Avaliação da atividade anti-Helicobacter pylori e citotóxica in vitro de extratos orgânicos obtidos das folhas de Encholirium spectabile e Syzygium cumini

Helicobacter pylori is a spiral, Gram negative, mobile, and microaerophilic bacteria recognized as a major cause of gastritis, ulcer, gastric cancer, and gastric low grade, B cell, mucosa – associated lymphoid tissue (MALT) lymphoma, constituting an important microorganism in medical microbiology. Its importance comes from the difficulty of treatment because the requirement of multiple drugs use, besides the increasing emergence of resistant and multiresistant strains to antibiotics used in th e clinic. In order to expand safe and effective therapeutic options , chemical studies on medicinal plants by obtaining extracts, fractions, isolated compounds or essential oils with some biological activity has been intensified . Given the above, the objective was to evaluate the inhi bitory activity of organic extracts derived from Syzygium cumini and Encholirium spectabile, with antiulcer history, and the essential oil, obtained from S. cumini, against H. pylori (ATCC 43504) by the disk diffusion method, for qualitative evaluation, an d determination of minimum inhibitory concentration (MIC) using the broth microdilution method, for quantitative analysis. Also was evaluated the extracts in vitro toxicity by a hemolytic assay using sheep red blood cells, and VERO and HeLa cells using the MTT assay to analyze cell viability. The extracts of both plant used in antimicrobial assays did not inhibit bacterial growth, however the essential oil of S. cumini (SCFO) proved effective, showing MIC value of 205 μg/mL (0.024 % dilution of the original oil). In the hemolytic assay, the same oil shows moderate toxicity, by promote 25% hemolysis at 1000 μg/mL. Regarding the cytotoxicity in cell culture, the SCFO, at 260 μg/mL, affected the cell viability around 80% of HeLa and 50% of VERO cells. So the oi l obtained from S. cumini leaves has antimicrobial activity against H. pylori and cytotoxicity potential, suggesting a source of new molecule drug candidates, since new stages of toxicity in vitro and in vivo, as well, chemical characterization be evaluate d. Moreover, the development of a prospective drug delivery system can result in a prototype to be used in preclinical tests.

PEG-based solid dispersions enhanced the solubility and dissolution of eprosartan mesylate in-vitro

Abstract - This study investigates the effect of solid dispersions prepared from of polyethylene glycol (PEG) 3350 and 6000 Da alone or combined with the non-ionic surfactant Tween 80 on the solubility and dissolution rate of a poorly soluble drug eprosartan mesylate (ESM) in attempt to improve its bioavailability following its oral administration.

INTRODUCTION

ESM is a potent anti-hypertension [1]. It has low water solubility and is classified as a Class II drug as per the Biopharmaceutical Classification Systems (BCS) leading to low and variable oral bioavailability (approximately 13%). [2]. Thus, improving ESM solubility and/or dissolution rate would eventually improve the drug bioavailability. Solid dispersion is widely used technique to improve the water solubility of poorly water-soluble drugs employing various biocompatible polymers. In this study, we aimed to enhance the solubility and dissolution of EMS employing solid dispersion (SD) formulated from two grades of poly ethylene glycol (PEG) polymers (i.e. PEG 3350 & PEG 6000 Da) either individually or in combination with Tween 80.

MATERIALS AND METHODS

ESM SDs were prepared by solvent evaporation method using either PEG 3350 or PEG 6000 at various (drug: polymer, w/w) ratios 1:1, 1:2, 1:3, 1:4, 1:5 alone or combined with Tween 80 added at fixed percentage of 0.1 of drug by weight?. Physical mixtures (PMs) of drug and carriers were also prepared at same ratios. Drug solid dispersions and physical mixtures were characterized in terms of drug content, drug dissolution using dissolution apparatus USP II and assayed using HPLC method. Drug dissolution enhancement ratio (ER %) from SD in comparison to the plain drug was calculated. Drug-polymer interactions were evaluated using Differential Scanning Calorimetry (DSC) and FT-IR.

RESULTS AND DISCUSSION

The in vitro solubility and dissolution studies showed SDs prepared using both polymers produced a remarkable improvement (p<0.05) in comparison to the plain drug which reached around 32% (Fig. 1). The dissolution enhancement ratio was polymer type and concentration-dependent. Adding Tween 80 to the SD did not show further dissolution enhancement but reduced the required amount of the polymer to get the same dissolution enhancement. The DSC and FT-IR studies indicated that using SD resulted in transformation of drug from crystalline to amorphous form.

CONCLUSIONS

This study indicated that SDs prepared by using both polymers i.e. PEG 3350 and PEG 6000 improved the in-vitro solubility and dissolution of ESM remarkably which may result in improving the drug bioavailability in vivo.

Acknowledgments

This work is a part of MSc thesis of O.M. Ali at the Faculty of Pharmacy, Aleppo University, Syria.

REFERENCES

[1] Ruilope L, Jager B: Eprosartan for the treatment of hypertension. Expert Opin Pharmacother 2003; 4(1):107-14

[2] Tenero D, Martin D, Wilson B, Jushchyshyn J, Boike S, Lundberg, D, et al. Pharmacokinetics of intravenously and orally administered Eprosartan in healthy males: absolute bioavailability and effect of food. Biopharm Drug Dispos 1998; 19(6): 351- 6.

