Available online at www.sciencedirect.com
Bioorganic & Medicinal Chemistry Letters 18 (2008) 523–526
Antiproliferative effects of dibenzocyclooctadiene lignans
isolated from Schisandra chinensis in human cancer cells
Hye-Young Min,a Eun-Jung Park,a Ji-Young Hong,a You-Jin Kang,a Sun-Jack Kim,a
Hwa-Jin Chung,a Eun-Rhan Woo,b Tran Manh Hung,c Ui Jung Youn,c Yeong Shik Kim,d
Sam Sik Kang,d KiHwan Baec and Sang Kook Leea,*
a
College of Pharmacy, Ewha Womans University, 11-1 Daehyun-dong, Seodaemun-ku, Seoul 120-750, Republic of Korea
b
College of Pharmacy, Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759, Republic of Korea
c
College of Pharmacy, Chungnam National University, 220 Kung-dong, Yuseong-ku, Daejeon 305-764, Republic of Korea
d
Natural Products Institute, College of Pharmacy, Seoul National University, 28 Yungun-dong, Jongro-ku,
Seoul 110-460, Republic of Korea
Received 12 October 2007; revised 17 November 2007; accepted 21 November 2007
Available online 28 November 2007
Abstract—Dibenzocyclooctadiene lignans isolated from Schisandra chinensis showed antiproliferative effects in various human cancer cells. The methoxy groups at C-3, C-4, C-3 0 , and C-4 0 , the hydroxyl group at C-8 0 , and the stereo-configuration of the biphenyl
ring and the angeloyl group might have influence on these activities. Additional studies indicate that one of mechanism of action of
an active compound schizantherin C in A549 human lung cancer cells was related to the inhibition of cell cycle progression in G0/G1
phase.
Ó 2007 Elsevier Ltd. All rights reserved.
Schisandra chinensis (Turcz.) Baill. (Schisandraceae) is
widely distributed in northeast Asia (Korea, China,
and Japan) and eastern parts of Russia.1 The fruit of
S. chinensis was traditionally used in the alleviation or
treatment of diseases due to deficiency of lung, heart
and kidney, imbalance of Yin and Yang, and impairment of Qi, such as chronic cough, asthma, spontaneous
sweating, palpitation, spermatorrhea, diabetes, insomnia, and forgetfulness.1,2 Phytochemical studies for the
isolation of constituents of S. chinensis have been extensively performed since 1970s. Various reports suggested
that major bioactive constituents of S. chinensis were
lignans belong to the dibenzocyclooctadiene type
(Fig. 1).3
metabolism in a CCl4-induced hepatotoxicity model.4
Gomisin B, gomisin G, and (+)-gomisin K3 suppressed
the formation of surface antigen or e antigen of human
type B hepatitis virus.5 Gomisin G and other related dibenzocyclooctadiene lignans showed anti-HIV activities.6
The structure–activity relationships on the antioxidant
and platelet-activating factor (PAF) antagonistic potential were also reported.7,8 In particular, together with the
range of non-cytotoxic concentration, gomisin A, schisandrin A and B, and schisantherin A restored cytotoxic
activities of anticancer agents in multidrug-resistant human cancer cells, and schisandrin B selectively enhanced
3
It has been reported that dibenzocyclooctadiene lignans
possess hepatoprotective, antiviral, antioxidant, cytotoxic, and cancer chemopreventive activities.1,4–10 The
aqueous extract of S. chinensis restored hepatic drug
A
0960-894X/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2007.11.082
1
5
6
6'
5'
4'
Keywords: Dibenzocyclooctadiene lignan; Schisantherin C; Antiproliferation; Cancer; Cell cycle arrest; A549.
* Corresponding author. Tel.: +82 2 3277 3023; fax: +82 2 3277
2851; e-mail: sklee@ewha.ac.kr
2
4
9
8
C
B
1'
3'
7
7'
8'
9'
2'
Figure 1. Chemical structures of C18-dibenzocyclooctadiene.
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H.-Y. Min et al. / Bioorg. Med. Chem. Lett. 18 (2008) 523–526
cytotoxic and proapoptotic effects of doxorubicin.9–11 In
addition, schisantherin G and propinquanin E were
cytotoxic in human cancer cells,12 and gomisin A inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced tumor formation in a two-stage mouse
carcinogenesis model.13 These findings imply anticancer
and cancer chemopreventive potential of dibenzocyclooctadiene lignans. However, previous studies
focused on only one or some lignans. Although schisandrin B induced caspase-3-dependent apoptosis in human
hepatoma cells,14 the mechanisms underlying antiproliferative effects of dibenzocyclooctadiene lignans in human cancer cells have not been studied well. In this
study, with the dibenzocyclooctadiene lignans isolated
from the fruits of S. chinensis, we made an attempt to
find the structural requirement for the antiproliferative
effect in a panel of several human cancer cell lines
(Fig. 2).15 The mechanism of action of an active compound was also investigated.
