Two new dammarane monodesmosides from Centella asiatica

Article abstract of DOI:10.1080/10286020.2011.588212

Two new dammarane monodesmosides centellosides A (1) and B (2), and two new natural products ginsenosides Mc (10) and Y (11), together with 11 known compounds (3-9 and 12-15) reported for the first time from this genus, were isolated from the whole plants of Centella asiatica. All structures were elucidated by spectroscopic techniques and chemical methods, and compared with literature values. All the isolated compounds were evaluated in vitro for cytotoxicity.

Full text of DOI:10.1080/10286020.2011.588212

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Two new dammarane monodesmosides
from Centella asiatica
Xiao-Xiang Weng a , Yan Shao a , Yun-Yan Chen a , Wen Gao a ,
Liang Cheng a & De-Yun Kong a
a Department of Chinese Traditional Medicine, Shanghai Institute
of Pharmaceutical Industry, Shanghai, 200040, China
Published online: 13 Jul 2011.
To cite this article: Xiao-Xiang Weng , Yan Shao , Yun-Yan Chen , Wen Gao , Liang Cheng & De-Yun
Kong (2011): Two new dammarane monodesmosides from Centella asiatica , Journal of Asian Natural
Products Research, 13:8, 749-755
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Journal of Asian Natural Products Research
Vol. 13, No. 8, August 2011, 749–755
Two new dammarane monodesmosides from Centella asiatica
Xiao-Xiang Weng, Yan Shao, Yun-Yan Chen, Wen Gao, Liang Cheng and De-Yun Kong*
Department of Chinese Traditional Medicine, Shanghai Institute of Pharmaceutical Industry,
Shanghai 200040, China
(Received 16 March 2011; final version received 11 May 2011)
Two new dammarane monodesmosides centellosides A (1) and B (2), and two new
natural products ginsenosides Mc (10) and Y (11), together with 11 known compounds
(3–9 and 12–15) reported for the first time from this genus, were isolated from the
whole plants of Centella asiatica. All structures were elucidated by spectroscopic
techniques and chemical methods, and compared with literature values. All the isolated
compounds were evaluated in vitro for cytotoxicity.
Keywords: Centella asiatica; centelloside; ginsenoside; cytotoxicity
1. Introduction
These 13 known compounds were isolated
for the first time from this genus. Some of
the compounds exhibited mild inhibitory
activity against HepG2 (human hepatocel-
lular carcinoma), K562 (human chronic
myeloid leukemia), and BGC-823 (human
gastric carcinoma) cells.
Centella asiatica (L.) Urban (Apiaceae) is
a traditional herbal medicine used in
Asiatic countries. Experimental and clini-
cal investigations showed that it had a
wide spectrum of medicinal effects, e.g.
the use in the treatment of venous
insufficiency, striae gravidarum, and
wound-healing disturbances [1]. Previous
studies of this plant have resulted in the
isolation of more than 70 constituents,
which mainly contain pentacyclic triter-
penes [2,3]. Although no tetracyclic
triterpenoid saponin has been reported so
far, a dammarenediol synthase was iso-
lated and characterized from this plant [4].
This observation prompted us to discover
new tetracyclic triterpenes with potential
bioactivity. In the present research, two
new dammarane saponins named as
centelloside A (1) and centelloside B (2),
two new natural products named as
ginsenoside Mc (10) and ginsenoside Y
(11), and 11 further related known deri-
vatives (tetracyclic) were isolated from the
whole plant of C. asiatica (Figure 1).
2. Results and discussion
Compound 1 was obtained as a white
amorphous powder. Its HR–ESI–MS
showed a quasi-molecular ion peak
[M þ Na]þ at m/z 921.5194, in accord
with the molecular formula C47H78O16.
The IR spectrum showed absorption bands
at 3407 (OH) and 1638 (CvC) cm21. The
negative ESI–MS–MS of 1 exhibited
fragment ion peaks at m/z 765 ([M 2 H-
132(pentosyl)]2 and 603 ([M 2 H-132-
162(hexosyl)]2) suggesting the presence
of pentosyl and hexosyl units in 1 and a
pentosyl unit as the terminal sugar moiety.
The resonances for three anomeric meth-
ines at dH 4.81 (d, J ¼ 6.8 Hz)/dC 104.7,
dH 5.37 (d, J ¼ 7.6 Hz)/dC 103.2, and dH
5.24 (d, J ¼ 6.4 Hz)/dC 106.4 revealed the
*Corresponding author. Email: deyunk@yahoo.com.cn
ISSN 1028-6020 print/ISSN 1477-2213 online
q 2011 Taylor & Francis
DOI: 10.1080/10286020.2011.588212
http://www.informaworld.com

