Vol. 28, No. 5.
P r in ted in Gr ea t Br ita in .
1989.
1989
P r ess pk.
PHENOLIC GLUCOSIDES FROM THE HEARTWOOD OF
GRA YANA
H
I R O K O
S
H I M O M U R A
,
Y
U T A K A
and
K I YO S H I Y O S H I N A R I
Tokyo College of Pharmacy, 1432-1, Horinouchi, Hachioji, Tokyo 192-03, Japan
Received 3 October 1988)
grayana; Rosaceae; phenolic glucosides; salicin; populine; pruyanaside A, pruyanaside B;
(
Ke y Word
dehydrodicatechin A.
Abstract-Two new phenohc glucosides, pruyanaside A and pruyanaside B, have been isolated from the heartwood of
Prunus grayana. Their structures have been shown by the spectral evidence to be
and
osyloxy-6-hydroxybenzoate.
INTRODUCTION
seven aliphatic acetate groups and no aromatic acetate
group. Alkaline hydrolysis of 6 with 3% sodium
The bark of Prunus grayana Maxim. has been used as a
crude drug for the treatment of coughs in Europe and
America. Several phenylpropanoid glucosides have been
oxide gave 3, together with salicin (6a)
and methyl
(
6a’). From the findings
presented above, 6 was a benzoyl ester of 3. The location
of the benzoyl group in 6 was determined to be the C-6
hydroxy position of one of the two glucose moieties by
isolated from the bark
However, no study on the
chemical constituents of the heartwood has been carried
out. In this paper, we report two new phenolic glucosides,
pruyanaside A and B, in addition to the known com-
pounds, (+)-taxifolin, dehydrodicatechin A,
side A, henryoside, and populine.
comparison of the
NMR spectrum of 6 with that of 3.
The signal easily assignable to the C-6 position of either
glucose moiety of 6 was shifted downfield (665.2) while
the C-5 was shifted
of 3 (C-6, 662.5; C-5,
also supported by the appearance of the deshielded H-6
proton signals in the
attributable to the H-6 methylene protons of either
showed a
(675.7) as compared with those
The above conclusion was
NMR spectrum of 6. The signals
R E SULTS AND DISCUSSION
The heartwood of P. grayana was extracted with glucose moiety (65.26 and 4.92, each
methanol. From the n-butanol-soluble portion of the downfield shift by ca 0.7 ppm as compared with those of 3
methanol extract, compounds 1-7 were obtained by (64.6-4.1, overlapping). In addition, the assignment of
repeated silica gel and Sephadex LH-20 column chro- the proton signals due to glucose moieties and aromatic
matography.
Compounds
rings of 6 were performed by means of
NMR
1
and 2 were identified as (+)-taxifolin decoupling experiment. In the
spectrum of 6,
and dehydrodicatechin A
respectively. Com- correlations were observed between the H-5 proton
were identified as known salicin derivatives, (64.34) of the glucose residue whose H-6 hydroxyl posi-
pounds
virgaureoside A
their spectroscopic data.
Pruyanaside A
henryoside
and populine
tion was esterified with the benzoyl group and an
proton (S5.55) of glucose, and between the H-5
proton (64.10) of the unesterified glucose moiety and
gave a negative
with benzidine reagent. It showed IR absorption another anomeric proton (65.61) were observed. Further-
bands of hydroxy groups (3420 cm-‘), carbonyl groups more, correlations were observed between the anomeric
of esters (1730 and
1605 cm-i). The
and aromatic rings proton (6 5.55) and H-3 (67.64) and between the anomeric
spectra showed proton (65.61) and H-3’ (67.58). Accordingly, 6 is charac-
(
and
signals due to two glucose moieties, two
terized as
aromatic rings, and methylene protons as in 3. In
addition, the presence of a benzoyl group in the molecule
Pruyanaside B
and gave a positive
was indicated by the
.52 (H-4”) 7.39 (H-3” and H-S’)], and
C-7”) 133.3 (C-4”) 130.8 (C-l”),
NMR
(H-2” and H-6”), coloration with benzidine reagent. It showed IR absorp-
7
tion bands of hydroxy groups (3400
carbonyl
(
and C-6”) 128.8 groups of esters (1705 and 1645
and aromatic rings
(
C-3” and C-5”)] spectra. Acetylation of 6 with acetic (1605 cm-‘). The
and
NMR spectra of 7 were
anhydride in pyridine afforded a heptaacetate
electron impact mass spectrum of 6b gave a molecular ion aromatic region. Acetylation of 7 with acetic anhydride in
peak at
966 and a fragment ion peak at m/z 331, pyridine afforded the octaacetate (76) as a
corresponding to the tetraacetyl glucose oxonium ion. amorphous powder. The EIMS of 7b gave a molecular
The
NMR spectrum of 6b exhibited the presence of ion peak at m/z 1024, and a fragment ion peak at m/z 509.
The almost identical to those of 4 and 6 except for the
1
499