Identification of sucrose diesters of aryldihydronaphthalene-type lignans from Trigonotis peduncularis and the nature of their fluorescence

Article abstract of DOI:10.1021/np800071r

Phytochemical investigation of Trigonous peduncularis resulted in the isolation of three aryldihydronaphthalene-type lignan sucrose diesters named trigonotins A-C (1-3). These lignans showed a strong yellow-green fluorescence emission under basic conditions. The structures of the new compounds were elucidated by means of spectroscopic methods, and the nature of their fluorescence was examined.

Full text of DOI:10.1021/np800071r

1178
J. Nat. Prod. 2008, 71, 1178–1181
Identification of Sucrose Diesters of Aryldihydronaphthalene-Type Lignans from Trigonotis
peduncularis and the Nature of Their Fluorescence
Hideaki Otsuka,* Hidenori Kuwabara, and Hiromi Hoshiyama
Graduate School of Biomedical Sciences, Hiroshima UniVersity, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
ReceiVed January 31, 2008
Phytochemical investigation of Trigonotis peduncularis resulted in the isolation of three aryldihydronaphthalene-type
lignan sucrose diesters named trigonotins A-C (1-3). These lignans showed a strong yellow-green fluorescence emission
under basic conditions. The structures of the new compounds were elucidated by means of spectroscopic methods, and
the nature of their fluorescence was examined.
Trigonotis peduncularis Benth. ex S. Moore & Baker (Boragi-
naceae) is a biennial herb of about 15 to 30 cm in height distributed
widely in the temperate zone of Asia. The Boraginaceae includes
many medicinal plants, such as Alkanna tinctoria, Lithospermum
erythrorhizon, and Macrotomia euchroma. However, no chemical
investigation of T. peduncularis has been conducted previously,
except for analyses of its essential oils1 and fatty acids.2 From the
whole parts of T. peducularis, three lignan sucrose diesters,
trigonotins A-C (1-3), were isolated along with rosmarinic acid3
and (6R,9R)-3-oxo-R-ionol-O-ꢀ-D-glucopyranoside.4,5 This paper
deals with the structural elucidation of the new compounds and
discusses the nature of the fluorescence emission of these trigonotins.
Results and Discussion
Trigonotin A (1), [R]D +491, was isolated as an amorphous,
yellow powder, and its elemental composition was determined to
be C35H40O19 by negative-ion HRFABMS. The IR spectrum showed
that compound 1 has a glycosidic unit (3403 and 1037 cm-1) and
contained absorption bands for esters (1717 cm-1) and aromatic
rings (1629, 1574, 1513, and 1502 cm-1). The UV spectrum also
indicated the presence of aromatic rings (253 and 355 nm). A total
of 35 carbon signals was observed in the 13C NMR spectrum and
were assigned for one tri- and one pentasubstituted benzene ring,
a trisubstituted double bond, two methines, and two carboxyl
functional groups, along with three methoxyl moieties and an acetyl
group (δC 172.8 and 20.4, and δH 1.64) (Tables 1 and 2). From
this evidence, the structure of the core portion of 1 was assigned
an aryldihydronaphthalene-type lignan with two carboxyl functional
groups. In the sugar signal region of the 13C NMR spectrum (δC
60-80), 11 carbon signals, three of which were primary alcohols,
were observed. Although this implied that two hexose moieties were
present in the molecule, only one anomeric proton (δH 5.41) and
carbon (δC 94.6), which showed a cross-peak in the HSQC
spectrum, were assigned. The coupling constant of the anomeric
proton was too small (J ) 3.7 Hz) to expect a D-sugar series having
a ꢀ-linkage. From these data, the sugar moiety was assigned as a
sucrose, with an R-glucopyranoside linked to fructopyranose. The
degree of unsaturation indicated one more cyclic system in the
pentasubstituted with three deshielded carbon atoms and an aryl
benzene ring ABX-type trisubstituted with two deshielded carbon
atoms. Therefore, the structure of trigonotin A (1) was proposed
as a sucrose diester of an aryldihydronaphthalene-type lignan. This
was confirmed by hydrolysis of trigonotin A (1) in 0.1 N CH3ONa
to give a hydrolysis product (1a) and sucrose (1b). NMR spectra
of the sucrose were identical with those of an authentic sample.