750
X.-X. Weng et al.
21
OH
12
24
26
22
20
17
21
OH
22
25
23
20
13
11
19
27
18
16
1
4
14
9
2
3
15
8
10
30
7
5
RO
6
RO
29
28
1
3
R = Xyl (1
R = Glc (1
2) Glc (1
2) Glc
2) Glc
2
4
R = Xyl (1 2) Glc (1
2) Glc
R = Glc (1
2) Glc
21
21
HO
OH
22
R2O
OH
22
20
20
RO
R1O
5
6
R = Xyl (1
R = Glc (1
2) Glc (1
2) Glc
2) Glc
7—15
Compounds
R1
R2
Glc
H
Glc
7
Glc(1→2)Glc
8
Xyl(1→2)Glc(1→2)Glc
H
9
H
Araf(1→6)Glc
Arap(1→6)Glc
Xyl(1→6)Glc
Araf(1→6)Glc
Arap(1→6)Glc
Xyl(1→6)Glc
10
11
12
13
14
15
H
H
Glc
Glc
Glc
Glc = β-D-glucopyranosyl, Xyl = β-D-xylopyranosyl, Araf = α-L-arabinofuranosyl,
Arap = α-L-arabinopyranosyl.
Figure 1. Chemical structures of compounds 1–15.
1
presence of three sugar moieties with
b-orientation. Comparative study of the
sugar resonances [5] indicated the exist-
ence of two b-glucopyranose units and one
b-xylopyranose unit. Further comparison
of the NMR spectral data of 1 with those of
3 indicated that 1 had one more xylopyr-
anosyl unit than 3 [6]. The structure was
further assigned by HMQC, HMBC,
TOCSY, and H–1H COSY experiments.
In the HMBC spectrum of 1, the location
and the sequence of sugar moieties were
demonstrated by the key correlations from
H-10 (d 4.81) to C-3 (d 89.0), H-100 (d 5.37)
to C-20 (d 82.9), and H-1000 (d 5.24) to C-200
(d 84.6). The HMBC correlations of H-11
and H-13 with C-12 (d 72.5) confirmed
that the hydroxy was linked at C-12. Other

Journal of Asian Natural Products Research
751
key HMBC and 1H–1H COSY corre-
lations are shown in Figure 2. From these
data, the structure of compound 1 was,
thus, determined as 3b,12b-dihydroxy-
dammar-20(21),24-diene 3-O-b-D-xylo-
pyranosyl-(1 ! 2)-O-b-D-glucopyrano-
syl-(1 ! 2)-O-b-D-glucopyranoside, and
named centelloside A.
Rg5, Rh3, and Rh4 [6], while the methyl
carbon of Z type was usually observed at
lower field around 30ppm [7]. Inthe HMBC
spectrum of 2, the long-range correlations
from H-10 (d 4.80) to C-3 (d 89.0), H-100 (d
5.36) to C-20 (d 82.9), and H-1000 (d 5.23) to
C-200 (d 84.6), proved the linkage sequence
of sugar units. The key HMBC and 1H–1H
COSY correlations for side chain at C-17
are shown in Figure 2. From the above
evidence, the structure of compound 2 was
elucidated as (20E)-3b,12b-dihydroxydam-
mar-20(22),24-diene 3-O-b-d-xylopyrano-
syl-(1 ! 2)-O-b-d-glucopyranosyl-(1 !
2)-O-b-d-glucopyranoside, and named cen-
telloside B.
Compound 2 was obtained as a white
amorphous powder. The HR–ESI–MS of 2
displayed a quasi-molecular ion peak at m/z
921.5191 [M þ Na]þ, in agreement with
the molecular formula C47H78O16. Its IR
spectrum showed absorption bands at 3422
(OH) and 1640 (CvC) cm21. Pentosyl and
hexosyl units in 2 and a pentosyl unit as
the terminal sugar moiety were deduced
from the characteristic fragment ion
peaks (negative ESI–MS–MS) at m/z
765 ([M 2 H-132(pentosyl)]2 and 603
([M 2 H-132-162(hexosyl)]2). The 1H
and 13C NMR spectral data (Table 1) of 2
wereverysimilartothose of4, exceptforthe
appearance of a set of additional signals in 2
ascribed to one xylopyranosyl unit [dH 5.23
(d, J ¼ 6.4 Hz)/dC 106.4]. The 13C NMR
spectral data (Table 1) of the sugar moieties
of 2 were in good agreement with those of 1.
The chemical shift of C-21 at d 13.1
indicated the presence of an E-type double
bond at C-20, as present in the ginsenosides
The other 13 known compounds were
identified as ginsenoside Rk1 (3) [6],
ginsenoside Rg5 (4) [8], (20R)-ginsenoside
Rg3 (5) [9], notoginsenoside Ft1 (6) [5],
ginsenoside F2 (7) [10,11], (20S)-ginseno-
side Rg3 (8) [9], notoginsenoside ST-4 (9)
[12], ginsenoside Mc (10) [13], ginseno-
side Y (11) [14], gypenoside ib (12) [15],
notoginsenoside Fe (13) [16], ginsenoside
Rd2 (14) [17,18], and gypenoside h (15)
[19] by comparison of their spectroscopic
data with those reported in the literature.
Ginsenosides Mc and Y are two new
natural products among them.
OH
HO
HO
HO
HO
HO
HO
O
O
17
O O
O
O
HO
HO
2
1
OH
HMBC
1H-1HCOSY
1
Figure 2. Selected HMBC and H–1H COSY correlations for 1 and 2.

