Lignans and neolignans from Sinocalamus affinis and their absolute configurations

Article abstract of DOI:10.1021/np200117y

Twenty-two new lignans and neolignans (1-22), together with 14 known analogues, have been isolated from an ethanolic extract of the stem (with skin removed) of Sinocalamus affinis. Their structures were elucidated by spectroscopic and chemical methods. On the basis of systematic NMR and circular dichroism (CD) data analysis, the validity of J_7,8 and Δδ_C8-C7 values to distinguish threo and erythro aryl glycerol units in different neolignans and the CD data [particularly the Rh ₂(OCOCF₃)₄-induced CD data (the E band)] to determine the absolute configurations at C-8 (C-7) of the aryl glycerol units are discussed. At a concentration of 10 μM, compounds 20 and 22 inhibited NO production in mouse peritoneal macrophages 84.2 ± 5.9% and 71.7 ± 1.0%, respectively. Compounds 19, 20, and 22 showed activity against serum deprivation induced PC12 cell damage by increasing the cell viability from 80.7 ± 2.8% to 91.6 ± 6.4%, 107.2 ± 8.0%, and 97.6 ± 8.5%, respectively. (Chemical Equation Presented).

Full text of DOI:10.1021/np200117y

ARTICLE
pubs.acs.org/jnp
Lignans and Neolignans from Sinocalamus affinis and Their Absolute
Configurations
Liang Xiong, Chenggeng Zhu,* Yanru Li, Ye Tian, Sheng Lin, Shaopeng Yuan, Jinfeng Hu, Qi Hou,
Naihong Chen, Yongchun Yang, and Jiangong Shi*
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College (Key Laboratory of Bioactive
Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education), Beijing 100050, People’s Republic of China
S Supporting Information
b
ABSTRACT: Twenty-two new lignans and neolignans
(1ꢀ22), together with 14 known analogues, have been isolated
from an ethanolic extract of the stem (with skin removed) of
Sinocalamus affinis. Their structures were elucidated by spectro-
scopic and chemical methods. On the basis of systematic NMR
and circular dichroism (CD) data analysis, the validity of J7,8 and
ΔδC8ꢀC7 values to distinguish threo and erythro aryl glycerol
units in different neolignans and the CD data [particularly the Rh2(OCOCF3)4-induced CD data (the E band)] to determine the
absolute configurations at C-8 (C-7) of the aryl glycerol units are discussed. At a concentration of 10 μM, compounds 20 and 22
inhibited NO production in mouse peritoneal macrophages 84.2 ( 5.9% and 71.7 ( 1.0%, respectively. Compounds 19, 20, and 22
showed activity against serum deprivation induced PC12 cell damage by increasing the cell viability from 80.7 ( 2.8% to 91.6 (
6.4%, 107.2 ( 8.0%, and 97.6 ( 8.5%, respectively.
inocalamus affinis (Rendle) McClure (Poaceae) is widely
distributed and cultivated in southwestern China.1 Different
’ RESULTS AND DISCUSSION
Compound 1 showed IR absorptions for OH (3246 cmꢀ1
)
S
and aromatic ring (1612 and 1493 cmꢀ1) groups. The NMR data
of 1 (Tables 1 and 2) indicated the presence of two pentasub-
stituted phenyl, four methoxy, three methylene (two oxygen-
bearing), and three methine groups. These data resembled those
of the co-occurring (þ)-lyoniresinol13 except that the reso-
nances for the 40-hydroxy-30,50-dimethoxyphenyl in (þ)-lyonir-
esinol were replaced by those attributable to a dimethoxy-dioxy-
phenyl. This combined with the molecular formula C22H26O8
(HRESIMS) suggested that 1 was an unusual 2,70-cyclolignane
containing an oxy-bridge between the dimethoxy-dioxy-phenyl
and C-9 or C-90. The suggestion was refined by 2D NMR data
analysis of 1 (Supporting Information, Figures S6ꢀS8). Particu-
larly, in the HMBC spectrum, correlations for H2-7/C-1, C-2,
C-6, C-8, C-80, and C-9; H-70/C-1, C-10, C-2, C-20, C-3, C-60,
C-8, C-80, and C-90; H-50/C-10, C-30, C-40, and C-60; OMe-20/C-
20; OMe-3/C-3; OMe-40/C-40; and OMe-5/C-5, together with
shifts of these resonances, proved that 1 had the basic structure of
30,4-dihydroxy-20,3,40,5-tetramethoxy-2,70-cyclolignane. HMBC
correlations for H2-9/C-60 revealed the oxy-bridge between C-60
and C-9. The remaining OH had to be positioned at C-90 to
match the molecular composition and shifts of H2-90 and C-90. In
the NOE difference spectrum of 1, irradiation of H-70 enhanced
OMe-20, OMe-3, H-80, and H-90a, while H-90b was enhanced
upon irradiation of H-8. These enhancements, together with the
parts of the plant, including the stem, leaves, and roots, are used in
traditional Chinese medicine.1 Slices of the stem (with skin
removed), named “ci zhu ru” in Chinese, are commonly used to
treat various diseases, such as cough and phlegm.1,2 However, no
chemical or pharmacological study of this remedy has been
reported.2,3 As part of a program to study the chemical diversity
of traditional Chinese medicines and their biological effects, an
ethanol extract of “ci zhu ru” has been investigated. We describe
herein the isolation, structure elucidation, and biological assays of
22 new lignans and neolignans (1ꢀ22) and 14 known analogues
from the EtOAc-soluble portion of the extract. On the basis of IUPC
recommendations for nomenclature of lignans and neolignans,4
compound 1 is categorized as an unusual 60,9-epoxy-2,70-cyclo-
lignane, 2and 3are 70,80,90-trinor- and 80,90-dinor-8,4-oxyneolignanes,
respectively, and 4 is a 80,90-dinor-4,800-oxy-8,30-sesquineolignane.
Though compounds with planar structures identical to sesquineo-
lignans (10ꢀ15),5ꢀ9 dineolignans (16ꢀ18),9,10 and flavonolignans
(19ꢀ22)11,12 were reported for more than 25 years, configurations
for these complex natural products were undetermined with contrary
and/or controversial data reported in the literature.5ꢀ12 Extensive
NMR and CD data analyses, in combination with chemical transfor-
mations, have led to assignments of configuration for 10ꢀ22. In
addition, by systematic comparison of the spectroscopic data, the
validity of J7,8 and ΔδC8ꢀC7 values to distinguish threo and erythro
arylglycerol units in the different series of neolignans and the CD data
[particularly, the Rh2(OCOCF3)4-induced CD data (the E band)] to
determine the absolute configurations at C-7 of the aryl glycerol units
are discussed.
0
0
coupling constant of J7 ,8 (≈0 Hz), indicated that the torsion
Received: February 8, 2011
Published: April 06, 2011
r
Copyright
2011 American Chemical Society and
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American Society of Pharmacognosy
|

Journal of Natural Products
ARTICLE
angle between H-70 and H-80 was about 90° and revealed that
H-80 was trans-oriented to H-70 and H-8. The CD spectrum of 1
displayed a negative Cotton effect at 284 nm (Δε ꢀ1.03)
1
corresponding to the Lb band of the benzene chromophores.
On the basis of the benzene sector and the benzene chirality rules
for chiral tetralin derivatives,14 the 70S configuration was assigned
for 1 (Supporting Information, Figure S10). Therefore, com-
pound 1 was (þ)-(70S,8S,80S)-30,4-dihydroxy-20,3,40,5-tetra-
methoxy-60,9-epoxy-2,70-cyclolignan-90-ol.
Compound 2, C18H22O8 (HRESIMS), showed IR absorptions
for OH (3405 cmꢀ1) and aromatic ring (1603 and 1512 cmꢀ1
)
groups. The NMR data (Tables 1 and 2) indicated that there were
both guaiacylglycerol-8-yl and 30,50-dimethoxy-10,40-dioxyphenyl
groups in 2. The chemical shifts of the oxymethines and the
coupling constant (J7,8 = 7.5 Hz), together with the molecular
composition, suggested that 2 was 7,8-threo-10,4-dihydroxy-3,30,50-
trimethoxy-70,80,90-trinor-8,40-oxyneoligna-7,9-diol.15,16 This was
confirmed by 2D NMR data analysis of 2 (Supporting Informa-
tion, Figures S16ꢀS18). The HMBC correlations from H-7 to
C-1, C-2, C-6, C-8, and C-9, from H-20/60 to C-10, C-30/50, and
C-40, and from OMe-30/50 to C-30/50, together with their shifts,
verified the location of the substitutents and the 8,40-oxy linkage in
2. A positive Cotton effect at 237 nm in the CD spectrum
suggested the 8S configuration for 2.15ꢀ17 On the basis of the
bulkiness rule for secondary alcohols,18 a positive Cotton effect at
351 nm (the E band) in the Rh2(OCOCF3)4-induced CD
spectrum (Supporting Information, Figure S19) indicated the 7S
Table 1. H NMR Data (δ) for Compounds 1ꢀ3, 3a, and 5ꢀ9a
1
no.
1
2
3
3ab
5
6c
7
8
9
2
7.05 d (2.0)
6.77 d (8.0)
6.96 brs
6.95 brs
6.75 brs
7.03 d (1.5)
6.80 d (8.0)
7.34 brs
6.76 brs
6.69 brs
5
6.69 d (8.0) 6.68 d (8.4)
6
6.40 s
6.90 dd (8.0, 2.0) 6.82 d (8.0) 6.80 d (8.4) 6.75 brs
6.88 dd (8.0, 1.5) 7.34 brs
5.56 d (6.5)
6.76 brs
6.69 brs
7a
3.02 dd
4.94 d (7.5)
4.94 d (7.0) 4.94 d (6.0) 5.59 d (6.5)
4.92 d (8.5) 4.70 d (4.2)
(17.0, 7.5)
2.79 d (17.0)
2.17 m
7b
8
3.74 m
4.05 m
4.21 m
3.51 m
3.91 m
3.53 m
3.88 m
4.21 m
4.18 m
2.27 m
3.72 m
3.09 m
4.24 m
9a
4.34 dd
3.59 dd
3.70 dd
(12.0, 3.5)
3.28
3.72 dd
(12.0, 3.0)
(12.5, 3.5)
(12.0, 4.2)
3.33 dd
9b
3.71 d (12.0) 3.22 dd
(12.5, 2.5)
3.85 m
3.82 m
4.14 m
6.67 brs
6.67 brs
3.64 m
6.75 brs
6.75 brs
3.85 m
6.67 brs
6.67 brs
(12.0, 2.5)
7.32 brs
(12.0, 3.6)
7.28 brs
20
50
60
6.21 brs
6.96 brs
6.99 brs
6.19 s
6.21 brs
7.32 brs
7.28 brs
6.95 brs
6.97 brs
70
80
90a
4.51 brs
2.09 m
6.52 d (16.0)
6.53 d (16.0)
4.59 d (8.5) 4.90 d (8.5) 4.66 d (4.2)
6.24 dt (16.0, 5.5) 6.17 dt (16.0, 6.0) 2.58 m
2.27 m
3.72 m
3.09 m
4.24 m
3.56 dd
4.19 (5.5)
4.05 d (6.0)
3.64 dd
(11.0, 8.0)
3.48 dd
(11.5, 4.5)
3.59 dd
90b
3.64 m
3.85 m
(11.0, 7.5)
(11.5, 5.0)
OMe-3/5 3.31 s/3.74 s 3.82 s/
3.77 s/
3.77 s/
3.82 s/3.82 s
3.70 s
3.81 s/
/3.86 s
3.86 s/3.86 s 3.82 s/3.82 s 3.81 s/3.81 s
3.71 s 3.69 s
OMe-4
OMe-20/40 3.84 s/3.67 s
OMe-30/50
3.81 s/3.81 s
3.82 s/3.82 s 3.83 s/3.83 s /3.88 s
3.80 s/3.80 s 3.82 s/3.82 s 3.81 s/3.81 s
a Data were measured in MeOH-d4 at 500 MHz for 1, 3, and 7 and at 600 MHz for 3a and in Me2CO-d6 for 2, 5, 6, 8, 9 at 500 or 600 MHz. Coupling
constants (J) in Hz are given in parentheses. The assignments were based on 1Hꢀ H COSY, HSQC, and HMBC. b Data for COOMe in 3a: δ 3.83 s.
