Two novel lignans from Gaultheria yunnanensis

Article abstract of DOI:10.1080/10286020.2014.898634

Two new lignans, 9-salicyl-(+)-isolariciresinol (1) and gaultheroside G (2), together with seven known compounds, were isolated from the ethanolic extract of the whole plant of Gaultheria yunnanensis. Their structures were determined by extensive NMR and MS analyses. Gaultheroside G (2) was found to have an unusual ether linkage between the 2 and 9′ positions of aryl-tetralin lignan skeleton. All nine compounds were assayed for inhibitory effects against nitric oxide and pro-inflammatory cytokines TNF- and IL-6 release in LPS-induced RAW 246.7 macrophages, while no significant activities were observed for the evaluated compounds. 2014

Full text of DOI:10.1080/10286020.2014.898634

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Two novel lignans from Gaultheria
yunnanensis
a
ab
a
a
Yan-Ping Gao , Yun-Heng Shen , Xi-Ke Xu , Jun-Mian Tian , Hua-
a
a
a
abcd
Wu Zeng , Sheng Lin , Chun-Mei Liu & Wei-Dong Zhang
a
Department of Phytochemistry, School of Pharmacy, Second
Military Medical University, Shanghai 200433, China
b
Research Center of Natural Resources of Chinese Medicinal
Materials and Ethenic Medicine, Jiangxi University of Traditional
Chinese Medicine, Nanchang 330004, China
c
King Saud University, Riyadh 11451, Saudi Arabia
Click for updates
d
School of Pharmacy, Shanghai Jiao Tong University, Shanghai
200240, China
Published online: 26 Mar 2014.
To cite this article: Yan-Ping Gao, Yun-Heng Shen, Xi-Ke Xu, Jun-Mian Tian, Hua-Wu Zeng, Sheng
Lin, Chun-Mei Liu & Wei-Dong Zhang (2014) Two novel lignans from Gaultheria yunnanensis, Journal
of Asian Natural Products Research, 16:7, 724-729, DOI: 10.1080/10286020.2014.898634
To link to this article: http://dx.doi.org/10.1080/10286020.2014.898634
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Journal of Asian Natural Products Research, 2014
Vol. 16, No. 7, 724–729, http://dx.doi.org/10.1080/10286020.2014.898634
Two novel lignans from Gaultheria yunnanensis
ab
Yan-Ping Gao , Yun-Heng Shen *, Xi-Ke Xu , Jun-Mian Tian , Hua-Wu Zeng ,
a
a
a
a
a
Sheng Lin , Chun-Mei Liu and Wei-Dong Zhang
a
abcd
*
a
Department of Phytochemistry, School of Pharmacy, Second Military Medical University, Shanghai
b
00433, China; Research Center of Natural Resources of Chinese Medicinal Materials and Ethenic
2
c
Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China; King
d
Saud University, Riyadh 11451, Saudi Arabia; School of Pharmacy, Shanghai Jiao Tong
University, Shanghai 200240, China
(
Received 25 October 2013; final version received 23 February 2014)
Two new lignans, 9-salicyl-(þ)-isolariciresinol (1) and gaultheroside G (2), together
with seven known compounds, were isolated from the ethanolic extract of the whole
plant of Gaultheria yunnanensis. Their structures were determined by extensive NMR
and MS analyses. Gaultheroside G (2) was found to have an unusual ether linkage
0
between the 2 and 9 positions of aryl-tetralin lignan skeleton. All nine compounds
were assayed for inhibitory effects against nitric oxide and pro-inflammatory cytokines
TNF-a and IL-6 release in LPS-induced RAW 246.7 macrophages, while no significant
activities were observed for the evaluated compounds.
Keywords: Gaultheria yunnanensis; Ericaceae; lignans; anti-inflammatory activity
1
.
Introduction
gaultheroside G (2), together with seven
known lignans (3–9) (Figure 1), were
isolated from the title plant. This paper
describes the isolation and structural
elucidation of the new compounds (1 and
Gaultheria yunnanensis (Franch.) Rehd,
widely distributed in south and southwest
China, belongs to the genus Gaultheria
(Ericaceae family) [1]. This plant has long
2), as well as anti-inflammatory activity
evaluation of all isolates.
been used for the treatment of swelling and
pain, trauma, chronic tracheitis, and
especially rheumatoid arthritis. Phyto-
chemical investigations on the root of
G. yunnanensis have led to the isolations
of lignans, flavonoids, diterpenoids, triter-
penoids, fatty acids, coumarins, and sterols
2
.
