New ellagitannin and galloyl esters of phenolic glycosides from sapwood of Quercus mongolica var. crispula (Japanese oak)

Article abstract of DOI:10.1016/j.phytol.2013.06.004

Two novel glycosides, 4,5-dimethoxy-3-hydroxyphenol 1-O-β-(6′-O- galloyl)-glucopyranoside (1) and (+)-2α-O-galloyl lyoniresinol 3α-O-β-D-xylopyranoside (2), as well as a novel ellagitannin named epiquisqualin B (3), were isolated from sapwood of Quercus mongolica var. crispula along with 19 known phenolic compounds. The structures of the novel compounds were elucidated on the basis of chemical and spectroscopic investigation. Compound 2 is the first example of a lignan galloyl ester, and 3 is the oxidation product of vescalagin, which is the major ellagitannin of this plant.

Full text of DOI:10.1016/j.phytol.2013.06.004

Phytochemistry Letters 6 (2013) 486–490
Contents lists available at SciVerse ScienceDirect
Phytochemistry Letters
journal homepage: www.elsevier.com/locate/phytol
New ellagitannin and galloyl esters of phenolic glycosides from
sapwood of Quercus mongolica var. crispula (Japanese oak)
Mohamed Omar a,b, Yosuke Matsuo a, Hajime Maeda c, Yoshinori Saito a, Takashi Tanaka a,
*
a Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-Machi, Nagasaki 852-8521, Japan
b Faculty of Pharmacy, Assuit Branch, Al-Azhar University, Assuit 71524, Egypt
c Nagasaki Agricultural and Forestry Technical Development Center, 3118 Kaidzu, Isahaya, Nagasaki 854-0063, Japan
A R T I C L E I N F O
A B S T R A C T
b
-(60-O-galloyl)-glucopyranoside (1) and
Article history:
Two novel glycosides, 4,5-dimethoxy-3-hydroxyphenol 1-O-
Received 17 March 2013
Received in revised form 30 May 2013
Accepted 4 June 2013
(+)-2a-O-galloyl lyoniresinol 3a-O-b-D-xylopyranoside (2), as well as a novel ellagitannin named
epiquisqualin B (3), were isolated from sapwood of Quercus mongolica var. crispula along with 19 known
phenolic compounds. The structures of the novel compounds were elucidated on the basis of chemical
and spectroscopic investigation. Compound 2 is the first example of a lignan galloyl ester, and 3 is the
oxidation product of vescalagin, which is the major ellagitannin of this plant.
Available online 21 June 2013
Keywords:
ß 2013 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
Quercus mongolica
Fagaceae
Sapwood
Lignan glycoside
Ellagitannin
Polyphenol
1. Introduction
(Japanese oak) is a deciduous tree distributed in all of the main
Japanese islands; its wood has considerable strength and hardness
Quercus species, commonly known as oak trees, are common
woody plants in the Northern Hemisphere. These trees are an
important material in the architectural and cooperage industries.
Oak wood is divided into heartwood and sapwood. Sapwood is the
outer layer containing living ray parenchymal cells and dead
conductive tissues such as vessels and tracheids. Heartwood is the
inner layer composed of only dead cells, and contains C-glycosidic
and is used in cabinetwork, architecture, and cooperage. The bark
of this species has been investigated in detail (Ishimaru et al., 1987,
1988a); however, no chemical study on the wood constituents has
been conducted. In this paper, we investigated the phenolic
compounds in the Japanese oak sapwood, the wood portion where
the heartwood constituents are biosynthesized.
