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.