Table 1.
HPLC-MS/MS identification (MRM) of 13C-labelled cyanidin-3-glucoside (C3G) and its metabolites in the serum, urine and faeces of healthy volunteers (n = 8) after the consumption of 500 mg of 13C-labelled C3G
| Metabolite | Compound identification | Analytical standards | |||
|---|---|---|---|---|---|
| Rt (min) | MRM ion transitions (m/z)a | Location | # 13Cb | MS2 fragments (m/z) | |
| Parent anthocyanins | |||||
| Cyanidin-3-glucoside (C3G) | 12.6 | 454/292, 246, 218, 133 | Urine, serum, faeces | +5 | 449/287, 241, 213, 128 |
| Cyanidin-glucuronide | 11.7 | 468/292 | Urine | +5 | NA |
| Cyanidin-glucuronide | 16.5 | 468/292 | Urine | +5 | NA |
| Peonidin-3-glucoside | 16.6 | 468/306 | Urine | +5 | 463/301 |
| Methyl-cyanidin-glucuronide | 16.7 | 482/306 | Urine | +5 | NA |
| Methyl-C3G-glucuronide | 5.7 | 644/306 | Urine | +5 | NA |
| Methyl-C3G-glucuronide | 8.0 | 644/306 | Urine | +5 | NA |
| Methyl-C3G-glucuronide | 9.6 | 644/306 | Urine | +5 | NA |
| Degradants | |||||
| Protocatechuic acid (PCA) | 4.3 | 155/111, 93, 83 | Urine, serum, faeces | +2 | 153/109, 91, 81 |
| Phloroglucinaldehyde | 7.4 | 156/155, 128, 110, 86 | Urine, serum, faeces | +3 | 153/151, 125, 107, 83 |
| Metabolites | |||||
| 3-Hydroxybenzoic acid | 8.1 | 138/95, 67 | Urine, faeces | +2 | 136/93, 65 |
| 4-Hydroxybenzoic acid | 6.5 | 138/95, 67 | Urine, faeces | +2 | 136/93, 65 |
| Benzoic acid-4-glucuronide | 3.0 | 317/175, 155, 113, 95 | Urine, serum, faeces | +2 | 315/175, 153, 113, 93 |
| PCA-3-glucuronide | 4.3 | 331/175, 155, 113, 111 | Urine, serum, faeces | +2 | 329/175, 153, 113, 109 |
| PCA-4-glucuronide | 3.3 | 331/175, 155, 113, 111 | Urine, serum, faeces | +2 | 329/175, 153, 113, 109 |
| PCA-3-sulfate | 6.5 | 235/191, 155, 111 | Urine, serum, faeces | +2 | 233/189, 153, 109, 97 |
| PCA-4-sulfate | 6.2 | 235/191, 155, 111 | Urine, serum, faeces | +2 | 233/189, 153, 109, 97 |
| Vanillic acid (VA) | 9.5 | 169/154, 125, 110 | Urine, serum, faeces | +2 | 167/152, 123,108 |
| IsoVA | 9.9 | 171/153, 127, 95 | Urine, serum, faeces | +2 | 169/151, 125, 93, 65 |
| IsoVA-3-glucuronide | 6.2 | 347/175, 171, 154, 113 | Urine, serum, faeces | +2 | 345/175, 169, 152, 113 |
| VA-4-glucuronide | 4.9 | 347/175, 171, 154, 113 | Urine, serum, faeces | +2 | 345/175, 169, 152, 113 |
| IsoVA-3-sulfate | 8.8 | 247/169, 154, 125, 110 | Urine, serum, faeces | +2 | 245/167, 152, 123, 108 |
| VA-4-sulfate | 8.6 | 247/169, 154, 125, 110 | Urine, serum, faeces | +2 | 245/167, 152, 123, 108 |
| 4-Hydroxyphenylacetic acid | 6.8 | 154/125, 109, 95 | Urine, faeces | +2 | 152/123, 107, 93, 79 |
| 3,4-Dihydroxyphenylacetic acid | 4.6 | 171/127, 111, 97 | Urine, faeces | +2 | 169/125, 109, 95 |
| 4-Hydroxybenzaldehyde | 8.5 | 123/110, 94, 67 | Urine, serum, faeces | +2 | 121/108, 92, 65 |
| 3,4-Dihydroxybenzaldehyde | 5.8 | 139/110, 94, 83 | Urine, faeces | +2 | 137/109, 92, 81 |
| Caffeic acid | 10.4 | 183/139, 110, 93 | Faeces | +2 | 181/137, 108, 91 |
| Ferulic acid | 18.8 | 195/180, 150, 136 | Urine, serum, faeces | +2 | 193/178, 148, 134 |
| 196/181, 151, 137 | Urine, serum, faeces | +3 | |||
| Hippuric acid | 6.3 | 179/136, 134, 79 | Urine, serum, faeces | +2 | 177/134 ,132, 77 |
| 4-Methoxybenzaldehyde | 19.6 | 169/125, 110, 81 | Faeces | +2 | 167/123, 108, 79 |
| 2-Hydroxy-4-methoxybenzoic acid | 20.1 | 155/94, 79, 65 | Faeces | +2 | 153/92,77, 63 |
| 156/95, 80, 66 | Urine | +3 | |||
| Methyl vanillate | 21.4 | 185/153, 125, 109 | Faeces | +2 | 183/151, 123, 107, 77 |
| Methyl-3,4-dihydroxybenzoate | 12.9 | 170/111, 93 | Urine, serum, faeces | +2 | 168/109, 91 |
a
Mass spectra fragments for 13C-labelled metabolites with +2, +3 and +5 m/z.
b
+2, +3 and +5 m/z refer to metabolites derived from PCA, PGA and cyanidin respectively.
NA, no analytical standard available for confirmation.