. 2021 Jun 9;8:648823. doi: 10.3389/fmolb.2021.648823

TABLE 2.

Characterization of the significantly different metabolites between the healthy subjects and LDH patients.

Compounds	RT	VIP	Fold change (patients/control)	Main metabolic pathway
1-methylinosine	46.201	1.702	0.587^a,d	Unknown
2,6-dihydroxybenzoic acid methyl ester	27.459	1.512	0.737^a,d	Unknown
2-hydroxy-2-methylbutanoic acid	10.09	1.677	0.652^a,d	Unknown
2-hydroxyhippuric acid	31.964	2.204	0.520^a,c	Unknown
3,4-dihydroxybutanoic acid	18.321	2.702	0.331^b	Unknown
4-hydroxybenzoic acid	22.986	2.626	0.448^a,c	Phenylalanine metabolism
5-hydroxyindole	24.691	2.149	0.491^a,c	Tryptophan metabolism
Creatinine√	21.177	2.131	0.521^a,c	Arginine and proline metabolism
D-glycero-D-gulo-heptose	37.389	1.595	0.690^a,c	Unknown
d-mannitol√	29.345	1.789	5.404^a,c	Fructose and mannose metabolism
Homovanillic acid	26.142	1.666	0.700^a,c	Tyrosine metabolism
Hypoxanthine√	26.825	1.647	0.524^a,c	Purine metabolism
Isocitric acid	27.218	2.324	0.430^a,c	Tricarboxylic acid (TCA) cycle
l-threonic acid^b	21.022	1.563	0.710^a,c	Unknown
Meso-erythritol√	20.168	1.939	0.553^a,c	Unknown
Methylcitric acid	27.483	1.686	0.667^a,c	Unknown
Oxalic acid√	10.164	2.416	0.574^a,c	Glyoxylate and dicarboxylate metabolism
Phenylalanine	22.88	1.575	0.223^b	Phenylalanine metabolism
p-hydroxyphenylacetic acid	23.253	1.691	0.631^b	Phenylalanine metabolism
Pseudo uridine^b	36.746	1.757	0.596^a,c	Pyrimidine metabolism
Sugar (37.638)	37.638	1.83	0.559^a,c	Starch and sucrose metabolism
Uracil√	15.787	1.679	0.415^a,c	Pyrimidine metabolism
Vanillylmandelic acid	28.385	1.616	0.694^a,c	Unknown

^a p < 0.01, ^b p < 0.05, ^cadjusted p < 0.01 and ^dadjusted p < 0.05.

√means the structure of metabolite has been validated by standard compound.