Diarylheptanoid sulfates and related compounds from myrica rubra bark

Article abstract of DOI:10.1021/np300212c

Three new diarylheptanoids, myricanol 11-sulfate (1), juglanin B 11-sulfate (2), and myricanone 5-O-(6′-O-galloyl)glucoside (3), were isolated from the bark of Myrica rubra. Compounds 1 and 2 were characterized as diarylheptanoid sulfates on the basis of spectroscopic analyses. The antioxidative activities of the fractionated extracts and isolated compounds were estimated by the oxygen radical absorbance capacity (ORAC) and superoxide dismutase (SOD)-like activity assays. The major isolate, myricitrin (4), displayed a high ORAC value and moderate SOD-like activity (13 198 μmol TE (Trolox equivalent)/g and IC₅₀ 127.5 μg/mL, respectively), which might explain the potent antioxidative activity of this material.

Full text of DOI:10.1021/np300212c

Note
pubs.acs.org/jnp
Diarylheptanoid Sulfates and Related Compounds from Myrica rubra
Bark
Morio Yoshimura, Saori Yamakami, Yoshiaki Amakura,* and Takashi Yoshida
College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan
*
S Supporting Information
ABSTRACT: Three new diarylheptanoids, myricanol 11-sulfate (1), juglanin B
1
1-sulfate (2), and myricanone 5-O-(6′-O-galloyl)glucoside (3), were isolated
from the bark of Myrica rubra. Compounds 1 and 2 were characterized as
diarylheptanoid sulfates on the basis of spectroscopic analyses. The antioxidative
activities of the fractionated extracts and isolated compounds were estimated by
the oxygen radical absorbance capacity (ORAC) and superoxide dismutase
(
SOD)-like activity assays. The major isolate, myricitrin (4), displayed a high
ORAC value and moderate SOD-like activity (13 198 μmol TE (Trolox
equivalent)/g and IC50 127.5 μg/mL, respectively), which might explain the
potent antioxidative activity of this material.
1H NMR spectrum showed a one-proton singlet and ABX
Myrica rubra (Myricaceae) is widely distributed in China,
Taiwan, and Japan, and its bark has been used as a traditional
medicine to treat diarrhea and skin diseases and as an
signals in the aromatic region and an oxygen-bearing methine
(δ 4.71) and six methylene signals in the aliphatic region. Each
chemical shift and coupling pattern showed close resemblance
to those of myricanol (5). In view of the ESIMS data showing it
1
,2
astringent. In previous phytochemical studies, some diary-
3
3
lheptanoids including myricanol (5) and myricanone (6)
4
,5
were isolated from the bark of M. rubra. Their biological
activities such as melanogenesis inhibitory effects, antiandro-
genic activity, and inhibitory effects against NO production in
lipopolysaccharide-activated peritoneal macrophages were also
to be 80 (SO ) mass units larger than 5, compound 1 was
3
5
1
presumed to be a sulfate derivative of 5. Comparison of the H
6
NMR spectra of 1 and 5 showed a downfield shift (+δ 0.76)
H
7
for a proton (H-11) attached to an oxygen-bearing carbon.
reported. In this study, we examined antioxidant components in
the aqueous ethanol extract of M. rubra bark, which exhibited
significant antioxidative activity in screening using oxygen
radical absorbance capacity (ORAC) and superoxide dismutase
13
Similarly, the C NMR resonances of 1 were in good
agreement with those of 5, except for a downfield shift (+δ
C
13
9
.5) for C-11 in the C NMR spectrum. These features
supported 1 as the 11-sulfate of 5. Additionally, this structure
was verified by two- or three-bond correlations between
aromatic protons and aliphatic carbons (and vice versa) in
the HMBC spectrum (Figure 2). The absolute configuration at
C-11 of 1 was determined as R on the basis of a negative
(
SOD)-like activity assays. This paper describes the isolation
and structural elucidation of a new gallate of myricanone
glucoside (3) and two new diarylheptanoid sulfates (1 and 2),
along with the antioxidative activities of the isolates.
