Limonoids and sesquiterpenoids from Amoora tsangii

Article abstract of DOI:10.1021/np070476x

Seven new limonoids, amotsangins A-G (1-7), two known limonoids, and four known sesquiterpenoids were isolated from the twigs and leaves of Amoora tsangii. Their structures were elucidated primarily on the basis of spectroscopic data.

Full text of DOI:10.1021/np070476x

J. Nat. Prod. 2008, 71, 93–97
93
Limonoids and Sesquiterpenoids from Amoora tsangii
Hua-Dong Chen, Sheng-Ping Yang, Shang-Gao Liao, Bo Zhang, Yan Wu, and Jian-Min Yue*
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy
of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai, 201203, People’s Republic of China
ReceiVed September 6, 2007
Seven new limonoids, amotsangins A-G (1-7), two known limonoids, and four known sesquiterpenoids were isolated
from the twigs and leaves of Amoora tsangii. Their structures were elucidated primarily on the basis of spectroscopic
data.
Chemical investigations of the Meliaceae family for structurally
diverse and biologically significant limonoids have been attractive
programs of natural products1 and synthetic chemistry.2 In recent
years, a number of new limonoids have been isolated from the
Meliaceae family by several research groups.3–5 The genus Amoora
(Meliaceae) comprises about 25 species distributed in China, India,
and Malaysia, of which eight species and one variant grow in China.
Hitherto, only one limonoid was reported from this genus.6 Amoora
tsangii (Merr.) X. M. Chen, an economically important timber tree,
is native to Hainan Island of China. It was previously misidentified
as Aglaia tsangii Merr.7 and revised lately as Amoora tsangii.8 The
stem bark of this plant has applications in folklore medicine as a
vermicide.7 Chemical studies on this plant have not been reported
previously.
As a part of our continuous effort to search for novel compounds
from plants of the Meliaceae family, seven new limonoids, namely,
amotsangins A-G (1–7), two known limonoids, DM-39 and DM-
4,9 and four known sesquiterpenoids, 10-hydroxy-15-oxo-R-cadi-
nol,10 11ꢀ-hydroxy-1ꢀ,8R-aromadendrene,11 octahydro-4-hydroxy-
3R-methyl-7-methylene-R-(1-methylethyl)-1H-indene-1-methanol,10 and
eudesm-4(15)-ene-1ꢀ,6R-diol,10 were isolated from the twigs and
leaves of A. tsangii. Herein, we report the isolation and structural
elucidation of these new limonoids.
to the easily distinguishable resonances for an acetyl (δH 2.10, 3H,
s) and a methoxy (δH 3.71, 3H, s) group, the H NMR spectrum
1
also indicated the presence of four tertiary methyls (δH 0.95, 1.00,
1.28, and 1.55, each 3H, s), one secondary methyl (δH 0.76, 3H, d,
J ) 8.6 Hz), one primary methyl (δH 0.79, 3H, t, J ) 7.5 Hz), and
one ꢀ-substituted furan ring (δH 6.17, 7.11, and 7.27, each 1H, s).
The 13C NMR spectrum displayed 34 carbon resonances, which
were classified by DEPT and HSQC experiments as eight methyls,
three sp3 methylenes, seven sp3 methines (three oxygenated), four
sp3 quaternary carbons, four ester carbonyls, an exocyclic double
bond (C-8: δC 136.7; CH2-30: δC 120.8, δH 5.34, 5.22), two
disubstituted double bonds, and one trisubstituted double bond. The
aforementioned NMR data implied that 1 was a ring B-seco
limonoid with a typical ∆8(30) double bond.12
Comparison of the 1H and 13C NMR data of 1 (Tables 1 and 2)
with those of nymania-3 (1a)13 indicated that their structures are
closely related, just differing in the nature of the acyloxy group at
C-12. The presence of a 2-methylbutanoyloxy group was readily
identified by the 1H and 13C NMR data (Tables 1 and 2) and
confirmed by the relevant HMBC correlations within this moiety
(Figure 1a). The key correlations between H-12 and C-1′ further
confirmed the location of the 2-methylbutanoyloxy moiety at C-12.
The complete planar structure of 1 was further verified by the
analysis of its HMBC spectrum. The correlations from two olefinic
protons (δH 5.34, and 5.22, each 1H, s) to C-8, C-9, and C-14
revealed the exocyclic ∆8(30) double bond, typical of a B-seco
limonoid.14 The presence of a 14,15-epoxide was implied by the
chemical shifts of C-14 at δC 71.0 and C-15 at δC 59.4 and was
supported by the mutual HMBC correlations of H2-16/C-15, H-17/
C-15, Me-18/C-14, H-9/C-14, and H2-30/C-14. The HMBC cor-
relations H-1/C-3, C-5, and C-10; H-2/C-3 and C-10; Me-19/C-1;
and a rare 4J correlation Me-28/C-3 indicated that an R,ꢀ-
unsaturated lactone was formed between C-3 and C-4. The sole
methoxy group (δH 3.71; δC 52.3) was placed at C-7 (δC 173.5)
from its cross-peak with this carbon. The HMBC correlation from
H-11 to the carbonyl of the OAc allowed the attachment of the
acetoxy group at C-11.
