Two new dammarane-type triterpenoids from the stems and leaves of Panax notoginseng

Article abstract of DOI:10.1080/10286020.2020.1731801

Two new dammarane-type triterpenoids, notoginsenoside SY1 (1) and notoginsenoside SY2 (2), were isolated from the stems and leaves of Panax notoginseng. Their structures were elucidated to be 3β, 12β-dihydroxy-22, 23, 24, 25, 26, 27-hexanordammarane-20-on

Full text of DOI:10.1080/10286020.2020.1731801

Journal of Asian Natural Products Research
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Two new dammarane-type triterpenoids from the
stems and leaves of Panax notoginseng
Chong-Kang Yang, Jiao Xiong & Yong Shen
To cite this article: Chong-Kang Yang, Jiao Xiong & Yong Shen (2020): Two new dammarane-
type triterpenoids from the stems and leaves of Panaxꢀnotoginseng, Journal of Asian Natural
Products Research, DOI: 10.1080/10286020.2020.1731801
To link to this article: https://doi.org/10.1080/10286020.2020.1731801
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JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
https://doi.org/10.1080/10286020.2020.1731801
Two new dammarane-type triterpenoids from the stems
and leaves of Panax notoginseng
Chong-Kang Yanga,b,c, Jiao Xionga,b,c and Yong Shena,b,c
aCollege of Agriculture and Biotechnology, Yunnan Agricultural University, Kunming 650201, China;
bResearch & Development center for Functional products, Yunnan Agricultural University, Kunming
c
650201, China; Kunming Kangren Biotechnology CO., Ltd, Kunming 650033, China
ABSTRACT
ARTICLE HISTORY
Received 18 November 2019
Accepted 16 February 2020
Two new dammarane-type triterpenoids, notoginsenoside SY1 (1)
and notoginsenoside SY2 (2), were isolated from the stems and
leaves of Panax notoginseng. Their structures were elucidated
to be 3b, 12b-dihydroxy-22, 23, 24, 25, 26, 27-hexanordammarane-
20-one 3-O-b-D-xylopyranosyl-(1!2)-O-b-D-glucopyranosyl-(1!2)-O-
b-D-glucopyranoside (1), 3b, 12b-dihydroxy-20S, 24R-epoxydammar-
25-ene 3-O-b-D-xylopyranosyl-(1!2)-O-b-D-glucopyranosyl-(1!2)-O-
b-D-glucopyranoside (2) by IR, HRESIMS and NMR experiments.
KEYWORDS
Panax notoginseng;
dammarane-type
triterpenes; notoginsenoside
SY1; notoginsenoside SY2
1. Introduction
Panax notoginseng (Burk.) F. H. Chen, a traditional Chinese medicine known as
“Sanqi” in Chinese, is mainly distributed in Yunnan and Guangxi Provinces in China
[1]. The stems and leaves of P. notoginseng were traditionally used to treat bone frac-
tures, eliminate swelling, and stop bleeding [2]. Previous phytochemical investigations
on the stems and leaves of this plant revealed that protopanaxadiol type saponins,
such as ginsenosides Rb1, Rc, Rb2, and Rb3, were the primary constituents, which had
been found to possess some beneficial pharmacological effects with anti-oxidative,
antihyperlipidemic and hepatoprotective activities [3–6]. Their total saponins and gin-
senoside Rb1 are clinically employed for the treatment of various insomnia and for-
getfulness in China [7]. To find more biologically active substances, the stems and
leaves of P. notoginseng were phytochemically investigated to afford two new
CONTACT Jiao Xiong
543499252@qq.com; Yong Shen
pharmsy@sina.com
College of Agriculture and
Biotechnology, Yunnan Agricultural University, Kunming 650201, China
ß 2020 Informa UK Limited, trading as Taylor & Francis Group

