Elaeocarpionoside, a megastigmane glucoside from the leaves of elaeocarpus japonicus sieb. et zucc.

Article abstract of DOI:10.1007/s11418-009-0370-4

From a 1-BuOH-soluble fraction of an extract of the leaves of Elaeocarpus japonicus, six megastigmane glucosides (1-6) were isolated. Five were known compounds (2-6), i.e. amelopsisionoside, citroside A, roseoside, alangionoside A and turpinionoside A, respectively. The structure of the new compound, named elaeocarpionoside, was elucidated to be (3R,4R,5S,6S,7E,9R)-megastigman-7-ene-3, 4,9-triol 9-O-β-D-glucopyranoside by spectroscopic analyses and the modified Mosher's method. The Japanese Society of Pharmacognosy and Springer 2009.

Full text of DOI:10.1007/s11418-009-0370-4

J Nat Med (2010) 64:104–108
DOI 10.1007/s11418-009-0370-4
NOTE
Elaeocarpionoside, a megastigmane glucoside from the leaves
of Elaeocarpus japonicus Sieb. et Zucc.
Junko Shitamoto
•
•
Katsuyoshi Matsunami
Takakazu Shinzato
•
Hideaki Otsuka
Yoshio Takeda
•
Received: 3 August 2009 / Accepted: 9 October 2009 / Published online: 12 November 2009
Ó The Japanese Society of Pharmacognosy and Springer 2009
Abstract From a 1-BuOH-soluble fraction of an extract
of the leaves of Elaeocarpus japonicus, six megastigmane
glucosides (1–6) were isolated. Five were known com-
pounds (2–6), i.e. amelopsisionoside, citroside A, roseo-
side, alangionoside A and turpinionoside A, respectively.
The structure of the new compound, named elaeocarpion-
oside, was elucidated to be (3R,4R,5S,6S,7E,9R)-meg-
astigman-7-ene-3,4,9-triol 9-O-b-D-glucopyranoside by
spectroscopic analyses and the modified Mosher’s method.
7–10 m in height and is found in the temperate zone of
Japan, Ryukyu Islands, Taiwan and China [1]. A decoction
of dried trunk bark of E. japonicus is used as a folk med-
icine in the Satsunan Islands for diseases of the kidneys and
duodenum [2]. Since no systematic investigation on the
constituents of E. japonicus has so far been reported, we
investigated the chemical constituents of the title plant
collected in Okinawa.
From a 1-BuOH-soluble fraction of a MeOH extract of
the leaves of E. japonicus, one new megastigmane gluco-
side (1) was isolated together with five known ones (2–6).
The structures of the known compounds were determined
to be amelopsisionoside (2) [3], citroside A (3) [4],
roseoside (4) [5], alanagionoside A (5) [6] and turpinion-
oside A (6) [7] by comparison of their spectroscopic data
with those reported in the literature. This paper deals with
structural elucidation of the new megastigmane glucoside.
