Two new monoterpenes and one dicaffeic acid ester from Sibiraea angustata with hypolipidemic activities in HepG2 cells in Vitro

Article abstract of DOI:10.1016/j.phytol.2015.07.009

Two new monoterpenes, named sibiscolacton B (1) and sibiscolacton C (2), together with a sorbate obtained from the natural product 1, 6-sorbitol-O-dicaffeic acid ester (3), were isolated from an aqueous extract of the aerial portion of Sibiraea angustata. The compounds' structures were elucidated on the basis of extensive spectroscopic analysis, as well as literature comparisons. A preliminary in vitro bioassay showed that all of the compounds exhibited hypolipidemic effects in HepG2 cells.

Full text of DOI:10.1016/j.phytol.2015.07.009

Phytochemistry Letters 13 (2015) 319–323
Contents lists available at ScienceDirect
Phytochemistry Letters
journal homepage: www.elsevier.com/locate/phytol
Short communication
Two new monoterpenes and one dicaffeic acid ester from Sibiraea
angustata with hypolipidemic activities in HepG2 cells in Vitro
a,
a
a
a,b
a
c
Bin Li *, Xiaotian Chen , Zhangwei Wang , Hongdong Liu , Bo Liu , Shishan Yu ,
a
a
d
Xuewen Lai , Xianghong Xu , Toshimitsu Hayashi
Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China
Jiangzhong Pharmaceutical Group Company Limited, Nanchang 330096, China
State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and
Peking Union Medical College, Beijing 100050, China
a
b
c
d
Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, Toyama 930-0194, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Two new monoterpenes, named sibiscolacton B (1) and sibiscolacton C (2), together with a sorbate
obtained from the natural product 1, 6-sorbitol-O-dicaffeic acid ester (3), were isolated from an aqueous
extract of the aerial portion of Sibiraea angustata. The compounds’ structures were elucidated on the basis
of extensive spectroscopic analysis, as well as literature comparisons. A preliminary in vitro bioassay
showed that all of the compounds exhibited hypolipidemic effects in HepG2 cells.
Received 5 May 2015
Received in revised form 24 June 2015
Accepted 6 July 2015
Available online xxx
ã 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
Keywords:
Sibiraea angustata
Sibiscolactone B
Sibiscolactone C
1,6-Sorbitol-O-dicaffeic acid ester
Hypolipidemic effect
1. Introduction
presented, demonstrating that all of the compounds exhibited an
effect in the in vitro bioassay.
Sibiraea angustata is a shrub of the Rosaceae family and is
widely distributed in the western part of China. The aerial part of
the plant is called “Liucha”, which is typically used to treat
indigestion and obesity in Tibetan folk medicine of China (Institute
of Botany, 1985). Thus, thorough chemical and bioactive studies
have been performed on this plant, leading to the identification of
one monoterpene glycoside (Ito et al., 2009), two monoterpenes (Li
et al., 2010) and eight monoterpene acylglucosides (Wang et al.,
2. Results and discussion
The ethanol extract of the powder residue from the aqueous
extract of S. angustata was concentrated under reduced pressure to
yield a solid brown material, which was applied to a Diaion HP-
2
20 chromatography column and eluted gradiently with EtOH/H O.
Fortunately, by following modern column chromatography, two
new monoterpenes, sibiscolactone B (1) and sibiscolactone C (2),
were isolated from the 95% EtOH fraction, and a natural product,
1,6-sorbitol-O-dicaffeic acid ester (3), was obtained from the 50%
EtOH fraction.
2
013) from the plant. In the current investigation, two new
monoterpenes named sibiscolacton B and sibiscolacton C(1–2)
Fig. 1) along with 1,6-sorbitol-O-C acid ester (3) (He et al., 2013)
(
were isolated from this plant. Compound 3 was obtained from
natural products even though it has been synthesized previously.