After removal of the precipitate formed upon concentration
of an aqueous EtOH extract of M. rubra, the remaining
concentrate was partitioned into n-hexane-, EtOAc-, n-BuOH-,
and water-soluble portions. The precipitate was separated using
a MEGA BOND ELUT C18 cartridge column and subsequent
preparative TLC to yield myricitrin (4), myricanol (5), and
myricanone (6). The EtOAc and n-BuOH extracts were
subjected, respectively, to a combination of chromatography
to furnish compounds 1 and 2 from the n-BuOH extract. The
EtOAc extract afforded 3 and eight known compounds, gallic
specific rotation ([α] −28.6, c 0.5, MeOH) similar to that of
D
3
myricanol (5) ([α] −65.6, c 3.0, CHCl ), in which 11R-
D
3
configuration was determined by X-ray crystallographic
3
analysis.
The sulfated structure of compound 2 was suggested by
HRESIMS data [m/z 407.1181 (calcd for C H O S−H,
2
0
24
7
−1
1
4
07.1170)] and the IR absorption at 1241 cm . The H NMR
spectrum showed an ABX system and two meta-coupled one-
proton resonances [δ 6.66 (d, J = 2.0 Hz) and δ 6.92 (br s)] in
the aromatic proton region, and a methoxy signal (δ 3.83),
along with six methylenes and a methine signal in the aliphatic
region. The aliphatic proton resonances were similar to those of
8
acid (7), myricetin (8), actinidione (9), epigallocatechin 3-O-
9
gallate (10), myricetin 3-O-(2″-O-galloyl)rhamnoside (11),
1
prodelphinidin B-2 3,3′-di-O-gallate (12), and (R)- and (S)-
5
1, including a marked downfield shift (+δ 0.89) of the oxygen-
H
myricanol 5-O-(6′-O-galloyl)glucoside (13, 14).
bearing methine signal (δ 4.84), upon comparison with that of
Myricanol 11-sulfate (1) was obtained as an off-white,
amorphous powder and assigned the molecular formula
C H O S from the HRESIMS data [m/z 437.1267 (M −
5
. These spectroscopic characteristics, along with a molecular
2
1
26
8
−
H) ]. The IR spectrum displayed an absorption band at 1231
Received: March 20, 2012
Published: October 15, 2012
−1
cm ascribable to the SO vibration of a sulfate group. The
©
2012 American Chemical Society and
American Society of Pharmacognosy
1798
dx.doi.org/10.1021/np300212c | J. Nat. Prod. 2012, 75, 1798−1802

Journal of Natural Products
Note
Figure 1. Structures of isolated compounds from M. rubra.
Figure 2. HMBC correlations of compounds 1, 2, and 3 (HMBC: H→C).
weight 30 mass units smaller than that of 1, indicated that 2 is a
de-O-methyl analogue of 1. The HMBC spectrum of 2 showed
three-bond long-range couplings from H-7 to two non-
substituted aromatic carbons. Other three-bond correlations
were observed between two aromatic protons and C-7. One of
the aromatic protons (H-5, δ 6.66) correlated with the carbon
resonance at δ 150.2, which was assigned to the methoxy-
bearing C-4 based on long-distance correlations with O-methyl
protons. The aromatic proton at δ 6.92 (H-19) correlated with
a hydroxy-bearing carbon at δ 144.4 (C-3) and to C-1 (δ 128.1)
and C-2 (δ 128.4), indicating structure 2 for this compound.
Further HMBC correlations shown in Figure 2 were also
consistent with the structure of 2. The absolute configuration at
C-11 of 2 was determined as S from its specific rotation ([α]D
+23.2, MeOH), the sign of which was the same as that of (S)-
myricanol ([α]D +37.3, CHCl3). On the basis of these
spectroscopic data, compound 2 was established as juglanin B
11-sulfate.
