Iridoid glucosides from roots of Vietnamese Paederia scandens.

Article abstract of DOI:10.1016/S0031-9422(02)00096-1

Four iridoid glucosides, three of which are dimeric were isolated from the methanol extract of roots of Vietnamese Paederia scandens (Lour) Merrill together with the five known glucosides, paederoside, asperuloside, paederosidic acid, asperulosidic acid and geniposide. Seven sulfur-containing iridoid glucosides were also isolated. The structures of the iridoid glucosides were determined by a combination of high-resolution NMR, MS, IR and UV spectra, and chemical reaction such as acetylation.

Full text of DOI:10.1016/S0031-9422(02)00096-1

Phytochemistry 60 (2002) 505–514
www.elsevier.com/locate/phytochem
Iridoid glucosides from roots of Vietnamese Paederia scandens
Dang Ngoc Quanga, Toshihiro Hashimotoa, Masami Tanakaa,
Nguyen Xuan Dungb, Yoshinori Asakawaa,*
aFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan
bCenter for Education and Development of Chromatography of Vietnam (EDC Vietnam) No. 3 Giai Phong Street, Hai Ba Trung District,
10 000 Hanoi, Viet Nam
Received 10 October 2001; received in revised form 11 February 2002
Abstract
Four iridoid glucosides, three of which are dimeric were isolated from the methanol extract of roots of Vietnamese Paederia
scandens (Lour) Merrill together with the five known glucosides, paederoside, asperuloside, paederosidic acid, asperulosidic acid
and geniposide. Seven sulfur-containing iridoid glucosides were also isolated. The structures of the iridoid glucosides were deter-
mined by a combination of high-resolution NMR, MS, IR and UV spectra, and chemical reaction such as acetylation. # 2002
Elsevier Science Ltd. All rights reserved.
Keywords: Paederia scandens; Rubiaceae; Paederoside; Paederosidic acid; Asperuloside; Asperulosidic acid; Geniposide; Paederosidic acid methyl
ester; Dimeric iridoid glucoside
1. Introduction
that both acids are artifacts (Inouye et al., 1969b,c).
Paederosidic acid methyl ester (3) has also been
obtained by methanolysis of 7 (Inoue et al., 1969c).
In this paper, we report the isolation and structural
elucidation of two newly isolated iridoid glucosides (1, 3)
and three dimeric iridoid glucosides (10, 12, 14), along
with the previously known related compounds (5–9).
Paederia scandens (Lour) Merrill is a climbing plant,
widely grown around Vietnam (Kadota, 2000) and also
in India, China, Japan, Philippines and USA. The
extracts of roots, leaves, bark and fruits are prescribed
for toothache, chest pain, piles, inflammation of the
spleen, diuretic, emetic, rheumatic arthritis and curing
bacillary dysentery (Tran, 1987; Kapadia et al., 1996).
The leaves of this plant are also used in soup and other
food preparation in Vietnam. Until now, paederoside
(5) and asperuloside (6) and their related glucosides,
paederosidic acid (7), deacetylasperuloside and scando-
side have been found in leaves and stem of Paederia
scandens (Inouye et al., 1969a–c, 1988; Shukla et al.,
1976; Kapadia et al., 1979). Sulfur-containing gluco-
sides 5 and 6 from P. scandens exert an inhibitory effect
on Epstein–Barr virus activation (Kapadia et al., 1996).
Inoue et al. (1969b,c) reported that paederosidic acid (7)
and asperulosidic acid (8) were obtained during the
prolonged boiling of an aqueous solution of two lactone
glucosides 5 and 6, respectively and they suggested
2. Results and discussion
The crude methanol extract of Vietnamese P. scandens
(Lour) Merrill was partitioned between butanol and
water. Butanol layer was concentrated in vacuo and pur-
ified using a combination of silica gel column chromato-
graphy and reversed-phase HPLC (C 18) to give a new
iridoid glucosides (1), paederosidic acid methyl ester (3),
which was previously reported as the reaction product
with methanol, and three new dimeric iridoid glucosides
(10, 12, 14) together with five iridoid glucosides (5–9).
Compound 1 was obtained as a brown powder,
[a]2D0—8.6ꢀ (c 1.16, CH3OH), with a quasi-molecular ion
at m/z 501.1042 generated by HR-FABMS, indicating
that the molecular formula of 1 was putatively
C19H26O12S. Its IR spectrum showed the presence of a
hydroxyl (3334 cmꢁ1), a g-lactone (1768 cmꢁ1) and an
* Corresponding author. Tel.: +81-88-622-9611; fax: +81-88-655-
3051.
E-mail address: asakawa@ph.bunri-u.ac.jp (Y. Asakawa).
0031-9422/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S0031-9422(02)00096-1

506
N. Quang et al. / Phytochemistry 60 (2002) 505–514
correlations with sulfur methyl group and H-10 indi-
cating the presence of the partial structure, CH3–S–
COO–CH2–. The position of the methoxyl group was
determined to be at C-3 by the presence of cross-peak
between methoxyl group and C-3 in HMBC correlation
of 1.
Furthermore, the glycosidic linkage of glucopyranosyl
moiety to C-1 position of aglycone was clearly indicated
by the cross-peak between an anomeric carbon signal [ꢀ
99.6, (C-10)] of glucopyranose and H-1 [ꢀ 5.10, (d, J=6.0
Hz)] of the aglycone in HMBC correlation (Table 1).
The sugar moiety was confirmed to be b-glucose by
1
comparing the H NMR and 13C NMR with those of
previous papers (Lavaud et al., 2001; Muhammad et al.,
2001).
The stereochemical assignment at C-4, C-5, C-6, C-9
of aglycone was based on 2D NMR NOESY experi-
ment of 1 (Table 1), which showed the NOEs between
(1) H-4; H-5 and 3-OCH3, (2) H-5; H-4; H-6 and H-9,
(3) H-6; H-5 and H-7, (4) H-9; H-5 and H-10, indicated
that they were cis (b-face) to each other. In addition, the
NOE correlation observed between H-1 and H-3, indi-
cated that they are cis (a-face). These assignments were
in agreement with those of 6b-O-substituted iridoid
glucosides (Damtoft et al., 1981).
Acetylation of 1 with Ac2O in pyridine yielded a tet-
raacetate (2), C27H34O16S, the IR spectrum of which
was similar to that of compound 1, except for the dis-
appearance of an absorption band corresponding to the
hydroxyl group at 3334 cmꢁ1 in place of the presence of
a signal at 1725 cmꢁ1 assignable to acetyl groups. The
1H and 13C NMR spectra of compound 2 were also
similar to those of compound 1, except for additional
signals at ꢀ 2.03, 2.03, 2.03 and 2.08 (4 CH3) for four
acetyl groups. Based on the above spectral and chemical
evidence, compound 1 was determined as 3,4-dihydro-3-
methoxypaederoside.
Bojthe-Horvath et al. (1982) reported the isolation of
3,4-dihydro-3-methoxyasperuloside without determina-
tion of stereochemistry of C-3 and they concluded that
the formation of this compound during plant extraction
can not be excluded although methanolysis of 6 is rather
slow. We suggested that 1 might be a naturally occurring
iridoid glucoside since the C-3 epimeric compound was
detected in neither HPLC nor 13C NMR experiments.
Compound 3 was obtained as a white powder, whose
molecular formula (C19H26O12SNa) was confirmed by
HR-FABMS [m/z 501.1071, expected m/z 501.1043)].
