New cardenolide and acylated lignan glycosides from the aerial parts of Asclepias curassavica

Article abstract of DOI:10.1248/cpb.56.1159

Three new cardenolide glycosides and six new acylated lignan glycosides were obtained along with nineteen known compounds from the aerial parts of Asclepias curassavica L. (Asclepiadaceae). The structure of each compound was determined based on interpreta

Full text of DOI:10.1248/cpb.56.1159

August 2008
Chem. Pharm. Bull. 56(8) 1159—1163 (2008)
1159
New Cardenolide and Acylated Lignan Glycosides from the Aerial Parts
of Asclepias curassavica
a
Tsutomu WARASHINA,*,a Kimiko SHIKATA,b Toshio MIYASE,b Satoshi FUJII,b and Tadataka NORO
a Institute for Environmental Sciences, University of Shizuoka; and b School of Pharmaceutical Sciences, University of
Shizuoka; 52–1 Yada, Suruga-ku, Shizuoka 422–8526, Japan.
Received May 7, 2008; accepted June 10, 2008: published online June 11, 2008
Three new cardenolide glycosides and six new acylated lignan glycosides were obtained along with nineteen
known compounds from the aerial parts of Asclepias curassavica L. (Asclepiadaceae). The structure of each com-
pound was determined based on interpretations of NMR and MS measurements and chemical evidence.
Key words Asclepias curassavica L.; Asclepiadaceae; cardenolide glycoside; lignan glycoside
Asclepias curassavica L. (Asclepiadaceae), a common gar- spectroscopic data of 19 were similar to those of 11 and 12
den plant in Japan, contains many kinds of cardenolides and except for the exchange of a quaternary oxygenated carbon
cardenolide glycosides.1—3) The monarch butterfly (Danaus signal (d 72.7) for a quaternary carbon and disappearance of
plexippus L.) feeds on the Asclepias genus, including A. the C-19 signal. In addition, the 1H-NMR spectrum of 19 re-
curassavica, for protection from vertebrate predators.4—6) In vealed a hydroxyl proton signal at d 5.18. In the HMBC
the course of our research on the phytochemicals in Asclepi- spectrum, long-range correlations were observed from this
adaceaus plants, we have also investigated the constituents of hydroxyl proton signal to the C-1 (d 41.1), C-5 (d 44.4), C-9
the aerial parts of A. curassavica.
(d 48.7) and above quaternary oxygenated carbon signals.
A MeOH extract from the dried aerial parts of A. curas- Thus, this quaternary oxygenated carbon signal was assigned
savica was suspended in water. The suspension was extracted at the C-10 position and the hydroxy group was placed at C-
with diethyl ether and partitioned into an ether-soluble frac- 10. The rotating frame nuclear Overhauser effect (ROE) dif-
tion and a water-soluble fraction. The residue of the water- ference experiment suggested that this hydroxy group re-
soluble fraction, after passing through a porous polymer gel, tained a b orientation, owing to the observation of ROEs be-
was chromatographed on a silica gel column to give fractions tween this hydroxyl proton and H-1b (d 2.47), H-2 (d 5.06),
of cardenolides, cardenolide glycosides, lignan and acylated H-4b (d 1.99), and H-8 (d 2.17). Thus, 19 was identified as
1
lignan glycosides, from which nine new compounds were ob- be 19-nor-10b-hydroxyasclepin. The similarity of the H-
tained.
and 13C-NMR spectroscopic data of 19 to those of 18 sup-
Compounds 1—11, 13—17 and 18 were known cardeno- ported this finding (see Table 1 and Experimental).
lides and cardenolide glycosides, and identified as uzarigenin
HR-FAB-MS of compound 20 afforded a [MꢁNa]ꢁ peak
(1),1,7—9) 5,6-dehydrouzarigenin (xysmalogenin) (2),8—11) at m/z 531.2569, suggesting the molecular formula,
coroglaucigenin (3),1,12) gofruside (4),12,13) 6ꢀ-O-(E-4-hydroxy- C29H38O9. Compound 20 was also considered to be a carde-
cinnamoyl)-desglucouzarin (5),14,15) 6ꢀ-O-sinapinoyl-desglu- nolide glycoside, according to the appearance of typical sig-
couzarin (6),16) calactin (7),17—19) 16a-acetoxycalactin (8),16) nals due to an a,b-unsaturated-g-lactone, one aldehyde, two
calotropin (9),17—20) 16a-acetoxycalotropin (10),21) asclepin secondary oxymethines, and one quaternary oxygenated car-
(11),19) 16a-hydroxyasclepin (13),21) 16a-acetoxyasclepin bon in the 1H- and 13C-NMR spectra of the aglycone moiety,
(14),21) uscharin (15),17—19) 16a-hydroxyuscharin (16),22) together with the anomeric proton and carbon signals at d
uscharidin (17)17—19) and 19-nor-16a-acetoxy-10b-hydroxyas- 5.63 (1H, s) and d 104.6 in the sugar moiety. Based on a
1
clepin (18).3) Compounds 21 and 22 were also identical to comparison of the H- and 13C-NMR spectroscopic data of
known lignans, (ꢁ)-medioresinal and (ꢁ)-syringaresinol, re- 20 with those of calactinic acid methyl ester,3) the sugar moi-
spectively.23)
ety of 20 was presumed to consist of a furanose form. This
Compound 12 was suggested to have the molecular for- presumption was supported by the long-range correlations
mula C31H44O10 based on high resolution (HR)-FAB-MS from H-1ꢀ (d 5.63) to C-2ꢀ (d 88.3), C-4ꢀ (d 45.3) and C-5ꢀ
1
[m/z: 599.2806 [MꢁNa]ꢁ]. On comparison of the H- and (d 74.1) and from H-4ꢀ (d 2.64 and/or 2.61) to C-1ꢀ, C-2ꢀ
13C-NMR spectra of 12 with those of 11, hydroxy methyl and C-5ꢀ in the HMBC experiment of 20. Moreover, the ob-
proton and carbon signals were observed at d 4.01 (1H, dd, served HMBC correlations between H-4ꢀ and C-3ꢀ (d 172.5),
Jꢂ11.5, 3.0 Hz), 3.74 (1H, dd, Jꢂ11.5, 3.0 Hz) and d 59.3 C-3ꢀ and H-2 (d 5.56), H-1ꢀ and C-3 (d 78.3), and H-3 (d
instead of the aldehyde proton and carbon signals. In the het- 3.93) and C-1ꢀ (d 104.6) suggested that the sugar unit was at-
eronuclear multiple-bond connectivity (HMBC) experiment, tached to the C-3 position by a glycosidic linkage and the C-
these proton signals exhibited long-range correlations to the 2 position by an esterified linkage. Because, in the ROE dif-
C-1 (d 37.8), C-5 (d 45.4), C-9 (d 51.5) and C-10 (d 41.9) ference experiment, ROEs were exhibited between H-2 and
signals. Thus, this hydroxy methyl group was located at the H-19 (d 10.19), H-3 and H-1a (d 1.23), H-5 (d 1.40), the
C-19 position, and compound 12 was determined as 19-dihy- orientation of H-2 and H-3 was determined as b and a, re-
droasclepin.
