Anti-inflammatory and antioxidant effects of stem bark extracts of maerua angolensis dc (capparaceae)
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Date
JULY, 2016
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Abstract
Maerua angolensis DC of the family Capparaceae is a plant used traditionally for the
treatment of inflammatory conditions such as arthritis, pain, gout, boils and wounds. There is
however very little scientific data on the usefulness of this plant as an anti-inflammatory
agent. This study therefore aims at investigating the anti-oxidant and anti-inflammatory
activities of M. angolensis. The dried powdered stem bark was extracted using solvents of
different polarities to obtain four extracts: 70 % v/v ethanol extract (F1), ethyl acetate extract
(F2), Petroleum ether extract (F3) and petroleum ether-ethyl acetate 1:1 (F4).The
carrageenan-induced paw oedema, carrageenan-induced pleurisy and acetic acid-induced
vascular permeability models were used to assess the possible anti-inflammatory effects of
the extracts. Histamine, serotonin, bradykinin and prostaglandin E2-induced paw oedema was
also used to determine the effect of the extracts on early phase mediators in acute
inflammation. F1, F2 and F3 (30-300 mg kg-1) dose dependently and significantly suppressed
carrageenan induced paw oedema with the highest dose of 300 mg kg-1 giving a maximum
suppression of 73.45 %, 78.4 % and 68.3 % respectively. Neutrophil infiltration and exudate
volumes in carrageenan-induced pleurisy were significantly reduced by F4 (30-300 mg kg-1)
with maximum inhibition of 90.9 % and 64.2 % respectively. F4 also preserved normal
alveolar architecture in rat lungs in the pleurisy assay with reduced neutrophil infiltration,
oedema, hyperaemia and alveolar septal thickening from histopathological assessment.
Myeloperoxidase activity, an indicator of neutrophil infiltration was also significantly
reduced. Vascular permeability was also attenuated by F4 with marked reduction of Evans
blue dye leakage in acetic acid-induced permeability assay. F4 was able to significantly
suppress inflammation induced by serotonin, bradykinin and prostaglandin E2 but not that
induced by histamine.
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The in vitro antioxidant activity of F4 was evaluated with the 2, 2-diphenyl-1-picrylhydrazyl
hydrate (DPPH) scavenging test. Total phenolic content and total antioxidant capacity of F4
was also determined. F4 had DPPH radical scavenging activity (IC50; 0.1088 mg ml-1), total
phenol content (97.24 mg g-1 tannic acid equivalent) and total antioxidant capacity (114.2 mg
g-1 ascorbic acid equivalent). F4 exhibited in vivo antioxidant activity in carrageenan induced
pleurisy by increasing the levels of glutathione, superoxide dismutase and catalase activity
while decreasing lipid peroxidation in lung tissues. The results indicate that Maerua
angolensis is effective in ameliorating inflammation induced by carrageenan and acetic acid.
It also has the potential of increasing the activity of endogenous antioxidant enzymes and also
a free radical scavenger. These findings therefore justify the wide use of Maerua angolensis
in traditional medicine for inflammatory disease conditions.
Description
A thesis submitted in partial fulfillment of the requirements
for the degree of
Master of Philosophy
in the
Department of Pharmacology,
Faculty of Pharmacy and Pharmaceutical Sciences
by
Felix Agyei Ampadu
Kwame Nkrumah University of Science and Technology,
Kumasi
July, 2016