Dibenzoyl and isoflavonoid glycosides from sophora flavescens: Inhibition of the cytotoxic effect of d -galactosamine on human hepatocyte HL-7702

Article abstract of DOI:10.1021/np400784v

Twelve new dibenzoyl derivatives sophodibenzoside A-L (1-12) and five new isoflavone glycosides (13-17) have been isolated from the roots of Sophora flavescens together with eight known compounds (18-25). Notably, the use of acetic acid-d₄ was required to enable identification of the dibenzoyl glycoside structures. Compounds 1, 2, 13, 14, and 19 exhibited weak inhibition of the cytotoxic effect of d-galactosamine on the human hepatic cell line HL-7702.

Full text of DOI:10.1021/np400784v

Article
pubs.acs.org/jnp
Dibenzoyl and Isoflavonoid Glycosides from Sophora flavescens:
Inhibition of the Cytotoxic Effect of D‑Galactosamine on Human
Hepatocyte HL-7702
Yi Shen, Zi-Ming Feng, Jian-Shuang Jiang, Ya-Nan Yang, and Pei-Cheng Zhang*
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of
Medical Sciences and Peking Union Medical College, Beijing 100050, People’s Republic of China
S
* Supporting Information
ABSTRACT: Twelve new dibenzoyl derivatives sophodiben-
zoside A−L (1−12) and five new isoflavone glycosides (13−
17) have been isolated from the roots of Sophora flavescens
together with eight known compounds (18−25). Notably, the
use of acetic acid-d4 was required to enable identification of the
dibenzoyl glycoside structures. Compounds 1, 2, 13, 14, and
19 exhibited weak inhibition of the cytotoxic effect of D-
galactosamine on the human hepatic cell line HL-7702.
he perennial shrub Sophora flavescens Ait. (Leguminosae)
Tis distributed widely throughout East Asia. In the People’s
Republic of China, the roots of this plant are known as “ku
shen”. It is commonly used in traditional Chinese medicine
(TCM) as an antipyretic and diuretic agent and has been used
for the treatment of skin and gynecological diseases.
Pharmacological investigations indicated that S. flavescens can
be beneficial for mental health, and that it has anti-
inflammatory, anthelmintic, free radical scavenging, and
antimicrobial activity.1−4 Previous chemical studies on S.
flavescens revealed that quinolizidine alkaloids and flavonoids
are the main chemical components, and these are usually
regarded as the active constituents.5−8 Recent reports suggested
that S. flavescens possessed hepatoprotective properties and was
active against the hepatitis B virus, with an alkaloid, oxymatrine,
contributing to this activity.9−12 As a continuation of our efforts
RESULTS AND DISCUSSION
■
to explore new compounds with hepatoprotective activity, a
series of new dibenzoyl derivatives (1−12) and isoflavonoid
glycosides (13−17) were isolated from S. flavescens, together
with eight known compounds (18−25). In the course of NMR
experiments directed toward confirming the structures of the
dibenzoyl glycosides, different deuterated solvents had to be
examined to obtain the clearest NMR spectra. Ultimately, acetic
acid-d4 was found the most appropriate deuterated solvent, and
a possible mechanism underlying this result is discussed. Some
compounds were assessed for inhibition of the cytotoxic effect
of D-galactosamine on the human hepatic cell line HL-7702.
Compound 1 was obtained as a yellow powder, and its
molecular formula was established as C26H30O15 by HRESIMS
{m/z 605.1479 [M + Na]+ (calcd for 605.1477)}. The IR
spectrum of 1 revealed the presence of hydroxy (3355 cm−1)
and carbonyl (1663 cm−1) groups. In the H NMR spectrum
1
(Table 1), two sets of typical ABX systems were present at δH
7.45 (1H, d, J = 8.5 Hz), 6.79 (1H, d, J = 2.0 Hz), and 6.62
(1H, dd, J = 8.5, 2.0 Hz) and 7.02 (1H, d, J = 8.5 Hz), 7.51
(1H, d, J = 2.0 Hz), and 7.49 (1H, dd, J = 8.5, 2.0 Hz),
Received: September 30, 2013
Published: December 2, 2013
© 2013 American Chemical Society and
American Society of Pharmacognosy
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dx.doi.org/10.1021/np400784v | J. Nat. Prod. 2013, 76, 2337−2345

Journal of Natural Products
Article
1
Table 1. H NMR (500M) Spectroscopic Data (δ in ppm, J in Hz) for Compounds 1−6 in Acetic Acid-d4
position
1
2
3
4
5
6
3′
5′
6′
2″
3″
5″
6″
glc-1‴
2‴
3‴
4‴
5‴
6‴a
6‴b
6.79, d (2.0)
6.75, brs
6.70, d (2.0)
6.80, d (2.5)
6.62, dd (8.5, 2.5)
7.47, d (8.5)
7.96, d (8.5)
7.04, d (8.5)
7.04, d (8.5)
7.96, d (8.5)
5.15, d (7.5)
3.73, m
6.76, d (2.0)
6.61, dd (8.5, 2.0)
7.47, d (8.5)
7.95, d (8.5)
7.04, d (8.5)
7.04, d (8.5)
7.95, d (8.5)
5.15, d (7.5)
3.74, m
6.72, d (2.0)
6.65, d (8.5)
7.47, d (8.5)
7.94, d (8.5)
7.07, d (8.5)
7.07, d (8.5)
7.94, d (8.5)
5.20, d (7.5)
3.72, m
6.62, dd (8.5, 2.0)
7.45, d (8.5)
6.60, d (8.5)
7.45, d (8.5)
7.51, brs
6.60, dd (8.5, 2.0)
7.45, d (8.5)
7.51, d (2.0)
7.51, d (2.0)
7.02, d (8.5)
7.49, dd (8.5, 2.0)
5.16, d (7.5)
3.72, m
7.01, d (8.0)
7.49, overlapped
5.15, d (7.5)
3.73, m
7.01, d (8.5)
7.48, dd (8.5, 2.0)
5.21, d (7.5)
3.72, m
3.78, m
3.78, m
3.81, m
3.79, m
3.76, m
3.77, t (9.0)
3.64, t (9.0)
3.73, m
3.67, t (9.0)
3.86, m
3.62, t (9.0)
3.81, m
3.69, t (9.0)
3.72, m
3.68, m
3.63, m
3.86, m
3.80, m
4.16, d (9.5)
3.85, m
4.06, d (11.5)
3.70, m
4.01, d (12.5)
3.88, dd (12.5, 5.0)
4.16, d (10.0)
3.85, m
4.06, d (11.5)
3.70, m
4.00, d (12.0)
3.83, dd (12.0, 5.5)
xyl
api
xyl
api
1′′′′
2′′′′
3′′′′
4′′′′
4.45, d (7.5)
3.46, dd (7.5, 9.0)
3.60, t (9.0)
3.76, m
5.09, brs
4.44, d (7.5)
3.46, dd (7.5, 9.0)
3.59, t (9.0)
3.75, m
5.10, d (2.0)
4.10, d (2.0)
4.08, brs
3.99, d (10.0)
3.88, d (10.0)
3.78, s
3.99, d (10.5)
3.90, d (10.5)
3.77, m
5′′′′
4.00, dd (11.5, 5.0)
3.28, dd (11.5, 10.0)
3.95, s
3.98, dd (11.5, 5.5)
3.28, t (11.5)
3.89, s
4″-OCH3
3.95, s
3.96, s
3.89, s
3.90, s
Figure 1. Key HMBC correlations of compounds 1, 7, and 16.