spectively. In addition, observations of ROEs from H-1ꢀ to
The molecular formula of compound 19 was proposed to H-2 and H-5ꢀ suggested that H-1ꢀ and H-5ꢀ retained the b-
1
be C30H42O10 based on HR-FAB-MS. The H- and 13C-NMR orientation. The orientation of the hydroxyl group at C-2ꢀ
∗ To whom correspondence should be addressed. e-mail: warashin@sea.u-shizuoka-ken.ac.jp
© 2008 Pharmaceutical Society of Japan

1160
Vol. 56, No. 8
Table 1. 13C-NMR Data of Compounds 11, 12, 18, 19 and 20
11
12
18
19
20
Carbon No.
1
2
3
4
5
6
7
8
9
36.6
69.4
72.3
32.5
43.5
28.0
28.0
42.6
48.8
53.0
22.2
39.3
49.8
84.1
33.9
27.2
51.2
15.9
207.8
175.5
73.7
117.9
174.4
97.0
91.8
75.3
36.3
68.1
21.3
170.7
21.0
—
37.8
69.5
73.1
33.5
45.4
28.0a)
27.8a)
41.8b)
51.5
41.9b)
23.5
40.4
50.2
84.7
33.2
27.4
50.6
16.3
59.3
175.9
73.7
117.7
174.5
97.3
91.7
75.6
36.4
68.0
21.3
170.7
20.9
—
40.9
69.5
72.6a)
32.7
44.4
28.1
27.6
40.9
48.7
72.7a)
21.4
40.1
49.6
84.2
39.8
79.3
58.4
16.1
—
173.0
74.1
118.3
174.3
97.3
91.8
75.5
36.3
68.1
21.3
170.7b)
21.0
170.9b)
21.0
41.1a)
69.6
72.6b)
32.8
44.4
28.2
27.5c)
40.8a)
48.7
72.7b)
21.3
39.6
50.0
84.3
33.2
27.4c)
51.4
16.1
—
175.9
73.7
117.7
174.5
97.3
91.8
75.5
36.4
68.1
21.3
170.7
21.0
—
36.6
74.4
78.3
32.0
48.2
27.9a)
27.8a)
43.5
42.5
52.8
22.5
39.1
49.8
84.1
32.4
27.2
51.2
15.8
207.9
175.5
73.7
117.9
174.4
104.6
88.3
172.5
45.3
74.1
20.9
—
Fig. 1. ORTEP Drawing of Compound 20
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
1ꢄ
2ꢄ
1ꢅ
2ꢅ
—
—
—
—
—
—
Measured in pyridine-d5 at 35 °C. a, b, c) Signal assignments may be interchanged in
each column.
was assigned as b based on the result of a X-ray analysis
(Fig. 1). Thus, the structure of 20 was identified as shown in
Chart 1, and the compound was named calactinolactone. It
was suggested that compound 20 might be an artifact of the
autoxidation of uscharidin (17).3)
Chart 1. Structures of Compounds 11, 12, 17—20, 23—27 and 28
HR-FAB-MS of compound 23 exhibited an [M]ꢁ ion at
m/z 758.2776, revealing the molecular formula of 23 to be
C38H46O16. The 13C-NMR spectrum of 23 showed the signals
of two tetra-substituted symmetrical aromatic rings (d 149.2ꢃ
2, 137.0, 134.3, 104.7ꢃ2 and d 149.2ꢃ2, 136.1, 131.7,
107.3ꢃ2), three methylenes (d 68.3, 73.1, 34.3), three me-
thines (d 83.5, 51.3, 43.6), and four methoxy groups (d
56.5ꢃ4) in the aglycone moiety, along with the presence of
b-D-glucopyranosyl and trans-feruloyl groups. From the 13C-
NMR spectroscopic data, the aglycone of 23 was expected to
be a tetrahydrofuran-type lignan. The deacylated compound
23a afforded by alkaline hydrolysis of 23 was identified as
(8R,7ꢀS,8ꢀR)-5,5ꢀ-dimethoxylariciresinol 9ꢀ-O-b-D-glucopy-
1
ranoside, the H-, 13C-NMR spectroscopic data and circular
dichroism (CD) spectrum being consistent with those of
1
alangilignoside C.24,25) Moreover, the H-NMR spectrum of
23 revealed downfield shifts of the H-6 signals of the b-D-
glucopyranosyl group (d 5.14, 5.01), and the HMBC meas-
urement showed long-range correlations from the carbonyl
carbon signal of the trans-feruloyl group (d 167.6) to these
H-6 signals of the b-D-glucopyranosyl group. The above re- Chart 2. ROE and HMBC Correlations in Compounds 19 and 20

August 2008
1161
Table 2. 13C- and 1H-NMR Data of Compounds 23 and 27
23ꢁ
23ꢁꢁ
27ꢁꢁ
Carbon and Proton No.
