Chemical constituents from Sarcopyramis nepalensis Wall

Article abstract of DOI:10.1016/j.phytol.2014.02.011

One new megastigmane glycoside 1 and two new terpenic glycosides 2 and 3, along with three known compounds, roseoside, pumilaside A, and terminolic acid were isolated from Sarcopyramis nepalensis Wall. The structures of these new compounds were elucidated on the basis of 1D, 2D NMR, MS spectroscopic analysis, and chemical methods.

Full text of DOI:10.1016/j.phytol.2014.02.011

Phytochemistry Letters 8 (2014) 101–104
Contents lists available at ScienceDirect
Phytochemistry Letters
journal homepage: www.elsevier.com/locate/phytol
Chemical constituents from Sarcopyramis nepalensis Wall
Wei-bin Wei b,1, Yu-jie Huang a,1, Hai-jian Cong a, Shu-wei Zhang a,
Da-ren Pan b, Li-jiang Xuan a,
*
a State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Zhangjiang Hi-Tech Park,
Shanghai 201203, People’s Republic of China
b School of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, People’s Republic of China
A R T I C L E I N F O
A B S T R A C T
Article history:
One new megastigmane glycoside 1 and two new terpenic glycosides 2 and 3, along with three known
compounds, roseoside, pumilaside A, and terminolic acid were isolated from Sarcopyramis nepalensis
Wall. The structures of these new compounds were elucidated on the basis of 1D, 2D NMR, MS
spectroscopic analysis, and chemical methods.
Received 24 September 2013
Received in revised form 15 February 2014
Accepted 21 February 2014
Available online
ß 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
Keywords:
Sarcopyamis nepalensis
Melastomataceae
Megastigmane
Terpenic glycosides
1. Introduction
terminolic acid (Li et al., 2002). To the best of our knowledge, this
is the first report on glycosides content of this plant.
The genus Sarcopyramis (Melastomataceae) contains 9 species
widely distributed in China, some of which have been used as
traditional Chinese medicine (TCM). The characteristic chemical
composition of this genus is flavonoids, steroids, fatty acids, and
phenolic acids (Wang et al., 2008; Wan et al., 2009). Sarcopyramis
nepalensis Wall has been widely used for the treatment of
oxyhepatitis, chronic hepatitis, cough and rheumatic arthralgia in
China (The Editorial Committee of the Administration Bureau of
Traditional Chinese Medicine, 1999). To date, phytochemical
investigations on S. nepalensis have led to the isolation of
polysaccharides, flavonoids, as well as phenolic acids from this
species (Wang et al., 2009; Zhang et al., 2011). Biological assays of
S. nepalensis extracts have shown moderate activities on
antioxidation, anti-bacteria and prevention of liver injury (Li
et al., 2007). This paper reports the isolation and structural
elucidation of one new megastigmane glycoside sarconepaside A
(1) and two new terpenic glycosides sarconepasides B and
C (2 and 3) (Fig. 1), along with three known compounds, roseoside
(Yamano and Ito, 2005), pumilaside A (Kitajima et al., 2000), and
2. Results and discussion
Sarconepaside A (1) was obtained as a white amorphous
powder. HRESIMS revealed a molecular formula of C19H32O8 (m/z
411.1994 [M+Na]+, C19H32O8Na+, calcd. 411.1995). The IR spec-
trum of 1 showed absorption bands at 3407, 1637, 1076, and
1037 cmꢀ1 assignable to hydroxy,
a
,
b
-unsaturated carbonyl, and
ether group, respectively. Hydrolysis of 1 liberated
D-glucose,
giving a positive optical rotation a2D0 ¼ þ47:2 (c = 0.1, H2O). The
sugar unit was determined as
b-D-glucose from the anomeric
proton at dH 4.55 (J = 7.8 Hz). According to the 13C NMR data, the
remaining thirteen signals can be classified as four methyls (dC
30.6,
46.5), three methines
oxygenerated), one quaternary carbon (
d
C 28.4,
d
C 27.7 and
d
(
C 22.7), two methylenes (
dC 78.3, dC 70.3 and dC 58.8, two
C 37.8), one trisubstituted
dC 49.4 and dC
d
double bond (dC 165.0 and dC 129.4) and one carbonyl group (dC
203.9). In the HMBC spectrum, the correlations of H-2/C-1 and C-3;
H-4/C-2, C-6, and C-13; H-6/C-1, C-4, and C-5; H3-11/C-1, C-2, and
C-6; H3-12/C-1, C-2, and C-6; and H3-13/C-4, C-5, and C-6 (Fig. 2)
allowed us to assemble the aforementioned fragments to
corroborate the backbone of 1 to be 1,1,5-trimethyl-4-cyclo-
hexen-3-one. Additionally, one oxygenated butyl chain was
observed from the cross-peaks of H-6/H-7/H2-8/H-9/H3-10 in
the 1H–1H COSY spectrum and this butyl chain was attached to C-6
*
Corresponding author. Tel.: +86 21 20231968; fax: +86 21 20231968.
