Vol.3, No.6, 366-369 (2011) Health
doi:10.4236/health.2011.36062
C
opyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Teucrium polium plant extract provokes significant cell
death in human lung cancer cells
Khadidja Haïdara1, Amal Alachkar2,3, Ala-Eddin Al Moustafa 1,3,4,5*
1Segal Cancer Centre, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada; *Corresponding Author:
2Faculty of Pharmacy/University of Aleppo, Aleppo, Syria;
3Syrian Research Cancer Centre of the Syrian Society against Cancer, Aleppo, Syria;
4Department of Oncology, McGill University, Montreal, Canada;
5Department of Mechanical Engineering, Concordia University, Montreal, Canada.
Received 3 April 2011; revised 19 April 2011; accepted 10 May 2011.
ABSTRACT
Lung cancer is the first common malignancy
worldwide; in view of the limited success of
available treatment modalities for this cancer,
alternative and complementary strategies need
to be developed. On the other hand, Teucrium
polium (TP) is a medicinal plant that has been
used for more than two thousand years for
treating many diseases s uch as abd o minal pain,
indigestion and diabetes in the Middle East.
However, the effect of TP plant extract on hu-
man non-small cell lung cancer (NS CLC) has not
been investigated yet. In this study, we exam-
ined the effects of TP extract on cell prolifera-
tion, cell cycle progression and cell death in
H322 and A549 lung cell lines. Our results show
that TP plant extract inhibits cell proliferation
and deregulates cell cycle progression. More
import antly, TP plant extract causes a dramatic
cell death in both cell lines in comparison with
untreated cells. Our data suggest that this plant
extract could have an important therapeutic role
in the treatment of human NSCLC.
Keywords: Teucrium Polium Plant Extract; Lung
Cancer; Cell Death
1. INTRODUCTION
Lung cancer remains the most common malignancy
worldwide with approximately 1.3 million new cases
and 300,000 deaths each year estimated by the World
Health Organization. In view of the limited success of
available treatment modalities for lung cancer, especially
metastatic forms [1], alternative and complementary
strategies need to be developed. Thus, several topical
studies revealed that the epidermal growth factor-receptor
(EGF-R), a member of the ErbB family of receptor tyro-
sine kinases, has been over-expressed and therefore
identified as a therapeutic target for several human car-
cinomas including non-small cell lung cancer (NSCLC)
[2-4]. Alternatively, we have reported that a ligand-
blocking monoclonal antibody (mAb) against the EGF-R,
LA1, inhibits cell motility of two human NSCLC cell
lines, H322 and A549, which over-express EGF-R. This
is accompanied by restoration of the E-cadherin/catenin
complex which is an important regulator of cell invasion
and metastasis [5-7]. While, EGFR-targeted therapies
have been recently approved using small molecules that
are tyrosine kinase inhibitors (TKI) such as erlotinib and
gefitinib or monoclonal antibodies (cetuximab and pani-
tumumab) which can block receptor dimerization and
activation. However, the response rate to these current
drugs is modest. Therefore, new strategies to treat hu-
man lung carcinomas are still major focus of investiga-
tions.
On the other hand, the medicinal use of plants dates
back to ancient times. Teucrium polium (TP) is a plant
that has been used for over two thousand years in tradi-
tional medicine [8,9]. This plant is widely distributed in
the majority of the Middle East as well as Mediterranean
countries. Earlier studies reported the presence of fla-
vonoids, iridoids and hypoglycemic activity in TP plants
[10-12]. Traditionally TP is used for its antispasmodic
and hypoglycemic activities by the native inhabitants
and is recommended by the herbalists [13,14]. Never-
theless, the effect of the TP plant extract on human lung
cancer remains to be determined. Therefore, in this study,
we examined the effects of TP extract on selected pa-
rameters of human lung cancer cell lines, H322 and
A549.

