Table 2.
Urinary metabolites tentatively identified as potential biomarkers of nut intake1
| N. Cluster | RT (min) | Detected mass (m/z) | Theoretical mass (m/z) | Error (mDa) | Assignation | Potential biomarker | VIP |
|---|---|---|---|---|---|---|---|
| Markers of the polyphenol microbial metabolism | |||||||
| 1 | 6.45 | 227.0327 | 227.0350 | 2.3 | [M – H]− | Urolithin A | 3.75 |
| 228.0365 | 228.0384 | 1.9 | 13C[M – H]− | 2.56 | |||
| 2 | 5.38 | 403.0626 | 403.0671 | 4.5 | [M – H]− | Urolithin A glucuronide | 4.78 |
| 404.0663 | 404.0705 | 4.1 | 13C[M – H]− | 4.38 | |||
| 227.0329 | 227.0350 | 2.1 | [M – H – glucuronide]− | 3.43 | |||
| 3 | 6.64 | 306.9884 | 306.9918 | 3.4 | [M – H]− | Urolithin A sulphate | 3.96 |
| 4 | 5.23 | 483.0187 | 483.0239 | 5.2 | [M – H]− | Urolithin A sulphoglucuronide | 3.01 |
| 5 | 6.80 | 211.0387 | 211.0401 | 1.4 | [M – H]− | Urolithin B | 2.00 |
| 6 | 6.30 | 387.0650 | 387.0721 | 7.1 | [M – H]− | Urolithin B glucuronide | 2.44 |
| - | 388.0708 | 388.0755 | 4.7 | 13C[M – H]− | 2.23 | ||
| - | - | 211.0386 | 211.0401 | 1,5 | [M – H – glucuronide]− | - | - |
| 7 | 5.00 | 151.0579 | 151.0594 | 1.5 | 13C[M – H – COO]− | Hydroxyhippuric acid | 2.66 |
| - | - | 150.0529 | 150.0560 | 3,1 | [M – H – COO]- | - | - |
| - | 4.98 | 194.0367 | 194.0459 | 9,2 | [M – H]- | - | - |
| 8 | 4.50 | 151.0383 | 151.0401 | 1.8 | [M – H]− | 2-Hydroxyphenylacetic acid | 3.59 |
| Markers of the polyphenol intestinal metabolism | |||||||
| 9 | 6.95 | 307.0265 | 307.0282 | 1.7 | [M – H]− | Resveratrol-sulphate | 2.99 |
| - | - | 308.0285 | 308.0316 | 3.1 | 13C[M – H]- | - | - |
| 227.0702 | 227.0714 | 1.2 | [M – H – sulphate]− | 2.72 | |||
| - | - | 228.0732 | 228.0748 | 1.6 | 13C[M – H – sulphate]− | - | - |
| Markers of the fatty acid metabolism | |||||||
| 10 | 6.77 | 229.1429 | 229.1445 | 1.6 | [M – H]− | Dodecanedioic acid | 2.15 |
| 230.1468 | 230.1479 | 1.1 | 13C[M – H]− | 2.06 | |||
| 11 | 4.07 | 160.0700 | 160.0697 | 0.3 | 13C[M – H]− | Dimethylglutaric acid | 2.70 |
| - | - | 159.0664 | 159.0663 | 0.1 | [M – H]- | - | - |
| 115.0769 | 115.0764 | 0.5 | [M – H – COO]− | 2.09 | |||
| - | - | 97.0657 | 97.0659 | 0.2 | [M – H – COO – H2O]- | - | - |
| Markers of the tryptophan metabolism | |||||||
| 12 | 5.28 | 175.0265 | 175.0594 | 0.3 | 13C[M – H – glucuronide]− | Indole-3-acetic acid glucuronide | 2.08 |
| - | - | 174.0569 | 174.0560 | 0.9 | [M – H – glucuronide]- | - | - |
| - | - | 351.0911 | 351.0915 | 0.4 | 13C[M – H]- | - | - |
| - | - | 350.0878 | 350.0881 | 0.3 | [M – H]- | - | - |
| 13 | 4.55 | 212.0018 | 212.0023 | 0.5 | [M – H]− | Indoxyl sulphate / Indoxylsulphuric acid | 2.58 |
| 213.0048 | 213.0057 | 0.9 | 13C[M – H]− | 2.05 | |||
| 132.0448 | 132.0455 | 0.7 | [M – H – sulphate]− | 2.13 | |||
| - | - | 425.0117 | 425.0119 | 0.2 | [2M– H]− | - | - |
| Markers of the benzoxazinoid biosynthesis | |||||||
| 14 | 4.93 | 180.0373 | 180.0302 | 7.1 | [M – H]− | Dihydroxy-benzoxazinone | 3.14 |
| Unidentified markers | |||||||
| 15 | 6.70 | 309.0409 | [M – H]− | Unknown A (sulphate derivative) | 3.19 | ||
| 310.0437 | 13C[M – H]− | 2.27 | |||||
| 311.0381 | 213C[M – H]− | 2.48 | |||||
| 16 | 6.15 | 359.1329 | [M – H]− | Unknown B (glucuronide derivative) | 2.04 | ||
| - | - | 183.1024 | - | - | [M – H – glucuronide]- | - | - |
| 17 | 6.54 | 397.1102 | [M – H]− | Unknown C | 2.66 | ||
| - | - | 398.1141 | 398,1136 | 0,5 | 13C[M – H]- | - | - |
| 18 | 6.22 | 373.1150 | [M – H]− | Unknown D | 2.25 | ||
| 374.1126 | 13C[M – H]− | 2.34 | |||||
1
One-class OSC-PLS-DA model (NC versus RC) was used. NC, non-nut consumers; RT, retention time; VIP, variable importance projection; RC, regular nut consumers. Most important MS/MS fragments that were used in the identification fo the metabolites with VIP <2 are also included in the table.