Two new phenylpropanoid glycosides from Sanguisorba officinalis

Article abstract of DOI:10.1016/j.cclet.2012.08.001

Two new phenylpropanoid glycosides, 9-O-[6-O-acetyl-β-d- glucopyranosyl]-4-hydroxycinnamic acid (1) and 8-O-β-d-glucopyranosyl-(R)- (+)-3,4,8-trihydroxy methyl phenylpropionate (2) were isolated from the 80% EtOH extract of the roots of Sanguisorba offici

Full text of DOI:10.1016/j.cclet.2012.08.001

Available online at www.sciencedirect.com
Chinese Chemical Letters 23 (2012) 1243–1246
www.elsevier.com/locate/cclet
Two new phenylpropanoid glycosides from Sanguisorba officinalis
*
Jiang Hu , Xiao Dong Shi, Xia Mao, Wei Dong Lu, Lei Zhu, Long Yu
College of Biological Resources and Environment Science, Qujing Normal University, Qujing 655011, China
Received 17 May 2012
Abstract
Two new phenylpropanoid glycosides, 9-O-[6-O-acetyl-b-D-glucopyranosyl]-4-hydroxycinnamic acid (1) and 8-O-b-D-gluco-
pyranosyl-(R)-(+)-3,4,8-trihydroxy methyl phenylpropionate (2) were isolated from the 80% EtOH extract of the roots of
Sanguisorba officinalis. Their structures were characterized by spectroscopic analysis and chemical method, including 1D
NMR, 2D NMR, and HR-ESI-MS. Compounds 1 and 2 exhibited the moderate antimicrobial activities against all Gram-positive
and Gram-negative bacteria tested.
# 2012 Jiang Hu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords: Sanguisorba officinalis; Rosaceae; Phenylpropanoid glycosides; NMR techniques
Sanguisorba officinalis L. (Rosaceae), a perennial plant, distributes widely in northern districts of China [1]. 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 [2,3]. Previous studies reported the isolation of
triterpenoids, triterpenoid glycosides, and a series of hydrolysable tannins which were reported as characteristic
constituents of S. officinalis and are considered to be partially responsible for the therapeutic effects of this herbal drug
[4–6]. The chemical investigate of the 80% EtOH extract of the dry fronds of S. officinalis had led to the isolation of
two new phenylpropanoid glycosides (Fig. 1). This paper deals with the isolation and structural elucidation of the new
compounds on the basis of extensive 1D and 2D NMR (COSY, HMQC, HMBC, and NOESY) analyses. Furthermore,
the two new phenylpropanoid glycosides were in vitro evaluated for their antimicrobial activities against two Gram-
positive and three Gram-negative bacteria.
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 (X. Mao). A voucher specimen (20101001) is deposited in the Herbarium
of the College of Biological Resources and Environment Science, Qujing Normal University, Qujing, Yunnan
Province, China.
The roots (5 kg) of S. officinalis were extracted with 80% EtOH (10 L ꢀ3). After removal of EtOH under reduced
pressure, the aqueous brownish syrup (1 L) was partitioned with AcOEt to afford AcOEt extract (42 g). AcOEt soluble
extract was subjected to chromatography over SiO2 column, eluting with gradient CHCl3/MeOH to afford fractions
1–8. Fraction 5 (9.0 g) was chromatographed on a MCI gel column eluted with MeOH/H2O (from 60% to 95%) to
* Corresponding author.
E-mail address: hujiang@ustc.edu (J. Hu).
1001-8417/$ – see front matter # 2012 Jiang Hu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
http://dx.doi.org/10.1016/j.cclet.2012.08.001

