Biology Reference
In-Depth Information
[
14
C]pentagalloylglucopyranose (
3
, see
Fig. 3.11, panel A). Time-course
experiments revealed that a first product,
i.e.
, tellimagrandin II (
4
), was
rapidly converted to a second metabolite that was later identified as the
dimeric ellagitannin cornusiin E (
22
, see Fig. 3.11, panel B). Subsequent
enzyme studies employing
4
as substrate showed that this compound was
indeed specifically oxidized into
22
(Fig. 3.12, Niemetz
et al.
, 2003).
Fig. 3.9
In vitro
oxidation of [
U
-
14
C]pentagalloylglucopyranose (
3
) to ellagitannins with
cell-free extracts from
Tellima grandiflora
leaves.
A
: Reversed phase (RP-18) HPLC of
reaction products. (―) complete enzyme assay; (····) control with acid-denatured enzyme.
B
: RP-18 HPLC of hydrolysis products of marked (⇓) main product in
A
, yielding
[
14
C]glucose, [
14
C]gallic acid (
1
) and [
14
C]ellagic acid (
6
) as degradation products.
Radioactivity was monitored by fractionation of eluates and liquid-scintillation counting.
