Books by Ximena Chiriboga
Papers by Ximena Chiriboga
Molecules, 2014
The currently available treatments for Chagas disease show limited therapeutic potential and are ... more 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., (+)-15hydroxy-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 1 H-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.
CIENCIA UNEMI
Existen muchas plantas nativas de la amazonia cuyas cualidades fitoquímicas, toxicológicas y sus ... more Existen muchas plantas nativas de la amazonia cuyas cualidades fitoquímicas, toxicológicas y sus posibles efectos terapéuticos no han sido estudiados. Nuestro objetivo fue encontrar en el oriente ecuatoriano plantas que contengan látex y resinas, para estudiar preliminarmente sus características fitoquímicas y toxicológicas con el fin de utilizarlas como embolizantes en el tratamiento de algunas enfermedades. Inicialmente, se buscó en la literatura algunas plantas ubicadas en la región amazónica ecuatoriana que contienen látex o resinas. Se identificaron 33 plantas de las cuales 5 plantas fueron seleccionadas y sus cualidades fitoquímicas y toxicológicas estudiadas. Realizada la prueba de toxicidad aguda y subaguda para un extracto de plantas medicinales de acuerdo al criterio de Williams y a la escala logarítmica de Hill y el análisis fitoquímico empleándose la Marcha Fitoquímica Preliminar y el análisis Cromatográfico de los extractos de látex encontramos que los extractos de Sapo...
Chemistry & biodiversity, 2015
Coussarea macrophylla (Mart.) Müll.Arg. (Rubiaceae) was collected in Ecuador, and the bark was ex... more Coussarea macrophylla (Mart.) Müll.Arg. (Rubiaceae) was collected in Ecuador, and the bark was extracted with AcOEt. Chromatographic separation afforded six novel 3,4-secocycloartane and 3,4-secodammarane triterpenes, named macrocoussaric acids A-F, together with the known metabolites secaubryenol and 3,4-secodammara-4(28),20,24-triene-3,26-dioic acid. The structures of the new compounds were determined on the basis of their spectroscopic data. This is the first report of 3,4-secocycloartane and 3,4-secodammarane triterpenes occurring in a Coussarea species. Macrocoussaric acids A and B (2 and 3, resp.) were found to be moderately cytotoxic against five different tumor cell lines.
The invasion of toxic ferns for the Genus Pteridium adversely affecting bovine breeding has been ... more The invasion of toxic ferns for the Genus Pteridium adversely affecting bovine breeding has been reported in different agricultural regions of the world and particularly in Latin America. This genus is a potential risk to humans by the residuality showed by the toxic components of the plant in meat and milk. The aim of this study was to determine the ptaquiloside levels (Pta) in milk samples from San Miguel de Bolívar municipality, Bolívar Province, Ecuador, using high resolution liquid chromatography. Milk samples were collected from farms contaminated by the ferns Pteridium arachnoideum (Kaulf.) Maxon located in different altitudes. The results showed the presence of ptaquiloside residual levels in 82.76% of the samples analyzed, with a maximum concentration obtained from 2219.67 µg/ml and a mean concentration of 805.42 µg/ml. It was associated that high levels of infestation by the fern P. arachnoideum do not only affect animal health, but also represent a threat to public health...
Natural product communications, 2012
A bioactive-guided investigation of the hydro-ethanolic extract of aerial parts of Aristeguietia ... more 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.
Natural Products, 2005
... 356 Guevara-Aguirre and Chiriboga ... Through their foundation, the Healing Forest Conservanc... more ... 356 Guevara-Aguirre and Chiriboga ... Through their foundation, the Healing Forest Conservancy, Shaman Pharmaceuticals has signed contracts with several Ecua-dorian and Peruvian communities in order to cultivate Croton lechlieri and buy from them the corresponding raw ...
Current Drug Discovery Technologies, 2006
Biological & …, 2002
The control of viral diseases has been the subject of in-tense scientific endeavour, with special... more The control of viral diseases has been the subject of in-tense scientific endeavour, with special attention being de-voted to those having retroviruses as etiological agents, in-cluding acquired immunodeficiency syndrome (AIDS). AIDS is a pandemic immunosuppresive disease ...
Base de dados : LILACS. Pesquisa : 178453 [Identificador único]. Referências encontradas : 1 [ref... more Base de dados : LILACS. Pesquisa : 178453 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. experimental, Documentos relacionados. Id: 178453. ...
Natural product communications, 2011
Phytochemical investigation of secondary metabolites of the Ecuadorian plant Schistocarpha eupato... more 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.
Molecules, 2014
The currently available treatments for Chagas disease show limited therapeutic potential and are ... more 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., (+)-15hydroxy-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 1 H-NMR, both on the extract and on the active compounds,
Phytotherapy Research, 1999
Folk medicinal plants are potential sources of useful therapeutic compounds including some with a... more Folk medicinal plants are potential sources of useful therapeutic compounds including some with antiviral activities. Extracts prepared from 10 South American medicinal plants (Baccharis trinervis, Baccharis teindalensis, Eupatorium articulatum, Eupatorium glutinosum, Tagetes pusilla, Neurolaena lobata, Conyza floribunda, Phytolacca bogotensis, Phytolacca rivinoides and Heisteria acuminata) were screened for in vitro antiviral activity against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV) and poliovirus type 1. The most potent inhibition was observed with an aqueous extract of B. trinervis, which inhibited HSV-1 replication by 100% at 50-200 mg/mL, without showing cytotoxic effects. Good activities were also found with the ethanol extract of H. acuminata and the aqueous extract of E. articulatum, which exhibited antiviral effects against both DNA and RNA viruses (HSV-1 and VSV, respectively) at 125-250 mg/mL. The aqueous extracts of T. pusilla (100-250 mg/mL), B. teindalensis (50-125 mg/mL) and E. glutinosum (50-125 mg/mL) also inhibited the replication of VSV, but none of the extracts tested had any effect on poliovirus replication.
Pharmaceutical Biology, 2003
... Furthermore, the decrease in gastric MPO activity suggests an antiinflamma-tory response. ...... more ... Furthermore, the decrease in gastric MPO activity suggests an antiinflamma-tory response. ... Life Sci 65: 337353. Erdtman H, Novotny L, Romanuk M (1966): Flavonols from the fern Cheilanthes farinosa (Forsk) Kaulf. Tetrahedron, Suppl. 8, Part I: 7174. ...
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Books by Ximena Chiriboga
Papers by Ximena Chiriboga