The aim of this study was to evaluate extracts from two medicinal plants,
Acanthospermum hispidum
and
Ficus thonningii
, used in traditional medicine in Congo Brazzaville, for
in vitro antiplasmodial activities against two
laboratory strains of
Plasmodium falciparum
: the chloroquine sensitive 3D7 and the chloroquine resistant Dd2. ELISA
HRP2 assay was used to evaluate the
in vitro inhibitory activity of the extracts alone or in combination with
chloroquine. Cytotoxicity was assessed on human HeLa cell line and reflected by the selectivity index. Methanolic
extract of
Acanthospermum hispidum exhibited a strong and a moderate inhibitory activity on the growth of Dd2 and
3D7 at 2.8 μg/ml and 9.2 μg/ml concentrations respectively with a selectivity index >10. The combination of the most
active extract (methanolic extract of
Acanthospermum hispidum) with chloroquine showed a synergistic interaction on
both strains. The good selectivity index of
Acanthospermum hispidum on HeLa cells reflects the safety of this plant.
Extracts from
Ficus thonningii did not show any promising antiplasmodial activity on both 3D7 and Dd2. Except the
methanolic extract which exhibited a slight antiplasmodial activity with inhibitory concentration and selectivity index
corresponding to 9.61 μg/ml and 11.16 respectively. Methanolic extract of
Acanthospermum hispidum exhibited
moderate to high inhibitory activity on 3D7 and Dd2 laboratory strains and a synergistic antimalarial effect when
combined with chloroquine.
Ficus thonningii seems to have no antimalarial activity. Phytochemical analysis,
in vivo
investigations using animal models and later clinical trials in collaboration with traditional practitioners are necessary
to clarify the potential antimalarial activity of both plants.
