Biology Reference
In-Depth Information
paeoniflorin, which is a water-soluble monoterpene glycoside having a
hydrophobic benzoyl group (see structure in Fig. 4.4). These compounds
co-exist in the root of
Paeonia
lactiflora
. Since the presence of sucrose
did not affect the gel formation, it was deduced that the benzoyl group of
paeoniflorin interrupts the self-association of the PGG molecules.
3,0
8
2,0
10, 12
9
1,0
0,0
16, 17
15
-1,0
11
14
18
-2,0
13
19
20
-3,0
21
-4,0
0
1
2
3
4
5
Fig. 4.2 Partition coefficients of ellagitannins.
9
: eugeniin (1);
10
: phillyraeoidin A (1);
11
: corilagin (1);
12
: des-DHHDP-bischofianin (1);
13
: pedunculagin (2);
14
: 1(β)-O-
galloyl pedunculagin (2);
15
: casuarinin (2);
16
: geraniin (2);
17
: bischofianin (2);
18
:
vescalagin (3);
19
: terflavin A (3);
20
: punicalagin (4);
21
: sanguiin H-6 (4). The number
between parentheses represents the number of biphenyl bonds in the molecule.
number of biaryl bonds
In the
1
H-NMR spectrum, when paeoniflorin was added, the
anomeric proton signal and the aromatic singlet attributable to the galloyl
group attached to the anomeric position of pentagalloylglucose (PGG,
8
)
were shifted to the upper field (Tanaka
et al.
, 1997a). As for
paeoniflorin, the signals of the benzoyl moiety were largely shifted to the
upper field, while the shifts of other proton signals were much smaller.
This observation suggested that the benzoyl group of paeoniflorin is
associated with the anomeric position of
8
via some hydrophobic
interactions, which was supported by intermolecular NOE's between the
benzoyl protons of paeoniflorin and the anomeric proton of
8
.
