2.076 ± 0.272 a | 1.014 ± 0.751 b | 0.513 ± 0.039 b | 0.682 ± 0.028 b |
| Apigenin glucuronyl rhamnosylhexoside | 1.036 ± 0.114 a | 1.220 ± 0.133 a | 0.051 ± 0.005 b | 0.091 ± 0.004 b |
| Luteolin rhamnosyl hexoside 1 | 0.009 ± 0.001 c | 0.003 ± 0.000 c | 3.075 ± 0.142 b | 1.748 ± 0.163 a |
| Luteolin rhamnosyl hexoside 2 | 0.130 ± 0.015 c | 0.153 ± 0.015 c | 1.281 ± 0.111 b | 1.524 ± 0.040 a |
| Luteolin dirhamnosyl hexoside 1 | 0.451 ± 0.048 c | 0.133 ± 0.027 c | 6.990 ± 0.652 b | 12.299 ± 0.566 a |
| Luteolin dirhamnosyl hexoside 2 | 0.013 ± 0.001 c | 0.016 ± 0.001 c | 1.404 ± 0.161 b | 2.459± 0.106 a |
| Flavones | 1.52 ± 0.352 c | 1.486 ± 0.226 c | 11.474 ± 1.074 b | 19.448 ± 0.842 a |
| Procyanidin dimer 1 | 3.552 ± 0.194 a | 2.695 ± 0.493 a | 0.487 ± 0.070 b | 0.479 ± 0.036 b |
| Procyanidin dimer 2 | 4.890 ± 0.205 a | 3.396 ± 0.291 b | 0.128 ± 0.013 c | 0.131 ± 0.038 c |
| Procyanidin dimer 3 | 2.132 ± 0.255 a | 1.643 ± 0.285 a | 0.039 ± 0.008 b | 0.018 ± 0.002 b |
| Procyanidin dimer 4 | 1.294 ± 0.196 b | 0.916 ± 0.191 b | 2.612 ± 0.272 a | 0.158 ± 0.020 c |
| Procyanidin trimer 1 | 4.055 ± 0.065 a | 3.429 ± 0.192 b | 0.031 ± 0.007 c | 0.042 ± 0.007 c |
| Procyanidin trimer 2 | 1.214 ± 0.047 a | 0.668 ± 0.144 b | 0.327 ± 0.066 c | 0.161 ± 0.016 c |
| Procyanidin trimer 3 | 2.958 ± 0.045 a | 2.227 ± 0.246 b | 0.026 ± 0.005 c | 0.012 ± 0.002 c |
| Procyanidin trimer 4 | 3.214 ± 0.092 a | 2.646 ± 0.368 b | n.d. | n.d. |
| Procyanidin trimer 5 | 0.235 ± 0.028 a | 0.164 ± 0.046 b | n.d. | n.d. |
| Procyanidin tetramer 1 | 0.728 ± 0.028 a | 0.401 ± 0.086 b | n.d. | n.d. |
| Procyanidin tetramer 2 | 2.949 ± 0.049 a | 1.844 ± 0.223 b | n.d. | n.d. |
| Epicatechin | 0.013 ± 0.002 c | 0.009 ± 0.002 c | 0.251 ± 0.012 a | 0.105 ± 0.014 b |
| Catechin | 6.221 ± 0.194 a | 5.907 ± 0.493 a | 0.576 ± 0.081 b | 0.871 ± 0.141 b |
| Gallocatechin | 1.003 ± 0.043 a | 0.620 ± 0.077 b | 0.366 ± 0.081 c | 0.520 ± 0.054 c |
| Flavanols | 32.806 ± 2.113 a | 24.357 ± 3.528 b | 4.126 ± 0.667 c | 2.134 ± 0.866 c |
| Quercetin pentoside | n.d. | n.d. | 0.002 ± 0.000 a | 0.002 ± 0.000 a |
| Quercetin-3-galactoside | 0.275 ± 0.028 a | 0.233 ± 0.035 a | 0.107 ± 0.014 b | 0.134 ± 0.005 b |
| Quercetin-3-glucoside | 0.022 ± 0.001 c | 0.029 ± 0.004 c | 0.051 ± 0.004 b | 0.061 ± 0.002 a |
| Quercetin-3-rutinoside | 0.179 ± 0.020 b | 0.311 ± 0.047 b | 0.299 ± 0.085 b | 0.519 ± 0.033 a |
| Quercetin rhamnosyhexoside | 0.219 ± 0.047 b | 0.139 ± 0.021 b | 1.383 ± 0.160 a | 0.027 ± 0.002 b |
| Kaempferol hexoside 1 | n.d. | n.d. | 0.003 ± 0.001 a | 0.004 ± 0.000 a |
| Kaempferol hexoside 2 | n.d. | n.d. | 0.274 ± 0.020 a | 0.292 ± 0.011 a |
