Hydro-distillation was employed to extract the volatile oil from
rhizomes. A total of 100 g of chopped rhizome was homogenized
and placed into a 1 L round-bottom flask with 500mL of distilled
water. The preparation was boiled, the steam was passed through
a condenser, and the condensate was collected in a reservoir flask.
The upper layer of the condensate was removed and placed in a
5mL glass bottle. This volatile oil was kept at −20 ◦C until analysis
of the major components.