The relative configuration of the limonoid core was mainly
established by a ROESY experiment (Figure 1b), in which the
correlations Me-18/H-11, Me-18/H-16R, H-11/H-9, and Me-28/H-5
indicated that they were cofacial and were arbitrarily assigned an
R-orientation. The ROESY cross-peaks of H-17 and Me-29, with
H-12 and Me-19, respectively, revealed that H-17, H-12, and Me-
19 were assigned a ꢀ-orientation. The large coupling constant (J11, 12
) 10.8 Hz) showed a 1,2-diaxial relationship between H-11 and
H-12, consistent with the previous R- and ꢀ-assignments for these
Results and Discussion
Amotsangin A (1) was obtained as a white, amorphous powder.
Its molecular formula was determined by the HREIMS ion at m/z
612.2947 [M]+ as C34H44O10 (calcd 612.2934), indicating the
presence of 13 degrees of unsaturation. Its ESIMS ions (in positive
mode) at 635.4 [M + Na]+ and 1247.7 [2 M + Na]+ further secured
the molecular formula. The strong IR absorptions at 1747, 1728,
and 1699 cm-1 showed the presence of carbonyl groups. In addition
two protons.5 The ROESY correlations of H-6a (δ 2.29)/Me-19
a,f
and H-6b (δ 2.18)/Me-28 indicated that CH2-6 was approximately
equatorial toward the ꢀ-face. The chemical shifts of C-14 and C-15
of 1 were nearly identical to those of nymania-3 (1a),13 suggesting
that the 14,15-epoxide was ꢀ-oriented, and this was confirmed by
* Corresponding author. Tel: +86-21-50806718. Fax: +86-21-50806718.
E-mail: jmyue@mail.shcnc.ac.cn.
10.1021/np070476x CCC: $40.75
2008 American Chemical Society and American Society of Pharmacognosy
Published on Web 12/14/2007

94 Journal of Natural Products, 2008, Vol. 71, No. 1
Chen et al.
Table 1. 1H NMR Data (400 MHz, CDCl3) for Compounds 1–7
1
2
3
4
proton
δH (J in Hz)
δH (J in Hz)
δH (J in Hz)
δH (J in Hz)
1
2
5
6a
6b
9
6.92, d (13.2)
6.25, d (13.2)
3.27, d (9.2)
2.29, d (16.6)
2.18, dd (16.6, 9.2)
3.06, d (7.3)
5.62, dd, (10.8, 7.3)
5.84, d, (10.8)
3.86, s
2.22, dd (14.0, 6.9)
1.81, dd (14.0, 10.9)
3.07, dd (10.9, 6.9)
0.95, s
1.00, s
7.11, s
6.17, s
7.27, s
1.28, s
1.55, s
5.34, s
5.22, s
6.93, d (12.9)
6.26, d (12.9)
3.29, d (9.2)
2.29, d (16.8)
2.18, dd (16.8, 9.2)
3.07, d (7.3)
5.62, dd (10.9, 7.3)
5.83, d (10.9)
3.86, s
2.22, dd (13.8, 7.0)
1.81, dd (13.8, 11.1)
3.00, dd (11.1, 7.0)
0.95, s
1.00, s
7.11, s
6.17, s
7.28, s
1.29, s
1.55, s
5.34, s
5.22, s
6.95, d (13.1)
6.28, d (13.1)
3.31, d (8.8)
2.30, d (17.2)
2.20, dd (17.2, 8.8)
3.08, d (7.1)
5.69, dd (11.0, 7.1)
6.00, d (11.0)
3.86, s
2.27, dd (14.0, 7.1)
1.84, dd (14.0, 11.0)
3.06, dd (11.0, 7.1)
0.97, s
1.02, s
7.12, s
6.17, s
7.33, s
1.30, s
1.58, s
5.37, s
5.25, s
6.93, d (12.9)
6.27, d (12.9)
3.33, d (9.1)
2.28, d (17.3)
2.18, dd (17.3, 9.1)
3.07, d (7.3)
5.60, dd (10.8, 7.3)
5.86, d (10.8)
3.88, s
2.22, dd (13.3, 7.0)
1.83, dd (13.3, 10.4)
3.04, dd (10.4, 7.0)
0.93, s
1.01, s
7.11, s
6.15, s
7.30, s
1.29, s
1.56, s
5.35, s
5.23, s
11
12
15
16ꢀ
16R
17
18
19
21
22
23
28
29
30a
30b
OMe
OAc
2′
3.71, s
2.10, s
1.94, m
3.71, s
2.09, s
2.17, m
3.73, s
2.14, s
3.45, s
3.72, s
2.10, s
1.96, m
3′a
3′b
4′
1.41, m
1.17, m
0.79, t (7.5)
0.85, d (7.1)
1.41, m
0.93, t (7.6)
0.82, d (7.1)
1.40, m
1.23, m
5′
6′
0.76, d (8.6)
0.82, t (7.1)
0.69, d (6.6)
5
6
7
proton
δ
H (J in Hz)