K. Haïdara et al. / Health 3 (2011) 366-369
Copyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
367367
2. MATERIALS AND METHODS
2.1. Cell Culture
The human lung cancer cell lines H322 and A549
were obtained from the American Type Culture Col-
lection (ATCC). These cell lines were cultured in
Dulbecco modified Eagle’s medium (DMEM) with
5% fetal bovine serum (FBS) and incubated at 37℃ in
a 5% CO2 atmosphere.
2.2. Plant Material and Extract Preparation
The aerial parts of Teucrium polium were collected
from Al-Raka, Syria. The herbs were dried in the shade
and stored in a dark container. Dry plant material was
ground finely and the extract was prepared by boiling
1.5 g of plant material per 50 ml of autoclaved water for
20 min in a covered beaker on a warming plate. The so-
lution was then filtered using 0.45 μm filter [15]. Dilu-
tions of the extracts were prepared in cell culture me-
dium and applied to the cultures.
2.3. Cell Proliferation Assay
Cells (1 × 105/ml) were plated in 6-well dishes in their
regular media (control cells) or containing 100, 150 and
200 μl/ml of TP plant extract. Cells from duplicate wells
were collected by trypsinization, washed and counted
every two days using trypan blue exclusion and hemo-
cytometer. As control, we used another medicinal plant
from Syria, Chamomilla chamomile which did not in-
duce the same affect on cell proliferation and cell cycle
progression in H322 and A549 cell lines.
2.4. Cell Cycle Analysis
H322 and A549 cells were treated with 100, 150 and
200 μl/ml of TP plant extract for two days. Cells were
harvested, washed and fixed and subsequently treated
with 50 μg/ml RNase and stained with 50 μg/ml
propidium iodide for 30 min, then they were analyzed in
a FACS-Calibur and data were evaluated with Cell Quest
and ModFitLT v3.1 software.
3. RESULTS & DISCUSSION
In order to explore the role of TP plant extract as a
potential treatment for human lung carcinomas, we ex-
amined the effect of the aqueous extract of TP, which is
prep ar ed as previously descried by Kandouz et al. [15],
on cell proliferation, cell cycle progression and cell
death in H322 and A549 human lung carcinoma cell
lines. We found that treatment with TP plant extract in-
hibits cell proliferation, deregulates cell cycle progress-
sion, and induces significant cell death in these cell lines
in comparison with untreated (control) cells (data not
shown and Figure 1); it is clear that the treatment with 0,
100, 150 and 200 μl/ml of TP plant extract leads to a
dose-dependent increase in cell death in H322 and A549
cell lines (Figure 1). Thus, this study clearly demon-
strates that TP plant extract provokes cell death in hu-
man NSCLC. While, it has been reported that the TP
plant extract has antioxidant properties [16]; and the
bioactive compounds contained flavonoids and neo-
clerodane diterpenoids [17,18]. Recently, Rajabalian
[19], has revealed that combinations of TP extract and
anticancer drugs such as vincristine and/or doxorubicin
induce a massive apoptosis compared to the effect of
individual drugs in several human cancer cell lines such
as MCF7, A431, SW480 Skmel-3 and EJ; moreover, he
found that combination of those anticancer drugs with
TP plant extract reduce the cytotoxic effects of vincris-
tine and vinblastine on human normal fibroblasts. Re-
cently we demonstrated that the TP plant extract inhibits
cell proliferation of two human prostate cancer cell lines,
PC3 and DU145 cells; however, this inhibition is ac-
companied by a small induction of cell death. On the
other hand, we found that TP extract induces differentia-
tion to an epithelial phenotype “mesenchymal-epithelial

K. Haïdara et al. / Health 3 (2011) 366-369
Copyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
368
Figure 1. Teucrium polium (TP) plant extract induces a significant cell death (Sub-G1) in H322 and
A549 human lung cancer cells. Propidium iodide staining shows a significant increase (P < 0.0001 and
P < 0.001) in the proportion of H322 and A549 cells, respectively, in the Sub-G1 phase of the cell cycle
following 48h of TP-treatment especially with (200 µl/ml) using flow cytometry analysis.
transition”, which is an important event in cell invasion
and metastasis, in human prostate cancer cell lines; thus
TP plant extract causes a dramatic decrease in cell inva-
sion and motility of these cancer cells. These changes
are accompanied by a re-localization of the expression
patterns of E-cadherin and catenins. Moreover, we re-
vealed that this plant extract inhibits the phosphorylation
of β-catenin, via Src dephosphorylation, and conse-
quently converts its role from a transcriptional regulator
to a cell-cell adhesion molecule [15]. In parallel, it is
well established that flavonoid compounds have anti-
cancer property and can induce apoptosis through p53
and other regulators of cell apoptosis [20]. Meanwhile,
flavonoids are present in the TP plant [10]; therefore, we
believe that the cell death induced by TP plant extract
could be related to p53 activation as well as other regu-
lators of cell death and apoptosis.
In conclusion, this is, to the best of our knowledge, the

K. Haïdara et al. / Health 3 (2011) 366-369
Copyright © 2011 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
369369
first study on the effect of TP plant extract in human
NSCLC cells. Moreover, this investigation is the first evi-
dence demonstrating that TP plant extract induces a sig-
nificant cell death of human lung carcinoma cells. There-
fore, we firmly believe that this investigation will have
several clinical implications in the treatment of certain
types of human carcinomas including lung cancer.
4. ACKNOWLEDGEMENTS
We are grateful to Mrs. A. Kassab and Dr. A. Yasmeen for critical
reading of the manuscript. This work is supported by the Canadian
Institutes for Health Research (CIHR) and the Syrian society against
cancer.
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