Monoterpenoids from the aerial parts of Aruncus dioicus var. kamtschaticus and their antioxidant and cytotoxic activities

Article abstract of DOI:10.1016/j.bmcl.2011.04.043

The aerial parts of Aruncus dioicus var. kamtschaticus afforded five new monoterpenoids (1-5): 4-(erythro-6,7-dihydroxy-9-methylpent-8-enyl)furan-2(5H)- one (1, aruncin A), 2-(8-ethoxy-8-methylpropylidene)-5-hydroxy-3,6-dihydro-2H- pyran-4-carboxylic acid (2, aruncin B), 4-(hydroxymethyl)-6-(8-methylprop-7- enyl)-5,6-dihydro-2H-pyran-2-one-11-O-β-d-glucopyranoside (3, aruncide A), (3S,4S,5R,10R)-3-(10-ethoxy-11-hydroxyethyl)-4-(5-hydroxy-7-methylbut-6-enyl) oxetan-2-one-11-O-β-d-glucopyranoside (4, aruncide B), and (3S,4S,5R,7R)-5-(9-methylprop-8-enyl)-1,6-dioxabicyclo[3,2,0] heptan-2-one-7-(hydroxymethyl)-12-O-β-d-glucopyranoside (5, aruncide C). Compound 2 showed potent cytotoxicity against Jurkat T cells with an IC ₅₀ value of 17.15 μg/mL. In addition, compounds 7 and 10 exhibited moderate antioxidant activity with IC₅₀ values of 46.3 and 11.7 μM, respectively.

Full text of DOI:10.1016/j.bmcl.2011.04.043

Bioorganic & Medicinal Chemistry Letters 21 (2011) 3252–3256
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Monoterpenoids from the aerial parts of Aruncus dioicus var. kamtschaticus
and their antioxidant and cytotoxic activities
Su Yang Jeong a, Do Youn Jun b, Young Ho Kim b, Byung-Sun Min a, Bo Kyung Min a, Mi Hee Woo a,
⇑
a College of Pharmacy, Catholic University of Daegu, Gyeongsan 712-702, Republic of Korea
b Laboratory of Immunobiology, School of Life Science and Biotechnology, College of Natural Sciences, Kyungbuk National University, Daegu 702-701, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
The aerial parts of Aruncus dioicus var. kamtschaticus afforded five new monoterpenoids (1–5):
4-(erythro-6,7-dihydroxy-9-methylpent-8-enyl)furan-2(5H)-one (1, aruncin A), 2-(8-ethoxy-8-methylpro-
pylidene)-5-hydroxy-3,6-dihydro-2H-pyran-4-carboxylic acid (2, aruncin B), 4-(hydroxymethyl)-6-(8-
Received 1 February 2011
Revised 21 March 2011
Accepted 11 April 2011
Available online 17 April 2011
methylprop-7-enyl)-5,6-dihydro-2H-pyran-2-one-11-O-b-
R)-3-(10-ethoxy-11-hydroxyethyl)-4-(5-hydroxy-7-methylbut-6-enyl)oxetan-2-one-11-O-b-
oside (4, aruncide B), and (3S,4S,5R,7R)-5-(9-methylprop-8-enyl)-1,6-dioxabicyclo[3,2,0]heptan-2-one-7-
(hydroxymethyl)-12-O-b- -glucopyranoside (5, aruncide C). Compound 2 showed potent cytotoxicity
against Jurkat T cells with an IC50 value of 17.15 g/mL. In addition, compounds 7 and 10 exhibited moderate
antioxidant activity with IC50 values of 46.3 and 11.7 M, respectively.
D-glucopyranoside (3, aruncide A), (3S,4S,5R,10
D-glucopyran
Keywords:
D
Aruncins A and B
Aruncides A–C
Aruncus dioicus
Rosaceae
l
l
Crown Copyright Ó 2011 Published by Elsevier Ltd. All rights reserved.
Cytotoxicity
Ulleungdo is located 130 km from the mainland of Korea and
has special local products including edible wild vegetables and
marine products.1 Aruncus dioicus var. kamtschaticus (Rosaceae) is
the major wild leafy vegetable produced in Ulleungdo.2 Biological
studies have revealed that this plant possesses numerous effects
such as antioxidant,3,4 antidiabetic,5 and anti-AIDS6 effects and
can be used in the prevention and treatment of ischemic and
degenerative brain diseases.7 The dried sprouts of this plant have
been used for foods and the aerial parts to treat detoxification
and tonsillitis.8 However, their chemical constituents have not
been reported.
This study was conducted to identify the bio-active compounds
in this plant. The aerial parts of A. dioicus9 were extracted with 95%
EtOH, concentrated and fractionated into n-hexane, CH2Cl2, EtOAc,
n-BuOH and H2O fractions. The EtOH extract and fractions were
examined for their DPPH radical scavenging activity.10,11 Among
the samples tested, the CH2Cl2 and EtOAc fractions showed radical
scavenging activity.
