Clarus 680 system

GC–MS analyses of leaf and rhizome extracts were carried out using the Perkin-Elmer Clarus 680 system (Perkin-Elmer, Inc. U.S.A) equipped with a fused silica column, packed with Elite-5MS) capillary column (30 m in length × 250 μm in diameter × 0.25 μm in thickness). Pure helium gas (99.99%) was used as the carrier gas at a constant flow rate of 1 mL/min. For GC–MS spectral detection, an electron ionization energy method was adopted with high ionization energy of 70 eV (electron Volts) with 0.2 s of scan time and fragments ranging from 40 to 600 m/z. The injection quantity of 1 μL was used (split ratio 10:1), and the injector temperature was maintained at 250 °C (constant). The column oven temperature was set at 50 °C for 3 min, raised at 10 °C per min up to 280 °C, and final temperature was increased to 300 °C for 10 min. The contents of phytochemicals present in the test samples were identified based on comparison of their retention time (min), peak area, peak height and mass spectral patterns with those spectral database of authentic compounds stored in the National Institute of Standards and Technology (NIST) library⁶⁰ .

The EEPO was analyzed using GC-MS for the identification of various phytochemicals. The analysis was carried out using the Perkin-Elmer Clarus 680 system (Perkin-Elmer, Inc., Shelton, CT, USA) equipped with a fused silica column, packed with an Elite-5MS capillary column (30 m in length × 250 μm in diameter × 0.25 μm in thickness). Pure helium gas (99.99%) was used as the carrier gas at a constant flow rate of 1 mL/min. For GC-MS spectral detection, an electron ionization energy method was adopted with a high ionization energy of 70 eV (electron Volts), 0.2 s scan time and fragments ranging from 40 to 600 m/z. An injection quantity of 1 μL was used (split ratio 10:1), and the injector temperature was maintained at 250 °C (constant). The column oven temperature was set at 50 °C for 3 min, then raised at 10 °C per min up to 280 °C, and the final temperature was increased to 300 °C for a period of 10 min. The contents of phytochemicals present in the test samples were identified based on comparison of their retention time (min), peak area, peak height and mass spectral patterns with those spectral databases of authentic compounds stored in the National Institute of Standards and Technology (NIST) library.