The structural elucidation was based on extensive two dimensional
NMR and High resolution ESI–MS spectra as well as literature
2
5
Compound 1 was obtained as a white powder with a ½
a
ꢀ
value
D
of ꢁ21.5 (CHCl
3
), the molecular formula of which was determined
from the molecular ion peak at m/z 184.1112 [M]+
to be C10H O
16 3
comparisons. In addition,
a preliminary evaluation of the
(
calc’d for 184.1100) in the HR–EI–MS. The IR spectrum also
hypolipidemic activities of these compounds in HepG2 cells was
ꢁ1
showed characteristic absorption bands for OH (3424 cm ) and
ꢁ
1
1
13
lactone (1726 cm ). The H NMR, C NMR and HSQC spectra of 1
Table 1) exhibited signals attributed to two vinyl methyls at
.73 ( 25.7) and 1.70 ( 18.5); one olefinic methine signal with a
proton at 5.19 (H-7) and a carbon at
oxygenated methylene group with protons at
(
d
H
1
d
C
d
C
d
H
d
d
C
125.1 (C-7); an
H
3.90, 3.69 (H-1)
*
Corresponding author. Fax: +86 791 87118825.
E-mail address: lbin@jzjt.com (B. Li).
http://dx.doi.org/10.1016/j.phytol.2015.07.009
874-3900/ã 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
1

3
20
B. Li et al. / Phytochemistry Letters 13 (2015) 319–323
HO
HO
3
2
O
7
1
''
CH2
1
9
4
8
O
H
HO
H
2
''
6
5
OH
H
3''
4''
O
OH
9
7
5
9
O
7
5
5''
H C
6
4
H C
4
H
OH
5
'
6'
3
3
3
6
8
7'
9'
O
3
1'
O
1
4'
CH
8
2
HO
HO
O
6
''
HO
H
8'
2
1
HO
O
H C
H C
2
2'
3
3
3'
1
0
10
Fig. 1. Structures of compounds 1–3.
Table 1
NMR spectral data of compound 1 (CDCl
a
3
, 400 MHz, 100 MHz) and 2 (CDCl
3
H
, 500 MHz, 125 MHz) [d mult . J (Hz)].
No.
1
2
1H
13C
71.2
HMBC
2, 3, 4
COSY
2
1H
13C
HMBC
2, 3, 4
COSY
1
3.90 ddd(12.0, 8.4,3.6)
4.80 d(1.5)
70.5
2
3
.69 m
2
3
4
5
1.96 m, 1.89 m
2.91 m
26.9
36.7
179.7
32.5
1, 3, 4
2, 4, 5
1, 3
2, 5
7.44 dd(2.0, 1.0)
148.8
128.9
174.5
33.5
1, 3, 4
1
2.00 m, 1.69 m
2, 3, 4, 6, 7
3, 6
2.36 ddd (14.5, 7.5, 1.5)
.22 ddd (14.5, 7.5, 1.5)
2, 4, 6, 7
6
2
6
7
8
9
4.29 ddd(8.8, 8.0, 2.2)
5.19 dd(6.4, 1.6)
64.3
125.1
136.5
25.7
7, 8
5, 9, 10
7, 5
5
4.40 m
5.10 dd(8.5, 1.5)
65.2
128.8
132.2
25.5
3, 8
5, 9, 10
7, 5
6
1.73 d(1.2)
1.70 d(1.2)
7, 8, 10
7, 8, 9
1.63 d (1.0)
1.56 d (1.0)
7, 8, 10
7, 8, 9
10
18.5
18.0
a
Multiplicity: s, singlet; d, doublet; t, triplet; dd, double doublet; m, multiplet.
and carbon at
d
C
71.2 (C-1); an oxygenated methenyl with signals at
4.29 (H-6) and 64.3 (C-6); two methylenes with signals at
.00, 1.69 (H-5), 32.5(C-5), and 1.96, 1.89 (H-2), 26.9 (C-2);
2.91 (H-3) and 36.7 (C-3).
136.5 (C-8) and a carbonyl carbon at
the above carbons. These spectroscopic features along with two
sp2 carbon signals (one double bond) at 136.5 (C-8) and 125.1
C
d 179.7 (C-4) in addition to
d
H
d
C
d
H
2
d
C
d
H
d
C
d
C
d
C
1
3
13
1
1
and a methenyl with signals at
d
H
d
C
C
(C-7) in the C NMR spectrum and the H– H COSY correlations
NMR and DEPT spectra showed an olefinic quaternary carbon at
d
C
(H-1/H-2; H-2/H-1, -3; H-3/H-2, -5; H-5/H-3, -6; H-6/H-5, -7; and
H
H
H
O
H
O
H
H C
3
H C
3
O
O
H C
HO
3
H C
H
H
3
HO
H
HO
HO
H
O
CH2
O
H
H
HO
H
OH
H
OH
H
H
OH
CH2
HO
HO
O
O
H
Fig. 2. Key HMBC (!), COSY (—) and NOE ($) correlations observed for compounds 1–3.