1
c Data for OEt in 6: δ 3.47 q (7.0), 1.15 t (7.0).
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ARTICLE
Table 2. 13C NMR Data (δ) for Compounds 1ꢀ3, 3a, and 5ꢀ9a
no.
1
2
3
3ab
5
6c
7
8
9
1
127.6
133.8
133.4
133.5
138.5
132.2
108.3
146.2
145.1
113.5
117.4
86.4
128.6
140.0
138.5
2
124.1
147.5
138.2
148.6
107.4
30.0
111.6
147.9
146.8
115.2
120.8
74.1
111.8
148.8
147.2
115.9
121.0
74.6
111.7
148.7
147.2
115.8
120.8
74.4
104.0
154.4
138.5
154.4
104.0
88.3
107.8
149.2
142.9
149.2
107.8
200.3
50.2
104.5
154.3
138.3d
154.3
104.5
83.8
104.1
154.4
138.6
154.4
104.1
86.6
3
4
5
6
7
8
35.4
90.0
89.1
88.7
54.8
52.6
56.8
55.3
9
81.6
61.1
61.8
62.0
64.5
62.4
71.6
62.6
72.4
10
20
30
40
50
60
70
80
90
125.7
146.9
136.8
147.9
102.3
154.0
31.4
155.2
94.0
123.8
108.1
153.6
139.7
153.6
108.1
156.0d
126.6
107.9
154.1
141.9
154.1
107.9
168.0
132.0
116.0
130.1
148.8
145.1
111.7
130.3
128.4
63.3
129.4
114.1
128.2
147.0
143.0
109.5
130.4
122.8
69.5
132.9
105.3
149.2
136.3
149.2
105.3
85.4
134.4
104.8
148.6
137.0d
148.6
104.8
84.1
133.1
104.5
148.7
136.2
148.7
104.5
86.7
154.4
130.0
154.4
94.0
45.2
55.1
56.8
55.4
65.3
61.4
62.7
72.5
OMe-3/5
60.0/56.5
56.2/
56.4/
56.4/
56.4/56.4
60.4
54.1/
56.9/56.9
56.4/56.4
60.5
56.4/56.4
60.4
OMe-4
OMe-20/40
OMe-30/50
ΔδC8ꢀC7
61.7/56.5
56.4/56.4
15.9
56.6/56.6
14.5
56.8/56.8
14.3
/56.3
/54.2
56.8/56.8
56.7/56.7
56.5/56.5
a Data were measured in MeOH-d4 for 1, 3, and 7 at 500 MHz and for 3a at 600 MHz and in Me2CO-d6 for 2, 5, 6, 8, and 9 at 500 MHz. The assignments
were based on 1Hꢀ H COSY, HSQC, and HMBC experiments. b Data for COOMe in 3a: δ 52.8. c Data for OEt in 6: δ 63.6, 13.4. d Data were obtained
1
from the HMBC spectrum.
configuration for 2, which was in agreement with that defined
by the 7,8-threo and 8S configurations assigned above. Thus, 2
was (þ)-(7S,8S)-10,4-dihydroxy-3,30,50-trimethoxy-70,80,90-trinor-
8,40-oxyneoligna-7,9-diol.
aromatic ring (1592 and 1514 cmꢀ1) groups. The NMR data
of 4 (Tables 3 and 4) indicated the presence of a symmetric
3,4,5-trisubstituted phenyl, an asymmetric 30,40,50-trisubstituted
phenyl, a 300,400-disubstituted phenyl, and aldehyde groups. Also
evident were four aromatic OCH3, two oxymethylene, and four
methine (three oxygenated) groups. These data suggested that 4
was a dinorsesquineolignane.6b,10 In the HMBC spectrum of 4,
correlations for H-2 (H-6)/C-1, C-4, and C-7; H-7/C-1, C-2,
C-6, C-8, C-9, and C-40; H-8/C-1, C-7, C-9, C-30, and C-40;
H-20/C-40, C-60, C-70, and C-8; OMe-50/C-50; and OMe-3 (OMe-
5)/C-3 (C-5) revealed the presence of a 4-substituted 3,5,50-
trimethoxy-40,7-epoxy-8,30-neolignan-9-ol-70-al moiety. In addi-
tion, HMBC correlations for H-200 and H-600/C-400 and C-700;
H-500/C-100 and C-300; H-700/C-100, C-200, C-600, C-800, and C-900;
and OMe-300/C-300 indicated the presence of a guaiacylglycerol
unit in 4. Although no HMBC correlation for H-800/C-4 was
observed, the connection between C-800 and C-4 was indicated
by the shifts for H-800 (δH 4.19) and C-800 (δC 87.8) and C-4 (δC
136.4) and C-3/5 (δC 154.4).10,16,19 In the NOE difference
spectrum of 4, H-2 and/or H-6 were enhanced when H-8 was
irradiated, and irradiation of H-7 gave an enhancement of H2-9.
These enhancements combined with the coupling constant
(J7,8 = 6.5 Hz)20 indicated the 7,8-trans configuration for 4. The
700,800-erythro configuration was deduced by the coupling constant
Compound 3 (C19H22O9) had an additional CO unit. The
NMR spectra of 3 (Supporting Information, Figures S23ꢀS25)
resembled those of 2. However, the resonances for H-20/60 and
C-20/60 of 3 were broadened, compared with those of 2, and
deshielded significantly by ΔδH 1.11 and ΔδC 14.1 ppm, respec-
tively. This suggested that OH-10 in 2 was replaced by COOH-10
in 3 to match the molecular composition, although the 13C NMR
spectrum displayed two fewer carbon resonances (C-10 and C-70)
than those expected from the molecular formula. The presence of
COOH-10 was supported by the 2D NMR data analysis of 3 that
amended the 1D NMR data assignments (Tables 1 and 2). This
was confirmed by methylation of 3 with CH3I that produced 3a.
The NMR spectra of 3a displayed resonances (Tables 1 and 2 and
Supporting Information, Figures S31ꢀS33) corresponding to
COOMe. The 1H NMR coupling constants of 3 (J7,8 = 7.0 Hz)
and 3a (J7,8 = 6.0 Hz) and positive Cotton effects in the CD
spectra of 3 (258 nm) and 3a (262 nm) suggested the 7S,8S
configuration (Supporting Information, Figures S29 and S34).
This was supported by positive Cotton effects in the Rh2-
(OCOCF3)4-induced CD spectra of 3 (359 nm) and 3a
(356 nm) (Supporting Information, Figures S29 and S34). There-
fore, compound 3 was deduced to be (þ)-(7S,8S)-4-hydroxy-
3,30,50-trimethoxy- 80,90-dinor-8,40-oxyneoligna-7,9-diol-70-oic acid.
Compound 4 (C29H32O11) showed IR absorption bands
for OH (3429 cmꢀ1), conjugated carbonyl (1680 cmꢀ1), and
J7 ,8 (2.0 Hz).16 In the CD spectrum, a negative Cotton effect at
00 00
295 nm (Δε ꢀ0.15) indicated that 4 had a 7R,8S configuration on
the basis of the reversed helicity rule of the 1Lb band CD for the
7-methoxy-2,3-dihydrobenzo[b]furan chromophore21 (Supporting
Information, Figure S45). The 800R configuration was proposed by a
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Table 4. 13C NMR Data (δ) for Compounds 4 and 10ꢀ15a
4
10
11
12
13
14
15
no.
Me2CO-d6 Me2CO-d6 CDCl3 Me2CO-d6 CDCl3 Me2CO-d6 CDCl3 Me2CO-d6 CDCl3 Me2CO-d6 CDCl3 Me2CO-d6 CDCl3
1
138.1
104.3
154.4
136.4
154.4
104.3
89.6
139.0
104.1
154.2
135.7
154.2
104.1
86.6
137.8
102.8
153.5
134.3
153.5
102.8
86.0
139.2
104.0
153.8
136.1
153.8
104.0
86.6
137.9
102.7
153.1
134.6
153.1
102.7
85.9
139.1
104.0
154.2
135.7
154.2
104.0
86.7
137.7
102.7
153.3
134.2
153.3
102.7
85.9
139.2
103.9
153.8
136.0
153.8
103.9
86.7
137.8
102.7
153.1
134.4
153.1
102.7
86.0
139.1
104.8
154.1
135.8
154.1
104.8
86.7
137.8
102.9
153.5
134.4
153.5
102.9
86.0
139.2
104.0
153.8
136.1
153.8
104.0
86.7
137.9
102.7
153.5
134.4
153.5
102.7
86.0
2
3
4
5
6
7
8
54.0
55.1
54.1
55.1
54.0
55.2
54.2
55.2
54.4
55.2
54.4
55.2
54.3
9
64.2
72.5
72.2
72.5
72.1
72.6
71.9
72.6
72.0
72.6
72.1
72.6
72.0
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
800
900
132.6
121.3
131.0
154.7
145.8
113.5
190.9
134.1
110.9
148.0
146.9
115.5
120.0
86.5
132.7
108.6
146.6
145.3
114.3
118.9
85.7
134.1
110.6
148.3
146.7
115.2
119.6
86.5
132.7
108.6
146.7
145.3
114.2
118.9
85.7
133.7
104.4
148.7
136.2
148.7
104.4
86.6
131.8
102.7
147.2
134.4
147.2
102.7
85.8
133.7
104.4
148.7
136.2
148.7
104.4
86.5
131.9
102.7
147.2
134.6
147.2
102.7
85.8
133.1
104.4
148.7
136.2
148.7
104.4
86.6
131.9
102.8
147.2
134.4
147.2
102.8
86.0
133.1
104.5
148.7
136.2
148.7
104.5
86.5
131.9
102.7
147.2
134.6
147.2
102.7
85.8
55.4
54.5
55.5
54.5
55.4
54.3
55.4
54.5
55.4
54.5
55.4
54.5
72.3
71.5
72.3
71.5
72.4
71.6
72.4
71.7
72.4
71.7
72.4
71.7
133.7
110.9
147.9
146.4
115.2
120.0
73.4
134.0
110.6
148.3
146.4
115.2
119.6
73.4
131.3
108.3
146.7
144.9
114.1
118.7
72.5
133.7
111.3
147.9
146.9
115.5
120.6
73.9
131.9
109.7
146.4
145.4
114.3
120.4
74.1
133.1
110.9
148.0
146.4
115.2
120.0
73.3
131.2
108.5
146.6
144.8
114.2
118.7
72.4
133.0
111.3
147.9
146.7
115.2
120.6
73.9
131.9
109.8
146.5
145.4
114.3
120.3
74.0
133.0
104.1
148.4
133.1
148.4
104.1
73.6
130.4
102.6
147.1
134.0
147.1
102.6
72.7
132.7
105.3
148.3
136.0
148.3
105.3
74.0
131.0
104.0
147.0
134.3
147.0
104.0
74.3
87.8
87.9
87.1
89.6
89.1
87.8
86.9
89.6
89.0
87.9
87.2
89.3
89.1
61.0
61.0
60.6
61.4
60.5
60.9
60.4
61.4
60.5
61.0
60.6
61.5
60.5
OMe-3/5
56.6
56.6
56.2
56.6
56.2
56.6
56.3
56.6
56.5
56.8
56.4
56.6
56.4
OMe-30/50
OMe-300/500
56.4
56.2
56.0
56.2
56.0
56.6
56.2
56.6
56.4
56.8
56.4
56.6
56.3
56.2
56.2
56.0
56.2
56.0
56.2
55.9
56.2
56.0
56.6
56.3
56.5
56.2
00
00
ΔδC8
14.4
14.5
14.6
15.7
15.0
14.5
14.5
15.7
1
15.0
14.3
14.5
15.3
14.8
ꢀC7
a Data were measured for 4 and 10ꢀ15 at 125 MHz. The assignments were based on 1Hꢀ H COSY, HSQC, and HMBC experiments.
negative Cotton effect at 235 nm.15ꢀ17 The 700S configuration defined
by the 700,800-erythro was supported by a positive Cotton effectat347nm
(the E band) in the Rh2(OCOCF3)4-induced CD spectrum of 418
(Supporting Information, Figure S45). Therefore, compound 4 was
(ꢀ)-(7R,8S,700S,800R)-3,300,5,50- tetramethoxy-400-hydroxy-40,7-
epoxy-80,90-dinor-4,800-oxy-8,30-sesquineoligna-700,9,900-triol-70-al.