2
1
799
dx.doi.org/10.1021/np300212c | J. Nat. Prod. 2012, 75, 1798−1802

Journal of Natural Products
Note
Compound 3 was obtained as a pale yellow, amorphous
activity comparable to those of their parent alcohols 5 and 6. In
addition, the SOD-like activity of isolated compounds was
measured by using the SOD-WST kit, and gallic acid (7) and
actinidione (9) were active (IC50 values of 6.26 and 7.93 μg/
mL, respectively, Table 1). Myricitrin (4) and myricetin (8),
powder, and its molecular formula was assigned as C H O
3
4
38 14
−
from HRESIMS data [m/z 669.2163 (M − H) (calcd for
69.2189, C H O −H)]. The H and C NMR spectra of 3
1
13
6
34
38 14
correlated closely with those of (S)-myricanol 5-O-(6′-O-
galloyl)glucoside (14), except for the presence of a carbonyl
carbon signal (C-11, δ 215.5) and the absence of the oxygen-
bearing methine proton in the spectra of 3, indicating that 3 is a
galloylglucoside of myricanone (6). Another difference between
Table 1. SOD-like Activity of Isolated Compounds from M.
rubra
1
compound
myricanol 11-sulfate (1)
IC50 (μg/mL)
the H NMR spectra of 3 and 14 was higher-field shifts of the
786.9
>1000
106.8
aromatic protons H-18 and H-19 (Δδ −0.62 and −0.32,
respectively) for 3. The location of the galloyl group was
evidenced by a deshielded C-6 (δ 4.38, 2H, m), glucosyl
protons, and the HMBC correlations of the galloyl and glucose
methylene protons with a carbonyl carbon signal (δ 168.3) in
the HMBC experiment (Figure 2). Three-bond correlations
were also observed between one anomeric proton and a carbon
at δ 149.9, which was assigned to C-5 by the correlation with
H-7, indicating the glucosylated position at C-5. Structure 3
was chemically substantiated by acid hydrolysis followed by
HPLC analysis to detect an aglycone identical to myricanone
juglanin B 11-sulfate (2)
myricanone 5-O-(6′-O-galloyl)glucoside (3)
myricitrin (4)
127.5
a
myricanol (5)
>100
myricanone (6)
>1000
6.3
gallic acid (7)
myricetin (8)
139.6
7.9
actinidione (9)
epigallocatechin 3-O-gallate (10)
myricetin 3-O-(2″-O-galloyl)rhamnoside (11)
prodelphinidin B-2 3,3′-di-O-gallate (12)
26.1
38.6
19.2
90.5
139.6
(
t 44.7 min) and gallic acid (t 2.9 min). Glucose produced
R
R
(
R)-myricanol 5-O-(6′-O-galloyl)glucoside (13)
S)-myricanol 5-O-(6′-O-galloyl)glucoside (14)
upon the acid hydrolysis of 3 was shown to be in the D-series
(
on the basis of HPLC comparison with an authentic sample of
10
a
D-glucose according to the method reported by Tanaka et al.
Slightly soluble in assay buffer.
From the above spectroscopic data, the structure of 3 was
established as depicted in Figure 1.
which showed strong antioxidative activity in the ORAC
The antioxidative activities of the extracts and compounds
1
1,12
method, showed weak activity (IC : 127.5 and 139.6 μg/mL).
were estimated by the ORAC assay (Figure 3).
The activity
50
Although the diarylheptanoid sulfates (1 and 2) and their
parent alcohols (5 and 6) showed weakened activity, the
galloylated diarylheptanoids (3, 13, and 14) exhibited moderate
activity, which indicated that the presence of the galloyl group
enhances the SOD-like activity.
Alcoholic extracts of M. rubra bark are used as food additives
13
in Japan and are reported to have no toxic effects. The
present data may support the development of M. rubra bark
extract as an antioxidative supplement.
