Antiprotozoal properties of Indonesian medicinal plant extracts

Tithonia diversifolia, Cyclea barbata, Tinospora crispa, Arcangelisia flava, Pycnarrhena cauliflora are plants used in Indonesia for the traditional treatment of malaria. In the search for new antiparasitic drugs, the parts traditionally used of these 5 plants were extracted with ethanol and then fractionated with various solvents and evaluated in vitro against Plasmodium falciparum and also against Babesia divergens and Leishmania infantum. Seven crude plant extracts out of 25 tested displayed high antimalarial activities with IC50 < 5 mu g/ml and in the cases of some of them an interesting selectivity regarding their cytotoxicity against mammalian cells. A. flava appeared to be the most promising antiplasmodial plant with the highest antiplasmodial activity IC50 values less than 3 mu g/ml) and the weakest cytotoxicity. By contrast, only P. cauliflora radix, through its dichloromethane and methanol fractions also demonstrated a high activity against L. infantum, with IC50 values around 3 mu g/ml; their high selectivity index, especially on VERO cells, hypothesises a specific parasiticidal action. Moreover, for all the extracts showing antiplasmodial activity, a positive correlation was demonstrated with antibabesial activity, suggesting that these antiplasmodial extracts could be a potential source of antibabesial compounds. These preliminary results confirm the antiplasmodial interest of some of these plants used in traditional medicine but also their effects on leishmaniasis and babesiosis. Ongoing phytochemical investigations should allow identification of the chemical series responsible for these activities.