The small coupling value (J ) 1.3 Hz) between H-3 and H-4 was
consistent with the substituents on C-3 and C-4 having a cis
relationship. The first positive [∆ε +7.18 (360 nm)] and second
negative [∆ε -3.60 (312 nm)] Cotton effects in the CD spectrum
molecule. This was confirmed by the information obtained in the
HMBC experiment (Figure 1), and one of the carboxyl carbon
signals (δC 175.0) showed a cross-peak with a proton at δH 4.85
(H-3f), and the other (δC 168.9) with the protons at δH 4.91 and
4.07 (H2-6f). Since HMBC correlations were observed from δH 6.89
(H-8) to δC 142.4 (C-1) and δH 7.74 (H-1) to δC 168.9 (C-2a), and
from δH 6.66 (H-6′) to δC 40.0 (C-4) and δH 4.77 (H-4) to δC 175.0
(C-3a), the dihydronaphthalene benzene ring was assigned as
* To whom correspondence should be addressed. Tel and fax: +81-82-
257-5335. E-mail: hotsuka@hiroshima-u.ac.jp.
10.1021/np800071r CCC: $40.75
2008 American Chemical Society and American Society of Pharmacognosy
Published on Web 06/13/2008

Aryldihydronaphthalene-Type Lignans from T. peduncularis
Journal of Natural Products, 2008, Vol. 71, No. 7 1179
Table 1. 1H NMR Spectroscopic Data for Trigonotins A (1), B (2), and C (3)
position
1
2
3
1
3
4
5
7.74 (brd, 0.9)
4.09 (brd, 1.3)
4.77 (d, 1.3)
7.55 (d, 2.5)
7.70 (brd, 0.9)
3.95 (dd, 2.1, 0.9)
4.76 (d, 2.1)
4.20 (dd, 15.3, 2.5)
4.34 (dd, 15.3, 1.1)
6.14 (d, 1.1)
8
6.89 (brs)
6.94 (s)
6.87 (brs)
2′
6.61 (brs)
6.88 (d, 1.8)
6.65 (d, 2.0)
5′
6.60 (d, 7.7)
6.87 (d, 8.0)
6.69 (d, 8.1)
6′
6.66 (dd, 7.7, 0.9)
3.47 (s)
3.90 (s)
6.82 (d, 8.0, 1.8)
6.61 (dd, 8.1, 2.0)
3.49 (s)
3.90 (s)
OCH3-5
OCH3-7
OCH3-3′
1f
3.86 (s)
3.85 (s)
3.88 (d, 12.5)
3.72 (d, 12.5)
4.61 (s)
3.72 (s)
3.74 (s)
3.94 (d, 12.4)
3.73 (d, 12.4)
4.85 (s)
3.91 (d, 12.0)
3.78 (d, 12.0)
4.85 (s)
3f
4f
5f
6f
3.87 (s)
4.68 (s)
3.91 (s)
4.16 (brd, 2.9)
4.91 (dd, 13.0, 2.9)
4.07 (brd, 13.0)
5.41 (d, 3.6)
3.48 (dd, 9.5, 3.6)
3.76 (d, dd, 9.5, 9.5)
3.23 (dd, 9.5, 9.1)
4.30 (ddd, 9.1, 7.3, 1.7)
4.17 (dd, 11.8, 1.7)
4.01 (dd, 11.8, 7.3)
1.64 (s)
4.24 (brd, 2.4)
4.64 (dd, 12.0, 2.4)
4.06 (brd, 12.0)
5.31 (d, 3.7)
3.41 (dd, 9.4, 3.7)
3.63 (dd, 9.4, 9.2)
3.30 (m)
4.16 (brd, 2.8)
4.88 (dd, 12.8, 2.8)
4.08 (brd, 12.8)
5.40 (d, 3.7)
3.48 (dd, 9.2, 3.7)
3.74 (dd, 9.2, 9.2)
3.43 (dd, 10.1, 9.2)
4.03 (br dt, 10.1, 3.5)
3.58 (dd, 11.9, 4.0)
3.54 (dd, 11.9, 3.1)
1g
2g
3g
4g
5g
6g
4.27 (m)
4.22 (brd, 11.8)
4.09 (dd, 11.8, 5.6)
1.91 (s)
COCH3
Table 2. 13C NMR Spectroscopic Data for Trigonotins A (1), B
(2), and C (3)
of 1a indicated that the absolute configuration at C-4 is R and that
C-3 is also R. An acetyl group was placed on the hydroxyl group
of C-6g by the HMBC experiment (Figure 1) and the observed
low-field shifts of the C-6g and H2-6g signals in the NMR spectra,
when compared with the corresponding signals of 1 and sucrose.
