GC-MS analysis was conducted using an Agilent 7890 coupled with an Agilent 5975C (Agilent Technologies, Wilmington, DE, USA). The derivatized metabolite sample (1 μL) was injected into the GC-MS at a split ratio of 1:10. ADB-5MS column (length, 30 m; internal diameter, 0.25 mm; and film thickness, 0.25 μm; Agilent technogies) was used for separation in the GC. The flow rate of helium, the carrier gas, was 1.0 mL min̄¹. The oven temperature was initially set at 80 ̊C with holding for 2 min and then ramped to 300 ̊C at a rate of 15 ̊C min̄¹, following which it was held for 10 min. The injection and interface temperatures were 230 ̊C and 280 ̊C, respectively. The temperature of the EI positive ionsource was 230 ̊C, and the mass spectra of metabolites were recorded in the mass range of 50-600 mz̄¹.