Results and discussion
The EtOAc-soluble fraction of the etha-
nolic extract of G. yunnanensis was
subjected repeatedly to column chroma-
tography (CC) on silica gel, Sephadex
LH-20, and preparative silica gel TLC, to
yield two new lignans, together with seven
known lignans.
[2]. Zhang et al. [3] reported that salicylate
derivatives are major analgesic and anti-
inflammatory constituents in G. yunna-
nensis, of which gaultherin is a potential
inhibitor of pain and acute inflammation
similar to nonsteroidal anti-inflammation
drugs. In our continuing effort for other
bioactive constituents from this medicin-
ally important plant, two new lignans,
Compound 1 was obtained as brown
oil with a molecular formula C H O
7 28 8
2
based on its positive HR-ESI-MS data
þ
1
at m/z 503.1685 [M þ Na] . The
H
NMR data indicated the presence of one
9
-salicyl-(þ)-isolariciresinol (1) and
*Corresponding authors. Email: shenyunheng@hotmail.com; wdzhangy@hotmail.com
q 2014 Taylor & Francis

Journal of Asian Natural Products Research
725
7
′
3
′
1′
8′
OH
7
7
'
9'
H CO
3
HO
O
1″
H CO
H CO
3'
1'
8'
9
3
OH
OH
3
OH O
OH
2"
9′
O
OH
8
8
5″
7
O
″
HO
HO
5′
7
HO
1
"
H CO
1
O
R'
R
5
'
9
3
6
"
4"
5
3
3
5
H CO
OCH3
OCH3
3
OCH3
OH
OH
OH
R
R'
1
2
5
7
OCH3 OCH3
H
H
R '
1
OH
H CO
H CO
3
3
OH
O
OH
O
OCH3
HO
HO
O
Xyl
Ara
H
H CO
3
H
O
R1
HO
H CO
3
OCH3
OCH3
OH
OH
OCH3
6
8
R1
OCH3
H
R '
OCH3
H
1
3
4
O
Xyl
OH
O
HO
OCH3
OCH3
9
Figure 1. Chemical structures of 1–9.
1
6
6
,3,4-trisubstituted aromatic system [dH
.57 (d, J ¼ 1.8 Hz), 6.84 (d, J ¼ 7.8 Hz),
7.76 (dd, J ¼ 8.4, 1.8 Hz), d 112.4, 117.7,
C
119.2, 129.6, 135.8, 161.7, 170.1] in 1,
indicating that the structure of 1 consisted
of isolariciresinol and salicyl moieties.
Although no direct HMBC correlation
between salicyl and isolariciresinol moi-
eties was observed, the C-9 chemical
0
0
0
0
.63 (dd, J ¼ 7.8, 1.8 Hz)], one 1 ,3 ,4 ,6 -
tetrasubstituted aromatic system [d 6.65
H
(s), 6.34 (s)], and two methoxyls (d 3.76,
H
3
observation of three methylenes (d 32.6,
.87). The above data, together with the
C
6
3
1
1
4.7, 65.0), three methines (d 47.8, 43.3,
C
shift (d 64.7) of 1 was shifted downfield
C
8.3), and two phenyls (d 111.3, 114.5,
C
by ca. 2.6 ppm relative to that of (þ)-
22.3, 135.8, 144.5, 146.8, and d 110.3,
C
isolariciresinol (d 62.1), indicating that
C
15.3, 127.4, 132.3, 143.8, 145.1) in the
C NMR and DEPT spectra, implied that
was an aryl-tetralin-type lignan. Com-
the salicyl group should be linked to
0
1
3
the C-9 position, not C-9 position.
