Table 2.

Potential biomarkers in response to RA and their metabolic pathways.

Mode	Number	t R/min	m/z	Formula	Identification	Folda	P valuea	Related pathway
	1	1.16	104.1076	C5H14NO	Cholineb	26.11	0.000	Glycerophospholipid metabolism
	2	1.19	162.1129	C7H15NO3	Carnitineb	−0.84	0.000	Fatty acid metabolism, oxidative injury
	3	1.20	258.1108	C8H21NO6P	Glycerophosphocholinec	25.39	0.000	Glycerophospholipid metabolism
	4	1.73	204.1235	C9H17NO4	Acetylcarnitinec	0.819	0.006	Fatty acid metabolism, oxidative injury
	5	3.06	166.0869	C9H11NO2	L-Phenylalanineb	0.81	0.005	Phenylalanine metabolism
ESI(+)	6	5.07	180.0661	C9H9NO3	Hippuric acidb	25.27	0.007	Phenylalanine metabolism
	7	5.30	194.0820	C10H11NO3	Phenylacetylglycinec	−0.93	0.004	Phenylalanine metabolism
	8	10.13	357.2796	C24H36O2	DHA ethyl esterc	3.19	0.002	Alpha linolenic acid and linoleic acid metabolism
	9	14.89	400.3427	C23H45NO4	Palmitoyl-L-carnitinec	0.57	0.003	Fatty acid metabolism
	10	16.58	305.2481	C20H32O2	Arachidonic acidb	0.94	0.002	Arachidonic acid metabolism
	11	16.79	271.2637	C17H34O2	Palmitic acid methyl esterc	4.09	0.000	Fatty acid metabolism
	12	1.24	157.0361	C4H6N4O3	Allantoinb	2.13	0.000	Purine metabolism, oxidative injury
	13	1.74	167.0207	C5H4N4O3	Uric acidb	−1.16	0.004	Purine metabolism, oxidative injury
	14	2.19	219.0775	C11H12N2O3	5-Hydroxy tryptophanb	0.99	0.008	Tryptophan metabolism
ESI(−)	15	4.51	203.0831	C11H12N2O2	L-Tryptophanb	1.61	0.003	Tryptophan metabolism
	16	8.34	212.0025	C8H7NO4S	Indoxyl sulfatec	1.27	0.003	Tryptophan metabolism
	17	6.21	464.3024	C26H43NO6	Glycocholic acidc	−0.38	0.022	Bile acid biosynthesis
	18	10.14	391.2855	C24H40O4	Deoxycholic acidc	−0.44	0.046	Bile acid biosynthesis

^aFold changes (calculated as log₂ (average peak intensity of model group/average peak intensity of normal control group) and P value compared with normal control group on day 22.

^bMetabolites validated with standards.

^cMetabolites putatively annotated.