2
C.-K. YANG ET AL.
saponins, notoginsenoside SY1 (1) and notoginsenoside SY2 (2) (Figure 1). This
paper described their isolation and structural elucidation.
2. Results and discussion
Compound 1 was obtained as a white amorphous powder, and its molecular formula
was assigned as C41H68O17 based on the HRESIMS ion peak at m/z 855.4348
[M þ Na]þ. The IR spectrum showed absorption bands for hydroxyl (3413 cmꢀ1) and
carbonyl (1697 cmꢀ1) groups. Compound 1 revealed the presence of 41 resonances in
the 13C NMR (DEPT) spectrum (Table 1) attributing to six methyls, ten methylenes,
twenty methines and five quaternary C-atoms, including three anomeric carbons (dC
103.2, 105.2, and 106.6) of sugar moieties and one carbonyl carbon (dC 217.1). The
1H NMR spectrum data (Table 1) of 1 displayed six singlet methyls [dH 0.86, 0.90,
0.92, 1.05, 1.06, and 2.22 (each 3 H, s)] and three anomeric protons at dH 4.42 (1 H,
d, J ¼ 7.5 Hz, H-10), 4.78 (d, J ¼ 7.7 Hz, H-100), 4.52 (d, J ¼ 7.4 Hz, H-1000). The large
coupling constants of the anomeric protons were compatible with the b-configuration
for three sugar moieties [8], which were determined to be D configurations based on
1
acidic hydrolysis experiment. The H and 13C NMR spectral data (Table 1) of com-
pound 1 were identical to those of ginsenoside R10 [9], except that 1 was shown to pos-
sess one more glucopyranosyl and xylopyranosyl units in sugar chain. In the HMBC
spectrum of 1, the long-range correlations between dH 4.42 (H-10) and dC 91.5 (C-3),
dH 4.78 (H-100) and dC 81.5 (C-20), dH 4.52 (H-1000) and dC 85.1 (C-200) revealed the
Figure 1. Structures of compounds 1 and 2.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
3
Table 1. 1H and 13C NMR (500 MHz, 125 MHz in MeOD) spectral data for compounds 1 and 2.
1
2
Position
dC
dH
1.04-1.06 m, 1.73
dC
dH
1.00-1.04 m, 1.70
ꢁ
ꢁ
1
2
3
4
5
6
7
8
40.4
27.3
91.5
40.7
57.5
19.3
36.4
41.1
52.0
38.1
32.9
72.5
54.7
52.5
33.6
28.5
53.6
16.2
16.7
217.1
30.4
40.3
27.2
91.5
40.7
57.6
19.3
35.9
41.0
51.5
37.9
29.4
71.8
51.1
53.1
33.3
27.1
50.0
16.0
16.7
87.5
27.2
32.2
30.1
82.1
144.8
113.5
19.1
28.2
16.9
18.3
ꢁ
ꢁ
ꢁ
ꢁ
1.75 , 1.98
1.72 , 1.98
3.20-3.23 m
3.18-3.20 m
0.79 d (11.6)
0.80 d (11.7)
1.28-1.30 m, 1.50
1.33-1.36 m, 1.51
ꢁ
ꢁ
ꢁ
ꢁ
1.49 , 1.57
ꢁ
ꢁ
1.29-1.32 m, 1.49
ꢁ
ꢁ
9
1.47
1.48
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
3-O-Glc
10
ꢁ
ꢁ
1.46 , 1.79
1.36-1.38 m, 1.86
ꢁ
ꢁ
3.50
2.08
3.46
1.65
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
1.19-1.23 m, 1.58
1.60-1.62 m, 2.05
2.91 td (10.7, 5.8)
1.05 s
0.86 s
1.10-1.12 m, 1.59
1.16-1.19 m, 1.98
ꢁ
2.18
1.01 s
0.86 s
2.22 s
1.30 s
ꢁ
ꢁ
1.74 , 1.88
ꢁ
1.77 , 2.11-2.13 m
4.44 d (7.4)
4.87 s, 4.97 s
1.78 s
1.06 s
0.91 s
0.92 s
28.3
17.0
17.2
1.06 s
0.90 s
0.92 s
105.2
81.5
78.0
70.8
77.2
63.3
4.42 d (7.5)
105.2
81.5
78.0
71.9
77.2
63.3
4.43 d (7.5)
20
3.52
3.28
3.52
3.26
3.49
3.25
3.28
3.29
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
30
40
50
60
3.65 dd (11.8, 5.3), 3.84
3.64 dd (12.0, 5.3), 3.82
ꢁ
ꢁ
Glc
1"
2"
3"
4"
5"
6"
Xyl
1"’
2"’
30"
40"
50"
103.2
85.1
78.2
71.0
77.7
62.9
4.78 d (7.7)
103.1
85.1
78.2
71.0
77.7
62.8
4.78 d (7.7)
ꢁ
ꢁ
3.37
3.28
3.31
3.55
3.34
3.26
3.33
3.53
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
3.58 , 3.84
3.56 , 3.82
106.6
75.8
78.5
70.8
67.3
4.52 d (7.4)
106.6
75.8
78.5
70.8
67.3
4.52 d (7.5)
ꢁ
ꢁ
3.28
3.53
3.52
3.25
3.50
3.53
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
3.25 , 3.97 dd (11.5, 5.3)
3.23 , 3.95 dd (11.5, 5.3)
ꢁ
Overlapped.
linkage sequence of sugar units (Figure 2). The a-orientation of H-17 was demonstrated
by the ROESY correlations between H-17 (dH 2.91, 1 H, td, J ¼ 10.7, 5.8 Hz) and
H-30 (dH 0.91, 3 H, s) (Figure 2). Other key 2 D NMR correlations confirmed the
structure of 1 as shown in Figure 2. Therefore, the structure of compound 1 was
characterized as 3b, 12b-dihydroxy-22, 23, 24, 25, 26, 27-hexanordammarane-20-one

