Three new monoterpene glucosides from Sibiraea angustata

Article abstract of DOI:10.1080/14786419.2016.1201667

Three new monoterpene glycosides, named sibiraglycoside I(1), J(2) and K(3), were isolated from an aqueous extract of the aerial portion of Sibiraea angustata. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including 1D and 2D NMR and MS experiments) and compared to literature data. (Figure presented.). Three new monoterpene glucosides were isolated and identified from the plant of Sibiraea angustata.

Full text of DOI:10.1080/14786419.2016.1201667

Natural Product Research
Formerly Natural Product Letters
ISSN: 1478-6419 (Print) 1478-6427 (Online) Journal homepage: http://www.tandfonline.com/loi/gnpl20
Three new monoterpene glucosides from Sibiraea
angustata
Zhengzheng Yao, Hongdong Liu, Xianghong Xu, Xiaotian Chen, Dongming
Zhang, Xuewen Lai, Peng Xu & Bin Li
To cite this article: Zhengzheng Yao, Hongdong Liu, Xianghong Xu, Xiaotian Chen, Dongming
Zhang, Xuewen Lai, Peng Xu & Bin Li (2016): Three new monoterpene glucosides from Sibiraea
angustata, Natural Product Research, DOI: 10.1080/14786419.2016.1201667
To link to this article: http://dx.doi.org/10.1080/14786419.2016.1201667
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Date: 07 July 2016, At: 10:14

Natural Product research, 2016
http://dx.doi.org/10.1080/14786419.2016.1201667
Three new monoterpene glucosides from Sibiraea angustata
Zhengzheng Yaoa, Hongdong Liua,b, Xianghong Xua, Xiaotian Chena,
Dongming Zhangc, Xuewen Laia, Peng Xua and Bin Lia
aPharmacy college, Jiangxi university of traditional chinese Medicine, Nanchang, P.r. china; btechnology
c
center, Jiangzhong group, Nanchang, P.r. china; Institute of Materia Medica, chinese academy of Medical
sciences and Peking union Medical college, Beijing, P.r. china
ABSTRACT
ARTICLE HISTORY
received 24 November 2015
accepted 29 May 2016
Three new monoterpene glycosides, named sibiraglycoside I(1), J(2)
and K(3), were isolated from an aqueous extract of the aerial portion
of Sibiraea angustata. Their structures were elucidated on the basis of
extensive spectroscopic data analysis (including 1D and 2D NMR and
MS experiments) and compared to literature data.
KEYWORDS
Sibiraea angustata;
rosaceae; sibiraglycoside
I; sibiraglycoside J;
sibiraglycoside K
HO
O
O
OH
OH
HO
R
O
Three new monoterpene glucosides were isolated and identified from
the plant of Sibiraea angustata.
1. Introduction
Sibiraea angustata (Rosaceae) is a shrub, widely distributed in the western part of China,
including Qinghai, Gansu, Sichuan, Xizang and Yunnan provinces, whose leaves and twig
could be used as a common and civil traditional medicine in Tibet, for the treatment of
indigestion and upset stomach for many years, known as ‘Liucha’. And long term usage of
Liucha benefits human body and reduces lipids (Institute of Botany 1985). As for, thorough
chemical and bioactive studies have been performed on this plant, leading to the isolation
of many active constituents, such as terpenes, phenolic acid, phenolic ester, saponins, volatile
oils and polysaccharides (Yan et al. 2007; Xie et al. 2011; Wang et al. 2014). In our previous
CONTACT Bin li
lbin@jzjt.com
supplemental data for this article can be accessed at http://dx.doi.org/10.1080/14786419.2016.1201667.
© 2016 Informa uK limited, trading as taylor & Francis Group

