Triterpenoid saponins of Acanthopanax nipponicus leaves

Article abstract of DOI:10.1021/np9804334

Five new triterpenoid saponins, nipponosides A-E (1, 3-6), were isolated from Acanthopanax nipponicus leaves, along with a known saponin, kalopanaxsaponin G (2). Nipponosides A-E were characterized as the 28-O-α- L-rhamnopyranosyl(1-4)-β-D-glucopyranosyl(16)-β-D-glucopyranosyl ester of 3-oxohederagenin, oleanolic acid 3-O-β-D-glucopyranoside, gypsogenin 3-O- β-D-glucopyranoside, 3β,23,29-trihydroxyolean-12-en-28-oic acid, and 3β,20α,23-trihydroxy-30-nor-olean-12-en-28-oic acid, respectively. The structures of these new compounds were based on chemical and spectral methods.

Full text of DOI:10.1021/np9804334

J . Nat. Prod. 1999, 62, 445-448
445
Tr iter p en oid Sa p on in s of Aca n th opa n a x n ippon icu s Lea ves
Masazumi Miyakoshi,† Katsuya Shirasuna,† Yasuaki Hirai,† Kazushi Shingu,† Susumu Isoda,† J unzo Shoji,†
Yoshiteru Ida,*,† and Torao Shimizu‡
School of Pharmaceutical Sciences, Showa University, Hatanodai 1-5-8, Shinagawa-ku, Tokyo 142-8555, J apan, and
Tokyo Metropolitan Medicinal Plant Garden, Nakajima-cho 21-1, Kodaira, Tokyo 187-0033, J apan
Received October 2, 1998
Five new triterpenoid saponins, nipponosides A-E (1, 3-6), were isolated from Acanthopanax nipponicus
leaves, along with a known saponin, kalopanaxsaponin G (2). Nipponosides A-E were characterized as
the 28-O-R-L-rhamnopyranosyl(1f4)-â-D-glucopyranosyl(1f6)-â-D-glucopyranosyl ester of 3-oxoheder-
agenin, oleanolic acid 3-O-â-D-glucopyranoside, gypsogenin 3-O-â-D-glucopyranoside, 3â,23,29-trihydroxy-
olean-12-en-28-oic acid, and 3â,20R,23-trihydroxy-30-nor-olean-12-en-28-oic acid, respectively. The
structures of these new compounds were based on chemical and spectral methods.
There are nine species belonging to the genus Acantho-
panax (Araliaceae) in J apan, namely, A. divaricatus (Sieb.
et Zucc.) Seemann, A. hypoleucus Makino, A. sciadophyl-
loides Franch. et Savat, A. senticosus (Rupr. et Maxim.)
Harms, A. sieboldianus Franch. et Savat, A. spinosus Miq.,
A. trichodon Franch. et Savat., A. nikaianus Koidz., and
A. nipponicus Makino.1 We have investigated the constitu-
ents of the leaves of the first seven of these species and
have found that they may be classified into three groups
according to their saponin constituents or lack thereof. The
first group produces oleanane saponins exclusively and
comprises A. hypoleucus,2 A. senticosus,3,4 A. sieboldianus,5
and A. spinosus.6-8 The second group, constituted by A.
divaricatus, has no oleanane saponins but accumulates
lupane saponins.9,10 The species in the third group, A.
sciadophylloides 11 and A. trichodon,12 contain no saponins
at all. Herein, we describe a phytochemical investigation
from a chemotaxonomic point of view, which has led to the
isolation and the characterization of six oleanane saponins
from A. nipponicus.
molecular ion ([M - H]-) by loss of the ester-linked RGG
moiety (470 atomic mass units (amu)).
Compound 1 (nipponoside A) exhibited in the negative
FABMS prominent ion peaks at m/z 939 and 469, each 2
amu smaller than those of 2. The 13C NMR spectrum of 1
showed 48 carbon signals, 18 of which were assignable to
13
the RGG carbons at C-28 (Table 1) on comparison of the
13C NMR spectrum of 2. The remaining 30 signals were
similar to those due to a hederagenin moiety of 2, except
for four carbons, which were assigned to C-2, C-3, C-4, and
C-24 using 1H-1H COSY, HMQC, and HMBC experiments.
