Download - Akademi Sains Malaysia

the most effective. The ability to limit oxidant-induced
cell death was not significantly different between 50
µg/mL and 100 µg/mL of the extracts, indicating that
the maximum effective concentration was reached.
The findings on the protective effects of the
extracts against oxidant-induced cell death were
consistent with the moderate antioxidant activities of
the extracts determined by the ABTS radical cation
scavenging assay. Nevertheless, the t-butanol extract
possessed the highest in vitro antioxidant activity,
whereas the ethyl acetate extract was more effective
in limiting oxidant-induced cell death. The ability of
the extracts to scavenge ABTS radical cation implied
that these extracts could act as reactive oxygen
species scavenger in diseases caused by oxidantinduced
cell death. An example of plants which
possess such property is Pogostemon cablin, a wellknown
Korean traditional medicine that has been
proven to be beneficial for patients with cerebral
stroke [12]. The water extract of P. cablin has been
shown to be able to protect the human neuroglioma
cells against necrotic and apoptotic cell death induced
by hydrogen peroxide. The protective effects of the
P. bleo extracts against oxidant-induced cell death
should be investigated further for their potential to
be developed for treatment of neurodegenerative
diseases which can be caused by reactive oxygen
species.
From this study, we can conclude that all of
the crude methanol and fractionated ethyl acetate,
1. Goh K.L. (2000) Malaysian Herbaceous Plants.
Millennium Edition. Advanco Press, Malaysia.
2.
3.
4.
5.
Tan M.L., Sulaiman S.F., Najimuddin N., Samian
M.R. and Tengku Muhammad T.S. (2005) Methanolic
extract of Pereskia bleo (Kunth) DC. (Cactaceae)
induces apoptosis in breast carcinoma, T47-D cell
line. Journal of Ethnopharmacology 96: 287-294.
Er H.M., Cheng E. and Radhakrishnan A.K.
(2007) Anti-proliferative and mutagenic activities
of aqueous and methanol extracts of leaves from
Pereskia bleo (Kunth) DC (Cactaceae). Journal of
Ethnopharmacology 113: 448-456.
Abd Malek S.N., Abdul Wahab N., Yaacob H., Sim
K.S., Hong S.L., Lee G.S. and Rahman S.N.S.A.
(2008) Cytotoxic activity of Pereskia bleo (Cactaceae)
against selected human cell lines. International
Journal of Cancer Research 4: 20-27.
Wahab S.I.A., Abdul A.B., Mohan S.M., Al-Zubairi
A.S., Elhassan M.M. and Ibrahim M.Y. (2009)
REFERENCES
t-butanol and aqueous extracts of the leaves of P.
bleo do not have significant anti-proliferative effect
on both the mouse mammary cancer cells (4T1) and
the normal mouse fibroblast cells (3T3). They are not
cytotoxic, based on the criterion that a crude extract
should have an IC 50 of less than 20 µg/mL for it to
be considered cytotoxic against the treated cells [11].
Nevertheless, the leaf extracts exhibited selectivity in
inhibiting the proliferation of the mouse mammary
cancer cells as opposed to the normal mouse fibroblast
cells. One possible mechanism for the selective killing
of the cancer cells may be related to the ability of the
extracts to activate the p53 function in tumour cells,
causing their growth arrest or apoptosis, as reported
in Ashwagandha (Withania somnifera), a herb
commonly used in Ayurvedic medicine [13]. Among
the extracts tested, the t-butanol extract of the leaves
of P. bleo possesses the highest antioxidant property.
Yet, the antioxidant capacity is only moderate when
compared to other known antioxidant substances
such as green tea leaves and vitamin C. The ability of
the extracts of the leaves of P. bleo in limiting natural
and oxidant-induced cell death in normal mouse
fibroblast cells suggests that the plant may be useful
as a remedy for diseases related to oxidative stress.
Acknowledgement – We would like to thank Taman
Pertanian Malaysia, Universiti Putra Malaysia, for kind
donation of the Pereskia bleo plant. This work was supported
by a grant from the International Medical University.
6.
7.
8.
9.
Biological activities of Pereskia bleo extracts.
International Journal of Pharmacology 5: 71-75.
Lee H.L., Er H.M. and Radhakrishnan A.K. (2009)
In vitro anti-proliferative and antioxidant activities of
stem extracts of Pereskia bleo (Kunth) DC (Cactaceae).
Malaysian Journal of Science 28: 225-239.
Ryter S.W., Kim H.P., Hoetzel A., Park J.W., Nakahira
k., Wang X. and Choi A.M.K. (2007) Mechanisms of
cell death in oxidative stress. Antioxidants and Redox
Signaling 9: 49-89.
Larson R.A. (1988) The antioxidants of higher plants.
Phytochemistry 27: 969-978.
Re R., Pellegrini N., Proteggente A., Pannala A.,
Yang M. and Rice-Evans C. (1999) Antioxidant
activity applying an improved ABTS radical cation
decolorization assay. Free Radical Biology and
Medicine 26: 1231-1237.
Carmichael J., DeGraff W.G., Gazdar A.F., Minna J.D.
and Mitchell J.B. (1987) Evaluation of a tetrazolium-
Jostt vol 6.indd 37 7/22/10 10:09:17 PM
10.
37
Journal of Science and Technology in the Tropics (2010) 6: 31-38