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J. Hu et al. / Chinese Chemical Letters 23 (2012) 1243–1246
Fig. 1. Structures of compounds 1 and 2.
yield 3 subfractions, 5A–5C. Subfraction 5B (1.6 g) was separated by repeated column chromatography (CC) over
Sephadex LH-20 (MeOH), silica gel, and then preparative HPLC (MeOH/H2O 40% to 70%), yielding 1 (27.1 mg) and
2 (29.7 mg).
Compound 1 was obtained as a white amorphous solid. Its molecular formula was established as C17H20O9 with
8 degrees of unsaturation by HRESIMS (m/z 367.1025 [MꢁH]ꢁ, calcd. for C17H19O9, 367.1029). The 13C NMR
(125 MHz, CD3OD) data of 1 (Table 1) displayed the presence of one carboxyl group [dC 166.6 (s)], one Ac group
[dC 172.2 (s) and 20.4 (q)], and eight olefinic carbons arising from a phenyl and a disubstituted double bond [dC
145.9, 115.0 (d, each 1H)]. The 1H NMR (600 MHz, CD3OD) spectrum showed four aromatic protons at dH 7.60
(d, 2H, J = 8.2 Hz), 6.95 (d, 2H, J = 8.2 Hz) arising from a 1,4-disubstituted benzene ring, two olefinic protons at
dH 7.65 (d, 1H, J = 16.0 Hz) and 6.30 (d, 1H, J = 16.0 Hz) for a disubstituted trans double bond. These
spectroscopic data indicated the characteristic signals of one phenylpropanoid glycoside. The sugar moiety was
identified as a b-glucopyranosyl unit by the coupling constant of the anomeric proton [dH 4.32 (d, 1H, J = 8.0, glc
H-10)] and similarity of their NMR data with literature data (Table 1) [7]. The HMBC between the anomeric
proton of the glucopyranosyl unit and C-9 (dC 166.6) of the aglycone (Fig. 2). The C-60 location of the AcO group
Table 1
1H and 13C NMR data of compounds 1 and 2 (1H: 600 MHz; 13C: 125 MHz, in CD3OD).
1
2
3
dC
dH (mult., J in Hz)
dC
dH (mult., J in Hz)
dC
dH (mult., J in Hz)
1
2
3
4
5
6
7
127.0 (s)
116.7 (d)
131.2 (d)
160.3 (s)
131.2 (d)
116.7 (d)
145.9 (d)
–
129.8 (s)
118.3 (d)
147.2 (s)
145.8 (s)
117.2 (d)
122.8 (d)
39.0 (t)
–
130.2 (s)
117.9 (d)
146.5 (s)
145.5 (s)
116.7 (d)
122.4 (d)
41.5 (t)
–
7.60 (d, 8.2)
6. 95 (d, 8.2)
–
6.72 (d, 2.5)
6.69 (d, 2.5)
–
–
–
–
6. 95 (d, 8.2)
7.60 (d, 8.2)
7.65 (d, 16.0)
6. 68 (d, 8.2)
6.57 (dd, 8.2, 2.5)
2.82, 2.94
(dd, 12.6,7.8)
3.88 (d, 7.8)
–
6. 66 (d, 8.2)
6.55 (dd, 8.2, 2.5)
2.81, 2.93
(dd, 12.6, 7.8)
4.26 (d, 7.8)
–
8
115.0 (d)
166.6 (s)
6.30 (d, 16.0)
–
77.2 (d)
73.7 (d)
9
176.6 (s)
176.3 (s)
O-glc
10
20
30
40
50
60
106.8 (d)
75.8 (d)
78.1 (d)
73.0 (d)
75.2 (d)
64.8 (t)
4.32 (d, 8.0)
3.20 (m)
103.9 (d)
74.2 (d)
76.9 (d)
70.6 (d)
77.0 (d)
61.9 (t)
4.28 (d, 8.0)
3.17 (m)
3.38 (m)
3.40 (m)
3.28 (m)
3.28 (m)
3.38 (m)
3.36 (m)
4.26 (dd, 13.0, 6.6)
4.31 (dd, 13.0, 6.6)
–
3.82 (dd, 13.0, 7.0)
3.62 (dd, 13.0, 7.0)
3.68 (s)
OMe
–
52.7 (q)
52.5 (q)
3.69 (s)
C
O
172.2 (s)
20.4 (q)
–
–
–
–
Me
2.02 (s)
–