752
X.-X. Weng et al.
Table 1. 1H NMR (400 MHz) and 13C NMR (100 MHz) spectral data of 1 and 2 (C5D5N).
1
2
Position
dC
dH
dC
dH
1
2
39.3 t
26.7 t
0.68 (m), 1.38 (m)
1.72 (br.d, 11.6), 2.08 (dd, 10.0, 3.6)
39.3 t
28.8 t
0.72 (m), 1.41 (m)
1.40 (m), 1.88 (m)
3
4
5
89.0 d 3.20 (dd, 11.6, 3.6)
39.8 s
56.5 d 0.63 (d, 11.6)
89.0 d 3.20 (dd, 11.6, 4.4)
40.3 s
56.5 d 0.62 (d, 11.2)
6
7
8
18.5 t
35.4 t
40.2 s
1.32 (m), 1.45(m)
1.43 (m), 1.19 (m)
18.5 t
35.4 t
39.8 s
1.37 (m), 1.47 (m)
1.17 (m), 1.40 (m)
9
50.8 d 1.32 (m)
37.1 s
50.8 d 1.31 (m)
37.1 s
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
10
32.6 t
1.32 (m), 1.81 (m)
32.2 t
1.35 (m), 1.84 (m)
72.5 d 3.80 (m)
52.5 d 1.97 (t, 10.8)
51.2 s
32.6 t
30.7 t
48.2 d 2.70 (m)
16.4 q 0.92 (s)
15.8 q 0.72 (s)
155.6 s
108.2 t
33.9 t
27.1 t
72.6 d 3.81 (m)
50.4 d 2.68 (t, 7.6)
50.9 s
32.6 t
26.7 t
51.1 d 1.89 (m)
16.4 q 0.72 (s)
16.6 q 1.00 (s)
140.2 s
13.1 q 1.71 (s)
123.6 d 5.40 (t, 7.2)
0.98 (m), 1.60 (m)
1.46 (m), 1.95 (m)
1.01 (m), 1.60 (m)
1.74 (m), 2.10 (m)
4.80 (m), 5.04 (br.s)
2.20 (m), 2.28 (m)
2.22 (m), 2.86 (t, 6.8)
27.4 t
123.8 d 5.13 (t, 7.2)
131.3 s
2.68 (t, 7.6)
125.3 d 5.20 (m)
131.2 s
25.7 q 1.57 (s)
17.7 q 1.51 (s)
28.1 q 1.19 (s)
16.6 q 1.01 (s)
17.0 q 0.86 (s)
104.7 d 4.81 (d, 6.8)
82.9 d 3.95 (m)
77.9 d 4.15 (m)
71.9 d 4.03 (m)
77.6 d 3.98 (m)
25.6 q 1.53 (s)
17.7 q 1.49 (s)
28.1 q 1.18 (s)
15.9 q 0.92 (s)
17.1 q 0.86 (s)
104.7 d 4.80 (d, 7.6)
82.9 d 3.95 (m)
77.9 d 3.99 (m)
71.9 d 4.03 (m)
77.6 d 4.15 (m)
20
30
40
500
600
100
200
300
400
500
6
63.0 t
4.13 (m), 4.34 (br.d, 10.4)
63.0 t
4.13 (m), 4.33 (br.d, 8.8)
103.2 d 5.37 (d, 7.6)
84.6 d 4.05 (m)
78.1 d 3.80 (m)
71.1 d 3.95 (m)
77.6 d 3.72 (m)
103.2 d 5.36 (d, 7.6)
84.6 d 4.05 (m)
78.1 d 3.78 (m)
71.2 d 4.00 (m)
77.6 d 3.73 (m)
63.0 t
4.21 (m), 4.41 (br.d, 11.6)
63.0 t
4.20 (m), 4.41 (br.d, 11.2)
1000
2000
3000
4000
5000
106.4 d 5.24 (d, 6.4)
75.8 d 3.96 (m)
78.6 d 4.19 (m)
70.7 d 3.96 (m)
106.4 d 5.23 (d, 6.4)
75.8 d 3.96 (m)
78.6 d 4.18 (m)
70.7 d 3.98 (m)
67.3 t
3.57 (t, 10.0), 4.23 (m)
67.3 t
3.56 (t, 9.6), 4.20 (m)