Compounds 6–12 were identified as: prunasin (6),13 1-feruloyl-b-
D
-glucose (7),14 1-p-coumaroyl-b-
3-O-b-
-glucoside (9),16 quercetin-3-O-b-
kaempferol 3-O-b-
D
-glucose (8),15 kaempferol
D
D
-glucopyranoside (10),17
D
-(6-E-p-coumarylglucoside) (11),18 and 2-
hydroxy-3-phenylpropanoic acid (12),19 by direct comparison with
authentic samples or by comparing their physical data with that in
the literature.
Compound 1 was isolated as a colorless syrup. The FABMS values
of 1 gave a [M+Na]+ peak at m/z 221. The HRFABMS gave m/z
221.0793 for the [M+Na]+, which corresponded to the molecular
formula of
1743 cmꢀ1) data suggested the presence of a hydroxy group and
an ,b-unsaturated
-lactone function. The 1H NMR spectrum indi-
cated an ,b-unsaturated -lactone moiety with two signals at dH
C10H14O4Na (calcd 221.0790). Its IR (mmax 3433,
a
c
a
c
7.45 (1H, d, J = 1.2 Hz, H-3) and 4.87 (2H, d, J = 1.2 Hz, H2-5), and
there were corresponding 13C NMR signals at dC 149.4 (C-3),
133.7 (C-4), 71.4 (C-5), and 174.2 (C-2). A combination of the 1H,
13C NMR, HMBC and COSY (Fig. 2) spectra suggested that the substi-
tuent at C-4 was a 1,2-dihydroxy-4-methyl-3-pentenyl side-chain
[{dH 4.54 (1H, d, J = 4.4 Hz, H-6), dC 70.1 (C-6)}, {dH 4.60 (1H, dd,
J = 9.0, 4.4 Hz, H-7), dC 69.6 (C-7)}, {dH 5.21 (1H, d, J = 9.0 Hz, H-8),
dC 122.8 (C-8), dC 136.4 (C-9)}, {dH 1.70, 1.74 (3H each, s, H3-10,
11), dC 17.4, 24.9 (C-10, 11)}]. The presence of two OH groups in 1
was suggested by the formation of a diacetate (1a) of 1, which gave
the expected molecular ion M+ at m/z 282 in the EIMS and exhibited
twos singlets at d 2.08 and d 2.04 in the 1H NMR spectrum of 1a. The
absolute configuration at C-6 and C-7 in 1 could not be determined
by Mosher’s ester methodology20–22 because of the decomposition
Activity-directed isolation of the CH2Cl2 and EtOAc fractions re-
sulted in the identification of five new monoterpenoids (1–5)
(Fig. 1) and seven known compounds (6–12) by RP-C18 and silica
gel column chromatographies.12 In this Letter, we report the isola-
tion and structural elucidation of these compounds, their cytotoxic
activity against Jurkat T cells, and their DPPH radical scavenging
activity.
⇑
Corresponding author. Tel.: +82 53 850 3620; fax: +82 53 850 3602.
E-mail address: woomh@cu.ac.kr (M.H. Woo).
0960-894X/$ - see front matter Crown Copyright Ó 2011 Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.04.043

S. Y. Jeong et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3252–3256
3253
FABMS. The HRFABMS spectral analysis of 2 showed the [M+Na]+
at m/z 265.1056, which corresponded to the molecular formula of
O
12
11
9
10
8
2
3
6
C12H18O5Na (calcd 265.1052). The IR spectrum of 2 indicated
1
O
O
O
O
7
5
1
8
absorption bands due to hydroxy and ,b, ,d-conjugated carbox-
a c
2
6
5
7
9
OR
erythro
4
ylic acid functions at 3405 and 1724 cmꢀ1, respectively. The 1H
and 13C NMR spectra of 2 showed signals of 5,6-dihydro-2H-pyran
with carboxyl and hydroxy groups at dH 7.47 (1H, s, H-3), 4.29 (1H,
dd, J = 5.6, 4.4 Hz, H-5), 3.76 (1H, dd, J = 12.0, 4.4 Hz, H-6a), and
3.65 (1H, dd, J = 12.0, 5.6 Hz, H-6b). The corresponding carbon res-
onances of these protons were observed at dC 147.4 (C-2), 143.1
(C-3), 132.1 (C-4), 76.7 (C-5), 64.2 (C-6), and 170.8 (C-13) in the
HSQC and HMBC spectra. A combination of the 1H, 13C NMR, HMBC
and COSY (Fig. 2) spectra suggested that the substituent at C-2 was
a 2-ethoxy-2-methyl-3-propenyl side-chain [{dH 5.57 (1H, s, H-7),
dC 125.0 (C-7)}, {dH 1.50 (6H, s, H3-9,10), dC 30.3 (C-9,10)}, {dH
3.57 (2H, q, J = 7.2 Hz, H2-11), dC 66.7 (C-11)}, {dH 1.22 (3H, t, H3-
12), dC 15.8 (C-12)}]. The absolute stereochemistry of C-5 in 2
couldn’t be determined by Mosher’s ester methodology20–22 be-
cause of the decomposition of 2 during the reaction. Therefore,
compound 2 was established as 2-(8-ethoxy-8-methylpropylid-
3
3
O
13 OH
2
11
10
4
4
1
O
7
8
RO
HO
O
6
O
5
OH
OH
9
10
11
OH
OH
R
H
Ac
2
3
1
1a
11
9
9
10
8
7
H
6
H
H
8
5
H
5
O
R
R
4
3
S
S
1
R
O
6
O
OR1
S
S
4
3
2
1
2
13
7
O
R
10
O
12
O
H
12
H
H
H 11
ene)-5-hydroxy-3,6-dihydro-2H-pyran-4-carboxylic
acid
and
O
OR2
HO
O
named aruncin B.
