In Vitro Effects of Natural Cocoa Extract on Erythrocyte Membrane and Asexual Erythrocytic Stage of Plasmodium Falciparum
Date
2013-07
Authors
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Publisher
University of Ghana
Abstract
Malaria remains a life-threatening disease in the tropical and sub-tropical world,
affecting mostly children and pregnant women. One of the biggest threats to malaria
control is the ability of the causative parasite to develop resistance to anti-malarials
and how quickly the resistance spreads. This makes it necessary for further research to
discover new anti-malarial drugs. Plant products offer a great promise in this
direction. This study tested the anti-plasmodial activities of crude methanol extract of
natural cocoa powder.
Cold maceration was used to produce the crude cocoa extract and the flavonoids and
phenolic content determined. SYNERGY BRAND (SYBR ® ) Green I assay was used
to determine the in vitro IC 50 of the extract against 3D7 and DD2 strains of
Plasmodium falciparum parasites. Subsequently, the effects of the extract on
erythrocyte membrane integrity and parasite invasion as well as sorbitol-induced
haemolysis were also determined.
The extract tested positive for flavonoids and showed a high total phenolic content
(358.94 mg GAE/g of extract). A stronger inhibitory activity (about 12 fold) against
the 3D7 than DD2 strains (IC 50 values of 51.4 μg/L and 622.6 μg/mL respectively)
was demonstrated. However, pre-treatment of uninfected RBCs with the IC 50
concentration of the extract resulted in 47.3 and 36.0% inhibition of invasion in DD2
and 3D7 strains, respectively. Pre-treating schizont- and late trophozoite-infected
RBCs with the extracts resulted 26.7 % and 17.7 % inhibition of sorbitol-induced
haemolysis in DD2 and 3D7 strains respectively.
The anti-plasmodial activity of the crude methanol natural cocoa extract could be
mainly due to its ability to enhance erythrocyte membrane integrity and protect from
parasite invasion. Erythrocyte membrane integrity enhancement inhibited sorbitol-
induced haemolysis of infected erythrocytes. The direct effects of the bioactive
ingredients of extract on the intracellular parasite could have contributed the
inhibition of sorbitol-induced haemolysis of infected erythrocytes.
It can thus be concluded that crude methanol extract of natural cocoa has anti-
plasmodial activity.
Description
Thesis (MPHIL)-University of Ghana, 2013