Accordingly, the structure of trigonotin A was elucidated to be 1,
as shown.
position
1
2
3
1
2
2a
3
142.4
123.2
168.9
50.6
140.4
126.2
168.0
51.7
142.0
123.3
168.6
50.8
3a
4
175.0
40.0
176.2
48.2
174.9
40.2
Trigonotin B (2), [R]D +135, was isolated as an amorphous,
yellow powder, and its elemental composition was determined to
be C34H38O18 by negative-ion HRFABMS. The IR and UV spectra
5
6
7
8
9
10
1′
2′
3′
4′
5′
6′
147.0
144.5
149.2
110.2
123.2
125.6
137.5
112.7
148.9
146.6
116.6
121.5
60.7
116.4
148.0
150.4
113.9
135.0
124.3
133.6
114.6
149.2
147.0
117.0
123.6
147.1
144.5
149.2
110.1
123.1
125.7
133.7
112.7
148.9
146.4
116.6
121.5
60.7
1
showed similar absorption maxima to those of 1. The H and 13C
NMR spectra also indicated that in 2 one of the methoxyl groups
at C-5 (δC 60.7) in 1 was replaced by an aromatic proton, which
appeared at δH 6.14 and was coupled with H-4 (J ) 1.1 Hz). The
relative configuration of H-3 and H-4 was assigned as trans from
their large coupling constant (J ) 15.3 Hz), and the absolute
configuration of C-4 was deduced as R from the first positive [∆ε
+5.88 (345 nm)] and second negative [∆ε -2.15 (312 nm)] Cotton
effects in the CD spectrum of the hydrolysis product, 2a. Therefore,
the structure of trigonotin B was elucidated to be 2, as shown.
Trigonotin C (3), [R]D +394, was isolated as an amorphous,
yellow powder, and its elemental composition was determined to
be C33H38O18 by negative-ion HRFABMS. All physicochemical data
were similar to those of 1, except for the absence of the acetyl
group. The 13C NMR chemical shifts of C-4g, C-5g, and C-6g were
essentially the same as those of sucrose itself. Thus, 3 was
elucidated to be a deacetyl derivative of 1, as shown.
As far as we know, only two compounds have been isolated as
a sucrose diester, namely, 4,4′-dihydroxy-3,3′-dimethoxy-ꢀ-truxinic
acid fromAVena satiVa (oat)6 and 4,4′-dihydroxy-ꢀ-truxinic acid
from Bidens parViflora.7
During alkaline hydrolysis of trigonotin A (1), a strong deep
green-yellow luminescence emission was observed. Thus, fluores-
cence emission was analyzed in buffer solutions of various pH
values. In the 20 mM acetate buffer at pH 5.0, the excitation
maximum for trigonotin A (1) was 360 nm, but only slight emission
was observed at the wavelength of 526 nm with an arbitrary value
of 11.1 (Figure 2a). Under basic conditions at pH 8.0, the maximum
excitation wavelength shifted down to 435 nm and the magnitude
of the fluorescence was drastically enhanced at the wavelength of
526 nm with the arbitrary value of 685. At the same pH values,
OCH3-5
OCH3-7
OCH3-3′
1f
2f
3f
4f
5f
6f
1g
2g
3g
4g
5g
6g
COCH3
COCH3
57.0
56.8
63.6
109.8
80.4
75.3
88.2
66.4
94.6
73.6
75.3
72.1
72.2
66.0
172.8
20.4
56.9
56.8
63.4
110.3
82.3
73.5
87.6
66.6
94.6
73.6
75.2
71.2
71.2
65.4
173.0
20.7
57.0
56.7
63.5
110.2
80.5
75.6
88.1
66.6
95.0
73.7
75.2
71.2
74.2
62.2
the fluorescence strengths were the same and not influenced by the
different buffer solutions. Anionic forms of the phenolic hydroxyl
groups and proper torsion angles of the two aromatic systems in
the molecule might be important, since in the related compound
triogonotin B (2) the strength of the fluorescence was decreased
(Figure 2c). The methanolysis product (1a) of trigonotin A retained
its fluorescence propensity, but the strength was lower than that of

1180 Journal of Natural Products, 2008, Vol. 71, No. 7
Otsuka et al.