characteristic of two trisubstituted benzene rings. A methoxy
resonance (δH 3.96, 3H, s) and two anomeric proton
resonances at δH 5.16, (1H, d, J = 7.5 Hz, glc-1-H) and 4.45
(1H, d, J = 7.5 Hz, xyl-1-H) were also observed. The remaining
proton resonances corresponding to the sugar moieties
appeared at δH 3.27−4.16. The 13C NMR spectrum of 1
showed 26 carbon resonances (Table 3). Of these carbon
resonances, 12 were attributed to two benzene rings. Two
carbonyl carbon resonances at δC 194.6 and 201.2 were
observed in the downfield region. A methoxy resonance at δC
58.9 and two anomeric carbon resonances from sugar moieties
at δC 102.5 and 106.8 were also observed. The HMBC
experiment (Figure 1) showed correlations from H-6′ to C-2
and from H-2″ and H-6″ to C-1, which suggested two carbonyl
carbons linked to two benzene rings. The methoxy group was
assigned at C-4″ from the correlation of −OCH3 (δH 3.95, s)
with C-4″(δC 156.8). The D-configurations of the xylopyranosyl
and glucopyranosyl moieties were determined by comparison
of the NMR data,13 and GC analysis after acidic hydrolysis and
chiral derivatization of 1.14,15 The β-configurations were
deduced based on the chemical shifts and coupling constants
(glc: J = 7.5 Hz and xyl: J = 7.5 Hz) of the anomeric protons.13
The linkage positions of the two sugar moieties were
established as β-D-xylopyranosyl-(1→6)-β-D-glucopyranosyl
based on the 13C NMR shift values and the HMBC correlations
showing correlation of xyl-H-1 with C-6‴. In addition, the key
HMBC correlation of C-4′ with glc-H-1‴ confirmed that the
glucopyranosyl moiety was located at C-4′ (Figure 1). Thus, 1
was determined to be 2′,3″-dihydroxy-4″-methoxydibenzoyl-4′-
O-β-D-xylopyranosyl-(l→6)-β-D-glucopyranoside and was
named sophodibenzoside A.
Compound 2 showed a quasi-molecular ion at m/z 605.1487
[M + Na]+ in the HRESIMS (calcd for 605.1477),
1
corresponding to the molecular formula C26H30O15. The H
and 13C NMR spectra of 2 were similar to those of 1 with the
exception of the sugar moiety. The 13C NMR spectrum of 2
(Table 3) showed the anomeric carbon at δC 112.4 (api-C-1)
and the other four carbon resonances at δC 83.1, 80.5, 76.8, and
68.1. The 1H NMR spectrum (Table 1) also showed an
anomeric proton at δH 5.09 (1H, br s) and the other proton
resonances at δH 4.08−3.78. These implied the presence of an
apiofuranosyl group in 2 instead of the xylopyranosyl moiety
found in 1. The HMBC spectrum confirmed the linkage
position at C-6‴, based on the observed correlation of C-6‴
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1
Table 2. H NMR (500M) Spectroscopic Data (δ in ppm, J in Hz) for Compounds 7−12 in Acetic Acid-d4
position
7
8
9
10
11
12
3′
5′
6′
2″
5″
6″
6.79, d (2.0)
6.62, dd (8.5, 2.0)
7.45, d (8.5)
7.48, d (2.0)
6.92, d (8.5)
7.52, dd (8.5, 2.0)
5.16, d (8.0)
3.73, m
6.75, d (2.5)
6.60, dd (9.0, 2.5)
7.45, d (9.0)
7.48, d (1.5)
6.92, d (8.5)
7.52, dd (8.5, 1.5)
5.15, d (7.5)
3.73, m
6.70, d (1.5)
6.62, dd (8.5, 1.5)
7.45, d (8.5)
7.47, d (2.0)
6.92, d (8.0)
7.51, d (8.0, 2.0)
5.21, d (7.5)
3.72, m
6.79, d (2.5)
6.62, dd (9.0, 2.5)
7.47, d (9.0)
7.62, d (2.0)
6.96, d (8.0)
7.44, dd (8.0, 2.0)
5.16, d (7.5)
3.73, m
6.70, d (2.5)
6.60, dd (9.0, 2.5)
7.46, d (9.0)
7.62, d (1.5)
6.96, d (7.5)
7.44, dd (7.5, 1.5)
5.21, d (8.0)
3.71, m
6.78, d (2.0)
6.64, dd (9.0, 2.0)
7.46, d (9.0)
7.52, d (2.0)
6.97, d (8.0)
7.38, dd (8.0, 2.0)
5.17, d (7.0)
3.72, m
glc-1‴
2‴
3‴
4‴
5‴
3.80, t (9.0)
3.68, t (9.0)
3.85, m
3.75, m
3.81, t (9.0)
3.68, t (9.0)
3.72, m
3.79, t (9.0)
3.68, m
3.81, t (9.0)
3.77, m
3.63, t (9.0)
3.82, m
3.67, t (9.0)
3.61, m
3.86, m
3.72, m
3.85, m
6‴a
6‴b
4.16, d (10.5)
3.86, m
4.05, d (12.5)
3.69, m
4.01, d (12.0)
3.87, dd (12.0, 5.0)
4.17, d (10.0)
3.85, m
4.00, dd (12.5, 2.0)
3.87, dd (12.5, 5.0)
4.16, d (10.0)
3.85, m
xyl
api
xyl
xyl
1′′′′
2′′′′
3′′′′
4′′′′
4.45, d (7.0)
3.46, dd (7.0, 9.0)
3.60, t (9.0)
3.76, m
5.09, d (2.0)
4.07, d (2.0)
4.45, d (7.0)
3.47, dd (9.0,7.0)
3.60, t (9.0)
3.75, m
4.43, d (7.5)
3.45, dd (9.0,7.5)
3.55, m
4.00, d (10.0)
3.88, d (10.0)
3.75, s
3.70, m
5′′′′
4.00, dd (11.5, 5.5)
3.28, t (11.5)
4.00, dd (11.5, 5.0)
3.28, dd (11.5, 10.0)
3.95, s
3.96, m
3.27, t (11.5)
3″-OCH3
3.95, s
3″,4″-OCH2O-
6.10, s
6.10, s
6.10, s
(δC 70.4) with H-1′′′′. The configurations of the apiofuranosyl
and glucopyranosyl groups were determined by the same
methods as 1.14,15 Thus, the structure of compound 2 was
elucidated as 2′,3″-dihydroxy-4″-methoxydibenzoyl-4′-O-β-D-
apiofuranosyl-(l→6)-β-D-glucopyranoside, and it was named
sophodibenzoside B.