2
Z. YAO ET AL.
papers, the identification of 13 monoterpenes and monoterpene glycosides (Ito et al. 2009;
Li et al. 2010, 2015; Wang et al. 2013), as well as a dicaffeic acid ester (Li et al. 2015) from the
plant were reported, and the monoterpene glycosides showed significant anti-obesity activ-
ity. In our continual research, the isolation and structural elucidation of three new monoter-
pene glycosides, sibiraglycoside I (1), sibiraglycoside J (2) and sibiraglycoside K (3) from the
aerial part of S. angustat was presented.
2. Results and discussion
The powdered residue of the aqueous extract from the aerial part of S. angustata was
extracted by the ethanol first, and the extraction was concentrated under reduced pressure
to yield a solid brown material, which was applied to a Diaion HP-20 chromatography column
eluting with a gradient of C2H5OH/H2O. Fortunately, three new monoterpene glycosides,
sibiraglycoside I (1), sibiraglycoside J (2) and sibiraglycoside K (3) were obtained from the
20% Ethanol fraction by next various column chromatography (CC). Their structures were
elucidated by extensive spectroscopic methods including 1D (1H, 13C NMR) and 2D NMR
(HSQC, HMBC, 1H–1H COSY and ROESY) experiments as well as HRESI-MS and ESI-MS analysis
and by comparison with those of the literature data.
Compound 1 was obtained as a colourless gum with an [ꢀ]2D0 value of −24.8 (c 0.001,
CH3OH), the molecular formula of which was determined to be C16H28O8 from the molecular
ion peak at m/z 371.1675 [M + Na]+ (Calcd for 371.1676) in the HRESI-MS, indicating 3° of
unsaturation. The IR spectrum showed absorption bands characteristic of a hydroxyl group
(3388 cm−1), a conjugated carbonyl group (1675 and 1611 cm−1). The UV spectrum exhibited
absorption maxima at 251 nm (log ε = 2.59). The 1H NMR, 13C NMR and HSQC spectra of 1
exhibited signals attributed to two methyls at δH 1.14 (δC 29.6) and δH 1.14 (δC 29.7), one
methyl at δH 2.06 (δC 19.0) which may connect with an olefinic carbon according to the
downfield shift of the methyl; one olefinic methine signal with a proton at δH 6.26 (H-4) and
a carbon at δC 126.2 (C-4); an oxygenated methylene group with protons at δH 3.89, 3.60
(H-1) and carbon at δC 66.4 (C-1); and two methylenes with signals at δH 2.37 (H-2), δC 40.2
(C-2) and δH 2.50 (H-6), δC 56.7 (C-6). 13C NMR spectrum showed an olefinic quaternary carbon
at δC 153.4 (C-3), a carbonyl carbon at δC 200.0 (C-5), an oxygenated quaternary carbon at
δC 69.0 (C-7) in addition to the above carbons.
These spectroscopic features along with two sp2 carbon signals (one double bond) at δC
153.4 (C-3) and δC 126.2 (C-4) in the 13C NMR and the 1H–1H COSY correlations (H-1 and H-2)
suggested that 1 is an oxygenated geraniol monoterpene. The HMBC spectrum showed key
long-range correlations from the following proton to carbon signals: H-1 to C-2, C-1′, C-3;
H-2 to C-1, C-3, C-4, C-10; H-4 to C-2, C-3, C-5, C-10; H-6 to C-4, C-5, C-7, C-8, C-9; H-8 to C-6,
C-7, C-9; H-9 to C-6, C-7, C-8; H-10 to C-2, C-3, C-4, C-5, also declaring the existence of a
geraniol monoterpene. Furthermore, two methyl signals (H-8 and H-9) showed correlations
to the carbon signals at C-6 and C-7, indicating two methyls were all connected to C-7.
1 contained a hexose moiety which was identified as a glucose from the methyl-1-O-
glucoside obtained on methanolysis. The configuration of the glycosidic linkage was β as
based on the coupling constant of the anomeric proton at δH 4.15 (d, J = 7.8 Hz). The sugar
β-d-glucose was also identified by GC analysing the trimethylsilyl ether derivatives of its
acidic hydrolysis products with standard sugars (Ito et al. 2009). In the ROESY spectrum signal
at δH 2.37 (H-2) showed long correlations with signal at δH 6.26 (H-4) declaring these two