Aglycone moiety
1
2
3
4
5
6
7
131.7
107.3
149.2
136.1
149.2
107.3
34.3
—
6.73 (s)
—
—
—
6.73 (s)
3.29 (dd, 13.5, 4.5)
2.74 (dd, 13.5, 11.5)
3.03 (m)
4.27 (dd, 8.5, 6.5)
4.02 (dd, 8.5, 6.5)
3.78 (s)ꢃ2
—
7.12 (s)
—
—
—
132.9
107.2
149.3a)
134.9b)
149.3a)
107.2
34.5
—
6.43 (s)
—
—
—
6.43 (s)
2.90 (dd, 13.5, 5.0)
2.47 (dd, 13.5, 11.0)
2.73 (m)
3.96 (dd, 8.5, 6.5)
3.70 (dd, 8.5, 6.5)
133.6
113.5
149.0
145.8
116.2
122.2
33.9
—
6.72 (d, 2.0)
—
—
6.67 (d, 8.0)
6.56 (dd, 8.0, 2.0)
2.88 (dd, 13.5, 5.0)
2.46 (dd, 13.5, 11.0)
2.72 (m)
3.95 (dd, 8.5, 6.5)
3.67 (dd, 8.5, 7.0)
3.78 (s)
—
6.64 (s)
—
—
8
9
43.6
73.1
44.1
73.7
44.1
73.8
OMe
1ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
7ꢀ
8ꢀ
56.5ꢃ2
134.3
104.7
149.2
137.0
149.2
104.7
83.5
56.9c)ꢃ2 3.77 (s)ꢃ2
56.9
135.1
104.5
149.2
135.9
149.2
104.5
84.8
135.0b)
104.6
149.2a)
136.0
149.2a)
104.6
84.6
—
6.64 (s)
—
—
—
6.64 (s)
4.85 (d, 6.5)
2.49 (m)
—
6.64 (s)
4.86 (d, 6.5)
2.48 (m)
7.12 (s)
5.33 (d, 6.5)
2.86 (m)
51.3
51.6
51.4
9ꢀ
68.3
4.52 (dd, 10.0, 6.5)
4.15**
3.81 (s)ꢃ2
68.9
4.00 (dd, 10.0, 6.0)
3.85 (dd, 10.0, 6.0)
68.9
3.99 (dd, 10.0, 6.5)
3.85 (dd, 10.0, 6.5)
OMeꢀ
56.5ꢃ2
56.8c)ꢃ2 3.81 (s)ꢃ2
56.9ꢃ2 3.80 (s)ꢃ2
Sugar moiety
Glc-1
-2
105.1
75.2
78.5
71.5
75.6
64.6
4.99 (d, 8.0)
4.13 (t, 8.0)
4.26 (t, 8.0)
4.19**
4.16**
5.14 (dd, 12.0, 2.0)
5.01 (dd, 12.0, 5.5)
104.6
75.2
78.0
71.9
75.5
64.4
4.33 (d, 8.0)
3.26 (t, 8.0)
3.39**
3.39**
3.54 (m)
104.5
75.2
78.1
71.9
75.5
64.5
4.32 (d, 8.0)
3.25 (t, 8.0)
3.39**
3.39**
3.55 (m)
-3
-4
-5
-6
4.54 (dd, 12.0, 2.0)
4.40 (dd, 12.0, 6.0)
4.53 (dd, 12.0, 2.0)
4.40 (dd, 12.0, 6.0)
Ester moiety
1ꢄ
2ꢄ
3ꢄ
4ꢄ
5ꢄ
6ꢄ
7ꢄ
8ꢄ
126.5
111.5
149.0
151.2
116.8
*
145.8
115.1
167.6
56.0
—
7.21*
—
—
7.15 (br s)
7.15 (br s)
7.93 (d, 16.0)
6.62 (d, 16.0)
—
127.6
111.8
149.4
150.7
116.5
124.1
147.0
115.2
169.0
56.5
—
127.6
111.8
149.4
150.7
116.5
124.2
147.1
115.3
169.0
56.5
—
7.08 (d, 2.0)
—
—
6.77 (d, 8.0)
6.97 (dd, 8.0, 2.0)
7.57 (d, 16.0)
6.32 (d, 16.0)
—
7.09 (d, 2.0)
—
—
6.78 (d, 8.0)
6.99 (dd, 8.0, 2.0)
7.59 (d, 16.0)
6.34 (d, 16.0)
—
9ꢄ
OMeꢄ
3.77 (s)
3.82 (s)
3.82 (s)
ꢁ: Measured in pyridine-d5 at 35 °C. ꢁꢁ: Measured in MeOH-d4 at 35 °C. a, b, c) Signal assignments may be interchanged in each column. ∗ Overlapping with pyridine-d5
signals. ∗∗ Overlapping with other signals.
sults suggested that the C-6 position of the b-D-glucopyra- dd, Jꢂ8.0, 2.0 Hz); 28: d 6.74 (1H, d, Jꢂ2.0 Hz), 6.69 (1H,
nosyl group was acylated by trans-ferulic acid. Hence, the d, Jꢂ8.0 Hz), 6.61 (1H, dd, Jꢂ8.0, 2.0 Hz)] with one set of
structure of 23 was elucidated as shown in Chart 1.
tetra-substituted symmetrical aromatic proton signals. Com-
From the results of HR-FAB-MS, compounds 24—26 had pound 27a produced by alkaline hydrolysis of 27 was identi-
the molecular formulae, C38H46O16, C37H44O15 and C39H48O17, fied as (8R,7ꢀS,8ꢀR)-5ꢀ-methoxylariciresinol 9ꢀ-O-b-D-glu-
1
respectively. On the basis of the H- and 13C-NMR spectro- copyranoside based on a comparison with the 1H-, 13C-NMR
scopic data, the aglycone and sugar moieties of 24—26 were spectroscopic data and CD spectrum of alangilignoside D.24)
identified as 23a, their NMR spectroscopic data being con- In consideration of the production of trans-ferulic acid from
sistent with those of 23 except for their ester moieties. Be- 27 by alkaline hydrolysis, the structure of 27 was determined
cause alkaline hydrolysis afforded cis-ferulic acid, trans-p- as shown in Chart 1. The structure of compound 28 was also
coumaric acid and trans-sinapinic acid from 24, 25 and 26, established, based on a comparison of the NMR spectro-
respectively, together with 23a, their structures were estab- scopic data with those of 24 and 27 and the result of alkaline
lished as shown in Chart 1.
hydrolysis of 28.