Compound 3 had the molecular formula C21H22O11 by
analysis of its HRESIMS, which gave a quasi-molecular ion at
m/z 473.1076 [M + Na]+. The 1H and 13C NMR resonances of
the aglycone of 3 were similar to those of 1 (Tables 1 and 3),
with the only differences arising due to the absence of a pentose
moiety. This is supported by the presence of a glc-C-6‴ (δC
64.2) resonance in 3 instead of the corresponding glc-C-6‴ (δC
71.7) resonance found in 1. Thus, compound 3 was elucidated
to be 2′,3″-dihydroxy-4″-methoxydibenzoyl-4′-O-β-D-glucopyr-
anoside and was named sophodibenzoside C.
The molecular formula of compound 4 was established as
C26H30O14 by the HRESIMS {[M + Na]+ ion at m/z
589.1539}. Comparison of the NMR data of 4 with those of
1 (Tables 1 and 3) indicated the absence of an aromatic
hydroxy resonance in 4. In the 1H NMR spectrum of 4 (Table
1), a set of AA′BB′ resonances at δH 7.96 (2H, d, J = 8.5 Hz)
and 7.04 (2H, d, J = 8.5 Hz) replaced the corresponding ABX
system arising from ring B of 1. Therefore, the structure of 4
was elucidated as 2′-hydroxy-4″-methoxydibenzoyl-4′-O-β-D-
xylopyranosyl-(l→6)-β-D-glucopyranoside, and it was named
sophodibenzoside D.
Compounds 5 and 6 have the same aglycone moiety as 4,
exhibiting a 2′-hydroxy-4″-methoxydibenzoyl-4′-O-substitution
pattern, based on comparison of their NMR spectra (Tables 1
and 3). Furthermore, the sugar moieties were determined to be
the same for 5 and 2 and for 6 and 3. Thus, these compounds
were assigned the structures 2′-hydroxy-4″-methoxydibenzoyl-
4′-O-β-D-apiofuranosyl-(l→6)-β-D- glucopyranoside (5) and 2′-
hydroxy-4″-methoxydibenzoyl-4′-O-β-D-glucopyranoside (6).
They were named sophodibenzoside E and F, respectively.
Compound 7 was obtained as a yellow powder, and its
HRESIMS showed a quasi-molecular ion at m/z 603.1332 [M
+ Na]+, corresponding to the molecular formula C26H28O15.
The IR, UV, and NMR spectra permitted assignment of the
structure as a dibenzoyl glycoside. Comparison of the NMR
spectra of 7 and 1 showed that the differences between these
two compounds were due to the substituents on ring B. The
3″-hydroxy-4″-methoxy arrangement in 1 was replaced in 7
with a methylenedioxy group with resonances at δH 6.10 (2H,
s) and δC 105.9, suggesting the C-3″, C-4″dioxolane moiety.
This was supported by the HMBC experiment (Figure 1), in
which the correlations of the methylenedioxy protons with C-
3″ (δC 152.2) and C-4″ (δC 157.1) were present. With the
exception of this dioxolane moiety, the remaining moieties of 7
were in accord with those of 1 based on the spectroscopic data
(Tables 2 and 3) and chemical analysis. The structure of
compound 7 was thus elucidated as 2′-hydroxy-3″,4″-
methylenedioxydibenzoyl-4′-O-β-D-xylopyranosyl-(l→6)-β-D-
glucopyranoside and named sophodibenzoside G. With the use
of similar identification methods, compounds 8 and 9 were
readily defined as 2′-hydroxy-3″,4″-methylenedioxydibenzoyl-
4′-O-β-D-apiofuranosyl-(l→6)-β-D-glucopyranoside and 2′-hy-
droxy-3″,4″-methylenedioxydibenzoyl-4′-O-β-D-glucopyrano-
side, respectively. They were named sophodibenzoside H and I,
respectively.
The molecular formula of compound 10 was established as
C26H30O15 by the HRESIMS ion at m/z 605.1461 [M + Na]+.
Most of its spectroscopic data and chemical characteristics were
1
in accord with 1, including UV, IR, MS, H NMR, and 13C
NMR data. The ABX system at δH 7.62 (1H, d, J = 2.0 Hz),
6.96 (1H, d, J = 8.0 Hz), and 7.44 (1H, dd, J = 8.0, 2.0 Hz) on
the B-ring was still present in the 1H NMR spectrum (Table 2).
However, the HMBC spectrum led to assignment of the
methoxy group at C-3″, according to the correlations of δH 3.95
(3H, s) and 6.96 with δC 151.2. The hydroxy group was
unambiguously assigned at C-4″, according to the correlation of
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Journal of Natural Products
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Table 3. 13C NMR (125 M) Spectroscopic Data (δ in ppm, J in Hz) for Compounds 1−12 in Acetic Acid-d4
position
1
2
3
4
5
6
7
8
9
10
11
12
1
194.6, C 194.6, C 194.5, C 194.3, C 194.1, C 194.9, C 193.9, C
201.2, C 201.2, C 201.2, C 201.0, C 201.0, C 200.7, C 200.7, C
115.7, C 115.7, C 115.7, C 115.6, C 115.4, C 115.6, C 115.6, C
168.5, C 168.6, C 168.6, C 168.6, C 168.5, C 168.6, C 168.6, C
193.9, C
200.8, C
115.6, C
168.7, C
193.8, C
200.8, C
115.6, C
168.6, C
194.4, C 194.3, C 194.8, C
201.2, C 201.2, C 201.1, C
115.7, C 115.7, C 115.5, C
168.6, C 168.6, C 168.0, C
2
1′
2′
3′
107.6,
CH
107.6,
CH
107.4,
CH
107.5,
CH
107.4,
CH
107.3,
CH
107.6,
CH
107.5,
CH
107.4,
CH
107.6,
CH
107.4,
CH
107.3,
CH
4′
5′
168.0, C 168.1, C 168.0, C 168.0, C 167.9, C 167.9, C 168.0, C
168.2, C
168.1, C
168.0, C 168.0, C 167.8, C
112.8,
CH
112.8,
CH
112.5,
CH
112.8,
CH
112.2,
CH
112.6,
CH
112.8,
CH
112.8,
CH
112.6,
CH
112.8,
CH
112.5,
CH
112.7,
CH
6′
137.5,
CH
137.5,
CH
137.6,
CH
137.4,
CH
137.2,
CH
137.3,
CH
137.4,