OCH3
OCH3
H3CO
H3CO
H3CO
H3CO
CH3
H3CO
H
CH3
H3CO
CH3
H3CO
H
CH3
H3CO
H
OH
H3CO
schizandrin
H3CO
O
O
O
O
H3CO
H3CO
CH3
H3CO
H
CH3
H3CO
CH3
H3CO
H
CH3
H3CO
H
OH
H3CO
H3CO
gomisin A
OH
Primarily, the inhibitory effects of dibenzocyclooctadiene lignans on the proliferation were evaluated in cultured various human cancer cells (MDA-MB-231,
breast cancer (ER ); T47D, breast cancer (ER+); SKHEP-1, hepatoma; SNU-638, stomach cancer; HCT15, colon cancer; K562, leukemia; A549, lung cancer).
Cells were treated with various concentrations of dibenzocyclooctadiene lignans for 72 h, and their antiproliferative effects were evaluated using MTT (K562) or
SRB (other cell lines) assay.16 Some dibenzocyclooctadiene lignans from S. chinensis showed the growth inhibitory effects against several cancer cells (Table 1).
Especially, schizandrin, schisantherin C, and gomisin
N showed the effective antiproliferative activities in most
of tested cancer cell lines with the IC50 values ranging
10–70 lM. In addition, active compounds exhibited relatively more potent inhibitory effects toward T47D
(ER+) cells compared with those of MDA-MB-231
(ER ) cells. From comparison of their structures with
activities, the structural necessity for the antiproliferative effect is suggested as follows. First, the substitution
groups of A and B rings might have influence on the
antiproliferative activity of dibenzocyclooctadiene lignans in cancer cells. The compounds with the methylenedioxy group at C-3 and C-4 (A ring) or C-3 0 and C-4 0 (B
ring) tend to show less potent activities than those with
methoxy groups at the same positions in comparison of
gomisin A and schizandrin, wuweizisu B and schisandrin A, and wuweizisu C and gomisin N, respectively.
In addition, the introduction of hydroxyl group at C8 0 seems to be influential and generally enhances the
activity exampled with gomisin A and wuweizisu B,
and schizandrin and schisandrin A, respectively. Second, the stereo-configuration of rings or side groups
might be also an important factor for determining the
antiproliferative potential. Compared with gomisin B,
schisantherin C, and gomisin C, the stereo-configuration
of the hydroxyl group at C-8 0 and the angeloyl group at
C-7 0 plays an important role in the antiproliferative effect. In case of possessing same side groups, the compound with R-biphenyl configuration (for example,
wuweizisu B) is less potent than one with S-biphenyl
configuration (gomisin N).
schisandrin A
wuweizisu B
O
O
H3CO
H3CO
H3CO
H
H3CO
CH3
H
H3CO
CH3
HO
H
H3CO
CH3
H
H3CO
CH3
H3CO
gomisin J
gomisin N
O
O
O
O
H3CO
H
H3CO
H3CO
H
H3CO
CH3
CH3
H3CO
CH3
H
O
O
H3CO
CH3
O
OH
O
gomisin B
wuweizisu C
H3C
CH3
O
O
O
O
H3CO
H3CO
H
H3CO
CH3
CH3
H3CO
O
H
H3CO
CH3
OH
H3CO
OH
O
O
CH3
O
H3CO
H3CO
H3C
gomisin C
schisantherin C
CH3
Figure 2. Chemical structures of dibenzocyclooctadiene lignans from
S. chinensis.
As shown in Table 1, among the tested compounds,
schisantherin C showed the most potent inhibitory effect
in all of tested human cancer cells. Since schisantherin C
was equally effective in A549 and HCT-15 cells, we further investigated the antiproliferative mechanism of
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H.-Y. Min et al. / Bioorg. Med. Chem. Lett. 18 (2008) 523–526
Table 1. Effects of dibenzocyclooctadiene lignans from S. chinensis on cell proliferation in human cancer cells
IC50 (lM)
Compound
Gomisin J
Gomisin N
Gomisin A
Gomisin B
Schizandrin
Wuweizisu C
Wuweizisu B
Schisantherin C
Schisandrin A
Gomisin C
Doxorubicin
MDA-MB-231
SK-HEP-1
SNU-638
T47D
HCT-15
K562
A549
>100
>100
>100
>100
61.5
>100
>100
33.5
>100
56.4
0.2
>100
>100
>100
>100
71.3
>100
>100
19.9
42.0
70.4
0.1
>100
23.1
90.5
>100
21.1
>100
>100
15.3
53.1
44.7
0.07
>100
19.2
>100
>100
19.8
>100
>100
26.1
40.0
51.2
0.1
>100
14.1
>100
>100
50.2
>100
88.1
5.6
>100
>100
0.6
>100
22.0
>100
>100
25.0
>100
62.6
11.3
>100
>100
NT
>100
21.1
84.1
>100
20.7
>100
87.8
5.6
>100
>100
0.1
Results are represented as IC50 values (lM). Doxorubicin was used as a positive control. (NT, not tested).
schisantherin C as one representative
enzocyclooctadiene lignans in A549 cells.
of
dib-
Inhibition of cell cycle progression and/or induction of
apoptosis have been regarded as promising strategies
for the control of the proliferation of cancer cells.17,18
Therefore, we examined the antiproliferative mechanism
of schisantherin C in relation to the regulation of cell cycle progression. A549 cells were treated with various
concentrations of schisantherin C (3.75–60 lM) for
24 h, and changes of cell cycle distribution were analyzed by flow cytometry.16 As depicted in Figure 3, schisantherin C markedly arrested cell cycle progression in a
concentration-dependent manner. At 60 lM, more than
70% of total cell population was accumulated in G0/G1
phase, and the cell population in S phase was also gradually decreased. However, the distribution of cells in
sub-G1 phase, an indication of cell death, was not increased even at the highest concentration of schisantherin C. Therefore, although the proapoptotic effect of a
dibenzocyclooctadiene lignan was reported previously,14
the mechanism underlying inhibition of cell proliferation
by schisantherin C appears to be the arrest of cell cycle
progression without cell death in A549 cells.
According to the pronounced inhibitory activity of schisantherin C, the effect of schisantherin C on the expression of proteins related to cell cycle progression was also
examined.19 Treatment of cells with schisantherin C did
not affect the expression of cyclin D1, cdk2, and cdk4
(Fig. 4). However, the expression of cyclin E and cyclin
A, proteins required for cell cycle transition from G0/G1
phase to S phase and cell cycle progression in S phase,
respectively, was decreased by treatment with 60 lM
schisantherin C. In particular, schisantherin C induced
p27 expression and inhibited phosphorylation of the retinoblastoma protein (pRB) in a dose-dependent manner.
It is known that p27 suppresses the kinase activity of cyclin E-cdk2 complex, resulting in blocking phosphorylation of pRB and inhibiting cell cycle progression toward
S phase.20 Thus, the down-regulation of cyclin E and
up-regulation of p27 lead to the suppression of pRB
phosphorylation, and, eventually, contribute to cell cy-
Schisantherin C 5 µM
Control
Cell cycle
distribution (%)
G0/G1:
S:
G2/M:
subG1:
50.3
34.4
15.4
2.0
Schisantherin C 10 µM
G0/G1:
S:
G2/M:
subG1:
50.4
31.6
18.0
1.5
Schisantherin C 40 µM
G0/G1:
S:
G2/M:
subG1:
65.3
18.8
15.9
1.1
G0/G1:
S:
G2/M:
subG1:
50.1
31.8
18.1
0.6
Schisantherin C 20 µM
G0/G1:
Cell cycle S:
distribution (%) G2/M:
subG1:
57.9
26.0
16.2
0.6
Schisantherin C 60 µM
G0/G1:
S:
G2/M:
subG1:
75.0
8.2
10.8
2.5
Figure 3. Inhibition of cell cycle progression in the G0/G1 phase of the
cell cycle by schisantherin C in A549 cells. A549 cells were treated with
various concentrations of schisantherin C for 24 h. Changes of the
distribution of cell cycle were analyzed by flow cytometry, and the
percentage of distribution in each phase of the cell cycle was
determined using ModFIT LT v.2.0 software.
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H.-Y. Min et al. / Bioorg. Med. Chem. Lett. 18 (2008) 523–526
References and notes
Schisantherin C (µM)
Control
3.75
7.5
15
30
60
cyclin D1
cyclin A
cyclin E
cdk4
cdk2
p27
phospho-Rb (S807/811)
phospho-Rb (S780)
Rb
β-actin
Figure 4. Effects of schisantherin C on the expression of proteins
related to cell cycle progression in A549 human lung cancer cells. Cells
were exposed to various concentrations of schisantherin C for 24 h.
The expression level was evaluated by Western blot analysis.
cle arrest in G0/G1 phase by schisantherin C in A549
cells.
In summary, the present study demonstrates that dibenzocyclooctadiene lignans isolated from the fruit of
S. chinensis inhibited cell proliferation in human cancer
cells, and the antiproliferative mechanism of an active
compound schisantherin C appears to be the induction
of cell cycle arrest in G0/G1 phase through down-regulation of cyclin E and up-regulation of p27 in A549 human lung cancer cells. These results present the
additional biological activity and mechanism of dibenzocyclooctadiene lignans, and also contribute to the
development of anticancer agents derived from natural
products.
Acknowledgments
This work was supported by a grant on Studies on the
Identification of the Efficacy of Biologically Active
Components from Oriental Herbal Medicines from the
Korea Food and Drug Administration (2005).
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