In vitro activities of glycoalkaloids from the Solanum lycocarpum against Leishmania infantum

ABSTRACT Leishmania infantum is an etiologic agent of visceral leishmaniasis. This disease is a neglected disease that can be fatal if not treated and additionally, the few therapeutic option present several drawbacks, including difficult route of administration and toxicity, which turn the search for new therapeutic alternatives necessary. Herein, we evaluated the leishmanicidal in vitro activity of the solanum extract from Solanum lycocarpum A. St.-Hil., Solanaceae, and the isolated alkaloids solasodine, solamargine and solasonine against promastigotes and intracellular amastigotes of L. infantum. Solasodine (IC50-pro = 4.7 µg/ml; IC50-ama = 10.8 µg/ml) and solamargine (IC50-pro = 8.1 µg/ml; IC50-ama = 3.0 µg/ml) exhibited interesting leishmanicidal ativity. Solasonine was approximately four-times (Selective Index 3.7) more selective to the parasite than to the host cells. This data suggest that solasonine might be considered as a potential drug candidate for leishmaniasis treatment.

Effects of the extract and glycoalkaloids of Solanum lycocarpum St. Hill on Giardia lamblia trophozoites.

BACKGROUND: Solanum lycocarpum has great importance for food and medicinal traditional use. Recently, it was also evidenced that extracts of S. lycocarpum St. Hill (Solanaceae) and its glycoalkaloids, solamargine (Sg) and solasonine (Sn), are active against flagellated protozoa. OBJECTIVE: The aim was to assess the effects of the extract of S. lycocarpum and its glycoalkaloids, Sn, and Sg, on Giardia lamblia trophozoites. MATERIALS AND METHODS: A crude extract (96%ethanol) (EB) of fruits of S. lycocarpum was prepared and fractionated by partition with 40%ethanol and n-hexane: Ethyl acetate. Glycoalkaloids, Sn, and Sg were recognized in the ethanol fraction (EF) and further isolated by column chromatography. EB, EF, the isolated Sn and Sg and a mixture (1:1) of both glycoalkaloids were tested on cultures of G. lamblia trophozoites and macrophages. RESULTS: EB, EF and glycoalkaloids of S. lycocarpum showed activity against Giardia (95.0 < Inhibitory concentration 50 [IC50] ≤120.3 µg/mL). The mixture of glycoalkaloids (1:1) was more active (IC50 = 13.23 µg/mL) than each one individually, suggesting a synergic effect. Moreover, the mixture is nontoxic to macrophage cells. CONCLUSION: Results are optimistic concerning the anti-Giardia potential of the mixture Sn + Sg. Further studies, in vitro and in vivo, will be required to consolidate the usefulness of the mixture of Sn + Sg in view of a new therapeutic strategy for giardiasis.

In vitro trypanocidal activity of solamargine and extracts from Solanum palinacanthum and Solanum lycocarpum of Brazilian cerrado.

The present investigation was to evaluate the potential trypanocidal activity of crude ethanolic extract of the fruits of Solanum palinacanthum, Solanum lycocarpum and the glycoalcaloid, solamargine. S. palinacanthum and S. lycocarpum fruit powders were submitted to exhaustively extraction with 96% ethanol and solamargine were isolated from the extract of S. palinacanthum. Both extracts and solamargine were analysed for trypanocidal activity by using MTT colorimetric assay. Extracts of S. palinacanthum showed to be more active (IC50 = 175.9 µg.ml-1) than S. lycocarpum (IC50 = 194.7 µg.ml-1). Solamargine presented a strong activity (IC50 = 15.3 µg.ml-1), which can explain the better activity of the both extracts. Benznidazol (IC50 = 9.0 µg.ml-1) is the only drug used to treat Chagas' disease. These findings demonstrate for the first time that ethanol extracts obtained from both fruits of S. palinacanthum and S. lycocarpum and also solamargine have a potential anti-trypanosomal activity.

Paepalanthus spp: antimycobacterial activity of extracts, methoxylated flavonoids and naphthopyranone fractions

Paepalanthus spp., Eriocaulaceae, are native plants from Brazil known as "sempre-vivas" (everlasting flowers). In this work, we evaluated the potential anti-mycobacterial activity of two methoxylated flavonoids (flavonoid 7-methylquercetagetin and 7-methylquercetagetin-4'-O-β-D-glucopyranoside) isolated and identified from P. latipes and the naphthopyranone fractions from P. bromeliodes ethanolic extracts. The MIC value of 500 µg/mL was verified for all compounds tested against M. tuberculosis H37Rv. For M. avium, the MIC value ranged from 1000-2000 µg/mL excepting to naphthopyranone fractions with MIC of 500 µg/mL. This is the first report of activity determination of Paepalanthus spp. flavonoids activity against Mycobacterium tuberculosis and M. avium.