B. Li et al. / Phytochemistry Letters 13 (2015) 319–323
321
Table 2
H-7/H-6) suggested that compound 1 is a oxygenated geraniol-
NMR spectral data 0f compound 3 (CD
Sibirate.
3
OD, 400 MHz, 100 MHz) and compound
Sibirate
monoterpene with a carboxy monocyclic skeleton. The HMBC
spectrum (Fig. 2) showed key long-range correlations between the
following proton and carbon signals: H-1 and C-2, C-3, C-4; H-2 and
C-1, C-3,C-4;H-3andC-2,C-4,C-5;H-5andC-2,C-3,C-4,C-6,C-7;H-
No.
3
a
13
a
13
dH mult
. J (Hz)
C
dH mult
. J (Hz)
C
6
and C-7, C-8; and H-7 and C-5, C-9, C-10 as shown in Fig. 1.
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
127.8
115.1
146.8
149.6
115.2
123.0
147.2
116.5
169.5
127.7
115.0
146.8
149.5
115.2
122.9
147.1
116.5
169.2
67.3
126.8
112.0
146.6
150.0
115.3
121.1
144.5
114.1
166.4
Furthermore, two methyl singlets (H-9 and H-10) showed correla-
tionstotheolefiniccarbonsignalsatC-8andC-7,indicatingtwovinyl
methyls were connected to C-8. The coupling constant of 8.0 Hz
between the two protons of H-6 and H-7 suggests that the protons
occupied the same side, which was further confirmed by the
appearance of a signal between H-6 and H-7 in the NOSEY spectrum.
ThepresenceofasignalbetweenH-6andH-3intheNOSEYspectrum
concluded that these two protons were on the same ring side.
Compound1 possesses the relative configurationpresented in Fig. 2
with an [a] 25 D value of ꢁ21.5, which is similar to the reference
compound’svalueofꢁ20(Itoetal., 2009), suggestingthattheyhave
the sameconfigurationat the furan-lactonemoiety. However, when
compound 1 was separatedintotwo enantiomorphs, which possess
enol structures that easily transform into one another, no optical
isomer was obtained; therefore, the absolute configuration of
compound 1 was not clarified. Thus, the structure of 1 was
determinedtobe3-(2-hydroxyl-4-methyl-3-pentenyl)furan-5H-2-
one and named sibiscolactone B.
6.98 brs
7.15 brs
6.72d(8.0)
6.89 d(8.0)
7.55 d(16.0)
6.27d(16.0)
6.86 d(8.0)
7.04 d(8.0)
7.57 d(16.0)
6.29 d(16.0)
0
0
0
6.98 bars
0
0
0
0
0
0
0
6.72d(8.0)
6.89 d(8.0)
7.55 d(16.0)
6.27d(16.0)
0
3.92 dd(12.0,8.0)
3.69 dd(12.0,4.0)
4.02 dd(8.0,4.0)
4.24 dd(8.0,4.0)
4.24 dd(8.0,4.0)
4.32 dd(8.0,4.0)
4.02 dd(12.0,8.0)
3.95 dd(12.0,4.0)
66.8
2
3
4
5”
6
”
”
”
73.0
70.7
72.7
70.8
66.7
71.4
69.4
71.3
70.7
63.3
2
5
Compound 2 was isolated as a colorless oil with an ½
a
ꢀ
value of
D
”
+
8.9 (MeOH), the molecular formula of which, C10H O , was
14 3
+
derived on the base of positive HR–ESI–MS (m/z 182.0942 [M] ,
calculated for 182.0943), which is equivalent to 4 degrees of
unsaturation. The IR spectrum showed the presence of a hydroxyl
a
Multiplicity: s, singlet; d, doublet; t, triplet; dd, double doublet; m, multiplet.