CH
137.4,
CH
137.5,
CH
137.5,
CH
137.5,
CH
137.3,
CH
1″
2″
129.6, C 129.5, C 129.6, C 129.0, C 128.9, C 128.5, C 130.9, C
130.9, C
130.9, C
130.3, C 128.7, C 128.5, C
118.2,
CH
118.2,
CH
118.2,
CH
135.7,
CH
135.6,
CH
135.7,
CH
111.1,
CH
111.1,
CH
111.6,
CH
114.0,
CH
113.9,
CH
118.6,
CH
3″
149.8, C 149.7, C 149.8, C 117.7,
CH
117.5,
CH
117.7,
CH
152.2, C
152.2, C
152.2, C
151.2, C 151.2, C 148.1, C
4″
5″
156.8, C 156.8, C 156.8, C 168.5, C 168.5, C 168.6, C 157.1, C
157.2, C
157.2, C
156.4, C 156.4, C 155.3, C
114.1,
CH
114.1,
CH
114.1,
CH
117.7,
CH
117.5,
CH
117.7,
CH
111.6,
CH
111.6,
CH
111.1,
CH
118.2,
CH
118.2,
CH
118.8,
CH
6″
128.1,
CH
128.1,
CH
128.1,
CH
135.7,
CH
135.6,
CH
135.7,
CH
131.5,
CH
131.5,
CH
131.5,
CH
128.8,
CH
130.1,
CH
128.3,
CH
glc-1‴
102.5,
CH
102.6,
CH
102.4,
CH
102.4,
CH
102.4,
CH
102.2,
CH
102.5,
CH
102.6,
CH
102.4,
CH
102.5,
CH
102.4,
CH
102.2,
CH
2‴
3‴
4‴
5‴
6‴
76.4, CH 76.5, CH 76.5, CH 76.4, CH 76.5, CH 76.0, CH 76.4, CH 76.5, CH 76.4, CH 76.5, CH 76.4, CH 76.4, CH
79.4, CH 79.5, CH 79.2, CH 79.4, CH 79.2, CH 78.8, CH 79.4, CH 79.5, CH 79.1, CH 79.5, CH 79.1, CH 79.4, CH
73.1, CH 73.2, CH 72.7, CH 72.7, CH 72.9, CH 72.6, CH 73.0, CH 73.2, CH 72.7, CH 73.1, CH 72.7, CH 71.3, CH
78.5, CH 78.5, CH 79.2, CH 78.4, CH 78.3, CH 79.1, CH 78.5, CH 78.5, CH 79.2, CH 78.5, CH 79.2, CH 78.5, CH
71.7,
CH2
70.4,
CH2
64.2,
CH2
71.7,
CH2
70.2,
CH2
64.0,
CH2
71.7, CH2 70.0, CH2 64.2, CH2 71.8,
CH2
64.2,
CH2
71.7,
CH2
xyl
api
xyl
api
xyl
api
Xyl
Xyl
1′′′′
106.8,
CH
112.4,
CH
106.7,
CH
112.2,
CH
106.8,
CH
112.4,
CH
106.8,
CH
106.5,
CH
2′′′′
3′′′′
4′′′′
76.4, CH 80.5, CH
79.0, CH 83.1, C
76.4, CH 80.5, CH
79.0, CH 83.0, C
76.5, CH 80.5, CH
79.0, CH 83.1, C
72.7, CH 76.8, CH2
76.5, CH
79.0, CH
72.8, CH
76.5, CH
79.0, CH
72.7, CH
72.7, CH 76.8,
CH2
73.0, CH 76.3,
CH2
5′′′′
67.9,
CH2
68.1,
CH2
67.9,
CH2
67.9,
CH2
67.9, CH2 68.1, CH2
68.0,
CH2
67.9,
CH2
3″-OCH3
4″-OCH3
3″,4″-OCH2O-
58.8,
CH3
58.8,
CH3
58.9,
CH3
58.9,
CH3
58.9,
CH3
58.3,
CH3
58.2,
CH3
58.5,
CH3
105.9,
CH2
105.9,
CH2
105.9,
CH2
δH 7.44 with δC 156.4. Thus, the structure of compound 10 was
determined to be 2′,4″-dihydroxy-3″-methoxydibenzoyl-4′-O-β-
D-xylopyranosyl-(l→6)-β-D-glucopyranoside, and it was named
sophodibenzoside J.
Compounds 11 and 12 were identified as 2′,4″-dihydroxy-3″-
methoxydibenzoyl-4′-O-β-D-glucopyranoside (sophodibenzo-
side K) and 2′,3″,4″-trihydroxydibenzoyl-4′-O-β-D-xylopyrano-
syl-(l→6)-β-D-glucopyranoside (sophodibenzoside L), respec-
tively.
It is worth noting that dibenzoyl compounds are not only
potential inhibitors of human carboxylesterases, but are also
standard building blocks in the field of organic synthesis.16−19
With the exception of three dibenzoyl aglycones,20−22 no such
glycosidic compounds have been isolated from natural sources.
The structures of the three known dibenzoyl aglycones were
identified based on their NMR spectra in common deuterated
solvents. However, for the dibenzoyl glycosides with a C-2′
hydroxy group, standard NMR techniques became problematic.
Typical deuterated solvents, such as the dipolar aprotic solvent
DMSO-d6, protic methanol-d4, aprotic pyridine-d5, acetone-d6,
and a mixture of D2O and DMSO-d6, did not allow for the
collection of quality NMR spectra: the proton splitting patterns
1
were poorly resolved in the H NMR spectrum and some
carbon resonances were absent in the 13C NMR spectra
(Figures S103−S105 and S110, panels A and B, of the
Supporting Information). Acid hydrolysis and methylation were
used to clarify the chemical structures of these compounds. The
aglycone 1a was thus obtained from 1, while 4a was derived
from 4 by acid hydrolysis. NMR spectra of these compounds
were then recorded in methanol-d4 and acetone-d6, respectively,
but no improvement was observed in the quality of the spectra
(Figures S106−S108 of the Supporting Information). Next, the
tetra-O-methyl ether of aglycone (1b) was obtained from 1a
through methylation with dimethyl sulfate in a solution of
KOH and acetone. The NMR spectra of 1b recorded in
DMSO-d6 were well-resolved and -integrated (Figure S110C of
the Supporting Information). On the basis of its structural
features, hydrogen bonding was presumed to be the main
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factors influencing the spectroscopic behavior. Thus, the
influence of solvents facilitating the breaking of hydrogen
bond between the C-2′ hydroxy group and proximal carbonyl
groups were examined. In trifluoroacetic acid-d1, the resolution
Compound 13 gave a quasi-molecular ion [M + Na]+ at m/z
601.1550 in HRESIMS, responding to a molecular formula of
C27H30O14. The UV spectrum showed absorption at 254 and
290 nm. In the 1H NMR spectrum of 13 (Table 4), one typical
singlet was observed at δH 8.35 (1H, s, H-2), as was a set of
protons in an ABX spin system at δH 7.25 (1H, d, J = 2.0 Hz),
8.07 (1H, d, J = 9.0 Hz), and 7.16 (1H, dd, J = 9.0, 2.0 Hz).