Among them, a signal appearing at δ 216.9 was ascribable
to a carbonyl carbon instead of the C-3 carbinyl carbon
signal (δ 73.9) of hederagenin. Thus, the aglycon of 1 was
assumed to be 3-oxohederagenin (8). Finally, the 30 carbon
signals were found to be superimposable on those of
3-oxohederagenin methyl ester (8a ).15 On reduction with
sodium borohydride in methanol at room temperature, 1
provided 2. Thus, nipponoside A (1) was deduced to be
3-oxohederagenin 28-O-R-L-rhamnopyranosyl(1f4)-â-D-
glucopyranosyl(1f6)-â-D-glucopyranoside. This is the first
example of a 3-oxohederagenin glycoside from a natural
source.
Resu lts a n d Discu ssion
Compounds 1-6 were isolated from the crude saponin
mixture obtained from A. nipponicus leaves, as described
in the Experimental Section. Of these, 2 was identified as
kalopanaxsaponin G [hederagenin 28-O-R-L-rhamnopyra-
nosyl(1f4)-â-D-glucopyranosyl(1f6)-â-D-glucopyrano-
side], previously isolated in this laboratory from the
stembark of Kalopanax pictus (Araliaceae).13
Compounds 1 and 3-6 were found to have several
chemical and physical properties similar to 2. Thus, they
afforded glucose (Glc) and rhamnose (Rha) as their sugar
components on acidic hydrolysis and provided an anomeric
mixture of methyl R-L-rhamnopyranosyl(1f4)-â-D-glucopy-
ranosyl(1f6)-R- and â-D-glucopyranosides (7) on the selec-
tive cleavage reaction of the C-28 glycoside linkage with
lithium iodide and methanol in 2,6-lutidine.2,14 Their 13C
NMR spectral data showed 18 signals due to the C-28
linked R-L-rhamnopyranosyl(1f4)-â-D-glucopyranosyl(1f6)-
â-D-glucopyranosyl (RGG) carbons and the C-28 signal as
an ester linkage (δ 176.3-176.5).13 Furthermore, their
negative FABMS data exhibited an ion peak due to the
fragment ion ([M - H - 470]-) resulting from the pseudo-
Compound 3 (nipponoside B) exhibited in the FABMS
ion peaks at m/z 1087 and 617, but no fragment peak
corresponding to the aglycon. The 13C NMR spectrum of 3
indicated 54 signals, of which 24 were assigned to the â-D-
glucopyranosyl2 and ester-linked RGG carbons (Table 1).
On a selective cleavage reaction of the C-28 glycosyl
linkage, 3 gave a prosapogenin (3a ) along with 7. The
prosapogenin 3a , still containing a â-D-glucopyranosyl
unit,13 afforded glucose and oleanolic acid on acidic hy-
drolysis. Accordingly, 3a was established as oleanolic acid
3-O-â-D-glucopyranoside. Thus, nipponoside B (3) was
established as 3-O-â-D-glucopyranosyl oleanolic acid 28-O-
R-L-rhamnopyranosyl(1f4)-â-D-glucopyranosyl(1f6)-â-D-
glucopyranoside.
Compound 4 (nipponoside C) showed FABMS ion peaks
at m/z 1101 and 631, each 14 amu larger than those of 3.
The 13C NMR spectrum of 4 showed 47 carbon signals,
which were similar to those of 3 except for five signals
assignable to C-3, C-4, C-5, C-23, and C-24. Among them,
a signal at δ 206.9 was ascribable to an aldehyde carbon
instead of the C-23 methyl carbon signal (δ 28.2) in the
case of 3 (Table 1). The 30 signals due to the aglycon moiety
were found to be superimposable on those reported for the
gypsogenin moiety in its 3,28-O-bisdesmoside, thladioside
* To whom correspondence should be addressed. Tel.: (81) 3-3784-8189.
Fax: (81) 3-3784-8191. E-mail: ida@pharm.showa-u.ac.jp.
† Showa University.
‡ Tokyo Metropolitan Medicinal Plant Garden.