Keywords Elaeocarpus japonicus ꢀ Elaeocarpaceae ꢀ
Megastigmane glucoside ꢀ Elaeocarpionoside ꢀ
Modified Mosher’s method
Introduction
Only three species belonging to the Elaeocarpaceae are
known to grow wild in Japan. One of these species,
Elaeocarpus japonicus, is an evergreen tree of about
Results and discussion
Air-dried leaves of E. japonicus were extracted with
MeOH three times and the concentrated MeOH extract was
partitioned between solvents of increasing polarity. The 1-
BuOH-soluble fraction was separated by means of various
chromatographic procedures including column chroma-
tography (CC) on a highly porous synthetic resin (Diaion
HP-20), normal silica gel and reversed-phase octadecyl
silica gel (ODS) CC, droplet counter-current chromatog-
raphy (DCCC) and high-performance liquid chromatogra-
phy (HPLC) to afford six compounds (1–6). The details
and yields are given in the ‘‘Experimental’’ section. The
structure of the new megastigmane glucoside (1) was elu-
cidated on the basis of spectroscopic evidence and struc-
tures of known compounds were identified by comparison
J. Shitamoto ꢀ K. Matsunami ꢀ H. Otsuka (&)
Department of Pharmacognosy,
Graduate School of Biomedical Sciences,
Hiroshima University, 1-2-3 Kasumi, Minami-ku,
Hiroshima 734-8553, Japan
e-mail: hotsuka@hiroshima-u.ac.jp
T. Shinzato
Subtropical Field Science Center, Faculty of Agriculture,
University of the Ryukyus, 1 Senbaru, Nishihara-cho,
Nakagami-gun, Okinawa 903-0213, Japan
Y. Takeda
Faculty of Pharmacy, Yasuda Women’s University,
6-13-1 Yasuhigashi, Asaminami-ku,
Hiroshima 731-0153, Japan
1
23

J Nat Med (2010) 64:104–108
105
OGlc
OH
OH
11
7
O
O
HO
OH
1
2
H
C
4
HMBC
HO
13
HO
1
1
H- H COSY
OH
OH
1
Fig. 2 Key H– H COSY and HMBC correlations of 1
1
Fig. 1 Structure of elaeocarpionoside (1)
of spectroscopic data with those reported in the literature
Fig. 1).
Elaeocarpionoside (1), [a]D -2.9, was obtained as an
(
2
1
amorphous powder and its elemental composition was
determined to be C H O by high-resolution (HR)-elec-
9 34 8
H
OGIc
1
trospray ionization (ESI)–MS. The IR spectrum exhibited
H
H
-
absorption for glycosidic (3369, 1066 and 1039 cm ) and
1
HO
-
1
1
aliphatic (2925 and 1455 cm ) features. In the H-NMR
spectrum, signals for two singlet (dH 0.90 and 0.89) and
two doublet (dH 1.29 and 0.92) methyls, an anomeric
HO
H
H
H
proton (d 4.36, J = 8 Hz), and two olefinic protons in the
H
trans geometry [d 5.53 (dd, J = 15, 7 Hz) and 5.34 (dd,
H
1
3
J = 15, 9 Hz)] were observed. The C-NMR spectrum
displayed six signals assignable to a b-D-glucopyranosyl
moiety, whose absolute configuration was ascertained by
the positive sign of optical rotation value of the glucose,
obtained on enzymatic hydrolysis. The remaining 13 sig-
nals comprised those of four methyls, one methylene, three
methines with oxygen substituents and two without oxygen
Fig. 3 PS-NOESY correlations of 1
3
2
substituents, and one quaternary sp and two sp carbons.
1
method was applied to the aglycone (1a) [10]. The results
shown in Fig. 4 clearly demonstrate that 1a has the
3R,4R,5S,6S,9R configuration (Fig. 4). Therefore, the
structure of elaeocarpionoside (1) was elucidated to be
(3R,4R,5S,6S,7E,9R)-megastigman-7-ene-3,4,9-triol 9-O-
b-D-glucopyranoside, as shown in Fig. 1.
1
The H– H COSY spectrum showed chains of correlation
from H -2 through H -10 and H-5 to H -13. With the aid of
2
3
3
the HSQC spectrum, the structure of elaeocarpionoside was
assigned as the b-D-glucopyranoside of 3,4,9-trihydrox-
ymegastigman-7-ene. The position of the sugar linkage was
determined to be the hydroxyl group at the 9-position,
since a significant HMBC correlation peak was observed
0
between H-1 (d 4.36) and C-9 (d 77.7) (Fig. 2). Judging
Experimental
H
C
1
from the coupling constants in the H-NMR spectrum, H-3
and H-4 were in a diaxial relationship, and then H-4 and H-
General
5
, and H-5 and H-6 were also in the diaxial relationships.