Additional resonances were observed at δH 7.08 (1H, s) and
6.98 (2H, br s), along with two sets of sugar resonances with
anomeric protons at δH 5.07 (1H, d, J = 7.5 Hz) and 4.82 (1H,
d, J = 3.0 Hz). A methoxy group was also observed at δH 3.81
(3H, s). The 13C NMR spectrum of 13 showed 27 carbon
resonances (Table 5). All of these resonances were in good
agreement with an isoflavone glycoside structure.23 The types
and configuration of the sugars were determined by NMR data
comparison and GC analysis after acidic hydrolysis and chiral
derivatization.14,15 The linkages for these moieties were
established based on HMBC experiments, in which the
correlations from glc-H-1″(δH 5.07) to C-7 (δC 161.8)
suggested that the sugar moiety was located at C-7. The
methoxy group was assigned at C-4′ from the correlations
−OCH3 (δH 3.81, 3H, s) and H-6′ to C-4′ (δC 148.1). Thus,
the structure of 13 was assigned as 3′-hydroxy-4′-methoxyiso-
flavone-7-O-β-D-apiofuranosyl-(l→6)-β-D-glucopyranoside.
The HRESIMS of compound 14 gave a quasi-molecular ion
[M + Na]+ at 601.1547, appropriate for a molecular formula of
C27H30O14. The IR and UV spectra suggested that 14 was also
an isoflavone glycoside. However, comparison between the
NMR spectra of 14 and 13 showed two key differences
between these compounds (Tables 4 and 5). These differences
arose from the interchange of B-ring hydroxy and methoxy
group and from the presence of a xylopyranosyl moiety instead
1
was greatly enhanced in the HNMR spectrum. However, the
resonances from the xylopyranosyl moiety in 1 disappeared due
to hydrolysis by the strong acid trifluoroacetic acid-d1 (Figure
S109 of the Supporting Information). Finally, the NMR
experiments were conducted in the weak acid, acetic acid-d4.
As expected, all the NMR resonances were observed, including
the split proton resonances and the aromatic and carbonyl
carbon resonances (Figure S110D of the Supporting
Information). It is possible that when deuterated acids, such
as trifluoroacetic acid-d1 or acetic acid-d4 are employed as
solvents, the hydrogen bonds are disrupted and the activated
hydrogen of the C-2′ hydroxy group is exchangeable with
deuterium. In other solvents, such as DMSO-d6, acetone-d6,
methanol-d4, and D2O + DMSO-d6, slow rotation due to
hydrogen bonds between the C-2′ hydroxy group and the C-1
and C-2 carbonyls (Figure 2) would give poorly resolved NMR
spectra.
Figure 2. The possible solution structures of sophodibenzosides.
1
Table 4. H NMR (500M) Spectroscopic Data (δ in ppm, J in Hz) for Compounds 13−17 in DMSO-d6
position
13
14
15
16
17
2
5
8.35, s
8.40, s
8.39, s
8.28, s
8.38, s
8.07, d (9.0)
7.16, dd (9.0, 2.0)
7.25, d (2.0)
7.08, brs
8.08, d (8.5)
8.08, d (9.0)
7.91, d (9.0)
8.04, d (9.0)
6
7.20, dd (8.5, 2.0)
7.29, d (2.0)
7.16, dd (9.0, 2.0)
7.25, d (2.0)
6.91, dd (9.0, 2.0)
6.82, d (2.0)
7.14, dd (9.0, 2.0)
7.22, d (2.0)
8
2′
7.20, d (2.0)
7.20, d (2.0)
7.15, d (2.0)
3′
6.95, s
5′
6′
6.98, brs
6.84, d (8.5)
7.02, dd (8.5, 2.0)
5.05, d (7.0)
3.34, m
6.84, d (8.0)
7.00, dd (8.0, 2.0)
5.07, d (7.0)
3.31, m
6.97, d (8.0)
7.05, dd (8.0, 2.0)
5.04, d (7.0)
3.29, m
6.98, brs
6.76, s
glc-1″
2″
3″
4″
5″
6″a
6″b
5.07, d (7.5)
3.32, m
4.75, d (7.5)
3.10, m
3.33, m
3.31, m
3.33, m
3.25, t (9.0)
3.07, t (9.0)
3.30, m
3.30, m
3.14, m
3.20, m
3.14, m
3.11, m
3.66, m
3.65, m
3.66, m
3.63, m
3.90, d (11.5)
3.48, dd (11.5, 7.5)
api
3.96, d (11.0)
3.61, dd (11.0, 6.5)
xyl
3.90, d (9.0)
3.48, m
3.71, d (10.5)
3.41, m
3.87, d (10.0)
3.45 m
api
api
1‴
2‴
3‴
4‴
4.82, d (3.0)
3.80, m
4.19, d (7.5)
3.00, m
4.82, d (3.0)
3.80, m
4.80, d (3.0)
3.76, m
3.09, m
3.95, d (9.5)
3.62, d (9.5)
3.38, s
3.31, m
3.94, d (9.0)
3.62, d (9.0)
3.34, s
3.91, d (9.5)
3.58, d (9.5)
3.35, s
5‴
3.70, m
2.97, m
3.81, s
3′-OCH3
4′-OCH3
3.81, s
3.81, s
3.78, s
3′,4′-OCH2O-
6.04, s
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Table 5. 13C NMR (125M) Spectroscopic Data (δ in ppm, J in Hz) for Compounds 13−17 in DMSO-d6
position
13
14
15
16
17
2
154.0, CH
125.0, C
175.1, C
127.5, CH
115.9, CH
161.8, C
104.1, CH
157.5, C
119.0, C
124.0, C
116.9, CH
146.5, C
148.1, C
112.5, CH
120.2, CH
100.5, CH
73.6, CH
77.0, CH
70.5, CH
76.1, CH
68.3, CH2
api
154.0, CH
124.2, C
175.2, C
127.6, CH
115.9, CH
161.8, C
104.1, CH
157.5, C
119.1, C
123.3, C
113.8, CH
147.7, C
147.1, C
115.7, CH
122.0, CH
100.6, CH
73.6, CH
76.9, CH
70.3, CH
76.3, CH
69.1, CH2
xyl
154.0, CH
124.2, C
175.2, C
127.5, CH
115.9, CH
161.8, C
104.1, CH
157.5, C
119.0, C
123.2, C
113.7, CH
147.7, C
147.1, C
115.7, CH
122.0, CH
100.5, CH
73.6, CH
77.0, CH
70.5, CH
76.1, CH
68.3, CH2
api
155.8, CH
120.5, C
175.5, C
127.5, CH
116.1, CH
164.4, C
102.6, CH
158.1, C
116.1, C
113.6, C
148.5, C
102.6, CH
148.2, C
141.3, C
118.5, CH
102.9, CH
73.9, CH
77.2, CH
70.5, CH
77.7, CH
61.4, CH2
154.4, CH
126.0, C
175.0, C
127.4, CH
115.9, CH
161.8, C
104.1, CH
157.4, C
119.0, C
123.8, C
109.6, CH
147.4, C
147.5, C
108.7, CH
122.9, CH
100.5, CH
73.6, CH
77.0, CH
70.5, CH
76.1, CH
68.3, CH2
api
3
4
5
6
7
8
9
10
1′
2′
3′
4′
5′
6′
glc-1″
2″
3″
4″
5″
6″
1‴
2‴
3‴
4‴
109.9, CH
76.4, CH
79.1, C
104.6, CH
73.9, CH
76.9, CH
70.0, CH
66.1, CH2
56.2, CH3
109.9, CH
76.4, CH
79.1, C
109.8, CH
76.4, CH
79.1, C
73.8, CH2
63.7, CH2
73.8, CH2
63.6, CH2
56.2, CH3
73.8, CH2
63.7, CH2
5‴
3′-OCH3
4′-OCH3
3′,4′-OCH2O-
56.2, CH3
55.6, CH3
101.5, CH2
of an apiofuranosyl group as the sugar. This assessment was
supported by NMR data and GC analysis.14,15 The position of
the methoxy group was assigned at C-3′ by the HMBC
correlations of −OCH3 (δH 3.81, 3H, s) and H-5′ (δH 6.84, 1H,
d, J = 8.5 Hz) with C-3′ (δC 147.7). Thus, compound 14 was
assigned as 4′-hydroxy-3′-methoxyisoflavone-7-O-β-D-xylopyr-
anosyl-(l→6)-β-D-glucopyranoside.
