Ten grams of n-hexane
extract was subjected to column chromatography (CC; 5 cm
of diameter) on silica gel (40–63 µm) and eluted (100 mL
for each elution) with a gradient system of n-hexane–EtOAc
(10:0 to 0:10, v/v) and EtOAc–MeOH (10:0 to 0:10, v/v) to
yield 20 mL of each fraction. Each fraction was checked by
thin-layer chromatography, and fractions with same spots
were combined to afford 19 fractions (F1–F19)