The IR and UV spectra showed absorption bands at
3374 cmꢁ1 (OH), 1700 cmꢁ1(C¼O), 1633 cmꢁ1(C¼C)
and absorption maxima at 234 nm (log E 4.16), respec-
tively. Acetylation of 3 with Ac2O in pyridine afforded a
pentaacetate (4) [HR-FABMS: m/z 688.1687 (C29H36
O17S, expected m/z 688.1673)]; ꢀH 1.94, 2.02, 2.04, 2.06,
2.07 indicating the presence of five hydroxyl groups in 3.
The 1H NMR spectrum of 3 showed the presence of two
ester (1714 cmꢁ1) group. The H NMR spectrum of 1
(Table 1) showed an olefinic proton at ꢀ 5.98 (br, s), one
methoxyl group at ꢀ 3.51 (s) and one sulfur methyl
group at ꢀ 2.35 (s), together with seven protons arising
from sugar moiety. The 13C NMR spectrum of 1 exhib-
ited 19 carbon signals due to 10 carbons of the main
iridoid skeleton (Damtoft et al., 1981) and six sugar
carbons, including one ester carbonyl (ꢀ 173.0) one
methyl sulfur (ꢀ 13.6) and one methoxy carbon (ꢀ 56.5),
as summarized in Table 1. The presence and position of
sulfur atom were determined by HR-FABMS and com-
parison of the NMR data with those of paederoside (5)
and asperuloside (7) (Suzuki et al., 1993) and the pre-
sence of higher frequency of n 1717 cmꢁ1, correspond-
ing to methyl thiocarbonate group (Suzuki et al., 1993).
From HMBC data of 1, a proton at ꢀ 3.25 showed
correlation with C-3 and C-5, therefore, it was assigned
to C-4. Other protons (ꢀ 5.10, 5.01, 3.40, 5.37, 5.98 and
3.02) were assigned to positions C-1, 3, 5, 6, 7, and 9,
respectively. The ester carbonyl (C-12) had HMBC
1

N. Quang et al. / Phytochemistry 60 (2002) 505–514
507
olefinic protons [ꢀ 7.65, (d, J=1.1, H-3), and ꢀ 6.02, (d,
J=1.7, H-7)], and one methoxy [ꢀ 3.74, (s, 11-OCH3)]
(Table 2). The UV, IR and NMR spectral data of 3
were similar to those of 6–7, indicating that 3 was the
same iridoid glucoside as 6–7 with the same absolute
configuration. Further identification of the structure of
3 was carried out by HMBC and NOESY experiments.
The cross peak between 11-OCH3 and C-11 was clearly
detected in HMBC spectrum indicating the presence of
a carbomethoxyl group.
NOEs were observed between each H-5, H-6 and H-9
indicating that they were cis (b-face). Thus, the structure
of compound 3 was established to be paederosidic acid
methyl ester.
It has been demonstrated that methanolysis of pae-
deroside (5) occurred when the methanolic solution of 5
Table 1
1H and 13C NMR assignments, HMBC and NOESY correlations of 1
Position
1H(ꢀ)
13C(ꢀ)
HMBC
NOESY
1
5.10 (d, 6.0)
5.01 (d, 3.6)
96.7
98.5
44.4
37.6
87.7
126.8
151.6
46.3
65.2
H-3, H-9, H-10
H-1, H-4, 3-OCH3
H-5, H-9
H-3, H-10
3
H-1, H-4, 3-OCH3
H-5, 3-OCH3
H-4, H-6, H-9
H-4, H-5, H-7
H-6, H-10
4
3.25 (dd, 3.6, 10.4)
3.40 (ddd, 6.6, 9.1, 10.4)
5.37 (br d, 6.6)
5.98 (br s)
5
H-4, H-6, H-9
H-7, H-9
6
7
H-5, H-9, H-10
H-7, H-9, H-10
H-1, H-5, H-10
H-7, H-9
8
9
10
3.02 (ddd, 0.8, 6.0, 9.1)
4.89 (br d, 15.7)
5.08 (br d, 15.7)
H-5, H-10
H-1, H-7, H-9
11
12
177.0
173.0
13.6
56.5
99.6
74.9
78.0
71.5
78.2
62.8
H-3, H-4, H-5
H-10, H-13
13
2.35 (s)
3.51 (s)
4.69 (d, 8.0)
3-OCH3
H-3
H-3, H-4
H-1, H-30, H-50
H-40
H-10, H-50
H-20, H-60
H-10, H-30, H-60
H-40, H-50
10
20
30
40
50
60
H-1, H-20
H-10, H-30
H-20, H-40
H-30, H-50, H-60
H-40, H-60
H-40, H-50
3.21 (dd, 8.0, 9.3)
3.38 (dd, 9.3, 9.1)
3.27 (dd, 9.1, 9.1)
3.31 (m)
3.68 (ddd, 1.6, 4.1, 11.8)
3.88 (dd, 1.4, 11.8)
Table 2
1H and 13C NMR assignments, HMBC and NOESY correlations of 3
Position
1H(ꢀ)
1H(ꢀ)a
13C(ꢀ)
HMBC
NOESY
1
5.06 (d, 8.5)
7.65 (d, 1.1)
101.3
155.4
H-3, H-9, H-10
H-5
H-3, H-9, H-10
H-1
3
7.71
108.1
3.11
4
H-3, H-5
42.4
75.3
5
3.03 (ddd, 1.1, 6.0,7.4)
4.80 (ddd, 0.8, 2.5, 6.0)
6.02 (d, 1.7)
H-3, H-7, H-9
H-5, H-7
H-9, H-10
H-6, H-9
H-5, H-7
H-6, H-9, H-10
6
7
6.13
145.5
2.71
5.06
132.4
8
H-7, H-9, H-10
46.2
66.2
9
10
2.62 (dd, 7.4, 8.5)
4.95 (br d, 14.6)
5.10 (dd, 1.3, 14.6)
H-1, H-5, H-10
H-1, H-7, H-9
H-1, H-5, H-10
H-7, H-9
11
12
172.9
169.3
2.38
11-OCH3
H-10, H-13
13.5
13
2.34 (s)
3.74 (s)
4.72 (d, 8.0)
11-OCH3
3.78
51.9
H-3
10
20
30
40
50
60
100.7
74.9
77.9
H-20
H-30, H-50
H-40
H-10, H-50
H-20, H-60
H-10, H-30, H-60
H-40, H-50
3.24 (dd, 8.0, 9.1)
3.38 (dd, 8.8, 9.1)
3.26 (dd, 8.8, 9.3)
3.27 (m)
H-10, H-30
H-20, H-40
H-30, H-50
H-40, H-60
H-50
71.6
78.6
3.63 (dd, 1.9, 11.8)
3.85 (dd, 6.0, 11.8)
3.46
63.0
a
Measured in D2O (Inouye et al., 1969c).

508
N. Quang et al. / Phytochemistry 60 (2002) 505–514
was refluxed for 100 h on a water bath to give several
decompositon products of which paederosidic acid
methyl ester (3) was obtained and its structure suggested
by IR, UV and H NMR spectroscopy (Inouye et al.,
1969c). Indeed, the IR, UV and 1H NMR data as
well as specific rotation of 3 obtained by methanolysis
spectra showed maxima absorption at 236 nm based on
unsaturated ester and the presence of a hydroxyl (3394
cmꢁ1), an ester (1702 cmꢁ1) and an olefinic (1633 cmꢁ1
group.
