Detils of the Preliminary Studies on Piliostigma thonningii Schum Leaf Extract: Phytochemical Screening and in vitro Antimalarial Activity

Different parts of Piliostigma thonningii Scum (Caesalpinioideae) have been used medicinally. The
roots and twigs have been used locally in the treatment of dysentery, fever, respiratory ailments,
snake bites, hookworm and skin infections in Eastern Nigeria. The leaf extracts have been used for
various ethnomedicinal purposes including the treatment of malaria all over Northern Nigeria. In this
study, we have investigated the inhibitory effects of the crude ethanol and methanol extracts for in
vitro antimalarial activity against chloroquine resistant Plasmodium Falciparum clone (W2-Indo-China
isolates). The aqueous screening using reported methodologies for phytochemical screening and in
vitro test methods, revealed the presence of alkaloids, tannins, saponins, steroid, terpenoids,
flavonoids, cardiac glycosides and anthraquinones. The crude leaf extracts obtained were tested for in
vitro antimalarial activity using chloroquine resistant strain of P. Falciparum clone (W2 – Indochina
isolates). The 50% inhibitory concentrations (IC50) were evaluated after 48 - 72 h contacts between
the extracts and the parasite culture. The 50% inhibitory concentration values for both the crude
amide ethanolic extract and the partially purified methanolic extract lie within the significant level of
activity between 6.20 - 15.06 μg/ml (P = 0.000). While that of chloroquine was 0.316 μg/ml (P =
0.013). This lends scientific credence to the use of the leaves for the treatment of malaria in
ethnomedicine. We therefore recommend that further chemical studies should be intensified to identify
and properly characterize the actual compounds responsible for the observed antiplasmodial activity
as it may offer solution to the recurrent antimalaria resistance.