glucopyranosyl moiety was confirmed to be at C-2′ by
HMBC correlation between glc-H-1″ at δH 4.75 (1H, d, J =
7.5 Hz) and C-2′ (δC 148.5) (Figure 1). The position of the
methoxy group was assigned at C-4′ by the correlation of
−OCH3 and H-6′ with C-4′. The configuration of the
glucopyranosyl group was determined on the basis of coupling
constants (J = 7.5 Hz) and GC analysis after acid hydrolysis
and chiral derivatization of 16.14,15 Thus, compound 16 was
assigned as 5′-hydroxy-4′-methoxyisoflavone-2′-β-D-glucopyra-
noside. The spectroscopic data of compound 17 indicated that
it differed from 13 only in that a methyl was absent, while a
methylenedioxyl moiety appeared in 17. Analysis of the 2D
NMR data, especially the HMBC correlations from the
methylenedioxy to C-3′ (δC 147.4) and C-4′ (δC 147.5),
confirmed that the dioxolane moiety was formed between C-3″
and 4″ on ring B. Thus, compound 17 was determined to be
3′,4′-methylenedioxyisoflavone-7-O-β-D-apiofuranosyl-(l→6)-
β-D-glucopyranoside.
The structures of seven known compounds isolated from the
roots of S. flavescens were also identified by comparison of their
chromatographic and spectroscopic data to the literature data.
The known compounds were 3′,4′-dihydroxyisoflavone-7-O-β-
D-glucopyranoside (18),24 3′-hydroxy-4′-methoxyisoflavone-7-
O-β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside (19),25 4′-
hydroxyisoflavone-7-O-β-D-xylopyranosyl-(1→6)-β-D-glucopyr-
anoside (20),26 4′-hydroxyisoflavone-7-O-β-D-apiofuranosyl-
(1→6)-β-D-glucopyranoside (21),27 4′-methoxyisoflavone-7-
O-β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside (22),25
Compound 15 gave a quasi-molecular ion [M + Na]+ at m/z
601.1546, appropriate for a molecular formula of C27H30O14.
The 1H and 13C NMR spectra (Tables 4 and 5) were similar to
those of 14. The most noticeable difference in 15 was the
presence of an apiofuranosyl moiety and the absence of a
xylopyranosyl group (Tables 4 and 5). This was confirmed by
HMBC experiments and GC analysis after acid hydrolysis and
chiral derivatization.14,15 Thus, 15 was determined to be 4′-
hydroxy-3′-methoxyisoflavone-7-O-β-D-apiofuranosyl-(l→6)-β-
D-glucopyranoside.
Compound 16 gave a quasi-molecular ion [M + Na]+ at m/z
485.1064 in the HRESIMS, appropriate for a molecular formula
of C22H22O11. The IR and UV spectra showed that 16 was an
isoflavonoid glucoside. An ABX spin system [δH 6.82 (1H, d, J
= 2.0 Hz), 7.91 (1H, d, J = 9.0 Hz), and 6.91 (1H, d, J = 9.0, 2.0
Hz)] present in the 1H NMR spectrum (Table 4), was
characteristic of a trisubstituted ring. Aromatic protons at δH
6.95 (1H, s) and 6.76 (1H, s) implied the presence of a
tetrasubstituted benzene B-ring. The 13C NMR spectrum
showed 22 carbon resonances (Table 5). These data indicated
that 16 was distinct from the aforementioned isoflavonoid
glycosides in the position of its glucosidic moiety. The
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(+)-oxysophocarpine (23),28 (+)-dehydromatrine (24),29 and
1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (25).30
Some of the compounds were tested for inhibition of the
cytotoxic effect of D-galactosamine on the human hepatic cell
line HL-7702. Compounds 1, 2, 13, 14, and 19 showed
comparable inhibition activities to the positive control bicyclol,
a hepatoprotective drug. The results suggest that alkaloids of S.
flavescens are not the only active components, but that
dibenzoyl and isoflavonoid glycosides also contribute to its
activity. Recent advances indicate that different compounds
exert their hepatoprotective effects through scavenging
oxidative damage31 and antioxidant properties.32
separated by preparative RP-HPLC, using MeOH−H2O (60:40) as
the mobile phase, to yield 7 (9 mg), 9 (7 mg), 10 (16 mg), and 11 (8
mg). Fraction B was chromatographed over Sephadex LH-20, eluting
with MeOH−H2O (1:2) and further purified by preparative RP-HPLC
[MeOH−H2O (23:77)] to yield compounds 23 (18 mg), 24 (7 mg),
and 25 (12 mg).
Sophodibenzoside A (1): yellow powder; [α]2D0-78 (c 0.05, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3355, 2911, 1663,
1608, 1511, 1441, 1274, 1072, 1048, 1022, 764, 636 cm−1; 1H and 13
C
NMR data, see Tables 1 and 3; ESIMS m/z 605.2 [M + Na]+, 581.3
[M − H]−; HRESIMS m/z 605.1479 [M + Na]+ (calcd for
C26H30O15Na, 605.1477).
