Identified metabolites that displayed significant differences between the OA and RA groups.
| RT-m/z (ionization mode) | Molecular Formula | Fragmentation | Metabolite | Peak Intensity | p | Related Metabolism | |
|---|---|---|---|---|---|---|---|
| OA | RA | ||||||
| 0.55_189.17 [M+H] | C9H20N2O2 | C6H14N (–CO2) | N6,N6,N6-Trimethyl-L-lysine | 2.83 | 1.59 | 0.046 | Carnitine |
| 0.59_150.02 [M+2Na] | C7H15NO3 | C4H7O3 (–C3H9N) | 5-L-Glutamyltaurine | 5.63 | 7.95 | 0.036 | Taurine |
| 0.60_162.12 [M+H] | C7H15NO3 | C4H7O3 (–C3H9N) | L-Carnitine | 72.06 | 57.16 | 0.039 | Carnitine |
| 0.62_169.05 [M+H] | C8H8O4 | C7H7O2(–CO2H) | 3-Hydroxymandelic acid | 32.79 | 26.17 | 0.006 | Phenylalanine and tyrosine |
| 0.63_124.01 [M–H] | C2H7NO3S | C2H6NO2S (–H2O) | Taurine | 10.66 | 14.58 | 0.044 | Taurine |
| 0.72_135.01 [M+H] | C3H6N2O4 | C3H6N2O4(–CO H2N) | (S)-Ureidoglycolic acid | 34.58 | 58.87 | 0.003 | Purine |
| 1.39_166.09 [M+H] | C6H7N5O | C5H4N5O(–C H3) | Methylguanine | 18.64 | 25.12 | 0.016 | Purine |
| 3.17_145.06[M–H2O–H] | C10H12N2O3 | C9H11N2O(–CO2H) | Kynurenine | 9.39 | 5.07 | 0.024 | Tryptophan |
| 4.47_204.06 [M–H] | C11H11NO3 | C10H10NO(–CO2H) | Indolelactic acid | 30.53 | 17.99 | 0.046 | Tryptophan |
| 4.48_158.059 [M–H] | C10H9NO | C10H8N(–OH) | Indoleacetaldehyde | 4.94 | 2.70 | 0.039 | Tryptophan |
| 4.77_130.07 [M+H] | C11H12N2O4 | C10H9NO2(–CO2H3N) | N′-Formylkynurenine | 5.65 | 2.22 | 0.050 | Tryptophan |
| 6.27_167.07 [M+H] | C9H10O3 | C7H7(–C2O3H3) | Phenylactic acid | 3.73 | 2.67 | 0.010 | Phenylalanine and tyrosine |
| 6.35_119.09 [M+3H] | C20H34O5 | C17H30O3(–C3H4O2) | Trihydroxyeicosatrienoic acid/13,14-Dihydrolipoxin A4 | 8.22 | 6.03 | 0.039 | Arachidonic acid |
| 6.68_197.09 [M+2Na] | C20H28O5 | C17H24O3(–C3H4O2) | 12,20-Dioxoleukotriene B4 | 2.34 | 1.66 | 0.029 | Arachidonic acid |
| 7.25_211.11 [M+2Na] | C22H32O5 | C19H27O2(–C3O3H5) | 11β-Hydroxy-3,20-dioxopregn-4-en-21-oic acid | 7.85 | 5.84 | 0.006 | Corticosterone |
| 9.99_280.66 [M+H+K] | C26H54NO7P | C5H13O5P (–C21H42NO2) | LysoPC(18:1) | 19.00 | 15.38 | < 0.001 | Glycophospholipid |
| 10.35_260.66 [M+2H] | C51H90O2 | C27H46O(C24H44O) | CE[24:1(15Z)] | 1.72 | 5.98 | < 0.001 | Cholesterol ester |
| 11.01_255.23 [M–H] | C16H32O2 | C15H31 (–CO2H) | Trimethyltridecanoic acid | 95.03 | 117.79 | 0.009 | Beta-oxidation of pristanic acid |
| 11.01_279.24 [M+Na] | C16H32O2 | C15H31 (–CO2H) | Trimethyltridecanoic acid | 18.75 | 24.22 | 0.011 | Beta-oxidation of pristanic acid |
| 11.95_285.29 [M+2Na+H] | C22H34O2 | C21H33 (–CO2H) | Docosapentaenoic acid | 7.26 | 9.51 | 0.040 | Linolenic acid and linoleic acid |
| 13.64_722.56 [M+Na] | C40H77NO8 | C6H11(–C34H66NO8) | Galactosylceramide (d18:1/16:0)/Glucosylceramide (d18:1/16:0) | 9.05 | 10.64 | 0.044 | Sphingolipid |
OA: osteoarthritis; RA: rheumatoid arthritis.