alkaline solution, the fluorescence emission decreased daily and
finally ceased completely. Thus, an ester of a carboxylic acid and
anionic forms of the phenolic hydroxyl groups were essential for
the emission of fluorescence, and interaction of the solvent
molecules with the lignan may affect the strength of the fluores-
cence. As far as we know, this is the first report of aryldihy-
dronaphthalene-typelignansthatshowstrongfluorescentluminescence.
Experimental Section
General Experimental Procedures. Optical rotations were measured
on a JASCO P-1030 digital polarimeter. FT-IR and UV spectra were
recorded on a Horiba FT-710 and a JASCO V-520 UV/vis spectro-
photometer, respectively. CD and fluorescence spectra were measured
with a JASCO J-720 polarimeter and a FP-6500 spectrophotometer,
1
respectively. H and 13C NMR spectra were taken on a JEOL R-400
spectrometer (400 and 100 MHz, respectively) with TMS as the internal
standard. HRFABMS were carried out on a JEOL SX-102 mass
spectrometer using PEG-400 as the calibration matrix. Silica gel column
chromatography (CC) and reversed-phase (ODS) gel open CC were
performed on silica gel 60 (Merck, 70-230 mesh) and Cosmosil 75C18-
OPN (Nacalai Tesque Co., Ltd., Kyoto, Japan) [L 50 mm,L ) 25 cm,
linear gradient: MeOH-H2O (1:9, 1 L) f (1:1, 1 L)], respectively,
with fractions of 10 g being collected. Droplet countercurrent chro-
matography (DCCC) was conducted on a Tokyo Rikakikai (Tokyo,
Japan) instrument, equipped with 500 glass columns (L ) 2 mm, L )
40 cm), and the lower and upper layers of a solvent mixture of
CHCl3-MeOH-H2O-n-PrOH (9:12:8:2) were used as the stationary
and mobile phase, respectively. Five-gram fractions were collected and
numbered according to the order of elution of the mobile phase.
Preparative HPLC was performed using ODS (YMC-Pack, L ) 20
mm, L ) 15 cm, YMC, Kyoto, Japan) or ODS (Inertsil, L ) 6 mm, L
) 25 cm, GL Science, Tokyo, Japan) columns.
Figure 1. Selected HMBC correlations of trigonotin A (1).
Plant Material. Trigonotis peduncularis was collected in Hiroshima
City, Japan, in May 2000. The plant was identified by Prof. Takakazu
Shinzato of University of the Ryukyus, and a voucher specimen was
deposited in the Herbarium of Pharmaceutical Sciences, Graduate
School of Biomedical Sciences, Hiroshima University (00-TP-Hi-
roshima-0507).
Extraction and Isolation. Air-dried leaves of T. peduncularis (3.04
kg) were extracted with MeOH (15 L) three times. The MeOH extract
was concentrated to 1.5 L, and then 75 mL of H2O was added to make
a 95% aqueous solution. This solution was washed with 1.5 L of
n-hexane, and the methanolic layer was concentrated to a viscous gum.
The gummy residue was suspended in 1.5 L of H2O and then extracted
with 1.5 L each of EtOAc and 1-BuOH, successively, to give 26.2 g
of an EtOAc-soluble extract and 35.6 g of a 1-BuOH-soluble extract.