ꢁ1
0
0
group (3419 cm
)
and
a
conjugated ester carbonyl group
6.98 (2H, brs, H-2, 2 ), 6.72 (2H, d, J = 8.0 Hz, H-5, 5 ), 6.89 (2H, d,
J = 8.0 Hz, H-6, 6 ) and their corresponding aromatic carbons at dC
115.1 (C-2), 115.0 (C-2 ), 115.2 (C-5), 115.3 (C-5 ), 123.0 (C-6), and
122.9(C-6 ); four oxygenated olefinic carbons at dC 146.8 (C-3),
146.8 (C-3 ), 149.6 (C-4), and 149.5 (C-4 ); two quaternary aromatic
carbons at
carbons at
revealed that there were two ABX coupled signals characteristic of
two caffeic moieties. An additional four oxygenated aliphatic
carbons and two oxymethylenes, which were similar to the signals
of sorbitol (Tao et al., 2006; Zhang et al., 1993; Li et al., 2000),
ꢁ
1
1
13
0
(
1747 cm ). Analysis of the H- and C NMR spectra indicated
0
0
that 2 was structurally similar to 1, except that 2 had a molecular
weight 2 mass units less than 1 because of the loss of two
hydrogens. The NMR spectrum of compound 2 (Table 1) showed an
0
0
0
0
extra olefinic proton signal at
carbon signals at 148.8 (C-2) and
methylene signal at 1.96, 1.89 ( 26.9) and a methenyl signal at
2.91 ( 36.7) in compound 1, indicating that compound 2 was
d
H
7.44 (H-2) and two extra olefinic
d
C
127.8 (C-1) and 127.7 (C-1 ); and two carbonyl
169.2 (C-9) and 169.2 (C-9 ). All of these signals
0
d
C
d
C
128.9 (C-3) compared to a
d
C
d
H
d
C
d
H
d
C
hydrogenated to form a double bond between C-2 and C-3. The
appearance of a signal between H-6 and H-7 in the NOSEY
spectrum suggested that the signals were on same side. Further-
more, 2 has an [a] 25 D value of +8.9, which is the opposite sign
rotation as that reported in the literature data (Ito et al., 2009).
Additionally, separation of compound 2 into two enantiomorphs
was attempted. The enol type structures easily transform into one
another, thus the absolute configuration of 2 could not be obtained.
Therefore, the structure of 2 was elucidated as 3-(2-hydroxyl-4-
methyl-3-pentenyl)furan-2-en-2(5H)-one and named sibiscolac-
tone C.
0
0
00
d
except for the downfield shift of C-1 and C-6
66.7 for compound 3 and
(
C
67.3, cf.
d
C
d
C
62.1, cf.
d
C
63.3 for the reference),
0
0
00
revealing that the C-1 and C-6 of sorbitol in compound 3 were all
substituted. Furthermore, comparing the spectral data of com-
pound 3 with the reference compound sibirate (Zhang et al., 1993)
showed their structural similarities, except that the molecular
structure of
Furthermore, the disappearance of proton and carbon signals of
OCH in 3, which existed in sibirate, verified that the ferulic acid
3 was 148 mass units greater than sibirate.
3
Compound 3 was a light yellow powder with a molecular
section in sibirate was replaced by two caffeic acid residues in
compound 3, and two caffeic acid moieties were attached to the
head and tail of sorbitol by ester linkages. The sorbitol portion was
further confirmed by the alkaloid hydrolysis of compound 3, from
which a polyhydric alcohol was obtained and identified as sorbitol
by TLC comparison with the reference as well as comparison of
NMR analysis in the literature data (Li et al., 2000). The HMBC
spectrum showed key long-range correlations between the
following proton and carbon signals: H-7 and C-1, C-2, C-6, C-8,
+
formula of C24
H
26
O
12 determined by positive HR–ESI–MS ([M] at
m/z 506.1433, calculated for 506.1424), indicating 12 degrees of
unsaturation. The IR spectrum showed the presence of a hydroxyl
ꢁ1
group (3428 cm ), two conjugated ester carbonyl groups
ꢁ1
(
1
1689 and 1701 cm ) and an aromatic ring (1632, 1598, 1515,
ꢁ
1
444, 1612, 1588, and 1516 cm ). The UV spectrum exhibited
absorption maxima at 203, 213, 296 (sh), and 322 nm, suggesting
the presence of an extensive conjugated system. 13C NMR data
0
0
0
0
0
0
0
showed 21 carbons signals, revealing that
3
possessed
a
C-9; H-8 and C-1, C-7, C-9; H-7 and C-1 , C-2 , C-6 , C-8 , C-9 ; H-8
0
0
0
00
00
0
symmetrical structure when compared with the HR-ESI–MS
and C-1 , C-7 , C-9 ; H-1 , C-9; and H-6 and C-9 as shown in Fig. 2.
