The fraction eluted with MeOH (17.5 g) was
applied to a silica gel column using solvent systems EtOAc–
MeOH (9:1, 5 L), EtOAc–MeOH–H2O (40:10:1, 5 L) and
EtOAc–MeOH–H2O (70:30:3, 3.5 L) to give ten fractions.
Fraction 6 (2.9 g) was applied to a column of ODS using a
gradient system [40% aqueous MeOH (1 L) to MeOH (1 L)]
to afford six fractions.