Centros de escritura universitarios: una estrategia para la permanencia estudiantil

PublishedLas universidades colombianas han sido precursoras en la creación de centros y programas de escritura en Latinoamérica, así como en la producción y difusión de estudios sobre su labor. No es casual, entonces, que la iniciativa para la publicación de un nuevo libro haya surgido en el ámbito académico colombiano. Gracias a la convocatoria del Centro de Escritura, Lectura y Oralidad Académica de la Universidad Santiago de Cali (CELOA) nació Centros de escritura universitarios: Una estrategia para la permanencia estudiantil, un libro que reúne investigaciones llevadas a cabo por cinco centros de escritura de universidades colombianas. El título se nutre de la experiencia y de los trabajos de investigadores que desde hace décadas vienen aportando y reflexionando sobre la importancia de la escritura y la lectura para la construcción del saber y la comunicación de ideas. Entre las contribuciones más citadas por los autores de los capítulos se encuentran las de Paula Carlino, quien en su libro Escribir, leer y aprender en la universidad (Fondo de Cultura Económica, 2005) introdujo el concepto de “alfabetización académica”, que ha sido fundamental para desarrollar prácticas y profundizar en los estudios sobre la enseñanza terciaria

Determinación de actividad antioxidante y antimicrobiana de hojas y flores de la especie vegetal Chromolaena scabra (L. f.) R. M. King & H. Rob [recurso electrónico]

98 páginas : gráficasLa resistencia a múltiples sustancias son un problema de salud pública que se observa en Colombia, esto debido al uso indiscriminado de antibióticos y antifúngicos, que ha generado una respuesta de supervivencia en los microorganismos, otro problema de salud pública es el incremento en casos diagnosticados con cáncer, enfermedad que anualmente cobra la vida de más de 33.100 personas en Colombia. En este contexto, se determinó la actividad antioxidante y antimicrobiana de los extractos de hojas y flores de la especie Chromolaena scabra (L. f.) R.M. King & H. Rob., recolectada en el municipio de Sibaté (Cundinamarca). Se obtuvieron extractos con solventes de polaridad creciente éter de petróleo, diclorometano y etanol tanto para hojas como para flores y se les determino la actividad antioxidante por los métodos DPPH* Y ABTS*+ y la actividad antimicrobiana frente a bacterias (Staphylococcus aureus y Escherichia coli) y hongos (Aspergillus niger y Penicillium digitatum). Los extractos etanolicos presentaron alta actividad antioxidante y moderada actividad antimicrobiana frente a S.aureus, A. niger y P.digitatum; ningún extracto presento inhibición frente E.coli. Estos resultados nos indican que la especie Chromolaena scabra (L. f.) R.M. King & H. Rob., presenta alto potencial y se recomienda purificar e identificar el o los metabolitos secundarios responsables de dichas actividadesThe resistance to multiple substances is a public health problem that is observed in Colombia, this due to the indiscriminate use of antibiotics and antifungals, which has generated a survival response in microorganisms, another public health problem is the increase in cases diagnosed with cancer, a disease that annually kills more than 33,100 people in Colombia. In this context, the antioxidant and antimicrobial activity of the extracts of leaves and flowers of the species Chromolaena scabra (L. f.) R.M. King & H. Rob., Collected in the municipality of Sibaté (Cundinamarca). Extracts were obtained with solvents of increasing polarity, petroleum ether, dichloromethane and ethanol for both leaves and flowers, and the antioxidant activity was determined by the DPPH * and ABTS * + methods and the antimicrobial activity against bacteria (Staphylococcus aureus and Escherichia coli). ) and fungi (Aspergillus niger and Penicillium digitatum). The ethanol extracts showed high antioxidant activity and moderate antimicrobial activity against S. aureus, A. niger and P. digitatum; no extract showed inhibition against E. coli. These results indicate that the species Chromolaena scabra (L. f.) R.M. King & H. Rob., Presents high potential and it is recommended to purify and identify the secondary metabolite (s) responsible for said activities.Incluye bibliografí

DETERMINATION OF ANTIMICROBIAL ACTIVITY IN LEAVES AND FLOWERS OF CHROMOLAENA SCABRA (L. F.) R.M. KING AND H. ROB.