The 1-BuOH extract fraction was subjected to highly porous synthetic
resin CC (Diaion HP-20, Mitsubishi Chemical Co., Ltd., L ) 55 mm,
L ) 36 cm) using H2O-MeOH (4:1, 3 L; 2:3, 2 L; 3:2, 2 L; and 1:4,
2 L) and MeOH (2 L), with 500 mL fractions being collected. The
residue (11.3 g in fractions 12-15) of the 40% MeOH eluent was
subjected to silica gel (250 g) CC, with elution by CHCl3 (2 L) and
CHCl3-MeOH [(99:1, 2 L), (49:1, 2 L), (24:1, 2 L), (47:3, 2 L), (23:
2, 2 L), (9:1, 2 L), (7:1, 2 L), (17:3, 2 L), (33:7, 2 L), (4:1, 2 L), (3:1,
2 L), and (7:3, 2 L)], with again 500 mL fractions being collected.
Combined fractions 21-30 (2.76 g) were separated by reversed-phase
(ODS) gel open CC. The residue (884 mg) of fractions 114-126 was
subjected to DCCC to give 388 mg of 1 in fractions 88-97 and 33 mg
of (6R,9R)-3-oxo-R-ionol-O-ꢀ-D-glucopyranoside in fractions 121-140.
The residue (164 mg) of fractions 140-147 was subjected to DCCC
to give 62.3 mg of 2 in fractions 88-97 and 33.0 mg of (6R,9R)-3-
oxo-R-ionol-O-ꢀ-D-glucopyranoside in fractions 120-139. The residue
(3.11 g in fractions 31-40) obtained on silica gel CC (12.5-17.5%
MeOH eluent) was subjected to open reversed-phase (ODS) gel CC,
and the residue (81 mg in fractions 98-105) was then separated by
DCCC to give 32.4 mg of 3 in fractions 41-51.The residue (1.12 g in
fractions 48-54) obtained on silica gel CC was subjected to reversed-
phase (ODS) gel open CC to give 197 mg of rosemarinic acid in
fractions 51-76.
Figure 2. Emission spectra of (a) trigonotin A (1), (b) the trigonotin
A hydrolysis product (1a), (c) trigonotin B (2), and (d) trigonotin
C (3).
Trigonotin A (1): amorphous, yellow powder; [R]D25 +491 (c 1.03,
MeOH); IR νmax (film) 3403, 2942, 1717, 1629, 1574, 1513, 1502, 1457,
1349, 1272, 1204, 1107, 1037 cm-1; UV (log ε) λmax (MeOH) 253
(4.25), 355 (4.09) nm; CD (c 5.36 × 10-5 M, MeOH) -8.87 (227),
1 (Figure 2b). A simple 1:1 mixture of 1a and sucrose (1b) did not
restore the fluorescence ability (data not shown). In an aqueous
1
-21.7 (256), +4.76 (293), +19.0 (360) ∆ε (nm); H and 13C NMR

Aryldihydronaphthalene-Type Lignans from T. peduncularis
Journal of Natural Products, 2008, Vol. 71, No. 7 1181
(CD3OD), Tables 1 and 2, respectively; HRFABMS (negative-ion
mode) m/z 763.2065 [M - H]- (calcd for C35H39O19, 763.2086).
Trigonotin B (2): amorphous, yellow powder; [R]D25 +135 (c 1.19,
MeOH); IR νmax (film) 3396, 2942, 1725, 1626, 1569, 1515, 1451, 1370,
1249, 1025 cm-1; UV (log ε) λmax (MeOH) 249 (4.23), 340 (4.03) nm;
CD (c 6.53 × 10-5 M, MeOH) +3.66 (230), +4.81 (257), +6.04 (293),
Mild Alkaline Hydrolysis of Trigonotin B (2). Similar treatment
of trigonotin B (2) (24.3 mg) to 1 gave 9.9 mg of 2a. Trigonotin B
hydrolysis product (2a): amorphous, pale yellow powder; [R]D25 +147
(c 0.66, MeOH); IR νmax (film) 3406, 2951, 1701, 1601, 1576, 1513,
1270, 1240, 1210 cm-1; UV (log ε) λmax (MeOH) 249 (4.22), 289 sh
(3.81), 313 sh (3.94), 340 (4.06) nm; CD (c 3.99 × 10-5 M, MeOH)
+1.36 (233), -8.41 (252), +2.38 (290), -2.15 (312), +5.88 (345) ∆ε
1
+0.85 (368) ∆ε (nm); H and 13C NMR (CD3OD), Tables 1 and 2,
1
respectively; HRFABMS (negative-ion mode) m/z 733.2005 [M - H]-
(calcd for C34H37O18, 733.1980).