´
ellagitannins (Herve Du Penhoat et al., 1991a,b; Viriot et al., 1994;
2. Results and discussion
´
Fernandez de Simon et al., 2006) with antibacterial activity (Taguri
et al., 2004). These ellagitannins are responsible for the plant
defense against fungal or bacterial decay and thus for the
durability of the wood. When the tree grows, the living ray
parenchymal cells in the transition area between sapwood and
Sapwood was extracted with 70% aqueous acetone and the
extract was separated by a combination of Sephadex LH-20, Diaion
HP20SS, Chromatorex ODS, and silica gel column chromatography
to afford three new compounds (1–3) along with 19 known
compounds. Based on comparison of the spectral data, the known
compounds were identified as 2-methoxy-4-hydroxyphenol 1-O-
heartwood die through
a programmed process, while the
heartwood constituents are biosynthesized in the cells. The
ellagitannins that remain in the dead cells after heartwood
formation gradually undergo chemical changes such as insolubili-
zation (Peng et al., 1991) and dehydration (Tanaka et al., 1996).
From a phytochemical point of view, the production of these
chemicals and their changes during the long-term storage of wood
are very interesting. Quercus mongolica Fisch. Ex Ledeb var. crispula
b
-(60-O-galloyl) glucopyranoside, 3-methoxy-4-hydroxyphenol 1-
O-
-(60-O-galloyl) glucopyranoside (Saijo et al., 1989), 3,5-
dimethoxy-4-hydroxyphenol 1-O-
-(60-O-galloyl) glucopyrano-
side (Lampire et al., 1998), (2R,3R)-taxifolin 3-O- -glucoside,
(2S,3S)-taxifolin 3-O- -glucoside (Hosoi et al., 2006), peduncula-
b
b
b
b
´
gin (Ishimatsu et al., 1989), vescalagin (5) (Herve Du Penhoat et al.,
1991a), castalagin (Herve´ Du Penhoat et al., 1991a), grandinin
(Nonaka et al., 1989), methyl vescalagin (Yoshida et al., 1991),
vescalagin carboxylic acid (Ishimaru et al., 1988b), dehydrocas-
* Corresponding author. Tel.: +81 95 819 2432; fax: +81 95 819 2477.
E-mail address: t-tanaka@nagasaki-u.ac.jp (T. Tanaka).
´
talagin (Glabasnia and Hofmann, 2007), roburin A (Herve Du
1874-3900/$ – see front matter ß 2013 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.phytol.2013.06.004

M. Omar et al. / Phytochemistry Letters 6 (2013) 486–490
487
Fig. 1. Structures of novel compounds 1–3 and quisqualin B (4).
carbons [dC 105.1 (C-10), 74.5 (C-20), 77.6 (C-30), 69.9 (C-40), and
66.4 (C-50)] were ascribable to a pentosyl moiety. Comparison of
these carbon signals with the values in the literature (Dad et al.,
´
Penhoat et al., 1991a), roburin B, roburin D, roburin E (Herve Du
Penhoat et al., 1991b), flavogallonic acid dilactone (Hirano et al.,
2003), ellagic acid, and gallic acid.
Compound 1 was isolated as a yellow amorphous powder and
1989) revealed that 2 was a galloyl ester of lyoniresinol 3
a-O-b-D-
exhibited
a
dark blue coloration after reaction with FeCl3,
xylopyranoside. The -xylose moiety was further confirmed by
D
suggesting the presence of a pyrogallol ring in the molecule. The
[M+H]+ peak at m/z 485.1304 in the HR-FAB-MS indicated that the
molecular formula was C21H24O13 (calcd. for C21H25O13, 485.1295).
The 1H and 13C NMR spectra showed the presence of a galloyl group
and a sugar moiety. The large coupling constants of the anomeric
acid hydrolysis and subsequent HPLC analysis of the thiocarba-
moyl-thiazolidine derivative of the sugar moiety (Tanaka et al.,
2007). The hydrolysis also yielded gallic acid, confirming presence
of the galloyl group. The 1H–1H COSY correlations (Fig. 2) revealed
allylic couplings of benzylic protons (H-1 and H-4) with aromatic
protons in addition to vicinal couplings between aliphatic protons.