δH (J in Hz)
δH (J in Hz)
1
2
7.00, d (13.1)
6.35, d (13.1)
6.96, d (12.9)
6.34, d (12.9)
5.11, d (7.0)
3.28, dd (15.9, 7.0)
3.19, d (15.9)
2.61, d (8.4)
2.83, d (14.8)
2.61, dd (14.8, 8.4)
2.96, s
4.98, s
5.19, s
3.71, s
5
6a
6b
9
11
12
15
3.35, d (8.9)
2.32, d (16.6)
2.20, dd (16.6, 8.9)
3.13, d (7.3)
5.77, d (10.8, 7.3)
6.10, d (10.8)
3.91, s
3.32, d (8.4)
2.32, d (16.6)
2.23, dd (16.6, 8.4)
3.19, d (7.5)
5.89, dd (10.6, 7.5)
6.13, d (10.6)
3.92, s
16ꢀ
16R
17
2.26, dd (13.6, 6.9)
1.86, dd (13.6, 11.2)
3.13, dd (11.2, 6.9)
1.00, s
2.28, dd (14.0, 7.0)
1.86, dd (14.0, 10.7)
3.14, dd (10.7, 7.0)
1.02, s
2.24, dd (13.1, 6.8)
2.04, dd (13.1, 11.3)
2.90, dd (11.3, 6.8)
0.96, s
18
19
1.04, s
1.06, s
1.46, s
21
7.00, s
6.98, s
7.09, s
22
6.05, s
6.05, s
6.14, s
23
7.01, s
6.98, s
7.28, s
28
1.28, s
1.28, s
1.47, s
29
1.57, s
1.56, s
1.56, s
30a
30b
OMe
OAc
5.39, s
5.26, s
3.70, s
1.89, s
5.41, s
5.28, s
3.71, s
1.43, s
2.05, s
2.16, s
2′
2.09, m
3′a
3′b
4′
5′
6′
7.75, dd (8.1, 1.4)
7.74, dd (8.1, 1.3)
1.40, m
1.17, m
0.73, t (7.5)
1.05, d (6.9)
7.33, dd (8.1, 7.4)
7.48, tt, (7.4, 1.4)
7.33, dd (8.1, 7.4)
7.75, dd (8.1, 1.4)
7.32, dd (8.1, 7.6)
7.47, tt, (7.6, 1.4)
7.32, dd (8.1, 7.6)
7.74, dd (8.1, 1.3)
7.98 (s)
7′
OCHO
the ROESY correlation between H-15 and H-30a, which was also
observed in the structural elucidation of a known compound, 11-
epi-21-hydroxytoonacilide, with a ꢀ-oriented 14,15-epoxide moi-
ety.12 The structure of 1 was thus elucidated.
Comparison of the NMR and MS data of amotsangins B-E (2–5)
with those of 1 showed that these compounds differed in the nature
of the C-12 acyloxy groups (Experimental Section and Tables 1
and 2). The presence of a methylpropanoyloxy group in 2 was

Limonoids and Sesquiterpenoids from Amoora tsangii
Journal of Natural Products, 2008, Vol. 71, No. 1 95
Table 2. 13C NMR Data (100 MHz, CDCl3) for Compounds
1–7
S5, S6). After preparative TLC purification, the ESIMS spectrum
and HPLC retention time (by coinjection) of the major compound
were consistent with those of compound 5 (Supporting Information
S7-S9). The structure of 6 was therefore determined.
position
1
2
3
4
5
6
7
1
2
148.5 148.5 148.4 148.5 148.5 148.2
122.0 122.0 122.2 122.0 122.1 122.6
70.9
34.8
Amotsangin G (7) gave a molecular formula of C35H46O11 with
13 degrees of unsaturation, as determined by HREIMS at m/z
642.3033 [M]+ (calcd 642.3040). The ESIMS in the positive mode
showed pseudomolecular ions at 643.4 [M + H]+ and 665.3 [M +
Na]+ supporting this assignment. The IR absorptions at 1755 and
1720 cm-1 revealed the presence of carbonyl groups. The 13C NMR
of 7 displayed 35 signals, which were further classified by DEPT
and HSQC spectra as nine methyls, four methylenes, 11 methines,
and 11 quaternary carbons. The presence of five tertiary methyls
(δH 0.96, 1.43, 1.46, 1.47, and 1.56, each 3H, s), two acetyls (δH
2.05, 2.16; δC 20.9, 21.2, 168.5, and 169.1), one 2-methylbutanoyl-
oxy group [δH 0.73 (3H, t, J ) 7.5 Hz), 1.05 (3H, d, J ) 6.9 Hz),
1.17 (m), 1.40 (m), and 2.09 (m); δC174.9, 40.8, 26.1, 15.5, and
11.4], and a ꢀ-substituted furan ring (δH 6.14, 7.09, 7.28; δC 111.7,
3
166.5 166.5 166.5 166.6 166.5 166.9 169.3
4
5
6
83.5
50.0
34.9
83.5
50.0
34.9
83.7
