Table 2.

Discriminated metabolites of urine identified using UPLC-Q-TOF-MS.

RT (min)	Measured MS (m/z)		Tentative Metabolites	Molecular Formula		Error (mDa)		Adduct	Fold Change (1)
	Positive	Negative							HFD/ND	HFDC/HFD	HFDC/ND
3.01	180.0844	-	Hydroxyadipic acid	C6H10O5		−2.8		[M+NH4]+	1.682 *	0.875	1.472
3.47	395.0942	393.0828	Dihydroferulic acid 4-O-glucuronide	C16H20O10		−3.0		[M+H]+	0.018 *	9.641	0.176 *
3.69	338.0864	336.0749	3-Indole carboxylic acid glucuronide	C15H15NO8		−5.3		[M+H]+	0.071 *	3.864	0.273
3.93	340.0992	338.0895	5-hydroxy-6-methoxyindole glucuronide	C15H17NO8		−4.0		[M+H]+	0.024 *	0.066	0.002 *
4.38	164.0714	162.0549	3-Methyldioxyindole	C9H9NO2		0.2		[M+H]+	0.003 *	6.066	0.016
Caffeine metabolites (2)
1.50	171.0899	-	5-Acetylamino-6-amino-3-methyluracil (AAMU)	C7H10N4O3		1.7		[M+H−CO]+
2.57	167.0570	-	7-Methylxanthine	C6H6N4O2		0.1		[M+H]+
2.61	183.0529	-	1-Methyluric acid	C6H6N4O3		1.1		[M+H]+
2.71	167.0569	-	3-Methylxanthine	C6H6N4O2		0.0		[M+H]+
2.77	197.0675	-	3,7-Dimethyluric acid	C7H8N4O3		0.0		[M+H]+
2.79	167.0567	-	1-Mehtylxanthine	C6H6N4O2		−0.2		[M+H]+
2.97	197.0679	-	1,3-Dimethyluric acid	C7H8N4O3		0.4		[M+H]+
3.03	181.0731	-	Theobromine	C7H8N4O2		0.5		[M+H]+
3.20	197.0659	-	1,7-Dimethyluric acid	C7H8N4O3		−1.6		[M+H]+
3.30	181.0733	-	Paraxanthine	C7H8N4O2		0.7		[M+H]+
3.40	211.0835	-	1,3,7-Trimethyluric acid	C8H10N4O3		0.4		[M+H]+
3.69	195.0888	-	Caffeine	C8H10N4O2		0.6		[M+H]+
Not-identified
0.87	109.0762	-	N.I.	-		-		-	2.111	0.291 *	0.614
1.41	126.0916	-	N.I.	-		-		-	1.825 *	1.955 *	3.568 *
1.88	127.0480	-	N.I. (2)	-		-		-
2.90	185.1050	-	N.I. (2)	-		-		-
3.09	185.1057	-	N.I. (2)	-		-		-
3.68	447.2227	-	N.I.	-		-		-	5.643 *	0.738	4.163 *
3.69	393.1527	-	N.I.	-		-		-	1.972 *	1.127	2.222 *
4.80	170.0599	-	N.I.	-		-		-	0.245 *	1.27	0.312 *
5.82	231.1425	-	N.I.	-		-		-	3.263 *	0.771	2.514 *
6.15	354.1368	-	N.I.	-		-		-	0.439 *	1.097	0.481 *
9.47	415.3032	-	N.I.	-		-		-	1.286	0.689 *	0.887

⁽¹⁾ Fold change was calculated by dividing the mean of the peak intensity of each metabolite from each of the two groups; ⁽²⁾ Detected only in the high fat diet with caffeine (HFDC) group; RT, Retention time; N.I., Not identified; ND, normal diet; HFD: high fat diet; HFDC, high fat diet with caffeine; * p value < 0.05, - not detected.