This was substantiated by correlations (H-2ax and H-4ax,
H-3ax and H-5ax, and H-4ax and H-6ax) observed in the
phase-sensitive (PS)-NEOSY spectrum (Fig. 3). The
absolute configuration at the 9-position was expected to be
Optical rotations were measured on a JASCO P-1030
polarimeter. An IR spectrum was measured on a Horiba
1
13
FT-710 spectrophotometer. H- and C-NMR spectra were
recorded on a JEOL JNM a-400 spectrometer at 400 and
100 MHz, respectively, with tetramethylsilane as an
internal standard. Positive-ion HR-MS were measured with
an Applied Biosystem QSTAR XL system ESI (Nano
Spray)–MS.
1
3
R, judging from the C-NMR chemical shifts of related
compounds [8, 9]. To confirm the absolute configuration of
the 9-position and to establish that in the ring system, 1 was
enzymatically hydrolyzed, and the modified Mosher’s
123

1
06
J Nat Med (2010) 64:104–108
OMTPA
extracted with 1-BuOH (6 l) to give a 1-BuOH-soluble
fraction (1.54 kg), and the remaining water layer was
concentrated to afford 1.66 kg of a water-soluble fraction.
A portion (283 g) of the 1-BuOH-soluble fraction was
subjected to CC on a Diaion HP-20 column (U = 50 mm,
–
0.130
+
+
0.047
0.065
–
0.102
+0.047
L = 50 cm) using H O–MeOH [(4:1, 2 l), (2:3, 8 l), (3:2,
2
MTPAO
8
l) and (1:4, 8 l)] and MeOH (8 l), 1-l fractions being
collected. The residue (117 g in fractions 6–9) from the
0–40% MeOH eluent was subjected to silica gel (1.80 kg;
U = 9 cm, L = 60 cm) CC, with CHCl –MeOH [(9:1,
–
0.068
OH
Fig. 4 Results of the modified Mosher’s method (Dd
2
S
–d
R
)
3
6
l), (17:3, 8 l) and (4:1, 8 l)] and CHCl –MeOH–H O
3 2
A highly porous synthetic resin (Diaion HP-20) was
purchased from Mitsubishi Kagaku (Tokyo, Japan). Silica
gel CC and reversed-phase (ODS gel) open CC were per-
formed on silica gel 60 (Merck, Darmstadt, Germany) and
Cosmosil 75C -OPN (Nacalai Tesque, Kyoto, Japan)
[(35:15:2, 8 l) and (25:25:4, 8 l)], 400-ml fractions being
collected. An aliquot (3.5 g) of the residue (12.8 g) in
fractions 59–66 was separated by ODS CC and the residue
(134 mg) in fractions 84–90 was further separated by
DCCC to give the residue (19.3 mg) in fractions 30–46,
1
8
[
(
U = 50 mm, L = 25 cm; linear gradient: MeOH–H O
1:9, 1 l) ? (1:1, 1 l), fractions of 10 g being collected],
which was finally purified by HPLC (MeOH–H O, 1.3:2.7)
2
2
to afford 2.7 mg of 1 from the peak at 12 min. The residue
(188 mg) in fractions 91–102 obtained on ODS CC was
again separated by silica gel CC (35 g; U = 2 cm,
L = 23 cm) with CHCl –MeOH–H O (15:6:1), 2.5-ml
respectively. The DCCC (Tokyo Rikakikai, Tokyo, Japan)
was equipped with 500 glass columns (U = 2 mm,
L = 40 cm), and the lower and upper layers of a solvent
mixture of CHCl –MeOH–H O–n-PrOH (9:12:8:2) were
3
2
3
2
fractions being collected, to give the residue (49.6 mg) in
fractions 30–69, which was then purified by HPLC
used as the stationary and mobile phases, respectively.
Five-gram fractions were collected and numbered accord-
ing to their order of elution with the mobile phase. HPLC
was performed on an ODS column (Inertsil; GL Science,
Tokyo, Japan; U = 6 mm, L = 25 cm), and the eluate was
monitored with a UV detector at 254 nm and a refractive
index monitor.
(MeOH–H O, 7:13) to yield 2.3 mg of 6 from the peak at
2
9 min.