EXPERIMENTAL SECTION
General Experimental Procedures. Optical rotations were
measured on a Jasco P-1030 polarimeter. NMR spectra were recorded
■
1
on a Bruker AVANCE 500 instrument (500 MHz for H and 126
MHz for 13C), with chemical shifts given in δ (ppm) values relative to
those of the solvent [methanol-d (δH 3.30, δ 49.0) and acetone-d
6
4
C
(
δ 2.05, δ 29.8)] on a TMS scale. HRESIMS spectra were obtained
H C
with a Bruker micrOTOF-Q mass spectrometer. Normal-phase HPLC
was conducted in a YMC-pack SIL A-002 column (250 × 4.6 mm i.d.,
YMC Co.) eluted with n-hexane−MeOH−THF−HCOOH
(55:33:11:1) containing oxalic acid (450 mg/L) at a flow rate of 1.5
mL/min. Reversed-phase HPLC was performed with a Shimadzu LC-
0Avp system, using a YMC-pack ODS-AQ column (150 × 2.0 mm
Figure 3. ORAC values of the extracts (A: 80% EtOH ext., B: n-
hexane ext., C: EtOAc ext., D: H O ext., E: ppt.) and constituents (1−
1
2
i.d.) at 40 °C with a flow rate of 0.25 mL/min. The analyses were
1
4, each compound number) of M. rubra. Data are expressed as the
conducted with solvent A, a 100 μM phosphate buffer, and solvent B,
mean ± SD of more than two separate experiments.
CH CN, with a linear gradient of 0−50% B from 0 to 30 min and then
3
5
0−60% B from 30 to 50 min, with monitoring at 280 nm. Column
of the 80% EtOH extract was concentrated in the EtOAc
extract and the precipitate, which were rich in myricitrin (4),
and showed high ORAC values [12 102 and 11 711 μmol TE
chromatography was carried out on Diaion HP-20, MCI-gel CHP20P
Mitsubishi Chemical Co.), Toyopearl HW-40 (coarse grade, Tosoh
Co.), YMC-gel ODS AQ12S50 (YMC Co.), Chromatorex DM1020T
Fuji Silysia Chemical Ltd.), Cosmosil 75C18 (Nacalai Tesque), and
(
(
(
Trolox equivalent)/g, respectively]. Significant activity was
Sephadex LH-20 (GE Healthcare Japan).
exhibited by myricitrin (4) and its aglycone 8 with ORAC
values of 13 198 and 16 120 μmol TE/g, demonstrating that
these compounds contributed most to the activity of the
extract. Notably, even water-soluble diarylheptanoid sulfates (1
and 2) (ORAC values 8680 and 9615 μmol TE/g) showed
Sample and Reagents. The bark of M. rubra was provided by
Nagaoka Perfumery Co. Ltd. (Osaka, Japan), and a voucher specimen
MAP-MY1008 is deposited at the Medicinal Plant Garden of the
College of Pharmaceutical Sciences, Matsuyama University. 2,2′-
Azobis(2-amidinopropane) dihydrochloride (AAPH), L-cysteine meth-
1
800
dx.doi.org/10.1021/np300212c | J. Nat. Prod. 2012, 75, 1798−1802

Journal of Natural Products
Note
−
yl ester hydrochloride, and o-tolyl isothiocyanate were purchased from
Wako Pure Chemical Industry (Osaka, Japan). Fluorescein sodium salt
and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox)
were purchased from Sigma-Aldrich (St. Louis, MO, USA).
26.2 (C-8), 24.1 (C-9); HRESIMS m/z 437.1267 [M − H] (calcd for
C H O S−H, 437.1276).