10.1021/np9804334 CCC: $18.00
© 1999 American Chemical Society and American Society of Pharmacognosy
Published on Web 02/27/1999

446 J ournal of Natural Products, 1999, Vol. 62, No. 3
Miyakoshi et al.
a
Ta ble 1. 13C NMR Signals of Saponins 1-6, 3a , 5a , and 8 in Pyridine-d5
carbon
1
2
3
4
5
6
8b
3a
5a
C-1
C-2
C-3
C-4
C-5
C-6
C-7
C-8
36.3
37.9
216.9
52.7
46.7
20.0
32.2
39.8
47.1
36.6
23.9
122.8
144.1
42.3
28.3
23.4
47.1
41.8
46.2
30.4
34.0
32.5
68.1
17.9
15.4
17.3
25.8
176.5
33.1
23.7
38.9
27.7
73.9
42.9
48.7
18.7
32.6
40.0
48.2
37.3
23.7
123.0
144.2
42.2
28.4
23.9
47.1
41.7
46.3
30.8
34.1
33.1
68.1
13.1
16.1
17.7
26.1
176.5
33.0
23.7
38.7
26.6
88.9
39.5
55.8
18.5
33.1
39.9
48.0
37.0
23.8
122.9
144.1
42.1
28.3
23.4
47.0
41.7
46.2
30.7
34.0
32.5
28.2
17.2
15.6
17.5
26.1
176.5
33.9
23.7
38.1
25.0
81.6
55.4
47.9
20.4
32.3
40.1
47.6
36.0
23.6
122.5
144.1
41.6
28.2
23.2
46.9
42.1
46.1
30.7
33.9
32.4
206.9
10.3
15.6
17.4
26.0
176.4
33.0
23.6
38.8
27.6
73.8
42.8
48.6
18.6
32.8
39.8
48.1
37.2
23.8
122.9
144.3
42.1
28.3
23.4
47.4
41.1
40.9
36.3
28.8
32.0
68.0
13.0
16.0
17.6
26.0
176.5
73.6
19.7
38.8
27.6
73.8
42.8
48.5
18.6
32.8
39.9
48.1
37.1
23.7
123.0
143.6
42.1
28.2
23.5
47.0
44.0
47.8
69.6
35.9
34.4
67.8
13.0
16.0
17.5
25.9
176.3
25.6
36.3
37.8
216.8
52.7
46.5
19.9
32.2
39.6
47.2
36.6
23.6
122.6
144.1
42.1
28.0
23.8
47.0
41.9
46.0
30.8
33.9
32.7
68.2
17.9
15.3
17.0
25.9
178.0
33.1
23.7
51.6
38.7
26.5
88.9
39.5
55.8
18.5
33.3
39.7
48.0
37.0
23.8
123.0
145.0
42.2
28.3
23.8
46.7
42.0
46.6
31.0
34.3
33.2
28.3
17.1
15.5
17.4
26.2
180.0
33.3
23.8
38.7
27.6
73.9
42.8
48.7
18.6
32.9
39.7
48.1
37.2
23.8
122.9
145.2
42.2
28.4
23.8
47.2
41.4
41.3
36.6
29.1
32.7
68.1
13.0
15.9
17.5
26.1
180.9
73.5
19.7
C-9
C-10
C-11
C-12
C-13
C-14
C-15
C-16
C-17
C-18
C-19
C-20
C-21
C-22
C-23
C-24
C-25
C-26
C-27
C-28
C-29
C-30
COOMe
3-O-sugar
Glc-C
1
2
3
4
5
6
106.9
75.8
78.3
71.9
78.0
63.1
104.7
75.2
78.6
71.5
78.2
62.8
106.8
75.7
78.6
72.0
78.0
63.0
28-O-sugars
Glc-C
1
2
3
4
5
6
95.7
73.9
78.3
70.9
78.0
69.2
95.7
73.6
78.4
71.0
78.0
69.3
95.6
73.9
78.3
70.9
78.0
69.2
95.6
73.9
78.5
70.8
78.0
69.2
95.6
74.0
78.2
70.8
77.9
69.2
95.7
74.0
78.2
70.8
77.9
69.3
Glc-C
1
2
3
4
5
6
104.9
75.3
76.5
78.7
77.1
61.3
104.9
75.3
76.6
78.8
77.2
61.2
104.8
75.3
76.5
78.7
77.1
61.3
104.8
75.3
76.5
78.7
77.1
61.2
104.9
75.3
76.5
78.7
77.1
61.2
104.9
75.2
76.5
78.7
77.1
61.2
Rha-C
1
2
3
4
5
6
102.7
72.8
72.6
74.0
70.3
18.5
102.8
72.6
72.8
74.1
70.4
18.5
102.7
72.8
72.5
74.0
70.3
18.5
102.7
72.7
72.5
73.8
70.2
18.5
102.7
72.7
72.5
73.5
70.2
18.5
102.7
72.7
72.5
73.4
70.3
18.5
a
The signals were assigned by comparison with data of related compounds. Assignments were confirmed by DEPT, 1H-1H COSY,
HMQC, and HMBC experiments for 1. Data taken from Miyakoshi et al.15
b
H1.16 Thus, nipponoside C (4) was characterized as 3-O-
â-D-glucopyranosyl gypsogenin 28-O-R-L-rhamnopyranosyl-
(1f4)-â-D-glucopyranosyl(1f6)-â-D-glucopyranoside.