)
1
The 1H and 13C NMR data of 10 showed the presence
of two paederosidic acid moieties, one of which (the ‘b’
unit) was esterified with methanol, the other (‘a’ unit)
esterified with the 6b0-oxygen. This was proved partly
by the down field position of C-6b0 (d 63.8) and H-6b0 (d
4.30 and 4.46); the up field position of C-5b0 (d 75.7),
partly by correlation between H-6b0 and C-11a in
HMBC spectrum.
The configuration of carbon centers C-1a, C-5a, C-6a,
C-9a and C-1b, C-5b, C-6b, C-9b was determined by
NOE correlation as shown in the depicted structures
and in Table 3. The NOEs between (1) H-5a; H-6a and
resembled those of
P. scandens.
3 isolated from the present
Although the present crude extract was not refluxed
in methanol, it cannot be excluded that the methyl ester
(3) is formed during fractionation of the crude extract.
However, the C-6 epimeric compound of 5 has not been
isolated from or detected in the crude extract.
Dimer 10, [a]2D0 ꢁ5.7 (c 1.00, CH3OH), was obtained
as a yellowpowder. The FAB-MS had a quasi-mole-
cular ion peak at m/z 948 [M+Na]+. Its UV and IR
Table 3
1H and 13C NMR assignments, HMBC and NOESY correlations of compound 10
Position
1H(ꢀ)
13C(ꢀ)
HMBC
NOESY
1a
3a
4a
5a
6a
7a
8a
9a
10a
5.06 (d, 9.1)
7.69 (d, 1.4)
101.5
155.8
108.0
42.4
H-3a, H-9a, H-1a0
H-1a, H-5a
H-3a, H-5a
H-3a, H-1a0
H-1a
3.07 (ddd, 1.4, 6.0, 7.4)
4.81 (dd, 1.9, 6.0)
6.06 (d, 1.9)
H-3a, H-7a, H-9a
H-5a, H-7a
H-9a, H-10a
H-6a, H-9a
H-5a
H-10a
75.5
133.2
145.3
42.4
H-7a, H-9a, H-10a
H-1a, H-5a, H-10a
H-7a, H-9a
2.64 (dd, 7.4, 9.1)
4.99 (br d, 14.8)
5.09 (dd, 1.4, 14.8)
H-5a, H-10a
H-7a, H-9a
66.3
11a
12a
13a
1a0
2a0
3a0
4a0
5a0
6a0
168.6
172.7
13.6
100.7
74.9
77.9
71.6
78.6
63.0
H-3a, H-5a, H-6b0
H-10a, H-13a
2.35 (s)
4.73 (d, 8.0)
H-1a, H-2a0
H-1a0, H-3a0
H-2a0, H-4a0
H-3a0, H-5a0
H-4a0, H-6a0
H-4a0, H-5a0
H-1a, H-3a0, H-5a0
H-4a0
H-1a0, H-5a0
H-2a0, H-6a0
H-1a0, H-3a0, H-6a0
H-4a0, H-5a0
3.26 (dd, 8.0, 9.3)
3.84 (dd, 8.8, 9.3)
2.26 (t, 9.3)
3.28 (m)
3.64 (dd, 6.0, 12.1)
3.86 (dd, 1.9, 12.1)
5.00 (d, 8.5)
1b
3b
4b
5b
6b
7b
8b
9b
10b
102.1
155.4
107.9
42.3
H-3b, H-9b, H-1b0
H-1b, H-5b
H-3b, H-5b
H-3b, H-1b0
H-1b, 11b-OCH3
7.65 (d, 1.1)
3.02 (ddd, 1.1, 6.0, 7.4)
4.79 (dd, 1.7, 6.0)
6.02 (d, 1.7)
H-3b, H-7b, H-9b
H-5b, H-7b
H-9b, H-10b
H-6b, H-9b
H-5b
H-10b
75.1
132.7
145.3
42.3
H-7b, H-9b, H-10b
H-1b, H-5b, H-10b
H-7b, H-9b
2.62 (dd, 7.4, 8.5)
4.96 (dd, 1.7, 14.6)
5.03 (br d, 14.6)
H-5b, H-10b
H-7b, H-9b
66.3
11b
12b
13b
11b-OCH3
1b0
169.3
172.9
13.7
51.9
101.4
74.9
77.6
71.3
75.7
63.8
H-3b, H-5b, 11b-OCH3
H-10b, H-13b
2.34 (s)
3.74 (s)
4.72 (d, 8.0)
H-3b
H-1b, H-3b0, H-5b0
H-4b0
H-1b0, H-5b0
H-2b0, H-6b0
H-1b0, H-3b0, H-6b0
H-4b0, H-5b0
H-1b, H-2b0
H-1b0, H-3b0
H-2b0, H-4b0
H-3b0, H-5b0
H-4b0, H-6b0
H-4b0, H-5b0
2b0
3.27 (dd, 8.0, 9.6)
3.40 (dd, 8.8, 9.6)
3.93 (dd, 8.8, 9.3)
3.51 (m)
3b0
4b0
5b0
6b0
4.30 (dd, 4.8, 11.8)
4.46 (dd, 1.9, 11.8)

N. Quang et al. / Phytochemistry 60 (2002) 505–514
509
H-9a, (2) H-5b; H-6b and H-9b indicated that they were
cis (or b-face). On the other hand, the presence of NOEs
between (1) H-1a and H-3a and (2) H-1b and H-3b and
the absence of NOEs between (1) H-1a and H-9a and
(2) H-1b and H-9b suggested that the configuration of
H-1a and H-1b were a-face.
Acetylation of 10 with acetic anhydride in pyridine
afforded compound 11 as oil, [a]2D0 +51.6 (c 0.30,
CHCl3), the IR spectrum of which was similar to those
of 10 except for the disappearance of the absorption
band of a hydroxyl group at 3394 cmꢁ1 in place of the
absorption bands at 1725 and 1223 cmꢁ1 assignable to
1
an acetyl group. The H and 13C NMR spectra of 11
were also similar to those of 10, except for nine singlet
signals (ꢀ 1.92, 1.96, 2.02, 2.02, 2.03, 2.04, 2.06, 2.07,
2.07) due to nine acetyl groups. The HR-FABMS of 11
at m/z 1325.2900 corresponding to the molecular
formula C55H66O32S2Na supported the original dimeric
structure of 10.
Fig. 1. Important HMBC and NOESY correlations of 10.
