Biology Reference
In-Depth Information
Type I
:
gallotannins (galloyl group,
e.g.
, 1,2,3,4,6-penta-
O
-galloyl-β-
D
-
glucose,
i.e.
, PGG)
Type II
: ellagitannins (HHDP group,
e.g.
, pedunculagin)
Type III
: dehydroellagitannins (DHHDP group,
e.g.
, geraniin)
Type IV
: oxidized ellagitannins [chebuloyl group,
e.g.
, chebulagic acid,
geraniinic acids A and B, phyllanthusiins A-C, repandusinic acid,
heterophylliin E]
In addition to these oxidative transformations, various additional
transformations occur in plants, yielding monomers that can be classified
into types I+ to IV+:
Type I+
:
C
-glycosidic gallotannins (3,4,11-tri-
O
-galloylbergenin)
Type II+
:
C
-glycosidic ellagitannins,
e.g.
, casuarinin; complex tannins,
