Melatonin in Combination with Albendazole or Albendazole Sulfoxide Produces a Synergistic Cytotoxicity against Malignant Glioma Cells through Autophagy and Apoptosis.

Glioblastoma is the most aggressive and lethal brain tumor in adults, presenting diffuse brain infiltration, necrosis, and drug resistance. Although new drugs have been approved for recurrent patients, the median survival rate is two years; therefore, new alternatives to treat these patients are required. Previous studies have reported the anticancer activity of albendazole, its active metabolite albendazole sulfoxide, and melatonin; therefore, the present study was performed to evaluate if the combination of melatonin with albendazole or with albendazole sulfoxide induces an additive or synergistic cytotoxic effect on C6 and RG2 rat glioma cells, as well as on U87 human glioblastoma cells. Drug interaction was determined by the Chou-Talalay method. We evaluated the mechanism of cell death by flow cytometry, immunofluorescence, and crystal violet staining. The cytotoxicity of the combinations was mainly synergistic. The combined treatments induced significantly more apoptotic and autophagic cell death on the glioma cell lines. Additionally, albendazole and albendazole sulfoxide inhibited proliferation independently of melatonin. Our data justify continuing with the evaluation of this proposal since the combinations could be a potential strategy to aid in the treatment of glioblastoma.

Historical Aspects of Herbal Use and Comparison of Current Regulations of Herbal Products between Mexico, Canada and the United States of America.

Increased life expectancy and high costs of medicines and medical care have led to the use of herbal products. However, these items may contain toxic compounds that have an impact on public health. We will focus on the regulatory aspects and differences of these products marketed in the North American region (USA-Mexico-Canada) from government websites and selected literature. Mexico has an ancestral tradition of using plants for the treatment, improvement, and maintenance of human health as compared with Canada and the USA Currently, the use of herbal products in this region has a regulatory framework. The legal framework in these three countries is related to their history, idiosyncrasies, socio-economic and cultural aspects. Therefore, there are different public policies for herbal products consumed in the region. Mexico has a more specific classification of these products. In Canada, all herbal products are classified as natural health products and the safety and efficacy must be scientifically proven. In the USA, the development of botanical drugs is very recent. In particular, both herbal products classified as food supplements in Mexico and dietary supplements in the USA may have risks in both safety and efficacy.

Evaluation of New Benzimidazole Derivatives as Cysticidal Agents: In Vitro, in Vivo and Docking Studies.

Based on our previous research on cysticidal drugs, we report the synthesis and evaluation of three new benzimidazole derivatives. In these compounds, the amido group was used as a bioisosteric replacement of the ester group. The molecular docking on ß-tubulin revealed that the derivatives interacted through hydrogen bonding with N165, E198 and V236. All compounds showed in vitro activity against Taenia crassiceps cysts. Among them, benzimidazole 3 was found to be the most potent of the series (EC50 0.86 µM). This compound also exhibited the highest probability of binding and the lowest binding free energy score and was therefore selected for in vivo evaluation. Results indicated that the efficacy of compound 3 was comparable to that of the reference drug, albendazole (50.39 vs. 47.16% parasite reduction). Animals treated with compound 3 seemed to tolerate this benzimidazole well, with no changes in behavior, or food and water consumption. These findings are consistent with the in silico prediction results, which indicated low toxicity risks. The pharmacokinetic study showed that the half-life and mean residence time (6.06 and 11.9 h, respectively) were long after oral administration. Together, these results indicate that this new benzimidazole derivative represents a promising structure with cysticidal activity.

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.

Comparison of a high-performance liquid chromatography method for quantification of carbamazepine with chemiluminescent microparticle immunoassay.

Carbamazepine is an antiepileptic drug widely used for the treatment of epilepsy. In the National Institute of Neurology, monitoring has been performed using the technique chemiluminescent microparticle immunoassay (CMIA) in an automated way during the last five years. The aim of this study was to develop a simple and rapid HPLC analytical method coupled to DAD-UV detection for the determination of plasma concentrations of carbamazepine and compare its feasibility with those used in routine analysis. The developed HPLC method was fully validated and the applicability of the proposed method was verified through the analysis of plasma samples of patients and later compared with the quantification of the same plasma samples with the CMIA method. The limit of quantification obtained was 0.5 µg/mL. The mean value for recovery was 99.05% and the coefficient of variation (CV) was 5.6%. The precision and accuracy of this method were within the acceptable limits; inter- and intraday CV values were <10%. The correlation between the CMIA method and the developed HPLC method was very good (r ≈ 0.999). A Bland-Altman plot showed no significant bias between the results. The HPLC-DAD method may be an alternative to determine and monitoring the carbamazepine levels in human plasma or serum. Copyright © 2015 John Wiley & Sons, Ltd.

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.

Murine cysticercosis model: influence of the infection time and the time of treatment on the cysticidal efficacy of albendazole and praziquantel.

In the search of new alternatives for neurocysticercosis treatment, Taenia crassiceps ORF strain cysticerci have been used instead of T. solium for in vitro studies. Up to date, the main criteria for the use of the murine cysticercosis model for drug efficacy evaluation have not been assessed. The aim of the present study was to evaluate the influence of two of the main variables related to the in vivo efficacy: the length of drug treatment and the starting time of treatment after experimental infection, using albendazole (ABZ) and praziquantel (PZQ) as test drugs. Additionally, the relationship between the number of cysts and the parasite weight was assessed. For the study, female BALB/c mice were experimentally infected with T. crassiceps cysts. Three different post-infection periods (10, 20 and 30 days) and three different lengths of treatment with ABZ or PZQ (10, 20 and 30 days) were selected. The efficacy of each treatment was evaluated by comparison with a control group. Our results show that for in vivo efficacy studies, the best time to start the drug treatment is 10 days post-infection and that a minimum of 20 days of treatment is required when ABZ or PZQ are used as positive control. Moreover, in this model the parasite weight can be used as a rapid tool to measure the in vivo drug activity.

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.