In Vitro and In Vivo evaluation of the chemopreventive, gastroprotective and wound healing potential of Annona Muricata / Soheil Zorofchian Moghadamtousi
Annona muricata Linn. is a popular fruit tree growing in tropical countries. Its leaves have been extensively employed in folk medicine to treat a variety of ailments and diseases. In this study, anticancer, gastroprotective and wound healing properties of A. muricata leaves and their possible me...
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| Format: | Thesis |
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2016
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| Online Access: | http://studentsrepo.um.edu.my/6586/4/soheil.pdf http://studentsrepo.um.edu.my/6586/ |
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| Summary: | Annona muricata Linn. is a popular fruit tree growing in tropical countries. Its leaves
have been extensively employed in folk medicine to treat a variety of ailments and
diseases. In this study, anticancer, gastroprotective and wound healing properties of A.
muricata leaves and their possible mechanisms of action were determined using in vitro
and in vivo models. Solvent extraction yielded crude ethyl acetate extract (AMEAE),
which demonstrated remarkable cytotoxicity against different cancer cell lines including
A549, HT-29 and HCT-116. Hence, AMEAE anticancer property was investigated
against the respective cell lines. In addition, in vivo chemopreventive potential of
AMEAE was determined against azoxymethane-induced colonic aberrant crypt foci
(ACF) in rats, and AMEAE was subjected to a bioassay-guided approach to isolate the
cytotoxic compound and evaluate its apoptosis-inducing effect. AMEAE was found to
induce mitochondrial-initiated events in cancer cells, as the treated cells shown disruption
of mitochondrial membrane potential, cytochrome c leakage and elevation of Bax
expression. Inversely, Bcl-2 expression was lowered in the treated cells. The following
experiments suggested apoptosis induction in cancer cells, as was reflected by increase in
total nuclear intensity, augmentation in sub-G1 cells, externalization of
phosphatidylserine and activation of initiator (-9) and executioner (-3/7) caspases. These
findings strongly implied that exposure of AMEAE to cancer cells have resulted in
apoptosis induction through the intrinsic pathway. A bioassay-guided investigation on
AMEAE led to the isolation of annonaceous acetogenin, annomuricin E which induced
significant apoptosis-inducing effects in HT-29 cancer cells through mitochondrialmediated
mechanism. The in vivo chemopreventive potential of AMEAE was examined
in five groups of rats, namely negative control, cancer control and AMEAE (250, 500
mg/kg) and positive control (5-fluorouracil). Oral treatment of AMEAE at both doses
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decreased the formation of colonic ACF. The expression of PCNA protein, a marker of
cell proliferation, was downregulated in treated cells and associated with upregulation of
Bax and downregulation of Bcl-2. These results substantiated the traditional use of A.
muricata leaves against cancer and tumors.
The gastroprotective activity of AMEAE at two doses of 1 g/kg and 2 g/kg was examined
against ethanol-induced gastric injury in rats. Gross and histological characterizations
suggested the antiulcerogenic property of AMEAE. Immunostaining revealed
upregulation of Hsp70 protein and downregulation of Bax protein. This activity was
associated with attenuation in oxidative stress evidenced by an increase in the level of
enzymatic antioxidants and nitric oxide and decrease in the level of malondialdehyde.
These findings revealed promising gastroprotective potential for AMEAE, which was
mediated through antioxidant and anti-inflammatory mechanisms.
Wound healing potential of AMEAE (5% w/w and 10% w/w) was evaluated against
excisional wound models in rats. Significant wound healing activity was observed after
topical treatment with AMEAE, assessed by macroscopic and microscopic analyses. This
was associated with a decrease in the number of inflammatory cells, supported by
upregulation in the expression of Hsp70 protein. In addition, level of enzymatic
antioxidants showed augmentation which led to the attenuation in the malondialdehyde
formation. |
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