Two new rhamnopyranosides of neolignans from Sanguisorba officinalis

Article abstract of DOI:10.1080/10286020.2011.634803

Two new rhamnopyranosides of neolignans, (7S,8R)-4,9,5,9-tetrahydroxy-3,3- dimethoxy-8-O-4-neolignan-7-O-l-rhamnopyranoside (1) and (7S,8R)-4,9,9- trihydroxy-3,3,5-trimethoxy-8-O-4-neolignan-7-O-l-rhamnopyranoside (2), together with a known compound (7S,8R)-4,7,9,9-tetrahydroxy-3,3-dimethoxy-8-O-4- neolignan (3), were isolated from the 80% EtOH extract of the roots of Sanguisorba officinalis. Their structures were characterized by spectroscopic analysis including 1D NMR, 2D NMR, and HR-ESI-MS, and chemical method.

Full text of DOI:10.1080/10286020.2011.634803

Journal of Asian Natural Products Research
Vol. 14, No. 2, February 2012, 171–175
Two new rhamnopyranosides of neolignans from Sanguisorba
officinalis
Jiang Hu*, Xiao-Dong Shi*, Jian-Gang Chen and Chang-Sheng Li
College of Biological Resources and Environment Science, Qujing Normal University, Qujing
655011, China
(Received 1 September 2011; final version received 19 October 2011)
Two new rhamnopyranosides of neolignans, (7S,8R)-4,9,50,90-tetrahydroxy-3,30-
dimethoxy-8-O-40-neolignan-7-O-a-L-rhamnopyranoside (1) and (7S,8R)-4,9,90-trihy-
droxy-3,30,50-trimethoxy-8-O-40-neolignan-7-O-a-L-rhamnopyranoside (2), together
with a known compound (7S,8R)-4,7,9,90-tetrahydroxy-3,30-dimethoxy-8-O-40-neo-
lignan (3), were isolated from the 80% EtOH extract of the roots of Sanguisorba
officinalis. Their structures were characterized by spectroscopic analysis including 1D
NMR, 2D NMR, and HR-ESI-MS, and chemical method.
Keywords: Sanguisorba officinalis; Rosaceae; neolignans
1. Introduction
(7S,8R)-4,9,90-trihydroxy-3,30,50-trimeth-
oxy-8-O-40-neolignan-7-O-a-L-rhamno-
pyranoside (2), together with a known
compound (7S,8R)-4,7,9,90-tetrahydroxy-
3,30-dimethoxy-8-O-40-neolignan (3),
have been obtained (Figure 1). This
paper deals with the isolation and struc-
tural elucidation of the new compounds by
spectroscopic analysis and chemical
method.
Sanguisorba officinalis L. (Rosaceae), a
perennial plant, distributes widely in the
northern districts of China [1]. Its roots
have traditionally valuable hemostatic,
analgesic, and astringent properties [2].
In China, Korea, and Japan, this plant
has been used for the treatment of
inflammatory and metabolic disease such
as diarrhea, chronic intestinal infections,
duodenal ulcers, and bleeding [3]. Pre-
vious studies reported the isolation of
triterpenoids, triterpenoid glycosides, and
a series of hydrolysable tannins which
were reported as characteristic constitu-
ents of S. officinalis and are considered
to be partially responsible for the thera-
peutic effects of this herbal drug [4–6].
In our investigation on the components
of this titled plant, two new rhamnopyr-
anosides of neolignans, (7S,8R)-4,9,50,90-
tetrahydroxy-3,30-dimethoxy-8-O-40-neo-
lignan-7-O-a-L-rhamnopyranoside (1) and
2. Results and discussion
The CHCl3-soluble fraction of the 80%
EtOH extract of S. officinalis was purified
by repeated column chromatography (CC)
to afford compounds 1–3.
Compound 1 was obtained as a white
amorphous powder. Its molecular formula
was determined as C26H36O12 by HR-ESI-
MS at m/z 539.2129 [M 2 H]2, posses-
1
sing nine degrees of unsaturation. The H
and 13C NMR spectra of 1 showed
characteristic resonances for a neolignan
*Corresponding authors. Email: hujiang@ustc.edu; slf6121606@sina.com
ISSN 1028-6020 print/ISSN 1477-2213 online
q 2012 Taylor & Francis
http://dx.doi.org/10.1080/10286020.2011.634803
http://www.tandfonline.com