The molecular formula of both compounds 27 and 28 was
A previous paper reported that mainly pregnane glycosides
proposed to be C37H44O15. The 1H-NMR spectra of 27 and 28 were contained in the roots of A. curassavica along with a
showed one set of ABX-type aromatic proton signals [27: d few kinds of cardenolide glycosides.26) In this investigation,
6.72 (1H, d, Jꢂ2.0 Hz), 6.67 (1H, d, Jꢂ8.0 Hz), 6.56 (1H, the aerial parts of this plant afforded many kinds of cardeno-

1162
Vol. 56, No. 8
OCOCH3*), 2.10 (1H, dd, 12.0, 4.5, H-1), 2.07 (1H, dd, 13.5, 8.0, H-15),
2.04 (3H, s, C-16-OCOCH3*), 1.86 (1H, ddd, 12.0, 5.0, 2.0, H-4ꢀ), 1.73 (1H,
q, 12.0, H-4ꢀ), 1.31 (3H, d, 6.5, H-6ꢀ), 1.29 (1H, t, 12.0, H-1), 1.20 (1H, td,
12.0, 3.0, H-9), 0.87 (3H, s, H-18).
lides and cardenolide glycosides without pregnane glyco-
sides. A marked difference in the constituents of this plant
was found between the aerial parts and roots. A. curassavica
is toxic, probably due to the cardenolides and their glyco-
19-Nor-10b-hydroxyasclepin (19): Amorphous powder. [a]D22 ꢁ22° (cꢂ
sides. We were interested in the cardiotoxicity and inhibitory 0.60, MeOH). FAB-MS m/z: 563 [MꢁH]ꢁ, 585 [MꢁNa]ꢁ. HR-FAB-MS
effect on Naꢁ–Kꢁ ATPase of these compounds.
m/z: 563.2854, 585.2676 (Calcd for C30H43O10: 563.2856 and C30H42O10Na:
585.2676). 13C-NMR (pyridine-d5 at 35 °C): shown in Table 1. 1H-NMR
(pyridine-d5 at 35 °C) d: 6.10 (1H, br t, 1.5, H-22), 5.42 (1H, dd, 12.0, 5.0,
H-3ꢀ), 5.27 (1H, dd, 18.5, 1.5, H-21), 5.25 (1H, s, C-14-OH), 5.18 (1H, s, C-
10-OH), 5.06 (1H, s, H-1ꢀ), 5.06 (overlapping, H-2), 5.01 (1H, dd, 18.5, 1.5,
H-21), 4.46 (1H, ddd, 12.0, 10.0, 4.5, H-3), 3.79 (1H, m, H-5ꢀ), 2.74 (1H,
dd, 9.0, 5.0, H-17), 2.47 (1H, dd, 12.0, 4.5, H-1), 2.17 (1H, td, 12.0, 3.0, H-
8), 2.10 (overlapping, H-4ꢀ), 1.99 (1H, q, 12.0, H-4), 1.97 (overlapping, H-
4ꢀ), 1.87 (3H, s, C-3ꢀ-OCOCH3*), 1.47 (1H, t, 12.0, H-1), 0.98 (3H, s, H-
18). 13C-NMR (CDCl3 at 35 °C) d: 174.3, 174.2 (C-20, -23), 172.3 (C-3ꢀ-
OC*OCH3), 117.8 (C-22), 96.1 (C-1ꢀ), 90.9 (C-2ꢀ), 85.0 (C-14), 75.7 (C-3ꢀ),
73.4 (C-21), 73.0 (C-10), 71.5 (C-3), 68.9 (C-2), 67.8 (C-5ꢀ), 50.7 (C-17),
49.4 (C-13), 48.0 (C-9), 43.4 (C-5), 41.1 (C-8), 39.6, 39.4 (C-1, -12), 35.5
(C-4ꢀ), 32.9 (C-15), 31.6 (C-4), 27.4 (C-6), 26.9, 26.5 (C-7, -16), 21.1 (C-3ꢀ-
OCOC*H3), 20.9 (C-6ꢀ), 20.7 (C-11), 15.7 (C-18). 1H-NMR (CDCl3 at
35 °C) d: 5.87 (1H, br t, 1.5, H-22), 4.97 (1H, dd, 18.0, 1.5, H-21), 4.79 (1H,
dd, 18.0, 1.5, H-21), 4.78 (1H, dd, 12.0, 5.0, H-3ꢀ), 4.59 (1H, s, H-1ꢀ), 4.22
(1H, ddd, 12.0, 10.5, 4.5, H-2), 3.97 (1H, td, 10.5, 6.0, H-3), 3.70 (1H, m, H-
5ꢀ), 2.76 (1H, dd, 9.5, 5.5, H-17), 2.14 (3H, s, C-3ꢀ-OCOCH3*), 2.10 (1H,
dd, 12.0, 4.5, H-1), 1.86 (1H, ddd, 12.0, 5.0, 1.5, H-4ꢀ), 1.73 (1H, q, 12.0, H-
4ꢀ), 1.59 (overlapping, H-8), 1.58 (overlapping, H-4), 1.38 (overlapping, H-
5), 1.28 (overlapping, H-1), 0.89 (3H, s, H-18).
Experimental
General Procedure The instrumental analysis was carried out as de-
scribed previously.27) Melting points were measured on a Yanaco MP-S3.
X-Ray Analysis Suitable colorless crystals of 20 were obtained by re-
crystallization (CHCl3–MeOH). The crystal (0.40ꢃ0.40ꢃ0.40 mm) be-
longed to the orthorhombic system, space group P212121(#19), with aꢂ
14.461(8) Å, bꢂ30.606(3) Å, cꢂ5.857(6) Å, Vꢂ2592(4) Å3, Zꢂ4. All meas-
urements were made on a Rigaku AFC7R diffractometer with graphite
monochromated CuKa radiation and a rotating anode generator. The struc-
ture was solved by direct methods28) and expanded using Fourier tech-
niques.29) The oxygen atom of the formyl group at C-19 adopted two posi-
tions, and the occupying parameters of this atom were also refined.
