AMDIS software (NIST, v2.69, Gaithersburg, MD, USA) coupled with MSD Chemstation software (Agilent Technologies, G1701 EAE.02.00.493, USA) was used for the qualitative and quantitative analysis of mass spectrometry data. MSD software was used to integrate the peak areas. Each peak was qualitatively analyzed in the chromatograms. The spectral libraries used mainly contained data from NIST 2005 and Wiley. All peak areas were normalized for further data processing and imported into Expander (version 6.0) software for cluster analysis. According to a method reported earlier , metabolite data displaying significant changes were imported into MetaboAnalyst3.0 for enrichment analysis and pathway analysis. Pathways with an impact value >0.2 were considered to be significantly affected.