E-mail address: ljxuan@mail.shcnc.ac.cn (L.-j. Xuan).
These authors contributed equally to this work.
1
http://dx.doi.org/10.1016/j.phytol.2014.02.011
1874-3900/ß 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.

102
W.-b. Wei et al. / Phytochemistry Letters 8 (2014) 101–104
Fig. 1. Chemical structures of compounds 1–3.
based on the HMBC correlations from H-7 to C-6, C-1, and C-5. All
of this evidence suggested that compound 1 was a megastigmane
glycoside (Ninomiya et al., 2007). In addition, the glucose unit was
located at C-9, as supported by the HMBC correlation from the
The molecular formula of sarconepaside B (2) was established
to be C21H38O9 as indicated by the quasi molecular ion at m/z
457.2426 ([M+Na]+, calcd 457.2414). The IR absorption bands
showed the presence of hydroxy (3417 cmꢀ1) group. In the 13C
NMR and DEPT spectra, 21 carbon signals were observed, including
15 resonances attributed to a sesquiterpene skeleton and 6
resonances ascribable to a sugar unit. The 13C NMR spectrum of 2
clearly displayed four methyls (dC 23.1, dC 22.0, dC 21.7, and dC
anomeric proton at dH 4.55 to C-9 at d
C 78.3 (Fig. 2). Detailed 1H and
13C NMR assignment were shown (Table 1). The S configuration for
C-6 was determined by the negative Cotton effect at 219 nm
(
De219 = ꢀ1.80) in the CD spectrum (Pabst et al., 1992). And the
absolute configuration of C-9 was characterized as R by comparing
the chemical shift of C-9 ( C = 78.3) with the literature (Takeda
14.6), three methylenes (
C 47.8, C 41.4, and C 28.3, three oxygenated including
72.0, and C 71.9), and two quaternary carbon ( C 74.3 and
from the sesquiterpene. An eudesmane skeleton was established
d
C 39.5,
d
C 29.9, and
d
C 27.1), six methines
C 78.3, dC
C 44.5)
d
(
d
d
d
d
et al., 1997a,b). On the basis of the above-mentioned evidences, the
structure of compound 1 was established as shown.
d
d
d
Fig. 2. Key HMBC (H!C) and 1H–1H COSY (–) correlations of 1–3.
Table 1
1H NMR (400 MHz) and 13C NMR (100 MHz) data of 1 in CD3OD and 2 in D2O (
d
in ppm, J in Hz).