Compound 5 exhibited spectroscopic data (Tables 1 and 2 and
Experimental Section) almost identical to those of woorenogenin,22
but with opposite Cotton effects. Comprehensive analysis of the
2D NMR and NOE difference spectra proved that 5 had the same
planar structure and relative configuration as woorenogenin. On
the basis of the reversed helicity rule of the 1Lb band CD for the
7-methoxy-2,3-dihydrobenzo[b]furan chromophore,21 a nega-
tive Cotton effect at 272 nm in the CD spectrum of 5 indicated
that it had a 7R,8S configuration (Supporting Information,
Figure S54), and this was supported by the negative optical
rotation (the reported optical rotation of woorenogenin was
ambiguous).23 Thus, compound 5 was (ꢀ)-(7R,8S,70E)-3,4,5,50-
tetramethoxy-40,7-epoxy-8,30-neolign-70-ene-9,90-diol.
resonances of the 3,4,5-trimethoxyphenyl group in 5 were
replaced by those attributed to 3-methoxy-4-hydroxyphenyl
and ethoxy units in 6 (Tables 1 and 2). In addition, the resonance
for C-90 of 6 was deshielded significantly as compared with that of
5. This implied that OH-90 in 5 was substituted by OEt-90 in 6,
which was confirmed by a correlation for H2-100/C-90 in the
HMBC spectrum of 6 (Supporting Information, Figure S62). The
optical rotation and CD data of 6 were opposite of those of 5,
indicating a 7S,8R configuration for 6.21 Accordingly, compound 6
was determined as (þ)-(7S,8R,70E)-4-hydroxy-3,50-dimethoxy-
40,7-epoxy-8,30-neolign-70-ene-9,90-diol 90-ethyl ether. The ethyl
group in 6 could be an artifact formed during isolation, although
the de-ethyl precursor of 6 was not obtained in this study.
Compound 7, C22H26O9, showed IR absorptions for OH
(3473 cmꢀ1), conjugated carbonyl (1661 cmꢀ1), and aromatic
ring (1611 and 1518 cmꢀ1) groups. The NMR data (Tables 1
and 2) were similar to those of wikstrone15 except for substitu-
tion of the resonances for the 40-hydroxy-30,50-dimethoxyphenyl
moiety in 7 by those for the 40-hydroxy-30-methoxyphenyl unit in
wikstrone. This was confirmed by 2D NMR data analysis
(Supporting Information, Figures S71ꢀS73). The shifts and
Compound 6 (C22H26O6) had UV, IR, and NMR spectro-
scopic features similar to those of 5, except that the NMR
1192
dx.doi.org/10.1021/np200117y |J. Nat. Prod. 2011, 74, 1188–1200

Journal of Natural Products
ARTICLE
coupling constants for H-70 and H-80 of 7, similar to those of
wikstrone, indicated that H-80 was oriented opposite H-70 and
H-8. This was verified by enhancements of H-2/H-6 and H-20/
H-60 (overlapped each pair) when H-80 was irradiated in the
NOE difference spectrum of 7. In the CD spectrum of 7, Cotton
effects (negative at 324 nm and positive at 286 nm) arising from
the exciton coupling of the benzoyl and benzene chromphores
(Supporting Information, Figure S75) suggested the 70S,8S,80R
configuration.15 Thus, compound 7 was determined to be (ꢀ)-
(70S,8S,80R)-4,40-dihydroxy-3,30,5,50-tetramethoxy-70,9-epoxylignan-
90-ol-7-one.
demonstrated that they had the same relative configuration. The
relative configuration of 10 was supported by the 1H NMR coupling
0
0
00 00
constants J7,8, J7 8 , and J7 ,8 in the spectrum of the acetonide
derivative (10a) (Supporting Information, Figure S108 and Table
S1). Alkaline hydrolysis of 10 liberated a product having the
spectroscopic data including [R]D identical to (ꢀ)-medioresinol.
Comparing the CD data of (ꢀ)-medioresinol with those of 10 and
10a (Supporting Information, Figures S106, S110, and S247), a
negative 1Lb Cotton effect at 281 nm in the CD spectra of 10 and
10a supported the 7R,70R,8S,80S configuration.28,30 In addition, a
positive Cotton effect at 239 nm indicated the 800S configuration for
10 and 10a.15ꢀ17 The 700R configuration defined by the 700,800-
erythro was supported by a negative Cotton effect at 353 nm (the E
band) in the Rh2(OCOCF3)4-induced CD spectrum of 10 since the
E band was absent in the Rh2(OCOCF3)4-induced CD of 10a and
(ꢀ)-medioresinol (Supporting Information, Figure S106). Thus,
10 was (ꢀ)-(7R,70R,700R,8S,80S,800S)-40,400-dihydroxy-3,30,300,5-
tetramethoxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineo-
lignan-700,900-diol.
The spectroscopic data of 11 (Tables 3 and 4 and Experi-
mental Section) were consistent with hedyotol D.5a,c,d However,
the configuration and [R]D values (positive5a and negative5c,d) of
hedyotol D were ambiguous. Using the same methods as
described for 10 (Supporting Information, Figures S122ꢀ126
and Table S1), the 7R,70R,700S,8S,80S,800S configuration of 11 was
elucidated. Particularly, in the Rh2(OCOCF3)4-induced CD
spectrum, a positive Cotton effect at 348 nm opposite that of
10 (Supporting Information, Figure S122) supported the 700S
configuration for 11.
The spectroscopic data of 12 (Tables 3 and 4 and Experi-
mental Section) were almost identical to those of buddlenol C,
which was reported to have controversial configuration.6a,b,7 The
7R,70R,700R,8S,80S,800S configuration of 12 was verified by the
NMR data of the acetonide product (12a) (Supporting Informa-
tion, Figures S140ꢀ142 and Table S1) as well as by alkaline
hydrolysis producing (ꢀ)-syringaresinol and the CD data of 12
and 12a including the Rh2(OCOCF3)4-induced CD data of 12
(negative at 351 nm) (Supporting Information, Figure S138).
Compound 13 was the 700,800-threo isomer of 12 possessing a
700S configuration, as indicated by the spectroscopic data (Tables 3
and 4 and Experimental Section) and confirmed by the same
procedures as described above (Supporting Information, Figures
S153ꢀ155 and Table S1). 700,800-threo-Buddlenol C was reported
to have UV, IR, MS, and NMR data identical to 13, but with
ambiguous configuration6a,b,7 and [R]D value (positive7f).
The spectroscopic data of 14 (Tables 3 and 4 and Experimental
Section) were in agreement with those of buddlenol D, which was
assigned ambiguous configuration.6a,7c,7e,8 Using the same meth-
ods as above (Supporting Information, Figures S167ꢀS171 and
Table S1), compound 14 was (ꢀ)-(7R,70R,700R,8S,80S,800S)-40,400-
dihydroxy-3,30,300,5,50,500-hexamethoxy-7,90:70,9-diepoxy-4,800-oxy-
8,80-sesquineolignan-700,900-diol.
Differences of the spectroscopic data between 15 and 14
(Tables 3 and 4 and Experimental Section) were similar to those
between 11 and 10 and between 13 and 12. This demonstrated
that 15 was the 700,800-threo isomer of 14. The 7R,70R,700S,8S,
80S,800S configuration of 15 was substantiated also as described
above (Supporting Information, Figures S179ꢀS183 and Table S1).
Compound 16 had the molecular formula C42H50O16
(HRESIMS), and the NMR data (Table 5) resembled those of
hedyotisol A, having conflicting configuration and [R]D values
(optical inactive7h,9 and negative10). The 700,800:7000,8000-di-erythro
Compound 8 had the molecular formula C23H30O9, and the
NMR data of 8 (Tables 1 and 2) were similar to those of icariol
A2.24 However, resonances for an additional OCH3 were ob-
served in the spectra of 8. This indicated replacement of OH-4 in
icariol A2 by OMe-4 in 8, which was proved by 2D NMR analysis.
Detailed explanation of the HMBC data (Supporting Informa-
tion, Figure S83) amended the assignment of the shifts for C-4
and C-40 that were not observed in the 13C NMR spectrum of 8
due to limitation of the sample amount available. The 1H NMR
shifts and coupling constants for H-7, H-70, H-8, and H-80 of 8
indicated the trans-orientation between each pair of the vicinal
protons.24 The CD spectrum displayed a typical coupled Cotton
effect, positive at 243 nm (Δε þ10.9) and negative at 207 nm
(Δε ꢀ16.6), indicating exciton coupling between the πfπ*
transition of the phenyl chromophores (Supporting Information,
Figure S84). The positive chirality revealed the 7R,70R,8S,80S
configuration for 8,25 which was supported by the positive optical
rotation {[R]20 þ25.5 (c 0.04, MeOH)}.24b,25 Therefore,
D
compound 8 was determined to be (þ)-(7R,70R,8S,80S)-40-
hydroxy-3,30,4,5,50-pentamethoxy-7,70-epoxy lignan-9,90-diol.
Compound 9, C23H28O8, displayed spectroscopic data similar
to those of (ꢀ)-syringaresinol.26 However, the NMR spectra in
Me2CO-d6 indicated partial separation of resonances for the two
aryl groups and the presence of a phenolic OH and five OCH3
groups in 9. This suggested that 9 was 40-hydroxy-3,30,4,5,50-
pentamethoxy-7,90:70,9-diepoxylignane. 2D NMR data analysis
of 9 (Supporting Information, Figures S91ꢀS93) provided
unambiguous assignments. The coupling constants of J7,8 and
0
0
0
0
J7 ,8 (4.2 Hz) and the shifts of H-7/H-7 , H-8/H-8 , and C-8/C-
80 indicated that the aryl groups were pseudoequatorial and cis-
oriented with H-8 and H-80 in 9.20,27 The CD data (negative at
274, 239, and 214 nm) and specific rotation {[R]20D ꢀ45.8 (c
0.03, MeOH)} of 9 were consistent with those of (ꢀ)-
syringaresinol26 (Supporting Information, Figure S247), but
opposite those of (þ)-syringaresinol.28,29 Therefore, compound
9 was (ꢀ)-(7R,70R,8S,80S)-40-hydroxy-3,30,4,5,50-pentamethoxy-7,
90:70,9-diepoxylignane.
Compound 10 had the molecular formula C31H36O11, and
comparison of the NMR data between 10 (Tables 3 and 4) and
medioresinol29 indicated that they differed in the presence of
resonances attributable to an additional 400-hydroxy-300-methoxy-
phenylglycerol-800-yl moiety in 10. The coupling constant for J7 ,8
00 00
(3.0 Hz) indicated an erythro configuration for the aryl glycerol-800-
yloxy moiety,9 and shifts of resonances for C-800 (87.9) and C-3/5
(154.2)10 in Me2CO-d6 revealed that the aryl glycerol-800-yloxy was
located at C-4. This suggested that 10 had the same planar structure
as hedyotol C5 and/or buddlenol E.6 However, hedyotol C, with
configuration undetermined, was reported to have contrary optical
rotations (positive5a,b and negative5c,d), and buddlenol E was
reported as a mixture of 700,800-erythro and threo isomers.6a,c
Comparison of the NMR data between 10 and hedyotol C
1193
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Journal of Natural Products
ARTICLE
Table 5. NMR Data (δ) for Compounds 16ꢀ18a
16
17
18
16
17
18
no.
δH
δC
δH
δC
δH
δC
no.