The correlations confirmed the assignment of the signal of the H-
2a methylene proton, which resonated at a lower field [dH 4.35 (dd,
J = 4.3, 10.9 Hz) and 4.25 (dd, J = 6.8, 10.9 Hz)] compared with
those of lyoniresinol (dH 3.5–3.6). This observation indicated that
proton at dH 4.88 (1H, d, J = 7.8 Hz) and pyranose ring protons at dH
3.43 (dd, J = 7.8, 8.8 Hz, H-2), 3.52 (t, J = 8.8 Hz, H-4), and 3.55 (t,
J = 8.8 Hz, H-3) indicated that this sugar was glucopyranose. This
was supported by 13C NMR signals at
d
C 101.9 (glc-1), 77.1 (glc-3),
74.7 (glc-5), 74.1 (glc-2), 70.7 (glc-4), and 65.4 (glc-6). The coupling
constant of the anomeric proton (8 Hz) and the chemical shift of
the galloyl group was located at the C-2
low field shift of the aglycone C-3 carbon signal (
compared with that of lyoniresinol ( C 64.2) (Li and Seeram, 2010)
a
hydroxyl group. The large
the anomeric carbon showed the
glucose moiety. In addition, low field shifts of the glucose C-6
methylene proton signals at H 4.35 (dd, J = 5.5, 11.9 Hz) and 4.56
b
-glycosidic linkage of the
a
dC 71.1, Dd 6.9)
d
d
confirmed the location of the xylose. The aglycone moiety was
determined to be a (+)-form by comparison of the CD data with
reported data (Ohashi et al., 1994). Thus, compound 2 was
(dd, J = 1.9, 11.9 Hz) confirmed the location of a galloyl group at
this position. As for the aglycone, the appearance of signals
corresponding to two non-equivalent methoxyl groups [dH 3.62
determined to be (+)-2a-O-galloyl lyoniresinol 3a-O-b-D-xylo-
(3H, s) and 3.65 (3H, s);
coupled aromatic protons [
d
C 56.0 and 60. 7] and two mutually meta-
H 6.21 and 6.25 (each 1H, d, J = 2.7 Hz)]
pyranoside (Fig. 1).
Compound 3 was also positive to FeCl3 (dark blue), and the
molecular formula C40H26O25 was deduced from the [M+H]+ peak
d
suggested that the aglycone moiety was a benzene with an
asymmetrical substitution system. Finally, the substitution pattern
was confirmed by NOESY spectrum, in which the sugar anomeric
proton signal showed NOE with both of the aromatic methine
protons. This observation and the asymmetric structure of the
aglycone indicated that the glucosyl residue was attached to the C-
1 hydroxyl group of 1,3-dihydroxy-4,5-dimethoxybenzene. The
NMR chemical shifts of the aglycone were consistent with those of
a desgalloyl form of 1 (Takara et al., 2002). Accordingly, compound
at m/z 907.0824 in the HR-FAB-MS (calcd. for C40H27O25
,
907.0841). The 1H and 13C NMR spectra were related to those of
vescalagin (5), showing the signals arising from hexahydroxydi-
phenoyl (HHDP) esters, five ester carbon signals, including those of
the HHDP group, and a glucose with open-chain form. In particular,
the 13C NMR chemical shifts and the 1H NMR coupling constants of
the glucose moiety [
4), 71.2 (C-5); J1,2 = 2.0 Hz,
d
C 65.5, 65.6 (C-1, 6), 78.1 (C-2), 68.1, 68.3 (C-3,
2,3 < 2 Hz, J3,4 = 6.5 Hz, and
J
1 was characterized as 1
b
-(3-hydroxy-4,5-dimethoxyphenyl)-O-
J4,5 = 8.0 Hz] were very similar to those of 5, suggesting a similar
configuration and conformation of the glucose moiety. However,
the 13C NMR spectrum indicated that there were only four
(60-O-galloyl)-glucopyranoside (Fig. 1).