50.0
34.9
83.5
49.9
34.9
83.5
50.0
35.0
83.5
50.6
35.0
84.2
50.9
38.6
7
173.5 173.5 173.4 173.5 173.4 173.5 207.1
8
9
136.7 136.7 136.5 136.6 136.8 136.6
45.1
44.0
44.4
75.5
80.6
45.1
67.8
56.2
33.5
41.5
14.8
17.0
53.2
46.2
70.9
73.6
45.5
71.0
59.4
34.0
37.6
13.6
22.6
53.2
46.2
71.0
73.7
45.4
71.0
59.4
33.8
37.6
13.6
22.6
53.5
46.3
70.4
72.9
45.6
71.0
59.5
34.0
37.7
13.6
22.8
53.2
46.2
71.0
74.0
45.1
71.0
59.5
33.5
37.7
13.5
22.6
53.3
46.3
71.1
75.1
45.4
71.2
59.7
33.3
38.0
13.6
22.4
53.3
46.2
71.1
74.7
45.5
71.1
59.7
33.5
37.9
13.7
22.4
10
11
12
13
14
15
16
17
18
19
20
21
22
23
28
29
30
OMe
OAc
1
122.9, 141.1, and 142.3) were indicated by the H and 13C NMR
data. The aforementioned data suggested that compound 7 was also
a limonoid.16
122.1 122.1 121.9 121.1 122.1 122.6 121.9
140.5 140.4 140.5 140.3 140.3 140.4 141.1
111.3 111.2 111.0 111.1 111.0 111.0 111.7
142.3 142.4 142.7 142.4 142.3 142.3 142.3
The planar structure of 7 was constructed by extensive analysis
of its 1D and 2D NMR spectra. In the HMBC spectrum (Figure
2a), H-5, H2-6, H-9, and Me-30 showed correlations with the ketone
carbonyl at δC 207.1, indicating that compound 7 had an intact B
ring with a ketone group at C-7. An oxygenated methine (δH 4.98,
δC 75.5) bearing an acetoxy group was assigned to C-11 on the
basis of the HMBC correlations from H-11 to C-8, C-9, C-10, and
the carbonyl carbon of OAc at δC 169.1. The HMBC correlation
between H-12 at δH 5.19 and the carbonyl signal at δC 174.9 of
the 2-methylbutanoyloxy group facilitated placement of this group
at C-12 (δC 80.6). The HMBC correlation from the methyl protons
of the remaining acetoxy group to C-1 at δC 70.9 allowed the
attachment of OAc to C-1, which also showed HMBC correlations
with H2-2 and Me-19. The presence of a 14,15-epoxide was
assigned on the basis of the chemical shifts [δH 3.86, H-15; δC
59.4 (C-15) and 71.0 (C-14)], which was supported by the HMBC
correlations of H2-16 with C-15 and C-14, and 18-Me and 30-Me
with C-14. One ester carbonyl at δ 169.3 and one oxygenated
quaternary carbon at δ 84.2 were assigned to C-3 and C-4,
respectively, by the mutual HMBC correlations from H2-2 and H-1
to C-3, and from Me-28 (and 29) to C-4, indicating that a lactone
30.2
22.3
30.2
22.4
30.2
22.3
30.2
22.3
30.2
22.7
30.2
22.9
23.2
33.8
21.2
120.8 120.9 121.1 120.9 121.0 121.2
52.3
20.6
52.3
20.5
52.3
20.8
52.3
20.3
52.3
20.2
52.3
20.9
168.5
21.2
170.4 170.3 170.3 170.3 170.4
169.1
1′
174.8 175.3 175.0 173.0 165.6 165.5 174.9
2′
3′
4′
5′
6′
7′
OCHO
41.1
25.9
11.7
15.3
33.9
18.2
18.4
75.3
37.8
26.2
11.6
13.0
27.4 129.7 129.5
8.7 129.5 129.6
128.2 128.2
132.8 132.9
128.2 128.2
129.5 129.6
160.1
40.8
26.1
11.4
15.5
evidenced by the 1D NMR data [C-1′: δC 175.3; CH-2′: δC 33.9,
δH 2.17 (m); CH3-3′: δC 18.2, δH 0.85 (3H, d, J ) 7.1 Hz); CH3-
4′: δC 18.4, δH 0.82 (3H, d, J ) 7.1 Hz)]. In the same way, the
acyloxy groups at C-12 of 3-5 were determined as follows: a
2-hydroxy-3-methylpentanoyloxy for 3 [C-1′: δC 175.0; CH-2′: δC
75.3, δH 3.45 (s); CH-3′: δC 37.8, δH 1.41 (m); CH2-4′: δC 26.2,
δH 1.40 (m), 1.23 (m); CH3-5′: δC 11.6, δH 0.82 (3H, t, J ) 7.1
4
existed between C-3 and C-4, which was confirmed by a weak J
HMBC correlation between Me-28 and C-3.