Thus, compound 3 was composed of two caffeic acid moieties and a
sorbitol with a head-tail connection, i.e., 1,6-sorbitol-O-dicaffeic
acid ester, which had been previously synthesized and reported
but was obtained from natural products for the first time and its
spectral data were described.
1
13
results. The H- and C NMR and DEPT spectra of 3 (Table 2)
indicated the presence of four trans olefinic proton signals at
d
H
0
6
7
1
.22 (2H, d, J = 16.0 Hz, H-8, 8 ), and
d
H
7.55 (2H, d, J = 16.0 Hz, H-7,
147.2 (C-7),
0
) and their corresponding olefinic carbon signals of d
C
0
0
47.1 (C-7 ), 116.5 (C-8), and 116.5 (C-8 ); six aromatic protons at d
H

3
22
B. Li et al. / Phytochemistry Letters 13 (2015) 319–323
The compounds were isolated by bioassay guiding, and the
the extract (1.3 kg) was extracted with EtOH under reflux
(3 ꢂ1.5 h), and the EtOH-soluble portion was concentrated under
reduced pressure to give a brown solid material (500 g). This
material was applied to a Diaion HP 20 chromatography column
ethanol extract of the aqueous extract of S. angustata showed
effects on lipid-lowering. Additionally, the new compound
sibiskoside exhibited an anti-obesity effect (Ito et al., 2009).
Therefore, compounds from the ethanol extract were preliminarily
evaluated for hypolipidemic activities by assessing their triglycer-
ide content in HepG2 cells (Table 3). Fortunately, compared to the
control group, compounds 1–3 all showed moderate activities
and eluted successively with a gradient of EtOH/H
of the 50% EtOH elution was further subjected to silica gel column
chromatography eluted with CHCl and MeOH in a stepwise
2
O. Then, 25.8 g
3
gradient mode, the eluate of which were monitored by TLC and
similar fractions were combined to afford 10 subfractions. Sub-
fraction 2 (0.36 g) was refractioned on a silica gel column (5.0 cm i.
(
p < 0.01) in HepG2 cells, which were in accordance with our
previously reported results. The structural analysis declared that
these compounds were all esters, possibly leading to their similar
activities, and further investigations continue in our laboratory.
d., 57 cm, 360–420 mesh) eluted gradiently with CHCl
refractions 21–25 were finally purified on a silica gel column eluted
gradiently with C /(Me) CO (9:1, 8:2, 7:3). Compound 1 was
obtained from the C /(Me) CO (8:2) eluate (25 mg, recrystallized
in hexane). Subfraction 4 (2.8 g) was dissolved in methanol and
repartitioned to a silica gel column eluted gradiently with CHCl
3
/MeOH, and
H
6 6
2
3
. Experimental
6
H
6
2
3
.1. General experimental procedures
3
/
MeOH (20:1–1:1) to obtain 30 fractions. Fraction 15 (0.7 g) was
Optical rotations were measured on a JASCO P-2000 polarimeter
subjected to silica gel column chromatography (5.0 cm i.d., 100 cm,
using MeOH as the solvent. CD spectra were obtained on a JASCO J-
15 spectrometer. UV spectra were obtained on JASCO
V650 spectrophotometer. IR spectra were recorded on a Nicolet
700 FT-IR spectrometer by the microscope transmission method.
NMR spectra were obtained on an INOVA-500 MHz NMR spectrom-
3
200–300 mesh) eluted gradiently with CHCl /MeOH, from which
eluate 4 was precipitated and recrystallized by methanol to afford
3 (60 mg). 70 g of the 20% EtOH elution was subjected to silica gel
8
a
5
column chromatography (2000 g) and eluted with CHCl
O to give 15 fractions (A–O). Fraction B (15.0 g) was fractionated
on an ODS column (50 m, 400 g) eluted with a MeOH/H O solvent
3
/MeOH/
H
2
1
13
eter operating at 500 MHz for H and at 125 MHz for C. Chemical
shifts are given in (ppm) with solvent (DMSO-d or CD COCD
m
2
d
6
3
3
)
system (5:95 ! 50:50) to give 10 subfractions. Subfraction B-10
(0.7 g) was purified by preparative HPLC and eluted with 13% CAN
at a flow rate of 7 ml/min (210 nm) to obtain 2 (20 mg).
peaks used as references. GC was conducted using an Agilent 7890A
instrument (Agilent). ESI–MS spectra were measured on an Agilent
1100 SeriesLC/MSDiontrapmassspectrometer.HRESIMSdatawere
recorded on an Autospec Ultima-TOF mass spectrometer. Analytical
HPLC was run on an Agilent 1100 series instrument with a UV/DAD
3.4. Alkaloid hydrolysis and sugar analysis of compounds 3
ꢃ
detector using a YMC column (RP-C18, 4.6 ꢂ 250 mm, 5
m
m).