J. Hu et al. / Chinese Chemical Letters 23 (2012) 1243–1246
1245
Fig. 2. Key HMBC correlations of compounds 1 and 2.
Table 2
Antimicrobial and antifungal activities (zones of inhibition/and MIC mmol/L, n = 3) of compounds 1–14.
S. aureus
S. epidermidis
E. coli
K. pneumoniae
S. dysenteriae
1
16/2.02
17/2.31
21/0.003
15/2.24
15/1.99
25/0.003
17/1.97
16/2.47
24/0.008
16/2.84
17/2.90
25/0.006
15/2.54
15/2.01
23/0.010
2
Netilmicin
in the glucopyranosyl unit was confirmed by HMBC of H-60 (dH 4.31 and 4.26) with the CO C-atom (dC 172.2) of
the AcO group. Accordingly, the structure of 1 was established as 9-O-[6-O-acetyl-b-D-glucopyranosyl]-4-
hydroxycinnamic acid.
Compound 2 was obtained as a white amorphous powder. The HR-ESI-MS displayed a quasi-molecular ion peak
at m/z 373.1133 [MꢁH]ꢁ (calcd. for C16H21O10, 373.1135) corresponding to a molecular formula C16H22O10 for 2.
The 13C NMR and DEPT spectra (125 MHz, CD3OD) of 2 showed resonances characteristic of one phenylpropanoid,
one hexosyl unit, and one OMe group (Table 1). The 1H NMR spectrum (600 MHz, CD3OD) of 2 showed resonances
for a set of ABX-type signals [dH 6.72 (d, 1H, J = 2.5 Hz, H-2), 6.68 (d, 1H, J = 8.2 Hz, H-5), 6.57 (dd, 1H, J = 8.2,
2.5 Hz, H-6)], indicating a 1,3,4-trisubstituted benzene ring. In addition, one oxygenated methane coupled with one
methylene proton [dH 2.82 and 2.94 (dd, each 1H, J = 12.6, 7.8 Hz), H-7] appeared at dH 3.88 for H-8. Acid hydrolysis
of 2 with 1 mol/L HCl in dioxane–H2O (1:1) gave 2a and D-glucose as the carbohydrate components. The NMR data
23:3
(Table 1) and optical rotation f½aꢂD þ 6:1 (c = 0.46, MeOH)} of 2a are in good agreement with those of (R)-(+)-
3,4,8-trihydroxymethyl phenylpropionate (C10H12O5) reported in the literature [8]. The sugar moiety was identified
as a b-glucopyranosyl unit by the coupling constant of the anomeric proton [dH 4.28 (d, J = 8.0, glc H-10)] and its
NMR data (Table 1) [7]. The b-glucopyranosyl unit was positioned at C-8, and the methoxyl at C-9 respectively,
based on the HMBC correlations of the anomeric proton signal of sugar moiety with C-8, and of the methoxyl signal
(dH 3.88) with C-9 (Fig. 2). Consequently, compound 2 was unambiguously determined as 8-O-b-D-glucopyranosyl-
(R)-(+)-3,4,8-trihydroxymethylphenylpropionate.
Compounds 1 and 2 were tested for their antimicrobial activities against two Gram-positive bacteria:
Staphylococcus aureus and Staphylococcus epidermidis and three Gram-negative bacteria: Escherichia coli,
Klebsiella pneumoniae, and Shigella dysenteriae. Antimicrobial activities was evaluated by the disc diffusion
method by measuring the zone of inhibitions and the minimum inhibitory concentration (MIC) values were also
determined [9]. Standard antibiotic netilmicin was used in order to control the sensitivity of the tested bacteria. The
results (Table 2) showed that 1 and 2 exhibited moderate antimicrobial activities, with MIC value of 1.97–2.84 mmol/
L and 1.99–2.90 mmol/L respectively.
Acknowledgment
The above research was made possible by a grant from the Key Projects in Scientific Research of Qujing Normal
University (No. 2011ZD003).

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J. Hu et al. / Chinese Chemical Letters 23 (2012) 1243–1246
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