NATURAL PRODUCT RESEARCH
3
4
6
8
10
7
3
5
HO
O
HO
HO
O
O
2
9
6
4
8
3
7
5
1 O
1
OH
OH
2
O
OH
OH
HO
HO
O
9
10
HO
4
6
8
10
7
3
5
HO
O
HO
O
O
2
6
4
9
8
3
7
5
1
O
1
OH
OH
2
O
OH
OH
HO
O
10
9
HO
Figure 1. structures of compounds 1–4.
protons occupied the same sides, so the geometry of double bond is E. Thus, the structure
of 1 was determined to be 3,7-dimethyl-7-hydroxy-3(E)-octene-5-one-1-O-β-d-glucopyra-
noside and named sibiraglycoside I (Figure 1).
Compound 2 was obtained as a colourless gum with an[ꢀ]2D0 value of −9.0 (c 0.001, CH3OH),
the molecular formula of which was determined to be C16H28O8 from the molecular ion peak
at m/z 371.5321 [M + Na]+ (Calcd for 371.5336) in the HRESI-MS, indicating 3° of unsaturation.
The IR spectrum showed absorption bands characteristic of a hydroxyl group (3397 cm−1),
a conjugated carbonyl group (1673 and 1610 cm−1). The UV spectrum exhibited absorption
maxima at 252 nm (log ε = 2.79). The spectral data are very similar to those of 1. The differ-
ences are a downfield shift of the allylic methylene group [δH 2.78 (2H, t, H-2)] in 2 from [δH
2.37 (2H, t, H-2)] in 1, and an upfield shift of the vinyl methyl group [δH 1.90 (3H, s, H-10)] in
2 from [δH 2.06 (3H, s, H-10)] in 1. Thus, 2 was presumed to have a structure in which the
double bond was isomerised to the Z-configuration. In fact, the appearance of a signal
between H-4 and H-10 in the NOESY spectrum suggested that these protons were long
correlations, so the geometry of double bond is Z. Thus, the structure of 2 was elucidated
as 3,7-dimethyl-7-hydroxy-3(Z)-octene-5-one-1-O-β-d-glucopyranoside and named sibi-
raglycoside J (Figure 1).
Compound 3 was obtained as a colourless gum with an [ꢀ]2D0 value of −11.2 (c 0.001,
CH3OH), the molecular formula of which was determined to be C16H28O7 from the molecular
ion peak at m/z 355.2322 [M + Na]+ (Calcd for 355.2317) in the HRESI-MS, indicating 3° of
unsaturation. The IR spectrum showed absorption bands characteristic of a hydroxyl group
(3386 cm−1), a conjugated carbonyl group (1673 and 1612 cm−1). The UV spectrum exhibited
absorption maxima at 255 nm (log ε = 2.43). The spectral data are very similar to those of
3,7-dimethyl-3(Z)-octene-5-one-1-O-β-d-glucoside (compound 4) (He et al. 2013). The dif-
ferences are an upfield shift of the allylic methylene group [δH 2.37 (2H, t, H-2)] in 3 from
[δH 2.92 (2H, m, H-2)] in 4 and a downfield shift of the vinyl methyl group [δH 2.07 (3H, s,
H-10)] in 3 from [δH 1.98 (3H, s, H-10)] in 4. Thus, 3 was presumed to have a structure in which
the double bond with the E-configuration isomerising to compound 4 with Z-configuration.
In addition, according to the facts that the NMR spectra data of 3 exhibited a methylene
with signals at δH 2.37 (H-2), δC 40.1 (C-2) and 1 exhibited a methylene with signals at δH 2.37

