Potent antileishmanial activity of chitosan against Iranian strain of Leishmania major (MRHO/IR/75/ER): In vitro and in vivo assay.

BACKGROUND & OBJECTIVES: Leishmaniasis is one of the major neglected zoonotic parasitic diseases whose treatment and control is very complex. Pentavalent antimonials remain the primary drugs against different forms of leishmaniasis, however, resistance to antimony and its toxic effects has necessitated the development of alternative medications such as use of medicinal plants and natural compounds. The aim of the current study was to assess the in vitro and in vivo activities of chitosan as a natural resource against Leishmania major. METHODS: Low molecular weight chitosan, with 95% degree of deacetylation was melted in normal saline to a final concentration of 50, 100, 200 and 400 µg/ml. Then, the promastigotes of L. major (Iranian strain) were added to the wells of 96-well plate and 20 µl of each concentration was added to the RPMI 1640 medium. Live and dead promastigotes were counted after adding 0.1% eosin stain. The efficacy of the chitosan was also examined in BALB/c mice infected with Iranian strain of L. major. All in vitro experiments were performed in triplicate and the results of in vitro and in vivo tests were compared to the acetic acid and NaOH as negative control and glucantime as positive control. RESULTS: The low molecular weight chitosan was completely effective at concentrations of 100, 200 and 400 µg/ml on promastigotes of L. major after 180 min of application. Moreover, in the in vivo study, the mean size of dermal lesions significantly decreased in the groups treated with the chitosan compared to the control group. INTERPRETATION & CONCLUSION: According to the results of the study, it can be concluded that chitosan is a potent active compound against L. major and could be evaluated as a new antileishmanial drug in the future.

Anti-Toxoplasma activities of methanolic extract of Sambucus nigra (Caprifoliaceae) fruits and leaves / Actividad anti-Toxoplasma de extractos metanólicos de frutos y hojas de Sambucus nigra (Caprifoliaceae)

Toxoplasma gondii is an obligatory intracellular parasite that infects a wide range of warm-blooded animals and humans. Considering the severity of toxoplasmosis, side effects of current treatments, and the contribution of the ethnopharmacological knowledge for the treatment of parasitic infections, the aim of the present study was to investigate the efficacy of methanolic extracts from the fruits and leaves of Sambucus nigra against tachyzoite of T. gondii. For this, fruits and leaves of S. nigra were collected from Mazandaran province, Iran, were dried under the shade, and powdered using a commercial electrical blender. For extractions, methanol was used as solvent. Virulent RH strain of T. gondii was maintained in mice and macrophages containing tachyzoites were aspirated from the peritoneal cavity. Four concentrations (5, 10, 25 and 50mg/mL) of S. nigra extract were incubated with infected macrophages for 30, 60, 120 and 180 minutes and the viability of the tachyzoites were evaluated by trypan blue staining. Results showed that S. nigra fruit extracts at the concentrations of 5 and 10mg/mL killed 100% of T. gondii tachyzoites after 60 and 120 minutes, respectively; and concentrations of 25 and 50mg/mL killed 100% of the tachyzoites after 30 minutes. Additionally, extract of S. nigra leaves, at the concentrations of 5, 10 and 25mg/mL after 180 minutes, and concentration of 50mg/mL after 60 minutes, resulted with the highest efficacy. Our results showed that S. nigra has acceptable efficacy in vitro and the parasiticidal effect of fruit extract was significantly better than leaf extract. However, in vivo efficacy of this extract needs further investigation. Rev. Biol. Trop. 63 (1): 7-12. Epub 2015 March 01.

Toxoplasma gondii es un parásito intracelular obligatorio que infecta a una gran variedad de animales y seres humanos. Teniendo en cuenta la gravedad de la toxoplasmosis, los efectos secundarios de los tratamientos actuales, y la contribución de los conocimientos etnofarmacológicos para el tratamiento de infecciones parasitarias, el objetivo del presente estudio fue investigar la eficacia de los extractos metanólicos de los frutos y hojas de Sambucus nigra contra el taquizoito de T. gondii. Para esto, se recogieron frutos y hojas de S. nigra en la provincia de Mazandaran, Irán, se secaron a la sombra, y se pulverizaron con una batidora eléctrica comercial. Para las extracciones, se empleó metanol como disolvente. La cepa virulenta RH de T. gondii se mantuvo en ratones y los macrófagos con taquizoitos se aspiraron de la cavidad peritoneal. Cuatro concentraciones (5, 10, 25 y 50mg/ mL) de extracto de S. nigra se encubaron con los macrófagos infectados durante 30, 60, 120 y 180 minutos y la viabilidad de los taquizoitos se evaluó mediante tinción con azul de tripano. Los resultados mostraron que los extractos de frutos de S. nigra en las concentraciones de 5 y 10mg/mL mataron al 100% de los taquizoitos de T. gondii después de 60 y 120 minutos, respectivamente; y las concentraciones de 25 y 50mg/mL mataron al 100% de los taquizoitos después de 30 minutos. Además, el extracto de hojas de S. nigra, en concentraciones de 5, 10 y 25mg/mL después de 180 minutos, y una concentración de 50mg/mL después de 60 minutos, resultaron más eficientes. Nuestros resultados mostraron que S. nigra tiene una eficacia aceptable in vitro y el efecto parasiticida del extracto de frutos fue significativamente mejor que el del extracto de hoja. Sin embargo, la eficacia in vivo de este extracto necesita más investigación.