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

Abstract

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 (EC 50 = 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.

Can the Cure for Chagas’ Disease be Found in Nature?

“…The ethanol extract activity was comparable to benznidazole (4), probably due to the identification of polar compounds, known to exhibit antiprotozoal activity such as saponins, flavonoids, and coumarins. In the dichloromethane extract was found the presence of steroids such as diosgenone, which can explain its activity [12]. The cytotoxicity is related to the cell type, although steroids of Solanum species are also important for their cytotoxicity.…”

“…There is an estimative that more than 400,000 individuals are currently infected in nonendemic areas like in USA and European countries [11]. These parasites are primarily transmitted by the bite of triatomine bugs from Triatoma, Rhodnius, and Panstrongylus genus [12].…”

“…Furthermore, the presence of phenolic compounds ( Figure 5) like chlorogenic acid (11), rosmarinic acid (12), and coumarin (13) and flavonoids ( Figure 6) luteolin (14), kaempferol (15), and vitexin (16) in low concentrations may have been responsible for the weak bioactivity of L. paniculata and P. crucis ethanolic extracts against T. cruzi [16].…”

“…Extracts from leaves were reported to have antimalarial activity in vitro against asexual blood forms of protozoan Plasmodium falciparum. Based on this, Londoño and collaborators [12] evaluated the leishmanicidal, tripanocidal, antiplasmodial, and cytotoxic activity of eight extracts from Solanum ovalifolium (cucubo) and Solanum arboreum (hoja hedionda) obtained in different polarities, aiming to contribute to new therapeutic alternatives against protozoan diseases.…”

“…In the light of chemical ecology, the antiparasitic effect of S. lycocarpum in the wild is evident: the largest canid of South America, the maned-wolf (Chrysocyon brachyurus), eats the ripen fruits Figure 5. Active phenolic compounds (11), (12) and (13) from ethanol extracts of L. paniculata and P. crucis.…”