δH
δC
δH
δC
δH
δC
1
2
3
4
5
6
7
8
9a
9b
10
20
30
40
50
60
70
80
90a
90b
138.9
104.0 6.76 brs
154.1
135.6
154.1
139.1
104.0 6.76 brs
153.9
136.1
153.9
139.0 100
104.1 200
154.2 300
135.5 400
154.2 500
104.1 600
133.7
110.9 7.03 d (1.5)
147.9
146.4
115.2 6.75 d (8.5)
133.7
111.3 7.03 brs
147.9
133.7
110.9
147.9
146.5
6.76 brs
7.03 d (1.5)
146.7
6.76 d (8.4)
115.2 6.75 d (8.0) 115.2
6.76 brs
104.0 6.76 brs
104.0 6.76 brs
6.82 dd (8.4, 1.5) 120.0 6.89 dd (8.5, 1.5) 120.6 6.82 d (8.0) 120.0
4.74 d (3.3) 86.4 4.74 d (3.0) 86.5 4.74 d (3.0) 86.4 700
4.97 brs
4.16 m
3.85 m
3.45 m
73.3 4.98 d (7.0)
87.7 3.94 m
60.9 3.64 m
3.31 m
133.7
110.9 7.03 d (1.5)
147.9
73.9 4.97 brs
89.6 4.15 m
3.84 m
61.4 3.45 m
133.7
111.3 7.03 brs
147.9
146.7
73.4
87.8
61.0
3.12 m
4.28 m
3.91 m
55.3 3.12 m
72.6 4.28 m
3.89 m
138.9
104.0 6.76 brs
154.1
135.6
154.1
104.0 6.76 brs
55.4 3.12 m
72.6 4.28 m
3.91 m
139.1
104.0 6.76 brs
153.9
136.1
153.9
104.0 6.76 brs
55.3 800
72.6 900a
900b
139.1 1000
104.0 2000
153.9 3000
135.7 4000
153.9 5000
104.0 6000
133.8
111.3
148.0
146.7
6.76 brs
7.03 d (1.5)
146.4
115.2 6.75 d (8.5)
6.76 d (8.4)
115.2 6.75 d (8.0) 115.2
6.76 brs
6.82 dd (8.4, 1.5) 120.0 6.89 dd (8.5, 1.5) 120.6 6.89 d (8.0) 120.6
4.74 d (3.3) 86.4 4.74 d (3.0) 86.5 4.74 d (3.0) 86.5 7000
4.97 brs
4.16 m
3.85 m
3.45 m
73.3 4.98 d (7.0)
87.7 3.94 m
60.9 3.64 m
3.31 m
56.2 3.80 s
14.4
73.9 4.97 (7.0)
89.6 3.94 m
61.4 3.64 m
3.31 m
56.2 3.80 s
15.7
73.9
89.6
61.4
3.12 m
4.28 m
3.91 m
3.85s
55.3 3.12 m
72.6 4.28 m
3.89 m
56.6 3.89 s
56.6 3.89 s
56.2 3.80 s
55.4 3.12 m
72.6 4.28 m
3.89 m
56.6 3.86 s
56.6 3.89 s
56.2 3.82 s
55.3 8000
72.6 9000
9000
a
b
OMe-3/5 0
56.6 OMe-3000/5000 3.81 s
56.2
14.4
15.7
OMe-30/5
3.85s
56.6 ΔδC8
56.2 ΔδC8
00
000
00
ꢀC7
OMe-300/500 3.81 s
14.4
15.7
000
ꢀC7
a 1H NMR data were measured in Me2CO-d6 at 300 MHz for 16 and at 500 MHz for 17 and 18, respectively. Proton coupling constants (J) in Hz are
given in parentheses. 13C NMR data were measured in Me2CO-d6 at 125 MHz for 16ꢀ18. The assignments were based on 1Hꢀ H COSY, HSQC, and
1
HMBC experiments.
configuration of 16 was indicated by the00coupling constant of
Rh2(OCOCF3)4-induced CD of 18 with 16 and 17. The Rh2-
(OCOCF3)4-induced CD spectrum of 18 gave a diminished
positive Cotton effect with the intensity representing deduction
of the half-intensity of the Cotton effect for the 700R,7000R-isomer
(16) from that for the 700S,7000S-isomer (17). Accordingly, 18 was
(þ)-(7R,70R,700R,7000S,8S,80S,800S,8000S)-400,4000-dihydroxy-3,30,300,
3000,5,50-hexamethoxy-7,90:70,9-diepoxy-4,800:40,8000-bisoxy-8,80-di-
neolignan-700,7000,900,9000-tetraol. Hedyotisol B was reported
to have spectroscopic data similar to those of 18; how-
ever, its configuration had not been determined (optical
inactive9a,b,d,f).
(≈0 Hz) and the shifts of H-8 /8000, H2-900/9000, and
00 00
J7 ,8 /J7
000,8000
C-800/8000. Alkaline hydrolysis of 16 generated (ꢀ)-syringaresi-
nol, suggesting the 7R,70R,8S,80S configuration. This was sup-
ported by a negative 1Lb Cotton effect at 287 nm28,30 in the CD
spectrum of 16. In addition, the 800S,8000S configuration was
proposed by a positive Cotton effect at 234 nm15ꢀ17 and
supported by a negative Cotton effect at 351 nm (the E band)
in the Rh2(OCOCF3)4-induced CD spectrum of 16 (Supporting
Information, Figure S190).
The spectroscopic data of 17 (Table 5 and Experimental Section)
indicated that it was the 700,800:7000,8000-di-threo isomer of 16.
Application of the same methods as described for 16 resulted in
the assignment of a 7R,70R,700S,7000S,8S,80S,800S,8000S configuration
for 17. Particularly, in the Rh2(OCOCF3)4-induced CD spectrum, a
positive Cotton effect at 350 nm (Supporting Information, Figure
S197) substantiated the 700R,7000R configuration for 17. It was
reported that hedyotisol C had MS and NMR data identical to
17, but it also had ambiguous configuration (optically inactive9a,d,f).
Compound 18 was another isomer of 16, as indicated by the
spectroscopic data (Table 5 and Experimental Section). How-
ever, the NMR resonances for the two disubstituted aryl glycerol
units were partially separated. Analysis of the 1D and 2D NMR
data of 18 indicated that the resonances for one aryl glycerol unit
[H-800, H2-900, and C-800] were identical to those of 10, 12, 14,
and 16, whereas the resonances for another aryl glycerol unit [H-
8000, H2-9000, and C-8000] were identical with those of 11, 13, 15, and
17. These data indicated that 18 was the 700,800-erythro-7000,8000-
threo stereoisomer of 16 and 17. In the CD spectrum of 18, a
positive Cotton effect at 235 nm with intensity similar to those of
16 and 17 suggested that they had the same 800S,8000S configura-
tion. The 700R,7000S configuration defined by the 700,800-erythro-
7000,8000-threo configuration was supported by comparison of the
Compound 19 had spectroscopic data (Table 6 and Experi-
mental Section) similar to those of calquiquelignans D, having
undetermined absolute configuration.11 The relative configuration
00 00
for the glycerol unit in 19 could not be deduced from the J7 ,8
1
value since H-700 appeared as a broad singlet in the H NMR
spectrum in DMSO-d6.12b However, in the acetonide derivative
(19a) (Supporting Information, Figure S219 and Table S2), the
J7 ,8 value (9.4 Hz) proved the 700,800-erythro configuration for
00 00
19.16,31 The CD spectrum of 19 displayed a typical coupled
Cotton effect arising from exciton coupling between the transition
moments of the flavone and benzene chromophores, negative at
362 nm (Δε ꢀ0.13) and positive at 322 nm (Δε þ0.09)
(Supporting Information, Figure S217). On the basis of the CD
exciton chirality method,32 the negative chirality CD suggested the
700R,800S configuration for 19. The 700R configuration defined by
the 700,800-erythro was supported by a negative Cotton effect at
356 nm (the E band) in the Rh2(OCOCF3)4-induced CD
spectrum (Supporting Information, Figure S218). Hence, 19
was (ꢀ)-(700R,800S)-400,5,7-trihydroxy-30,50-dimethoxy-40,800-oxy-
flavonolignan-700,900-diol.
The spectroscopic data of 20 (Table 6 and Experimental Section)
resembled those of calquiquelignans E {[R]20 þ27.0 (c 0.48,
D
1194
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Journal of Natural Products
ARTICLE
Table 6. NMR Data (δ) for Compounds 19ꢀ22a
19
20
21
22
no.
δH
δC
δH
δC
δH
δC
δH
δC
2
163.0
104.8
181.8
161.4
98.9
163.0
104.8
181.9
161.4
99.0
162.9
104.7
181.8
161.4
99.1
162.7
104.7
181.5
161.3
99.3
3
7.05 s
7.04 s
7.02 s
7.01 s
4
5
6
6.20 d (1.8)
6.56 d (1.8)
6.20 brs
6.56 brs
6.18 brs
6.53 brs
6.17 brs
6.52 brs
7
164.4
94.3
164.4
94.3
164.3
94.3
164.3
94.5
8
9
157.4
103.8
125.2
104.2
153.0
139.4
153.0
104.2
132.5
127.9
114.4
156.2
114.4
127.9
72.0
157.4
103.8
125.3
104.3
152.9
139.9
152.9
104.3
132.3
127.8
114.4
156.2
114.4
127.8
71.5
157.4
103.6
125.2
104.2
152.9
139.4
152.9
104.2
133.2
110.9
147.0
145.4
114.7
119.4
72.1
157.5
103.7
125.4
104.2
152.9
139.8
152.9
104.2
133.0
111.0
146.9
145.4
114.6
119.1
71.6
10
10
20
30
40
50
60
100
200
300
400
500
600
700
800
900a
900b
7.30 brs
7.30 brs
7.30 brs
7.30 brs
7.30 brs
7.30 brs
7.30 brs
6.92 brs
7.30 brs
7.15 d (8.4)
6.68 d (8.4)
7.18 d (8.4)
6.67 d (8.4)
6.96 d (1.5)
6.68 d (8.4)
7.15 d (8.4)
4.77 brs
4.30 m
6.67 d (8.4)
7.18 d (8.4)
4.84 brs
4.21 m
6.68 d (8.1)
6.74 d (8.1)
4.78 brs
4.34 m
6.68 d (8.0)
6.79 d (8.0, 1.5)
4.83 brs
4.24 m
86.4
87.0
86.5
87.0
3.71 m
60.1
3.63 m
60.4
3.71 m
60.1
3.63 m
60.4
3.47 m
3.22 m
3.47 m
3.24 m
OMe-30/50
OMe-300
3.86 s
56.3
3.85 s
56.4
3.87 s
56.4
55.5
14.4
3.85 s
56.4
55.5
15.4
3.73 s
3.72 s
00ꢀC700
ΔδC8
14.4
15.5
a 1H NMR data were measured in DMSO-d6 at 300 MHz for 19 and 21, at 600 MHz for 20, and at 500 MHz for 22, respectively. Proton coupling
constants (J) in Hz are given in parentheses. 13C NMR data were measured in DMSO-d6 at 125 MHz for 19 and 22 and at 150 MHz for 20 and 21,
respectively. The assignments were based on 1Hꢀ H COSY, HSQC, and HMBC experiments.
1
MeOH)};11 however, the optical rotation of 20 {[R]20 ꢀ20.0
showed Cotton effects similar to those of 19 (Supporting
Information, Figure S234). The similarity of the CD and Rh2-
(OCOCF3)4-induced CD data between 21 and 19 (Supporting
Information, Figure S235) indicated that these analogues had the
same 700R,800S configuration. Therefore, compound 21 was
determined to be (ꢀ)-(700R,800S)-400,5,7-trihydroxy-30,300,50-tri-
methoxy-40,800-oxyflavonolignan-700,900-diol.
D
(c 0.02, MeOH)} was opposite. The 700,800-threo configuration
1
for 20 was verified by the H NMR spectrum of the acetonide
00 00
derivative (20a) showing J7 ,8 ≈ 0.0 Hz (Supporting Informa-
tion, Figure S229 and Table S2).16,31 The 700S,800S configura-
tion of 20 was also indicated by a typical coupled Cotton effect
[negative at 353 nm (Δε ꢀ0.07) and positive at 318 nm
(Δε þ0.08)] similar to that of 19, as well as by the Rh2-
(OCOCF3)4-induced positive Cotton effect at 362 nm (the E
band) opposite that of 19 (Supporting Information, Figures
S227 and S228).
The spectroscopic data of 22 (Table 6 and Experimental
Section) resembled those of salcolin A,12a,cꢀe which was reas-
signed as tricin 40-O-(threo-β-guaiacylglyceryl) ether,12b indicating
that it was the 700,800-threo isomer of 21. The 700,800-threo config-
1
00 00
Compound 21 exhibited spectroscopic data (Table 6 and
Experimental Section) similar to those of salcolin B.12 However,
the absolute configuration of salcolin B was not determined, and
it was assigned to be tricin 40-O-(erythro-β-guaiacylglyceryl)
ether,12cꢀe having a positive optical rotation opposite that of
21 {[R]D ꢀ18.3 (c 0.03, MeOH)}. The 700,800-erythro configura-
uration for 22 was proved by the J7 ,8 value (≈0.0 Hz) in the H
NMR spectrum of the acetonide derivative (22a). The 700S,800S
configuration of 22 was suggested by Cotton effects [negative at
348 nm (Δε ꢀ0.06) and positive at 318 nm (Δε þ0.07)] in the
CD spectrum and a positive Cotton effect at 366 nm (the E band)
in the Rh2(OCOCF3)4-induced CD spectrum (Supporting In-
formation, Figures S241 and S242).