Table 4
1H and 13C NMR assignments, HMBC and NOESY correlations of compound 12
Position
1H(ꢀ)
13C(ꢀ)
HMBC
NOESY
1a
3a
4a
5a
6a
7a
8a
9a
10a
5.06 (d, 8.2)
7.71 (d, 1.1)
101.6
156.2
107.7
42.8
H-3a, H-9a, H-1a0
H-1a, H-5a
H-3a, H-5a
H-6a, H-9a
H-5a, H-7a
H-9a, H-10a
H-7a, H-9a, H-10a
H-1a, H-7a, H-10a
H-7a, H-9a
H-3a, H-1a0
H-1a
2.89 (ddd, 1.1, 6.1, 8.2)
4.79 (d, 6.1)
6.00 (d, 2.2)
H-6a, H-9a
H-5a, H-7a
H-6a, H-10a
72.5
131.7
146.0
46.0
2.72 (dd, 8.2, 8.2)
4.91 (br d, 14.8)
5.14 (dd, 1.4, 14.8)
H-5a, H-10a
H-7a, H-9a
66.3
11a
12a
13a
1a0
2a0
3a0
4a0
5a0
6a0
167.5
172.9
13.6
100.9
74.9
77.8
71.6
78.6
63.0
H-3a, H-2b0
H-10a, H-13a
2.34 (s)
4.71 (d, 8.0)
3.27 (dd, 8.0, 9.1)
3.39 (t, 9.1)
3.29 (t, 8.8)
3.32(m)
3.64 (dd, 6.0, 12.0)
3.85 (br d, 12.0)
5.85 (d, 1.4)
7.16 (d, 1.9)
H-1a, H-2a0
H-1a0, H-3a0
H-2a0, H-4a0
H-3a0, H-5a0
H-4a0, H-6a0
H-4a0, H-5a0
H-1a, H-3a0, H-5a0
H-4a0
H-1a0, H-5a0
H-2a0, H-6a0
H-1a0, H-3a0, H-6a0
H-4a0, H-5a0
1b
3b
4b
5b
6b
7b
8b
9b
10b
94.0
H-3b, H-9b, H-1b0
H-1b, H-5b
H-3b, H-5b
H-6b, H-9b
H-5b, H-7b
H-9b, H-10b
H-7b, H-9b, H-10b
H-1b, H-7b, H-10b
H-7b, H-9b
H-3b, H-1b0
H-1b
150.1
106.2
37.6
3.47 (ddd, 1.9, 6.6, 8.8)
5.52 (br d, 6.6)
5.71 (br s)
H-6b, H-9b
H-5b, H-7b
H-6b, H-10b
86.0
129.8
143.6
45.0
3.28 (dd, 1.4, 8.8)
4.80 (br d, 14.0)
4.89 (dd, 1.4, 14.0)
H-5b, H-10b
H-7b, H-9b
64.3
11b
12b
13b
1b0
2b0
3b0
4b0
5b0
6b0
172.6
172.1
13.6
98.6
74.4
75.5
71.5
78.5
62.6
H-3b
H-10b, H-13b
2.35 (s)
4.93 (d, 8.0)
4.79 (dd, 8.0, 9.6)
3.68 (dd, 8.8, 9.6)
3.38 (t, 8.8)
4.43 (m)
3.68 (dd, 1.4, 11.8)
3.94 (dd, 1.9, 11.8)
H-1b, H-2b0
H-1b0, H-3b0
H-2b0, H-4b0
H-3b0, H-5b0
H-4b0, H-6b0
H-4b0, H-5b0
H-1b, H-3b0, H-5b0
H-4b0
H-1b0, H-5b0
H-2b0, H-6b0
H-1b0, H-3b0, H-6b0
H-4b0, H-5b0

510
N. Quang et al. / Phytochemistry 60 (2002) 505–514
On the basis of the above spectroscopic and chemical
data, the structure of 10 was determined to be the dimer
depicted in Fig. 1.
Dimer 12 was obtained as a yellow powder, [a]D20
ꢁ108.9ꢀ (c 0.54, CH3OH). The FAB-MS of 12 gave a
quasi-molecular ion peak at m/z 915 [M+Na]+. Its UV
and IR spectra showed absorption maximum at 239 nm
and the presence of a hydroxyl (3318 cmꢁ1), an unsatu-
rated g-lactone (1746 cmꢁ1) and an a, b-unsaturated
ester (1706 cmꢁ1) groups, respectively. The 1H and
13C NMR spectra of 12 (Table 4) resembled those of 10,
except the signal of H-6b was shifted to lower field at
ꢀH5.52 (br d, J=6.6) and chemical shifts of C-6b and
C-11b appeared at higher frequency at ꢀC 86.0 ppm and
172.6 ppm, respectively, indicating the presence of a
five-membered lactone ring. The two partial structures
of 12 were determined to be paederoside (5) and pae-
derosidic acid (7) by comparing their spectral data with
those of paederoside and paederosidic acid isolated
from the same plant. Acetylation of 12 with acetic
anhydride in pyridine afforded compound 13, [a]D20
ꢁ35.0ꢀ (c 0.40, CHCl3). HR-FABMS of 13 at m/z
1251.2490 suggested a molecular formula of C52H60
O30S2Na. The IR spectrum of 13 was similar to those of
12 except for the disappearance of the absorption band
3318 cmꢁ1 due to a hydroxl group at in place of
absorption bands at 1725 and 1226 cmꢁ1 due to an ace-
tyl group. The 1H and 13C NMR spectra of 13 were also
similar to those of 12, except for eight singlet signals (ꢀ
1.91, 1.99, 2.02, 2.04, 2.05, 2.06, 2.10, 2.12) due to eight
acetyl groups, indicating the presence of eight hydroxyl
groups in 12. In addition, the ester linkage between
C-11a of paederosidic acid and C-2b0 of sugar moiety of
paederoside was established by the correlation between
H-2b0 and C-11a in HMBC spectrum (Table 4). The
molecular ion peak at m/z 1251.2490 of 13 in HR-FABMS
confirmed the proposed dimeric structure (Fig. 2).
Fig. 2. Important HMBC and NOESY correlations of 12.
Compound 14 was not obtained as pure state, thus it
was acetylated after the absence of acetyl group was
confirmed by NMR spectra, followed by purification of
the reaction mixture using HPLC to afford 15, HR-
FABMS of which showed the molecular peak at m/z
1311.2730, suggesting the molecular formula C54H64O32
Fig. 3. Important HMBC and NOESY correlations of 14.
1
S2Na. The H and 13C NMR spectra of 15 (Table 5)
(Otsuka et al., 1991; Suzuki et al., 1993; Calis et al.,
2001), paederosidic acid, (Inouye et al., 1969a–c; Calis et
al., 2001), asperulosidic acid (Otsuka et al., 1991; Calis
et al., 2001) and geniposide (Inouye et al., 1969a–c;
Jensen et al., 1973; Cameron et al., 1984; Inouye et al.,
1988; Morota et al., 1989) by spectral data, respectively.
This is the first report of the isolation of a newiridoid
glucoside (1) and three dimeric sulfur-containing iridoid
glucosides (10, 12 and 14). In addition, it is the first time
that geniposide (9) has been isolated from P. scandens
although plants belonging to Rubiaceae family are well
known to contain various iridoid glucosides (Inouye et
al., 1988).
closely resembled those of 11; they differed in the fol-
lowing points. It had no signal for methoxyl group and a
cross-peak appeared between C-11a and H-3b0 in HMBC,
indicating the presence of an ester linkage between C-11a
of carboxyl group and C-3b0 of sugar moiety (Table 5).
Based on the spectral data of dimer 15 relative to those of
11, dimer 14 appeared to contain two monomers of pae-
derosidic acid (Fig. 3). HR-FABMS (m/z 1311.2730)
supported the proposed structure for 15.