Plant Materials The aerial parts of Asclepias curassavica L. were col-
lected from the botanical garden of the University of Shizuoka in Japan in
September, 2001 and identified by Dr. T. Warashina. The dried materials
were stored in a herbarium.
Extraction and Isolation The dried aerial parts of Asclepias curassav-
ica L. (6.8 kg) were treated three times with MeOH under reflux. The extract
was concentrated under reduced pressure and the residue was suspended in
H2O. This suspension was extracted with Et2O. The H2O layer of the MeOH
extract was passed through a porous polymer gel (Mitsubishi Diaion HP-20)
column with the absorbed material being eluted with MeOH–H2O (1 : 1),
MeOH–H2O (7 : 3) and MeOH, respectively. The MeOH fraction from the
porous polymer gel column was then evaporated dry, with the residue
(13.7 g) subjected to silica gel CC with a CHCl3–MeOH (95 : 5—85 : 15)
system and semi-preparative HPLC (Develosil-ODS, and YMC-ODS: 27—
35% MeCN in water and 45—60% MeOH in water) to give compounds 1
(60 mg), 2 (5 mg), 3 (11 mg), 4 (8 mg), 5 (31 mg), 6 (6 mg), 7 (16 mg), 8
(3 mg), 9 (35 mg), 10 (21 mg), 11 (35 mg), 12 (4 mg), 13 (21 mg), 14
(42 mg), 15 (40 mg), 16 (8 mg), 17 (275 mg), 18 (16 mg), 19 (6 mg), 20
(9 mg), 21 (4 mg), 22 (28 mg), 23 (73 mg), 24 (6 mg), 25 (3 mg), 26 (4 mg),
27 (11 mg) and 28 (4 mg). However, compound 28 was not purified com-
pletely.
Calactinolactone (20): Prism from CHCl3–MeOH, mp 301—306 °C. [a]D22
ꢁ56° (cꢂ0.52, CHCl3–MeOH (1 : 1)). FAB-MS m/z: 531 [MꢁH]ꢁ. HR-
FAB-MS m/z: 531.2569 (Calcd for C29H39O9: 531.2594). 13C-NMR: shown
in Table 1. 1H-NMR (pyridine-d5 at 35 °C) d: 10.19 (1H, s, H-19), 6.11 (1H,
br t, 1.5, H-22), 5.63 (1H, s, H-1ꢀ), 5.56 (1H, td, 12.0, 5.0, H-2), 5.25 (1H,
dd, 18.0, 1.5, H-21), 5.00 (1H, dd, 18.0, 1.5, H-21), 4.52 (1H, dquint, 9.5,
6.0, H-5ꢀ), 3.93 (1H, td, 12.0, 4.0, H-3), 2.85 (1H, dd, 12.0, 5.0, H-1), 2.74
(1H, dd, 9.0, 5.0, H-17), 2.64 (1H, dd, 13.5, 9.5, H-4ꢀ), 2.61 (1H, dd, 13.5,
6.0, H-4ꢀ), 1.91 (1H, q, 12.0, H-4), 1.91 (overlapping, H-8), 1.73 (1H, dt,
12.0, 4.0, H-4), 1.40 (overlapping, H-5), 1.36 (3H, d, 6.0, H-6ꢀ), 1.23 (1H, t,
12.0, H-1), 0.92 (3H, s, H-18).
(8R,7ꢀS,8ꢀR)-5,5ꢀ-Dimethoxylariciresinol 9ꢀ-O-b-D-(6-O-E-4-Hydroxy-3-
methoxy-cinnamoyl)-glucopyranoside (23): Amorphous powder. [a]D22 ꢁ15.6°
MeOH
19-Dihydroasclepin (12): Amorphous powder. [a]D22 ꢁ17° (cꢂ0.37,
MeOH). FAB-MS m/z: 599 [MꢁNa]ꢁ. HR-FAB-MS m/z: 599.2806 (Calcd
for C31H44O10Na: 599.2832). 13C-NMR (pyridine-d5 at 35 °C): shown in
(cꢂ1.24, MeOH). UV l
nm (log e): 209 (4.71), 233 (4.26), 284 (sh),
max
299 (sh), 326 (4.12). FAB-MS m/z: 758 [M]ꢁ, 781 [MꢁNa]ꢁ. HR-FAB-MS
m/z: 758.2776 (Calcd for C38H46O16: 758.2786). 13C- and H-NMR: shown
1
1
in Table 2.
Table 1. H-NMR (pyridine-d5 at 35 °C) d: 6.10 (1H, br t, 1.5, H-22), 5.75
(8R,7ꢀS,8ꢀR)-5,5ꢀ-Dimethoxylariciresinol 9ꢀ-O-b-D-(6-O-Z-4-Hydroxy-3-
(1H, br t, 3.0, C-19-OH), 5.45 (1H, dd, 12.0, 5.0, H-3ꢀ), 5.28 (1H, dd, 18.5,
1.5, H-21), 5.08 (1H, s, H-1ꢀ), 5.01 (1H, dd, 18.5, 1.5, H-21), 4.90 (1H, ddd,
12.0, 11.0, 5.0, H-2), 4.46 (1H, td, 11.0, 5.0, H-3), 4.01 (1H, dd, 11.5, 3.0,
H-19), 3.79 (1H, m, H-5ꢀ), 3.74 (1H, dd, 11.5, 3.0, H-19), 2.94 (1H, dd,
12.0, 5.0, H-1), 2.76 (1H, dd, 9.0, 5.0, H-17), 1.78 (3H, s, C-3ꢀ-OCOCH3*),
1.37 (3H, d, 6.0, H-6ꢀ), 1.11 (1H, t, 12.0, H-1), 1.00 (3H, s, H-18).