172
J. Hu et al.
6'
5
2
HO
4
3
HO
7S
R
O
8'
HO
OH
HO
6
1
5'
1'
9'
7'
OH
9
4'
2'
8R
MeO
MeO
O
3'
O
OMe
OH
OMe
5''
6''
4''
1''
2''
O
3''
HO
HO
OH
1 R = OH
2 R = Me
3
Figure 1. The structures of compounds 1–3.
moiety and a hexose moiety (Table 1).
Acidic hydrolysis of 1 with 2% HCl
afforded L-rhamnose, which was identified
by GC analysis of its trimethylsilyl
imidazole derivative [7,8]. The 13C NMR
signals of C-300 (dC 71.9) and C-500 (dC
69.1) indicated the a-configurations of
L-rhamnose unit (Table 1) [9].
1
Comparison of its H and 13C NMR
spectral data of the aglycone of 1 with those
of the known compound 3, obtained from
the same source, revealed that 1 and 3
Table 1. 1H and 13C NMR spectral data of compounds 1 and 2 (1H: 600 MHz; 13C: 125 MHz, in
CD3OD).
dH (J in Hz)
dC
Position
1
2
1
2
1
2
3
4
5
6
7
8
–
7.06 (d, 1.8)
–
7.07 (d, 1.8)
–
134.2, s
111.3, d
147.9, s
146.5, s
115.2, d
120.5, d
73.9, t
134.4, s
111.6, d
147.7, s
146.8, s
115.5, d
120.6, d
73.9, t
–
–
6.72 (d, 8.0)
–
6.75 (d, 8.0)
6.83 (dd, 1.8, 8.0)
4.85 (d, 5.1)
4.20 (m)
3.33 (t, 4.8)
–
6.80 (dd, 1.8, 8.0)
4.82 (d, 5.1)
4.18 (m)
3.30 (t, 4.8)
–
87.0, t
61.7, t
87.1, t
61.9, t
9
10
138.0, s
115.0, d
152.5, s
138.6, s
145.5, d
107.6, d
32.0, t
137.4, s
104.6, d
151.9, s
136.8, s
149.2, s
106.1, d
32.2, t
20
6.24 (d, 1.8)
–
6.31 (d, 1.8)
–
30
40
–
–
–
–
50
60
6.12 (d, 1.8)
2.55 (t, 4.8)
1.80 (m)
3.59 (t, 4.8)
4.83 (d, 1.3)
3.67 (m)
3.30 (m)
3.30 (m)
3.75 (m)
1.18 (d, 6.0)
3.82 (s)
6.20 (d, 1.8)
2.59 (t, 4.8)
1.82 (m)
3.61(t, 4.8)
4.80 (d, 1.3)
3.65 (m)
3.27 (m)
3.32 (m)
3.73 (m)
1.22 (d, 6.0)
3.83 (s)
70
800
32.6, t
67.0, t
32.7, t
66.7, t
900
100
90.8, d
72.5, d
71.9, d
73.7, d
69.1, d
18.5, d
56.1, q
56.2, q
91.3, d
72.7, d
72.0, d
73.9, d
69.3, d
18.8, d
56.3, q
56.5, q
54.9, q
2
300
400
500
600
OCH3
OCH3
OCH3
3.78 (s)
–
3.80 (s)
3.73 (s)

