The chemopotential effect of Annona muricata leaves against azoxymethane-induced
colonic aberrant crypt foci in rats and the apoptotic effect of Acetogenin
Annomuricin E in HT-29 cells: a bioassay-guided approach.
Zorofchian Moghadamtousi S(1), Rouhollahi E(2), Karimian H(2), Fadaeinasab M(3),
Firoozinia M(1), Ameen Abdulla M(2), Abdul Kadir H(1).
(1)Biomolecular Research Group, Biochemistry Program, Institute of Biological
Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
(2)Department of Biomedical Science, Faculty of Medicine, University of Malaya,
Kuala Lumpur, Malaysia.
(3)Department of chemistry, Faculty of Science, University of Malaya, Kuala
Annona muricata has been used in folk medicine for the treatment of cancer and
tumors. This study evaluated the chemopreventive properties of an ethyl acetate
extract of A. muricata leaves (EEAML) on azoxymethane-induced colonic aberrant
crypt foci (ACF) in rats. Moreover, the cytotoxic compound of EEAML (Annomuricin
E) was isolated, and its apoptosis-inducing effect was investigated against HT-29
colon cancer cell line using a bioassay-guided approach. This experiment was
performed on five groups of rats: negative control, cancer control, EEAML (250
mg/kg), EEAML (500 mg/kg) and positive control (5-fluorouracil). Methylene blue
staining of colorectal specimens showed that application of EEAML at both doses
significantly reduced the colonic ACF formation compared with the cancer control
group. Immunohistochemistry analysis showed the down-regulation of PCNA and Bcl-2
proteins and the up-regulation of Bax protein after administration of EEAML
compared with the cancer control group. In addition, an increase in the levels of
enzymatic antioxidants and a decrease in the malondialdehyde level of the colon
tissue homogenates were observed, suggesting the suppression of lipid
peroxidation. Annomuricin E inhibited the growth of HT-29 cells with an IC50
value of 1.62 ± 0.24 μg/ml after 48 h. The cytotoxic effect of annomuricin E was
further substantiated by G1 cell cycle arrest and early apoptosis induction in
HT-29 cells. Annomuricin E triggered mitochondria-initiated events, including the
dissipation of the mitochondrial membrane potential and the leakage of cytochrome
c from the mitochondria. Prior to these events, annomuricin E activated caspase
3/7 and caspase 9. Upstream, annomuricin E induced a time-dependent upregulation
of Bax and downregulation of Bcl-2 at the mRNA and protein levels. In conclusion,
these findings substantiate the usage of A. muricata leaves in ethnomedicine
against cancer and highlight annomuricin E as one of the contributing compounds
in the anticancer activity of A. muricata leaves.
PMID: 25860620 [Indexed for MEDLINE]