OH
Compound 3 was obtained as a colorless syrup. The molecular
weight of 3 was suggested by a [M+Na]+ peak at m/z 367 in the FAB-
MS. The HRFABMS gave a molecular ion peak at m/z 367.1369,
consistent with a molecular composition of C16H24O8Na (calcd
367.1374). The IR spectrum of 3 indicated absorption bands due to
OH
OH
R2
Glu
H
H
H
R1
H
H
S-MTPA
R-MTPA
4
5
4a
4s
4r
hydroxy and
a
,b-unsaturated lactone at 3401 cmꢀ1 and 1744 cm
,b-unsaturated
ꢀ1, respectively. The 1H NMR spectrum indicated an
a
Figure 1. Structures of compounds 1–5 isolated from the CH2Cl2 and EtOAc
fractions of A. dioicus var. kamtschaticus.
d-lactone moiety with four protons at dH 6.40 (1H, dd, J = 2.8, 2.0 Hz
H-4), 3.11 (1H, ddd, J = 16.0, 7.2, 2.0 Hz, H-5a), dH 2.63 (1H, ddd,
J = 16.0, 6.0, 2.8 Hz, H-5b), and 5.28 (1H, ddd, J = 8.8, 7.2, 6.0 Hz, H-
6), and there were corresponding 13C NMR signals at dC 127.9 (C-
3), 140.4 (C-4), 36.7 (C-5), 76.9 (C-6), and 171.9 (C-2). A combination
of the 1H, 13C NMR, HMBC and COSY (Fig. 2) spectra of 3 suggested
that the substituent at C-6 was an isobutenyl side-chain [{dH 5.25
(1H, d, J = 8.8 Hz, H-7), dC 124.6 (C-7), dC 141.1 (C-8)}, {dH 1.75 (3H,
s, H3-9), dC 18.5 (C-9)}, {dH 1.77 (3H, s, H3-10), dC 26.0 (C-10)}]. Based
on the 1H, 13C NMR and HMBC correlations (Fig. 2), a glycoside of
hydroxymethyl {dH 4.82 (1H, dd, J = 12.0, 2.0 Hz, H-11a), dH 4.89
(1H, dd, J = 12.0, 2.8 Hz, H-11b), dC 67.0 (C-11)} was attached at
C-3 (d 127.9). The signals {dH 4.30 (1H, d, J = 8.0 Hz, H-anomeric),
of 1 during the reaction. In order to deduce the absolute configura-
tion of an acyclic 1,2-diol moiety in 1, a CD method employing
dimolybdenum tetraacetate [Mo2(AcO)4] developed by Snatzke23
and Frelek24 was applied to 1 to obtain its CD spectrum in the region
of 550–250 nm. According to the rule proposed by Snatzke, the sign
of the CD band around 305 nm, which has been assigned to a metal-
to-ligand charge-transfer transition,23 correlates with the absolute
configuration of the acyclic 1,2-diol moiety in the ligating struc-
ture.24 The rule states that a complex of a ‘R’ or ‘R,R’ 1,2-diol with
dimolybdenum tetraacetate always gives rise to a negative CD band
around 305 nm, whereas a complex having a ‘S’ or ‘S,S’ 1,2-diol al-
ways gives rise to a positive CD band around 305 nm. The CD spec-
trum of 1 did not show appreciable cotton effects in the range
investigated, apart from occasional tails below 200–500 nm, which
did not interfere significantly in the CD spectrum.25 Therefore, the
relative of C-6/C-7 in 1 was determined as erythro. Thus, compound
1 was confirmed to be 4-(erythro-6,7-dihydroxy-9-methylpent-8-
enyl)furan-2(5H)-one and named aruncin A.
dC 104.4, 75.1, 77.9, 71.6, 78.1, 62.7} were identified as b-D
-glucose,26
which was further supported by GC analysis for sugar moiety ob-
tained from the acid hydrolysis of 3.27,28 Thus, compound 3 was
established as 4-(hydroxymethyl)-6-(8-methylprop-7-enyl)-5,6-
dihydro-2H-pyran-2-one-11-O-b-D-glucopyranoside and named
aruncide A.