Objective: The objective of the study was to determine the antimicrobial activity of leaf and flower extract in Chromolaena scabra (L. f.) R.M. King and H. Rob., against selected strains of bacteria and fungi. Methods: The agar diffusion method with plate perforation was developed; the microorganisms used were strains of Staphylococcus aureus and Escherichia coli, Aspergillus niger, and Penicillium digitatum. Rifampicin was used as a positive control. The evaluation was performed by measuring the diameter of the growth inhibition zones around the holes. The inhibitory effect of the plant extracts was obtained by its efficiency compared to the positive control. A comparison with fluconazole and ketoconazole was performed to determine how much of the extract is required to cause inhibition of fungal growth from the standard. Results: IC50 was determined by relating the ln of mass evaluated with respect to the square of the inhibition halo; ethanolic extracts of leaves and flowers of petroleum ether with IC50 values of 85.8 mg/ml and 50.3 mg/ml showed the highest inhibitory effect against S. aureus; the extract of petroleum ether and ethanol from leaves with IC50 of 64 mg/ml and 60 mg/ml, respectively. They were effective with A. niger. Leaf petroleum ether extract showed the best relative antifungal activity against A. niger with respect to fluconazole equivalent to 459.51 when fluconazole is 1.0. Conclusion: The extracts with high potential to inhibit the growth of microorganisms were determined to be ether flowers of petroleum and ethanol leaf extracts

Anti-oxidant activity of leaves and flowers extracts in chromolaena scabra plant species (L. f.) r.m. king & h. rob

Chromolaena is a genus of phanerogamic plants belonging to the Asteraceae family. They are native to America, from the southern United States to South America (especially Brazil). The species, Chromolaena scabra (L.f.) R.M. King and H. Rob, is registered in Colombia and Ecuador. Objective: The objective of this research was to determine the antioxidant activity of the leaf and flower extracts of Chromolaena scabra. Methods: The antioxidant activity was evaluated by the ABTS*+ cationic radical scavenging method (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) and by the DPPH* radical scavenging test (radical method 1,1-diphenyl-2-picrylhydrazyl); Antioxidant activity tests were performed using Trolox's antioxidant capacity in the ABTS*+ free radical generator and its long-lasting radical scavenging capacity, which is based on the discoloration of the nitrogenous compound DPPH*. Results: The dichloromethane extract has a higher% of free radical uptake evaluated by the DPPH* method, likewise the ethanolic extract has the highest% of free radical uptake by ABTS*+ method; The evaluation of the flower and leaf extracts determined that the extract with the highest IC50 by both methods was ethanol. Conclusion: The antioxidant activity obtained by the DPPH* test was higher than that obtained by the ABTS*+ test, these values are significantly different, however, a good correlation was found between both methods, the results obtained in this study show that Chromolaena scabra has significant potential for use as a natural antioxidant agent

Anti-oxidant activity of leaves and flowers extracts in chromolaena scabra plant species (L. f.) r.m. king & h. rob

Chromolaena is a genus of phanerogamic plants belonging to the Asteraceae family. They are native to America, from the southern United States to South America (especially Brazil). The species, Chromolaena scabra (L.f.) R.M. King and H. Rob, is registered in Colombia and Ecuador. Objective: The objective of this research was to determine the antioxidant activity of the leaf and flower extracts of Chromolaena scabra. Methods: The antioxidant activity was evaluated by the ABTS*+ cationic radical scavenging method (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) and by the DPPH* radical scavenging test (radical method 1,1-diphenyl -2-picrylhydrazyl); Antioxidant activity tests were performed using Trolox's antioxidant capacity in the ABTS*+ free radical generator and its long-lasting radical scavenging capacity, which is based on the discoloration of the nitrogenous compound DPPH* . Results: The dichloromethane extract has a higher% of free radical uptake evaluated by the DPPH* method, likewise the ethanolic extract has the highest% of free radical uptake by ABTS*+ method; The evaluation of the flower and leaf extracts determined that the extract with the highest IC50 by both methods was ethanol. Conclusion: The antioxidant activity obtained by the DPPH* test was higher than that obtained by the ABTS*+ test, these values are significantly different, however, a good correlation was found between both methods, the results obtained in this study show that Chromolaena scabra has significant potential for use as a natural antioxidant agent