The dried and powdered flowers (2.5 kg) of A. cyanophylla were
extracted with methanol at room temperature for 48 h. The corresponding
extract was obtained after filtration and evaporation
of the solvent under reduced pressure. The obtained methanolic
extract (50 g) was dissolved in water then extracted successively
with CHCl3 and ethyl acetate to yield the corresponding extracts.
The ethyl acetate extract (25 g) was subjected to silica gel
column chromatography eluting with CHCl3/MeOH gradients. Six
main fractions (250 mL × 6) were collected. After evaporation ofthe
solvent in vaccuo, fraction 5 (19 g) was purified by column chromatography
over silica gel using CHCl3/MeOH (8:2) as eluent to
afford 1 (18 g). The extraction yield of compound 1 is 0.72%