Table 4. Comparison of differential metabolites identified in the present study with other published reports.

Metabolites	Present study	Qiu 14	Nishiumi 15	Tan 16	Cross 17	Zamani 18	Uchiyama 19	Long 20	Nishiumi 21
Hypoxanthine							√	√
Xanthine					√			√
Methionine		√	√	√	√			√	√
Tyrosine		√	√	√	√			√	√
Uric acid							√		√
Acetylcarnitine				√
LysoPE				√
LysoPC				√
Citric acid				√		√	√
Pipecolic acid							√
5-oxoproline								√