The relative configuration of 7 was determined by a ROESY
experiment (Figure 2b). The ROESY correlations of Me-19/H-1,
Me-19/H-2ꢀ, Me-19/Me-29, Me-19/H-6ꢀ, H-6ꢀ/Me-30, and Me-
29/H-2ꢀ indicated that these methyl groups and protons were
cofacial and were randomly assigned as the ꢀ-orientation. Subse-
quently, the ROESY correlations of H-5/Me-28, Me-28/H-6R, H-5/
H-9, H-9/H-11, and H-9/Me-18 revealed that Me-18, H-5, H-9, and
Me-28 were in an R-orientation; the ROESY correlations of H-17/
H-12 and H-17/H-16ꢀ indicated that H-12 and H-17 were ꢀ-ori-
ented. The 14,15-epoxide was assigned as ꢀ-oriented on the basis
of the chemical shifts of H-15, C-14, and C-15, which were nearly
identical to those of 1-6. This assignment was further supported
by the similarity of the chemical shifts of C-14 and C-15 with those
of a known compound, 11ꢀ,12R-diacetoxy-1-deoxo-14ꢀ,15ꢀ-epoxy-
3ꢀ-hydroxy-2-oxo-neotecleanin.17
Hz); CH3-6′: δC 13.0, δH 0.69 (3H, d, J ) 6.6 Hz)],15
a
propanoyloxy for 4 [C-1′: δC 173.0; CH2-2′: δC 27.4, δH 1.96 (m);
CH3-3′: δC 8.7, δH 0.93 (3H, t, J ) 7.6 Hz)], and a benzoyloxy for
5 [C-1′: δC 165.6; C-2′: δC 129.7; CH-3′, 7′: δC 129.5, δH 7.75
(1H, dd, J ) 8.1, 1.4 Hz); CH-4′, 6′: δC 128.2, δH 7.33 (1H, dd, J
) 8.1, 7.4 Hz); CH-5′: δC 132.8, δH 7.48 (1H, tt, J ) 7.4, 1.4
Hz)]. The attachment of the acyloxy groups to C-12 of compounds
2-5 was confirmed by key HMBC correlations between H-12 and
C-1′ of each acyloxy group (Supporting Information), respectively.
Thus the structures of amotsangins B-E were assigned as 2–5,
respectively.
Amotsangin F (6) gave a molecular formula of C35H38O10, as
deduced from HREIMS at m/z 618.2482 (calcd for C35H38O10,
618.2465). The 1H and 13C NMR data of amotsangin F (6) showed
high similarity to those of 5, except that the acetoxy group was
replaced by a formyloxy group (δH 7.98; δC 160.1). To confirm
this, compound 6 was treated with aqueous NaHCO3 (5%, 0.5 mL)
in MeOH (3 mL) at room temperature for 30 min. The mixture
was then reacted with Ac2O in dried pyridine overnight to give a
crude product, whose HPLC-ESIMS showed a major peak at 2.27
min with a pseudomolecular ion at m/z 633 [M + H]+ corresponding
to the molecular formula of compound 5 (Supporting Information
Six known compounds, DM-3,8 DM-4,8 10-hydroxy-15-oxo-R-
cadinol,9 11ꢀ-hydroxy-1ꢀ,8R-aromadendrene,10 octahydro-4-hy-
droxy-3R-methyl-7-methylene-R-(1-methylethyl)-1H-indene-1-metha-
nol,9 and eudesm-4(15)-ene-1ꢀ,6R-diol,9 were identified by
comparison of their spectroscopic data with literature data.
Experimental Section
General Experimental Procedures. Optical rotations were deter-
mined on a Perkin-Elmer 341 polarimeter. UV spectra were recorded

96 Journal of Natural Products, 2008, Vol. 71, No. 1
Chen et al.
Figure 1. (a) Selected HMBC (HfC) correlations of 1; (b) key ROESY (HTH) correlations of 1.
Figure 2. (a) Selected HMBC (HfC) correlations of 7; (b) key ROESY (HTH) correlations of 7.
on a Shimadzu UV-2550 spectrophotometer. IR spectra were recorded
on a Perkin-Elmer 577 spectrometer with KBr disks. NMR spectra were
measured on a Bruker AM-400 spectrometer. EIMS and HREIMS (70
eV) were carried out on a Finnigan MAT 95 mass spectrometer, and
ESIMS was obtained on an Esquire 3000plus (Bruker Daltonics). Si
gel (200–300 mesh) and Si gel H (Qingdao Haiyang Chemical Co.
Ltd.), C18 reverse-phased Si gel (150–200 mesh, Merck), MCI gel
(CHP20P, 75–150 µm, Mitsubishi Chemical Industries Ltd.), and
Sephadex LH-20 gel (Amersham Biosciences) were used for column
chromatography. Precoated Si gel GF254 plates (Qingdao Marine
Chemical Plant, Qingdao, China) were used for TLC. All solvents used
were of analytical grade (Shanghai Chemical Plant, Shanghai, China).
HPLC-MS was carried out on an Agilent Lcmsd vl mass spectrom-
eter with an Agilent 1100 Series HPLC system, and the HPLC column
was a XTerra MS reversed-phase C18 Si gel (2.1 × 50 mm, 5.0 µm).
The mobile phase was 10–95% CH3CN in H2O (10 mmol of NH4HCO3)
with a flow rate of 1.1 mL/min, and the column chamber was kept at
ca. 50 °C for analysis of all compounds.
