Análisis fitoquímico y de actividad antimalárica de dos especies del género Cecropia

Abstract

Cecropia metensis Cuatrec. y Cecropia membranaceae Trécul. (familia Cecropiaceae) son especies nativas de Colombia que han sido asociadas con diversas actividades farmacológicas tales como: antihipertensiva, diurética, hipoglicemiante, antiinflamatoria, sedante y antimálarica. La selección de estas especies para el desarrollo de este trabajo tuvo como base la existencia de reportes de actividad antimalárica para plantas del género Cecropia. Empleando hojas con pecíolo de Cecropia metensis y Cecropia membranaceae colectadas en el Departamento del Meta (Colombia) se elaboraron extractos etanólicos, a partir de los cuales se obtuvieron fracciones en éter de petróleo, acetato de etilo, butanol y agua. Los extractos y sus fracciones fueron caracterizados fitoquímicamente y en relación a su actividad in vitro frente a Plasmodium falciparum cepa FCB-2 (cloroquina resistente). Adicionalmente se buscó aportar información para establecer similitudes y diferencias, tanto químicas como de actividad antimalárica, entre las dos especies. Se detectó la presencia de flavonoides, taninos, esteroides y terpenos. Se evidenció la ausencia de alcaloides, saponinas, quinonas, derivados antracénicos, cumarinas y lactonas terpénicas. Los perfiles cromatográficos por cromatografía liquida de alta eficiencia en fase reversa (FR-CLAE), de los extractos, mostraron compuestos de alta, mediana y baja polaridad. En las sub-fracciones éter de petróleo de C. metensis (FECmp4) y de C. membranaceae (FECm4), se identificaron β-sitosterol, γ-sitosterol y estigmasterol. En las subfracciones obtenidas por cromatografía de columna (CC) a través de Sephadex LH-20, a partir de las fracciones butanólicas de las dos especies, se identificaron por CLAE los ácidos protocatéquico y clorogénico, además de los flavonoides rutina y vitexina. Los extractos y fracciones fueron evaluados en el modelo de actividad antiplasmodial in vitro (Ensayo de inhibición de la invasión y desarrollo de Plasmodium falciparum cepa FCB-2). Los extractos etanólicos de C. metensis y C. membranaceae mostraron ser muy poco activos. Las fracciones acetato de etilo de C. metensis (CI50=12.52 μg/mL) y de C. membranaceae (CI50=10.12 μg/mL) fueron activas, de acuerdo con los criterios armonizados por la red “Research Initiative on Traditional Antimalarial - RITAM”. Los resultados obtenidos a partir del estudio preliminar de la actividad antiplasmodial in vitro, sugieren que las fracciones acetato de etilo de C. metensis y de C. membranaceae, son promisorias para futuros ensayos de actividad antimálarica y otros estudios químicos. / Abstract. Cecropia metensis Cuatrec. and Cecropia membranaceae Trécul. (Cecropiaceae family) are Colombian native species that had been associated with several pharmacological activities like antihypertensive, diuretic, hipoglicemic, anti-inflammatory, sedative and antimalarial. The selection of these species for the development of this research was based on the existence of antimalarial activity reports for Cecropia genus species. With petiolated leaves of C. metensis and C. membranaceae collected in the Meta Department (Colombia) were prepared ethanolic extracts, from which were obtained petroleum ether, ethyl acetate, buthanolic and aqueous fractions. These extracts and fractions were phytochemically characterized and evaluated for their in vitro activity against Plasmodiun falciparum FCB-2, chloroquine-resistant strain. Additionally, it was aimed to give information for the chemical and antimalarial activity similarities and differences, between both species. With petiolated leaves of C. metensis and C. membranaceae collected in the Meta Department (Colombia) were prepared ethanolic extracts, from which were obtained petroleum ether, ethyl acetate, buthanolic and aqueous fractions. These extracts and fractions were phytochemically characterized and evaluated for their in vitro activity against Plasmodiun falciparum FCB-2, chloroquine-resistant strain. Additionally, it was aimed to give information for the chemical and antimalarial activity similarities and differences, between both species. There were detected the presence of flavonoids, tannins, steroids and terpenes. It was showed the absence of alkaloids, saponins, quinone, anthracene derivatives, coumarins and terpene lactones. The extracts chromatographic profiles by high reversed phase efficiency liquid chromatography (RP-HPLC) showed high, medium and low polarity substances. In the petroleum ether sub-fractions of C. metensis (FECmp4) and C. membranaceae (FECm4) were identified β-sitosterol, γ-sitosterol and stigmasterol. In the subfractions obtained by column chromatography (CC) using Sephadex LH-20, from the butanolic fraction of both species were identified by HPLC the protocatechuic and chlorogenic acids and flavonoides, rutine and vitexin. The different extracts and fractions were tested in the in vitro model of antiplasmodial activity (inhibition of invasion and development of Plasmodium falciparum strain FCB2 test). C. metensis and C. membranaceae ethanolic extracts showed a very weak activity. The ethyl acetate fractions of C. metensis (CI50=12.52 μg/mL) and C. membranaceae (CI50=10.12 μg/mL) were active, in accordance with the harmonized criteria of the “Research Initiative on Traditional Antimalarial - RITAM” network. The obtained results from the in vitro antiplasmodial activity preliminary study suggest that the C. metensis and C. membranaceae ethyl acetate fractions are promising for future antimalarial activity trials and other chemical studies