Compounds 5, 6, 7, 8 and 9 were identified as pae-
deroside (Inouye et al., 1969a–c; Kapadia et al., 1979;
Suzuki et al., 1993; Calis et al., 2001), asperuloside

N. Quang et al. / Phytochemistry 60 (2002) 505–514
511
Table 5
1H and 13C NMR assignments, HMBC and NOESY correlations of compound 15
Position
1H(ꢀ)
13C(ꢀ)
HMBC
NOESY
1a
3a
4a
5a
6a
7a
8a
9a
10a
4.82 (d, 8.0)
7.53 (d, 1.4)
100.3
154.6
105.2
38.9
H-3a, H-9a, H-1a0
H-1a, H-5a
H-3a, H-5a
H-3a, H-1a0
H-1a
3.18 (ddd, 1.4, 6.1, 8.0)
5.64 (dd, 2.2, 6.1)
6.12 (d, 2.2)
H-3a, H-6a, H-9a
H-5a, H-7a, H-9a
H-6a, H-9a, H-10a
H-7a, H-9a, H-10a
H-5a, H-7a
H-6a, H-9a
H-5a, H-7a
H-6a, H-10a
76.8
128.6
146.6
44.7
2.57 (t, 8.0)
4.92 (dd, 2.2, 15.4)
5.10 (brd, 15.4)
H-5a, H-10a
H-7a, H-9a
64.4
H-7a, H-9a
11a
12a
13a
1a0
2a0
3a0
4a0
5a0
6a0
165.3
171.1
13.5
97.8
70.8
72.6
68.0
72.0
61.5
H-3a, H-3b0
H-10a, H-13a
2.36 (s)
4.94 (d, 8.0)
H-1a, H-2a0
H-1a0, H-3a0
H-2a0, H-4a0
H-3a0, H-5a0
H-4a0
H-1a, H-3a0, H-5a0
H-4a0
H-1a0, H-5a0
H-2a0, H-6a0
H-1a0, H-3a0, H-6a0
H-4a0, H-5a0
5.06 (dd, 8.0, 9.6)
5.25 (t, 9.6)
5.14 (dd, 9.3, 9.6)
3.73 (m)
4.16 (dd, 2.2, 12.4)
4.21 (dd, 4.4, 12.4)
4.83 (d, 8.2)
H-5a0
1b
3b
4b
5b
6b
7b
8b
9b
10b
100.4
154.6
105.2
38.6
H-3b, H-9b, H-1b0
H-1b, H-5b
H-3b, H-5b
H-3b, H-1b0
H-1b
7.65 (d, 1.1)
3.25 (ddd, 1.1, 6.1, 8.2)
5.75 (br d, 6.1)
6.13 (d, 1.9)
H-3b, H-6b, H-9b
H-5b, H-7b, H-9b
H-6b, H-9b, H-10b
H-7b, H-9b, H-10b
H-5b, H-7b
H-6b, H-9b
H-5b, H-7b
H-6b, H-10b
76.8
128.6
146.6
45.1
2.64 (t, 8.2)
4.92 (dd, 2.2, 15.4)
5.10 (brd, 15.4)
H-5b, H-10b
H-7b, H-9b
64.4
H-7b, H-9b
11b
12b
13b
1b0
2b0
3b0
4b0
5b0
6b0
170.5
171.1
13.5
97.7
71.1
72.4
68.2
72.1
61.5
H-3b
H-10b, H-13b
2.35 (s)
4.98 (d, 8.0)
H-1b, H-2b0
H-1b0, H-3b0
H-2b0, H-4b0
H-3b0, H-5b0
H-4b0
H-1b, H-3b0, H-5b0
H-4b0
H-1b0, H-5b0
H-2b0, H-6b0
H-1b0, H-3b0, H-6b0
H-4b0, H-5b0
5.06 (dd, 8.0, 9.6)
5.29 (dd, 9.3, 9.6)
5.18 (t, 9.6)
3.77 (m)
4.16 (dd, 2.5, 12.4)
4.23 (dd, 4.4, 12.4)
1.95 (s), 1.96 (s), 2.01 (s)
2.02 (s), 2.03 (s), 2.04 (s)
2.07 (s), 2.07 (s), 2.08 (s)
H-5b0
CH3CO
CH3CO
20.6, 20.6, 20.6
20.6, 20.7, 20.7
20.7, 21.1, 21.1
H-6b, H-6a, H-2b0
H-2a0, H-3a0, H-4b0
H-4a0, H-6b0, H-6a0
169.3, 169.4, 169.4
169.5, 169.8, 170.2
170.2, 170.5, 170.5
3. Experimental
JOEL JMS AX-500 spectrometer. IR spectra were mea-
sured on JASCO FT/IR-5300 spectrophotometer. The
UV spectra were obtained on a Hitachi U-3000 spectro-
photometer or Shimadzu UV-1650PC in MeOH solution.
The specific optical rotations were measured on a JASCO
DIP-1000 polarimeter with CHCl3 or MeOH as solvents.
HPLC was performed on Shimadzu liquid chromato-
graphy LC-10AS with RID-6A and SPD-10A detectors
using a Waters 5C 18-AR-II or 5 SL-II column. TLC was
performed on silica gel plates (Kiesegel 60 F254, Merck)
and reversed phase C 18 silica gel plates (Merck), using
3.1. General
NMR spectra were recorded on Varian Unity 600
(600 MHz), using either CDCl3 or CD3OD as solvent.
Chemical shifts were given in a value with TMS being
used as internal standard (1H NMR), and ꢀ 77.03 (ppm)
from CDCl3 and ꢀ 49.00 (ppm) from CD3OD as a stan-
dard (13C NMR). Mass spectra including high-resolution
and high-resolution FAB mass spectra were recorded on a

512
N. Quang et al. / Phytochemistry 60 (2002) 505–514
solvent system A: CHCl3–MeOH–H2O (65:35:10, lower
phase) and solvent system B: MeOH–H2O (60: 40). The
spots of TLC were detected under UV 254 nm and by
spraying with 10% H2SO4 or Godin reagent (Godin,
+16.8ꢀ (c 1.20 MeOH)]; Positive FAB-MS: 501
[M+Na]+. HR-MS: m/z 501.1071 (C19H26O12SNa,
expected m/z 501.1043). UV lmax (CH3OH) nm (logE):
234 (4.16), lit. (Inouye et al., 1969c) 236 (4.02); IR
(KBr): 3374, 2929, 1700, 1633, 1440, 1308, 1159, 1077,
898 cmꢁ1, lit. (Inouye et al., 1969c) 1700, 1635 cmꢁ1; 1H
and 13C NMR (CD3OD) (see Table 2).
ꢀ
1954), followed by heating at 120 C.
3.2. Materials
Fresh roots of Paederia scandens (Lour) Merrill were
collected in Hanoi, Vietnam in July 2000 and then iden-
tified by Dr. Tran Ngoc Ninh (Ecological and Biological
Resource Center, Hanoi, Vietnam). The voucher speci-
men (VN 02001) has been deposited in the Faculty of
Pharmaceutical Sciences, Tokushima Bunri University.
3.3.3. Dimer 10
Yellowpowder, [ a]D20 ꢁ5.7ꢀ (c 1.00, CH3OH). Positive
FAB-MS: 948 [M+Na]+. UV lmax (CH3OH) nm
(logE): 236 (3.92). IR (Neat): 3394, 2920, 1702, 1633,
1440, 1379, 1294, 1161, 1102, 950 cmꢁ1. 1H and 13C NMR
(CD3OD) (see Table 3).