4
Z. YAO ET AL.
(H-2), δC 40.2 (C-2), it also could be concluded that they were all trans-oriented. Thus, the
structure of 3 was elucidated as 3,7-dimethyl-3(E)-octene-5-one-1-O-β-d-glucopyranoside
and named sibiraglycoside K (Figure 1).
3. Experimental
3.1. General procedures
Optical rotations were measured on a Perkin Elmer 241 automatic digital polarimeter using
Ethanol as solvent. UV spectra were recorded on a Shimadzu UV-300 spectrophotometer. IR
spectra were recorded on a Nicolet 5700 FT-IR spectrometer by a transmission microscope
method. NMR spectra were obtained on an INOVA-500 and Mercury-400 spectrometers in
DMSO-d6 with solvent peaks as references (δH 2.50, δC 39.7). GC was conducted using an
Agilent 7890A instrument (Agilent). HRESI-MS and ESI-MS spectra were measured on an
Agilent 1100 Series LC/MSD ion trap mass spectrometer. Analytical HPLC was run on a
Shimadazu LC-15C instrument with a SPD-10A detector using a YMC column (RP-C18,
4.6 × 250 mm, 5 μm). Preparative HPLC was performed on a Shimadzu LC-6AD instrument
with an SPD-20A detector using a YMC-Pack ODS-A column (250 × 20 mm, 5 μm). The
Sephadex LH-20 was obtained from Amersham Pharmacia Biotech AB Factory, Sweden. CC
was performed with Diaion HP20 macroporous resin (Mitsuboshi Chemical Industries, Tokyo
Japan), silica gel (60–100 and 200–300 mesh, Qingdao Marine Chemical Inc, PR China) and
ODS (50 μm, YMC, Japan). TLC was carried out on glass precoated with silica gel GF254 plates
(Qingdao Marine Chemical Inc, PR China). Spots were visualized under UV light or by spraying
with 5% vanillin–sulphuric acid solution followed by heating.
3.2. Plant Material
S. angustata was collected in the Sichuan province, China in 2002 and identified by professor
Wang Tianzhi in West China School of Pharmacy, Sichuan University, China, and a voucher
specimen number specimen (001612) had been deposited in Herbarium of Jiangxi University
of Traditional Chinese Medicine.
3.3. Extraction and isolation
The air-dried and powdered aerial portion of S. angustata (25.5 kg) was extracted with
250 L of boiling water (3 × 1 h), and the decoction was then spray-dried to yield 3.0 kg
of extract. Part of the extract (1.3 kg) was extracted with ethanol under reflux (3 × 1.5 h),
and the ethanol-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 and eluted successively with a gradient of C2H5OH/H2O. The 20% Ethanol fraction
(40 g) was subjected to silica gel CC (800 g) and eluted with CHCl3/CH3OH to give 13
fractions (A1–A13). Fraction A5 (1.0 g) was subjected to Sephadex LH-20 (Methanol)
chromatography to give seven subfractions (A5-1–A5-7). Compound 1 (15 mg) and
compound 2 (10 mg) were obtained from subfraction A5-2 (110 mg) by two rounds of
continuous preparative HPLC, eluting first with 25% Methanol and second with 12%
acetonitrile on a YMC-Pack ODS-A column (250 × 20 mm, 5 μm) at a flow rate of 7