Compound 2 was obtained as a yellow amorphous powder and
the dark blue coloration obtained by reaction with FeCl3 on the TLC
plate was similar to that of 1. The molecular formula was
determined to be C34H40O16 by HR-FAB-MS (m/z 727.2199
[M+Na]+, calcd. for C34H40O16Na, 727.2214). The 13C NMR
spectrum showed three sets of signals attributable to 3,4,5-
trioxygenated benzene rings, one of which was identical to those of
the galloyl group. In addition, the appearance of signals
corresponding to three methine carbons [dC 37.2 (C-2), 42.7 (C-
4) and 46.5 (C-3)], three methylene carbons including two
oxygenated ones [dC 33.7 (C-1), 67.7 (C-2
a
) and 70.8 (C-3
a)],
and four methoxyl groups including two equivalent ones [
d
C 59.3,
56.3, and 56.8 (2C)] suggested that 2 had a phenyl tetrahydro-
naphthalene-type lignan moiety. The remaining five aliphatic
Fig. 2. 1H–1H COSY correlations (bold lines) of 2.

488
M. Omar et al. / Phytochemistry Letters 6 (2013) 486–490
Fig. 3. Biogenesis of epiquisqualin B (3) from vescalagin (5).
aromatic rings, including those of the HHDP groups. Instead,
signals due to an -unsaturated carbonyl group [ C 202.1 (C-4),
137.9 (C-5), and 153.7 (C-1)] accompanied by a methine [ C 45.9
(C-2)] and a methylene [dC 36.3 (C-3)] were observed. These
signals are closely related to those of the cyclopentanone moiety
of quisqualin B (4) (Lin et al., 1997). The difference between 3 and
4 was evidently observed in the chemical shift and coupling
constant of the glucose H-1 (3: dH 4.82, J1,2 = 2.0 Hz, 4: dH 5.70,
J1,2 = 5.0 Hz). In the 13C NMR spectrum, the apparent difference
3.2. Biological material
a
,
b
d
d
Wood of Q. mongolica var. crispula was collected in Hokkaido,
Japan by Suntory Liquors Ltd. in 2009, and the voucher specimen
(MIZUNARA-731) was deposited at the Medicinal Plant Garden of
Graduate School of Biomedical Sciences, Nagasaki University,
Japan.
3.3. Extraction and isolation
was the chemical shift of the glucose C-2 [3: dC 78.1, 4: dC 74.3].
These spectroscopic differences were also observed between 5
and its C-1 epimer, castalagin (Nonaka et al., 1990). The CD
spectrum of 3 was similar to that of 5 (Okuda et al., 1982),
indicating that the biphenyl linkages of 3 had the S-configuration.
Based on these spectroscopic data, 3 was determined to be the C-1
epimer of 4, and was named epiquisqualin B (Fig. 1). This
compound is apparently the oxidation metabolite of 5 and its
proposed biogenesis is shown in Fig. 3.
Like in other oak woods, the major polyphenols of the sapwood
of Q. mongolica var. crispula were vescalagin (5) and castalagin,
which had yields of 0.19% and 0.26%, respectively. Related
ellagitannins, including dimeric ellagitannins and roburins A, B
and D, were also isolated. Other minor constituents isolated in this
study were lignans, simple phenolic glycosides, and dihydro-
Sapwood (2.0 kg) was chipped into small pieces and
extracted five times with 70% acetone in H2O. The plant debris
was further extracted with 100% MeOH (10 L, two times). The
extracts were combined and partitioned with EtOAc to give an
EtOAc extract (45 g) and an aqueous layer. The insoluble
precipitates (17 g) in the aqueous layer were removed by
filtration, and the filtrate was subjected to Sephadex LH-20
column chromatography (10 cm ꢀ 50 cm, 0–100% MeOH in H2O)
to give 14 fractions. Fraction 8 (6.7 g) was separated by Diaion
HP20SS column chromatography with 0–100% MeOH in H2O to
afford 10 subfractions. Subfraction 8-1 (422 mg) was separated
by Chromatorex ODS (0–100% MeOH in H2O) and Sephadex LH-
20 (0–60% MeOH in H2O) column chromatography to yield
grandinin (290 mg) and vescalagin carboxylic acid (35 mg).