(nm); H NMR (CD3OD) δ 3.59 (3H, s, C-3a-OCH3), 3.731 (3H, s,
C-2a-OCH3 or C-3′-OCH3), 3.733 (3H, s, C-3′-OCH3 or C-2a-OCH3),
3.89 (3H, s, C-7-OCH3), 3.92 (1H, d, J ) 3.8 Hz, H-3), 4.46 (1H, brd,
J ) 3.8 Hz, H-4), 6.41 (1H, ddd, J ) 0.5, 2.2, 8.2 Hz, H-6′), 6.55 (1H,
s, H-5), 6.63 (1H, d, J ) 2.2 Hz, H-2′), 6.64 (1H, d, J ) 8.2 Hz, H-5′),
7.00 (1H, s, H-1), 7.68 (1H, s, H-1); 13C NMR (CD3OD) δ 47.2 (C-4),
49.1 (C-3), 52.4 (C-2a-OCH3), 52.8 (C-3a-OCH3), 56.5 (C-7-OCH3),
56.7 (C-3′-OCH3), 112.5 (C-8), 113.8 (C-4), 116.2 (C-5), 117.2 (C-
5′), 121.4 (C-6′), 123.1 (C-6′), 124.9(C-10), 132.7 (C-1′), 135.4 (C-9),
139.7 (C-1), 146.6 (C-4′), 148.5, 149.0 (C-3′), 150.4 (C-8), 169.0 (C-
2a), 175.0 (C-3a); HRFABMS (negative-ion mode) m/z 413.1253 [M
- H]- (calcd for C22H21O8, 413.1236).
Measurement of Fluorescence. The buffer solutions used were as
follows: 20 mM acetate buffer for pH 5.0, 20 mM phosphate buffer
for pH 6.0, 7.0, and 8.0, 20 mM borate buffer for pH 8.0 and 9.0, and
carbonate buffer for pH 9.0 and 10.0. The concentrations were adjusted
to be 1 µM, and fluorescence was measured at 25 °C. Maximum
excitation wavelengths were determined by measurement of emission
spectra.
Trigonotin C (3): amorphous, yellow powder; [R]D25 +394 (c 1.65,
MeOH); IR νmax (film) 3396, 2940, 17157, 1629, 1574, 1513, 1459,
1270, 1204 cm-1; UV (log ε) λmax (MeOH) 252 (4.17), 350 (4.02) nm;
CD (c 9.22 × 10-5 M, MeOH) -8.54 (228), -19.1 (256), +5.21 (291),
1
+17.2 (359) ∆ε (nm); H and 13C NMR (CD3OD), Tables 1 and 2;
respectively; HRFABMS (negative-ion mode) m/z 721.1952 [M - H]-
(calcd for C33H37O18, 721.1980).
Mild Alkaline Hydrolysis of Trigonotin A (1). Trigonotin A (1)
(52.6 mg) was treated with 4 mL of 0.1 N CH3ONa (4.5 mL) for 24 h
at 50 °C under a N2 stream. The reaction mixture was neutralized with
Amerlite IR-120B (H+) (Organo) and then filtered and evaporated to
dryness. The residue was purified by silica gel column chromatography
(L ) 15 mm, L ) 20 cm) with CHCl3 (150 mL), CHCl3-MeOH (9:1)
(200 mL), and CHCl3-MeOH-H2O (35:15:2) (300 mL), with 10 g
fractions being collected. The hydrolysis product (1a) (10.3 mg) was
obtained in fractions 20-22. The CHCl3-MeOH-H2O eluate was
evaporated to afford 2.6 mg of sucrose (1b).