4
C.-K. YANG ET AL.
3-O-b-D-xylopyranosyl-(1!2)-O-b-D-glucopyranosyl-(1!2)-O-b-D-glucopyranoside,
named notoginsenoside SY1.
Compound 2 was isolated as a white amorphous powder. The molecular formula
was determined to be C47H78O17 based on the m/z 937.5131 [M þ Na]þ. The IR spec-
trum displayed strong absorption bands at 3418 and 1637 cmꢀ1 due to hydroxyl and
olefinic carbonyl functional groups. In the 13C NMR (DEPT) spectrum, compound 2
exhibited 47 resonances, bearing 7 methyls, 13 methylenes, 21 methines, and 6 qua-
ternary C-atoms. The signals at dC 144.8 and 113.5 in the 13C NMR spectrum showed
1
the existence of two olefinic carbons. In the H NMR spectrum (Table 1), seven sing-
let methyls [dH 0.86, 0.91, 0.92, 1.01, 1.06, 1.30, 1.78 (each 3 H, s)], a pair of olefinic
protons [dH 4.87 (1 H, s) and dH 4.97 (1 H, s)], and three anomeric protons signals
[(dH 4.43 (d, J ¼ 7.5 Hz), 4.78 (d, J ¼ 7.7 Hz), 4.52 (d, J ¼ 7.5 Hz)] were observed. The
glucose and the xylose were determined to be b configuration via the coupling
constants of their anomeric protons [8]. Acid hydrolysis of compound 2 provided D-
1
glucose and D-xylose by GC. The H and 13C NMR spectra (Table 1) of compound 2
were identical with those of compound 1 except for the signals caused by the side
chain part (C-20–C-27) in 2, which were similar to those of 3b,6a,12b-trihydroxy-
20S, 24 R-epoxydammar-25-ene [10]. This speculation was further confirmed by the
following key HMBC correlations: from dH 2.18 (H-17) to dC 87.5 (C-20), from dH
1.30 (H-21) to dC 50.0 (C-17), dC 87.5 (C-20) and dC 32.2 (C-22), from dH 4.97
(H-26) to dC 82.1 (C-24) and dC 144.8 (C-25), and from dH 1.78 (H-27) to dC 82.1
(C-24), dC 144.8 (C-25) and dC 113.5 (C-26) (Figure 2). H-24 and CH3-21 were
Figure 2. Key HMBC and ROESY correlations of compounds 1 and 2.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
5
elucidated to be a-oriented based on the ROESY correlations between H-24 (dH 4.44)
and CH3-21 (dH 1.30), CH3-21 and H-17 (dH 2.18, a-orientation) (Figure 2). From
the above data, the structure of compound 2 was established to be 3b, 12b-dihydroxy-20S,
24 R-epoxydammar-25-ene 3-O-b-D-xylopyranosyl-(1!2)-O-b-D-glucopyranosyl-
(1!2)-O-b-D-glucopyranoside, named notoginsenoside SY2.
3. Experimental
3.1. General experimental procedures
Optical rotations were determined on a Jasco model 1020 polarimeter (Horiba,
Tokyo, Japan). IR (KBr discs, cmꢀ1) spectra were recorded on a Bio-Rad FTS-135
spectrometer (Bio-Rad, Hercules, CA). 1 D and 2 D NMR were recorded on Bruker
DRX-500 (Bruker, Bremerhaven, Germany). High resolution electrospray ionization
mass spectrum (HRESIMS) were run on a VG Spec3000 spectrometer (VG,
Manchester, UK) and Waters AutoSpec Premier P776 (Waters, Milford, MA). D101
macroreticular resin (Tianjin Haiguang Chemical Co., Ltd, Haiguang, Tianjing,
China), silica gel (200–300 mesh, Qingdao Makall Chemical Company, Makall,
Qingdao, China), and RP C18 silica gel (300–400 mesh, Merck KGaA, Merck,
Darmstadt, Germany) were used in the open column chromatography. Gas chroma-
tography (GC) was performed on the Agilent technologies 6890 N apparatus (Agilent,
Santa Clara, USA). TLC was carried on the GF254 plates (Makall, Qingdao, China).
Analytical-grade reagents of chloroform (CHCl3), ethanol (EtOH), and methanol
(MeOH) were purchased from Kemiou Pure Chemical Co. Ltd. (Kemiou Tianjin,
China). Fractions were visualized by silica gel plates sprayed with 10% H2SO4 ethanol
solution followed by heating.
3.2. Plant material
The air-dried stems and leaves of Panax notoginseng (Burk.) F. H. Chen were col-
lected from WenShan County, Yunnan province, China, in August 2015, and authen-
ticated by Prof. Qing-Er Yang from South China Botanical Garden, Chinese Academy
of Sciences. The voucher specimen (No. YAU 2015-8-1) has been deposited in the
College of Agriculture and Biotechnology, Yunnan Agricultural University.
3.3. Extraction and isolation
The air-dried stems and leaves of P. notoginseng (5 kg) were extracted with 70%
EtOH for three times (1.5 h ꢂ 3) under reflux. After removal of the ethanol under
reduced pressure, the ethanolic extract was subjected to D101 resin column, eluting
with H2O and 90% EtOH, successively. The EtOH eluent was combined and concen-
trated under reduced pressure to give the total saponin fraction (416 g), which was
subjected to column chromatography (CC) on silica gel (2 kg, 200 ꢀ 300 mesh) eluted
with a gradient CHCl3-MeOH-H2O (9:1:0.1!6.5:3.5:0.5) to provide five fractions
(Frs.A ꢀ E). Fr.C (8 g) was carried out on silica gel CC (CHCl3-MeOH-H2O,
8.5:1.5:0.15) to give five fractions (Frs.C1 ꢀ C5). Fr.C3 (2.3 g) was repeatedly

