Table 1. Forty-seven FFAs detected by UPLC-QTOF-MS and analyzed by PLS-DA and the Mann−Whitney U-test.
| FFA | Retention time (RT) | VIPa | P-valueb | FCc |
|---|---|---|---|---|
| SFAs | ||||
| C8.0 | 0.98 | 0.54 | 0.9406 | 1.03 |
| C12.0 | 2.52 | 1.05 | 0.1853 | −1.18 |
| C14.0 | 4.52 | 0.83 | 0.0795 | 1.14 |
| C16.0 | 7.31 | 0.92 | 0.008 | 1.49 |
| C18.0 | 10.92 | 0.98 | 0.173 | 1.15 |
| C20.0 | 13.7 | 1.24 | 0.4199 | 1.1 |
| C22.0 | 15.36 | 0.83 | 0.6836 | −1.14 |
| C24.0 | 16.52 | 1.02 | 0.0181 | −1.22 |
| MUFAs | ||||
| C12.1.cis.11 | 1.73 | 0.8 | 0.5958 | 1.25 |
| C14.1.cis.9 | 2.84 | 1.14 | 0.0034 | 2.25 |
| C16.1.cis.9 | 4.88 | 1.32 | 9.23E−06 | 2.67 |
| C18.1.cis.9 | 7.68 | 0.97 | 0.001 | 1.67 |
| C20.1.cis.11 | 11.12 | 1.33 | 7.97E−08 | 3.18 |
| C22.1.cis.13 | 13.7 | 1.5 | 7.97E−08 | 3.7 |
| C24.1.cis.15 | 15.27 | 1.77 | 2.05E−08 | 1.88 |
| ω-6 PUFAs | ||||
| C18.2.cis.9.12 | 5.49 | 0.59 | 0.2364 | 1.34 |
| C20.2.cis.11.14 | 8.27 | 0.95 | 0.007 | 1.61 |
| C20.3.cis.8.11.14 | 6.25 | 0.92 | 0.0131 | 1.34 |
| C20.4.cis.5.8.11.14 | 5.07 | 1.53 | 0.0038 | 1.4 |
| C22.2.cis.13.16 | 11.67 | 1.1 | 0.0046 | 2.11 |
| C22.4.cis.7.10.13.16 | 7.15 | 0.92 | 0.0351 | 1.47 |
| C22.5.cis.4.7.10.13.16 | 6.13 | 1.12 | 0.6627 | 1.14 |
| ω-3 PUFAs | ||||
| C20.5.cis.5.8.11.14.17 | 3.67 | 0.84 | 0.6709 | 1.15 |
| C22.3.cis.13.16.19 | 9.29 | 0.9 | 1 | −1.01 |
| C22.5.cis.7.10.13.16.19 | 5.41 | 1.02 | 0.0204 | 1.5 |
| C22.6.cis.4.7.10.13.16.19 | 4.57 | 1.09 | 0.9856 | 1.06 |
| TFAs | ||||
| C14.1.trans.9 | 3.13 | 1.18 | 0.4026 | 1.34 |
| C16.1.trans.9 | 5.22 | 0.4 | 0.9511 | 1.21 |
| C18.2.trans.9.12 | 6.19 | 0.87 | 0.4199 | 1.09 |
| BCFAs | ||||
| C14.0.iso | 4.23 | 1.19 | 0.4026 | −1.1 |
| C16.0.iso | 6.9 | 0.88 | 0.9511 | −1.05 |
| C18.0.iso | 10.42 | 0.77 | 0.571 | 1.09 |
| OCFAs | ||||
| C15.0.iso | 5.38 | 0.62 | 0.975 | −1.54 |
| C15.0 | 5.82 | 0.67 | 0.9018 | −1.89 |
| C17.1.cis.10 | 6.19 | 0.96 | 0.0012 | 1.86 |
| C17.0.iso | 9.04 | 0.78 | 0.8718 | 1.02 |
| C17.0 | 8.41 | 1.08 | 0.1955 | 1.11 |
| C19.2.cis.10.13 | 6.83 | 0.79 | 0.1062 | 1.22 |
| C19.1.cis.10 | 9.36 | 0.8 | 0.0087 | 2.65 |
| C19.0 | 12.52 | 0.98 | 0.4199 | 1.07 |
| C21.1.cis.12 | 12.6 | 1 | 0.3891 | 1.12 |
| C21.0 | 14.62 | 0.54 | 0.975 | −1.14 |
| C23.1.cis.14 | 14.24 | 0.29 | 0.8586 | 1.02 |
| C23.0 | 15.96 | 1.19 | 0.2436 | −1.18 |
| Others | ||||
| C18.2.CLA | 5.8 | 1.08 | 0.9406 | 1.54 |
| C16.1.unknown | 5.02 | 0.7 | 0.2106 | 1.6 |
| C18.3.unknown | 4.15 | 1.12 | 0.9406 | 1.14 |
Abbreviations: FFA, free fatty acid; MUFA, monounsaturated fatty acid; PUFA, polyunsaturated fatty acids; SFA, saturated fatty acid.
a
Variable importance in the projection (VIP) was obtained from PLS-DA. The black bold values indicate VIP>1.
b
P-values are calculated from the nonparametric Mann−Whitney U-test. The black bold values indicate P<0.05
c
Fold changes (FCs) were calculated from the intra-group means of FFAs, with a positive value indicating a relatively higher concentration in SCZ and a negative value indicating a relatively lower concentration compared to concentration in the healthy controls. The black bold numbers indicate that the absolute value of the FC is >1.5.