Astronium urundeuva wood contains a large amount of
extracts, which are constituted mainly by proanthocyanidins,
probably of profisetinidin and prorobinetinidin
types.
The milled wood lignin could not be isolated in pure
form even when extracting the milled wood sequentially
with benzene, benzene:ethanol, chloroform, and water before
the final extraction with ketone:water (9:1). Some
contamination by tannins still remains. This suggests a
strong association between lignin and tannins.
The association of lignin and tannins and/or the presence
of profisetinidins and prorobinetinidins could account
for the great resistance of Astronium urundeuva wood
regarding chemical and biological degradation.