In Vitro and In Vivo Antileishmanial Activity of Thioridazine.

INTRODUCTION: Leishmaniasis is a neglected disease with high prevalence and incidence in tropical and subtropical areas. Existing drugs are limited due to cost, toxicity, declining efficacy and unavailability in endemic places. Drug repurposing has established as an efficient way for the discovery of drugs for a variety of diseases. PURPOSE: The objective of the present work was testing the antileishmanial activity of thioridazine, an antipsychotic agent with demonstrated effect against other intracellular pathogens. METHODS: The cytotoxicity for mouse peritoneal macrophages as well as the activity against Leishmania amazonensis, Leishmania mexicana and Leishmania major promastigotes and intracellular amastigotes, as well as in a mouse model of cutaneous leishmaniasis, were assessed. RESULTS: Thioridazine inhibited the in vitro proliferation of promastigotes (50% inhibitory concentration-IC50-values in the range of 0.73 µM to 3.8 µM against L. amazonensis, L. mexicana and L. major) and intracellular amastigotes (IC50 values of 1.27 µM to 4.4 µM for the same species). In contrast, in mouse peritoneal macrophages, the 50% cytotoxic concentration was 24.0 ± 1.89 µM. Thioridazine inhibited the growth of cutaneous lesions and reduced the number of parasites in the infected tissue of mice. The dose of thioridazine that inhibited lesion development by 50% compared to controls was 23.3 ± 3.1 mg/kg and in terms of parasite load, it was 11.1 ± 0.97 mg/kg. CONCLUSIONS: Thioridazine was effective against the promastigote and intracellular amastigote stages of three Leishmania species and in a mouse model of cutaneous leishmaniasis, supporting the potential repurposing of this drug as an antileishmanial agent.

Antileishmanial activity of 5-nitroindazole derivatives.

Background: Currently, there is no safe and effective vaccine against leishmaniasis and existing therapies are inadequate due to high toxicity, cost and decreased efficacy caused by the emergence of resistant parasite strains. Some indazole derivatives have shown in vitro and in vivo activity against Trichomonas vaginalis and Trypanosoma cruzi. On that basis, 20 indazole derivatives were tested in vitro against Leishmania amazonensis. Objective: To evaluate the in vitro activity of twenty 2-benzyl-5-nitroindazolin-3-one derivatives against L. amazonensis. Design: For the selection of promising compounds, it is necessary to evaluate the indicators for in vitro activity. For this aim, a battery of studies for antileishmanial activity and cytotoxicity were implemented. These results enabled the determination of the substituents in the indazole derivatives responsible for activity and selectivity, through the analysis of the structure-activity relationship (SAR). Methods: In vitro cytotoxicity against mouse peritoneal macrophages and growth inhibitory activity in promastigotes were evaluated for 20 compounds. Compounds that showed adequate selectivity were tested against intracellular amastigotes. The SAR from the results in promastigotes was represented using the SARANEA software. Results: Eight compounds showed selectivity index >10% and 50% inhibitory concentration <1 µM against the promastigote stage. Against intracellular amastigotes, four were as active as Amphotericin B. The best results were obtained for 2-(benzyl-2,3-dihydro-5-nitro-3-oxoindazol-1-yl) ethyl acetate, with 50% inhibitory concentration of 0.46 ± 0.01 µM against amastigotes and a selectivity index of 875. The SAR study showed the positive effect on the selectivity of the hydrophilic fragments substituted in position 1 of 2-benzyl-5- nitroindazolin-3-one, which played a key role in improving the selectivity profile of this series of compounds. Conclusion: 2-bencyl-5-nitroindazolin-3-one derivatives showed selective and potent in vitro activity, supporting further investigations on this family of compounds as potential antileishmanial hits.