21
26
8
Juglanin B 11-sulfate (2): off-white, amorphous powder; [α]D
+23.2 (c 0.5, MeOH); IR (KBr) ν 3453, 1496, 1414, 1242, 1064,
1045, 929, 494, 420 cm ; H NMR (500 MHz, methanol-d ) δ 7.22
(1H, d, J = 2.0 Hz, H-18), 6.96 (1H, dd, J = 2.0, 8.5 Hz, H-15), 6.92
max
−1 1
Isolation Procedure. The dried and pulverized bark of M. rubra
4
(
450 g) was macerated with aqueous EtOH (4:1, v/v) (4.5 L) for 24 h,
and the filtered extract was concentrated in vacuo to 500 mL at a
temperature below 40 °C to give a yellowish precipitate (66.7 g). The
supernatant was extracted successively with n-hexane (2.5 L), EtOAc
(
1H, br s, H-19), 6.71 (1H, d, J = 8.5 Hz, H-16), 6.66 (1H, d, J = 2.0
Hz, H-5), 4.84 (1H, t, J = 9.5 Hz, H-11), 3.83 (3H, s, OMe), 3.05 (1H,
m, H-13), 2.93 (1H, m, H-7), 2.75 (1H, m, H-13), 2.48 (1H, m, H-7),
2
1.93 (4H, m, H-8, 9, 10, 12), 1.50 (1H, m, H-9); C NMR (126 MHz,
methanol-d ) δ 154.7 (C-17), 150.2 (C-4), 144.4 (C-3), 134.0 (C-18),
1
1
3
(
2.5 L), and n-BuOH (2.5 L) to give n-hexane (1.7 g), EtOAc (9.9 g),
.27 (1H, m, H-8), 2.21 (1H, m, H-12), 2.13 (1H, m, H-10), 1.78−
n-BuOH (15.6 g), and H O (20.1 g) extracts. A part (3.0 g) of the
13
2
precipitate was separated using MEGA BOND ELUT C18 (Varian)
eluted with aqueous MeOH (30% → 50% → 70%) to MeOH. The
4
31.3 (C-14), 130.5 (C-6), 130.0 (C-15), 128.4 (C-2), 128.1 (C-1),
26.5 (C-19), 117.9 (C-16), 112.4 (C-5), 79.2 (C-11), 56.8 (OMe),
30% MeOH eluant gave myricitrin (4) (2.25 g). The 70% MeOH
fraction (129.9 mg) was further separated by preparative TLC (silica
gel F254, Merck) to yield myricanol (5) (100.1 mg) and myricanone
7.8 (C-10), 34.9 (C-12), 31.7 (C-7), 27.8 (C-13), 27.3 (C-8), 24.3
−
(
4
C-9); HRESIMS m/z 407.1181 [M − H] (calcd for C H O S−H,
2
0
24
7
(6) (5.8 mg).
07.1170).
Myricanone 5-O-(6′-O-galloyl)glucoside (3): pale yellow, amor-
The EtOAc extract (9.0 g) was fractionated by column
chromatography on a Toyopearl HW-40C column (40 × 2.2 cm
i.d.) with aqueous MeOH (20% → 30% → 40% → 50% → 60% →
1
phous powder; H NMR (500 MHz, methanol-d ) δ 7.01 (1H, dd, J =
2
1
=
4
.5, 8.0 Hz, H-15), 6.99 (2H, s, galloyl-H), 6.76 (1H, d, J = 8.0 Hz, H-
6), 6.50 (1H, d, J = 2.5 Hz, H-18), 6.49 (1H, s, H-19), 5.04 (1H, d, J
7.0 Hz, Glc H-1), 4.38 (2H, m, Glc H-6), 3.84, 3.92 (each 3H, s,
7
0% → 80%) → MeOH → H O−acetone (3:7, v/v) to fractions M1−
2
M26 (20%, M1−M7; 30%, M8−M10; 40%, M11−M14; 50%, M15−
M19; 60%, M20−M22; 70%, M23−M26) and 80% MeOH, MeOH,
OMe), 3.48−3.52 (4H, m, Glc H-2−H-5), 2.82−2.92 (4H, m, H-12,
and H O−acetone (3:7, v/v) eluates, with monitoring by RP HPLC.
