RESUMEN
Introducción. La leishmaniasis es un grave problema de salud pública y aun no existe un tratamiento eficaz para la enfermedad. Por esta razón, es necesario investigar nuevas alternativas terapéuticas. Objetivo. En este trabajo nos propusimos evaluar el efecto parasiticida de un ácido kaurénico (ent-kaur-16-in-19-oico) aislado de la planta superior venezolana denominada Wedelia trilobata(Asteracea) sobre Leishmania (V.) braziliensis in vivo e in vitro. Materiales y métodos. Los estudios in vitro fueron realizados en amastigotes axénicos, promastigotes así como en macrófagos infectados y no infectados, los cuales fueron tratados con dosis entre 25-100 µg/ml del ácido kaurénico. El efecto del compuesto sobre la viabilidad celular fue evaluado utilizando el método de conteo directo en una cámara de Neubauer o hemocitómetro y por el método indirecto utilizando el método de MTT (Metil Tiazol Tetrazolium). Para el ensayo in vivo, se utilizaron ratones Balb/c infectados subcutáneamente en la almohadilla plantar con 1x106 promastigotes de Leishmania (V.) braziliensis; posteriormente los ratonesfueron tratados intraperitonealmente durante una semana con 30 mg del ácido kaurénico por kg de peso, en un volumen de 100 µl de etanol al 10 por ciento. Resultados. Este compuesto mostró un potente efecto parasiticida tanto sobre los amastigotes axénicos como sobre promastigotes con dosis letales 50 (DL50) de 0,25 y 0,78 µg/ml respectivamente, en 24 horas. Se observó una baja toxicidad del compuesto sobre macrófagos de la línea J774G8, con una DL50 de 25µg/ml, manteniéndose una alta viabilidad (70-92 por ciento) de los mismos, y una moderada viabilidad para los macrófagos infectados (37-81 por ciento) con concentraciones menores de 25µg/ml. Adicionalmente, se observó una clara reducción (70 por ciento) en el tamaño de las lesiones de los ratones tratados sin efectos tóxicos aparentes. Conclusión. Los resultados obtenidos indican que este compuesto posee un potente efecto leishm...
Introduction. Leishmaniasis is a global public health problem without adequate treatment options, hence requiring research on new drug development. Objective. Our main objective was the evaluation of a kaurenic acid (ent-kaur-16-in-19-oico), isolated from the Venezuelan plant Wedelia trilobata (Asteracea), on Leishmania (V) braziliensis both in vivo and in vitro. Materials and methods. The in vitro assay was performed using axenic amastigotes and promastigotes as well as infected and uninfected macrophages. Parasites and macrophages were treated with concentrations of the compound varying between 10 and 250 µg/ml. The effect of the compound on cellular viability was evaluated by counting dead and living cells in a hemocytometer and by the colorimetric method using MTT (Methylthiazoletetrazolium). For the in vivo assay, Balb/c mice were infected subcutaneously with 1x106 promastigotes of L.(V.) braziliensis and afterwards treated with a daily dose of 30 mg/kg in 100 µl of kaurenic acid administered by intraperitoneal injection for one week. Results. The compound had a lethal effect on axenic amastigotes and promastigotes with DL50 of 0.25 and 0.78 µg/ml, respectively, in 24 hours. Low toxicity was observed for J774-G8 macrophages with a DL50 of 25 µg/ml and high viability (70-92%), while a moderate viability was observed for infected macrophages (37-81%), with concentrations of 25 µg/ml or less. Additionally, a 70% reduction was observed in the size of the skin lesions in Balb/c mice with no evident toxic effect.
Asunto(s)
Asteraceae , Leishmania , Leishmaniasis/tratamiento farmacológico , Plantas Medicinales , Plantas de TratamientoRESUMEN
INTRODUCTION: Leishmaniasis is a global public health problem without adequate treatment options, hence requiring research on new drug development. OBJECTIVE: Our main objective was the evaluation of a kaurenic acid (ent-kaur-16-in-19-oico), isolated from the Venezuelan plant Wedelia trilobata (Asteracea), on Leishmania (V) braziliensis both in vivo and in vitro. MATERIALS AND METHODS: The in vitro assay was performed using axenic amastigotes and promastigotes as well as infected and uninfected macrophages. Parasites and macrophages were treated with concentrations of the compound varying between 10 and 250 microg/ml. The effect of the compound on cellular viability was evaluated by counting dead and living cells in a hemocytometer and by the colorimetric method using MTT (Methylthiazoletetrazolium). For the in vivo assay, Balb/c mice were infected subcutaneously with 1 x 10(6) promastigotes of L. (V.) braziliensis and afterwards treated with a daily dose of 30 mg/kg in 100 microl of kaurenic acid administered by intraperitoneal injection for one week. RESULTS: The compound had a lethal effect on axenic amastigotes and promastigotes with DL50 of 0.25 and 0.78 microg/ml, respectively, in 24 hours. Low toxicity was observed for J774-G8 macrophages with a DL50 of 25 microg/ml and high viability (70-92%), while a moderate viability was observed for infected macrophages (37-81%), with concentrations of 25 microg/ml or less. Additionally, a 70% reduction was observed in the size of the skin lesions in Balb/c mice with no evident toxic effect. CONCLUSION: The results indicate that this compound has a potent leishmanicidal effect on L. (V.) braziliensis.