Plant Material. The twigs and leaves of Amoora tsangii were
collected from Hainan Island of China in February 2004 and authen-
ticated by Prof. Shi-Man Huang, Department of Biology, Hannan
University of China. A voucher specimen has been deposited in
Shanghai Institute of Materia Medica, Chinese Academy of Sciences
(accession number AMTA-tzzf-02Y).
Extraction and Isolation. The air-dried powder of twigs and leaves
of A. tsangii (9 kg) was extracted three times with 95% EtOH at room
temperature to provide an extract (800 g), which was partitioned
between EtOAc and H2O to give an EtOAc-soluble fraction (165 g).
Fractionation of the EtOAc-soluble fraction on a column of MCI gel
(MeOH/H2O, 40/60 f 90/10, v/v) afforded three fractions, 1–3. Fraction
2 (28 g) was chromatographed on a Si gel column eluted with a mixture
of petroleum ether/acetone (25:1 to 100% acetone, v/v) in gradient to
give seven major fractions, 2a-2g. Fraction 2a (283 mg) was separated
on a Si gel column (petroleum ether/EtOAc, 2:1, v/v) to obtain a major
compound, which was purified by column chromatography (RP-18 Si
gel; MeOH/H2O, 75/25, v/v) to give 11ꢀ-hydroxy-1ꢀ,8R-aromadendrene
(9 mg). Fraction 2b (2.3 g) was subjected to Si gel column chroma-
tography (petroleum ether/acetone, 10:1, v/v) to give two major
subfractions, each of which was purified successively on a reversed-
phase Si gel column (MeOH/H2O, 70/30, v/v) and Si gel column
(petroleum ether/EtOAc, 2:1, v/v) to obtain 1 (40 mg) and eudesm-
4(15)-ene-1ꢀ,6R-diol (7 mg), respectively. Fraction 2d (2.5 g) was
separated on a Si gel column (petroleum ether/EtOAc, 2:1, v/v) to afford
three major fractions, 2d1 (140 mg), 2d2 (430 mg), and 2d3 (300 mg).
Fractions 2d1–2d3 were respectively purified by column chromatog-
raphy over a reversed-phase Si gel column (MeOH/H2O, 70/30, v/v)
and then a Si gel column (petroleum ether/2-propanol, 10:1, v/v) to
afford 2 (14 mg), 3 (6 mg), and 4 (9 mg). Fraction 2e (1.2 g) was
separated by column chromatography over a Si gel column (petroleum
ether/2-propanol, 10:1, v/v) to give three major subfractions, and each
of them was then purified on a reversed-phase RP-18 Si gel column
(MeOH/H2O, 70/30, v/v) to yield 6 (4 mg), 5 (9 mg), and 7 (229 mg),
respectively. Fraction 2f (330 mg) was subjected to a Si gel column
(petroleum ether/EtOAc, 2:1, v/v) to give two subfractions, 2f1 and
2f2. Fraction 2f1 was separated by an RP-18 reversed-phase Si gel
column (MeOH/H2O, 70/30, v/v) to give two major compounds, each
of which was then chromatographed on a column of Sephadex LH-20
(MeOH) to give DM-3 (6 mg) and DM-4 (9 mg), respectively. Fraction
2f2 was dealt with in the same way as fraction 2f1 to obtain two

Limonoids and Sesquiterpenoids from Amoora tsangii
Journal of Natural Products, 2008, Vol. 71, No. 1 97
1
compounds, 10-hydroxy-15-oxo-R-cadinol (5 mg) and octahydro-4-
hydroxy-3R-methyl-7-methylene-R-(1-methylethyl)-1H-indene-1-metha-
nol (5 mg).
1026, 604 cm-1; H NMR (CDCl3, 400 MHz) see Table 1; 13C NMR
(CDCl3, 100 MHz) see Table 2; positive-ion ESIMS m/z643.4 [M +
H]+, 665.3 [M + Na]+; EIMS m/z 642 (40), 582 (35), 481 (76), 421
(100), 225 (100), 107 (26), 85 (29), 57 (100); HREIMS m/z 642.3033
(calcd for C35H46O11, 642.3040).
Amotsangin A (1): white powder; [R]21D +108.0 (c 0.15, CHCl3);
UV (MeOH) λmax (log ꢀ) 215.8 (3.14), 203.4 (3.13), 201.0 (3.13) nm;
IR (KBr) Vmax 3435 (w br, water), 3128, 2958, 2933, 1747, 1728, 1699,
1
1460, 1373, 1219, 1124, 1038, 824, 606 cm-1; H NMR (CDCl3, 400
Acknowledgment. Financial support from the Key Project of
National Natural Science Foundation (Grant No. 30630072) and from
the Shanghai Municipal Scientific Foundation (Grant No. 06DZ22028)
of the People’s Republic of China is gratefully acknowledged. We thank
Prof. S.-M. Huang for the collection and identification of the plant
material.
