Table 2. Characteristics of the 14 candidate biomarkers.
| Compound Classification | p-value | RT (min) | XCMS average m/z | Fold change | Molecular formula | MS/MS major fragments (% abundance)a | FTMS accurate mass |
| Fatty acid/Sterol lipid | 6.32×10−13 | 45.7 | 521.4197 | −3.36 | C32H56O5 | 111.0451(39.15)503.4123(29.7) | 521.4190 |
| Fatty acid/Sterol lipid | 2.06×10−11 | 45.7 | 469.3872 | −3.71 | C28H52O5 | 415.357(100)291.2331(48.57) | 469.3888 |
| Sterol lipid | 2.16×10−11 | 41.4 | 425.3611 | −3.55 | C26H48O4 | 389.3432(100.0)139.1107(12.8) | 425.3625 |
| Protein | 3.59×10−10 | 31.6 | 979.9368 | −3.99 | - | ||
| Protein | 6.53×10−10 | 31.5 | 986.2677 | −5.65 | - | ||
| Hexacosenoic acid | 4.01×10−10 | 50.7 | 395.3867 | −2.77 | C26H50O2 | 71.0859(100.0)57.0709(81.99) | 395.3804 |
| Pentacosenoic acid | 7.75×10−10 | 49.1 | 381.3710 | −2.43 | C25H48O2 | 71.0858(100.0)57.0719(58.75) | 381.3728 |
| Fatty alcohol/aldehyde | 2.39×10−8 | 48.5 | 241.2505 | 1.54 | C16H32O | 55.0551(77.61)83.0877(46.81) | —b |
| Fatty acid | 1.40×10−9 | 39.0 | 367.2840 | −2.28 | C22H38O4 | 331.2649(100.0)79.0547(33.89) | 367.2828 |
| Hydroxy-octadecenoic acid | 1.52×10−9 | 46.1 | 299.2581 | −2.54 | C18H34O3 | 95.0851(100)71.0863(82.07) | 299.2592 |
| Phosphorylated sphingolipid | 4.83×10−9 | 30.0 | 352.2256 | −1.55 | C16H34NO5P | 236.2366(100.0)184.0694(25.99) | 352.2247 |
| Sterol lipid | 1.44×10−8 | 45.5 | 447.3470 | −2.19 | C28H46O4 | 429.3376(43.06)411.3276(32.91) | 447.3470 |
| Protein | 2.05×10−8 | 33.3 | 966.5938 | −3.09 | - | ||
| Protein | 5.24×10−8 | 31.7 | 1086.2922 | −2.76 | - |
a
Fragments collected under a collision-induced dissociation energy of 20 eV.
b
FTMS accurate mass was not obtained for this compound. This formula is based on TOF-MS mass accuracy.
Statistical values such as p-value and fold change were determined by XCMS analysis of the O. volvulus + and O. volvulus − mass spectral data files. Retention time (RT), and mass to charge value (m/z), fold change and the direction of overall ion intensity change, represents the average value across all files. Molecular formula and compound class identifier as determined by MS/MS and FTMS analysis is provided.