In vitro and in vivo cysticidal activity of extracts and isolated flavanone from the bark of Prunus serotina: A bio-guided study.

Currently, neurocysticercosis treatment involves two drugs: albendazole and praziquantel; however, their efficacy is suboptimal and new cysticidal drugs are needed. The present paper reports the cysticidal activity of extracts of the bark from Prunus serotina against Taenia crassiceps cysts and the isolation and identification of the main components of the most active extract. Results showed that all extracts displayed in vitro cysticidal activity (EC50=17.9-88.5µg/mL), being the methanolic the most active and selective. Also, methanolic extract exhibited in vivo efficacy at 300mg/kg which was similar to that obtained with albendazole. Bio-guided fractionation of methanolic extract led the isolation of 2,3-dihydro-5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one (naringenin, NGN), 3,4,5-trimethoxybenzoic acid and 1,3,5-trimethoxybenzene. NGN exhibited in vitro activity, in a time-concentration-dependent manner (EC50=89.3µM]. Furthermore, NGN at a dose of 376.1µmol/kg displayed similar in vivo efficacy than those obtained with albendazole at 188.4µmol/kg. NGN also caused a high level of damage in all parasite tissue in a similar manner than that observed with the methanolic extract. This study represents the first report of the cysticidal properties of the bark of P. serotina. NGN was identified as the main active compound of this specie and other studies are required to explore the potential of this flavanone as cysticidal agent.

Cysticidal activity of extracts and isolated compounds from Teloxys graveolens: In vitro and in vivo studies.

In the search of new alternatives for neurocysticercosis treatment, the cysticidal activity of organic extracts of Teloxys graveolens was evaluated. The in vitro activity of hexane, ethyl acetate and methanol extracts against Taenia crassiceps cysts was tested and the selectivity index relative to human fibroblasts was determined. Subsequently, the in vivo efficacy of the methanolic extract at doses of 200 and 500 mg/kg in the murine cysticercosis model was evaluated. The ultrastructural effects in vitro and in vivo of the methanolic extract were also investigated using scanning electron microscopy. Additionally, a bioassay-guided fractionation for the isolation of the cysticidal components was performed. Our in vitro findings revealed that all extracts exhibited good cysticidal activity with EC50 values from 44.8 to 67.1 µg/mL. Although the ethyl acetate and methanolic extracts displayed low cytotoxicity, the methanolic extract was the most selective. The methanolic extract also showed in vivo efficacy which was similar to that obtained with ABZ. Significant alterations were found on the germinal layer of the cysts, with a high accumulation of granules of glycogen and vacuoles. The bioguided fractionation of methanolic extract led to the isolation of three flavonoids: chrysin, pinocembrin and pinostrobin; among them, pinocembrin was the compound that displayed cysticidal activity. This is the first study which reveals that T. graveolens could be a potential source for cysticidal and non-toxic compounds.

Análisis botánico y químico de la corteza de Uncaria tomentosa (Willd. ex Roemer & Schultes) DC / Botanical and chemical analysis of the bark of Uncaria tomentosa (Willd. Ex Roemer & Schultes) DC

La corteza de Uncaria tomentosa (Willd. ex Roemer & Schultes) DC ("uña de gato"), es utilizada en la medicina tradicional de México para el tratamiento del cáncer. El propósito de este trabajo fue llevar a cabo el análisis químico y botánico de diferentes muestras de corteza de Uncaria tomentosa para concluir acerca de la calidad de las mismas. El análisis botánico consistió en determinar sus características macroscópicas (tamaño, color, características de la superficie, textura, fractura, olor y sabor) y microscópicas (vasos aislados, radios, cristales de oxalato de calcio, células de colénquima, células de parénquima y tubos cribosos). Mediante pruebas histológicas y reacciones químicas cualitativas se detectaron taninos condensados e hidrosolubles y alcaloides, los cuales contribuyen a las actividades inmunoestimulante y anticancerígena de la especie. El análisis químico cuantitativo consistió en la determinación del contenido promedio de alcaloides totales (0.7%), cenizas totales (32.9%), cenizas insolubles en ácido (27.2%), cenizas solubles en agua (25.3%), material extraíble en caliente (3.0%), pérdida por secado (9.6%) y arsénico (0.5 µg/ml). La metodología descrita en este trabajo puede constituir una base para establecer algunos parámetros de calidad de la droga cruda derivada de U. tomentosa, con miras a la elaboración de las monografías tipo OMS.