Position
1
2
dH
dC
dH
dC
1
2
37.8, C
3.89 m
72.0, CH
2.06 d (18.6)
2.73 d (18.6)
49.4, CH2
1.75 m
27.1, CH2
1.46 m
3
203.9, C
1.50 m, 1.76 m
39.5, CH2
74.3, C
4
6.14 s
129.4, CH
165.0, C
5
2.16 d (7.4)
4.62 dd (7.4, 3.1)
1.80 m
47.8, CH
78.3, CH
41.4, CH
29.9, CH2
71.9, CH
44.5, C
6
2.25 d (2.0)
4.68 m
58.8, CH
70.3, CH
46.5, CH2
78.3, CH
22.7, CH3
27.7, CH3
30.6, CH3
28.4, CH3
7
8
1.75 m, 1.93 m
4.08 m
2.04 m
9
3.70 m
10
11
12
13
14
15
10
20
30
40
50
60
1.35 d (6.0)
1.18 s
2.03 m
28.3, CH
22.0, CH3
21.7, CH3
14.6, CH3
23.1, CH3
100.9, CH
74.2, CH
76.1, CH
70.2, CH
76.1, CH
61.1, CH2
1.04 s
1.02 d (6.9)
2.17 s
0.97 d (6.9)
0.96 s
1.35 s
4.55 d (7.8)
104.6, CH
75.6, CH
78.6, CH
72.1, CH
78.3, CH
63.2, CH2
4.69 d (7.9)
3.27 dd (8.9, 7.8)
3.30 dd (8.7, 7.9)
3.50 dd (8.7, 8.5)
3.41 dd (8.5, 8.5)
3.40 ddd (8.5, 4.6, 2.5)
3.72 dd (12.1, 2.5), 3.92 dd (12.1, 4.6)
3.51 dd (9.1, 8.9)
3.39 dd (9.3, 9.1)
3.52 ddd (9.3, 6.0, 2.2)
3.91 dd (12.6, 2.2), 3.74 dd (12.6, 6.0)

W.-b. Wei et al. / Phytochemistry Letters 8 (2014) 101–104
103
Fig. 3. Key ROESY ($) correlations of 2 and 3.
Table 2
1H NMR (400 MHz) and 13C NMR (100 MHz) data of 3 in D2O (
d
in ppm, J in Hz).
Position
dH
dC
Position
dH
dC
1
1.95 m, 0.90 m
3.88 m
47.1, CH2
67.7, CH
75.9, CH
42.7, C
22
23
24
25
26
27
28
29
30
10
1.70 m, 1.82 m
3.53 m
1.03 s
31.1, CH2
63.3, CH2
13.4, CH3
17.1, CH3
16.9, CH3
23.4, CH3
178.4, C
2
3
3.36 m
4
1.33 s
5
1.32 m
46.8, CH
67.4, CH
38.5, CH2
37.7, C
0.94 s
6
4.43 brs
1.20 s
7
1.50 dd (15.2, 4.2), 1.68 m
8
0.94 s
26.7, CH3
23.3, CH3
93.5, CH
71.1, CH
74.8, CH
68.2, CH
75.3, CH
67.1, CH2
101.8, CH
72.5, CH
74.9, CH
68.9, CH
75.3, CH
60.0, CH2
9
1.87 m
46.8, CH
36.4, C
0.98 s
10
11
12
13
14
15
16
17
18
19
20
21
5.50 d (7.5)
2.07 m, 2.07 m
5.5 d (1.5)
22.6. CH2
124.2, CH
140.7, C
40.9, C
20
3.51 m
30
3.60 m
40
3.58 m
50
3.42 m
1.61 m, 1.06 m
2.17 m, 1.63 m
27.1, CH2
25.9, CH2
45.0, C
60
4.19 dd (12.1, 4.2), 3.92 dd (12.1, 2.6)
100
200
300
400
500
600
4.51 d (8.2)
3.29 dd (8.7, 8.2)
3.51 m
3.05 brs
3.37 brs
42.8, CH
80.1, CH
33.5, C
3.42 m
3.72 m
1.12 m, 1.69 m
26.8, CH2
3.88 m, 3.80 m
by not only the 1H–1H COSY spectrum (Fig. 2) but also the HMBC
correlations of H-1/C-10; H2-2/C-10; H-5/C-10 and C-14; H-9/C-
6; H3-14/C-1, C-9, and C-10; and H3-15/C-3, C-4, and C-5 (Fig. 2).
This deduction was further confirmed by comparing the NMR
H2-1/H-2/H-3; H-5/H-6/H2-7; H-9/H2-11/H-12; H2-15/H2-16; and
H2-21/H2-22 (Fig. 2) demonstrated their vicinal coupling systems.