Compound 4 was obtained as a colorless syrup. The molecular
weight of 4 was suggested by a [M+Na]+ peak at m/z 429 in the
FABMS. The HRFABMS spectral analysis of 4 showed the [M+Na]+
Compound 2 was isolated as a colorless syrup. The molecular
weight of 2 was suggested by a [M+Na]+ peak at m/z 265 in the
O
5
8
11
O1
OH
7
O
O
O
O1
1
O
1
6
3
8
7
5 O
O
12
3
4
10
7
OH
O
O
O
HO
11
4
12
11
1
O
4
13
HO
OH
OH
O
7
HO
O
O
HO
O
O
O
OH
OH
OH
OH
1'
1'
1'
OH
OH
OH
OH
OH
5
2
3
1
4
Figure 2. HMBC (single headed arrow) and COSY (bold) correlations of 1–5.

3254
S. Y. Jeong et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3252–3256
at m/z 429.1734, which corresponded to the molecular formula of
18H30O10Na (calcd 429.1737). The IR spectrum showed absorption
C
bands due to hydroxy (3,421 cmꢀ1), four-membered lactone
(1749 cmꢀ1), and double bond (1646 cmꢀ1) groups. The 1H NMR
spectrum indicated a four-membered lactone moiety with two sig-
nals at dH 3.06 (1H, dd, J = 8.8, 2.4 Hz, H-3) and 4.84 (1H, dd, J = 8.8,
7.6 Hz, H-4), and there were corresponding 13C NMR signals at dC
178.2 (C-2), 52.0 (C-3), and 82.7 (C-4). A combination of the 1H,
13C NMR, HMBC and COSY (Fig. 2) spectra of 4 suggested that the
substituent at C-4 was a 1-hydroxyprenyl side-chain [{dH 4.28
(1H, dd, J = 9.2, 7.6 Hz, H-5), dC 73.9 (C-5)}, {dH 5.21 (1H, dq,
J = 9.2, 1.2 Hz, H-6), dC 122.5 (C-6), dC 142.6 (C-7)}, {dH 1.80 (3H,
d, J = 1.2 Hz, H3-8), dC 18.8 (C-8)}, {dH 1.81 (3H, d, J = 1.2 Hz, H3-
9), dC 26.2 (C-9)}]. Furthermore, it was shown that a glycoside of
the 2-hydroxyethyl substituent with 1-ethoxy was attached at C-
3. This ethoxyl was observed at dH 3.74 (2H, q, J = 7.2 Hz, H2-12),
1.13 (3H, t, J = 7.2 Hz, H3-13), dC 68.0 (C-12), and 16.0 (C-13).
Hydroxyethyl signals were present at {dH 3.72 (1H, dd, J = 9.6,
2.4 Hz, H-11a), 4.12 (1H, dd, J = 10.0, 9.6 Hz, H-11b), dC 70.0 (C-
11)} and {dH 4.03 (1H, ddd, J = 10.0, 2.4, 2.4 Hz, H-10), dC 76.6 (C-
10)}. Anomeric and glycosidic signals at dH 4.33 (1H, d, J = 8.0 Hz)
and dC 104.8, 75.3, 78.0, 71.7, 78.3, 62.9 were established as b-
D
-glucose,26 which was further supported by GC analysis for sugar
moiety obtained from the enzymatic hydrolysis of 4.29,30
We obtained the genin moiety (4a) through enzymatic hydroly-
sis of 4 to determine the absolute stereochemistry of the chiral
center of C-5 in 4. The (R)- and (S)-methoxytrifluoromethylphenyl-
acetic acid (MTPA) esters (Mosher esters) {4s and 4r} of 4a were
prepared.31 1H-1H COSY analysis of the Mosher ester derivatives
was then performed. The 1H NMR chemical shift data of 4r and
4s showed that the absolute configuration at C-5 was R (Fig. 3).
On the basis of the established absolute configurations of com-
pound 5 due to the similarity of spectral data of chiral centers in
4 and 5, the absolute configurations of 4 were presumed as C-3S,
C-4S, C-5R, and C-10R, respectively. From the above mentioned
+0.01
+0.11
+0.02
-0.04
O-0.02
O-MTPA
5
4
3
1
2
13
O
12
-0.04
10
-0.03
-0.05
+0.01
O
-0.11
11OH
-0.05
Figure 3.