MHz) see Table 1; 13C NMR (CDCl3, 100 MHz) see Table 2; positive-
ion ESIMS m/z635.4 [M + Na]+, 1247.7 [2 M + Na]+; EIMS m/z 612
(2), 552 (2), 387 (4), 225 (100), 207 (36), 135 (31), 107 (35), 57 (60);
HREIMS m/z 612.2947 (calcd for C34H44O10, 612.2934).
Amotsangin B (2): white powder; [R]21D +110.0 (c 0.11, CHCl3);
UV (MeOH) λmax (log ꢀ) 215.0 (3.24), 198.6 (3.23) nm; IR (KBr) Vmax
3446 (water), 2974, 1747, 1734, 1699, 1373, 1221, 1126, 1040, 824,
604 cm-1; 1H NMR (CDCl3, 400 MHz) see Table 1; 13C NMR (CDCl3,
100 MHz) see Table 2; positive-ion ESIMS m/z 621.3 [M + Na]+,
1219.5 [2 M + Na]+; EIMS m/z 598 (1), 582 (16), 421 (60), 225 (100),
207 (42), 135 (42), 107 (55), 57 (42); HREIMS m/z 598.2796 (calcd
for C33H42O10, 598.2778).
Supporting Information Available: Selected HMBC correlations
of amotsangins B-E (2–5); HPLC-ESIMS monitoring of the transfor-
mation of compound 6 to 5; IR, EIMS, and H and 13C NMR spectra
1
of amotsangins A-G (1–7); 2D NMR spectra of amotsangins A-E
(1–5) and amotsangin G (7). This material is available free of charge
via the Internet at http://pubs.acs.org.
Amotsangin C (3): white powder; [R]21D +131.0 (c 0.10, CHCl3);
UV (MeOH) λmax (log ꢀ) 215.2 (3.06), 198.2 (3.06) nm; IR (KBr) Vmax
3444 (OH), 2962, 2933, 1745, 1701, 1373, 1277, 1252, 1221, 1128,
References and Notes
1
1039, 604 cm-1; H NMR (CDCl3, 400 MHz) see Table 1; 13C NMR
(1) (a) Champagne, D. E.; Koul, O.; Isman, M. B.; Scudder, G. G. E.;
Towers, G. H. N. Phytochemistry 1992, 31, 377–394. (b) Mulholland,
D. A.; Parel, B.; Coombes, P. H. Curr. Org. Chem. 2000, 4, 1011–
1054.
(2) Trudeau, S.; Morken, J. P. Org. Lett. 2005, 7, 5465–5468.
(3) Yuan, X. H.; Li, B. G.; Zhou, M.; Qi, H. Y.; Zhang, G. L. Org. Lett.
2005, 7, 5051–5053.
(CDCl3, 100 MHz) see Table 2; positive-ion ESIMS m/z 643.4 [M +
H]+, 1307.7 [2 M + Na]+; negative-ion ESIMS m/z 687.6 [M +
HCOOH - H]-; EIMS m/z 642 (5), 582 (4), 540 (8), 421 (60), 225
(100), 207 (41), 135 (35), 107 (59), 57 (16); HREIMS m/z642.3050
(calcd for C35H46O11, 642.3040).
Amotsangin D (4): white powder; [R]21D +125.0 (c 0.12, CHCl3);
UV (MeOH) λmax (log ꢀ) 216.0 (3.15), 200.4 (3.13), 198.8 (3.14) nm;
IR (KBr) Vmax 3446 (water), 2987, 2955, 1749, 1701, 1371, 1223, 1128,
(4) Wu, J.; Xiao, Q.; Huang, J.; Xiao, Z.; Qi, S.; Li, Q.; Zhang, S. Org.
Lett. 2004, 6, 1841–1844.
(5) (a) Wang, X. N.; Yin, S.; Fan, C. Q.; Wang, F. D.; Lin, L. P.; Ding,
J.; Yue, J. M. Org. Lett. 2006, 8, 3845–3848. (b) Yin, S.; Fan, C. Q.;
Wang, X. N.; Lin, L. P.; Ding, J.; Yue, J. M. Org. Lett. 2006, 8, 4935–
4938. (c) Yin, S.; Wang, X. N.; Fan, C. Q.; Liao, S. G.; Yue, J. M.
Org. Lett. 2007, 9, 2353–2356. (d) Fan, C. Q.; Wang, X. N.; Yin, S.;
Zhang, C. R.; Wang, F. D.; Yue, J. M. Tetrahedron 2007, 63, 6741–
6747. (e) Yin, S.; Wang, X. N.; Fan, C. Q.; Lin, L. P.; Ding, J.; Yue,
J. M. J. Nat. Prod. 2007, 70, 682–685. (f) Wang, X. N.; Yin, S.; Fan,
C. Q.; Lin, L. P.; Ding, J.; Yue, J. M. Tetrahedron 2007, 63, 8234–
8241.
(6) Agnihotri, V. K.; Srivastava, S. D.; Srivastava, S. K. Planta Med.
1987, 53, 298–299.
(7) Chen W. Y.; Chang, C. C.; Chen. F. H. In Flora Hainanica (Hainan
Zhiwu Zhi); Science Press: Beijing, 1974; Vol. 3, pp 66–67.