Sophodibenzoside B (2): yellow powder; [α]2D0-55 (c 0.05, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3391, 2933, 1661,
1620, 1511, 1441, 1274, 1070, 1018, 765, 637 cm−1; 1H and 13C NMR
data, see Tables 1 and 3; ESIMS m/z 581.0 [M − H]−; HRESIMS m/
z 605.1487 [M + Na]+ (calcd for C26H30O15 Na, 605.1477).
Sophodibenzoside C (3): yellow powder; [α]2D0-42 (c 0.05, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3498, 2911, 1659,
EXPERIMENTAL SECTION
■
General Experimental Procedures. Optical rotations were
measured with a JASCO P-2000 polarimeter. UV spectra were
obtained on a JASCO V-650 spectrophotometer. IR spectra were
recorded on a Nicolet 5700 spectrometer using an FT-IR microscope
transmission method. GC experiments were conducted on an Agilent
7890A instrument. NMR spectra were run on INOVA 500
spectrometers. HRESIMS were obtained using an Agilent 1100 series
LC/MSD TOF from Agilent Technologies. ESI mass spectra were
recorded on an Agilent 1100 series LC/MSD ion trap mass
spectrometer. Column chromatography was performed with macro-
porous resin (Diaion HP-20, Mitsubishi Chemical Corp., Tokyo,
Japan), Rp-18 (50 μm, YMC, Kyoto, Japan), Sephadex LH-20
(Pharmacia Fine Chemicals, Uppsala, Sweden), and silica gel (200−
300 mesh, Qingdao Marine Chemical Inc. Qingdao, People’s Republic
of China). Preparative HPLC was carried out on a Shimadzu LC-6AD
instrument with an SPD-20A detector, using a YMC-Pack ODS-A
column (250 × 20 mm, 5 μm, Japan). HPLC-DAD analysis was
performed using an Agilent 1260 series system (Agilent Technologies,
Waldbronn, Germany) with an Apollo C18 column (250 × 4.6 mm, 5
μm, Grace Davison).
1
1607, 1509, 1445, 1347, 1258, 1189, 1079, 1047, 775, 638 cm−1; H
and 13C NMR data, see Tables 1 and 3; ESIMS m/z 449.0 [M − H]−;
HRESIMS m/z 473.1076 [M + Na]+ (calcd for C21H22O11Na,
473.1054).
Sophodibenzoside D (4): yellow powder; [α]2D0-64 (c 0.1, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3506, 3438, 2918,
1667, 1603, 1510, 1369, 1232, 1082, 1045, 1023, 842, 763, 609 cm−1;
1H and 13C NMR data, see Tables 1 and 3; ESIMS m/z 589.1 [M +
Na]+, 565.3 [M − H]−; HRESIMS m/z 589.1539 [M + Na]+ (calcd
for C26H30O14 Na, 589.1528).
Sophodibenzoside E (5): yellow powder; [α]D20-102 (c 0.02,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax: 3400,
2934, 1658, 1598, 1513, 1426, 1268, 1220, 1170, 1070, 1019, 843, 613
1
cm−1; H and 13C NMR data, see Tables 1 and 3; ESIMS m/z 589.1
[M + Na]+, 565.1 [M − H]−; HRESIMS m/z 589.1546 [M + Na]+
(calcd for C26H30O14Na, 589.1528).
Sophodibenzoside F (6): yellow powder; [α]2D0-56 (c 0.05, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3467, 3396, 3193,
1656, 1613, 1600, 1507, 1261, 1231, 1088, 1035, 997, 878, 839, 782,
663, 621 cm−1; 1H and 13C NMR data, see Tables 1 and 3; ESIMS m/
z 433.1 [M − H]−; HRESIMS m/z 457.1119 [M + Na]+ (calcd for
C21H22O10 Na, 457.1105).
Plant Material. The roots of S. flavescens were collected in
Weichang, Hebei Province, People’s Republic of China, in July 2010.
The plant material was identified by Prof. Lin Ma. A voucher specimen
(ID-5-2438) was deposited at the Institute of Materia Medica, Chinese
Academy of Medical Sciences, Beijing 100050, People’s Republic of
China.
Sophodibenzoside G (7): yellow powder; [α]2D0-62 (c 0.05, MeOH);
UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3356, 2918, 1664,
1614, 1502, 1446, 1250, 1099, 1072, 1044, 926, 767, 633 cm−1; 1H and
13C NMR data, see Tables 2 and 3; ESIMS m/z 603.1 [M + Na]+,
579.3 [M − H]−; HRESIMS m/z 603.1332 [M + Na]+ (calcd for
C26H28O15Na, 603.1320).
Extraction and Isolation. The air-dried powdered plant material
(40 kg) was extracted twice with 70% EtOH under reflux for 2 h. The
resulting crude extract of the plant was extracted sequentially with
petroleum ether, EtOAc, and n-butanol. The n-butanol fraction (760
g) was subjected to chromatography on HP-20 macroporous resin,
eluting with a step gradient, to give six fractions: A (eluted with H2O,
228 g), B (eluted with 15% EtOH-H2O, 150 g), C (eluted with 30%
EtOH-H2O, 75 g), D (eluted with 50% EtOH-H2O, 194 g), E (eluted
with 75% EtOH-H2O, 62 g), and F (eluted with 95% EtOH-H2O, 20
g). Fraction C was chromatographed over Sephadex LH-20 with a
gradient of MeOH (5−100%) to give fractions C1−C22. Fraction C11
(1.5 g) was separated by reversed-phase (RP) preparative HPLC,
using MeOH−H2O (35:65) as the mobile phase, to yield 1 (46 mg), 2
(20 mg), 13 (15 mg), 14 (9 mg), and 15 (7 mg). Fraction C12 (0.8 g)
was separated by RP preparative HPLC, using MeOH−H2O (38:62)
as the mobile phase, to yield 17 (6 mg), 19 (55 mg), 20 (13 mg), and
21 (9 mg). Fractions C14 (0.9 g), C15 (0.5 g), and C16 (0.7 g) were
separated by RP preparative HPLC, using MeOH−H2O (30:70) as the
mobile phase, to obtain 4 (15 mg), 5 (40 mg), 12 (8 mg), 16 (9 mg),
and 18 (8 mg). Fraction D was subjected to a silica gel column (200−
300 mesh, 1.3 kg) and eluted sequentially with CHCl3 containing
increasing amounts of MeOH (1:0, 100:1, 50:1, 30:1, 20:1, 10:1, 5:1,
3:1, and 0:1) to yield 54 fractions (D1−D54). Compound 22 (500
mg) was obtained by recrystallization in MeOH from fraction D19.
