The essential oil was analysed using a Shimadzu (QP2010) gas chromatograph mass
spectrometer (Tokyo, Japan), with AOC-20i auto-sampler coupled, and a DB-5MS capillary column, (30 m x 0.25 mm i.d., 0.25μm). The initial temperature of column was 70°C held for
4 min and was programmed to 230°C at 4°C/min, then held for 15 min at 230°C; the sample
injection volume was 1μl in GC grade dichloromethane (DCM). Helium was used as carrier
gas at a flow rate of 1.1ml/min on split mode (1:50).