3.3.1. N. nambi (PW1). Extraction of culture liquid of PW1 (2.025 L)
with EtOAc (2.5 L) yielded 4.6 g of crude extract, from which 2.1 g
of yellow crystals of Aurisin A (6) were obtained after crystallization
from EtOAc. The filtrate was evaporated to dryness and the
residue (2.5 g) was then separated over silica gel flash column
chromatography (FCC), eluted with a gradient system of hexane:
EtOAc and EtOAc:MeOH to give 5 fractions, EF1-EF5. Fraction
EF1 was washed with EtOAc to give an additional amount of
compound 6 (2.04 g). Fraction EF4 was separated on silica gel
column chromatography (CC), eluted with an isocratic system of
hexane:EtOAc:MeOH (50:45:5) to give 3 subfractions, EF4.1eEF4.3.
Subfraction EF4.2 was purified by preparative TLC, using EtOAc:
hexane:MeOH (45:50:5) as eluent to give a colorless oil of