3.3. Extraction and isolation
3.3.4. Dimer 12
Yellowpowder, [ a]D20 ꢁ108.9ꢀ (c 0.54, CH3OH). Posi-
tive FAB-MS: 915 [M+Na]+. UV lmax (CH3OH) nm
(logE): 239 (4.05). IR (Neat): 3418, 2925, 1746, 1706,
Roots of Vietnamese P. scandens (3.2 kg) were dried
at room temperature and powdered, then extracted with
MeOH using Soxhlet apparatus. The MeOH extract
was concentrated in vacuo to give a residue (118.6 g)
which was extracted again with butanol to give 57.2 g
butanol extract. Silica gel column chromatography of
butanol extract (19.79 g), using CHCl3–MeOH–H2O
(65:15:10, lower phase) as eluent, partly resulted in the
isolation of six fractions (Fraction 1–6). Fraction 1 and
2 contained compound 1 (190.7 mg) and compound 3
(382.5 mg), respectively as pure state. Fractions 3
(1477.4 mg) and 4 (389.8 mg) was subjected to reversed
phase column HPLC (Shimadzu liquid chromatography
LC-10AS with RID-6A and SPD-10A detectors using a
Waters 5C 18-AR-II) with MeOH–H2O (40:60) as sol-
vent (flowrate 0.5–0.7 ml/min). Paederoside ( 5) (876.5
mg) was obtained from fraction 3, whereas asperuloside
(6) (5.83 mg) and geniposide (9) (35.3 mg) were obtained
from fraction 4. Fractions 5 (663 mg) and 6 (683 mg)
were purified by HPLC with reversed phase column
1657, 1272, 1166, 1084, 901 cmꢁ1. H and 13C NMR
1
(CD3OD) (see Table 4).
3.3.5. Acetylation of 1
Compound 1 (30 mg) in pyridine (2 ml) was acetyl-
ated with acetic anhydride (2 ml) and worked up as
usual afforded tetraacetate (2)(35.1 mg) as oil, [a]D20
ꢁ11.6ꢀ (c 1.18, CHCl3). HR-MS: m/z 646.1526 (C27H34
O16S, requires m/z 646.1568). IR (KBr): 2939, 1755,
1725, 1435, 1368, 1227, 1145, 1037 cmꢁ1 1H-NMR
.
(CDCl3): ꢀ 6.01 (1H, br s, H-7), 5.34 (1H, br d, J=6.9
Hz, H-6), 5.22 (1H, dd, J=9.3, 9.6 Hz, H-30), 5.12 (1H,
t, J=9.3 Hz, H-40), 5.05 (1H, d, J=6.0 Hz, H-1), 5.02
(1H, dd, J=8.2, 9.6 Hz, H-20), 5.01 (1H, d, J=3.9 Hz,
H-3), 4.97 (1H, br d, J=15.5 Hz, H-10), 4.92 (1H, d,
J=8.2 Hz, H-10), 4.83 (1H, br d, J=15.5 Hz, H-10),
4.23 (1H, dd, J=4.7, 12.4 Hz, H-60), 4.13 (1H, dd,
J=2.5, 12.4 Hz, H-60), 3.72 (1H, m, H-50), 3.45 (3H, s,
3-OCH3), 3.32 (1H, ddd, J=6.9, 9.1, 10.4 Hz, H-5), 3.02
(1H, dd, J=3.9, 10.4 Hz, H-4), 3.01 (1H, dd, J=6.0, 9.1
Hz, H-9), 2.35 (3H, s, H-13), 2.08 (3H, s, CH3CO), 2,03
(9H, s, 3ꢂCH3CO); 13C NMR (CDCl3): ꢀ 174.4 (C-11),
172.6 (CH3CO), 171.1 (C-12), 170.2 (CH3CO), 169.4
(CH3CO), 169.3 (CH3CO), 149.2 (C-8), 126.3 (C-7),
96.8 (C-3), 96.0 (C-10), 95.3 (C-1), 85.7 (C-6), 72.9 (C-
30), 71.9 (C-50), 71.0 (C-20), 68.2 (C-40), 63.5 (C-10), 61.7
(C-60), 55.6 (3-OCH3), 44.8 (C-9), 42.9 (C-4), 36.1 (C-5),
20.6 (3xCH3CO), 20.7 (CH3CO), 13.5 (C-13).
[flowrate 0.7 ml/min, solvent MeOH–H O (60: 40)] to
2
give paederosidic acid (7) (333.7 mg) and dimer (10)
(10.4 mg) from fraction 5 and asperulosidic acid (8)
(11.7 mg), dimer 12 (7.3 mg) and a mixture containing
14 (27.3 mg) from fraction 6. The latter mixture was
acetylated and purified by HPLC (C 18), using CH3CN
as solvent to obtain 15 (10.4 mg) as acetate of 14.
3.3.1. Glucoside 1
Brown powder, TLC solvent system A, Rf 0.60. [a]D20
ꢁ8.6ꢀ (c 1.16, MeOH). Positive FAB-MS: 501 [M+
Na]+. HR-MS: m/z 501.1042 (C19H26O12SNa, expected
m/z 501.1043). IR (KBr): 3334, 2935, 1768, 1714, 1148,
3.3.6. Acetylation of 3
Acetylation of 3 (30 mg) was carried out by the same
method as described above to give pentaacetate (4) (39.1
mg) as oil, [a]2D0+19.9ꢀ (c 2.34, CHCl3). HR-MS: m/z
688.1687 (C29H36O17S, requires m/z 688.1673). UV lmax
(CH3OH) nm (logE): 235 (4.37). IR (KBr): 2954, 1725,
1073, 944 cmꢁ1
Table 1).
.
1H and 13C NMR (CD3OD)(see
3.3.2. Glucoside 3 (=Paederosidic acid methyl ester)
White powder, TLC solvent system A, Rf 0.52. [a]D20
+12.4ꢀ [c 0.90, MeOH], lit. (Inouye et al., 1969c)
1637, 1436, 1370, 1227, 1148, 1042, 958 cmꢁ1. HNMR
(CDCl3): ꢀ 7.56 (1H, d, J=1.7 Hz, H-3), 6.09 (1H, br d,
1

N. Quang et al. / Phytochemistry 60 (2002) 505–514
513
J=1.9 Hz, H-7), 5.76 (1H, dd, J=1.9, 6.3 Hz, H-6), 5.25
(1H, t, J=9.6 Hz, H-30), 5.14 (1H, dd, J=9.6, 10.2 Hz,
H-40), 5.05 (1H, dd, J=8.2, 9.6 Hz, H-20), 5.01 (1H, dd,
J=1.7, 15.1 Hz, H-10), 4.94 (1H, d, J=8.2 Hz, H-10),
4.92 (1H, br d, J=15.1 Hz, H-10), 4.79 (1H, d, J=8.8
Hz, H-1), 4.22 (1H, dd, J=4.4, 12.4 Hz, H-60), 4.16 (1H,
dd, J=2.5, 12.4 Hz, H-60), 3.74 (1H, m, H-50), 3.73 (3H,
s, 3-OCH3), 3.25 (1H, ddd, J=1.7, 6.3, 8.0 Hz, H-5),
2.62 (1H, dd, J=8.2, 8.8 Hz, H-9), 2.36 (3H, s, H-13),
2.07 (3H, s, CH3CO), 2.06 (3H, s, CH3CO), 2.04 (3H, s,
CH3CO), 2.02 (3H, s, CH3CO), 1.94 (3H, s, CH3CO).
13C NMR (CDCl3): d 171.1 (C-12), 170.5 (CH3CO),
170.2 (CH3CO), 169.8 (CH3CO), 169.3 (CH3CO), 169.2
(CH3CO), 166.8 (C-11), 153.1 (C-3), 146.2 (C-8), 128.4
(C-7), 106.6 (C-4), 100.2 (C-1), 97.8 (C-10), 77.0 (C-6),
72.4 (C-30), 72.1 (C-50), 70.8 (C-20), 68.2 (C-40), 64.5 (C-
10), 61.6 (C-60), 51.5 (3-OCH3), 45.2 (C-9), 38.8 (C-5),
21.0 (CH3CO), 20.7 (CH3CO), 20.6 (3ꢂCH3CO), 13.5
(C-13).