The FABMS of 5 (nipponoside D) showed ion peaks at
m/z 957 and 487, both 16 amu greater than analogous data
for 2. The 13C NMR spectrum of 5 was similar to that of 2
except for certain E-ring signals, including a carbinyl
carbon signal at δ 73.5 instead of the 29- or 30-CH3 carbon
signal (δ 33.0 or 23.7, respectively) of 2, suggesting the
aglycon of 5 (5a ) to be 29- or 30-hydroxylated hederagenin.
The E-ring 13C NMR signals of 5 were found to be
coincident with those reported for a 29-hydroxyoleanane
derivative, spinoside C5 (9),7 but not for a 30-hydroxy-
oleanane derivative, spinoside C2 (10).8 Accordingly, the
aglycon of 5 was deduced to be 29-hydroxyhederagenin (i.e.,
3â,23,29-trihydroxyolean-12-en-28-oic acid). Thus, nippono-
side D (5) was assigned as 29-hydroxyhederagenin 28-O-
R-L-rhamnopyranosyl(1f4)-â-D-glucopyranosyl(1f6)-â-D-

Acanthopanax Triterpenoid Saponins
J ournal of Natural Products, 1999, Vol. 62, No. 3 447
glucopyranoside, which is the C-5 epimer of spinoside C5
(9). The aglycon of 5 was a new sapogenol and was named
nipponogenin D.
that a complete chemotaxonomic perspective of the sa-
ponins may be obtained, further investigations on the
remaining J apanese Acanthopanax species, A. nikaianus,
are in progress.
Exp er im en ta l Section
Gen er a l Exp er im en ta l P r oced u r es. Optical rotations
were determined in MeOH on a J ASCO DIP 140 digital
polarimeter at 25 °C. IR spectra were recorded in KBr disks
on a J ASCO IR 810 spectrometer. NMR spectra were recorded
in C5D5N containing TMS as internal standard on a J EOL
J NM GX-400 spectrometer (1H, 400 MHz; 13C, 100 MHz).
Chemical shifts were assigned by means of DEPT and 2D NMR
techniques (1H-1H COSY, HMQC, and HMBC). MS spectra
were obtained on a J EOL J MS SX-102A spectrometer using
glycerol as matrix. GC was carried out on a Shimadzu GC-7A
apparatus equipped with a FID detector and a glass column
(3 mm × 2.1 m) packed with 5% OV-17 at 155 °C. TLC was
carried out on precoated Si gel 60 plates (Merck), and column
chromatography on Si gel 60 (0.063-0.2 mm, Merck), RP-2
(Merck), Sephadex LH-20 (Pharmacia), Chromatorex ODS
(DM-1020T, Fuji-Silysia) or Diaion HP-20 (Mitsubishi Chemi-
cal Corporation).