Journal of Asian Natural Products Research
173
possessed a similar skeleton [10]. The
difference between them laid in the down-
field shift of C-7 by 7.2 ppm and of C-50 by
25.7 ppm, suggesting that the rhamnose
unit and a hydroxy group were substituted
at C-7 and C-50, respectively. The structural
feature was further confirmed by the
HMBC correlation between the anomeric
proton (dH 4.83, d, J ¼ 1.3 Hz) of the
hexose unit and C-7 (dC 73.9) of the
aglycone (Figure 2). The small coupling
between H-8/H-2 and H-8/H-6 were
observed. The CD spectrum of 2 also
showed a negative Cotton effect at
240 nm (D1 22.36). On the basis of the
above evidence, the absolute configu-
ration was determined to be 7S,8R [11].
Thus, the structure of 2 was established
and named as (7S,8R)-4,9,90-trihydroxy-
3,30,50-trimethoxy-8-O-40-neolignan-7-O-
a-L-rhamnopyranoside.
1
constant (J7,8 ¼ 5.1 Hz) in the H NMR
3. Experimental
spectrum indicated a erythro configuration
between H-7 and H-8. The negative Cotton
effect at 240 nm (D1 22.54), together with
the clear NOESY correlations between
H-8/H-2 and H-8/H-6 indicated the
7S,8R-configuration in 1 [11]. Thus, the
structure of 1 is defined as (7S,8R)-
4,9,50,90-tetrahydroxy-3,30-dimethoxy-8-
O-40-neolignan-7-O-a-L-rhamnopyrano-
side.
3.1 General experimental procedures
Melting points were determined on a XT-4
microscopic thermometer without correc-
tion. Optical rotations were measured on a
Perkin-Elmer 341 polarimeter. IR spectra
were recorded on a Nicolet Magna FT-IR
750 spectrophotometer using KBr disks.
NMR spectra were recorded on Bruker
AM-300, Bruker AM-400, and Varian
Inova NMR spectrometers. The chemical
shift (d) values are given in ppm with TMS
as internal standard, and coupling con-
stants (J) are in Hz. FAB-MS and HR-ESI-
MS spectra were recorded on a VG
AutoSpec-3000 mass spectrometer. Col-
umn chromatographic separations were
carried out using silica gel (200–300 mesh
and H60, Qingdao Haiyang Chemical
Group Corporation, Qingdao, China),
MCI gel CHP20P (75–150 mm, Mitsu-
bishi Chemical Industries, Tokyo, Japan),
and Sephadex LH-20 (Pharmacia Biotech
AB, Uppsala, Sweden) as packing
material. TLC was carried out on
Compound 2 was isolated as a white
amorphous powder. Its molecular formula
was determined as C27H38O12 by HR-ESI-
MS at m/z 553.2283 [M 2 H]2. Inspection
of its NMR spectral data revealed that 2
possessed a neolignan moiety and a hexose
moiety (Table 1). Comparison of the 13C
NMR spectrum of 2 with that of 1 (Table 1)
indicated the presence of one more
methoxyl in compound 2, which was linked
to C-50 by the HMBC correlation between
OCH3 (dH 3.73, s) and C-50 (dC 149.2;
Figure 2). Similarly, a small coupling
1
constant (J7,8 ¼ 5.1 Hz) in the H NMR
spectrum and clear NOE correlations
OHMeO
H
HO
OH HO
H
HO
OH
OH
MeO
O
MeO
O
H
H
O
O
OMe
OMe
O
O
HO
HO
HO
HO
OH
OH
Figure 2. Key HMBC ({) correlations of compounds 1 and 2.

174
J. Hu et al.
precoated silica gel GF254 plates (Yantai
Chemical Industries, Yantai, China), and
the TLC spots were viewed at 254 nm and
visualized using 5% sulfuric acid in
alcohol containing 10 mg/ml of vanillin.
Analytical HPLC was carried out on a
Waters 2690 instrument with a 996
photodiode array detector (PAD) coupled
with an Alltech ELSD 2000 detector.
Semipreparative and preparative HPLC
were carry out on a Varian SD1 instrument
with a 320 single-wave detector. Their
chromatographic separations were carried
out on C-18 columns (250 £ 10 mm, 5 mm,
Waters; 220 £ 25 mm, 10 mm, respect-
ively, Merck, Darmstadt, Germany),
using a gradient solvent system compris-
ing H2O and MeCN, with a flow rate of 3.0
and 15.0 ml/min, respectively.
(A) (5.3 g) were permeated through Sepha-
dex LH-20 using a MeOH–CH3Cl (1:1)
system to give 30 subfractions A1–A30.
Fractions A10–A15 (214 mg) were further
purified with silica gel chromatography
eluted with CH3Cl–MeOH (95:5 ! 1:1) to
afford 3 (33 mg). Fractions F41–F55
(3.2 g) were further purified by repeated
CC over Sephadex LH-20 (CHCl3–MeOH,
1:1, and MeOH), silica gel chromatography
eluted with CHCl3–MeOH (8:2) and then
preparative HPLC (MeOH–H2O, from
50% to 75%), to obtain 1 (22 mg;
23.35 min) and 2 (29 mg; 24.60 min).
3.3.1 (7S,8R)-4,9,50,90-Tetrahydroxy-
3,30-dimethoxy-8-O-40-neolignan-7-O-a-
L-rhamnopyranoside (1)
A white amorphous powder; C26H36O12;
22
m.p. 188–1908C; ½aꢀD 266.48 (c 0.26,
3.2 Plant material
MeOH); UV (MeOH) lmax (log 1) 204
(4.05), 279 (3.66) nm; CD (MeOH):
D1240 nm 22.54; IR (KBr) nmax 3420,
The dried roots of S. officinalis were
collected in the suburb of Qujing, Yunnan
Province of China, in October 2010 and
identified by one of the authors (J.G.
Chen). A voucher specimen (20101001)
has been deposited in the Herbarium of the
College of Biological Resources and
Environment Science, Qujing Normal
University, Qujing, Yunnan Province,
China.
1605, 1515 cm21
;
1H and 13C NMR
spectral data: see Table 1; FAB-MS
(neg.): m/z 539 [M 2 H]2; HR-ESI-MS
(neg.): m/z 539.2126 [M 2 H]2 (calcu-
lated for C26H35O12, 539.2129).
3.3.2 (7S,8R)-4,9,90-Trihydroxy-3,30,50-
trimethoxy-8-O-40-neolignan-7-O-a-L-
rhamnopyranoside (2)
3.3 Extraction and isolation
A white amorphous powder; C27H38O12;
22
The roots (5 kg) of S. officinalis were cut
into small pieces and ground, and then
extracted with 80% EtOH (10 liters £ 3).
After removal of EtOH under reduced
pressure, the aqueous brownish syrup
(2 liters) was partitioned successively with
petroleum ether, CHCl3, and EtOAc.
Concentration of the solvent afforded
petroleum ether extract (51 g), CHCl3
extract (81 g), and EtOAc extract (143 g).
The CHCl3 extract (81 g) was chromato-
graphed over silica gel column, eluting
with a CHCl3–MeOH gradient to afford 80
fractions (F1–F80). Fractions F17–F25
m.p. 197–1998C; ½aꢀD 273.55 (c 0.41,
MeOH); UV (MeOH) lmax (log 1) 205
(5.01), 280 (4.23) nm; CD (MeOH): D1
240 nm 22.36; IR (KBr) nmax 3418, 1595,
;
1511 cm21 1H and 13C NMR spectral
data: see Table 1; FAB-MS (neg.): m/z 553
[M 2 H]2; HR-ESI-MS (neg.): m/z
553.2283 [M 2 H]2 (calculated for
C27H37O12, 553.2285).
3.4 Sugaranalysis of compounds1and2
The solutions of those sugar parts obtained
as described above in pyridine (2 ml) were

