After a solvent delay for 6 min, initial GC oven temperature was set at 60◦C; after injection for 1 min, the GC oven temperature was raised to 280◦C with 15◦C/min, and held at 280◦C for 15 min finally. The injection temperature was set to 280◦C and ion source temperature was adjusted to 230◦C. Helium was used as the carrier gas with a constant flow rate set at 1 mL/min. The measurement was performed with electron impact ionization (70 eV) in the full scan mode (m/z from 30 to 600). Metabolite Data Processing and Analysis Peak finding, peak integration, and retention time correction were performed with the Agilent MSD Productivity Chemstation software. The metabolites were identified based on retention time index specific masses, via comparing with reference spectra in mass spectral libraries (NIST 2005, Wiley 7.0).