Compound 3 (20 mg) was refluxed in 2 M KOH (0.5 ml) at 100 C
Preparative HPLC was performed on a Shimadzu LC-6AD instru-
ment with an SPD-10A detector using a YMC-Pack ODS-A column
for 1 h and neutralized with HCl. The neutralization solution was
then partitioned by polyamide column chromatography and eluted
with MeOH to obtain caffeic acid (6 mg) and D-glucitol (5 mg), the
NMR spectral data of which match the reference values.
(
20 ꢂ 250 mm, 5
AmershamPharmaciaBiotechABFactory, Sweden. ODS(45–70
MerckKGaA,Darmstadt,Germany),DiaionHP20macroporousresin
Mitsuboshi Chemical Industries, Tokyo, Japan), and silica gel (200–
00 mesh, Qingdao Marine Chemical Inc., PR China) were used for
m
m). The Sephadex LH-20 was obtained from
m
m,
(
3
3.5. Hypolipidemic activity assays
column chromatography. TLC was performed on glass pre-coated
with silica gel GF254 (200–300 mesh, Qingdao Marine Chemical Inc.,
PR, China). Spots were visualized under UV light or byspraying with
The hypolipidemic activities of compounds 1–3 were assayed as
described previously (Wang et al., 2013).
1
0% H
.2. Plant Materials
S.angustata (Rehd.) Hand.-Mazz was collected in the Sichuan
2
SO
4
in 95% EtOH, followed by heating.
3.5.1. 3-(2-hydroxyl-4-methyl-3-pentenyl)furan-5H-2-one (1)
ꢃ
25
Colorless needles (Hexane); mp 68–70 C, [
CHCl ); UV (MeOH) max (log ) 284 (1.53), 308 (1.36) nm; IR (KBr)
max 3424 (OH),1726 (CO) cm ; HNMR (CD
D
a] -21.5 (c 1.30,
3
3
l
e
1 1
ꢁ
n
3
OD, 400 MHz) d: 5.19
(1H, dd, J = 6.4, 1.6 Hz, H-7), 4.29 (1H, ddd, J = 8.8, 8.0, 2.2 Hz, H-6),
3.90 (1H, ddd, J = 12.0, 8.4, 3.6 Hz, H-1a), 3.69 (1H, m, H-1b), 2.91
(1H, m, H-3), 1.96, 1.89 (each 1H, m, H-2), 2.00, 1.69 (each 1H, m, H-
province, China in 2002 and identified by professor Wang Tianzhi
in West China School of Pharmacy, Sichuan University, China.
5
), 1.73 (3H, d, J = 1.2 Hz, CH
3
-9), 1.70 (3H, d, J = 1.2 Hz, CH
3
-10);
+
+
3.3. Extraction and Isolation
EIMS (+) m/z 184 [M] (20), 169 [M–CH
84.1112 (calc’d for C10 , 184.1100).
3
] (100); HREIMS (+) m/z
1
16 3
H O
The air-dried and powdered aerial portion of S. angustata
(
25.5 kg) was extracted with 250 L of boiling water (3 ꢂ1 h), and
3.5.2. 3-(2-hydroxyl-4-methyl-3-pentenyl)furan-2-en-2(5H)-one (2)
2
5
the decoction was then spray-dried to yield 3.0 kg of extract. Part of
Colorless oil; [
07 (2.11), 308 (1.15) nm; IR (KBr)
a
]
D
-16.5(c 1.0, CHCl
3
); UV (MeOH)
l
max (log
e
)
;
ꢁ
1
2
nmax 3419 (OH), 1747 (CO) cm
1
Table 3
HNMR (CD
1H, dd, J = 8.5, 1.5, H-7), 4.80 (2H, d, J = 1.5 Hz, H-1), 4.70(1H, m,
OH), 4.40 (1H, m, H-6), 2.36 (1H, ddd, J = 14.5, 7.5,1.5 Hz, H-5a), 2.22
1H, ddd, J = 14.5, 7.5, 1.5 Hz, H-5b), 1.63 (3H, d, J = 1.0 Hz, CH -9),
3
1.56 (3H, d, J = 1.0 Hz, CH -10); ESIMS (+) m/z 205 [M + Na] (53),
3
OD, 400 MHz) d: 7.44 (1H, dd, J = 2.0, 1.0 Hz, H-2), 5.10
Hypolipdaemic effects of compounds 1–3 on triglyceride content in HepG2.