methoxycinnamoyl)-glucopyranoside (24): Amorphous powder. [a]D22 ꢁ6.2°
MeOH
(cꢂ0.59, MeOH). UV l
nm (log e): 210 (4.67), 230 (sh), 282 (3.87),
max
324 (4.04). FAB-MS m/z: 758 [M]ꢁ, 781 [MꢁNa]ꢁ. HR-FAB-MS m/z:
781.2711 (Calcd for C38H46O16Na: 781.2684). 13C-NMR (MeOH-d4 at
35 °C) d: 168.1 (C-9ꢄ), 149.6 (C-4ꢄ), 148.4 (C-3ꢄ), 145.5 (C-7ꢄ), 128.1 (C-1ꢄ),
126.7 (C-6ꢄ), 116.2 (C-8ꢄ), 115.8 (C-5ꢄ), 115.3 (C-2ꢄ), 56.5 (-OMeꢄ). The
13C-NMR spectroscopic data of the aglycone and sugar moieties were in
good agreement with those of 23. 1H-NMR (MeOH-d4 at 35 °C) d: 7.68
(1H, d, 2.0, H-2ꢄ), 7.11 (1H, dd, 8.0, 2.0, H-6ꢄ), 6.80 (1H, d, 13.0, H-7ꢄ),
19-Nor-16a-acetoxy-10b-hydroxyasclepin (18): Amorphous powder. [a]D22
ꢁ
3.0° (cꢂ0.60, MeOH). FAB-MS m/z: 621 [MꢁH]ꢁ, 643 [MꢁNa]ꢁ. HR-
FAB-MS m/z: 621.2902 (Calcd for C32H45O12: 621.2911). 13C-NMR (pyri-
1
dine-d5 at 35 °C): shown in Table 1. H-NMR (pyridine-d5 at 35 °C) d: 6.28
6.75 (1H, d, 8.0, H-5ꢄ), 5.73 (1H, d, 13.0, H-8ꢄ), 4.49 (1H, dd, 12.0, 2.0, Hglc
-
(1H, br t, 1.5, H-22), 5.84 (1H, br s, C-14-OH), 5.68 (1H, td, 8.0, 4.0, H-16),
5.42 (1H, dd, 12.0, 5.0, H-3ꢀ), 5.29 (1H, s, C-10-OH), 5.29 (1H, dd, 18.0,
1.5, H-21), 5.17 (1H, dd, 18.0, 1.5, H-21), 5.07 (overlapping, H-2), 5.07
(1H, s, H-1ꢀ), 4.48 (1H, ddd, 11.5, 10.0, 4.0, H-3), 3.79 (1H, m, H-5ꢀ), 2.94
(1H, d, 4.0, H-17), 2.55 (1H, dd, 13.5, 8.0, H-15), 2.49 (1H, dd, 12.0, 4.5, H-
1), 2.22 (1H, td, 11.5, 3.0, H-8), 2.11 (1H, q, 12.0, H-4ꢀ), 2.09 (3H, s, C-3ꢀ-
OCOCH3*), 1.87 (3H, s, C-16-OCOCH3*), 1.50 (1H, t, 12.0, H-1), 1.39
(overlapping, H-5), 1.35 (3H, d, 6.5, H-6ꢀ), 1.00 (3H, s, H-18). 13C-NMR
(CDCl3 at 35 °C) d: 174.2 (C-23), 172.3 (C-3ꢀ-OC*OCH3), 171.0 (C-20),
170.7 (C-16-OC*OCH3), 118.4 (C-22), 96.2 (C-1ꢀ), 90.9 (C-2ꢀ), 84.7 (C-
14), 78.4 (C-16), 75.6 (C-3ꢀ), 73.8 (C-21), 73.0 (C-10), 71.5 (C-3), 68.9 (C-
2), 67.8 (C-5ꢀ), 57.8 (C-17), 48.8 (C-13), 47.9 (C-9), 43.5 (C-5), 40.9 (C-8),
39.7, 39.6 (C-1, -12), 39.3 (C-15), 35.5 (C-4ꢀ), 31.6 (C-4), 27.3 (C-6), 26.5
(C-7), 21.1, 21.0 (C-16-OCOC*H3, -3ꢀ-OCOC*H3), 20.9, 20.8 (C-11, -6ꢀ),
6), 4.31 (1H, dd, 12.0, 6.5, Hglc-6), 4.29 (1H, d, 8.0, Hglc-1), 3.83 (3H, s,
-
OMeꢄ), 3.50 (1H, m, Hglc-5), 3.38 (1H, t, 8.0, Hglc-3), 3.33 (1H, t, 8.0, Hglc-
4), 3.23 (1H, t, 8.0, Hglc-2). The 1H-NMR spectroscopic data of the aglycone
moiety were in good agreement with those of 23. But, the signals due to H-
7ꢀ and H-9ꢀ were observed as follows: d 4.80 (1H, d, 6.5, H-7ꢀ), 3.95 (1H,
dd, 10.0, 6.0, H-9ꢀ), 3.80 (overlapping, H-9ꢀ).
(8R,7ꢀS,8ꢀR)-5,5ꢀ-Dimethoxylariciresinol 9ꢀ-O-b-D-(6-O-E-4-Hydroxycin-
namoyl)-glucopyranoside (25): Amorphous powder. [a]D21 ꢁ18° (cꢂ0.26,
MeOH
MeOH). UV l
nm (log e): 207 (4.90), 222 (sh), 312 (4.26). FAB-MS
max
m/z: 751 [MꢁNa]ꢁ. HR-FAB-MS m/z: 751.2572 (Calcd for C37H44O15Na:
751.2578). 13C-NMR (MeOH-d4 at 35 °C) d: 169.0 (C-9ꢄ), 161.4 (C-4ꢄ),
146.8 (C-7ꢄ), 131.2ꢃ2 (C-2ꢄ, -6ꢄ), 127.0 (C-1ꢄ), 116.9ꢃ2 (C-3ꢄ, -5ꢄ), 114.9
1
(C-8ꢄ). H-NMR (MeOH-d4 at 35 °C) d: 7.57 (1H, d, 16.0, H-7ꢄ), 7.34 (2H,
1
d, 8.5, H-2ꢄ, -6ꢄ), 6.76 (2H, d, 8.5, H-3ꢄ, -5ꢄ), 6.28 (1H, d, 16.0, H-8ꢄ). The
13C- and 1H-NMR spectroscopic data of the aglycone and sugar moieties
were in good agreement with those of 23.