Subfraction 8-3 (887 mg) was purified using Sephadex LH-20
(0–100% MeOH in H2O) and Chromatorex ODS (0–60% MeOH in
flavonol glycosides. Isolation of
3 suggested occurrence of
regioselective oxidation of ellagitannins in wood, and it may be
related to metabolism of wood polyphenols, which is still
chemically unclear. Further chemical study on minor ellagitannins
and non-polar compounds is now in progress.
H2O) columns to give compound
3 (51.5 mg), roburin B
(33.5 mg), and roburin E (43 mg). A similar chromatographic
separation of subfraction 8-5 (440 mg), using Sephadex LH-20,
Chromatorex ODS, and Toyopearl HW40F afforded 3,5-
3. Experimental
dimethoxy-4-hydroxyphenol 1-O-
side (110 mg), 3-methoxy-4-hydroxyphenol1-O-
glucopyranoside (29 mg), 2-methoxy-4-hydroxyphenol 1-O-b-
b
-(60-O-galloyl) glucopyrano-
-(60-O-galloyl)
b
3.1. General experimental procedures
(60-O-galloyl) glucopyranoside (5 mg), and 1 (10 mg). Similarly,
subfraction 8-6 (750 mg) and 8-7 (260 mg) yielded (2R,3R)-
1H and 13C NMR spectra were recorded with a JEOL JNM-AL400
spectrometer (Tokyo, Japan), operating at 400 MHz for 1H, and
100 MHz for 13C. MS was recorded on
spectrometer. Column chromatography was performed on Diaion
HP20SS (Mitsubishi Chemical Co., Tokyo, Japan), Sephadex LH-20
taxifolin 3-O-
was separated by silica gel column chromatography with
CHCl3:MeOH:H2O (40:10:1, and 14:6:1, v/v) to yield
b-glucoside (767 mg). Subfraction 8-9 (202 mg)
a JEOL JMS-700 N
2
(13 mg). Fraction 9 (11.9 g) was subjected to Diaion HP-20SS
column chromatography (0–100% MeOH in H2O), and the
subfractions were repeatedly separated using Sephadex LH-20,
Diaion HP-20SS, Chromatorex ODS, and Toyopearl HW40F to
yield vescalagin (5) (3.87 g), methyl vescalagin (375 mg),
(25–100
Chromatorex ODS (100–200 mesh; Fuji Silysia Chemical Ltd.,
Tokyo, Japan) and Toyopearl HW40F (75 m; Tosoh Bioscience
mm; GE Healthcare Bio-Science AB, Uppsala, Sweden),
m
Japan, Tokyo, Japan). TLC was performed on precoated Kieselgel 60
F254 plates (0.2 mm thick; Merck, Darmstadt, Germany) with
roburin A (66 mg), gallic acid (5 mg), (2S,3S)-taxifolin 3-O-b-
toluene:HCO2Et:HCO2H
(1:7:1
and
1:5:2,
v/v/v)
or
glucoside (12 mg), and ellagic acid (10 mg). Similar separation of
fraction 10 (11 g) yielded castalagin (5.10 g) and from fraction
12 (3 g) roburin D (74 mg), pedunculagin (25 mg), flavogallonic
acid dilactone (30 mg), and dehydrocastalagin (7 mg) were
obtained.
CHCl3:MeOH:H2O (7:3:0.5 or 8:2:0.2, v/v/v) as the mobile phases.
Spots were detected by UV illumination (254 nm), and by spraying
with 2% ethanolic FeCl3 and 5% H2SO4 reagents, followed by
heating.