00 00
tion for 21 was substantiated by the J7 ,8 value (9.0 Hz)
displayed in the 1H NMR spectrum of the acetonide derivative
(21a).16,31 Although it was reported that the CD spectrum of
salcolin A did not exhibit any Cotton effect presumably due to
conformational mobility,12d the CD spectrum of 21 in MeCN
The known compounds were identified by comparison of
spectroscopic data with those reported in the literature as (ꢀ)-
syringaresinol,26 (ꢀ)-medioresinol,33 (ꢀ)-(7R,8S)-guaiacylgly-
cerol, (þ)-(7S,8S)-guaiacylglycerol,16 tricin,34 7-methoxytricin,35
1195
dx.doi.org/10.1021/np200117y |J. Nat. Prod. 2011, 74, 1188–1200

Journal of Natural Products
ARTICLE
(ꢀ)-50-methoxyisolariciresinol,36 (þ)-lyoniresinol,13 (þ)-brugu-
nin A,37 (þ)-(7S,8S)-guaiacylglycerol-β-vanillic acid ether,38
(þ)-(70E,7S,8R)-4,7,9,90-tetrahydroxy-3,30,50-trimethoxy-8,40-
around 235 ( 5 nm could be validated for the configuration
assignment at C-8 (positive for 8S and negative for 8R) of the aryl
glycerol units in the aryl glycerols, neolignans15ꢀ17 including
sesquineolignans (10ꢀ15), and dineolignans (16ꢀ18), although
substitution of OH and/or OMe group(s) on the aryl ring(s) and
acetonationatC-7 and C-9 of the glycerol unitsvaried wavelengths
and intensities of the Cotton effect bands in the CD spectra. For
the sesquineolignans and dineolignans, the Cotton effects should
be contributed by both the aryl glycerol and 7,90:70,9-diepoxy-
lignane chromaphores in the molecules. However, it was domi-
nated by the aryl glycerol moiety. This was supported by
comparison of the CD spectra of 10ꢀ18 and acetonide derivatives
(10aꢀ15a) with those of aryl glycerols [(ꢀ)-(7R,8S)-guaiacylgly-
cerol and (þ)-(7S,8S)-guaiacylglycerol)] and 7,90:70,9-diepoxy
lignanes [9, (ꢀ)-syringaresinol, and (ꢀ)-medioresinol)] (Sup-
porting Information, Figures S244ꢀS247) as well as the related
derivatives in the literature.20 Differing from those of 2, 4,
and 10ꢀ18, the CD spectra of 19ꢀ22 exhibited typical coupled
Cotton effects (negative at 355 ( 10 nm and positive at
320 ( 5 nm, Supporting Information, Figure S248). Therefore,
the exciton chirality method32 should be applicable to determine
the configurations at C-8 of the glycerol units in 19ꢀ22. A
convenient bulkiness rule for the Rh2(OCOCF3)4-induced CD
data (the E band) was demonstrated to be useful to determine the
absolute configuration of chiral secondary and tertiary alcohols18
including the secondary benzylic alcohols.18b Application of the
method to 2ꢀ4 and 10ꢀ22 indicated that the absolute config-
urations at C-7 of the glycerol units (355 ( 10 nm, positive for 7S
and negative for 7R, predicted by the bulkiness rule) (Supporting
Information, Figures S249ꢀS250) were consistent with those
elucidated by a combination of the NMR data (determining 7,8-
threo or erythro relative configurations) and the CD data
(predicting C-8 configurations). This was supported further by
measurement of the Rh2(OCOCF3)4-induced CD spectra of(ꢀ)-
syringaresinol and tricin (Supporting Information, Figures
S249ꢀS250), which did not show any Cotton effect.
oxyneolign-70-ene,15
(ꢀ)-(70E,7R,8S)-3,4,50-trimethoxy-40,
7-epoxy-8,30-neolign-70-ene-9,90-diol,21b (þ)-(7S,8R,80R)-5,50-
dimethoxylariciresinol,39 and (þ)-50-methoxylariciresinol.40
The isolation of 7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineo-
lignan-700,900-diol derivatives from the hydrolysate of hardwood
lignin of Fraxinus mandshurica,7a 7,90:70,9-diepoxy-4,800:40,8000-
bisoxy-8,80-dineolignan-700,7000,900,9000-tetraol from the MeOH
extract of dried leaves of Hedyotis lawsoniae,9a and 40,800-oxyfla-
vonolignan-700,900-diol from the extract of Aegilops ovata41 was
reported more than 25 years ago. However, the configuration
of both the 7,90:70,9-diepoxylignane and arylglycerol moieties
in the molecules had not been substantiated due to some
contrary and controversial data reported in the literature. By
comparing the NMR and CD data of 2ꢀ4 and 10ꢀ22, in
combination with a literature survey, several points concerning
the configuration of the aryl glycerol units in these compounds
could be summarized. Our previous investigation indicated
that coupling constants (J7,8) distinct for the deshielded benzylic
proton (H-7) resonance in the 1H NMR spectra of 8,40-oxyneo-
lignanes varied in different solvents due to possible dynamic
conformational changes.16 Therefore, direct application of
the J7,8 values was ambiguous to differentiate erythro and threo
8,40-oxyneolignans with the exception of aglycone acetonides
(J7,8 > 7.0 Hz for erythro and J7,8 < 2.0 Hz for threo) and glycoside
acetates (J7,8 e 5.3 Hz for erythro and J7,8 g 6.3 Hz for threo) in
CDCl3, as well as aglycones in CDCl3 (J7,8 e 5.0 Hz for erythro
and J7,8 g 7.0 Hz for threo).16 In addition, the ΔδC8ꢀC7 values
eliminating the effect of systematic errors [ΔδC8ꢀC7(threo) >
ΔδC8ꢀC7(erythro)] were also applicable to differentiate threo and
erythro aryl glycerols without substituent(s) at C-7 or/and C-8 of
the glycerol moiety42 as well as the erythro and threo 8,40-
oxyneolignane isomers16 when the data were obtained in the
same solvent. Inspection of the NMR data obtained in Me2CO-
d6 and/or CDCl3 (Tables 1ꢀ5) indicated that the coupling
The inhibitory effects of the isolates against nitric oxide (NO)
production in mouse peritoneal macrophages were examined.
Compounds 20 and 22 inhibited NO elevation by 84.2 ( 5.9%
and 71.7 ( 1.0%, respectively, at a concentration of 10 μM, while
the positive control dexamethasone gave an inhibitory rate of 61.6
( 1.3% at the same concentration. The other compounds showed
inhibitory rates less than 30%. The protective activities of the
compounds against neurotoxicity induced by serum deprivation in
PC12 cells were investigated by the MTT method. The results
showed that serum deprivation induced significant inhibition of
MTT reduction, at a concentration of 10 μM. Compounds 19, 20,
and 22 increased cell viability from 80.7 ( 2.8% to 91.6 ( 6.4%,
107.2 ( 8.0%, and 97.6 ( 8.5%, respectively, indicating that they
may be effective in neurodegenerative disorders. The isolates were
00 00
constants for the erythro aryl glycerol moieties (J7 ,8 for 4, 10,
000,8000
12, 14, 16, and 18; J7
for 16; <4.0 Hz) were smaller than
00 00
those for threo isomers (J7,8 for 2, 3, and 3a; J7 ,8 for 11, 13, 15,
000,8000
and 17; and J7
for 17 and 18; >6.0 Hz). Meanwhile, chemical
00
00
shift differences for the erythro aryl glycerol moieties (ΔδC8 ꢀC7
for 4, 10, 12, 14, 16, and 18; ΔδC8 for 16; <14.6 ppm)
000ꢀC7000
00
00
were smaller than those for the threo moieties (ΔδC8 ꢀC7 for
000ꢀC7000
11, 13, 15, and 17; ΔδC8
for 17 and 18; >14.8 ppm).
00 00
Although the J7 ,8 values for 19ꢀ22 in DMSO-d6 (Table 6) and
pyridine-d5 were indistinguishable12b and it was reported that the
00 00
data (J7 ,8 ) in CD3OD and CD3CN for the erythro forms (19 and
21) were smaller than those for the threo forms (20 and 22),12 the
00
00
ΔδC8 ꢀC7 values in the different solvents for the erythro analo-
gues were consistently smaller than those for the threo derivatives.
This was fully consistent with our previous reports,16,42 supporting
the validity of direct application of ΔδC8ꢀC7 values to distinguish
threo and erythro arylglycerol units in the different neolignans. This
was confirmed by the coupling constants in the 1H NMR spectra
also assessed for their activities against HIV-1 replication,43 Fe2þ
-
cystine-induced rat liver microsomal lipid peroxidation,44 and DL-
galactosamine-induced WB-F344 cell damage45 as well as cyto-
toxicity against several human cancer cell lines,46 but were inactive
at a concentration of 10 μM.
00 00
of the corresponding acetonide derivatives (J7 ,8 for 4a, 10a, 12a,
000,8000
14a, 16a, 18a, 19a, and 21a and J7
for 16a > 9.0 Hz, whereas
’ EXPERIMENTAL SECTION
00 00
000,8000
J7,8 for 2a, J7 ,8 for 11a, 13a, 15a, 17a, 20a, and 22a, and J7
for
17a and 18a < 2.0 Hz).
General Experimental Procedures. Optical rotations were
measured on a Rudolph Research Autopol III automatic polarimeter.
UV spectra were measured on a Cary 300 spectrometer. CD spectra
were recorded on a JASCO J-815 CD spectrometer. IR spectra were
Detailed analysis of the CD data of compounds 2, 4, 10ꢀ18,
and 10aꢀ15a and our previous investigation,16 together with
literature surveys,15,17,20 indicated that the La Cotton effects at
1
1196
dx.doi.org/10.1021/np200117y |J. Nat. Prod. 2011, 74, 1188–1200

Journal of Natural Products
ARTICLE
recorded on a Nicolet 5700 FT-IR microscope instrument (FT-IR
microscope transmission). NMR spectra were obtained at 300, 500, or
600 MHz for 1H and 125 or 150 MHz for 13C, respectively, on Varian
Mecury-300 MHz or INOVA 500 MHz or SYS 600 MHz spectrometers
with solvent peaks being used as references. ESIMS data were measured
with a Q-Trap LC/MS/MS (Turbo Ionspray Source) spectrometer.
HRESIMS data were measured using an Agilent Technologies 6520
Accurate Mass Q-ToF LC/MS spectrometer. Column chromatography
was performed using silica gel (200ꢀ300 mesh, Qingdao Marine
Chemical Inc., China) and Sephadex LH-20 (Pharmacia Biotech AB,
Uppsala Sweden). HPLC separation was performed on an instrument
consisting of a Waters 600 controller, a Waters 600 pump, and a Waters
2487 dual λ absorbance detector with an Alltima (250 ꢁ 10 mm)
preparative column packed with C18 (5 μm). TLC was carried out on
precoated silica gel GF254 plates. Spots were visualized under UV light
(254 or 356 nm) or by spraying with 7% H2SO4 in 95% EtOH followed
by heating.
125 MHz) data, see Table 2; (þ)-ESIMS m/z 419 [M þ H]þ, 441 [M þ
Na]þ, 457 [M þ K]þ; (þ)-HRESIMS m/z 441.1532 [M þ Na]þ (calcd
for C22H26O8Na, 441.1520).
(þ)-(7S,8S)-10,4-Dihydroxy-3,30,50-trimethoxy-70,80,90-trinor-8,40-
oxyneolignan-7,9-diol (2): white, amorphous powder; [R]20D þ3.5 (c
0.10, MeOH); UV (MeOH) λmax (log ε) 204 (4.30), 234 (3.64), 280
(3.10) nm; CD (MeOH) 207 (Δε þ1.32), 224.5 (Δε þ0.20), 237 (Δε
þ0.41) nm; Rh2(OCOCF3)4 -induced CD (CH2Cl2) 319 (Δε ꢀ0.01),
329 (Δε ꢀ0.04), 351 (Δε þ0.08) nm; IR νmax 3405, 2939, 2849, 1603,
1512, 1481, 1434, 1368, 1274, 1217, 1032, 996, 821, 632 cmꢀ1; 1H NMR
(Me2CO-d6, 500 MHz) data, see Table 1; 13C NMR (Me2CO-d6, 125
MHz) data, see Table 2; (þ)-ESIMS m/z 389 [M þ Na]þ, 405 [M þ
K]þ, 755 [2 M þ Na]þ; (þ)-HRESIMS m/z 389.1208 [M þ Na]þ
(calcd for C18H22O8Na, 389.1207).
