Browsing by Autor "Elena E. Stashenko"

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Chemical composition and antiprotozoal activities of Colombian Lippia spp essential oils and their major components
(Instituto Oswaldo Cruz, Ministério da Saúde, 2010) Patricia Escobar; Sandra Milena Leal Pinto; Laura Viviana Herrera; Jairo René Martı́nez; Elena E. Stashenko
The chemical composition and biological activities of 19 essential oils and seven of their major components were tested against free and intracellular forms of Leishmania chagasi and Trypanosoma cruzi parasites as well as Vero and THP-1 mammalian cell lines. The essential oils were obtained from different species of Lippia, a widely distributed genus of Colombian plants. They were extracted by microwave radiation-assisted hydro-distillation and characterised by GC-FID and GC-MS. The major components were geranial, neral, limonene, nerol, carvacrol, p-cymene, gamma-terpinene, carvone and thymol. The essential oil of Lippia alba exhibited the highest activity against T. cruzi epimastigotes and intracellular amastigotes with an IC50 of 5.5 microg/mL and 12.2 microg/mL, respectively. The essential oil of Lippia origanoides had an IC50 of 4.4 microg/mL in L. chagasi promastigotes and exhibited no toxicity in mammalian cells. Thymol (IC50 3.2 +/- 0.4 microg/mL) and S-carvone (IC50 6.1 +/- 2.2 microg/mL), two of the major components of the active essential oils, were active on intracellular amastigotes of T. cruziinfected Vero cells, with a selective index greater than 10. None of the essential oils or major components tested in this study was active on amastigotes of L. chagasi infected THP-1 cells.
Propuesta para seleccionar aceites esenciales de plantas de Colombia para investigación con base en su citotoxicidad
(Universidad de Antioquia, 2016) Sindi Alejandra Velandia; María C. Flechas; Elena E. Stashenko; Raquel E. Ocazionez
Antecedentes: Conocer la tendencia de productos de plantas a causar toxicidad en humanos es parte de la investigacin orientada al descubrimiento de un medicamento natural. Las pruebas en animales son relativamente costosas, de bajo rendimiento, asociadas a sufrimiento del animal y diferencias relativas a la especie hacen difcil inferir efectos en humanos. Las pruebas en clula viva son recomendadas. Objetivo: Estudiar la tendencia a toxicidad de aceites esenciales (AE) de plantas de Colombia usando un ensayo basado en clula. Mtodo: Los AE de 18 especies distintas de plantas fueron estudiados. Se us el ensayo del MTT en seis lneas celulares de humano y animal derivadas de tejido normal y canceroso, las cuales se trataron antes y despus de la proliferacin. Los AE se organizaron en el orden de una agrupacin jerrquica con base en los valores de CC 50 y la sumatoria de la jerarqua ponderada en el panel de clulas (JPi ) se us como indicador de similitud. Cuanto mayor fue el valor de JPi menor fue la tendencia a toxicidad. Resultados: Los AE con valores de CC 50 > 200 g/mL en al menos cinco condiciones experimentales presentaron valores de JPi > 6,0 sugiriendo baja tendencia a toxicidad y fueron en orden descendente (JPi en parntesis): Calycolpus moritzianus (O.Berg) Burret (9,7) < Psidium sartorianum (O. Berg) Nied. (8,9) < Wedelia calycina (6,5) < Lippia micromera Schauer (6,2) Piper haltonii . (6,2). AE con valores de CC 50 < 100 g/mL en cuatro o ms condiciones experimentales presentaron valores JPi < 4.0 sugiriendo alta tendencia a toxicidad y fueron en orden ascendente: Tagetes caracasana Kunth (2,7 -2,8) > Chromolaena odorata (L.) R.M.King & H.Rob. (3,0) > Ageratina aff. popayanensis (Hieron.) R.M.King & H.Rob. (3,1) > Lantana colombiana Lpez-Pal. (3,3) >Turnera disffusa. (3,4). AE de Tagetes caracasana present actividad antiproliferante (CI 50 : 42,2 y 47,9 g/mL) sobre clulas humanas de cncer de crvix. Conclusin: El abordaje metodolgico permiti identificar AE con baja y alta tendencia a toxicidad. Los resultados podran tener valor para predecir actividad in vivo y priorizar muestras para futuras investigaciones.
Virucidal activity of Colombian Lippia essential oils on dengue virus replication in vitro
(Instituto Oswaldo Cruz, Ministério da Saúde, 2010) Raquel E. Ocazionez; Rocío Meneses; Flor Ángela Torres; Elena E. Stashenko
The inhibitory effect of Lippia alba and Lippia citriodora essential oils on dengue virus serotypes replication in vitro was investigated. The cytotoxicity (CC50) was evaluated by the MTT assay and the mode of viral inhibitory effect was investigated with a plaque reduction assay. The virus was treated with the essential oil for 2 h at 37 masculineC before cell adsorption and experiments were conducted to evaluate inhibition of untreated-virus replication in the presence of oil. Antiviral activity was defined as the concentration of essential oil that caused 50% reduction of the virus plaque number (IC50). L. alba oil resulted in less cytotoxicity than L. citriodora oil (CC50: 139.5 vs. 57.6 microg/mL). Virus plaque reduction for all four dengue serotypes was observed by treatment of the virus before adsorption on cell. The IC50 values for L. alba oil were between 0.4-32.6 microg/mL and between 1.9-33.7 microg/mL for L. citriodora oil. No viral inhibitory effect was observed by addition of the essential oil after virus adsorption. The inhibitory effect of the essential oil seems to cause direct virus inactivation before adsorption on host cell.