The relative configuration of 1 was
determined to be identical to that of (þ)-
1
parison of its NMR spectroscopic data
with those of known (þ)-isolariciresinol
isolariciresinol on the basis of the NOESY
0
(
7) [4] showed quite similarity with the
correlations of H -9 with H-6, and
2
0
exception of an additional salicyl group
dH 6.98 (d, J ¼ 8.4 Hz), 7.47 (ddd,
J ¼ 8.4, 8.4, 1.8 Hz), 6.86 (t, J ¼ 8.4 Hz),
H-8 with H -9 , together with the large
2
[
coupling constant at H-7 (J ¼ 9.0 Hz).
The positive optical rotation value of

7
26
Y.-P. Gao et al.
1
D
7
1
(½aꢀ þ 10) also supported the
an additional b-D-xylose moiety in 2,
suggesting that compound 2 might be a
lyoniresinol derivative. In the HMBC
spectrum, the anomeric proton (dH 4.19)
of xylose showed a strong correlation with
C-9 (dC 73.0), in combination with the
chemical shift of C-9 being downfield
shifted by ca.10 ppm. This indicated that
the xylose moiety was attached to the C-9
position of 2. Considering 11 degrees of
unsaturation in the structure of 2, there
should be one additional ring system.
above deduction. Therefore, structure 1
was characterized as 9-salicyl-(þ)-iso-
lariciresinol.
Analysis of the HR-ESI-MS of
gaultheroside G (2) gave a molecular
formula of C H O with 11 degrees of
2
7 34 12
1
13
unsaturation. The H and
C NMR
spectroscopic data displayed features of
the same aryl-tetralin-type lignan as 1,
including a 1,2,3,4,5-pentasubstituted aro-
matic system [d 6.23 (s), d 102.3, 125.5,
36.8, 147.5, 148.5, 154.0], a 1 ,3 ,4 ,5 ,6 -
pentasubstituted aromatic system [d 6.45
H
C
0
0
0
0
0
0
1
The key HMBC correlation from H -9 (d
2
H
3.72, 4.37) to C-2 (d 154.0) also indicated
C
H
(
s), d 107.5, 124.0, 127.5, 138.2, 146.8,
C
the presence of an ether linkage between
0
1
8
4
4
1
47.9], three methylenes (dC 30.2, 73.0,
1.4), and three methines (d 31.7, 35.5,
C-2 and C-9 (Figure 2). The observation
0
of the downfield-shifted C-9 (d 81.4,
C
C
2.7). Moreover, a pentose moiety [dH
.19, 3.19, 3.28, 3.45, 3.75, and 3.12, dC
05.3, 75.1, 78.0, 71.3, 66.9] with a
shifted by ca. 16 ppm) and C-2 (d 154.0,
C
shifted by ca. 48 ppm), as well as the
0
highfield-shifted C-8 (d 35.5, shifted by
C
b-anomeric configuration based on the
large J100 00-coupling constant (J ¼ 7.2 Hz)
ca. 4 ppm) and C-1 (d 125.5, shifted by
C
ca. 12 ppm), also strongly supported the
above deduction. The aglycone of 2 has
previously been reported in a Japanese
patent [6], and its NMR data are in good
agreement with those of 2. Therefore, the
structure 2 was established as shown. The
NOESY spectrum of 2 showed key
,2
of the anomeric proton (d 4.19) was
H
1
13
observed in the H and C NMR spectra
of 2. Acid hydrolysis of 2 afforded D-
xylose, which was verified by co-TLC
analysis of the sugar in the acid hydro-
lysate with authentic D-xylose, in combi-
nation with the optical rotation value of
correlations from H-7 to H-9 (dH 3.51),
0
2
4
xylose (½aꢀ þ 42 (c ¼ 0.13, MeOH)).
from H-8 to H-9 (d 3.88), and from H-6
H
D
0
When compared with known lignan
lyoniresinol (5) [5], their NMR data are
quite similar with exception of the absence
of one aromatic proton and the presence of
to H-9 (d 3.72), indicating that H-7 and
H
0
H-8 were co-facial, while the H-8 had the
opposite orientation (Figure 3). In the CD
spectrum of 2 (see Supplementary data),
H CO
OH
3
H CO
HO
O
3
OH O
O
OH
O
OH
HO
HO
H CO
O
3
OCH3
H CO
OCH3
3
OH
OH
1
2
1
1
H- HCOSY
HMBC
Figure 2. Selected H– H COSY and HMBC correlations of 1 and 2.
