Table 1.
Content compounds of Lycopus leaf infusions, their corresponding retention times (TR), molecular ions [M − H]−, and MS2 fragments in LC-MS/MS analysis, in addition to quantitative abundance of polar phenolic compounds (µg/mL) in four Lycopus infusions.
| Compound | TR (min) | [[M − H]− | MS2 (20 eV) (m/z) |
Mass Concentration (µg/mL)* ± SD | ||||
|---|---|---|---|---|---|---|---|---|
| LeuA | LeuB | LeuC | Lex | |||||
| 1 | Citric acid | 4.76 | 191.0191 | 111.0084 87.0087 85.037 |
ND | LOD | LOD | LOD |
| 2 | Danshensu (trihydroxyphenyl propanoic acid) | 11.64 | 197.0449 | 179.0343 135.0443 |
LOD | LOD | LOD | LOD |
| 3 | Caffeic acid | 21.59 | 179.0342 | 135.0445 | 15.7 ± 1.7 | 16.8 ± 0.2 | 16.9 ± 0.1 | 23.1 ± 0.1 |
| 4 | Quercetin glucuronide | 24.58 | 477.0656 | 301.0332 | 38.1 ± 1.4 | 21.5 ± 0.3 | ND | 84.3 ± 0.3 |
| 5 | Quercetin glucoside | 25.91 | 463.0857 | 301.0324 | 34.0 ± 7.7 | LOD | LOD | LOD |
| 6 | Lithospermic acid | 26.00 | 537.1034 | 359.0739 197.0456 179.0340 161.0235 135.0431 |
LOD | LOD | LOD | 13.9 ± 0.1 |
| 7 | Rosmarinic acid hexoside | 28.42 | 521.1301 | 359.0767 179.0376 161.0223 |
LOD | 17.4 ± 0.6 | 16.3 ± 0.5 | LOD |
| 8 | Luteolin-7-O-glucuronide | 28.57 | 461.0731 | 285.0393 | 315.1 ± 3.6 | 279.6 ± 1.4 | 275.1 ± 0.9 | 449.8 ± 0.4 |
| 9 | Sagerinic acid | 29.96 | 439.0318 | 359.0751 197.8040 161.0232 |
12.0 ± 2.4 | 15.4 ± 0.3 | 12.4 ± 0.2 | 11.1 ± 4.2 |
| 10 | Sulphated rosmarinic acid | 30.37 | 719.1620 | 539.1182 359.0774 161.0450 |
11.8 ± 0.6 | 18.7 ± 0.1 | 16.6 ± 0.4 | 13.0 ± 0.1 |
| 11 | Apigenin-7-O-glucuronide | 34.12 | 445.0753 | 269.0444 | 27.6 ± 0.1 | 23.0 ± 2.7 | 36.5 ± 1.2 | 27.2 ± 0.1 |
| 12 | Rosmarinic acid | 34.48 | 359.0751 | 197.0483 161.0234 |
213.7 ± 0.3 | 237.5 ± 0.8 | 202.3 ± 0.1 | 216.2 ± 0.1 |
| 13 | Caffeic acid derivative | 36.52 | 549.2332 | 359.0767 161.0295 |
19.6 ± 0.3 | LOD | 7.6 ± 0.2 | 168.0 ± 0.3 |
*Values (μg/mL infusion) are presented as means ± standard deviation (n = 3); external standards: luteolin-7-O-glucuronide (used for flavonoid determination), rosmarinic acid (used for phenolic acid determination). ND—not detected; LOD—limit of detection, TR – retention time, LeuA—L. europaeus A; LeuB—L. europaeus B; LeuC—L. europaeus C; Lex—L. exaltatus;