2
H-7, H-13), 2.55−2.65 (3H, m, H-10, H-7, H-12), 2.26 (1H, m, H-
Gallic acid (7) (461.4 mg) was obtained from fraction M5. Fractions
M8−M10 were applied to a YMC-gel ODS AQ column (25 × 1.1 cm
i.d.) eluted with aqueous MeOH (30% → 40%) → MeOH, and the
1
3
1
0), 1.82 (1H, m, H-8), 1.66 (1H, m, H-8), 1.47 (2H, m, H-9); C
NMR (126 MHz, methanol-d ) δ 215.6 (C-11), 168.3 (galloyl-7),
1
4
52.9 (C-17), 149.9 (C-5), 149.0 (C-3), 146.7 (C-4), 146.6 (2C,
30% MeOH eluate was further chromatographed on Sephadex LH-20
galloyl-3, 5), 139.9 (galloyl-4), 134.0 (C-18), 132.5 (C-14), 130.0 (2C,
C-2, 15), 129.9 (C-19), 129.8 (C-6), 126.3 (C-1), 121.5 (galloyl-1),
117.5 (C-16), 110.1 (2C, galloyl-2, 6), 105.0 (Glc C-1), 77.8 (Glc C-
3), 75.7 (Glc C-2), 75.5 (Glc C-5), 71.7 (Glc C-4), 64.9 (Glc C-6),
62.0, 62.1 (each 1C, OMe), 44.7 (C-10), 42.3 (C-12), 28.0 (C-13),
27.9 (C-7), 25.7 (C-8), 23.4 (C-9); HRESIMS m/z 669.2163 [M −
(
25 × 1.1 cm i.d.) eluted with EtOH to afford actinidione (9) (13.7
mg) and (S)-myricanol 5-O-(6′-O-galloyl)glucoside (14) (23.5 mg).
Fraction M11 was subjected to a YMC-gel ODS AQ column (25 × 1.1
cm i.d.) eluted with aqueous MeOH (30% → 40% → 50%) → MeOH
to yield myricanone 5-O-(6′-O-galloyl)glucoside (3) (4.8 mg) and
(
5
R)-myricanol 5-O-(6′-O-galloyl)glucoside (13) (70.1 mg) from the
−
0% MeOH eluate. The 40% MeOH eluate was further purified using
H] (calcd for C H O −H, 669.2189).
34
38 14
a Sephadex LH-20 column (25 × 1.1 cm i.d.) eluted with EtOH to
yield myricetin (8) (13.1 mg). Fractions M16 and M17 were subjected
to a Sephadex LH-20 column (25 × 1.1 cm i.d.) eluted with EtOH to
afford epigallocatechin 3-O-gallate (10) (134.1 mg). Fractions M18
and M19 were chromatographed on a Chromatorex DM1020T
column (25 × 1.1 cm i.d.) eluted with aqueous MeOH (20% → 25%)
Acid Hydrolysis of Compound 3. A solution of compound 3
(0.5 mg) in 0.5 M HCl (0.3 mL) was heated at 105 °C for 1.5 h. After
neutralization with Amberlite IRA-400 (Organo Co.), the mixture was
analyzed by reversed-phase HPLC to detect an aglycone identical to
myricanone (t 44.7 min) and gallic acid (t 2.9 min).
R
R
To characterize the liberated sugar component, the supernatant was
→
MeOH, yielding myricetin 3-O-(2″-O-galloyl)rhamnoside (11)
evaporated under a N stream, and the residue was heated with L-
2
(
32.0 mg). Sephadex LH-20 column (25 × 1.1 cm i.d.)
cysteine methyl ester hydrochloride (0.5 mg) in pyridine (0.5 mL) at
chromatography of fraction M22 eluted with EtOH afforded
prodelphinidin B-2 3,3′-di-O-gallate (12) (90.5 mg).
The n-BuOH extract was fractionated by column chromatography
on a Toyopearl HW-40C column (40 × 2.2 cm i.d.) with aqueous
6
0 °C for 1 h. o-Tolyl isothiocyanate (0.5 mg/0.5 mL pyridine) was
added to the mixture, which was further reacted at 60 °C for 1 h. The
reactant was analyzed by HPLC equipped with a C18 column eluting
with 25% MeOH in 50 mM H PO . The retention time of the product
3
4
MeOH (30% → 40% → 50% → 60% → 70%) → MeOH → H O−
2
(
tR 24.2 min) was identical to that of an authentic o-tolylthiocarbamate
acetone (3:7, v/v) into fractions M27−M43 (30%, M27−M29; 40%,
M30−M32; 50%, M33,M34; 60%, M35−M39; 70%, M40−M43) →
derivative (tR 24.4 min) prepared from D-glucose under the same
conditions.