1
1

Journal of Asian Natural Products Research
727
H CO
HO
O
OH
3
H CO
3
OH O
O
OH
OH
O
HO
H CO
HO
3
O
OCH3
H CO
3
OCH3
OH
OH
1
2
Figure 3. Key NOESY correlations of 1 and 2.
besides two strong positive cotton effects
D1 þ 12.24 at 215 nm and D1 þ 6.04 at
Switzerland), whereas NMR spectra were
run on Bruker 300 and 600-MHz NMR
spectrometers (Bruker), with chemical
shifts recorded as d values. HR-ESI-MS
were determined by a Q-TOF micro mass
spectrometer (Agilent, Santa Clara, CA,
USA). CC was performed using silica gel
(200–300 mesh and 100–200 mesh;
Huiyou Silica Gel Development Co. Ltd,
Yantai, China) and Sephadex LH-20 (40–
70 mm; Amersham Pharmacia Biotech Ab,
Uppsala, Sweden).
2
41 nm, a weak positive cotton effect 0.57
at 284 nm was also observed. Therefore,
according to Kylne et al. [7], the absolute
configuration of C-7 in 2 should be R,
while the absolute configurations of C-8
0
and C-8 were assigned to be S, S,
respectively. Consequently, the structure
of 2 was established as 9-O-b-D-xylopyr-
0
anosyl-2,9 -cyclic ether-(–)-lyoniresinol,
and named gaultheroside G.
By comparing the physical and spectro-
scopic data with those reported in the
literature, known compounds were eluci-
dated as (þ)-syringaresinol (3) [8], (þ)-
pinoresinol (4) [8], (þ)-lyoniresinol (5)
3
.2 Plant material
The whole plant of G. yunnanensis was
collected in the Gaopo Village of Guiyang
City, Guizhou Province, China, in July
[
5], gaultheroside A (6) [9], (þ)-isolaricir-
2007 and identified by Prof. Shun-Zhi He
esinol (7) [10], (–)-isolariciresinol-2a-O-b-
D-xylopyranoside (8) [9], and 2,3-dihydro-
of Guiyang University of Traditional
Chinese Medicine. A herbarium specimen
is deposited in the School of Pharmacy,
Second Military Medical University,
China (herbarium No. 2007-07-16).
0
0
7
nyl)-3a-O-b-D-xylopyranosyloxy-methyl-
-methoxy-2-(4 -hydroxy-3 -methoxyphe-
5
-benzofuranpropanol (9) [11].
3
.
Experimental
3
.1 General experimental procedures
3.3 Extraction and isolation
Optical rotations were measured on a
Perkin-Elmer 341 digital polarimeter
Air-dried whole plants of G. yunnanensis
(20 kg) were powdered and extracted with
(
Perkin-Elmer, Norwalk, CT, USA). UV
spectra were recorded on a Shimadzu UV-
550 spectrometer (Shimadzu, Nakagyo
EtOH–H O (95:5, 50 l) at room tempera-
2
ture for 3 £ 48 h. The combined ethanol
2
extracts were suspended in H O (5 l) and
2
Ku, Kyoto, Japan), whereas CD spectra
were acquired on a JASCO-J-810 spec-
trometer (Jasco, Tokyo, Japan). IR spectra
were measured on a Bruker Vector-22
spectrophotometer (Bruker, Fallanden,
successively partitioned with petroleum
ether (60–908C), EtOAc, and n-butanol.
The EtOAc-soluble fraction (230 g) was
submitted to silica gel CC (1.3 kg, 200–
300 mesh, 10 £ 100 cm), eluting with a

7
28
Y.-P. Gao et al.
