Antiprotozoal activity and cytotoxicity of extracts from Solanum arboreum and S. ovalifolium (Solanaceae)

Leishmaniasis, Chagas and Malaria are a major health problem in Latin America. Medicinal plants constitute viable alternatives to conventional medicine in many developing countries. Several Solanum species have shown antimicrobial activity, specifically, Solanum nudum has shown in vitro antimalarial activity. Based on the aforementioned, we determined the antiprotozoal activity and cytotoxicity of alcoholic and non-alcoholic extracts from Solanum arboreum and Solanum ovalifolium. Extracts were obtained by percolation with solvents of different polarity: hexane, dichloromethane, ethyl acetate and ethanol. All extracts were evaluated in vitro for antiprotozoal activity against Leishmania panamensis, Trypanosome cruzi and Plasmodium falciparum. Cytotoxicity was also evaluated. In vitro screening showed that dichloromethane (D2) and ethanol (Et2) extracts of S. arboreum were the most active against all three protozoa tested here (EC50 = 1.2 and 4.6 µg/ml against L. panamensis, 13.3 and 2.7 µg/ml against T. cruzi and 3.0 and 2.9 µg/ml against P. falciparum, respectively). These extract were cytotoxic against human U-937 macrophages (6.1 and 4.4 µg/ml, respectively). Additional studies on toxicity using other cell lines are needed. The activity of the Et2 extract is probably due to the presence of polar compounds such as saponins, flavonoids and coumarins. The activity of D2 extract is probably due to the presence of steroids such as diosgenone. These extracts have potential as a source of compounds for the development of new antiprotozoal therapeutical alternatives and therefore further studies are needed to evaluate and validate the use of the extracts as phytotherapeutics. Key words: Antiprotozoal activity, antileismanial activity, trypanocidal activity, antiplasmodial activity, Solanum arboreum, Solanum ovalifolium, Solanaceae.