The residue (56.7 g) in fractions 10–16 obtained on
Diaion HP-20 CC was subjected to silica gel CC (1.3 kg;
U = 8 cm, L = 22 cm) eluting with CHCl3 (4 l) and
CHCl –MeOH [(99:1, 8 l), (97:3, 8 l), (19:1, 8 l), (37:3,
3
Emulsin was purchased from Tokyo Chemical Indus-
tries Co., Ltd (Tokyo, Japan), and crude hesperidinase was
a gift from Tokyo Tanabe Pharmaceutical Co., Ltd (Tokyo,
Japan). The (R)- and (S)-a-methoxy-a-trifluoromethyl-
phenylacetic acids (MTPA) were the products of Wako
Pure Chemical Industry Co., Ltd (Tokyo, Japan).
8 l), (9:1, 8 l), (35:5, 8 l), (17:3, 8 l), (33:7, 8 l), (4:1, 8 l),
(3:1, 8 l) and (7:3, 8 l)], 500-ml fractions being collected.
The residue (2.12 g) in fractions 81–100 was separated by
ODS CC and 45.5 mg of 4 was isolated from the residue
(234 mg) in fractions 68–78, followed by DCCC (in frac-
tions 43–51). The residue (2.15 g) in fractions 101–105
was separated by ODS and the residue (430 mg) in frac-
tions 66–78 was again separated by DCCC to give two
residues (79.8 and 112 mg) in fractions 40–45 and 55–65,
respectively. The former was then purified by HPLC
Plant material
Leaves of E. japonicus were collected in Okinawa, Japan,
in July 2001, and a voucher specimen was deposited in the
Herbarium of Pharmaceutical Sciences, Graduate School of
Biomedical Sciences, Hiroshima University (01-EJ-Oki-
nawa-0705).
(MeOH–H O, 9:31) to give 8.9 mg of 5 from the peak at
2
38 min. The latter was found to be a pure compound, 3.
The residue (243 mg) in fractions 79–87 was purified by
DCCC to give 43.4 mg of 2 in fractions 40–49.
Extraction and isolation
Elaeocarpionoside (1)
2
D
1
Dried leaves of E. japonicus (16.4 kg) were extracted three
times with MeOH (45 l) at 25°C for 1 week and then
concentrated to 6 l in vacuo. The extract was washed with
n-hexane (6 l, 194 g) and then the MeOH layer was con-
centrated to a gummy mass. The latter was suspended in
water (6 l) and then extracted with EtOAc (6 l) to give
Amorphous powder, [a] -2.9 (c 0.17, MeOH). IR m
max
1
-
(film) cm : 3369, 2925, 1650, 1455, 1370, 1066, 1039. H
1
NMR (CD OD, 400 MHz) d: 5.53 (1H, dd, J = 15, 7 Hz,
3
H-8), 5.34 (1H, dd, J = 15, 9 Hz, H-7), 4.36 (1H, d,
0
J = 8 Hz, H-1 ), 4.36 (1H, dq, J = 7, 6 Hz, H-9), 3.80
0
(1H, dd, J = 12, 2 Hz, H-6 a), 3.68 (1H, dd, J = 12, 5 Hz,
0
4
61 g of an EtOAc-soluble fraction. The aqueous layer was
H-6 b), 3.54 (1H, ddd, J = 12, 9, 5 Hz, H-3), 3.34 (2H, m,
1
23

J Nat Med (2010) 64:104–108
107
0
0
0
H-3 and 4 ), 3.20 (1H, ddd, J = 10, 5, 2 Hz, H-5 ), 3.18
0
Na SO and then evaporated under reduced pressure. The
4
2
(
1H, dd, J = 9, 8 Hz, H-2 ), 2.82 (1H, dd, J = 9, 9 Hz, H-
residue was purified by preparative TLC [silica gel (0.25-
mm thickness), being applied for 18 cm and developed
with CHCl –(CH ) CO (19:1) for 9 cm; the band at R 0.6
4
9
1
1
), 1.67 (1H, dd, J = 12, 5 Hz, H-2a), 1.50 (1H, dd, J = 9,
Hz, H-6), 1.45 (1H, m, H-5), 1.29 (3H, d, J = 6 Hz, H3-
0), 1.23 (1H, dd, J = 12, 12 Hz, H-2b), 0.92 (3H, s, H -
3
3 2
f
was scraped off and eluted with CHCl –MeOH (9:1)] to
3
3
1
3
3), 0.90 (3H, s, H -11), 0.89 (3H, s, H -12). C NMR
3
afford an ester, 1b (0.3 mg, 26%). Through a similar pro-
cedure, 1c (0.3 mg, 26%) was prepared from 1a (0.4 mg)
using (S)-MTPA (24 mg), EDC (16 mg) and 4-DMAP
(10 mg).