Trigonotin A Hydrolysis Product (1a): amorphous, pale yellow
powder; [R]D25 +138 (c 0.69, MeOH); IR νmax (film) 3417, 2950, 1700,
1632, 1605, 1575, 1513, 1461, 1269, 1208 cm-1; UV (log ε) λmax
(MeOH) 249 (4.24), 291sh (3.82), 332 (4.10) nm; CD (c 6.19 × 10-5
M, MeOH) -10.5 (230), -4.87 (253), +1.71 (293), -3.60 (312), +7.18
Acknowledgment. Prof. Takakazu Shinzato, University of the
Ryukyus, is acknowledged for identification of the plant material. The
authors are grateful for access to the superconducting NMR instrument
at the Analytical Center of Molecular Medicine of the Graduate School
of Biomedical Sciences, Hiroshima University.
1
(360) ∆ε (nm); H (CD3OD) δ 3.54 (3H, s, C-5-OCH3), 3.61 (3H, s,
C-3a-OCH3), 3.71 (3H, s, C-3′-OCH3), 3.72 (3H, s, C-2a-OCH3), 3.89
(3H, s, C-7-OCH3), 3.93 (1H, d,J ) 1.2 Hz, H-3), 4.95 (1H, brs, H-4),
6.14 (1H, d,J ) 1.1 Hz, H-5), 6.53 (1H, dd,J ) 2.0, 8.3 Hz, H-6′),
6.59 (1H, d,J ) 8.3 Hz, H-5′), 6.63 (1H, d,J ) 2.0 Hz, H-2′), 6.87
(1H, s, H-8), 7.68 (1H, s, H-1); 13C NMR (CD3OD) δ 40.7 (C4), 48.2
(C-3), 52.4 (C-2a-OCH3), 52.9 (C-3a-OCH3), 56.3 (C-3′-OCH3), 56.8
(C-7OCH3), 60.7 (C-5-OCH3), 112.2 (C-2′), 116.0 (C-5′), 119.5 (C-
8), 120.9 (C-6′), 123.0 (C-9), 125.1 (C-10), 124.3 (C-2), 135.4 (C-1′),
139.8 (C-1), 143.6 (C-6), 148.8 (C-3′), 146.3 (C-4′), 146.8 (C-5), 149.4
(C-7), 169.0 (C-2a), 174.3 (C-3a); HRFABMS (negative-ion mode)
m/z 443.1377 [M - H]- (calcd for C23H23O9: 443.1342).
References and Notes
(1) Fujita, S.; Nogami, K. Nippon Nogei Kagaku Kaishi 1993, 67, 1185–
1188.
(2) Fujita, S.; Nogami, K. Mukogawa Joshi Daigaku Kiyo, Shizen Kagaku-
hen 1995, 43, 1-3.
(3) Kelly, C. J.; Mahajan, J. R.; Brooks, L. C.; Neubert, L. A.; Breneman,
W. R. J. Org. Chem. 1975, 40, 1804–1815.
(4) Pabst, A.; Barron, D.; Se´mon, E.; Schreier, P. Phytochemistry 1992,
31, 1649–1652.
(5) Otsuka, H.; Hirata, E.; Shinzato, T.; Takeda, Y. Chem. Pharm. Bull.
2000, 48, 1084–1086.
(6) Dimberg, L. H.; Anderson, R. E.; Gohil, S.; Bryngelsson, S.; Lundgren,
L. N. Phytochemistry 2001, 56, 843–847.
(7) Wang, N.; Yao, X.; Ishii, R.; Kitanaka, S. Phytochemistry 2003, 62,
741–746.
Sucrose (1b): amorphous, white powder; [R]D25 +60 (c 0.17, H2O);
1H NMR (CD3OD) δ 5.39 (1H, d, J ) 3.7 Hz, H-1g); 13C NMR
(CD3OD) δ 62.4 (C-6g), 63.4 (C-1f), 64.2 (C-6f), 71.5 (C-4g), 73.3
(C-2g), 74.5 (C-5g), 74.9 (C-3g), 75.9 (C-4f), 79.6 (C-3f), 83.9 (C-
5f), 93.7 (C-1g), 105.4 (C-2f).
NP800071R