(8) Chen, S. K.; Chen, B. Y.; Li, H. In Flora Reipublicae Popularis Sinicae
(Zhongguo Zhiwu Zhi); Science Press: Beijing, 1997; Vol. 43 (3), pp
80–87.
(9) Connolly, J. D.; Labbé, C.; Rycroft, D. S.; Okorie, D. A.; Taylor,
D. A. H. J. Chem. Res. (M) 1979, 2858–2886.
(10) Zhang, H. J.; Tan, G. T.; Santarsiero, B. D.; Mesecar, A. D.; Hung,
N. V.; Cuong, N. M.; Soejarto, D. D.; Pezzuto, J. M.; Fong, H. H. S.
J. Nat. Prod. 2003, 66, 609–615.
(11) Tringali, C.; Piattelli, M.; Spatafora, C. Phytochemistry 1995, 40, 827–
831.
(12) Cheplogoi, P. K.; Mulholland, D. A. Phytochemistry 2003, 62, 1173–
1178.
1
1026, 604 cm-1; H NMR (CDCl3, 400 MHz) see Table 1; 13C NMR
(CDCl3, 100 MHz) see Table 2; positive-ion ESIMS m/z 585.2 [M +
H]+, 1191.5 [2 M + Na]+; EIMS m/z 584 (7), 451 (12), 225 (100),
207 (37), 135 (36), 107 (49), 97 (36), 57 (52); HREIMS m/z584.2620
(calcd for C32H40O10, 584.2621).
Amotsangin E (5): white powder; [R]21D +100.0 (c 0.11, CHCl3);
UV (MeOH) λmax (log ꢀ) 224.8 (3.23), 199.4 (3.40) nm; IR (KBr) Vmax
3446 (water), 2955, 2989, 1749, 1728, 1701, 1373, 1275, 1219, 1128,
1
1028, 712 cm-1; H NMR (CDCl3, 400 MHz) see Table 1; 13C NMR
(CDCl3, 100 MHz) see Table 2; positive-ion ESIMS m/z 655.2 [M +
Na]+, 1288.3 [2 M + Na + H]+; EIMS m/z 632 (1), 417 (6), 225 (10),
105 (100), 77 (15); HREIMS m/z 632.2605 (calcd for C36H40O10,
632.2621).
Amotsangin F (6): white powder; [R]21 +29.0 (c 0.11, CHCl3);
D
UV (MeOH) λmax (log ꢀ) 226.2 (3.14), 199.4 (3.36) nm; IR (KBr) Vmax
3433 (moderate to strong, water), 2926, 2852, 1734, 1450, 1383, 1273,
1
1121, 1028, 712 cm-1; H NMR (CDCl3, 400 MHz) see Table 1; 13C
NMR (CDCl3, 100 MHz) see Table 2; positive-ion ESIMS m/z 641.3
[M + Na]+, 1259.5 [2 M + Na]+; negative-ion ESIMS m/z 663.5 [M
+ HCOOH - H]-; EIMS m/z 618 (1), 417 (4), 225 (11), 105 (100),
77 (16); HREIMS m/z 618.2482 (calcd for C35H38O10, 618.2465).
Chemical Transformation of 6 to 5. Compound 6 (1 mg) was
dissolved in 3 mL of MeOH, and then 0.5 mL of aqueous NaHCO3
(5%, wt/v) was added. The mixture was stirred for 30 min at room
temperature. Water (2 mL) was then added, and the mixture was
extracted with EtOAc (3 × 1 mL) to obtain the crude product. After
the removal of the EtOAc 0.4 mL of dried pyridine and 0.4 mL of
Ac2O were added, and the mixture was then kept overnight at room
temperature. After workup, the residue was purified by TLC (CHCl3/
MeOH, 20:1, v/v) to yield 5 (0.33 mg, 32.6%).
(13) Govindachari, T. R.; Suresh, G.; Krishna Kumari, G. N.; Rajamannar,
T.; Partho, P. D. Fitoterapia 1999, 70, 83–86.
(14) Mulholland, D. A.; Monkhe, T. V.; Coombes, P. H.; Rajab, M. S.
Phytochemistry 1998, 49, 2585–2590.
(15) Adul, G. O.; Bentley, M. D.; Benson, B. W.; Huang, F.-Y.; Gelbaum,
L.; Hassanali, A. J. Nat. Prod. 1993, 56, 1414–1417.
(16) Ayafor, J. F.; Kimbu, S. F.; Ngadjui, B. T.; Akam, T. M.; Dongo, E.;
Sondengam, B. L. Tetrahedron 1994, 50, 9343–9354.
(17) Ndung’u, M.; Hassanali, A.; Hooper, A. M.; Chhabra, S.; Miller, T. A.;
Paul, R. L.; Torto, B. Phytochemistry 2003, 64, 817–823.
Amotsangin G (7): white powder; [R]21 -17.0 (c 0.13, CHCl3);
D
UV (MeOH) λmax (log ꢀ) 211.0 (2.71), 197.4 (2.65) nm; IR (KBr) νmax
3445 (moderate br, water), 2976, 1755, 1720, 1462, 1373, 1229, 1119,
NP070476X