M. Omar et al. / Phytochemistry Letters 6 (2013) 486–490
489
3.4.
b
-(3-Hydroxy-4,5-dimethoxyphenyl)-O-(60-O-galloyl)-
IR
n
max cmꢁ1: 3428, 1733, 1616, 1456, 1328; UV
l
max (MeOH) nm
glucopyranoside (1)
(
e
) 228 (5.59 ꢀ 104); CD (MeOH) lmax
(De) 230 (+83.7), 258
(ꢁ58.6), 284 (+19.9), 325 (ꢁ21.7); 1H NMR (400 MHz, acetone-d6)
Yellow amorphous powder, a2D7 þ 11:2 (c = 0.1, MeOH); MALDI-
TOF-MS m/z: 507 [M+Na]+; HR-FAB-MS: m/z 485.1304 [M+H]+
(calcd. forC21H25O13, 485.1295 [M+H]+,
d
: 6.52 (1H, s, HHDP-6), 6.73 (1H, s, HHDP-60), 2.70 [1H, dd, J = 6.1,
19.0 Hz, cyclopentenone ring (cp)-3], 2.73 (1H, brd, J = 19.0 Hz, cp-
3), 3.86 (1H, d, J = 12.9, Hz, glc-6), 4.05 (overlapped with solvent
signal, cp-2), 4.64 (1H, d, J = 6.5 Hz, glc-3), 4.82 (1H, d, J = 2.0 Hz,
glc-1), 4.88 (1H d, J = 12.9 Hz, glc-6), 4.97 (1H, dd, J = 6.5, 8.0 Hz,
glc-4), 5.09 (1H, br s, glc-2), 5.59 (1H, d, J = 8.0 Hz, glc-5). 13C NMR
D
+0.9 mmu); IR
max (MeOH) nm (
: 7.08 [2H, s, galloyl
n
max cmꢁ1
): 278
:
3397, 2927, 1700, 1616, 1508, 1456; UV
(9.91 ꢀ 102); 1H NMR (400 MHz, acetone-d6)
l
e
d
(G)-2, 6],6.25(1H, d,J = 2.7 Hz, H-2), 6.21(1H,d,J = 2.7 Hz,H-6), 4.88
(1H, d, J = 7.8 Hz, glc-1), 4.56 (1H, dd, J = 1.9, 11.9 Hz, glc-6a), 4.35
(1H, dd, J = 5.5, 11.9 Hz, glc-6b), 3.80(1H,m, glc-5),3.62(3H,s, OMe),
3.65 (3H, s, OMe), 3.55 (1H, t, J = 8.8 Hz, glc-3), 3.52 (1H, t, J = 8.8 Hz,
glc-4), 3.43 (1H, dd, J = 7.8, 8.8 Hz, glc-2). 13C NMR (100 MHz,
(100 MHz, acetone-d6) d: 36.3 (cp-3), 45.9 (cp-2), 65.5, 65.6 (glc-1,
6), 68.1, 68.3 (glc-3, 4), 71.2 (glc-5), 78.1 (glc-2), 107.3, 108.3
(HHDP-6, 60), 115.1, 115.2, 115.7, 116.3 (2C), 118.0 [HHDP-2, 20,
biphenyl moiety (biph) 2, 20, 6, 60], 124.8 (2 C), 126.6 (2 C) (HHDP-
1, 10, biph-1, 10), 134.9, 135.5, 136.9, 137.9 (2C) (HHDP-4, 40, biph-4,
40, cp-5), 144.3, 144.7 (3 C), 145.4 (2C), 145.5, 148.0 (HHDP-3, 30, 5,
50, biph-3, 30, 5, 50), 153.7 (cp-1), 164.8, 164.9, 167.0, 169.4, 170.0
(HHDP-7, 70, biph-7, 70, cyclo-6), 202.1 (cp-4).
acetone-d6) d: 167.2 (G-7), 155.0 (C-1), 154.2 (C-3), 151.2 (C-5),
145.9 (G-3, 5), 139.0 (G-4), 133.8 (C-4), 121.0 (G-1), 109.7 (G-2, 6),
101.9 (glc-1), 98.0 (C-6), 94.2 (C-2), 77.1 (glc-3), 74.7 (glc-5), 74.1
(glc-2), 70.7 (glc-4), 65.4 (glc-6), 56.0 (OMe), 60.7 (OMe).