Journal of Asian Natural Products Research
added to L-cysteine methyl ester hydro- References
175
chloride (1.5 mg) and were kept at 608C for
1 h each. Then, trimethylsilyl imidazole
(1.5 ml) was added to the reaction mixture
and kept at 608C for 30 min. The super-
natant was subjected to GC analysis under
the following conditions: column tempera-
ture: 180/2808C, programed increase:
38C/min, carrier gas: N2 (1 ml/min), injec-
tor and detector temperature: 2508C,
injection volume: 4 mL, split ratio: 1/50.
Configuration identification of L-rhamnose
was carried out by comparing with its
derivative’s retention time [7,8]. Retention
times in GC of standard L/D-rhamnose
derivatives were 15.849/16.312 min. By
comparing with the retention time of the
authentic sugars in the form of derivatives
under the same condition, the sugar
moieties of compounds 1 and 2 were
determined to be L-rhamnose. All chemical
reagents and standard sugars were pur-
chased from Sigma-Aldrich Corporation
(St Louis, MI, USA).
[1] D.L. Chen and X.P. Cao, Phytochemistry
31, 1317 (1992).
[2] J. East, J. Ethnopharmacol. 12, 273(1955).
[3] T. Yu, Y.J. Lee, H.M. Yang, S. Han,
J.H. Kim, Y. Lee, C. Kim, M.H. Han,
M.Y. Kim, J. Lee, and J.Y. Cho,
J. Ethnopharmacol. 134, 11 (2011).
[4] X. Liu, B.F. Shi, and B. Yu, Tetrahedron
60, 11647 (2004).
[5] Y. Mimaki, M. Fukushima, A. Yokosuka,
Y. Sashida, S. Furuya, and H. Sakagami,
Phytochemistry 57, 773 (2001).
[6] X. Liu, Y. Cui, Q. Yu, and B. Yu,
Phytochemistry 66, 1671 (2005).
[7] S. Hara, H. Okabe, and K. Mihashi, Chem.
Pharm. Bull. 35, 501 (1987).
[8] J.F. Xu, Z.M. Feng, J. Liu, and P.C.
Zhang, Chem. Biodiv. 5, 591 (2008).
[9] P.K. Agrawal, Phytochemistry 31, 3307
(1992).
[10] N. Matsuda and M. Kikuchi, Chem.
Pharm. Bull. 44, 1676 (1996).
[11] M.L. Gan, Y.L. Zhang, S. Lin, M.T. Liu,
W.X. Song, J.C. Zi, Y.C. Yang, X.N. Fan,
J.G. Shi, J.F. Hu, J.D. Sun, and N.H.
Chen, J. Nat. Prod. 71, 647 (2008).

Copyright of Journal of Asian Natural Products Research is the property of Taylor & Francis Ltd and its content
may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express
written permission. However, users may print, download, or email articles for individual use.