(þ)-(7S,8S)-4-Hydroxy-3,30,50-trimethoxy-80,90-dinor-8,40-oxyneo-
lignan-7,9-diol-70-oic acid (3): white, amorphous powder; [R]20D þ13.4
(c 0.13, MeOH); UV (MeOH) λmax (log ε) 204 (4.15), 256 (3.37), 284
(3.08) nm; CD (MeOH) 227 (Δε ꢀ0.22), 258 (Δε þ0.50) nm; Rh2-
(OCOCF3)4-inducedCD (CH2Cl2) 319.5 (Δε ꢀ0.15), 359(Δε þ0.06),
429 (Δε ꢀ0.01) nm; IR νmax 3423, 2941, 2845, 1564, 1519, 1459, 1404,
1224, 1124, 1031, 789, 767 cmꢀ1; 1H NMR (MeOH-d4, 500 MHz) data,
see Table 1; 13C NMR (MeOH-d4, 125 MHz) data, see Table 2; ESIMS
m/z 417 [M þ Na]þ, 393 [M ꢀ H]ꢀ; (þ)-HRESIMS m/z 417.1164
[M þ Na]þ (calcd for C19H22O9Na, 417.1156).
Plant Material. The skin-removed stems of S. affinis were collected
at Pingle Town, Sichuang Province, China, in August 2008. Plant
identification was verified by Dr. Yan Ren (Chengdu University of
TCM, Sichuan 610075, China). A voucher specimen (no. ID-S-2326)
was deposited at the Herbarium of the Department of Medicinal Plants,
Institute of Materia Medica, Beijing 100050, China.
Extraction and Isolation. Air-dried slices of the skin-removed
stem of S. affinis (6 kg) were powdered and extracted with 95% EtOH
(3 ꢁ 40 L) at rt for 3 ꢁ 72 h. The EtOH extract was evaporated under
reduced pressure to yield a dark brown residue (330 g). The residue was
suspended in H2O (2500 mL) and then partitioned with EtOAc (6 ꢁ
2500 mL). After removing the solvent, the EtOAc fraction (120 g) was
applied to a silica gel column. Successive elution with a gradient of
increasing acetone (0ꢀ100%) in petroleum ether afforded 10 fractions
(F1ꢀF10) based on TLC analysis. F5 (8.5 g) was subjected to RP flash
CC (40ꢀ95% MeOH in H2O) to give subfractions F5-1ꢀF5-5. Separa-
tion of F5-2 (1.1 g) with Sephadex LH-20 (petroleum etherꢀCHCl3ꢀ
MeOH, 5:5:1) and RP semipreparative HPLC (50% MeOH in H2O),
successively, yielded 9 (4 mg). F5-3 (4.57 g) was fractioned via silica gel
(30ꢀ100% EtOAc in petroleum ether) and Sephadex LH-20
(petroleum etherꢀCHCl3ꢀMeOH, 5:5:1) followed by RP semipre-
parative HPLC (55% MeOH in H2O) purification to yield 5 (8 mg) and
6 (11 mg). Eluting with a step gradient of 30ꢀ95% MeOH in H2O, F6
(21.0 g) was separated by flash chromatography over MCI gel, to give
subfractions F6-1ꢀF6-5. F6-2 (6.0 g) was purified via silica gel (5ꢀ40%
acetone in CHCl3) followed by RP semipreparative HPLC (40% MeOH
in H2O) to yield 1 (6 mg), 2 (6 mg), 3 (7 mg), 7 (87 mg), and 8 (5 mg).
F6-3 (2.0 g) was subjected to Sephadex LH-20, successively using
petroleum etherꢀCHCl3ꢀMeOH (2:2:1) and CHCl3ꢀMeOH (1:1)
as mobile phases, to afford 19 (260 mg), 20 (145 mg), 21 (21 mg), and
22 (18 mg). F6-4 (4.6 g) was fractioned by RP flash chromatography
(30ꢀ70% MeOH in H2O) to give F6-4-1ꢀF6-4-6. F6-4-2 (0.5 g) and F6-4-3
(0.7 g) were subjected separately to RP semipreparative HPLC (55%
MeOH in H2O) to yield 14 (150 mg) and 15 (147 mg) from F6-4-2 and
12 (217 mg) and 13 (150 mg) from F6-4-3. F6-4-4 (1.2 g) was separated
successively by chromatography over Sephadex LH-20 (CHCl3ꢀ
MeOH, 1:1) and RP semipreparative HPLC (60% MeOH in H2O) to
afford 10 (146.0 mg), 11 (85 mg), and 17 (3 mg). Separation of F6-4-4
(0.6 g) by RP semipreparative HPLC (45% CH3CN in H2O) yielded 4
(5 mg), 16 (150 mg), and 18 (180 mg).
Methylation of 3. A solution of compound 3 (2.0 mg) in dry
acetone (3 mL) was treated with NaHCO3 (1.5 mg) and CH3I (2.5 mg)
at 50 °C for 8 h. The reaction mixture was evaporated under reduced
pressure to give a residue. The residue was partitioned between H2O
(10 mL) and EtOAc (10 mL). The EtOAc extract was evaporated, and
then purified by preparative TLC using CHCl3ꢀMeOH (15:1) to afford
3a (1.3 mg): white, amorphous powder; [R]20D þ2.7 (c 0.10, MeOH);
UV (MeOH) λmax (log ε) 202 (4.31), 217 (4.01), 270 (3.55) nm; CD
(MeOH) 243 (Δε þ0.26), 262 (Δε þ0.41) nm; Rh2(OCOCF3)4-
induced CD (CH2Cl2) 320 (Δε þ0.06), 356 (Δε þ0.02) nm; 1H NMR
(MeOH-d4, 600 MHz) data, see Table 1; 13C NMR (MeOH-d4, 150
MHz) data, see Table 2; (þ)-ESIMS m/z 431 [M þ Na]þ.
(ꢀ)-(7R,8S,700S,800R)-3,300,5,50-Tetramethoxy-400-hydroxy-40,7-epoxy-
80,90-dinor-4,800-oxy-8,30-sesquineolignan-700,9,900-triol-70-al (4): white,
amorphous powder; [R]20D ꢀ3.0 (c 0.07, CH2Cl2); UV (MeOH) λmax
(log ε) 205 (4.22), 235 (3.77), 286 (3.44), 310 (3.35) nm; CD (MeOH)
212 (Δε þ1.41), 236 (Δε ꢀ0.47), 280 (Δε þ0.03), 295 (Δε ꢀ0.15), 320
(Δε þ0.06) nm; Rh2(OCOCF3)4-induced CD (CH2Cl2) 313.5 (Δε
þ0.01), 327.5 (Δε ꢀ0.02), 347.5 (Δε þ0.06), 397 (Δε þ0.01) nm; IR
νmax 3429, 2939, 2844, 1680, 1592, 1514, 1462, 1426, 1325, 1225, 1127,
1031, 949, 830 cmꢀ1; 1H NMR (Me2CO-d6, 500 MHz) data, see Table 3;
13C NMR(Me2CO-d6, 125MHz) data, see Table 4; (þ)-ESIMS m/z 579
[M þ Na]þ; (ꢀ)-ESIMS m/z 555 [M ꢀ H]ꢀ; (þ)-HRESIMS m/z
579.1845 [M þ Na]þ (calcd for C29H32O11Na, 579.1837).
(ꢀ)-(7R,8S,70E)-3,4,5,50-Tetramethoxy-40,7-epoxy-8,30-neolign-70-
ene-9,90-diol (5): white, amorphous powder; [R]20 ꢀ7.8 (c 0.10,
D
MeOH); UV (MeOH) λmax (log ε) 206 (4.26), 275 (3.71) nm; CD
(MeOH) 203 (Δε þ7.58), 220 (Δε ꢀ0.37), 234 (Δε þ3.76), 272 (Δε
ꢀ2.89) nm; IR νmax 3397, 2937, 1595, 1499, 1463, 1420, 1330, 1237,
1126, 965, 834, 616 cmꢀ1; 1H NMR (Me2CO-d6, 500 MHz) data, see
Table 1; 13C NMR (Me2CO-d6, 125 MHz) data, see Table 2; (þ)-
ESIMS m/z 425 [M þ Na]þ, 441 [M þ K]þ; (þ)-HRESIMS m/z
403.1741 [M þ H]þ (calcd for C22H27O7 403.1751).
(þ)-(70S,8S,80S)-30,4-Dihydroxy-20,3,40,5-tetramethoxy-60,9-epoxy-
2,70-cyclolignan-90-ol (1): white, amorphous powder; [R]20D þ43.3 (c
0.12, MeOH); UV (MeOH) λmax (log ε) 207 (4.28), 235 (3.68), 282
(3.24) nm; CD (MeOH) 226 (Δε ꢀ2.23), 247 (Δε þ0.78) nm, 284
(Δε ꢀ1.03) nm; IR νmax 3432, 3246, 2963, 2935, 2897, 1612, 1493,
1451, 1437, 1305, 1235, 1195, 1125, 1091, 1033, 919, 872, 809 cmꢀ1; 1H
NMR (MeOH-d4, 500 MHz) data, see Table 1; 13C NMR (MeOH-d4,
(þ)-(7S,8R,70E)-4-Hydroxy-3,50-dimethoxy-40,7-epoxy-8,30-neolign-
70-ene-9,90-diol 90-ethyl ether (6): white, amorphous powder; [R]20
D
þ11.8 (c 0.10, MeOH); UV (MeOH) λmax (log ε) 204 (4.16), 278
(3.67) nm; CD (MeOH) 211 (Δε þ2.82), 238 (Δε ꢀ0.88), 261 (Δε
þ1.74), 282.5 (Δε þ3.30) nm; IR νmax 3365, 2970, 2928, 2852, 1603,
1517, 1497, 1464, 1331, 1274, 1212, 1144, 1033, 967, 856, 816 cmꢀ1; 1H
NMR (Me2CO-d6, 500 MHz) data, see Table 1; 13C NMR (Me2CO-d6,
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Journal of Natural Products
ARTICLE
125 MHz) data, see Table 2; (þ)-ESIMS m/z 409 [M þ Na]þ, 425 [M
þ K]þ; (þ)-HRESIMS m/z 409.1622 [M þ Na]þ (calcd for
C22H26O6Na, 409.1622).
(MeCN) 214.5 (Δε ꢀ1.44), 223 (Δε þ0.54) nm, 230 (Δε ꢀ1.12), 240
(Δε þ0.77), 251 (Δε ꢀ0.24), 269 (Δε þ0.78), 279 (Δε ꢀ0.24), 288
(Δε ꢀ0.21) nm; Rh2(OCOCF3)4-induced CD (CH2Cl2) 334 (Δε
þ0.03), 351 (Δε ꢀ0.04), 364 (Δε ꢀ0.02), 374 (Δε ꢀ0.03) nm; IR νmax
3303, 2962, 1593, 1518, 1463, 1262, 1224, 1113, 1028, 803 cmꢀ1; 1H
NMR (Me2CO-d6, 500 MHz and CDCl3, 500 MHz) data, see Table 3;
13C NMR (Me2CO-d6, 125 MHz and CDCl3, 125 MHz) data, see
Table 4; (þ)-ESIMS m/z 637 [M þ Na]þ; (ꢀ)-ESIMS m/z 613 [M ꢀ
(ꢀ)-(70S,8S,80R)-4,40-Dihydroxy-3,30,5,50-tetramethoxy-70,9-epoxy-
lignan-90-ol-7-one (7): white, amorphous powder; [R]20D ꢀ1.5 (c 0.20,
MeCN); UV (MeOH) λmax (log ε) 208 (4.18), 233 (3.73), 303
(3.47) nm; CD (MeOH) 209 (Δε ꢀ0.36), 225 (Δε ꢀ0.55), 255 (Δε
þ0.27), 273 (Δε þ0.05), 286 (Δε þ0.14), 324 (Δε ꢀ0.16) nm; IR νmax
3473, 3285, 2940, 1661, 1611, 1518, 1463, 1425, 1325, 1218, 1116, 1033,
H]ꢀ; (þ)-HRESIMS m/z 637.2263 [M
þ
Na]þ (calcd for
842, 715 cmꢀ1; 1H NMR (MeOH-d4, 500 MHz) data, see Table 1; 13
C
C32H38O12Na, 637.2255).