NATURAL PRODUCT RESEARCH
5
mL/min and UV detection at 254 nm. Fraction A2 (5.5 g) was subjected to ODS
chromatography column (50 μm, 9 g) with a CH3OH/H2O solvent system to give six
subfractions (A2-1–A2-6). Subfraction A2-2 (1.3 g) was further fractionated to Sephadex
LH-20 (Methanol) chromatography to give seven subfractions (A2-2-1–A2-2-6).
Subfraction A2-2-1 (271 mg) was purified by preparative HPLC and eluted with 15%
acetonitrile at a flow rate of 7 mL/min (254 nm) to obtain compound 3 (5 mg).
3.4. Acid hydrolysis and sugar analysis of compounds 1, 2 and 3
Compounds 1–3 (each 3 mg) were refluxed in 2 M HCl (3 mL) at 60 °C for 3 h and concen-
trated to give a brown material, then dissolved in water (3 mL) and partitioned by Ethyl
Acetate (3 mL × 3), the aqueous layer was evaporated to dryness under reduced pressure
to give the three monosaccharide residues. The absolute configuration of the monosaccha-
ride was determined based on a reported literature (e.g. Kinjo et al. 1992). Authentic mon-
osaccharide samples were trimethylsilylated by l-cysteine methyl ester hydrochloride and
N-trimethylsilylimidazole. Then the derivatives were analysed by GC, and the retention times
(tR) were as follows:
d
-glucose at 19.83 min and -glucose at 20.01 min. The monosaccharides
l
obtained from the acid hydrolysis of compounds 1–3 were treated in a similar manner to
the authentic monosaccharide samples and were both identified as d-glucose (19.83 min),
which are matched to the standard d-glucose.
3.5. sibiraglycoside I (1)
Colourless gum; [ꢀ]2D0: −24.8 (c 0.001, CH OH); UV (CH OH) λmax (log ε) 251 (2.59) nm; IRvmax
3
3
1
3388, 2972, 2928, 1675, 1611, 1375, 1203, 1159, 1079, 904, 628 cm−1; H NMR (DMSO-d6,
500 MHz) δH: 3.89 (1H, dt, J = 9.8, 6.9 Hz, H-1a), 3.60 (1H, dt, J = 9.8, 6.8 Hz, H-1b), 2.37 (2H, t,
J = 6.8 Hz, H-2), 6.26 (1H, s, H-4), 2.50 (2H, m, H-6), 1.14 (6H, s, H-8, 9), 2.06 (3H, s, H-10), 4.15
(1H, d, J = 7.8 Hz, H-1′), 2.93 (1H, td, J = 8.4, 5.0 Hz, H-2′), 3.12 (1H, m, H-3′, 4′), 3.03 (1H, m,
H-5′), 3.67 (1H, m, H-6′a), 3.43 (1H, dt, J = 11.7, 5.8 Hz, H-6′b); 13C NMR (DMSO-d6, 125 MHz)
δC: 66.4 (C-1), 40.2 (C-2), 153.4 (C-3), 126.2 (C-4), 200.0 (C-5), 56.7 (C-6), 69.0 (C-7), 29.6 (C-8),
29.7 (C-9), 19.0 (C-10), 102.8 (C-1′), 73.4 (C-2′), 76.7 (C-3′), 76.9 (C-4′), 70.1 (C-5′), 61.1 (C-6′);
ESI-MS m/z 371 [M + Na]+, 719 [2M + Na]+; HRESI-MS m/z 348.1783 [M]+ (Calcd for C16H28O8
348.1784).
3.6. sibiraglycoside J (2)
Colourless gum; [ꢀ]2D0: –9.0 (c 0.001, CH OH); UV (CH OH) λ (log ε) 252 (2.79) nm; IRvmax
3
3
max
1
3397, 2973, 2928, 1673, 1610, 1441, 1379, 1160, 1080, 904, 863, 720, 630 cm−1; H NMR
(DMSO-d6, 400 MHz) δH: 3.83 (1H, dd, J = 16.3, 7.2 Hz, H-1a), 3.54 (1H, dd, J = 16.5, 7.2 Hz,
H-1b), 2.78 (2H, t, J = 7.0 Hz, H-2), 6.25 (1H, s, H-4), 2.50 (2H, m, H-6), 1.14 (6H, s, H-8, 9), 1.90
(3H, s, H-10), 4.13 (1H, d, J = 7.8 Hz, H-1′), 2.93 (1H, td, J = 8.2, 5.2 Hz, H-2′), 3.08 (1H, m, H-3′~5′),
3.65 (1H, m, H-6′a), 3.43 (1H, dt, J = 11.5, 5.6 Hz, H-6′b); 13C NMR (DMSO-d6, 100 MHz) δC: 67.1
(C-1), 33.6 (C-2), 154.4 (C-3), 126.7 (C-4), 199.7 (C-5), 56.7 (C-6), 69.1 (C-7), 29.7 (C-8), 29.7 (C-9),
25.8 (C-10), 102.8 (C-1′), 73.5 (C-2′), 76.8 (C-3′), 76.9 (C-4′), 70.0 (C-5′), 61.1 (C-6′); ESI-MS m/z
371 [M + Na]+, 719 [2M + Na]+.