Journal of Asian Natural Products Research
753
Compounds 1, 3, 11, and 12 showed
mild in vitro cytotoxicity against HepG2
and K562 cells, with IC50 values in the
range of 19.93–54.59 mM.
The extracts were combined and concen-
trated to a certain volume (3 L), and then
95% EtOH (15 L) was added and allowed
to stand for 24 h. The precipitate was
removed by filtration. After solvent
removal of the filtrate to 3 L, the crude
extract was suspended in H2O and
extracted with BuOH for two times (6
and 4.8 L). The BuOH extracts (165 g)
were subjected to silica gel column
chromatography (200–300 mesh, 1.1 kg,
8.5 £ 43 cm) using gradient elution with
3. Experimental
3.1 General experimental procedures
Optical rotations were measured on a
Perkin-Elmer 341 polarimeter (San Jose,
CA, USA). IR spectra were recorded in KBr
pellets on a Nicolet-NEXUS-670-FTIR
spectrophotometer (Madison, WI, USA).
NMR spectra were determined on a Varian
INOVA-400 instrument (Palo Alto, CA,
USA). HR–ESI–MS and ESI–MS/MS
spectra were recorded on a Waters Q-TOF
micro YA019 mass spectrometer (Leeder-
ville, WA, USA). Preparative HPLC was
performed on a Shimadzu HPLC system
(LC-8Apump, SPD-M10Adetector; Kyoto,
Japan) with a Shimadzu PRC-ODS column
(15 m, i.d. 20 £ 250 mm; Kyoto, Japan).
Analytical GC was carried out on an Agilent
6890N system (H2 flame ionization detec-
tor; Minneapolis, MN, USA) and a capillary
a
mixture of CHCl2 –MeOH–H2O
(10:2:0.2, 10:4:0.4, 10:5:0.6, 10:6:1, and
100%EtOH, each 6 L) to give fractions 1–
12. Fraction 3 (2.0 g) was further purified
by preparative HPLC [MeOH–H2O
(90:10, 6 ml/min, 204 nm)] to yield frac-
tions A3–E3. Fraction C3 (86 mg) was
further applied to preparative HPLC [CH3
CN–H2O (48:52, 6 ml/min, 204 nm)] to
afford 10 (55 mg, tR: 42 min). Fraction D3
(188 mg) was subjected to preparative
HPLC [CH3CN–H2O (44:56, 6 ml/min,
204 nm)] to obtain 11 (47 mg, tR: 87 min)
and 12 (120 mg, tR: 96 min). From fraction
E3 (180 mg), 3 (56 mg, tR: 78 min) and 4
(50 mg, tR: 86 min) were obtained by
preparative HPLC [MeOH–H2O (82:18,
6 ml/min, 204 nm)]. Fraction 4 (3.2 g) was
separated by Sephadex LH-20 (35 g,
2.5 £ 44 cm, MeOH) and then further
purified by preparative HPLC [MeOH–
H2O (83:17, 6 ml/min, 204 nm)] to give
fractions A4–E4. Fraction C4 (312 mg) was
subjected to preparative HPLC [CH3CN–
H2O (50:50, 6 ml/min, 204 nm)] to provide
6 (55 mg, tR: 33 min), 7 (77 mg, tR:
20 min), and 8 (107 mg, tR: 30 min).
Fraction D4 (143 mg) was separated over
preparative HPLC [CH3CN–H2O (53:47,
6 ml/min, 204 nm)] to yield 1 (15 mg, tR:
37 min) and 2 (35 mg, tR: 44 min).
Similarly, fraction 5 (1.5 g) was submitted
to preparative HPLC [MeOH–H2O
(83:17, 6 ml/min, 204 nm)] to give frac-
tions A5–F5. Then, 13 (104 mg, tR: 45 min)
was obtained from fraction D5 (138 mg)
by preparative HPLC [CH3CN–H2O
column
(30 m £ 0.32 mm £ 0.25 mm;
Abel AB-5; Appleton, WI, USA). Materials
for column chromatography were silica gel
(200–300 mesh; Shanghai Sanpont Co.,
Shanghai, China) and Sephadex LH-20
(40–150 mm; Amersham Pharmacia Bio-
tech, Uppsala, Sweden).
3.2 Plant material
The whole plant materials of C. asiatica
were collected at Guangxi Zhuang Auton-
omous Region, China, in July 2008 and
identified by Dr Tong Wu of Shanghai
Institute of Pharmaceutical Industry.
A voucher specimen (SIPITCM-080711)
has been deposited at the institute.
3.3 Extraction and isolation
The air-dried whole plants of C. asiatica
(10 kg) were extracted with water two
times (100 L £ 1.5 h and 80 L £ 1 h).