D
d (dS ꢀ dR) values obtained from MTPA esters (4s, 4r) of 4a.
Table 1
MTT cytotoxic activity of 1–12 against Jurkat
scavenging activity
T
cells and their DPPH radical
Antioxidant activity
Compound
Cytotoxic activity
IC50 g/mL)
(
l
IC50 (lM)
1
2
3
4
5
6
7
8
9
10
11
12
>100
>100
>100
>100
>100
>100
>100
46.3
>100
>100
11.7
17.15
>100
>100
>100
>100
>100
>100
>100
>100
98.3
>100
>100
>100
55.36
b
a
Auraptene
—
a
—
16.4
L-Ascorbic acid
a
NT: Not tested.
Positive control for cytotoxicity.
b

S. Y. Jeong et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3252–3256
3255
evidence, 4 was found to be (3S,4S,5R,10R)-3-(10-ethoxy-11-
hydroxyethyl)-4-(5-hydroxy-7-methylbut-6-enyl)oxetan-2-one-
line.32,33 Compound 2 showed potent cytotoxic activity with an
IC50 value of 17.15 g/mL in Jurkat T cells. Cytotoxicity for 15
l
11-O-b-
D
-glucopyranoside and named aruncide B.
was not available because of its insolubility in DMSO (Table 1).
The radical scavenging activity of compounds 1–12 were evalu-
ated in the DPPH radical scavenging assay.11 Compounds 7 and 10
exhibited relatively strong antioxidant activity with IC50 values of
Compound 5 was obtained as a colorless syrup. The molecular
weight of 5 was suggested by a [M+Na]+ peak at m/z 383 in the
FABMS. The HRFABMS spectral analysis of 5 showed the [M+Na]+
at m/z 383.1321, which corresponded to the molecular formula
of C16H24O9Na (calcd 383.1318). The IR spectrum showed absorp-
tion bands due to hydroxy (3375 cmꢀ1), four-membered lactone
(1757 cmꢀ1), and ether (1129 cmꢀ1) groups. The 1H NMR spectrum
indicated a four-membered lactone with two signals at dH 2.72 (1H,
dd, J = 9.2, 2.4 Hz, H-3) and dH 4.83 (1H, dd, J = 9.2, 7.6 Hz, H-4), and
there were corresponding 13C NMR signals at dC 175.1 (C-2), 50.9
(C-3) and 82.5 (C-4). The 1H and 13C NMR (Tables 2 and 3), HMBC
and COSY (Fig. 2) spectra of 5 showed some signals similar to 4,
confirming the presence of a four-membered lactone with a isob-
utenyl substituent [{dH 5.30 (1H, dq, J = 9.2, 1.2 Hz, H-8), dC 122.3
(C-8), dC 142.8 (C-9)}, {dH 1.78 (3H, d, J = 1.2 Hz, H3-10), dC 18.8
(C-10)}, {dH 1.80 (3H, d, J = 1.2 Hz, H3-11), dC 26.2 (C-11)}] at C-5
and a glucoside of hydroxymethyl {dH 3.87 (H, dd, J = 10.8,
2.4 Hz, H-12a), dH 4.40 (H, dd, J = 11.6, 10.8 Hz, H-12b), dC 68.8
(C-12)} at C-7. One doublet of doublet at d 4.28 (1H, J = 9.2,
7.6 Hz, H-5), one doublet of doublet of doublet at d 3.98 (1H,
J = 11.6, 2.4, 2.4 Hz, H-7) and no ethoxyl group indicated that a tet-
rahydrofuran ring was formed. The signals {dH 4.32 (1H, d,
J = 8.0 Hz, H-anomeric), dC 104.9, 75.0, 78.2, 71.9, 78.4, 62.6} were
46.3 and 11.7
ence standard,
previously reported the antioxidant activity of quercetin-3-O-b-
-glucopyranoside (10). However, DPPH radical scavenging activity
of 1-feruloyl-b- -glucose (7) has never been reported.
l
L
M, respectively (Table 1), compared with the refer-
-ascorbic acid (IC50 of 16.4
l
M). Silva et al.34 had
D
D
Acknowledgments
This work was supported by the RIC Program of the Ministry of
Knowledge and Economy (MKE). The authors are grateful to S.H.
Kim and collaborators at the Korea Basic Science Institute (Daegu)
for measuring the mass spectra.
References and notes
1. Park, H. D. Geogr. J. Korea 1997, 31, 27.
2. Cultivation of Ulleungdo Wild Vegetables; Ulleung-Gun Agriculture Technology
Center: Ulleung-Gun, 2002. p 135.