1 13
Table 1. H and C NMR spectroscopic data of compounds 1 and 2 (d in ppm, J in Hz).
a
1
b
2
Position
dC
dH
dC
dH
1
2
3
4
5
6
7
8
9
135.8, C
111.3, CH
146.8, C
144.5, C
114.5, CH
122.3, CH
47.8, CH
43.3, CH
64.7, CH
125.5, C
154.0, C
148.5, C
136.8, C
147.5, C
102.3, CH
31.7, CH
42.7, CH
73.0, CH
6.57, d (1.8)
6.84, d (7.8)
6.63 dd (7.8, 1.8)
3.95, d (9.0)
2.22, m
6.23, s
4.57 br s
2.32, m
3.88 dd (9.0, 5.6)
3.51 dd (9.0, 7.2)
2
4.46 dd (11.4, 2.4)
4
2
.21 dd (11.4, 2.4)
0
1
132.3, C
110.3, CH
145.1, C
143.8, C
115.3, CH
127.4, C
127.5, C
107.5, CH
147.9, C
138.2, C
146.8, C
124.0, C
0
2
6.65, s
6.45, s
0
3
0
4
0
5
0
6.34, s
6
0
7
32.6, CH2
2.97 dd (15.4, 9.6)
30.2, CH2
3.06 dd (16.8, 7.2)
2.83 d (16.8)
2.28, m
4.37 dd (12.0, 3.0)
3.72 dd (12.0, 5.6)
4.19, d (7.2)
3.19, dd (7.2, 9.0)
3.28, t (9.0)
3.45, m
2.90 dd (15.4, 3.6)
2.21, m
3.80, d (3.6)
0
8
38.3, CH
65.0, CH
35.5, CH
81.4, CH
0
9
2
2
0
0
0
0
0
0
0
0
0
0
1
2
3
4
5
112.4, C
161.7, C
117.7, CH
135.8, CH
119.2, CH
105.3, CH
75.1, CH
78.0, CH
71.3, CH
66.9, CH
6.98, d (8.4)
7.47 ddd (8.4, 8.4, 1.8)
6.86 t (8.4)
2
3.75, dd (10.2, 4.8)
3
.12, t (10.2)
0
0
0
0
6
7
3
3
5
5
129.6, CH
170.1, C
55.9
7.76 dd (8.4, 1.8)
-OMe
-OMe
3.76, s
3.87, s
60.1
56.5
56.5
61.9
3.78, s
3.71, s
3.40, s
3.91, s
0
-OMe
0
56.0
-OMe
a
1
13
3
Measured in CDCl at 600 MHz for H NMR, 150 MHz for C NMR.
1 13
b
3
In CD OD at 300 MHz for H NMR, 75 MHz for C NMR.
gradient Me CO (0–100%) in petroleum
2
(CHCl :MeOH, 100:1, 25:1, 15:1, 10:1,
3
ether, to afford eight fractions (A–H).
Fraction F (35 g) was submitted to silica
gel CC eluting with a gradient CHCl3/
5:1, 500 g, 200–300 mesh, 6 £ 100 cm)
and Sephadex LH-20 (2.5 £ 150 cm) elut-
ing with CHCl –MeOH (1:1). Fraction G
3
MeOH (CHCl :MeOH, 100:1, 25:1, 15:1,
3
(42 g) was subjected to silica gel CC
eluting with a gradient CHCl /acetone
1
0:1, 5:1, 400 g, 200–300 mesh, 6
100 cm), and the subfractions obtained
were further purified by Sephadex LH-20
3
£
(CHCl :Me CO, 50:1, 25:1, 10:1, 5:1,
3
2
500 g, 200–300 mesh, 6 £ 100 cm) to
yield four fractions (fractions G1–G4).
Fraction G1 (3 g) was submitted to a
Sephadex LH-20 CC (2.5 £ 150 cm) elut-
(
2.5 £ 150 cm) eluting with CHCl –
3
MeOH (1:1) and preparative silica gel
TLC to give compound 1 (3.0 mg).
Compound 2 (10.5 mg) was obtained
from fraction H (45 g) by silica gel CC
ing with CHCl –MeOH (1:1) to give
3
compound 3 (23.0 mg). Compounds 4

Journal of Asian Natural Products Research
729
(21.0 mg), 5 (30.5 mg), and 6 (19.0 mg)
were obtained from fraction G2 (20 g) by a
(CD OD, 75 MHz) spectroscopic data, see
3
Table 1; CD (MeOH, c ¼ 0.075): D1
1
99 nm
reversed phase C-18 CC (MeOH:H O,
2
26.23, D1
D1284 nm þ0.57; ESI-MS (positive and
2
þ12.24, D1
þ6.04,
215 nm
241 nm
3
preparative silica gel TLC (CHCl :MeOH,
0:70, 50:50, 70:30, 100% MeOH) and
þ
negative) m/z 573 [M þ Na] ; 549
3
10:1). Fraction G3 (10 g) was chromato-
graphed over a Sephadex LH-20 column
[M 2 H] ; HR-ESI-MS (positive) m/z
573.1692 [M þ Na]
þ
(calcd for
(
CHCl :MeOH, 1:1, 2.5 £ 150 cm), and
C H NaO , 573.1942).
