3.3. Extraction and isolation
The air-dried and powdered root bark of E. livingstoniana
(1.2 kg) was soaked twice with dichloromethane–methanol (1:1)
for 24 h, at room temperature. The extract was concentrated under
reduced pressure to give a brown residue (79.0 g). About 69 g of the
extract was applied to column chromatography over silica gel 60
and eluted with n-hexane-EtOAc of increasing polarity. A total of
30 fractions of 200 mL each were collected and combined into 4
fractions (RA-RD) on the bases of similar TLC profile. The first
fractions RA was mostly hydrocarbons and was not investigated
further