6
C.-K. YANG ET AL.
chromatographed over silica gel (CHCl3-MeOH-H2O, 8.5:1.5:0.15), Rp-18 columns
(MeOH-H2O, 8:2) to yield 1 (16 mg). Fr.D (12 g) was subjected to a silica gel column
and eluted with CHCl3-MeOH-H2O (8:2:0.2) to afford six fractions (Frs.D1 ꢀ D6).
Fr.D2 (2.7 g) was applied to silica gel CC with an eluent of CHCl3-MeOH-H2O
(8:2:0.2), and further purified through Rp-18 columns (MeOH-H2O, 8.5:2.5) to obtain
2 (18 mg).
3.3.1. Notoginsenoside SY1 (1)
White amorphous powder; Libermann-Burchard and Molish reactions were positive;
22
½aꢃD þ10.34 (c 0.16, MeOH); IRꢀmax 3413, 2943, 2879, 1697, 1631, 1389, 1360, 1173,
1
1075, 1044, and 895 cmꢀ1; H NMR (500 MHz, MeOD) and 13C NMR (125 MHz,
MeOD) spectral data are shown in Table 1; HRESIMS: m/z 855.4348 [M þ Na]þ
(calcd for C41H68O17Na, 855.4349).
3.3.2. Notoginsenoside SY2 (2)
White amorphous powder; Libermann-Burchard and Molish reactions were positive;
22
½aꢃD ꢀ1.75 (c 0.22, MeOH); IRꢀmax 3418, 2967, 2945, 2878, 1720, 1637, 1453, 1388,
1200, 1077, 1045, and 896 cmꢀ1 1H NMR (500 MHz, MeOD) and 13C NMR
;
(125 MHz, MeOD) spectral data are shown in Table 1; HRESIMS: m/z 93s7.5131
[M þ Na]þ (calcd for C47H78O17Na, 937.5131).
3.4. Acid hydrolysis
The acid hydrolysis of new compounds and sugar determination were based on Gu’s
method by GC analysis [11]. Compounds 1 and 2 (each 5 mg) were hydrolyzed in
2 M HCl (5 ml) at 65 ꢄC for 6 h, respectively. The reaction mixture was extracted with
CHCl3 three times (3 ꢂ 5 ml). The aqueous layer was neutralized with 2 M NaOH and
dried to produce a monosaccharide mixture. Then, a solution of the sugar mixture in
pyridine (2 ml) was added to L-cysteine methyl ester hydrochloride (1.5 mg) and kept
at 60 ꢄC for 1 h. After this, trimethylsilylimidazole (1.5 ml) was added to the reaction
mixture in an ice ꢀ water bath and kept at 60 ꢄC for 30 min. The mixture was sub-
jected to GC analysis, run on an Agilent 6890 N gas chromatograph, equipped with a
30 m ꢂ 0.32 mm HP-5 column and a H2 flame ionization detector with the following
conditions: column temperature, 200 ꢀ 260 ꢄC; programmed increase, 10 ꢄC/min; car-
rier gas, N2 (1 ml/min); injector and detector temperature, 260 ꢄC; injection volume,
1 ll; and split ratio 1/50. The retention times for the authentic samples (Sigma), after
being treated in the similar manner, were 19.82 min (D-glucose) and 14.12 min (D-
xylose). The peaks of the hydrolysate of two compounds were detected at tR 19.82
and 14.12 min for D-glucose and D-xylose, respectively.
Acknowledgments
The authors are grateful to the staff of analytical group at the State Key Laboratory of
Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese
Academy of Sciences for the spectral data.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
7
Disclosure statement
No potential conflict of interest was reported by the authors.
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