3. Kwon, J. W.; Park, J. H.; Kwon, K. S.; Kim, D. S.; Jeong, J. B.; Lee, H. K.; Sim, Y. E.;
Kim, M. S.; Youn, J. Y.; Chung, G. Y.; Geong, H. J. Korean J. Plant Res. 2006, 19, 1.
4. Kim, Y. C.; Chung, S. K. Food Sci. Biotechnol. 2002, 11, 407.
5. Shin, J. W.; Lee, S. I.; Woo, M. H.; Kim, S. D. J. East Asian Soc. Dietary Life 2008, 18,
939.
identified as b-D
-glucose,26 which was further supported by GC
analysis for sugar moiety obtained from the acid hydrolysis of
6. Min, B. S.; Bae, K. H.; Kim, Y. H.; Shimotohno, K.; Miyashiro, H.; Hattori, M. Nat.
Prod. Sci. 1998, 4, 241.
5.28,30
The 1H and 13C NMR spectra of compounds 4 and 5 were similar
with differences observed in the side chain. Therefore, the config-
uration at C-5 of compound 5 should be presumed to be the same
as that of compound 4. In the NOESY spectrum of 5, the correlation
indicated connectivities between H-5 and H-7 and between H-3
and H-4. There were no correlations between H-4 and H-5, and be-
tween H-3 and H-7. Therefore, the absolute configurations of 5
were C-3S, C-4S, C-5R, and C-7R. Based on this evidence, 5
was established as (3S,4S,5R,7R)-5-(9-methylprop-8-enyl)-1,
6-dioxabicyclo[3,2,0]heptan-2-one-7-(hydroxymethyl)-12-O-b-
7. Lee, J. W.; Han, H. S.; Hwang, K. C.; Lim, S. H.; Lee, H. K.; Kang, P. G.; Suh, S. J.;
Kim, H. J.; Lee, I. S.; Cho, M. H. Korean Patent 2006079923, 2006.
8. Kim, S. K.; Lee, S. C.; Lee, S. P.; Choi, B. S. Korean J. Plant. Res. 1998, 11, 142.
9. The A. dioicus var. kamtschaticus were purchased in July 2006 from Ulleungdo in
KyeongBuk, Republic of Korea. These materials were confirmed taxonomically
by Professor Byung Sun Min, College of Pharmacy, Catholic University of Daegu,
Korea. A voucher specimen (CUDP 200601) has been deposited at the College of
Pharmacy, Catholic University of Daegu, Korea.
10. The DPPH radical-scavenging activity was measured using the method
described by Tagashira and Ohtake11 Briefly, 10
lL of each sample dissolved
in EtOH was prepared in the 96-well microplate, and then 200 L of 100 lM
l
methanolic DPPH solution was added. After mixing and standing at room
temperature for 10 min, the absorbance of the reaction mixture was measured
at 517 nm. L-Ascorbic acid (Sigma-Aldrich; purity: >99%) was used as the
D
-glucopyranoside and named aruncide C.
positive control for DPPH radical-scavenging activity.
Twelve compounds isolated from A. dioicus var. kamtschaticus
were tested for their cytotoxic activity against the Jurkat T cell
11. Tagashira, M.; Ohtake, Y. Planta Med. 1998, 64, 555.
12. The aerial part of A. dioicus var. kamtschaticus (6.90 kg) was extracted with 95%
EtOH (180 L ꢁ 2) at room temperature for 36 h. The EtOH extract was
concentrated under reduced pressure to make an EtOH extract (2.03 kg). The
concentrated EtOH extract was suspended in H2O (6.0 L) and partitioned
successively with n-hexane (6 ꢁ 5 L, 308.0 g), CH2Cl2 (6 ꢁ 5 L, 41.7 g), EtOAc
(6 ꢁ 5 L, 121.3 g), n-BuOH (6 ꢁ 5 L, 353.8 g) and H2O (600.0 g), respectively.
The EtOH extract, n-hexane, CH2Cl2, EtOAc, n-BuOH, and H2O-soluble fractions
were assayed for DPPH radical scavenging activity. The active DPPH radical
scavenging CH2Cl2 fraction (31.5 g) was subjected to open flash column
chromatography over silica gel (6.5 ꢁ 25 cm) eluted with n-hexane–CH2Cl2
(100:0 to 0:100) and CH2Cl2–MeOH–H2O (100:0:0.1 to 0:100:0.1) gradient.