77.0 (C-6a and C-6b), 72.5 (C-3a0), 72.4 (C-5a0 and C-
3b0), 72.1 (C-5b0), 70.8 (C-2a0 and C-2b0), 68.2 (C-4a0),
67.9 (C-4b0), 64.5 (C-10a and C-10b), 61.6 (C-6a0), 61.0
(C-6b0), 51.6 (11b-OCH3), 45.1 (C-9b), 45.0 (C-9a), 38.9
(C-5b), 38.8 (C-5a), 21.1 (CH3CO), 21.0 (CH3CO), 20.7
(3ꢂCH3CO), 20.6 (4ꢂCH3CO), 13.5 (C-13a and 13b).
3.3.8. Acetylation of 12
Acetylation of 12 (2.8 mg) in the same manner as
described above gave compound 13 (3.8 mg) as oil. [a]D20
ꢁ35.0ꢀ (c 0.40, CHCl3). Positive FAB-MS: 1251 [M+
Na]+. HR-FABMS: m/z 1251.2490 (C52H60O30 S2Na,
expected m/z 1251.2509). UV lmax (CH3OH) nm (logE):
234 (4.05). IR (KBr): 2935, 1755, 1725, 1661, 1634,
1435, 1370, 1226, 1145, 1041, 908 cmꢁ1 1HNMR
.
(CDCl3): ꢀ 7.48 (1H, d, J=1.4 Hz, H-3a), 7.12 (1H, d,
J=1.9 Hz, H-3b), 6.08 (1H, d, J=2.2 Hz, H-7a), 5.76
(1H, br s, H-7b), 5.68 (1H, d, J=1.4 Hz, H-1b), 5.67
(1H, dd, J=2.2, 6.0 Hz, H-6a), 5.47 (1H, br d, J=6.3
Hz, H-6b), 5.29 (1H, t, J=9.6 Hz, H-3a0), 5.25 (1H, t,
J=9.6 Hz, H-3b0), 5.14 (2H, t, J=9.6 Hz, H-4a0 and
H-4b0), 5.05 (2H, dd, J=8.0, 9.6 Hz, H-2a0 and H-2b0),
5.01 (1H, dd, J=1.9, 15.4 Hz, H-10a), 4.98 (1H, d, J=
8.0 Hz, H-1a0), 4.91 (1H, d, J=8.0 Hz, H-1b0), 4.90 (1H,
br d, J=15.4 Hz, H-10a), 4.82 (1H, d, J=8.8 Hz, H-1a),
4.81 (1H, dd, J=1.4, 13.7 Hz, H-10b), 4.76 (1H, dd,
J=1.1, 13.7 Hz, H-10b), 4.36 (2H, dd, J=4.7, 12.4 Hz,
H-6a0 and H-6b0), 4.20 (1H, dd, J=4.4, 12.4 Hz, H-6a0),
4.16 (1H, dd, J=2.5, 12.4 Hz, H-6b0), 3.80 (1H, m,
H-5b0), 3.74 (1H, m, H-5a0), 3.46 (1H, ddd, J=1.9, 6.3,
6.9 Hz, H-5b), 3.25 (1H, br d, J=6.9 Hz, H-9b), 3.09
(1H, ddd, J=1.4, 6.0, 8.0 Hz, H-5a), 2.67 (1H, dd,
J=8.0, 8.8 Hz, H-9a), 2.36 (3H, s, H-13a), 2.35 (3H, s,
H-13b), 2.12 (3H, s, CH3CO), 2.10 (3H, s, CH3CO),
2.06 (3H, s, CH3CO), 2.05 (3H, s, CH3CO), 2.04 (3H, s,
CH3CO), 2.02 (3H, s, CH3CO), 1.99 (3H, s, CH3CO),
1.91 (3H, s, CH3CO). 13CNMR (CDCl3): d 171.3
(C-12b), 171.0 (C-12a), 170.6 (2ꢂCH3CO), 170.2 (2ꢂ
CH3CO), 169.6 (CH3CO), 169.4 (CH3CO), 169.3 (2ꢂ
CH3CO), 168.9 (C-11b), 164.3 (C-11a), 154.1 (C-3a),
147.6 (C-3b), 146.7 (C-8a), 140.7 (C-8b), 129.8 (C-7b),
127.9 (C-7a), 105.6 (C-4a), 105.3 (C-4b), 99.8 (C-1a), 97.0
(C-1a0), 96.6 (C-1b0), 91.8 (C-1b), 83.8 (C-6b), 77.5 (C-6a),
72.5 (C-5a0), 72.3 (C-5b0), 72.2 (C-3b0), 72.1 (C-3a0), 70.7
(C-2b0), 70.2 (C-2a0), 68.2 (C-4a0), 68.1 (C-4b0), 64.5 (C-
10a), 62.9 (C-10b), 61.7 (C-6b0), 61.6 (C-6a0), 44.8 (C-9a),
43.5 (C-9b), 39.1 (C-5a), 36.0 (C-5b), 20.6 (8ꢂ CH3CO),
13.5 (C-13a and C-13b).
3.3.7. Acetylation of 10
Compound 10 (5.02 mg) in pyridine (1 ml) was
acetylated with acetic anhydride (1 ml) and worked up
as usual gave compound 11 (6.25 mg) as oil. [a]D20
+51.6ꢀ (c 0.30, CHCl3). Positive FAB-MS: 1325
[M+Na]+. HR-FABMS: m/z 1325.2900 (C55H66O32
S2Na, expected m/z 1325.2876). UV lmax (CH3OH) nm
(logE): 235 (4.47). IR (KBr): 2935, 1725, 1714, 1636,
1437, 1372, 1223, 1148, 1070, 958 cmꢁ1 1H NMR
.