Evaluación agronómica y de calidad de 15 híbridos de Brachiaria humidícola (Rendle) Schweick en la zona húmeda de Camoapa, Boaco, Nicaragua

Con el objetivo de evaluar la composición química y producción de biomasa aérea de 15 híbridos de Brachiaria humidicola como criterios de adaptabilidad al trópico húmedo de Nicaragua, y con potencial de inhibir a través de sus exudados radiculares el proceso de nitrificación en el suelo, fue establecido un ensayo con un arreglo de bloques completo al azar en la comunidad Panamérica del municipio de Camoapa. Para el análisis de calidad se realizaron dos muestras de laboratorio en época seca y lluviosa. Como resultado, diez materiales fueron adaptables, cumpliendo cuatro de nueve criterios establecidos. Los materiales con rendimiento superior al producido por el pasto nativo Retana (Ischaemum ciliare) fueron los híbridos (1158 y 0439), con valores de 25 250, 25 000 (kg/ha) respectivamente. Los materiales con proporciones de digestibilidad mayores al 65% digestibilidad invitro de la materia seca (DIVMS), fueron (1245, 1158, 0695, 1171, 0063, 6780, 1231, 0416 y 1249), con valores de 70.24%, 70%, 70%, 69.33%, 68.31%, 68.21%, 68.14%, 67% y 66.85% respectivamente. Los mayores contenidos de fibras neutro detergente (FND) y fibra neutro detergente digestible (FNDD), fue observada en el hibrido (0416) con 80.30%, y 58.35% respectivamente. La fibra acido detergente (FAD) fue mayor el hibrido (0408) con 50.73%. La mayor digestibilidad invitro de la materia seca (DIVMS) fue observada el hibrido (1245) con 70.24%. Únicamente los materiales (0416) y (0697) están por debajo de este estándar del 7% de proteína cruda. Finalmente los materiales adaptados a la zona de Camoapa, fueron el: 0408, 1231, 0416, 0439, 6780, 1158, 1249, 1171, 0695 y el 1245.

In vitro anti-canine distemper virus activity of fucoidan extracted from the brown alga Cladosiphon okamuranus

Canine distemper virus (CDV) is a morbillivirus related to measles virus that infects dogs and other carnivores. CDV has a significant global impact on animal health; however, there is no current antiviral treatment for CDV infection. In recent years, it has been demonstrated that sulfated polysaccharides exhibit antiviral properties both in vivo and in vitro, despite their low cytotoxicity to host cells. Fucoidan is a sulfated polysaccharide found in the cell wall matrix of brown algae. In this study, we evaluated in vitro anti-CDV activity of fucoidan, which was derived from Cladosiphon okamuranus. Fucoidan actively inhibited CDV replication in Vero cells at a 50% inhibitory concentration (IC50) of 0.1 lg/ml. The derived selectivity index (SI50) was[20,000. This polysaccharide likely inhibits viral infection by interference in the early steps and by inhibiting CDV-mediated cell fusion. Fucoidan may be useful in development of pharmacological strategies to treat and control CDV infection.

Expression and purification of tau protein and its frontotemporal dementia variants using a cleavable histidine tag

Recombinant tau protein is widely used to study the biochemical, cellular and pathological aspects of tauopathies, including Alzheimer's disease and frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTPD-17). Pure tau in high yield is a requirement for in vitro evaluation of the protein's physiological and toxic functions. However, the preparation of recombinant tau is complicated by the protein's propensity to aggregate and form truncation products, necessitating the use of multiple, time-consuming purification methods. In this study, we investigated parameters that influence the expression of wild type and FTPD-17 pathogenic tau, in an attempt to identify ways to maximise expression yield. Here, we report on the influence of the choice of host strain, induction temperature, duration of induction, and media supplementation with glucose on tau expression in Escherichia coli. We also describe a straightforward process to purify the expressed tau proteins using immobilised metal affinity chromatography, with favourable yields over previous reports. An advantage of the described method is that it enables high yield production of functional oligomeric and monomeric tau, both of which can be used to study the biochemical, physiological and toxic properties of the protein.

Modelo de gestión para la atención integral de pacientes con enfermedades huérfanas o raras en Colombia

Las enfermedades raras o huérfanas corresponden a aquellas con baja prevalencia en la población, y en varios países tienen una definición distinta de acuerdo con el número de pacientes que afectan en la población. La Organización Mundial de la Salud (OMS), las define como un trastorno que afecta de 650 a 1.000 personas por millón de habitantes, de las que se han identificado alrededor de 7.000. En Colombia su prevalencia es menor de 1 por cada 5.000 personas y comprenden: las enfermedades raras, las ultra-huérfanas y las olvidadas. Los pacientes con este tipo de enfermedades imponen retos a los sistemas sanitarios, pues si bien afectan a un bajo porcentaje de la población, su atención implica una alta carga económica por los costos que involucra su atención, la complejidad en su diagnóstico, tratamiento, seguimiento y rehabilitación. El abordaje de las enfermedades raras requiere un manejo interdisciplinar e intersectorial, lo que implica la organización de cada actor del sistema sanitario para su manejo a través de un modelo que abraque las dinámicas posibles entre ellos y las competencias de cada uno. Por lo anterior, y teniendo en cuenta la necesidad de formular políticas sanitarias específicas para la gestión de estas enfermedades, el presente trabajo presenta una aproximación a la formulación de un modelo de gestión para la atención integral de pacientes con enfermedades raras en Colombia. Esta investigación describe los distintos elementos y características de los modelos de gestión clínica y de las enfermedades raras a través de una revisión de literatura, en la que se incluye la descripción de los distintos actores del Sistema de Salud Colombiano, relacionados con la atención integral de estos pacientes para la documentación de un modelo de gestión integral.