P la n t Ma ter ia l. The plant was grown at Tokyo Metropoli-
tan Medicinal Plant Garden, Tokyo, J apan, and was collected
in May 1992. A voucher specimen (no. 1996-03) has been
deposited in the Herbarium of the School of Pharmaceutical
Sciences, Showa University, J apan.
Extr a ction a n d Isola tion . The dried leaves (1.35 kg) of
A. nipponicus were extracted with MeOH at room temperature
followed by removal of the solvent by evaporation to give a
dried MeOH extract (155 g). A portion of the extract (50 g)
was suspended in H2O and the suspension partitioned with
Et2O (16.7 g). The H2O layer was chromatographed on Diaion
HP-20, eluting with H2O (12.7 g), 30% MeOH (0.56 g), 70%
MeOH (9.61 g), MeOH (1.32 g), and Me2CO (0.24 g), succes-
sively. The 70% MeOH eluate was chromatographed on Si gel
with CHCl3-MeOH-H2O (70:25:2) to give six fractions: frac-
tions 1 (0.29 g), 2 (2.07 g), 3 (2.57 g), 4 (1.82 g), 5 (0.53 g), and
6 (2.48 g). Fraction 2 was subjected to ODS chromatography
with 60% MeOH to give 1 (0.47 g). Fraction 4 was chromato-
graphed on ODS with 60% MeOH and then on Si gel with
CHCl3-MeOH-H2O (10:5:1) to give 2 (0.13 g). Fraction 6 was
separated by chromatography on Sephadex LH-20 with MeOH,
then Si gel with CHCl3-MeOH-H2O (10:6:1 and 14:6:1) and
finally ODS with 60% MeOH, to give 3 (0.18 g), 4 (0.06 g), 5
(0.21 g), and 6 (0.07 g).
In the FABMS, compound 6 (nipponoside E) exhibited
the presence of ion peaks at m/z 943 and 473, 14 amu
smaller than analogous peaks of 5, suggesting 6 to be a
nortriterpene glycoside related to 5. The 13C NMR spectrum
of 6 showed 47 signals, including those due to the RGG
carbons. The remaining 29 signals were similar to those
of a 29-hydroxyhederagenin moiety except for the signals
due to the carbons around the E-ring. Thus, tertiary
carbinyl carbon signal (δ 69.6) appeared in the 13C NMR
spectrum of 6, while the primary carbinyl C-29 (δ 73.5) and
quaternary C-20 signals (δ 36.3) of 5 were not present,
suggesting the aglycon of 6 to be a 29- or 30-nortriterpene
having a tertiary hydroxyl group at C-20. The 13C NMR
signals in ring E in 6 were found to be superimposable on
those of the 3R,20R,23-trihydroxy-30-nor-olean-12-en-28-
oic acid moiety (20R-hydroxyl-30-nor-3-epi-hederagenin) in
the glycoside, spinoside C6 (11).8 Thus, nipponoside E (6)
was characterized as 20R-hydroxyl-30-nor-hederagenin 28-
O-R-L-rhamnopyranosyl(1f4)-â-D-glucopyranosyl(1f6)-â-
D-glucopyranoside, which is an epimer of spinoside C6 at
C-3. The aglycon of 6, 3â,20R,23-trihydroxy-30-nor-olean-
12-en-28-oic acid (6a ), has been accorded that trivial name,
nipponogenin E.
Nip p on osid e A (1): white powder, [R]25 -1.4° (c 0.50,
D
MeOH); IR (KBr) νmax 3400, 2925, 1740, 1680, 1460, 1390, 1060
cm-1; 1H NMR (C5D5N) δ 0.84, 0.88, 0.93, 1.03, 1.22, 1.22 (3H
each, s, tert-Me), 1.67 (3H, d, J ) 6.2 Hz, Rha H-6), 4.96 (1H,
d, J ) 7.1 Hz, outer Glc H-1), 5.42 (1H, t-like, H-12), 5.81 (1H,
s, Rha H-1), 6.21 (1H, d, J ) 8.1 Hz, 28-O-Glc H-1); 13C NMR
(C5D5N), Table 1; FABMS (negative) m/z 939 [M - H]-, 469
[M - H - 470]-; anal. C 60.55%, H 8.47%, calcd for C48H76O18
‚
(1/2)H2O, C 60.68%, H 8.17%.