3
(
CD OD, 100 MHz) d: 136.7 (C-8), 132.6 (C-7), 102.4 (C-
3
0
0
0
1
), 82.2 (C-4), 78.2 (C-3 ), 77.9 (C-5 ), 77.7 (C-9), 75.5
0
0
0
(
C-2 ), 72.4 (C-3), 71.5 (C-4 ), 62.7 (C-6 ), 57.4 (C-6), 48.6
C-2), 38.8 (C-5), 35.4 (C-1), 31.8 (C-12), 21.8 (C-11),
(
(3R,4R,5S,6S,7E,9R)-Megastigman-7-ene-3,4,9-triol
3,9-di-O-(R)-MTPA ester (1b): an amorphous powder; H-
1
2
1.4 (C-10), 17.4 (C-13). HR-ESI–MS (positive-ion mode)
?
m/z: 413.2150 [M ? Na]
13.2145).
(calcd for C H O Na:
9
NMR (CDCl , 400 MHz) d: 7.55–7.51 (4H, m, aromatic
1
34
8
3
4
protons), 7.41–7.36 (6H, m, aromatic protons), 5.49 (1H,
m, H-7), 5.47 (1H, m, H-8), 5.06 (1H, ddd, J = 12, 9,
5 Hz, H-3), 3.55 (3H, br s, –OCH ), 3.52 (3H, br s, –
Enzymatic hydrolysis of elaeocarpionoside (1)
3
OCH ), 3.20 (1H, dtt, J = 9, 5, 5 Hz, H-4), 1.84 (1H, dd,
3
Elaeocarpionoside (1) (2.7 mg) in 2 ml of H O was
2
J = 12, 5 Hz, H-2a), 1.90 (1H, m, H-5), 1.50 (1H, dd,
J = 9, 9 Hz, H-6), 1.37 (3H, d, J = 6 Hz, H -10), 1.33
hydrolyzed with emulsin (4.0 mg) and crude hesperidinase
3
(
4.0 mg) for 18 h at 37°C. The reaction mixture was
(1H, dd, J = 12, 12 Hz, H-2b), 0.96 (3H, s, H -11), 0.94
3
evaporated to dryness, and then the methanolic solution
was absorbed on silica gel and subjected to CC (6 g,
U = 10 mm, L = 17 cm) with CHCl (50 ml) and CHCl –
(3H, d, J = 6 Hz, H -13), 0.82 (3H, s, H -12); HR-ESI–
3
3
?
MS (positive-ion mode) m/z: 683.2415 [M ? Na] (calcd
for C H O F Na: 683.2413).
