The extract was collected in ethanol in an amber bottle. In order
to improve the collection efficiency, the bottle was placed in an ice
bath during the dynamic extraction stage, which also acted as a
freezing-trap to minimise the loss of volatile compounds as the
sublimation of CO2 decreases the temperature of the collection solvent.
The precipitates in all the connection tube lines were washed
out with ethanol and then mixed with the collected extract in the
amber bottle. The mixture was made up to 10 ml with ethanol, and
1 ml was taken for GC–MS analysis, the rest was put in a rotary
evaporator (model N-1000S-W, EYELA, Tokyo, Japan) to remove
the ethanol solvent, and then the weight of extracts was measured.
Finally, the extraction yield was estimated as follows: