METHODS
Five different cycloartane-type saponins (Astragaloside IV, Cyclocanthoside E, Astrasieversianin X,
Macrophylosaponins B and D) were incubated with MCF-7 and MDA-MB-231 cells for 24, 48, and 72
h. Cell cytotoxicity activity of saponins on cell lines was determined by cell counting kit 8. For apoptosis
analysis, TUNEL Assay Kit was used.
RESULTS
Significant changes in cytotoxicity were obtained at concentrations of 10 ?M, 100 ?M and 200 ?M for 24
h, at concentrations of 100 ?M and 150 ?M for 48 h, and at concentrations of 10 ?M and 100 ?M for 72
h in the MDA-MB-231 cells, respectively. In MCF-7 cells, no significant changes in the cell cytotoxicity
were obtained between the control and administered concentrations for 24 h but significant changes
were obtained at all concentrations (10 Left BraceM, 100 Left BraceM, 150 Left BraceM, 200 Left BraceM) for 48 h and at concentration of
100 Left BraceM for 72 h. There was a significant change in the apoptosis analysis for the MCF-7 cells at concentrations
of 10 Left BraceM and 100 Left BraceM for 48 h.
CONCLUSION
All in all, this study suggests that low-dose saponin glycosides decreased cell viability of breast cancer
cell and increased apoptosis in MCF-7 cells.
Keywords: Astragalus species; cancer; cycloartane-type saponins; MCF-7; MDA-MB-231
The Astragalus L. species, which belongs to the Fabaceae
(legume) family, has attracted great interest in
many different societies, especially Chinese and Turkish,
since ancient times. Raw extracts and isolated components
of Astragalus species, which is known to be
represented by approximately 440 species in the flora of
Turkey, showed anti-inflammatory, antioxidative, anticancer,
and antiviral activities. Cycloartane-type saponins
and polysaccharides are the most important components
of Astragalus.[
In this study, five different (astragaloside IV, cyclocanthoside
E, astrasieversianin X, macrophylosaponins
B and D) cycloartane-type saponins isolated from Astragalus
species, whose effects on breast cancer have
not been studied, were investigated at several doses on
MCF-7 and MDA-MB-231 breast cancer cell lines and
their cytotoxic, antiproliferative, and antiapoptotic activities
were investigated.
Cell Preparation
Cell Viability/Cytotoxicity Assays
Apoptosis Detection by TUNEL Method
Statistical Analysis
MCF-7 and MDA-MB-231 (American Type Culture
Collection, Rockville, Maryland, USA) cell lines are
generally used in breast cancer cell studies. MCF-7 cells have weak invasion and migration capacity when
compared to MDA-MB-231 cells.[
To evaluate the cytotoxic activity of saponins from Astragalus
species on the proliferation of breast cancer
cells, the TEBUBIO cell counting kit 8 (CCK 8) assay
was applied in accordance with the kit procedure.
100 µL cell were placed in 96-well plates based on cell
count. After 24 h of incubation, different concentrations
of Astragalus extracts (10 µM, 100 µM, 150 µM,
200 µM) were added to cell for 24 h, 48 h, and 72 h.
Then cells, with the use of CCK-8 product, were incubated
for 4 h. The absorbances are determined at 450
nm wavelength in an absorbance microplate reader.
Apoptosis detection with the effect of saponins was
evaluated by the Apoptag Plus Peroxidase in Situ (Sigma-
Aldrich, USA) kit on the cancer cells. Cells were
proliferated on slides and different types of Astragalus
saponins, at concentrations of 10 µM and 100 µM,
were added based on the IC50 value from the cell viability
assay and stained according to the kit procedure
for 24-48 h. TUNEL-positive stained cells in groups
treated with Astragalus saponins at different times and
concentrations were counted in 10 fields with ×40 objective
magnification. This method was done over one
repetition for each Saponins.
A significant difference between groups was evaluated
by Kruskal-Wallis test using PAWS STATISTIC 18. Intra-
group significance was evaluated with the Mann-
Whitney U test. The viability/cytotoxicity results of the
cells for the different saponins concentrations at different
time intervals were evaluated using GRAPHPAD
PRISM SOFTWARE (version 8). P<0.05 values were
statistically significant.
For the MDA-MB-231 cell line after 24h, the mean
difference was not significant at 95% confidence level
(CI) between the control absorbency value and absorbency
values obtained at 200 µM and 150 µM
saponins concentrations. However, cell viability decreased
significantly at 10 µM and 100 µM concentrations
and the control group after 24 h exposure. Furthermore,
after 48 h exposure, significance was observed
at 100 µM and 150 µM concentrations and the control
group. The mean difference was significant at the 95% CI
between the control absorbency value and absorbency
values obtained at 10 µM and 100 µM concentrations
of saponins after 72h exposure. The absorbency value
at the lowest concentrations of saponins was the lowest
when compared to other concentrations. Hence, the lowest concentrations have the highest cytotoxic effect
on both MCF-7 and MAD-MB-231 breast cancer cells.
Breast cancer cell growth was significantly inhibited in
both cell lines depending on dose and time within 24-
48-72 h (p<0.05) (Figs.
MCF-7: Michigan Cancer Foundation-7; CCK8: cell
counting kit 8.
MDA-MB-231: Isolated at M D Anderson from a pleural
effusion of a patient with invasive ductal carcinoma;
CCK8: cell counting kit 8.
CCK8: cell counting kit 8.
TUNEL Analysis
When p values of the saponin species used in the MDAMB-
231 cell line were compared with the control, there
was no statistically significant. A strong activity of the
cycloartane-type glycosides on the MCF-7 cell line was
observed. 10 µM and 100 µM of glycoside samples were
added to breast cancer cells for 48 h showing an increase
in the number of cell apoptosis (Fig.
Saponins are commonly found in flowering plants
(Angiospermae) of medicinally important plants species
such as Aesculus hippocastanum L., Gycyrrhiza inflata Bat., Panax ginseng C.A.Mey., Astragalus L., Bupleurum
chinense DC., Primula vulgaris Huds., Cyclaminos
Heldr. and Hedera helix L. from the subdivision Dicotyledonae and Dioscorea, Smilax, and Ruscus from the
Monocotyledonae subdivision. They are glycosides with
a triterpenic aglycone structure in dicots or a steroidal
aglycone in monocots. They have cardioprotective, anti-
inflammatory, anti-viral, and immunoregulatory effects.
Araliaceae, Leguminosae, Polygalaceae, and Campanulaceae
families are important sources for saponins.
Saponins show an anti-cancer property with different
pathways such as proliferation, metastasis, angiogenesis,
and autophagy regulation.[
In gastrointestinal cancer, saponins regulate many
cancer signaling pathways, affect the immune system,
and interact with various transcription molecules against
inflammation.[
There are many researches on the activity of saponins
in breast cancer. It has been suggested that saponins have anticancer, cytotoxic, proapoptotic, and
anti-invasive effects. It has been proven that ginseng
saponins can create a valid therapeutic effect for breast
cancer treatment by demonstrating its anti-metastatic
effect against 4T1 cells metastatic breast cancer cell.[
A study demonstrated Astragalus species has an
anticancer effect with its immunostimulating activity
[
Astragalus polysaccharides with chemotherapy can
prevent tumor development, decrease the toxicity of
chemotherapy, increase immunity and heal the quality
of cancer patient life.[
Apatinip and Astragalus polysaccharides, which are
used in the gastric cancer therapy, inhibit the increase
of cancer cells depending on the dose and cause an increase
in apoptosis.[
In our study, possible cytotoxic and apoptotic activities
of saponins obtained from Astragalus species on
breast cancer cell lines were revealed in the light of research
investigating the anticancer properties of saponins.
This is the first study investigating the antitumor
properties of different saponin extracts from Astragalus
species in breast cancer. The result of the research, low
dose saponin extracts reduce the viability of cell lines,
more significantly in MCF-7 cells, increased apoptosis
in MCF-7 cell line. Cell viability as evaluated with the
CCK-8 test, which is one of the cytotoxicity methods,
and the anticancer effects of saponins were examined.
Significant cytotoxic effects were demonstrated in low
doses at 48 and 72 h. With these conclusions, it has been
proven that Astragalus saponins inhibit breast cancer
cells proliferation depending on a dose and time. In one
report, the antitumor activity of total saponins of Paris
forrestii on human prostate cancer cell lines (PC3) was
evaluated. Cells were treated with 0, 2, 4, 6, 8, and 10
µM saponins for 6, 24, and 48 h. As a result, 1 µM and
2 µM of saponins significantly suppressed the invasion
and migration of PC3 cells. Saponins of P. forrestii can
induce apoptosis of human prostate cancer cell lines at
very low doses.[
Apoptosis essential in the assessment of anticancer
properties of plant extracts. Apoptosis is the elimination
of unwanted and unrepaired cells. Apoptosis is
among the aims of cancer treatment methods such as
chemotherapy. The level between cell proliferation and
cell death is disrupted in cancer. Fact that natural compounds
that stimulate cell death can be used as drugs
cause an increase in studies on this subject. There
are studies showing the cytotoxic effects of saponins
through apoptosis to prevent cancer formation.[
These results showed that saponins obtained from
Astragalus have important antiproliferative and antiapoptotic
effects in the MCF-7 cell line, the data will
provide a source for further studies on the subject.
Acknowledgements: The authors would like to thank Prof.
Dr. Ayse Elif Erson Benson from the Department of Biological
Sciences, METU for supplying MDA-MB 231 cell lines.
Also, another thank to Associate Professor Mahmut Çerkez
Ergören and Dr. Gülten Tuncel for their support for providing
the culture medium.
Peer-review: Externally peer-reviewed.
Conflict of Interest: All authors declared no conflict of interest.
Financial Support: This study was supported in terms of
equipment and laboratories by DESAM Institute, Faculty of
Medicine and Faculty of Pharmacy of Near East University,
Nicosia, Cyprus.
Authorship contributions: Concept - P.T., G.Ö., A.K.; Design
- P.T., G.Ö.; Supervision - P.T., A.K., İ.Ç.; Materials - İ.Ç.,
H.Ş.; Data collection and/or processing - P.T., G.Ö.; Data
analysis and/or interpretation - P.T., G.Ö.; Literature search -
G.Ö., İ.Ç.; Writing - G.Ö.; Critical review ? P.T., A.K., İ.Ç.