(
Group
Concentration
Results
(
3
model
simvastatin
1
2
3
0.3410 ꢄ 0.0113
0.1799 ꢄ 0.0109
ꢁ
ꢁ
ꢁ
ꢁ
5
5
5
5
**
*
+
10
10
10
10
M
M
M
M
+
+
0.2185 ꢄ 0.0072
387 [2 M + Na] (100); HRESIMS (+) m/z 182.0942 [M] (calc'd for
, 182.0943).
*
0.2130 ꢄ 0.0183
0.2221 ꢄ 0.0133
10 14 3
C H O
*
Data were expressed as mean ꢄ S.E.
3
.5.3. 1,6-sorbitol-O-dicaffeic acid ester (3)
Light yellow powder; UV (MeOH) max (log
2.06) nm; IR (KBr) max 3386 (OH), 1686 (CO), 1642 (CO),
*
p < 0.05.
l
e) 284 (3.32), 308
*
*
p < 0.01 vs control group.
(
n

B. Li et al. / Phytochemistry Letters 13 (2015) 319–323
323
ꢁ
1
7
597 cm 1; 1H NMR (CD
3
0
OD, 400 MHz)
d
: 7.55 (2H, d, J = 16.0 Hz, H-
References
0
0
,7 ), 6.98 (1H, brs, H-2,2 ), 6.89 (2H, d, J = 8.0 Hz, H-6,6 ), 6.72 (2H,
d, J = 8.0 Hz, H-5, 5 ), 6.27 (2H, d, J = 16.0 Hz, H-8,8 ); ESI–MS m/z 505
M-H] (100), 529 [M + Na] (80); HRESIMS (+) m/z 506.1433 (calc’d
0
0
Institute of Botany, Chinese Academy of Science, 1985. The Picture Index of Senior
China Plant, vol. II. Science Press, pp. 186.
Ito, Y., Kamo, S., Sadhu, S.K., Ohtsuki, T., Ishibashi, M., Kano, Y., 2009. Structure of
new monoterpene glycoside from Sibiraea angustata RCHD. And its anti-obestic
effect. Chem. Pharm. Bull. 57, 294–297.
ꢁ
+
[
For C24 12, 506.1424).
26
H O
Li, B., Lee, J.B., Hayashi, K., Ito, Y., Sun, W.J., Wang, X.J., Kano, Y., Hayashi, T., 2010. Two
new monoterpenes from Sibiraea angustata. J. Nat. Med. 64, 89–92.
Wang, Z.W., Li, B., Yu, S.S., Lai, X.W., Liu, B., Chen, J., Hayashi, T., 2013. Eight new
monoterpene acylglyucosides from Sibiraea angustata. Phytochem. Lett. 6, 461–
Acknowledgments
We are grateful to the Department of Instrumental Analysis, the
Institute of Materia Medica, the Chinese Academy of Medical
Sciences and Peking Union Medical College for measuring the IR,
UV, NMR, and MS spectra. We are also grateful to Mr. T. Z. Wang at
the West China School of Pharmacy, Sichuan University for the
plant identification.
4
66.
He, L., Wang, C.F., Liang, G.X., Ning, B.M., Huang, H.W., 2013. Preparation of 1,6-O-
dicaffeoyl polysorbate and derivatives for treating obesity and related diseases.
Faming Zhuanli Shenqing, CN 103214370 A 20130724.
Tao, T.T., Sei, Y., Wang, T.Z., Bai, C., Chang, Y.B., 2006. Chemical Constituents o f
Sibiraea angustata. Chin. J. Nat. Med. 4, 257–259.
Zhang, C.Z., Li, C., Feng, S.L., Zhao, C.L., Wang, W.H., 1993. Isolation and structure of
sibirate from Sibiraea angustata. Acta Pharmaceutica Sinica 28, 798–800.
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officinale Baill. China J. Chin. Mater. Med. 25, 612–614.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the
online
version,
at
http://dx.doi.org/10.1016/j.
phytol.2015.07.009.