(ꢀ)-(7R,70R,700S,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5,50-pentameth-
oxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol (13):
white, amorphous powder; [R]20D ꢀ6.0 (c 0.10, MeCN); UV (MeOH)
λmax (log ε) 206 (4.21), 238 (3.50), 277 (2.81) nm; CD (MeCN) 214.5
(Δε ꢀ0.95), 223.5 (Δε þ0.86), 231 (Δε ꢀ0.17), 238.5 (Δε þ0.66),
246 (Δε ꢀ0.16), 255 (Δε þ0.54), 260 (Δε þ0.40), 267 (Δε þ0.77),
278 (Δε ꢀ0.19), 290.5 (Δε ꢀ0.30) nm; Rh2(OCOCF3)4-induced CD
(CH2Cl2) 336 (Δε ꢀ0.11), 353 (Δε þ0.09), 394 (Δε þ0.01) nm; IR
νmax 3450, 2940, 2842, 1593, 1518, 1463, 1425, 1368, 1328, 1273, 1221,
1121, 1059, 1033, 826, 702 cmꢀ1; 1H NMR (Me2CO-d6, 500 MHz and
CDCl3, 500 MHz) data, see Table 3; 13C NMR (Me2CO-d6, 125 MHz
and CDCl3, 125 MHz) data, see Table 4; (þ)-ESIMS m/z 637 [M þ
Na]þ; (ꢀ)-ESIMS m/z 613 [M ꢀ H]ꢀ; (þ)-HRESIMS m/z 637.2257
[M þ Na]þ (calcd for C32H38O12Na, 637.2255).
NMR (MeOH-d4, 125 MHz) data, see Table 2; (þ)-ESIMS m/z 435 [M
þ H]þ, 457 [M þ Na]þ, 473 [M þ K]þ; (ꢀ)-ESIMS m/z 433 [M ꢀ
H]ꢀ; (þ)-HRESIMS m/z 457.1472 [M
þ
Na]þ (calcd for
C22H26O9Na, 457.1469).
(þ)-(7R,70R,8S,80S)-40-Hydroxy-3,30,4,5,50-pentamethoxy-7,70-epox-
ylignan-9,90-diol (8): white, amorphous powder; [R]20D þ25.5 (c 0.04,
MeOH); UV (MeOH) λmax (log ε) 207 (4.48), 241 (3.72), 277
(3.03) nm; CD (MeOH) 207 (Δε ꢀ16.55), 221.5 (Δε þ0.87), 226
(Δε þ0.28), 243 (Δε þ10.94), 277 (Δε ꢀ0.56) nm; IR νmax 3381,
1
2936, 1595, 1514, 1462, 1424, 1329, 1236, 1124, 834, 718 cmꢀ1; H
NMR (Me2CO-d6, 500 MHz) data, see Table 1; 13C NMR (Me2CO-d6,
125 MHz) data, see Table 2; (þ)-ESIMS m/z 473 [M þ Na]þ, 489
[M þ K]þ; (þ)-HRESIMS m/z 473.1784 [M þ Na]þ (calcd for
C23H30O9Na, 473.1782).
(ꢀ)-(7R,70R,700R,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5,50,500-hexa-
methoxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol (14):
white, amorphous powder; [R]20D ꢀ3.0 (c 0.05, MeCN); UV (MeOH)
λmax (log ε) 206 (4.29), 238 (3.59), 277 (2.93) nm; CD (MeCN) 213
(Δε ꢀ2.61), 223 (Δε þ0.08), 229.5 (Δε ꢀ0.58), 239 (Δε þ1.11), 249
(Δε ꢀ0.33), 269 (Δε þ0.53), 279 (Δε ꢀ0.17), 290.5 (Δε ꢀ0.15) nm;
Rh2(OCOCF3)4-induced CD (CH2Cl2) 335.5 (Δε ꢀ0.05), 344
(Δε ꢀ0.01), 353.5 (Δε ꢀ0.03), 364 (Δε ꢀ0.01) nm; IR νmax 3346,
2939, 2841, 1614, 1519, 1462, 1425, 1326, 1218, 1118, 829, 702 cmꢀ1; 1H
NMR (Me2CO-d6, 500 MHz and CDCl3, 500 MHz) data, see Table 3;
13C NMR (Me2CO-d6, 125 MHz and CDCl3, 125 MHz) data, see
Table 4; (þ)-ESIMS m/z 667 [M þ Na]þ; (ꢀ)-ESIMS m/z 643 [M ꢀ
H]ꢀ; (þ)-HRESIMSm/z667.2365 [M þ Na]þ (calcd for C33H40O13Na,
637.2361).
(ꢀ)-(7R,70R,8S,80S)-40-Hydroxy-3,30,4,5,50-pentamethoxy-7,90:70,9-
diepoxylignane (9): white, amorphous powder; [R]20 ꢀ45.8 (c 0.03,
D
MeOH); UV (MeOH) λmax (log ε) 207 (4.27), 236 (3.55), 272
(2.86) nm; CD (MeCN) 214 (Δε ꢀ3.79), 230.5 (Δε ꢀ0.62), 239
(Δε ꢀ0.86), 254 (Δε þ0.09), 274 (Δε ꢀ0.72) nm; IR νmax 3370, 2935,
2850, 1593, 1510, 1460, 1421, 1329, 1234, 1122, 1005, 830, 701 cmꢀ1; 1H
NMR (Me2CO-d6, 600 MHz) data, see Table 1; 13C NMR (Me2CO-d6,
125 MHz) data, see Table 2; (þ)-EIMS m/z 432 [M]þ; (þ)-HRESIMS
m/z 455.1677 [M þ Na]þ (calcd for C23H28O8Na, 455.1676).
(ꢀ)-(7R,70R,700R,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5-tetrameth-
oxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol (10):
white, amorphous powder; [R]20D ꢀ4.0 (c 0.10, MeCN); UV (MeOH)
λmax (log ε) 204 (4.35), 233 (3.71), 280 (3.12) nm; CD (MeCN) 207
(Δε ꢀ0.19), 215.5 (Δε ꢀ0.98), 225 (Δε þ0.25) nm, 230 (Δε ꢀ0.10),
238.5 (Δε þ1.08), 247.5 (Δε ꢀ0.10), 267 (Δε þ0.80), 281 (Δε
ꢀ0.33), 293 (Δε ꢀ0.42) nm; Rh2(OCOCF3)4-induced CD (CH2Cl2)
327 (Δε ꢀ0.07), 340 (Δε ꢀ0.01), 353 (Δε ꢀ0.04) nm; IR νmax 3421,
2939, 1593, 1517, 1463, 1426, 1274, 1232, 1125, 1033, 823 cmꢀ1; 1H
NMR (Me2CO-d6, 500 MHz and CDCl3, 500 MHz) data, see Table 3;
13C NMR (Me2CO-d6, 125 MHz and CDCl3, 125 MHz) data, see
Table 4; (þ)-ESIMS m/z 607 [M þ Na]þ; (ꢀ)-ESIMS m/z 583 [M ꢀ
(ꢀ)-(7R,70R,700S,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5,50,500-hexa-
methoxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol (15):
white, amorphous powder; [R]20D ꢀ5.0 (c 0.10, MeCN); UV (MeOH)
λmax (log ε) 207 (4.22), 240 (3.47), 274 (2.65) nm; CD (MeCN) 209.5
(Δε ꢀ2.98), 223 (Δε þ1.09), 230.5 (Δε ꢀ0.35), 237.5 (Δε þ0.97), 244
(Δε þ0.31), 253.5 (Δε þ0.70), 261.5 (Δε þ0.07), 268.5 (Δε þ0.62),
283 (Δε ꢀ0.27), 296 (Δε ꢀ0.37) nm; Rh2(OCOCF3)4-induced CD
(CH2Cl2) 335 (Δε ꢀ0.12), 354 (Δε þ0.07), 383 (Δε þ0.05) nm; IR
νmax 3441, 2939, 2842, 1613, 1519, 1462, 1326, 1218, 1119, 830,
H]ꢀ; (þ)-HRESIMS m/z 607.2155 [M
þ
Na]þ (calcd for
C31H36O11Na, 607.2150).
1
702 cmꢀ1; H NMR (Me2CO-d6, 500 MHz and CDCl3, 500 MHz)
(ꢀ)-(7R,70R,700S,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5-tetramethoxy-
data, see Table 3; 13C NMR (Me2CO-d6, 125 MHz and CDCl3, 125
MHz) data, see Table 4; (þ)-ESIMS m/z 667 [M þ Na]þ; (ꢀ)-ESIMS
m/z 643 [M ꢀ H]ꢀ; (þ)-HRESIMS m/z 667.2368 [M þ Na]þ (calcd
for C33H40O13Na, 637.2361).
7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol (11): white,
amorphous powder; [R]20 ꢀ4.8 (c 0.10, MeCN); UV (MeOH) λmax
D
(log ε) 204 (4.33), 232 (3.73), 280 (3.20) nm; CD (MeCN) 208
(Δε ꢀ1.61), 214.5 (Δε ꢀ0.30), 218.5 (Δε ꢀ0.69) nm, 226 (Δε þ0.11),
239.5 (Δε þ0.58), 249 (Δε ꢀ0.36), 266.5 (Δε þ0.85), 279 (Δε ꢀ0.16),
291 (Δε ꢀ0.55) nm; Rh2(OCOCF3)4-induced CD (CH2Cl2) 336
(Δε ꢀ0.01), 348 (Δε þ0.06) nm; IR νmax 3447, 2940, 1593, 1517,
1463, 1426, 1274, 1233, 1124, 1033, 824 cmꢀ1; 1H NMR (Me2CO-d6,
500 MHz and CDCl3, 500 MHz) data, see Table 3; 13C NMR (Me2CO-
d6, 125 MHz and CDCl3, 125 MHz) data, see Table 4; (þ)-ESIMS m/z
607 [M þ Na]þ; (ꢀ)-ESIMS m/z 583 [M ꢀ H]ꢀ; (þ)-HRESIMS m/z
607.2143 [M þ Na]þ (calcd for C31H36O11Na, 607.2150).
(þ)-(7R,70R,700R,7000R,8S,80S,800S,8000S)-400,4000-Dihydroxy-3,30,300,3000,
5,50-hexamethoxy-7,90:70,9-diepoxy-4,800:40,8000-bisoxy-8,80-dineolignan-
700,7000,900,9000-tetraol (16): white, amorphous powder; [R]20 þ1.2
D
(c 0.25, MeCN); UV (MeOH) λmax (log ε) 204 (4.44), 232 (3.81),
278 (3.20) nm; CD (MeCN) 209 (Δε ꢀ1.31), 215 (Δε ꢀ1.71), 234
(Δε þ0.94), 249 (Δε ꢀ0.93), 272 (Δε þ0.38), 287 (Δε ꢀ0.46) nm;
Rh2(OCOCF3)4-induced CD (CH2Cl2) 329 (Δε þ0.03), 351
(Δε ꢀ0.07), 378 (Δε ꢀ0.02) nm; IR νmax 3442, 2970, 2938, 1592,
1517, 1463, 1423, 1231, 1125, 1035, 825, 702 cmꢀ1; 1H NMR (Me2CO-
d6, 300 MHz) data, see Table 5; 13C NMR (Me2CO-d6, 125 MHz) data,
see Table 5; (þ)-ESIMS m/z 833 [M þ Na]þ; (ꢀ)-ESIMS m/z 809
(ꢀ)-(7R,70R,700R,8S,80S,800S)-40,400-Dihydroxy-3,30,300,5,50-penta-
methoxy-7,90:70,9-diepoxy-4,800-oxy-8,80-sesquineolignan-700,900-diol
(12): white, amorphous powder; [R]20 ꢀ3.0 (c 0.05, MeCN); UV
D
(MeOH) λmax (log ε) 205 (4.38), 235 (3.71), 277 (3.09) nm; CD
1198
dx.doi.org/10.1021/np200117y |J. Nat. Prod. 2011, 74, 1188–1200

Journal of Natural Products
ARTICLE
[M ꢀ H]ꢀ; (þ)-HRESIMS m/z 833.2984 [M þ Na]þ (calcd for
C42H50O16Na, 833.2991).