Fractions D22−D28 were chromatographed over Sephadex LH-20,
eluting with MeOH−H2O (45%) and then separated by preparative
RP-HPLC, using MeOH−H2O (43:57) as the mobile phase, to yield 3
(12 mg), 6 (35 mg), and 8 (6 mg). Fractions D29−D33 were
Sophodibenzoside H (8): yellow powder; [α]D20-25 (c 0.025,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3354,
2920, 1663, 1618, 1503, 1447, 1251, 1102, 1070, 1036, 927, 768, 635
1
cm−1; H and 13C NMR data, see Tables 2 and 3; ESIMS m/z 603.1
[M + Na]+, 579.1[M − H]−; HRESIMS m/z 603.1347 [M + Na]+
(calcd for C26H28O15Na, 603.1320).
Sophodibenzoside I (9): yellow powder; [α]D20-32 (c 0.025,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3355,
2917, 1664, 1603, 1504, 1446, 1251, 1000, 1075, 1030, 927, 767, 634
1
cm−1; H and 13C NMR data, see Tables 2 and 3; ESIMS m/z 471.1
[M + Na]+; HRESIMS m/z 471.0912 [M + Na]+ (calcd for
C21H20O11Na, 471.0898).
Sophodibenzoside J (10): yellow powder; [α]D20-70 (c 0.05,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3388,
2917, 1626, 1589, 1513, 1430, 1252, 1072, 764, 636 cm−1; 1H and 13
C
NMR data, see Tables 2 and 3; ESIMS m/z 581.3 [M − H]−;
HRESIMS m/z 605.1461 [M + Na]+ (calcd for C26H30O15Na,
605.1477).
Sophodibenzoside K (11): yellow powder; [α]D20-19 (c 0.05,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3356,
1
2919, 1624, 1589, 1513, 1429, 1253, 1075, 1024, 764, 635 cm−1; H
and 13C NMR data, see Tables 2 and 3; ESIMS m/z 473.1 [M + Na] +,
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Article
449.2 [M − H]−; HRESIMS m/z 473.1074 [M + Na]+ (calcd for
C21H22O11Na, 473.1054).
Table 6. Hepatoprotective Effects against D-Galactosamine
Induced Toxicity in HL-7702 cells
a
Sophodibenzoside L (12): yellow powder; [α]D20-39 (c 0.05,
MeOH); UV (MeOH) λmax 278, 330 nm; IR (KBr) νmax 3344,
2914, 1658, 1614, 1501, 1445, 1294, 1262, 1072, 1048, 1049, 1024,
cell survival rate (% of normal)
inhibition (% of control)
normal
control
bicyclol
1
100.0 2.9
46.8 8.7
1
825, 764, 636 cm−1; H and 13C NMR data, see Tables 2 and 3;
ESIMS m/z 591.1 [M + Na]+, 567.1[M − H]−; HRESIMS m/z
b
c
62.5 6.9
29.4
27.1
52.4
36.6
45.8
46.3
567.1347 [M − H]−(calcd for C25H27O15, 567.1355).
d
61.3 4.2
3′-Hydroxy-4′-methoxyisoflavone-7-O-β-D-apiofuranosyl-(1→6)-
β-D-glucopyranoside (13): yellow powder; [α]D20-120 (c 0.001,
MeOH); UV (MeOH) λmax 254, 290 nm; IR (KBr) νmax 3351,
2922, 1623, 1512, 1443, 1266, 1199, 1071, 1024, 852, 825, 763, 661
e
2
74.7 6.5
e
13
66.3 3.5
e
14
71.2 3.4
e
1
cm−1; H and 13C NMR data, see Tables 4 and 5; ESIMS m/z 601.2
19
71.5 5.1
[M + Na]+, 577.1 [M − H]−; HRESIMS m/z 601.1550 [M + Na]+
(calcd for C27H30O14Na, 601.1528).
a
The compounds were tested at 1 × 10−5 M. Results are expressed as
b
means
SD (n = 5). Positive control substance (Beijing Union
c d
4′-Hydroxy-3′-methoxyisoflavone-7-O-β-D-xylopyranosyl-(1→6)-
β-D- glucopyranoside (14): yellow powder; [α]2D0-73 (c 0.03, MeOH);
UV (MeOH) λmax 254, 290 nm; IR (KBr) νmax 3364, 2905, 1623,
1516, 1445, 1264, 1199, 1072, 1048, 1062, 850, 825, 764, 660 cm−1;
1H and 13C NMR data, see Tables 4 and 5; ESIMS m/z 601.2 [M +
Pharmaceutical Factory, purity is 98% by HPLC). p < 0.01. p < 0.05.
e
p < 0.001.
ASSOCIATED CONTENT
* Supporting Information
IR, HRESIMS, and NMR spectra for compounds 1−17. This
material is available free of charge via the Internet at http://
pubs.acs.org.
■
Na]+; HRESIMS m/z 601.1547 [M + Na]+ (calcd for C27H30O14Na,
601.1528).
S
4′-Hydroxy-3′-methoxyisoflavone-7-O-β-D-apiofuranosyl-(1→6)-
β-D- glucopyranoside (15): yellow powder; [α]2D0-70 (c 0.03, MeOH);
UV (MeOH) λmax 254, 290 nm; IR (KBr) νmax 3371, 2932, 1622,
1
1515, 1445, 1263, 1200, 1072, 1045, 851, 636, 610 cm−1; H and 13C
AUTHOR INFORMATION
Corresponding Author
*E-mail: pczhang@imm.ac.cn. Tel: +86-10-63165231. Fax:
+86- 10-63017757.
NMR data, see Tables 4 and 5; ESIMS m/z 579.2 [M + H]+;
HRESIMS m/z 601.1546 [M + Na]+ (calcd for C27H30O14Na,
601.1528).
■
5′-Hydroxy-4′-methoxyisoflavone-2′-β-D-glucopyranoside (16):
yellow powder; [α]D20-20 (c 0.03, MeOH); UV (MeOH) λmax 254,
290 nm; IR (KBr) νmax 3348, 2922, 1622, 1512, 1453, 1288, 1197,
Notes
The authors declare no competing financial interest.
1
1095, 1074, 1045, 836, 786, 634 cm−1; H and 13C NMR data, see
Tables 4 and 5; ESIMS m/z 461.4 [M − H]−; HRESIMS m/z
ACKNOWLEDGMENTS
485.1064 [M + Na]+ (calcd for C22H22O11Na, 485.1054).
■
The research described in this publication was supported by the
National Science and Technology Project of People’s Republic
of China (Grant 2011ZX09307-002-01).
3′,4′-Methylenedioxyisoflavone-7-O-β-D-apiofuranosyl-(1→6)-β-
D-glucopyranoside (17): yellow powder; [α]2D0-69 (c 0.02, MeOH);
UV (MeOH) λmax 254, 290 nm; IR (KBr) νmax 3382, 2919, 2885,
1621, 1502, 1441, 1250, 1197, 1069, 1041, 926, 855, 815, 652 cm−1;
1H and 13C NMR data, see Tables 4 and 5; ESIMS m/z 577.2 [M +
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