In vitro and in vivo antimalarial activity and cytotoxicity of extracts and fractions from the leaves, root-bark and stem-bark of Triclisia gilletii.

ETHNOPHARMACOLOGICAL RELEVANCE: To evaluate the in vitro antiplasmodial activity and cytotoxicity, and the in vivo activity of extracts and fractions from the leaves, root-bark and stem-bark of Triclisia gilletii (De Wild) Staner (Menispermaceae), used in traditional medicine against malaria. MATERIALS AND METHODS: The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root-bark of Triclisia gilletii were tested in vitro for their antiplasmodial activity against a Congolese-sensitive strain of Plasmodium falciparum, against the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum, for cytotoxicity against MRC-5 cells, and in vivo in mice infected with Plasmodium berghei berghei. RESULTS: Many samples from the three plant parts exhibited pronounced activity against the Congolese chloroquine-sensitive strain of Plasmodium falciparum with some IC50 values <0.02 µg/ml, and against the K1 strain, with some IC50 <0.25; the selectivity was higher against the Congolese strain. At oral doses of 200 and 400mg/kg body weight in infected mice, the aqueous, 80% methanol and total alkaloid extracts from the three plant parts produced more than 65% and 75% chemosuppression, respectively. The antiplasmodial activity of these three plant parts of Triclisia gilletii can at least in part be attributed to bisbenzylisoquinoline alkaloids, and supports its use for the treatment of uncomplicated malaria in traditional medicine.

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves, stem bark and root bark of Alstonia congensis.

ETHNOPHARMACOLOGICAL RELEVANCE: To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases. MATERIALS AND METHODS: The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well. RESULTS: The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC50 values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC50 values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC50 values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC50>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum. CONCLUSION: These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.