754
X.-X. Weng et al.
(40:60, 6 ml/min, 204 nm)]. Fraction E5
(132 mg) was purified by preparative
HPLC [CH3CN–H2O (37:63, 6 ml/min,
204 nm)] to provide 14 (24 mg, tR: 83 min)
and 15 (56 mg, tR: 94 min). From fraction
F5 (134 mg), 5 (33 mg, tR: 55 min) and 9
(80 mg, tR: 52 min) were isolated using
preparative HPLC [CH3CN–H2O (42:58,
6 ml/min, 204 nm)].
2508C; injection volume: 2.0 ml; split ratio:
1:20; carrier gas: N2 at 1 ml/min. D-glucose
(tR: 14.442 min)/D-xylose (tR: 11.728 min)
were detected from 1 and 2 (identical to
authentic materials).
Acknowledgement
This work was financially sponsored by the
National Science and Technology Funding
‘Created a Significant New Drug,’ China
(Grant No. 2009ZX09301-007).
3.3.1 Centelloside A (1)
24
White amorphous powder. ½aꢀD þ 1.5 (c
0.66, MeOH); IR (KBr) nmax: 3407, 2930,
1638, 1454, 1389, 1174, 1077, 1043, 894,
618 cm21; 1H and 13C NMR spectral data,
see Table 1; ESI–MS (positive): m/z
921.30 [M þ Na]þ; ESI–MS (negative):
m/z 897.46 [M 2 H]2; HR–ESI–MS
(positive): m/z 921.5194 [M þ Na]þ (cal-
culated for C47H78 O16Na, 921.5188).
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3.3.2 Centelloside B (2)
24
White amorphous powder. ½aꢀD þ 1.8 (c
1.10, MeOH); IR (KBr) nmax: 3422, 2945,
1640, 1454, 1389, 1077, 1043, 895, 617
cm21; 1H and 13C NMR spectral data, see
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3.4 Acid hydrolysis of 1 and 2
Compounds 1 and 2 (5 mg each) were
refluxed in 2M HCl (2 ml) for 3 h. The
mixture was neutralized with NH4OH and
then partitioned with CHCl3. To the dried
aqueous layer, pyridine and acetic anhy-
dride (1 ml each) were added, and the
mixture was kept overnight. The acetyl-
ated derivatives were subjected to GC
analysis to identify the sugars. Conditions
for GC were: cap. column: AB-5 (30 m £
0.32 mm £ 0.25 mm); column temp.:
1008C/2508C; programmed increase:
108C/min; injector and detector temp.:

Journal of Asian Natural Products Research
755
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