(ꢀ)-(700R,800S)-400,5,7-Trihydroxy-30,300,50-trimethoxy-40,800-oxyfla-
vonolignan-700,900-diol (21): yellow, amorphous powder; [R]20D ꢀ18.3
(c 0.03, MeOH); UV (MeOH) λmax (log ε) 203 (4.15), 271 (3.56), 337
(3.56) nm; CD (MeCN) 207 (Δε þ0.79), 232 (Δε ꢀ0.45), 271 (Δε
þ0.19), 294 (Δε 0.00), 320 (Δε þ0.12), 356 (Δε ꢀ0.12) nm; Rh2-
(OCOCF3)4-induced CD (CH2Cl2) 331 (Δε ꢀ0.07), 353.5 (Δε ꢀ0.03),
377 (Δε 0.00), 404 (Δε ꢀ0.01); IR νmax 3421, 2924, 1655, 1618, 1592,
1498, 1460, 1357, 1248, 1165, 1126, 839 cmꢀ1; 1H NMR (DMSO-d6, 300
MHz) data, see Table 6; 13C NMR (DMSO-d6, 150 MHz) data, see
Table 6; (ꢀ)-ESIMS m/z 525 [M ꢀ H]ꢀ.
(þ)-(7R,70R,700S,7000S,8S,80S,800S,8000S)-400,4000-Dihydroxy-3,30,300,3000,
5,50-hexamethoxy-7,90:70,9-diepoxy-4,800:40,8000-bisoxy-8,80-dineolignan-
700,7000,900,9000-tetraol (17): white, amorphous powder; [R]20 þ1.2 (c
D
0.10, MeCN); UV (MeOH) λmax (log ε) 205 (4.39), 234 (3.77), 278
(3.20) nm; CD (MeCN) 210.5 (Δε þ0.24), 219 (Δε ꢀ1.66), 234.5 (Δε
þ1.14), 254 (Δε ꢀ0.46), 266.5 (Δε þ0.60), 278 (Δε ꢀ0.44) nm;
Rh2(OCOCF3)4-induced CD (CH2Cl2) 350 (Δε þ0.13), 385 (Δε
þ0.02) nm; IR νmax 3354, 2924, 2851, 1593, 1516, 1463, 1423, 1273,
1231, 1124, 1033, 825 cmꢀ1; 1H NMR (Me2CO-d6, 500 MHz) data, see
Table 5; 13C NMR (Me2CO-d6, 125 MHz) data, see Table 5;(þ)-ESIMS
m/z 833 [M þ Na]þ; (ꢀ)-ESIMS m/z 809 [M ꢀ H]ꢀ; (þ)-HRESIMS
m/z 833.3001 [M þ Na]þ (calcd for C42H50O16Na, 833.2991).
(ꢀ)-(700S,800S)-400,5,7-Trihydroxy-30,300,50-trimethoxy-40,800-oxyfla-
vonolignan-700,900-diol (22): yellow, amorphous powder; [R]20D ꢀ11.2
(c 0.03, MeOH); UV (MeOH) λmax (log ε) 203 (4.18), 279 (3.62), 336
(3.51) nm; CD (MeCN) 221 (Δε þ0.24), 241 (Δε ꢀ0.37), 267 (Δε
þ0.27), 298 (Δε ꢀ0.02), 318 (Δε þ0.07), 348 (Δε ꢀ0.06) nm;
Rh2(OCOCF3)4-induced CD (CH2Cl2) 325 (Δε ꢀ0.13), 366 (Δε
þ0.05), 452 (Δε þ0.01) nm; IR νmax 3381, 2941, 1654, 1614, 1505,
(þ)-(7R,70R,700R,7000S,8S,80S,800S,8000S)-400,4000-Dihydroxy-3,30,300,3000,
5,50-hexamethoxy-7,90:70,9-diepoxy-4,800:40,8000-bisoxy-8,80-dineolignan-
700,7000,900,9000-tetraol (18): white, amorphous powder; [R]20 þ2.1 (c
D
1
1463, 1355, 1263, 1160, 1117, 835 cmꢀ1; H NMR (DMSO-d6, 500
0.10, MeCN); UV (MeOH) λmax (log ε) 204 (4.43), 233 (3.79), 278
(3.18) nm; CD (MeCN) 208 (Δε ꢀ0.24), 217 (Δε ꢀ0.85), 235 (Δε
þ0.67), 245 (Δε þ0.33), 257 (Δε ꢀ0.68), 269 (Δε þ0.30), 283
(Δε ꢀ0.15) nm; Rh2(OCOCF3)4-induced CD (CH2Cl2) 349 (Δε
þ0.04); IR νmax 3476, 2933, 2850, 1592, 1517, 1463, 1423, 1273, 1231,
1124, 1032, 824, 703 cmꢀ1; 1H NMR (Me2CO-d6, 500 MHz) data, see
Table 5; 13C NMR (Me2CO-d6, 125 MHz) data, see Table 5;(þ)-ESIMS
m/z 833 [M þ Na]þ; (ꢀ)-ESIMS m/z 809 [M ꢀ H]ꢀ; (þ)-HRESIMS
m/z 833.2997 [M þ Na]þ (calcd for C42H50O16Na, 833.2991).
MHz) data, see Table 6; 13C NMR (DMSO-d6, 125 MHz) data, see
Table 6; (ꢀ)-ESIMS m/z 525 [M ꢀ H]ꢀ.
Preparation of Acetonide Derivatives of 10aꢀ15a and
18aꢀ22a. A solution of 10 (5.0 mg) in dry acetone (5 mL) was treated
with 2,2-dimethoxypropane (8.0 mL) and (1S)-(þ)-camphorsulforic
acid (CSA) (0.5 mg), and the mixture was stirred at rt for 4 h. The
reaction mixture was quenched by addition of triethylamine and then
evaporated under reduced pressure to give a crude product that was
purified by PTLC using CHCl3ꢀMeOH (20:1) to afford acetonide 10a
(4.1 mg). Similarly, 11 (5.6 mg), 12 (4.3 mg), 13 (8.4 mg), 14 (5.0 mg),
15 (4.7 mg), 18 (5.0 mg), 19 (4.5 mg), 20 (4.0 mg), 21 (4.4 mg), and 22
(4.5 mg) yielded acetonide derivatives 11a (4.0 mg), 12a (3.2 mg), 13a
(6.9 mg), 14a (4.3 mg), 15a (3.3 mg), 18a (3.8 mg), 19a (3.2 mg), 20a
(2.4 mg), 21a (3.5 mg), and 22a (3.0 mg), respectively. 1H NMR
(Me2CO-d6, 500 MHz) data of 10aꢀ15a, see Supporting Information,
Table S1; 13C NMR (Me2CO-d6, 125 MHz) data of 10aꢀ15a, see
Supporting Information, Table S1; 1H NMR data (DMSO-d6, 500
MHz) data of 19aꢀ22a, see Supporting Information, Table S2.
Alkali Hydrolysis of 10ꢀ18. To a solution of compound 10 (8.0
mg) in dioxane (5 mL) was added 2 mol/L NaOH (0.5 mL). The
reaction mixture was stirred at rt for 5 days. After neutralization with
diluted HCl the reaction solution was partitioned between H2O
(25 mL) and CH2Cl2 (25 mL). The CH2Cl2 phase was evaporated
under reduced pressure to give a residue that was separated by PTLC
using CHCl3ꢀMeOH (30:1) to afford a product (0.9 mg): [R]20D ꢀ6.1
(c 0.20, MeCN); CD (MeCN) 230 (Δε ꢀ0.01), 241 (Δε ꢀ0.21), 257
1
(Δε þ0.18), 274.5 (Δε ꢀ0.22) nm. These data and the H NMR
(CDCl3, 300 MHz) and ESIMS data of the product were completely
consistent with those of the co-occurring (ꢀ)-medioresinol.33 Similarly,
11 (7.6 mg) was hydrolyzed to afford (ꢀ)-medioresinol (0.8 mg).
Compounds 12ꢀ18 were hydrolyzed using the same procedure to
produce a colorless gum: [R]20D ꢀ7.0 (c 0.10, MeCN); CD (MeCN)
209 (Δε ꢀ1.54), 232 (Δε 0.00), 241 (Δε ꢀ0.07), 254 (Δε þ0.12), 270
(Δε ꢀ0.12) nm. These data, and the 1H NMR (Me2CO-d6, 300 MHz)
and ESIMS data of the product, were identical to those of the co-
occurring (ꢀ)-syringaresinol.26
’ ASSOCIATED CONTENT
S
Supporting Information. Copies of IR, MS, 1D and/or
b
2D NMR, and CD spectra for compounds 1ꢀ22. NMR spectra
of compounds 3a and acetonide derivatives of 10ꢀ22
(10aꢀ22a). Table S1, NMR data (δ) for 10aꢀ15a. Table S2,
1H NMR data (δ) for 19aꢀ22a. This can be accessed free of
charge via the Internet at http://pubs.acs.org.
(ꢀ)-(700R,800S)-400,5,7-Trihydroxy-30,50-dimethoxy-40,800-oxyflavo-
nolignan-700,900-diol (19): yellow, amorphous powder; [R]20D ꢀ61.1 (c
0.03, MeOH); UV (MeOH) λmax (log ε) 209 (4.19), 270 (3.70), 345
(3.89) nm; CD (MeCN) 239 (Δε ꢀ0.44), 266 (Δε þ0.07), 283
(Δε ꢀ0.03), 322 (Δε þ0.09), 362 (Δε ꢀ0.13) nm; Rh2(OCOCF3)4-
induced CD (CH2Cl2) 323 (Δε ꢀ0.08), 356 (Δε ꢀ0.04), 386
(Δε ꢀ0.01), 410 (Δε ꢀ0.02), 435 (Δε 0.00), 469 (Δε ꢀ0.03); IR νmax
’ AUTHOR INFORMATION
Corresponding Author
*Tel: 86-10-83154789. Fax: 86-10-63017757. E-mail: zhuchenggen@
imm.ac.cn and shijg@imm.ac.cn.
3436, 2923, 1653, 1615, 1505, 1461, 1355, 1263, 1160, 1118, 838 cmꢀ1
;
1H NMR (DMSO-d6, 300 MHz) data, see Table 6; 13C NMR (DMSO-d6,
125 MHz) data, see Table 6; (ꢀ)-ESIMS m/z 495 [M ꢀ H]ꢀ.
(ꢀ)-(700S,800S)-400,5,7-Trihydroxy-30,50-dimethoxy-40,800-oxyflavono-
lignan-700,900-diol (20): yellow, amorphous powder; [R]20D ꢀ20.0 (c 0.02,
MeOH); UV (MeOH) λmax (logε) 202 (4.17), 272 (3.30), 334 (3.11) nm;
CD (MeCN) 221 (Δε þ0.21), 246 (Δε ꢀ0.19), 268 (Δε þ0.05), 286
(Δε ꢀ0.01), 318 (Δε þ0.08), 353 (Δε ꢀ0.07) nm; Rh2(OCOCF3)4-
induced CD (CH2Cl2) 308 (Δε ꢀ0.19), 362 (Δε þ0.07), 424 (Δε
þ0.01), 452 (Δε þ0.06), 469 (Δε þ0.05); IR νmax 3204, 2947, 1657,
1618, 1594, 1500, 1454, 1365, 1242, 1165, 1120, 1050, 839 cmꢀ1; 1H NMR
(DMSO-d6, 600 MHz) data, see Table 6; 13CNMR(DMSO-d6, 150 MHz)
data, see Table 6; (ꢀ)-ESIMS m/z 495 [M ꢀ H]ꢀ.
’ ACKNOWLEDGMENT
Financial support from the National Natural Sciences Founda-
tion of China (NNSFC; grant nos. 30825044 and 20932007) and
the National Science and Technology Project of China (nos.
2009ZX09311-004 and 2009ZX09301-003-4-1) is acknowledged.
’ REFERENCES
(1) Jiangsu New Medical College. Dictionary of Traditional Chinese
Medicine; Shanghai Science and Technology Publishing House: Shang-
hai, 1986; p 2514.
1199
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Journal of Natural Products
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