Fractions (M1 to M26) were collected and pooled according to their similar TLC
patterns. Fraction M14 (0.1167 g) was chromatographed on a reverse-phase
column (3.5 ꢁ 15 cm) using a MeOH–H2O mixture as a solvent and eluted with
a stepwise gradient (5% MeOH to 50% MeOH) to yield compounds 1 (20.6 mg)
and 2 (29.2 mg). Fraction M17 (0.2 g) was chromatographed on a reverse-
phase column (3.5 ꢁ 15 cm) using a MeOH–H2O mixture as a solvent and
eluted with a stepwise gradient (5% MeOH to 90% MeOH) to yield compounds 3
(20.2 mg) and 6 (21.1 mg). The most active DPPH radical scavenging EtOAc
fraction (121.3 g) was chromatographed over a silica gel column (15 ꢁ 35 cm)
and eluted with a gradient of CH2Cl2–MeOH–H2O to afford 55 fractions (E1–
Table 3
13C NMR (100 MHz) data for 1 in CDCl3 and 2–5 in CD3OD
a
No.
dC
1
2
3
4
5
2
3
4
5
6
7
8
9
10
11
12
13
174.2
149.4
133.7
71.4
70.1
69.6
122.8
136.4
17.4
147.4
143.1
132.1
76.7
64.2
125.0
71.2
30.3
30.3
66.7
15.8
171.9
127.9
140.4
36.7
178.2
52.0
82.7
73.9
122.5
142.6
18.8
26.2
76.6
70.0
68.0
16.0
175.1
50.9
82.5
73.3
76.9
124.6
141.1
18.5
26.0
67.0
75.2
122.3
142.8
18.8
26.2
68.8
24.9
E55). Fraction E2 (14.0 g) was chromatographed on
a silica gel column
170.8
(3.5 ꢁ 57 cm) and eluted with a gradient of CH2Cl2/MeOH/H2O (55:1:0.1 to
10:1:0.1) to afford 23 subfractions (E2.1–E2.23). Subfraction E2.7 (200.0 mg)
was chromatographed on a reverse-phase column (2.3 ꢁ 53 cm) using MeOH–
H2O mixture as a solvent and eluted with a stepwise gradient (100% H2O to
100% MeOH) to yield compound 12 (10.0 mg). Subfraction E2.13 (2.0 g) was
chromatographed on a reverse-phase column (3.5 ꢁ 57 cm) using MeOH–H2O
mixture as a solvent and eluted with a stepwise gradient (100% H2O to 100%
b-
10
20
30
40
50
60
D-Glu
104.4
75.1
77.9
71.6
78.2
62.7
104.8
75.3
78.0
71.7
78.3
62.9
104.9
75.0
78.2
71.9
78.4
62.6
MeOH) to yield compound
chromatographed on
reverse-phase column (3.5 ꢁ 57 cm) using MeOH–
H2O mixture as solvent and eluted with a stepwise gradient (100% H2O to 100%
4
(10.0 mg). Fraction E4 (3.5 g) was
a
a
Data are d (ppm) and multiplicity.

3256
S. Y. Jeong et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3252–3256
MeOH) to yield compound 5 (34.0 mg). Fraction E6 (8.0 g) was chromatogra-
was analyzed by GC experiment [column: DB-Wax column (30 m ꢁ 0.25 mm),
injection temperature: 200 °C, column temperature: 100–200 °C, rate: 4 °C/
min, and retention time: D-glucose (14.31 min)]. Peaks of hydrolysates were
phed on a reverse-phase column (3.5 ꢁ 57 cm) using MeOH–H2O mixture as a
solvent and eluted with a stepwise gradient (100% H2O to 80% MeOH) to yield
compounds
7
(40.0 mg),
8
(14.1 mg),
9
(280.0 mg), and 11 (8.2 mg),
detected by comparison to the retention time of an authentic sample (D-
respectively. Fraction E9 (3.1 g) was chromatographed on a reverse-phase
column (3.5 ꢁ 57 cm) using MeOH–H2O mixture as a solvent and eluted with a
stepwise gradient (100% H2O to 80% MeOH) to yield compound 10 (48.0 mg).
13. Cardona, L.; Fernandez, I.; Prdro, J. R.; Vidal, R. Phytochemistry 1992, 31, 3507.
14. Moriguchi, T.; Villegas, R. J. A.; Kojima, M. Plant Cell Physiol. 1988, 29, 1221.
15. Dubeler, A.; Voltmer, G.; Gora, V.; Lunderstadt, J.; Zeeck, A. Phytochemistry
1997, 45, 51.
16. Wu, H.; Dushenkov, S.; Wu, S.; Ho, C. T.; Sang, S. M. Food Chem. 2009, 115, 592.
17. Kim, K. H.; Kim, M. N. Yakhak Hoeji 1992, 36, 556.
18. Kaouadji, M. Phytochemistry 1997, 29, 2295.
19. Evidente, A.; Iacobellis, N. S.; Scopa, A.; Surico, G. Phytochemistry 1990, 29,
1491.
20. Dale, J. A.; Mosher, H. S. J. Am. Chem. Soc. 1973, 95, 512.
21. Gu, Z. M.; Fang, X. P.; Zeng, L.; Kozlowski, J. F.; McLaughlin, J. L. J. Org. Chem.
1994, 59, 5162.