Ka lop a n a x Sa p on in G (2): white powder, [R]25 -4.0° (c
D
0.50, MeOH); IR (KBr) νmax 3400, 2925, 1730, 1060, 1040 cm-1
;
1H NMR (C5D5N) δ 0.85, 0.88, 1.00, 1.05, 1.13, 1.17 (3H each,
s, tert-Me), 1.68 (3H, d, J ) 6.2 Hz, Rha H-6), 4.97 (1H, d, J )
7.1 Hz, outer Glc H-1), 5.42 (1H, t-like, H-12), 5.82 (1H, s, Rha
H-1), 6.22 (1H, d, J ) 8.1 Hz, 28-O-Glc H-1); 13C NMR (C5D5N),
Table 1; FABMS (negative) m/z 941 [M - H]-, 471 [M - H -
470]-. The identification was performed by direct comparison
with an authentic specimen.13
Nip p on osid e B (3): white powder, [R]25 -2.7° (c 0.50,
D
MeOH); IR (KBr) νmax 3400, 2925, 1720, 1060, 1030 cm-1; H
1
NMR (C5D5N) δ 0.84, 0.87, 0.88, 0.99, 1.07, 1.23, 1.29 (3H each,
s, tert-Me), 1.67 (3H, d, J ) 6.2 Hz, Rha H-6), 4.90 (1H, 3-O-
Glc H-1, overlapped with HOD), 4.95 (1H, d, J ) 7.1 Hz, outer
Glc H-1), 5.39 (1H, t-like, H-12), 5.81 (1H, s, Rha H-1), 6.20
(1H, d, J ) 7.0 Hz, 28-O-Glc H-1); 13C NMR (C5D5N), Table 1;
In conclusion, six oleanane saponins (1-6) from A.
nipponicus leaves have been isolated and characterized. So

448 J ournal of Natural Products, 1999, Vol. 62, No. 3
Miyakoshi et al.
FABMS (negative) m/z 1087 [M - H]-, 617 [M - H - 470]-;
anal. C 55.98%, H 8.25%, calcd for C54H88O22‚4H2O, C 55.85%,
H 8.33%.
4.07 (1H, dd, J ) 9.0, 7.7 Hz, Glc H-2), 4.28 (1H, dd, J ) 9.0,
9.0 Hz, Glc H-3), 4.33 (1H, dd, J ) 9.0, 9.0 Hz, Glc H-4), 4.46
(1H, dd, J ) 5.1, 11.4 Hz, Glc H-6a), 4.59 (1H, dd, J ) 2.2,
11.4 Hz, Glc-H6b), 4.97 (1H, d, J ) 7.7 Hz, Glc H-1), 5.51(1H,
t-like, H-12); 13C NMR (C5D5N), Table 1; FABMS (negative)
m/z 617 [M - H]-. On acid hydrolysis, 3a gave oleanolic acid
[TLC, n-hexane-Me2CO (2:1), Rf 0.42] and glucose, which were
detected as mentioned above.
Nip p on osid e C (4): white powder, [R]25 -7.0° (c 0.50,
D
MeOH); IR (KBr) νmax 3400, 1720, 1060, 1040 cm-1; H NMR
1
(C5D5N) δ 0.92, 0.96, 0.96, 1.11, 1.28, 1.39 (3H each, s, tert-
Me), 1.76 (3H, d, J ) 6.2 Hz, Rha H-6), 4.89 (1H, d, J ) 7.7
Hz, outer Glc H-1), 5.00 (1H, 3-O-Glc H-1, overlapped with
HOD), 5.46 (1H, t-like, H-12), 5.91 (1H, s, Rha H-1), 6.28 (1H,
d, J ) 7.0 Hz, 28-O-Glc H-1), 9.81 (1H, s, H-23); 13C NMR
(C5D5N), Table 1; FABMS (negative) m/z 1101 [M - H]-, 631
Com p ou n d 5a : white powder, [R]25D +45.1° (c 0.67, C5H5N);
1H NMR (C5D5N) δ 1.05, 1.11, 1.13, 1.29, 1.32 (3H each, s, tert-
Me), 3.78 (1H, d, J ) 10 Hz, H-23a), 4.23 (1H, d, J ) 10 Hz,
H-23b), 4.25 (1H, dd, J ) 5, 10 Hz, H-3), 5.59 (1H, t-like, H-12);
13C NMR (C5D5N), Table 1; FABMS (negative) m/z 487 [M -
H]-.