15.6 (C-18). H-NMR (CDCl3 at 35 °C) d: 5.94 (1H, br t, 1.5, H-22), 5.27
(1H, td, 8.0, 4.0, H-16), 4.92 (1H, dd, 18.0, 1.5, H-21), 4.85 (1H, dd, 18.0,
1.5, H-21), 4.79 (1H, dd, 12.0, 5.0, H-3ꢀ), 4.59 (1H, s, H-1ꢀ), 4.22 (1H, ddd,
12.0, 10.0, 4.5, H-2), 3.97 (1H, td, 10.0, 5.0, H-3), 3.70 (1H, m, H-5ꢀ), 2.64
(1H, d, 4.0, H-17), 2.25 (1H, dd, 13.5, 8.0, H-15), 2.15 (3H, s, C-3ꢀ-
(8R,7ꢀS,8ꢀR)-5,5ꢀ-Dimethoxylariciresinol 9ꢀ-O-b-D-(6-O-E-4-Hydroxy-
3,5-dimethoxycinnamoyl)-glucopyranoside (26): Amorphous powder. [a]D21

August 2008
17° (cꢂ0.32, MeOH). UV l
1163
MeOH
max
and 26, respectively. cis-Ferulic acid was yielded from compounds 24 and
28. Similarly, compounds 23a and 27a were detected from the H2O layers
derived from compounds 24—26 and 28 using HPLC. HPLC conditions:
column, YMC-ODS 4.6 mmꢃ25 cm; flow rate, 1.0 ml/min; solvent, 35%
MeOH in water; tR 16.6 min (23a), 18.2 min (27a).
ꢁ
nm (log e): 212 (5.25), 233 (sh), 283
(sh), 327 (4.26). FAB-MS m/z: 788 [M]ꢁ, 811 [MꢁNa]ꢁ. HR-FAB-MS m/z:
788.2900, 811.2793 (Calcd for C39H48O17: 788.2892 and C39H48O17Na:
811.2789). 13C-NMR (MeOH-d4 at 35 °C) d: 168.9 (C-9ꢄ), 149.5ꢃ2 (C-3ꢄ,
-5ꢄ), 147.3 (C-7ꢄ), 139.8 (C-4ꢄ), 126.6 (C-1ꢄ), 115.7 (C-8ꢄ), 107.0ꢃ2 (C-2ꢄ,
1
-6ꢄ), 56.8ꢃ2 (-OMeꢄ). H-NMR (MeOH-d4 at 35 °C) d: 7.57 (1H, d, 16.0,
References
H-7ꢄ), 6.82 (2H, s, H-2ꢄ, -6ꢄ), 6.37 (1H, d, 16.0, H-8ꢄ), 3.82 (6H, s, -OMeꢄ).
1
The 13C- and H-NMR spectroscopic data of the aglycone and sugar moi-
1) Abe F., Mohri Y., Yamauchi T., Chem. Pharm. Bull., 39, 2709—2711
(1991).
eties were in good agreement with those of 23.
2) Abe F., Mohri Y., Yamauchi T., Chem. Pharm. Bull., 40, 2917—2920
(1992).
3) Roy M. C., Chang F.-R., Huang H.-S., Chiang M. Y.-N., Wu Y.-C., J.
Nat. Prod., 68, 1494—1499 (2005).
4) Brower L. P., Brower J. V. Z., Corvino J. M., Proc. Natl. Acad. Sci.
U.S.A., 57, 893—898 (1967).
(8R,7ꢀS,8ꢀR)-5ꢀ-Methoxylariciresinol 9ꢀ-O-b-D-(6-O-E-4-Hydroxy-3-
methoxy-cinnamoyl)-glucopyranoside (27): Amorphous powder. [a]D21
ꢁ15.3° (cꢂ1.08, MeOH). UV lmMaexOH nm (log e): 209 (4.55), 229 (4.28), 288
(4.02), 326 (4.15). FAB-MS m/z: 728 [M]ꢁ, 751 [MꢁNa]ꢁ. HR-FAB-MS
m/z: 728.2666, 751.2584 (Calcd for C37H44O15: 728.2680 and C37H44O15Na:
751.2578). 13C- and 1H-NMR: shown in Table 2.
5) Brower L. P., Ryerson W. N., Coppinger L. L., Glazier S. C., Science,
161, 1349—1350 (1968).
6) Brower L. P., (Ecological Chemistry), Scientific American, 220, 22—
29 (1969).
7) Ranraswami S., Reichstein T., Helv. Chim. Acta, 32, 939—949 (1949).
8) Mitsuhashi H., Hayashi K., Tomimoto K., Chem. Pharm. Bull., 18,
828—831 (1970).
9) El-Askary H., Holzl J., Hilal S., El-Kashoury E., Phytochemistry, 34,
1399—1402 (1993).
(8R,7ꢀS,8ꢀR)-5ꢀ-Methoxylariciresinol 9ꢀ-O-b-D-(6-O-Z-4-Hydroxy-3-
methoxy-cinnamoyl)-glucopyranoside (28): FAB-MS m/z: 728 [M]ꢁ, 751
[MꢁNa]ꢁ. HR-FAB-MS m/z: 728.2677, 751.2577 (Calcd for C37H44O15:
728.2680 and C37H44O15Na: 751.2578). The 13C- and 1H-NMR spectra of 28
were measured in MeOH-d4 solution. Its spectroscopic data of the aglycone
moiety were in good agreement with those of 27, but, the signals due to H-
7ꢀ and H-9ꢀ were observed as follows: d 4.81 (1H, d, 6.5, H-7ꢀ), 3.94 (1H,
dd, 10.0, 6.0, H-9ꢀ), 3.79 (overlapping, H-9ꢀ). The data of the sugar and ester
moieties were similar to those of 24.
10) Poloria J., Kuritskes A., Jager H., Reichstein T., Helv. Chim. Acta, 42,
1437—1447 (1959).
11) Tschesche R., Freytag U., Snatzke G., Chem. Ber., 92, 3053—3063
(1959).
12) Sierp von D., Stocklin W., Reichstein T., Helv. Chim. Acta, 53, 27—47
(1970).
13) Cheung H. T. A., Nelson C. J., Watson T. R., J. Chem. Soc., Perkin
Trans. 1, 1988, 1851—1857 (1988).