Amphotericin B is usually underdosed in the treatment of experimental cutaneous leishmaniasis / La anfotericina B normalmente es subdosificada en el tratamiento de la leishmaniasis cutánea experimental

Introduction: Amphotericin B is an effective drug for the treatment of the different clinical forms of leishmaniasis. However, there are reports of its ineffectiveness in animals experimentally infected withLeishmaniaspp. That is why, the objective of the present work was to evaluate the balance of activity-toxicity at amphotericin B doses over 1 mg/kg, so that its use as a positive control antileishmanial drug were adequate. Method: BALB/c mice were experimentally infected withL. amazonensisand treated with amphotericin B by intraperitoneal route at doses from 5 mg/kg to 12.5 mg/kg, beginning 21 days after infection. The size of the lesions and the body weight of the mice were measured for eleven weeks after the commencement of treatment. The number of parasites was also determined three days after the end of treatment. Results: Amphotericin B at 5 mg/kg retarded lesions growth but neither reduced lesion size nor the parasite load at lesion site. Doses of 7.5 mg/kg to 10 mg/kg, every 48 h for 14 days (7 doses) caused a significant reduction of lesion size and parasite load without evident loss of body weight and without signs of toxicity. Amphotericin B at 12.5 mg/kg was more effective but produced unacceptable toxicity. Conclusions: The results support the use of amphotericin B as a positive control drug in BALB/c mice experimentally infected withL. amazonensisat doses of 7.5 mg/kg to 10 mg/kg to achieve an effect comparable to that observed in clinical practice. (AU)

Introducción: La anfotericina B es un fármaco eficaz para el tratamiento de las distintas formas de leishmaniosis. Sin embargo, existen informes sobre su ineficacia en animales de laboratorio infectados experimentalmente conLeishmaniaspp.Es por ello que el objetivo del presente trabajo fue evaluar el balance de actividad-toxicidad a dosis de Anfotericina B superiores a 1 mg/kg, de modo que su uso como fármaco leishmanicida control positivo sea adecuado. Método: Se infectaron experimentalmente ratones BALB/c conL. amazonensisy se trataron con anfotericina B por vía intraperitoneal a dosis desde 5 mg/kg hasta 12,5 mg/kg, comenzando 21 días después de la infección. Durante once semanas a partir del comienzo del tratamiento se evaluó el tamaño de las lesiones y el peso corporal de los ratones. Tres días después de concluido el tratamiento se determinó el número de parásitos en las lesiones. Resultados: La anfotericina B a 5 mg/kg retrasó el crecimiento de las lesiones, pero no redujo su tamaño ni disminuyó significativamente el número de parásitos en la lesión. Dosis de 7,5 mg/kg a 10 mg/kg, cada 48 h durante 14 días (7 dosis) causaron una reducción significativa del tamaño de la lesión y de la carga parasitaria sin pérdida manifiesta de peso corporal y sin signos de toxicidad. La anfotericina B a 12,5 mg/kg fue más eficaz, pero produjo una toxicidad inaceptable. Conclusiones: Los resultados avalan el uso de la anfotericina B como control positivo en ratones BALB/c infectados experimentalmente conL. amazonensisen dosis de 7,5 mg/kg a 10 mg/kg para lograr un efecto comparable al observado en la práctica clínica. (AU)

Actividad anti-leishmanial y citotoxicidad de Jatropha gossypifolia L / Antileishmanial activity and cytotoxicity of Jatropha gossypifolia L