MeOH and H O−acetone (3:7, v/v) eluate. Fraction M28 (1.8 g/4.2
2
Antioxidative Assay. The antioxidative activity was estimated by
ORAC and SOD-like activity assays. ORAC values were measured
g) was separated using a Cosmosil 75C18 column (20 × 1.1 cm i.d.)
eluted with aqueous MeOH (30% → 50%) → MeOH, to afford
myricanol 11-sulfate (1) (6.5 mg) and juglanin B 11-sulfate (2) (5.3
mg).
14
according to the reported method. Briefly, a sample solution of a 75
mM phosphate buffer (pH 7.0, 20 μL) and 94.4 nM fluorescein
solution (200 μL) were pipetted into each well of a 96-well microplate
and incubated for 15 min at 37 °C. After adding a 31.7 mM AAPH
solution (75 μL) and shaking for 15 s, the fluorescence was recorded
every 2 min for 90 min at respective excitation and emission
wavelengths of 485 and 535 nm. The area under the curve (AUC) of
each sample was calculated relative to the initial value (the
fluorescence intensity at 0 min), and the blank value was subtracted.
ORAC values (μmol Trolox equivalent/g) were calculated from a
curve of Trolox concentration vs AUC value. Data are expressed as the
mean ± SD of more than two separate experiments. The SOD-like
activity was measured by using the SOD Assay kit-WST (Dojindo
Laboratories, Kumamoto, Japan) according to the methods indicated
by the manufacturer. Data are averaged values of more than two
separate experiments.
Myricanol 11-sulfate (1): off-white, amorphous powder; [α]D
28.6 (c 0.5, MeOH); IR (KBr) νmax 3390, 2940, 1506, 1496, 1457,
−
1
5
409, 1349, 1231, 1114, 1067, 1044, 966, 948, 928, 897, 809, 626, 596,
−1 1
86 cm ; H NMR (500 MHz, methanol-d ) δ 7.13 (1H, d, J = 2.0
4
Hz, H-18), 7.01 (1H, dd, J = 2.0, 8.5 Hz, H-15), 6.91 (1H, s, H-19),
6
3
2
2
1
.75 (1H, d, J = 8.5 Hz, H-16), 4.71 (1H, t, J = 9.5 Hz, H-11), 3.83,
.89 (each 3H, s, OMe), 3.03 (1H, m, H-13), 2.79 (1H, m, H-13),
.72 (1H, m, H-7), 2.53 (1H, ddd, J = 2.0, 12.5, 17.5 Hz, H-7), 2.16−
.26 (2H, m, H-8, 12), 2.10 (1H, m, H-10), 1.80−1.91 (3H, m, H-8,
13
0, 12), 1.71 (1H, m, H-9), 1.48 (1H, m, H-9); C NMR (126 MHz,
methanol-d ) δ 152.5 (C-17), 150.3 (C-5), 148.4 (C-3), 141.0 (C-4),
4
134.2 (C-18), 132.4 (C-14), 130.70, 130.73 (each 1C, C-15, 19), 126.5
(
(
C-1), 124.4 (C-2), 124.1 (C-6), 117.5 (C-16), 78.6 (C-11), 61.5, 61.6
each 1C, OMe), 37.5 (C-10), 34.4 (C-12), 27.9 (C-13), 26.8 (C-7),
1
801
dx.doi.org/10.1021/np300212c | J. Nat. Prod. 2012, 75, 1798−1802

Journal of Natural Products
Note
ASSOCIATED CONTENT
Supporting Information
■
*
S
IR and NMR spectra of myricanol 11-sulfate (1), juglanin B 11-
sulfate (2), and myricanone 5-O-(6′-O-galloyl)glucoside (3) are
included. This material is available free of charge via the
Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
Tel: +81-89-925-7111. Fax: +81-89-926-7162. E-mail:
amakura@cc.matsuyama-u.ac.jp.
■
*
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by a Health Sciences Research Grant
from the Ministry of Health, Labour and Welfare of Japan.
■
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