TABLE 2.
Correlation of hydroxycinnamic acid derivatives and flavonol glycosides (mg g–1 dry weight) and biological functions as antioxidants (singlet oxygen scavenging capacity and hydroxyl radical scavenging capacity) and ultraviolet radiation shielding (absorbance) in kohlrabi.
| Retention time | Singlet oxygen scavenging capacity | Hydroxyl radical scavenging capacity | Absorbance | |
| Hydroxycinnamic acid derivatives | ||||
| 3-Caffeoylquinic acid | 6.2 | –0.101751 | 0.137149 | 0.188011 |
| Caffeoyl-glucoside | 6.6 | 0.300800 | 0.139749 | 0.446213 |
| Feruloyl-glucoside | 11.6 | –0.018152 | –0.001907 | –0.298706 |
| Sinapoyl-glucoside | 13.2 | 0.078954 | 0.048242 | 0.700352 |
| Unknown | 20.6 | 0.136176 | 0.244739 | –0.158513 |
| Unknown | 22.1 | –0.031982 | 0.027816 | –0.271488 |
| Unknown | 24.2 | –0.172506 | 0.284134 | 0.042835 |
| Disinapoyl-gentiobiose | 37.0 | –0.084294 | 0.145878 | 0.080536 |
| Sinapoyl-Feruloyl-gentiobiose | 37.6 | 0.154490 | 0.138082 | 0.271076 |
| Disinapoyl-glucoside | 41.5 | –0.091963 | –0.038959 | 0.122176 |
| Trisinapoyl-gentiobiose | 44.1 | –0.239872 | 0.206963 | –0.092451 |
| Disinapoyl-feruloyl-gentiobiose | 44.8 | 0.072664 | 0.047670 | 0.415865 |
| Non-acylated flavonol glycosides | ||||
| Quercetin-3-sophoroside-7-glucoside | 8.6 | 0.202437 | 0.124999 | 0.508333 |
| Kaempferol-3-sophoroside-7-glucoside | 9.2 | 0.147052 | 0.097162 | 0.371887 |
| Quercetin-3-triglucoside | 9.4 | 0.124553 | 0.022812 | 0.569440 |
| Kaempferol-3-sophoroside-7-diglucoside | 10.5 | –0.178689 | –0.035190 | –0.363275 |
| Acylated flavonol glycosides | ||||
| Quercetin-3-sophoroside-7-sinapoyl-diglucoside | 14.5 | 0.071770 | 0.034289 | 0.490458 |
| Quercetin-3-sinapoyl-sophoroside-7-glucoside | 14.9 | 0.070899 | –0.202322 | 0.166614 |
| Kaempferol-3-sinapoyl-sophoroside-7-diglucoside | 16.1 | 0.264322 | 0.061002 | 0.196169 |
| Kaempferol-3-sinapoyl-sophoroside-7-glucoside | 16.6 | 0.308640 | 0.102392 | 0.491060 |
| Kaempferol-3-feruloyl-sophoroside-7-glucoside | 16.9 | 0.337465 | 0.100600 | 0.493892 |
| Kaempferol-3-coumaroyl-sophoroside-7-glucoside | 17.2 | 0.255314 | –0.004100 | 0.694317 |
| Kaempferol-3-sinapoyl,caffeoyl-triglucoside-7-diglucoside | 28.4 | 0.006828 | –0.023776 | –0.211027 |
| Quercetin-3-sinapoyl-triglucoside-7-sinapoyl-diglucoside | 29.1 | –0.181499 | 0.012428 | 0.057980 |
| Quercetin-3-disinapoyl-triglucoside-7-glucoside | 30.3 | –0.056011 | –0.021571 | 0.375379 |
| Quercetin-3-disinapoyl-triglucoside-7-diglucoside | 30.4 | –0.035954 | –0.005042 | 0.352710 |
| Kaempferol-3-disinapoyl-triglucoside-7-glucoside | 31.7 | 0.127330 | –0.011764 | 0.673996 |
Results include three biological replicates each measured as technical duplicates. Bold values indicate significant correlations p ≤ 0.05.