INTRODUCCIÓN: Los extractos acuosos de las hojas de Jatropha gossypifolia L. son utilizados de forma tradicional en el tratamiento de la leishmaniasis. No existen informes concluyentes sobre su efectividad y su citotoxicidad aunque en estudios recientes ha quedado avalada la utilidad de la planta en el tratamiento de la leishmaniasis utilizando otros solventes. MÉTODO: Se determinó la actividad leishmanicida y la citotoxicidad de los extractos acuosos e hidroalcohólicos de las hojas de Jatropha gossypifolia L. utilizando el método de fluorescencia de la resazurina en promastigotes de Leishmania amazonensis y macrófagos peritoneales de ratón Balb/c respectivamente. RESULTADOS: Se obtuvieron unas concentraciones inhibitorias 50 de 0.28 Mig/mL ± 0,15 Mig/mL (n = 3) y 0.59 Mig/mL ± 0,26 Mig/mL (n = 3) para el extracto acuoso e hidroalcohólico respectivamente, aunque no se presentó actividad parasiticida a ninguna de las concentraciones evaluadas. De igual manera las concentraciones citotóxicas 50 obtenidas fueron de 0.91 Mig/mL ± 0,11 Mig/mL (n = 3) y 0.57 Mig/mL ± 0,12 Mig/ml (n = 3).CONCLUSIONES: El extracto acuoso resulta ser más eficaz y menos citotóxico frente a los promastigotes de Leishmania amazonensis. Dichos resultados avalan la utilización tópica de los extractos en su formulación tradicional para el tratamiento de la leishmaniosis cutánea

INTRODUCTION: Aqueous extracts of the leaves of Jatropha gossypifolia L. are traditionally used in the treatment of leishmaniasis. These extracts do not have conclusive reports related to their effectiveness and their cytotoxicity although in recent studies the utility of the plant in the treatment of leishmaniasis using other solvents has been supported. METHOD: The antileishmanial activity and the cytotoxicity of the aqueous and hydroalcoholic extracts of the leaves of Jatropha gossypifolia L. were determined using the resazurine fluorescence method. Both, promastigotes of Leishmania amazonensis and peritoneal macrophages of Balb/c mouse were studied. RESULTS: The half-maximal inhibitory concentration for the aqueous and hydroalcoholic extract was 0.28 Mig/mL ± 0.15 Mig/mL (n = 3) and 0.59 Mig/mL ± 0.26 Mig/mL (n = 3) respectively, although they did not show parasiticide activity at any of the evaluated concentrations. Similarly, the mean cytotoxic concentrations obtained were 0.91 Mig/mL ± 0.11 Mig/mL (n = 3) and 0.57 Mig/mL ± 0.12 Mig/ml (n = 3). CONCLUSIONS: The aqueous extract was more effective and less cytotoxic against Leishmania amazonensis promastigotes. The results obtained support the traditional use of the extracts by topical application in the treatment of cutaneous leishmaniasis

Evaluación de la toxicidad del desodorante RLV en ojos / Evaluation of RLV deodorant toxicity in eyes

Se realizó la evaluación del posible efecto irritante de un formulado (RLV) que se empleará como desodorante y que contiene como principio activo la hexamina, la cual es empleada como antiséptico urinario. Este formulado se aplicó por vía oftálmica en 6 conejos de la raza Nueva Zelandia, durante 7 días. Las valoraciones se basan en las observaciones macroscópicas de los posibles efectos adversos que se presentan en las estructuras oculares. Para esta evaluación nos basamos en el método propuesto por Draize, así como las guías de la OECD, de acuerdo con los resultados obtenidos la forma farmacéutica elaborada a una concentración del 3 (por ciento) para el desodorante, no ocasiona irritación en las estructuras oculares

Evaluación de la toxicidad del desodorante RLV en ojos / Evaluation of RLV deodorant toxicity in eyes

Se realizó la evaluación del posible efecto irritante de un formulado (RLV) que se empleará como desodorante y que contiene como principio activo la hexamina, la cual es empleada como antiséptico urinario. Este formulado se aplicó por vía oftálmica en 6 conejos de la raza Nueva Zelandia, durante 7 días. Las valoraciones se basan en las observaciones macroscópicas de los posibles efectos adversos que se presentan en las estructuras oculares. Para esta evaluación nos basamos en el método propuesto por Draize, así como las guías de la OECD, de acuerdo con los resultados obtenidos la forma farmacéutica elaborada a una concentración del 3 (por ciento) para el desodorante, no ocasiona irritación en las estructuras oculares(AU)