3.5. (+)-2a-O-Galloyl lyoniresinol 3a-O-b-D-xylopyranoside (2)
Acknowledgements
Yellow amorphous powder, a2D7 þ 15:3 (c = 0.12, MeOH);
MALDI-TOF-MS m/z: 727 [M+Na]+; HR-FAB-MS: m/z 727.2199
The authors thank Mr. K. Inada, Mr. N. Yamaguchi, and Mr. N.
Tsuda (Nagasaki University) for NMR and MS measurements. The
first author (M. Omar) is grateful to the Ministry of Education,
Science, Culture, Sports, Science, and Technology of Japan for the
award of a scholarship.
[M+Na]+ (calcd. for C34H40O16Na, 727.2214,
D
ꢁ1.5 mmu); IR nmax
cmꢁ1: 3410, 2939, 1695, 1616, 1505, 1456; UV lmax (MeOH) nm
(
e
): 277 (1.45 ꢀ 104); CD (MeOH) lmax
De) 221 (ꢁ8.1), 245 (+4.2),
(
271 (+1.0), 285 (ꢁ0.8); 1H NMR (400 MHz, acetone-d6)
d: 2.05 [1H,
m, lyoniresinol (L)-2], 2.18 (1H, m, L-3), 2.76 (2H, m, L-1), 3.44 (1H,
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4.39 (1H, d, J = 6.9 Hz, L-4), 6.47 (2H, s, L-20, 60), 6.59 (1H, s, L-8),
3.30 (3H, s, L-5-OMe), 3.72 (6H, s, L-30, 50-OMe), 3.81 (3H, s, L-7-
OMe), 3.17 (1H, dd, J = 9.8, 11.4 Hz, xyl-5), 3.28 (1H, dd, J = 7.3,
8.7 Hz, xyl-2), 3.36 (1H, t, J = 8.7 Hz, xyl-3), 3.54 (1H, m, xyl-4), 3.79
(1H, dd, J = 8.0, 11.4 Hz, xyl-5), 4.28 (1H, d, J = 7.3 Hz, xyl-1), 7.10
(2H, s, G-2, 6). 13C NMR (100 MHz, acetone-d6)
(L-2), 42.7 (L-4), 46.5 (L-3), 56.3 (L-7-OMe), 56.8 (2C) (L-30, 50-
OMe), 59.3 (L-5-OMe), 66.4 (xyl-5), 67.7 (L-2 ), 69.9 (xyl-4), 70.8
(L-3 ), 74.5 (xyl-2), 77.6 (xyl-3), 105.1 (xyl-1), 107.1 (2 C), 107.2
(L-20, 60, 8), 109.8 (2C) (G-2, 6), 121.9 (G-1), 126.1, 128.7 (L-9, 10),
134.9 (L-40), 138.6, 138.7 (2 C) (G-4, L-6, 10), 146.0 (2C), 147.1,
147.8, 148.6 (2 C) (G-3,5, L-5, 7, 30, 50), 166.8 (G-7).
d: 33.7 (L-1), 37.2
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reduced pressure, dissolved in pyridine (50
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solution (100 L) of o-tolyl isothiocyanate in pyridine (10 mg/mL)
was added to the mixture, and heated at 60 8C for 1 h. The final
solution was analyzed directly by HPLC using a Cosmosil 5 C18 ARII
column (250 ꢀ 4.6 mm i.d., Nacalai Tesque Inc., Kyoto, Japan) and
25% MeCN in 50 mM H3PO4 as the mobile phase, pumped at a flow
rate of 0.8 mL/min. Detection was performed at 250 nm. The tR of
the peak at 20.6 min coincided with that of the derivative prepared
mL) containing L-
m
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907.0824 [M+H]+ (calcd. for C40H27O25, 907.0841,
D
ꢁ1.7 mmu);

490
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