22. Rieser, M. J.; Hui, Y. H.; Rupprecht, J. K.; Kozlowski, J. F.; Wood, K. V.;
McLaughlin, J. L.; Hanson, P. R.; Zhuang, Z. P.; Hoye, T. R. J. Am. Chem. Soc. 1992,
114, 10203.
23. Snatzke, G.; Wagner, U.; Wolff, H. P. Tetrahedron 1981, 37, 349.
24. Frelek, J.; Ikekawa, N.; Takatsuto, S.; Snatzke, G. Chirality 1997, 9, 578.
25. Lorenzo, D. B.; Gennaro, P.; Carmela, P.; Dario, P.; Piero, S. J. Org. Chem. 2001, 66,
4819.
26. Bok, J. W.; Lermer, L.; Chilton, J.; Klingeman, H. G.; Neil Towers, G. H.
Phytochemistry 1999, 51, 891.
27. Zhao, J.; Nakamura, N.; Hattori, M.; Kuboyama, T.; Tohda, C.; Komatsu, K. Chem.
Pharm. Bull. 2002, 50, 760.
28. Compounds 3 and 5 (1 mg) were each refluxed with 2 mL of 1 N HCl (1,4-
dioxane–H2O, v/v, 1:1) at 80 °C for 3 h, respectively. Each mixture was
extracted with CH2Cl2 to afford the aglycone, and the aqueous layer was
neutralized with Na2CO3 and filtered. To the evaporate filtrates were added
1-(trimethylsilyl)imidazole (0.2 mL) and pyridine (0.2 mL), with the whole
stirred at 60 °C for 5 min. After the reaction mixture was dried under a stream
of N2, each residue was partitioned between CHCl3 and H2O. Each CHCl3 layer
glucose for 3 and 5) treated with 1-(trimethylsilyl)imidazole.
29. Min, B. S.; Thu, C. V.; Dat, N. T.; Dang, N. H.; Jang, H. S.; Hung, T. M. Chem.
Pharm. Bull. 2008, 56, 1725.
30. Naringinase (100 mg, from Penicillium decumbens) was added to a suspension
of 4 (3 mg) in 50 mm acetate buffer (pH 5.5), and the mixture was stirred at
37 °C for 5 h. The reaction mixture was extracted with EtOAc (10 mL ꢁ 3), and
the organic layer was evaporated to dryness to obtain 4a (1.5 mg). The H2O
layer was checked by silica gel TLC (EtOAc/MeOH/H2O/AcOH, 65:20:15:15).
The spot on the TLC plate was visualized with an anisaldehyde-H2SO4 reagent.
The configuration of glucose was determined by a GC method, and the sugar
derivative thus obtained showed a retention time of 14.31 min, identical to
that of authentic
31. To 0.5 mg of 4a in 0.5 mL of CH2Cl2 were added sequentially 0.2 mL pyridine,
-methoxy-a-
D-glucose.
0.5 mg 4-(dimethylamino)-pyridine, and 12 mg of (R)-(ꢀ)-
a
(trifluoromethyl)-phenylacetyl (R-MTPA) chloride, separately. The mixture
was left at room temperature overnight and purified over a micro-column
(0.6 ꢁ 6 cm) of Si gel (230–400 mesh) eluted with 3–4 mL of n-hexane/CH2Cl2
(1:2); the eluate was dried, CH2Cl2 (5 mL) was added, and the CH2Cl2 was
washed using 1% NaHCO3 (5 mL ꢁ 2). The washed eluate was dried in vacuo to
give the S Mosher ester (4s) of 4a. Using (S)-MTPA chloride afforded the R
Mosher ester (4r).
32. Park, E. J.; Nan, J. X.; Kim, J. Y.; Kang, H. C.; Choi, J. H.; Lee, S. J.; Lee, B. H.; Kim, S.
J.; Lee, J. H.; Kim, Y. C.; Sohn, D. H. J. Pharm. Pharmacol. 2000, 52, 875.
33. Cytotoxicity was measured using a modified MTT assay. The Jurkat T cells
(2.5 ꢁ 104 cells/well) were seeded on 96-well microplates and were
precultured for 36 h. MTT solution (1.1 mg/mL) was added to each well and
incubated for an additional 4 h. The colored formazan crystal produced from
the MTT was dissolved in dimethyl sulfoxide (DMSO). The optical density (OD)
values of the solutions were measured at 540 nm using a plate reader. All cell
lines were purchased from the Korean Cell Line Bank (Seoul, Korea).
34. Silva, C. G.; Raulino, R. J.; Cerqueira, D. M.; Mannarino, S. C.; Pereira, M. D.;
Panek, A. D.; Silva, J. F. M.; Menezes, F. S.; Eleutherio, E. C. A. Phytomedicine
2009, 16, 761.