27 34 12
3
finally purified by preparative silica gel
TLC (CHCl :MeOH, 10:1) to yield com-
3
pounds 7 (31.0 mg) and 8 (3 (23.0 mg).
Similarly, compound 9 (10.5 mg) was
isolated from fraction G4 (5 g) by repeated
References
[
1] R.C. Fang, Novon 9, 162 (1999).
CC over Sephadex LH-20 (CHCl :MeOH,
3
[2] X.J. Ma, L. Zhao, C.F. Du, B.Y. Shi, J.H.
Zheng, and X.Z. Chen, Chin. Tradit.
Herbal. Drugs 32, 945 (2001).
1
gel TLC (CHCl :MeOH, 10:1).
:1, 2.5 £ 150 cm) and preparative silica
3
[
3] B. Zhang, X.L. He, Y. Ding, and G.H. Du,
Eur. J. Pharmacol. 530, 166 (2006).
4] S.F. Fonseca, J.D.P. Campello, L.E.S.
Barata, and E.A. Ruveda, Phytochemistry
17, 499 (1978).
[
3
.3.1 9-Salicyl-(þ)-isolariciresinol (1)
17
Brown oil; ½aꢀ þ 10 (c ¼ 0.75, MeOH);
D
UV (MeOH) l
(
(log 1): 259 (0.98), 285
2.12) nm; IR (KBr) nmax: 3425, 2930,
[5] Z.Z. Zhang, D. Guo, C.L. Li, J.H. Zheng,
K. Koike, Z.H. Jia, and T. Nikaido,
Phytochemistry 51, 469 (1999).
[6] H. Utsunomiya, S. Okuno, K. Miyamoto,
M. Miyazawa, Japan patent JP
2011246419, (2011).
max
2
1
1732, 1635, 1500, 1489, 1384, 1045 cm
1
for H (CDCl , 600 MHz) and C NMR
;
13
3
(CDCl , 150 MHz) spectroscopic data, see
Table 1; ESI-MS (positive and negative)
3
[7] W. Kylne, R. Stevenson, and R.J. Swan,
J. Chem. Soc. (C) 9, 893 (1966).
þ
2
m/z 503 [M þ Na] ; 479 [M 2 H] , HR-
[
8] F. Abe and T. Yamauchi, Phytochemistry
27, 575 (1988).
ESI-MS (positive) m/z 503.1685
(calcd for C H NaO ,
27 28 8
þ
[
M þ Na]
[
9] Z.Z. Zhang, D. Guo, C.L. Li, J.H. Zheng,
K. Koike, Z.H. Jia, and T. Nikaido, Acta
Pharm. Sin. 34, 128 (1999).
5
03.1682).
[
[
10] A. Jutivikoonsuk, H.J. Zhang, G.T. Tan,
C.Y. Ma, N.V. Hung, N.M. Cuong,
N. Bunyapraphatsara, D.D. Soejarto,
and H.H.S. Fong, Phytochemistry 66,
3
.3.2 Gaultheroside G (2)
17
White solid; ½aꢀ þ 36 (c ¼ 1.5, MeOH);
D
UV (CHCl ) l
3
(log 1): 211 (1.68), 268
max
2
745 (2005).
(
0.27) nm; IR (KBr) nmax: 3443, 2923,
11] I. Kouno, Y. Yanagida, S. Shimono,
M. Shintomi, Y. Ito, and C.S. Yang,
Phytochemistry 32, 1573 (1993).
2
852, 1636, 1509, 1487, 1324 cm ; for
1
2
1
13
H (CD OD, 300 MHz) and C NMR
3