Na BH4 Red u ction of Nip p on osid e A (1). A solution of 1
(40 mg) and NaBH4 (20 mg) in MeOH (10 mL) was stirred for
20 min at room temperature. After decomposition of excess
reagent with Me2CO (1 mL), the mixture was deionized with
Amberlite MB-3 (H+, OH- form) and concentrated to dryness
in vacuo. The residue was passed through RP-2 eluting with
H2O and MeOH, successively. The MeOH eluates gave the
reduction product of 1 (30 mg), which was identified as 2 by
co-TLC and NMR spectroscopy.
[M - H - 470]-; anal. C 55.89%, H 8.22%, calcd for C54H86O23
‚
3H2O, C 56.04%, H 8.01%.
Nip p on osid e D (5): white powder, [R]25 -4.5° (c 0.61,
D
MeOH); IR (KBr) νmax 3400, 2925, 1740, 1060, 1040 cm-1; H
1
NMR (C5D5N) δ 1.08, 1.13, 1.14, 1.22, 1.26 (3H each, s, tert-
Me), 1.76 (3H, d, J ) 6.2 Hz, Rha H-6), 5.11 (1H, d, J ) 8.1
Hz, outer Glc H-1), 5.53 (1H, t-like, H-12), 5.91 (1H, s, Rha
H-1), 6.32 (1H, d, J ) 8.1 Hz, 28-O-Glc H-1); 13C NMR (C5D5N),
Table 1; FABMS (negative) m/z 957 [M - H]-, 487 [M - H -
470]-; anal. C 59.21%, H 8.57%, calcd for C48H77O19‚H2O, C
59.00%, H 8.16%.
Nip p on osid e E (6): white powder, [R]25 -2.9° (c 0.10,
D
MeOH); IR (KBr) νmax 3400,1740, 1060, 1040 cm-1; H NMR
1
Ack n ow led gm en t. The authors wish to thank the staff
of the Analytical Center of the School of Pharmaceutical
Sciences, Showa University, for the spectral measurement and
for the elemental analysis, and Dr. Satomi Hirai (nee Hirono),
Ms. Yuko Kosaka, and Mr. Takahiro Nakamura for their
technical assistance.
(C5D5N) δ 1.06, 1.12, 1.21, 1.22, 1.52 (3H each, s, tert-Me), 1.76
(3H, d, J ) 6.2 Hz, Rha H-6), 5.56 (1H, t-like, H-12), 5.91 (1H,
s, Rha H-1), 6.31 (1H, d, J ) 8.1 Hz, 28-O-Glc H-1); 13C NMR
(C5D5N), Table 1; FABMS (negative) m/z 943 [M - H]-, 473
[M - H - 470]-; anal. C 57.01%, H 8.22%, calcd for C47H76O19
‚
(5/2)H2O, C 57.01%, H 8.25%.
Id en tifica tion of Su ga r Com p on en ts of 1-6. A solution
of each saponin (a few milligrams) in 1 M HCl in 50% 1,4-
dioxane (2 mL) was heated at 80 °C for 4 h. The reaction
mixture was neutralized with Ag2CO3, filtered, and then
extracted with CHCl3. After concentration, the H2O layer was
examined by TLC with CHCl3-MeOH-H2O (6:4:1) and com-
pared with authentic samples, and glucose (Rf 0.19) and
rhamnose (Rf 0.34) were detected all cases. The sugar compo-
nents in the H2O layer were also analyzed on GLC as TMS
ethers,17 and glucose (tR 20.8, 32.6) and rhamnose (tR 5.9, 7.7)
were also detected.
Refer en ces a n d Notes
(1) Ohwi, J . Flora of J apan (rev. ed.); Shibundo: Tokyo, 1972; pp 964-
967.
(2) Kohda, H.; Tanaka, S.; Yamaoka, Y. Chem. Pharm. Bull. 1990, 38,
3380-3383.