Furthermore, detailed HMBC correlations (Fig. 2) indicated that
compound3wasanolean-12-enoleananetriterpene,whichshowed
great resemblance to the known aglycone combregenin after
comparing the NMR data with the literature (Jossang et al., 1996).
data with those of pumilaside A (Kitajima et al., 2000). In the 13
NMR spectrum, the chemical shifts of C-1 ( C 72.0), C-4 ( C 74.3),
C
d
d
and C-9 (dC 71.9), together with the 1H–1H COSY spectrum
indicated the presences of 1-OH, 4-OH, and 9-OH. This deduction
was supported by the HMBC spectrum. Hydrolysis of compound 2
By hydrolyzing 3,
Coupling constants of the anomeric protons H-10
J = 7.5 Hz) and H-100
dH 4.51, d, J = 8.2 Hz) indicated the
configurations for both sugar units. In the meanwhile, the HMBC
(Fig. 2) correlations from H-10 ( C 178.4) and H-100
H 5.50) to C-28 (
H 4.51) to C-60 (
C 67.1) specified the linkages of each sugar unit,
D-glucose was found to be the only sugar product.
(dH 5.50, d,
(
b
yielded
proton J = 7.9 Hz indicated the
linkage of the sugar unit to the aglycone was established by the
HMBC correlation from H-10 (
H 4.69, d, J = 7.9 Hz) to C-6 ( C 78.3)
D
-glucose and the large coupling constant of the anomeric
b
-configuration of the sugar. The
d
d
(d
d
d
d
respectively. The ROESY correlations of H-3/H2-23, H2-23/H-6, H-6/
H-5, H-5/H-9, and H-9/H3-27; H-2/H3-24, H-2/H3-25, H3-24/H3-25,
and H3-25/H3-26 confirmed the relative configuration of compound
3, same as combregenin (Fig. 3). Hence, the structure elucidation of
compound 3 was finalized.
(Fig. 2). Moreover, the relative configuration of 2 was established
by a ROESY spectrum (Fig. 3). Hence, the structure of 2 was
determined.
Sarconepaside C (3) exhibited a sodiated molecular ion at m/z
867.4343 (calcd 867.4354) in the HRESIMS analysis, supportive of a
molecular formula of C42H68O17 with 9 degrees of unsaturation. The
IR spectrum showed absorption bands of olefin (1647 cmꢀ1),
hydroxy (3404 cmꢀ1), and ester (1728, 1070 cmꢀ1) functionalities.
Analysis of the NMR data (Table 2) revealed 42 carbon signals
including 30 resonances assignable to a triterpene skeleton and 12
resonances attributable to two sugar units. The carbon signals of
the triterpene part were further classified using a DEPT experi-
ment as six methyls, eight methylenes (one oxygenated), eight
methines (one olefinic and three oxygenated), eight quaternary
3. Conclusion
One new megastigmane glycoside (1) and two new terpenic
glycosides (2 and 3) were isolated from the grass of S. nepalensis.
Their structures were identified by spectroscopic data and named
as sarconepasides A–C, respectively.
4. Experimental
carbons (one carbonyl,
d
C178.4). Two sugar units, one carbonyl,
4.1. General
and one double bond accounted for 4 degrees of unsaturation,
which suggested compound 3 was likely a pentacyclic triterpene
glycoside. In the 1H–1H COSY spectrum, the cross-peaks of
Reverse-phase column chromatography: Sephadex LH-20
(20–80
mm; Amersham Pharmacia Biotech AB), MCI CHP-20P

104
W.-b. Wei et al. / Phytochemistry Letters 8 (2014) 101–104
gel (75–150
m
m; Mitsubishi Chemical Industries Co. Ltd.), HW-
m; Tosoh Co. Ltd.), and Cosmosil 75 C18-OPN (20–
m; Nacalai Tesque Inc.). TLC: precoated silica-gel GF254
4.5. Physical and spectroscopic data of new compound
40F (30–60
45
m
m
;
4.5.1. Sarconepaside A (1)
visualization under UV light, with I2 vapor, or by spraying
anisaldehyde/sulfuric acid reagent. Optical rotation: Perkin-
Elmer 341 polarimeter. CD spectrum: JASCO J-810 instrument.
