3.3. Extraction and isolation
The air-dried and powdered stem bark (3 kg) was extracted
with MeOH/CH2Cl2 (1:1, 6 L
2, 48 h) at room temperature. After
filtration, the solution was evaporated in vacuum to yield 150.3 g of
crude extract. A portion (140 g) of this extract was subjected to
flash chromatography over silica gel (300 g, 80
5 cm) eluting with
n-hexane/EtOAc in order of increasing polarity to give four