33 38 7 6
3
3
MeOH [(19:1, 50 ml), (9:1, 50 ml) and (7:3, 150 ml)], 5-
(3R,4R,5R,6S,7E,9R)-Megastigman-7-ene-3,4,9-triol
3,9-di-O-(S)-MTPA ester (1c): an amorphous powder, H-
1
ml fractions being collected. The aglycone (1a) (1.2 mg,
7
6%) and D-glucose (1.1 mg, 85%) were recovered in
NMR (CDCl , 400 MHz) d: 7.55–7.50 (4H, m, aromatic
3
fractions 23–28 and 43–52, respectively. Aglycone (1a):
2
protons), 7.42–7.36 (6H, m, aromatic protons), 5.37 (1H,
4
1
amorphous powder, [a]D ?10.0° (c 0.08, MeOH). H-
m, H-8), 5.36 (1H, m, H-7), 5.50 (1H, ddd, J = 12, 9,
5 Hz, H-3), 3.57 (3H, q, J = 1 Hz, –OCH ), 3.56 (3H, q,
NMR (CD OD, 400 MHz) d: 5.45 (1H, dd, J = 15, 6 Hz,
3
3
H-8), 5.29 (1H, dd, J = 15, 9 Hz, H-7), 4.23 (1H, qd,
J = 6, 1 Hz, H-9), 3.53 (1H, ddd, J = 12, 9, 5 Hz, H-3),
J = 1 Hz, –OCH ), 3.18 (1H, ddd, J = 9, 5, 5 Hz, H-4),
3
1.90 (1H, dd, J = 12, 5 Hz, H-2a), 1.78 (1H, m, H-5), 1.47
(1H, dd, J = 9, 9 Hz, H-6), 1.42 (3H, d, J = 6 Hz, H -10),
2
5
.82 (1H, dd, J = 9, 9 Hz, H-4), 1.67 (1H, dd, J = 12,
Hz, H-2a), 1.46 (1H, dd, J = 9, 9 Hz, H-6), 1.42 (1H, m,
3
1.37 (1H, dd, J = 12, 12 Hz, H-2b), 0.93 (3H, s, H -11),
3
H-5), 1.23 (3H, d, J = 6 Hz, H -10), 1.21 (1H, dd, J = 12,
3
0.89 (3H, d, J = 6 Hz, H -13), 0.81 (3H, s, H -12); HR-
3
3
?
1
2 Hz, H-2b), 0.94 (3H, d, J = 6 Hz, H -13), 0.90 (3H, s,
3
ESI–MS (positive-ion mode) m/z: 683.2421 [M ? Na]
(calcd for C H O F Na: 683.2413).
1
H -11), 0.89 (3H, s, H -12); C NMR (CD OD, 100 MHz)
3
3
3
3
33 38 7 6
d: 138.8 (C-8), 130.7 (C-7), 82.3 (C-4), 72.4 (C-3), 69.3
Acknowledgments The authors are grateful for access to the
superconducting NMR instrument and the HR-ESI–MS at the Ana-
lytical Center of Molecular Medicine and the Analysis Center of Life
Science, respectively, of the Graduate School of Biomedical Sciences,
Hiroshima University. This work was supported in part by Grants-in-
Aid from the Ministry of Education, Science, Sports, Culture and
Technology of Japan, and the Japan Society for the Promotion of
Science. Thanks are also due to the Astellas Foundation for Research
on Medicinal Resources and the Takeda Science Foundation for the
financial support.
(
C-9), 57.3 (C-6), 48.6 (C-2), 38.8 (C-5), 35.1 (C-1), 31.5
(
C-12), 24.1 (C-10), 21.8 (C-11), 17.3 (C-13). HR-ESI–MS
?
positive-ion mode) m/z: 251.1620 [M ? Na] (calcd for
(
2
5
C H O Na: 251.1617). D-Glucose: [a]
(
?28.1°
1
3
24
3
D
c = 0.07, H O, 24 h after being dissolved in the solvent).
2
Preparation of (R)- and (S)-MPTA esters
A solution of 1a (0.4 mg) in 1 ml of anhydrous CH Cl
2
2
was reacted with (R)-MTPA (25 mg) in the presence of 1-
ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochlo-
ride (EDC) (15 mg) and N,N-dimethyl-4-aminopyridine (4-
DMAP) (12 mg), and then the mixture was occasionally
stirred at 25°C for 3 h. After the addition of 1 ml of
CH Cl , the solution was washed successively with H O
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