(3) Shao, C.-J .; Kasai, R.; Xu, J .-D.; Tanaka, O. Chem. Pharm. Bull. 1988,
36, 601-608.
(4) Shao, C.-J .; Kasai, R.; Xu, J .-D.; Tanaka, O. Chem. Pharm. Bull. 1989,
37, 42-45.
(5) Sawada, H.; Miyakoshi, M.; Isoda, S.; Ida, Y.; Shoji, J . Phytochemistry
1993, 34, 1117-1121.
(6) Miyakoshi, M.; Ida, Y.; Isoda, S.; Shoji, J . Phytochemistry 1993, 33,
891-895.
Selective Clea va ge of th e Ester Glycosid e Lin k a ges
of 1-6. A solution of 3 (120 mg) and LiI (140 mg) in
2,6-lutidine (8 mL) and dry MeOH (2 mL) was refluxed for 17
h under an N2 atmosphere. After cooling, the reaction mixture
was diluted with 50% MeOH (3 mL), deionized with Amberlite
MB-3 (H+, OH- form), and evaporated to dryness. The residue
was chromatographed on Si gel with CHCl3-MeOH-H2O (14:
6:1) to give 3a (68 mg) and 7 (17 mg), with the latter identified
as a mixture of methyl R-L-rhamnopyranosyl(1f4)-â-D-glu-
copyranosyl(1f6)-R- and â-D-glucopyranosides, respectively,
by direct comparison with an authentic sample.5 In the same
reaction, 3-oxohederagenin (1a ) and nipponogenin E (5a ) were
obtained from 1 and 5, respectively, as their aglycon or
prosapogenin along with 7, whereas 4 and 6 gave 7 as the only
product.
(7) Miyakoshi, M.; Ida, Y.; Isoda, S.; Shoji, J . Phytochemistry 1993, 34,
1599-1602.
(8) Miyakoshi, M.; Isoda, S.; Satoh, H.; Hirai, Y.; Shoji, J .; Ida, Y.
Phytochemistry 1997, 46, 1255-1259.
(9) Matsumoto, K.; Kasai, R.; Kanamaru, F.; Kohda, H.; Tanaka, O.
Chem. Pharm. Bull. 1987, 35, 413-415.
(10) Shirasuna, K.; Miyakoshi, M.; Mimoto, S.; Isoda, S.; Satoh, Y.; Hirai,
Y.; Ida, Y.; Shoji, J . Phytochemistry 1997, 45, 579-584.
(11) Kitajima, J .; Takamori, Y.; Tanaka, Y. Yakugaku Zasshi 1989, 109,
188-191.
(12) Miyakoshi, M.; Terajima, Y.; Isoda, S.; Hirai, Y.; Ida, Y. Nat. Med.
1997, 51, 494.
(13) Sano, K.; Sanada, S.; Ida, Y.; Shoji, J . Chem. Pharm. Bull. 1991, 39,
865-870.
(14) Ohtani, K.; Mizutani, K.; Kasai, R.; Tanaka, O. Tetrahedron Lett.
1984, 25, 4537-4540.
(15) The data for the authentic sample in the literature6 were obtained
in C5D5N.
Com p ou n d 3a : a white powder, [R]25 +20.0° (c 0.10,
D
(16) Nie, R.-L.; Tanaka, T.; Miyakoshi, M.; Kasai, R.; Morita, T.; Zhou,
J .; Tanaka, O. Phytochemistry 1989, 28, 1711-1715.
(17) Sweeley, C. C.; Bentley, R.; Malita, M.; Wells, W. W. J . Am. Chem.
Soc. 1963; 85, 2497-2507.
MeOH); IR (KBr) νmax 3400, 1460, 1380, 1080,1030 cm-1; H
1
NMR (C5D5N) δ 0.86, 0.99, 1.02, 1.04 (3H each, s, tert-Me),
1.34 (9H, s, tert-Me × 3), 3.33 (1H, dd, J ) 3.8, 14.0 Hz, H-18),
3.43 (1H, dd, J ) 4.5, 12.0 Hz, H-3), 4.05 (1H, m, Glc H-5),
NP9804334