The completeness of each extraction was detected using TLC on
which no spot was found in the last extract. Each extract was evaporated
to dryness under reduced pressure at 45 ◦C using a rotary
vacuum evaporator to yield a crude extract. Each extraction procedure
was done in triplicate. The crude extract from each extraction
method was accurately weighed (100 mg) and transferred to a
10 ml volumetric flask, dissolved and adjusted to volume with 70%
ethanol, then analyzed for the content of didehydrostemofoline by
the HPLC.