Efecto de las membranas con Cu(II) sobre el proceso de filtración y capacidad de biocida contra Escherichia coli / Effect of Cu(II) membranes on the filtration process and biocide capacity against Escherichia coli

Esta investigación estudió la preparación de membranas compuestas de celulosa y quitosano entrecruzadas con Cu(II) para determinar su efecto biocida y eficiencia en la remoción deEscherichia coli. Las membranas de quitosano se obtuvieron por medio de la técnica de evaporación del solvente. Propiedades de absorción de agua, degradación térmica y mecánicas de las membranas fueron evaluadas con el propósito de modificar la estructura química, la superficie y estudiar su impacto como agente biocida. Los resultados muestran que el Cu(II) interactúa con los grupos iónicos de las membranas que inducen un cambio estructural produciendo un aumento de 190% en el módulo G*. Además, el catión provee estabilidad térmica a temperaturas menores de 200 ºC y produce cambios superficiales a la membrana, especialmente a la membrana de celulosa. Adicionalmente, la membrana de celulosa-Cu(II) aumentó su efecto biocida contraE. colihasta un 96%. El proceso de remoción por medio de la filtración aumentó 41% con la incorporación del catión. Esta investigación muestra el efecto de la interacción del catión con grupos iónicos en la membrana que mejoran las propiedades de filtración y efecto biocida contra esta enterobacteria que puede llegar a ser patógena para el ser humano.

This research studied the membrane preparation of Cu(II) crosslinked membranes composed of cellulose and chitosan to determine its biocidal effect and efficiency to remove Escherichia coli. Water absorption, thermal degradation, and G* modulus evaluated the Cu(II) impact on the equilibrium, thermal and mechanical properties. These results showed that Cu(II) incorporation interacts with the ionic groups, inducing a structural change increasing the G* modulus by 190%. Moreover, the cation provides thermal stability at temperatures below 200 ºC and produced surface changes to the membrane, especially to the cellulose mekkmbrane. Additionally, the cellulose-Cu(II) membranes increased 96% their biocidal effect against E. coli. Enterobacter filtration process increased 41% with the cation incorporation into the cellulose membrane. Therefore, this research showed the cation effect on the ionic groups in the membrane that improve the filtration properties and biocidal effect against harmful enterobacteria to humans.

Ethnobotanical, pharmacognostical, pharmacological and phytochemical studies on Smilax domingensis in Guatemala

Smilax domingensis Willd., Smilacaceae, known as zarzaparrilla, is a climbing shrub from Tropical America. The rhizome is popularly used in medicine as anti-inflammatory, antiseptic, and tonic. Since 1983 studies are being conducted in Guatemala for validation of the ethnobotanical uses, particularly in vitro demonstration of antimicrobial activity, using wild material, with high variability and some taxonomic problems. This article reports the taxonomic determination, cultivation of drug material, evaluation of use by in vitro and in vivo pharmacological assays, and phytochemical characterization. Extracts from cultivated material was evaluated by antimicrobial, anti-inflammatory, analgesic and immunomodulatory models, confirming the antimicrobial and immunomodulatory activities. Phytochemistry was done in the crude drug and extracts. Quality control parameters are described (micrographic drawings and phytochemical characteristics). Evidence is presented that cultivated rhizome has antimicrobial and immunomodulatory activities, validating the popular use and helping the industrial development of phytopharmaceutical products.

Subcutaneous antifungal screening of Latin American plant extracts against Sporothrix schenckii and Fonsecaea pedrosoi.

CONTEXT: Subcutaneous mycoses are chronic infections caused by slow growing environmental fungi. Latin American plants are used in folk medicine to treat these afflictions. Moreover, the potential of the rich Latin American biodiversity for this purpose has not been fully explored. OBJECTIVES: The aim of the study was to screen Latin American plant extracts against two species of subcutaneous fungi: Sporothrix schenckii and Fonsecaea pedrosoi. MATERIALS AND METHODS: One hundred ninety-five organic extracts from 151 Latin American plants were screened against two subcutaneous fungi by the agar dilution method at a concentration of 100 µg/mL, and minimum inhibitory concentrations (MICs) of active extracts were determined. Positive (amphothericin B) and negative (50% ethanol) controls were used. RESULTS AND DISCUSSION: Twenty eight extracts showed activity at ≤100 µg/mL. Of these, four extracts from Gnaphalium gaudichaudianum DC (Asteraceae), Plumeria rubra L (Apocynaceae), Tecoma stans (L.) Juss. ex Kunth. (Bignoniaceae), and Trichostigma octandum (L.), H. Walter showed activity against F. pedrosoi at MIC 12.5 µg/mL; and, four extracts from Bourreria huanita (Lex.) Hemsl. (Boraginaceae), Phytolacca bogotensis Kunth (Phytolaccaceae), Monnina xalapensis Kunth (Polygalaceae) and Crataegus pubescens (C. Presl) C. Presl (Rosaceae) against S. schenckii. This is the first report on antifungal activity of the Latin American plants against these two subcutaneous fungi. CONCLUSION: S. schenkii and F. pedrosoi were inhibited by B. huanita (MIC: 12.5 and 25 µg/mL), G. gaudichaudianum (MIC: 50 and 12.5 µg/mL) and T. triflora (MIC: 25 µg/mL).

Comparación de procedimientos macro y micro para evaluar la actividad inhibitoria de hongos y levaduras patógenos al hombre / Comparison of macro and micro methods for evaluating the inhibitory activity of fungi and yeasts pathogenic to man

El tamizaje de la actividad antifúngica permite evidenciar in vitro como un extracto vegetal inhibe el crecimiento de un hongo en condiciones estándar. Actualmente, en la Facultad de Ciencias Químicas y Farmacia se emplea la metodología y tiempo. Como parte de los procesos de globalización, el Comité Nacional para la Estandarización de Laboratorios Clínicos (NCCLS), aprobó la técnica de Microdilución en placa como un estándar para la medición de la actividad antifúngica, la cual haciendo uso de una mínima cantidad de recursos brinda resultados en menor tiempo. A pesar de su aprobación, ésta técnica aún no se aplica en Guatemala para el tamizaje, ni para la determinación de concentración mínima inhibitoria (CIM) de extractos vegetales, razón por la cual el presente estudio tuvo como objetivo comparar ambas técnicas...

Guatemalan plants extracts as virucides against HIV-1 infection.

Prevention methods to avoid transmission of pathogens, including HIV, are crucial in the control of infectious diseases, not only to block epidemic spread but to avoid long-term treatments leading to emergence of resistances and drug associated side effects. Together with vaccine development, the discovery of new virucidal agents represents a research priority in this setting. In the screening of new compounds with antiviral activity, three Guatemalan plant extracts from Justicia reptans, Neurolaena lobata and Pouteria viridis were evaluated with a classic antiviral assay and were found to inhibit HIV replication. This activity was corroborated by an original recombinant virus assay, leading us to perform a deeper study of the virucidal activity. Active fractions were non-toxic in vitro and also inhibited other enveloped viruses. Moreover, these fractions were able to inhibit the transfer of HIV from dendritic cells (DCs) to lymphocytes, that represents the main way of HIV spread in vivo.