UV Spectra: Shimadazu UV-2450 spectrophotometer. IR Spectra:
Hitachi 275-50 spectrometer. 1H NMR, 13C NMR, and 2D NMR
(COSY, HMQC, HMBC, ROESY) spectra: Bruker DRX-400 spec-
trometer. ESIMS and HRESIMS: Finnigan LCQ-DECA spectrometer.
EIMS and HREIMS: Finnigan MAT-95 mass spectrometer.
White amorphous powder. a2D0 ¼ þ13 (c = 0.1, H2O). CD
(MeOH) lmax nm (De) 219 (ꢀ1.80), 321 (+0.67). UV (MeOH):
lmax nm (log e) 246 (3.65). IR (KBr): 3407, 2933, 2875, 1637,
1076 cmꢀ1. 1H and 13C NMR (CD3OD): see Table 1. ESIMS (pos.): m/
z 799 [2M+Na]+. ESIMS (neg.): m/z 433 [M+HCO2]ꢀ. HRESIMS: m/z
411.1994 ([M+Na]+, C19H32O8Na+; calcd 411.1995).
4.5.2. Sarconepaside B (2)
White amorphous powder. a2D0 ¼ ꢀ15 (c = 0.1, H2O). IR (KBr):
3417, 2931, 2871, 1078 cmꢀ1. 1H and 13C NMR (D2O): see Table 1.
ESIMS (pos.): m/z 457 [M+Na]+. ESIMS (neg.): m/z 479 [M+HCO2]ꢀ.
HRESIMS: m/z 457.2426 ([M+Na]+, C21H38O9Na+; calcd 457.2414).
4.2. Plant material
The grasses of S. nepalensis were collected from Sanming,
located in Fujian Province, PR China, in September 2008, and
4.5.3. Sarconepaside C (3)
authenticated by Prof. Heming Yang.
A voucher specimen
White amorphous powder. a2D0 ¼ ꢀ16 (c = 0.1, H2O). IR (KBr):
(No.SIMMSN01) was deposited at the Herbarium of Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, PR
China.
3403, 2931, 1727, 1646, 1070 cmꢀ1 1H and 13C NMR (D2O) see
.
Table 2. ESIMS (pos.): m/z 867 [M+Na]+; ESIMS (neg.): m/z 889
[M+HCO2]ꢀ. HRESIMS: m/z 867.4343 ([M+Na]+, C42H68O17Na+;
calcd 867.4354).
4.3. Extraction and isolation
References
Air-dried grasses (4.5 kg) were pulverized and extracted with
70% aqueous ethanol at r.t. (10 L, 3 ꢁ 24 h). Solvent was removed
under reduced pressure to obtain a crude extract (980 g), which
was suspended in H2O and partitioned with CHCl3, and n-BuOH.
The n-BuOH (100 g) fraction was subjected to HP20 CC and
eluted with H2O, 20%, 40%, 60%, 80%, and 100% MeOH gradiently
to give five fractions (Fr. A–Fr. F). Fr. C was subjected to CC (MCI;
MeOH/H2O 10–50%) to afford four fractions (I–IV). Fr. II was
subjected to CC (HW-40F; MeOH/H2O 1–10%) to yield com-
pounds 1 (12 mg) and 2 (10 mg). Fr. III was chromatographed on
a C18 column eluted with MeOH/H2O (5–60%), and further
separated over a C8 column using MeOH/H2O (5–75%) to afford
roseoside (7 mg). Fr. D (6.5 g) was subjected to MCI column
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Compounds 1–3 (5 mg each) were dissolved in H2O (5 mL),
and b-cellulase (20 mg) was added to the solution and incubated
at 37 8C for 2 days. The reaction mixtures were extracted with
EtOAc, and the aqueous phase was compared to an authentic
sugar sample by co-TLC (EtOAc–MeOH–H2O–HOAc, 13:3:3:4, Rf
0.46 for glucose). The identification of
layer was realized by comparing the optical rotation of the
liberated glucose with that of an authentic sample of -glucose
a2D0 ¼ þ52).
D-glucose in each aqueous
D
(