Table 4.

KEGG pathways representing the differentially expressed compounds in asthma patients compared with healthy control using UHPLC-QTOF-MS in negative ion mode

Pathway	Compounds
Metabolic pathways-Homo sapiens (human)	Phosphoenolpyruvate, myo-Inositol, 3-Methyl-2-oxobutanoic acid, Adenine, Phenylpyruvate, Thymidine, Hexadecanoic acid, Indole, N-Acetyl-L-glutamate, Urocanate, 2-Methylprop-2-enoyl-CoA
Biosynthesis of amino acids-Homo sapiens (human)	Phosphoenolpyruvate, 3-Methyl-2-oxobutanoic acid, Phenylpyruvate, N-Acetyl-L-glutamate
2-Oxocarboxylic acid metabolism-Homo sapiens (human)	3-Methyl-2-oxobutanoic acid, Phenylpyruvate, N-Acetyl-L-glutamate
Phenylalanine, tyrosine and tryptophan biosynthesis-Homo sapiens (human)	Phosphoenolpyruvate, Phenylpyruvate, Indole
Valine, leucine and isoleucine degradation-Homo sapiens (human)	3-Methyl-2-oxobutanoic acid, 2-Methylprop-2-enoyl-CoA