| Kaempferol hexoside 3 | n.d. | n.d. | 0.081 ± 0.012 b | 0.126 ± 0.013 a |
| Kaempferol-3-glucoside | 0.200 ± 0.029 a | 0.170 ± 0.017 a | n.d. | n.d. |
| Kaempferol rhamnosyl hexoside 1 | 0.001 ± 0.000 c | 0.001 ± 0.000 c | 0.252 ± 0.029 b | 0.537 ± 0.015 a |
| Kaempferol rhamnosyl hexoside 2 | 0.324 ± 0.030 a | 0.232 ± 0.025 b | 0.051 ± 0.015 c | 0.089 ± 0.006 c |
| Kaempferol rhamnosyl hexoside 3 | 0.091 ± 0.005 c | 0.120 ± 0.015 bc | 0.172 ± 0.028 a | 0.140 ± 0.007 ab |
| Kaempferol glucuronyl rhamnosyl hexoside 1 | 0.105 ± 0.011 b | 0.135 ± 0.025 ab | 0.114 ± 0.012 b | 0.174 ± 0.018 a |
| Kaempferol glucuronyl rhamnosyl hexoside 2 | 5.521 ± 0.623 a | 3.181 ± 0.182 b | 0.272 ± 0.033 c | 0.463 ± 0.041 c |
| Isorhamnetin-3-rutinoside | 1.041 ± 0.095 a | 1.248 ± 0.128 a | 0.228 ± 0.046 b | 0.390 ± 0.088 b |
| Isorhamnetin hexoside 1 | 0.005 ± 0.000 b | 0.003 ± 0.000 b | 0.072 ± 0.025 a | 0.094 ± 0.004 a |
| Isorhamnetin hexoside 2 | 0.093 ± 0.018 a | 0.058 ± 0.003 b | 0.010 ± 0.001 c | 0.017 ± 0.002 c |
| Myricetin hexoside | 0.090 ± 0.011 b | 0.053 ± 0.003 c | 0.061 ± 0.007 c | 0.130 ± 0.004 a |
| Robinetin | 0.001 ± 0.000 c | 0.002 ± 0.000 b | 0.003 ± 0.000 b | 0.003 ± 0.000 a |
| Dihydrorobinetin | 0.081 ± 0.001 a | 0.068 ± 0.003 b | 0.004 ± 0.001 b | 0.006 ± 0.001 c |
| Flavonols | 8.226 ± 0.656 a | 5.843 ± 0.660 b | 3.457 ± 0.220 c | 3.171 ± 0.162 c |
| Naringenin hexoside 1 | 0.092 ± 0.007 b | 0.142 ± 0.014 a | 0.043 ± 0.003 d | 0.070 ± 0.005 c |
| Naringenin hexoside 2 | 0.082 ± 0.009 a | 0.058 ± 0.014 ab | 0.057 ± 0.014 ab | 0.031 ± 0.010 b |
| Naringenin hexoside 3 | 0.294 ± 0.039 a | 0.202 ± 0.020 b | 0.038 ± 0.008 c | 0.024 ± 0.005 c |
| Flavanones | 0.468 ± 0.052 a | 0.362 ± 0.113 a | 0.127 ± 0.010 b | 0.125 ± 0.017 b |
| Vescalagin 1 | 3.296 ± 0.347 b | 1.021 ± 0.090 c | 3.436 ± 0.306 b | 5.863 ± 0.290 a |
| Vescalagin 2 | 2.031 ± 0.181 a | 1.364 ± 0.156 b | 0.642 ± 0.105 c | 0.971 ± 0.139 bc |
| Ellagitannins | 5.327 ± 0.274 ab | 1.789 ± 0.805 c | 4.078 ± 0.376 b | 6.834 ± 0.418 a |
| Total Analyzed Phenolics | 52.717 ± 2.531 a | 36.742 ± 3.588 b | 24.853 ± 2.052 c | 32.743 ± 2.2689 bc |
The external standards used: caffeic acid, apigenin-7-glucoside, ferulic acid, quercetin-3-O-rhamnoside, neochlorogenic (3-caffeoylquinic) acid, naringenin, ellagic acid, gallic acid, chlorogenic acid, and rutin (quercetin-3-O-rutinoside); (-)epicatechin, quercetin-3-O-galactoside, quercetin-3-O-glucoside, p-coumaric acid, procyanidin B1, and kaempferol-O-glucoside; quercetin-3-O-xyloside and quercetin-3-O-arabinopyranoside; and isorhamnetin-3-O-glucoside.