14) Martin R. A., Lynch S. P., Schmitz F. J., Pordesimo E. O., Toth S., Hor-
ton R. Y., Phytochemistry, 30, 3935—3939 (1991).
15) Rodriguez-Hahn L., Fonseca G., Phytochemistry, 30, 3941—3942
(1991).
16) Warashina T., Noro T., Phytochemistry, 37, 801—806 (1994).
17) Bruschweiler F., Stocklin W., Stockel K., Reichstein T., Helv. Chim.
Acta, 52, 2276—2303 (1969).
Alkaline Hydrolysis of Compounds 23 and 27 Compounds 23 (12 mg)
and 27 (11 mg) were each dissolved in 0.25 M NaOH (1.0 ml). The solution
was stirred for 1.5 h at room temperature under a N2 atmosphere. The reac-
tion mixture was passed through an Amberlite IR-120B column with the
eluate concentrated dry. The residue was partitioned between EtOAc and
H2O. Both layers were concentrated dry, and HPLC of the residue from each
EtOAc layer suggested that trans-ferulic acid was produced from 23 and 27.
HPLC conditions: column, YMC-ODS 4.6 mmꢃ25 cm; flow rate 1.0 ml/
min; solvent, 20% MeCN in waterꢁ0.05% trifluoroacetic acid (TFA); tR
15.2 min (trans-ferulic acid). Purification of the residue from each H2O layer
using HPLC afforded 23a (3 mg) and 27a (6 mg). HPLC conditions: column,
YMC-ODS 10 mmꢃ25 cm; flow rate, 3.0 ml/min; solvent, 23a, 35% MeOH
in water, 27a, 32.5% MeOH in water. Compounds 23a and 27a were identi-
fied to be (8R,7ꢀS,8ꢀR)-5,5ꢀ-dimethoxylariciresinol 9ꢀ-O-b-D-glucopyrano-
side (alangilignoside C) and (8R,7ꢀS,8ꢀR)-5ꢀ-methoxylariciresinol 9ꢀ-O-b-D-
1
18) Cheung H. T. A., Watson T. R., J. Chem. Soc., Perkin Trans. 1, 1980,
2162—2168 (1980).
glucopyranoside (alangilignoside D), respectively, on the basis of the H-,
13C-NMR spectroscopic data, optical rotation values and CD spectral
data.24,25)
19) Cheung H. T. A., Chiu F. C. K., Watson T. R., Wells R. J., J. Chem.
Soc., Perkin Trans. 1, 1983, 2827—2835 (1983).
20) Lee S. M., Seiber J. N., Phytochemistry, 22, 923—927(1983).
21) Cheung H. T. A., Nelson C. J., J. Chem. Soc., Perkin Trans. 1, 1989,
1563—1570 (1989).
22) Warashina T., Noto T., Phytochemistry, 37, 217—226 (1994).
23) Abe F., Yamauchi T., Phytochemistry, 27, 575—577 (1988).
24) Yuasa K., Ide T., Otsuka H., Ogimi C., Hirata E., Takushi A., Takeda
Y., Phytochemistry, 45, 611—615 (1997).
25) Achenbach H., Benirschke M., Torrenegra R., Phytochemistry, 45,
325—335 (1997).
26) Warashina T., Noro T., Chem. Pharm. Bull., 56, 315—322 (2008).
27) Warashina T., Nagatani Y., Noro T., Phytochemistry, 65, 2003—2011
(2004).
28) Altomare A., Cascarano G., Giacovazzo C., Guagliardi A., Burla M.,
Polidori G., Camalli M., J. Appl. Cryst., 27. 435—436 (1994).
29) Beurskens P., Admiraal G., Beurslens G., Bosman W., Del Gelder R.,
Israel R., Smits J. M. M., “The DIRDIF-99 Program System, Technical
Report of the Crystallography Laboratory,” University of Nijimegem,
The Netherlands, 1999.
Compound 23a: Amorphous powder. [a]D21 ꢁ12° (cꢂ0.29, MeOH). UV
MeOH
l
nm (log e): 207 (5.06), 232 (sh), 270 (3.35). CD nm (De): 242
max
(ꢆ1.38), 278 (ꢁ0.156) (cꢂ0.51 mg/ml MeOH). [lit.: [a]D24 ꢁ16.2° (cꢂ0.74,
MeOH
MeOH). UV l
nm (log e): 209 (4.80), 234 (4.12), 273 (3.45). CD nm
max
(De): 211 (ꢁ11.1), 244 (ꢆ1.14): [a]D ꢁ18° (cꢂ0.4, MeOH). UV lmMaexOH nm
(log e): 208 (4.95), 237 (4.24), 271 (3.52). CD nm (De): 245 (ꢆ0.28), 278
(ꢁ0.12)].24,25)
Compound 27a: Amorphous powder. [a]D21 ꢁ13° (cꢂ0.57, MeOH). UV
MeOH
max
l
nm (log e): 207 (5.08), 228 (sh), 280 (3.57). CD nm (De): 239
(ꢆ1.27), 260 (ꢁ0.248), 288 (ꢆ0.331) (cꢂ0.61 mg/ml MeOH). [lit.: [a]D24
ꢁ10.3° (cꢂ0.87, MeOH). UV lmMaexOH nm (log e): 207 (4.69), 228 (4.14), 281
(3.61). CD nm (De): 208 (ꢁ7.13), 239 (ꢆ0.73)].24)
Alkaline Hydrolysis of Compounds 24—26 and 28 Solutions of com-
pounds 24—26 and 28 (ca. 0.5 mg) in 0.25 M NaOH (1.0 ml) were stirred for
1 h at room temperature under a N2 atmosphere. The procedures and condi-
tions for the detection of the component ester were described above. HPLC
conditions: column, YMC-ODS 4.6 mmꢃ25 cm; flow rate, 1.0 ml/min; sol-
vent, 20% MeCN in waterꢁ0.05% TFA; tR 13.2 min (trans-p-coumaric
acid), 14.6 min (trans-sinapinic acid), 17.6 min (cis-ferulic acid). trans-p-
Coumaric acid and trans-sinapinic acid were afforded from compounds 25