6
Z. YAO ET AL.
3.7. sibiraglycoside K (3)
Colourless gum; [ꢀ]2D0: –11.2 (c 0.001, CH OH); UV (CH OH) λmax (log ε) 255 (2.43) nm; IRvmax
3
3
3386, 2973, 2928, 1673, 1612, 1379, 1210, 1159, 1080, 904, 863, 627 cm−1; 1H NMR (DMSO-d6,
400 MHz) δH: 3.89 (1H, dt, J = 9.4, 6.9 Hz, H-1a), 3.60 (1H, dt, J = 9.2, 6.8 Hz, H-1b), 2.37 (2H, t,
J = 6.6 Hz, H-2), 6.20 (1H, s, H-4), 2.28 (2H, d, J = 6.9 Hz, H-6), 2.03 (1H, m, H-7), 0.86 (3H, d,
J = 6.6 Hz, H-8), 0.85 (3H, d, J = 6.6 Hz, H-9), 2.07 (3H, s, H-10), 4.15 (1H, d, J = 7.8 Hz, H-1′),
2.93 (1H, t, J = 8.3 Hz, H-2′), 3.11 (1H, m, H-3′, 4′), 3.02 (1H, m, H-5′), 3.67 (1H, d, J = 11.7 Hz,
H-6′a), 3.43 (1H, dd, J = 11.7, 5.7 Hz, H-6′b); 13C NMR (DMSO-d6, 100 MHz) δC: 66.3 (C-1), 40.1
(C-2), 153.8 (C-3), 124.6 (C-4), 200.3 (C-5), 52.7 (C-6), 24.4 (C-7), 22.4 (C-8), 22.4 (C-9), 19.0
(C-10), 102.8 (C-1′), 73.3 (C-2′), 76.8 (C-3′), 76.9 (C-4′), 70.1 (C-5′), 61.1 (C-6′); ESI-MS m/z 355
[M + Na]+.
3.8. 3,7-dimethyl-3(Z)-octene-5-one-1-O-β-D-glucopyranoside (4)
Colourless needles; 1H NMR (CD3OD, 400 MHz) δH: 3.98 (1H, dt, J = 9.4, 7.2 Hz, H-1a), 3.72 (1H,
m, overlapped, H-1b), 2.92 (2H, m, H=2), 6.23 (1H, s, H=4), 2.31 (2H, d, J = 7.0 Hz, H=6), 2.10
(1H, m, H=7), 0.92 (6H, d, J = 6.6 Hz, H=8, 9), 1.98 (3H, s, H=10), 4.30 (1H, d, J = 7.7 Hz, H=1′),
3.16 (1H, t, J = 8.0, 8.7 Hz, H=2′), 3.32 (1H, m, H=3′), 3.35 (1H, m, H=4′),3.28 (1H, brd, J = 6.4 Hz,
H=5′), 3.86 (1H, d, J = 12.0 Hz, H=6′a), 3.68 (1H, dd, J = 12.0, 3.2 Hz, H=6′b); 13C NMR (CD3OD,
100 MHz) δC: 69.2 (C-1), 35.3 (C-2), 157.9 (C-3), 126.3 (C-4), 203.1 (C-5), 54.3 (C-6), 26.4 (C-7),
22.9 (C-8), 22.9 (C-9), 26.3 (C-10), 104.3 (C-1′), 73.0 (C-2′), 75.8 (C-3′), 76.0 (C-4′), 69.5 (C-5′),
60.7 (C-6′).
4. Conclusion
From an aqueous extract of the aerial portion of S. angustata, three new monoterpene
glycosides named sibiraglycoside I, J and K were isolated and their structures were elucidated
on the basis of the spectroscopic evidence.
Supplementary material
Supplementary material relating to this article is available online, alongside Figures S1–S2.
Acknowledgements
The authors 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.
Disclosure statement
No potential conflict of interest was reported by the authors.

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7
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