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In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine
Forkuo, A.D. Ansah, C. Mensah, K.B. Annan, K. Gyan, B. Theron, A. Mancama, D. Wright, Colin W.
Forkuo, A.D.
Ansah, C.
Mensah, K.B.
Annan, K.
Gyan, B.
Theron, A.
Mancama, D.
Wright, Colin W.
Publication Date
2017-12
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© The Author(s) 2017. This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License
(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
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article, unless otherwise stated.
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openAccess
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2017-12-18
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Abstract
Background: Discovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination
and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial
plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study
investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates
the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations
continues.
Methods: The resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta
and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method
based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine
with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7.
Results: Cryptolepis sanguinolenta (
IC50 = 49.65 nM) and its major alkaloid, cryptolepine (
IC50 = 1965 nM), showed
high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual
stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean ΣFIC50s of
1.017 ± 0.06 and 1.465 ± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant
concentration ratios showed a synergistic effect (mean ΣFIC50 = 0.287 ± 0.10) whereas an antagonistic activity (mean
ΣFIC50 = 4.182 ± 0.99) was seen with mefloquine.
Conclusions: The findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and
cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages
of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose
combinations.
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Citation
Forkuo AD, Ansah C, Mensah KB et al (2017) In vitro anti-malarial interaction and
gametocytocidal activity of cryptolepine. Malaria Journal. 16: 496.
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