(CDCl3) ꢀ 7.63 (1H, d, J=1.7 Hz, H-3a), 7.55 (1H, d,
J=1.7 Hz, H-3b), 6.07 (1H, d, J=1.9 Hz, H-7a), 6.05
(1H, d, J=1.9 Hz, H-7b), 5.76 (1H, dd, J=1.9, 6.0 Hz,
H-6b), 5.73 (1H, dd, J=1.9, 6.0 Hz, H-6a), 5.25 (2H, t,
J=9.6 Hz, H-3a0 and H-3b0), 5.14 (1H, dd, J=9.6, 9.9
Hz, H-4b0), 5.10 (1H, dd, J=9.6, 9.9 Hz, H-4a0), 5.06
(1H, dd, J=8.0, 9.6 Hz, H-2a0), 5.05 (1H, dd, J=8.0, 9.6
Hz, H-2b0), 5.00 (2H, br d, J=14.8 Hz, H-10a and H-
10b), 4.97 (1H, d, J=8.0 Hz, H-1b0), 4.96 (1H, d, J=8.0
Hz, H-1a0), 4.93 (2H, dd, J=2.2, 14.8 Hz, H-10a and H-
10b), 4.83 (1H, d, J=8.8 Hz, H-1b), 4.82 (1H, d, J=8.8
Hz, H-1a), 4.40 (1H, dd, J=2.2, 12.4 Hz, H-6b0), 4.22
(1H, dd, J=4.7, 12.4 Hz, H-6a0), 4.17 (1H, dd, J=4.1,
12.4 Hz, H-6b0), 4.16 (1H, dd, J=2.5, 12.4 Hz, H-6a0),
3.75 (1H, m, H-5a0), 3.73 (3H, s, 11b-OCH3), 3.71 (1H,
m, H-5b0), 3.25 (2H, ddd, J=1.7, 6.0, 7.7 Hz, H-5a and
H-5b), 2.63 (2H, dd, J=7.7, 8.8 Hz, H-9a and H-9b),
2.36 (6H, s, H-13a and H-13b), 2.07 (6H, s, 2ꢂCH3CO),
2.06 (3H, s, CH3CO), 2.04 (3H, s, CH3CO), 2.03 (3H, s,
CH3CO), 2.02 (6H, s, 2ꢂ CH3CO), 1.96 (3H, s, CH3CO),
1.92 (3H, s, CH3CO); 13C-NMR (CDCl3): ꢀ 171.1 (C-
12a and 12b), 170.5 (2ꢂ CH3CO), 170.2 (CH3CO),
170.1 (CH3CO), 169.8 (CH3CO), 169.7 (CH3CO), 169.3
(2ꢂCH3CO), 169.2 (CH3CO), 166.8 (C-11b), 165.7 (C-
11a), 154.0 (C-3a), 153.1 (C-3b), 146.3 (C-8a and C-8b),
128.5 (C-7a), 128.3 (C-7b), 106.5 (C-4b), 105.9 (C-4a),
100.7 (C-1b), 100.2 (C-1a), 98.5 (C-1b0), 97.6 (C-1a0),
3.3.9. Acetylation of a mixture containing 14
A mixture (27.3 mg) containing 14 was acetylated
with Ac2O in pyridine. Work up as usual gave com-
pound 15 (10.4 mg) as oil, [a]2D0+17.9ꢀ (c 0.35, CHCl3).
Positive FAB-MS: 1311 [M+Na]+. HR-FABMS: m/z
1311.2730 (C54H64O32S2Na, expected m/z 1311.2720).
UV lmax (CH3OH) nm (logE): 234 (4.36). IR (KBr):

514
N. Quang et al. / Phytochemistry 60 (2002) 505–514
2940, 1725, 1634, 1435, 1372, 1231, 1149, 1070, 956
1
Inouye, H., Takeda, Y., Nhishimura, H., Kanomi, A., Okuda, T.,
Puff, C., 1988. Chemotaxonomic studies of Rubiaceous plants con-
taining iridoid glucosides. Phytochemistry 27, 2591–2598.
Jensen, S.R., Kjaer, A., Nielsen, B.J., 1973. Geniposide and mono-
tropein in Cornus suecica. Phytochemistry 12, 2065–2066.
Kadota, S., 2000. Traditional medicine in Vietnam, Thailand and
Myanmar. Investigation on Natural Drug Resources, 16–68.
Kapadia, G.J., Sharma, S.C., Tokuda, H., Nishino, H., Ueda, S.,
1996. Inhibitory of iridoid glucosides on Epstein-Barr virus activa-
tion by short-term in vitro assay for anti-tumor promoters. Cancer
Letters 102, 223–226.
cmꢁ1. H and 13C NMR (CDCl3) (see Table 5).
Acknowledgements
The authors thank Miss. Y. Okatomo (TBU, Japan)
for the recording mass spectra. Thanks are due to Dr.
Tran Ngoc Ninh (Ecological and Biological Resource
Center, Hanoi, Vietnam) for identification of the plant.
Kapadia, G.J., Shukla, Y.N., Bose, A.K., Fujiwara, H., Lloyd, H.A.,
1979. Revised structure of paederoside,
a novel monoterpene
S-methyl thiocarbonate. Tetrahedron Letters 22, 1937–1938.
Lavaud, C., Crublet, M., Laure Pouny, I., Litaudon, M., Sevenet, T.,
2001. Triterpenoid saponins from the stem bark of Elattostachys
apetala. Phytochemistry 57, 469–478.
References
Bojthe-Horvath, K., Hetenyi, F., Kocsis, A., Szabo, K.L., Varga-
Balazs, M., Mathe Jr, I., Tetenyi, P., 1982. Iridoid glucosides from
Galium verum. Phytochemistry 21, 2917–2919.
Morota, T., Sasaki, H., Nishimura, H., Sugama, K., Chin, M., Mit-
suhashi, H., 1989. Two iridoid glucosides from Rehmannia glutinosa.
Phytochemistry 28, 2149–2153.
Calis, I., Heilmann, J., Tasdemir, D., Linden, A., Ireland, C.M., Sti-
cher, O., 2001. Flavonoid, iridoid, and lignan glycosides from
Putoria calabrica. Journal of Natural Products 64, 961–964.
Cameron, D.W., Fretrill, G.I., Perlmutter, P., Sasse, J.M., 1984.
Iridoids of Garrya elliptica as plant growth inhibitors. Phytochem-
istry 23, 533–535.
Muhammad, I., Dunbar, D.C., Khan, R.A., Ganzera, M., Khan,
I.A., 2001. Investigation of Una De Gato I. 7- Deoxyloganic
acid and 15N-NMR spectroscopic studies on pentacyclic oxi-
dole alkaloids from Uncaria tomentosa. Phytochemistry 57,
781–785.
Damtoft, S., Jensen, S.R., Nielsen, B.F., 1981. 13C and 1H NMR
spectrocopy as a tool in the configurational analysis of iridoid
glucosides. Phytochemistry 20, 2717–2732.
Otsuka, H., Yoshimura, K., Yamazaki, K., Cantoria, M.C., 1991.
Isolation of 10-O-Acyl iridoid glucosides from a Philippine medic-
inal plant, Oldenlandia corymbosa. Chemical Pharmaceutical Bulle-
tin 39, 2049–2052.
Godin, P., 1954. A newspray reagent for paper chromatography of
polyols and cetoses. Nature (London) 174, 134.
Shukla, Y.N., Lloyd, H.A., Morton, J.F., Kapadia, G.J., 1976. Iridoid
glucosides and other constituents of Paederia foetida. Phytochem-
istry 15, 1989–1990.
Inouye, H., Saito, S., Taguchi, H., Endo, T., 1969a. Zwei neue Iri-
doidglucoside aus Gardenia jasminoides: Gardenosid und Geniposid.
Tetrahedron Letters 28, 2347–2350.
Suzuki, S., Hisamichi, K., Endo, K., 1993. NMR studies and struc-
tural assignment of paederoside. Heterocycles 35, 895–900.
Tran, N.N., 1987. Gop phan vao viec thong ke nhung loai thuc vat co
ich thuoc ho ca phe (Rubiaceae Juss) o Vietnam (Contribution to
the enumeration of useful species of the family Rubiaceae juss in
Vietnam). Journal of Biology 9, 40–44.
Inouye, H., Inouye, S., Shimokawa, N., Okigawa, M., 1969b. Studies
on monoterpene glucosides. VII. Iridoid glucosides of Paederia
scandens. Chemical Pharmaceutical Bulletin 17, 1942–1948.
Inouye, H., Okigawa, M., Shimokawa, N., 1969c. Studies on mono-
terpene glucosides. VIII. Artefacts formed during extraction of
asperuloside and paederoside. Chemical Pharmaceutical Bulletin 17,
1949–1954.