In vivo anti-Trypanosoma cruzi activity of hydro-ethanolic extract and isolated active principles from Aristeguietia glutinosa and mechanism of action studies.

The currently available treatments for Chagas disease show limited therapeutic potential and are associated with serious side effects. Attempting to find alternative drugs isolated from Nature as agents against Trypanosoma cruzi has been our goal. Recently, we have demonstrated the in vitro anti-T. cruzi activities of two secondary metabolites isolated from the hydro-ethanolic extract of the aerial parts of Aristeguietia glutinosa (Lam.), (family Asteraceae). These active principles displayed poor hemolytic activity, low toxicity against murine macrophages, and absence of mutagenicity. Herein, proof of concept in vivo studies of the whole hydro-ethanolic extract of the aerial parts of Aristeguietia glutinosa and of the most active component isolated from the hydro-ethanolic extract, i.e., (+)-15-hydroxy-7-labden-17-al, was done in a murine acute model of Chagas disease. Both treatments caused a decrease in the animals' parasitemia. Metabolomic mechanism of action studies were done by 1H-NMR, both on the extract and on the active compounds, examining the effects of the metabolites both on membrane sterol biosynthesis and mitochondrial dehydrogenases, whereby we found that one of the metabolites inhibited the activity of the parasite mitochondrial dehydrogenases and the other inhibited the biosynthesis of parasite membrane sterols. The results are interesting in the context of popular use of plants for the treatment of Chagas disease.

Bioactive-guided identification of labdane diterpenoids from aerial parts of Aristeguietia glutinosa as anti-Trypanosoma cruzi agents.

A bioactive-guided investigation of the hydro-ethanolic extract of aerial parts of Aristeguietia glutinosa Lam. resulted in the isolation of two diterpenoids, (+)-15-hydroxy-labd-7-en-17-al (1) and (+)-13,14,15,16-tetranor-labd-7-en-17,12-olide (2), as the anti-Trypanosoma cruzi active principles. The structures of 1 and 2 were determined by spectroscopic analysis. The hydro-ethanolic extract showed anti-T. cruzi activity (IC50 = 19.6 microg/mL) whereas the isolated compounds 1 and 2 were near to seven- and one and a half-fold (IC50 = 3.0 and 15.6 microg/mL), respectively more active than the original extract. Labdene 1, equipotent as the reference compound (Nifurtimox), displayed low hemolytic activity, low toxicity against murine macrophages, and absence of mutagenicity. These results support the vernacular medicinal use of this plant as an anti-T. cruzi agent.

Lipophilic components from the Ecuadorian plant Schistocarpha eupatorioides.

Phytochemical investigation of secondary metabolites of the Ecuadorian plant Schistocarpha eupatorioides (Fenzl) Kuntze (Asteraceae) afforded three phytyl fatty acid esters along with a mixture of unidentified polyprenols, the very well known sterols beta-sitosterol and stigmasterol, and their corresponding fatty acid esters and glucosyl derivatives. The structures of the compounds were elucidated on the basis of various spectroscopic means. In addition, a volatile fraction was separated the composition of which, comprising sesquiterpene hydrocarbons as the main fraction, was determined by GC-MS.

Screening of South American plants against human immunodeficiency virus: preliminary fractionation of aqueous extract from Baccharis trinervis.

Ethanolic and aqueous extracts of 14 South American medicinal plants were tested for inhibitory activity on human immunodeficiency virus (HIV). Both extracts were relatively non-toxic to human lymphocytic MT-2 cells, but only the aqueous extract of Baccharis trinervis exhibited potent anti-HIV activity in an in vitro MTT assay. To delineate the extract-sensitive phase, some studies of the antiviral properties of the active extract are described in this paper. Based on the results presented here, a separation scheme was devised, which permitted the preliminary fractionation of the extract, with the aim of finding an inhibitor of this virus.

Investigación fitoquímica de plantas con actividad antibacteriana y antimicótica

La investigación fitoquimica fue llevada a cabo paralelamente con la investigación microbiologica, tomado en cuenta la actividad antibacteriana y antimicótica de cada una de las plantas medicinales. Los resultados obtenidos del Screening Fitoquímico Preliminar de las 63 plantas medicinales investigadas, pertenecientes a 28 familias, 49 géneros y 63 especies, son los siguientes: Alcaloides en 20, esteroles en 46, Flavonoides en 23, taninos en 35 Saponinas en 24, Artraquinonas en 18, Heterósidos Cardiotónicos en 8, Sesquiterpenolactonas en 5 y Cumarinas en 9. Se seleccionó cuatro plantas: Monina obtusifolia, Heisteria acuminata, Schinus molle, Baccharis tiendalensis, cuyos extractos totales presentaron una actividad antibacteriana y/o antimicótica excelente para continuar con el fraccionamiento y purificación de metabolitos bioactivos. De aquellas fracciones que tienen actividad antibacteriana y/o antifúngica excelente, se aisló, purificó, y caracterizó metabolitos secundarios que mantienen esta actividad biológica: Bifénilos y Xantonas en Monina obtusifolia y sesquiferpenos y triterpenos en Schinus molle.