Resumen El propóleo es una resina que elaboran las abejas Apis mellifera a partir de los exudados de la vegetación. Las propiedades biológicas han sido documentadas. Este estudio evaluó la composición química, actividad antioxidante (con radicales DPPH y ABTS), actividad antihemolítica, antiinflamatoria (sobre eritrocitos humanos) y antibacteriana en Escherichia coli O157:H7, Escherichia coli O157, Staphylococcus aureus y Sallmonella typhimurium en extractos etanólicos de propóleos de sur de Sonora, México. La composición química fue de 16.36 ± 1.93 mg EAG/PS y 42.96 mg EQ/PS de fenoles y flavonoides, respectivamente. Los radicales DPPH y ABTS mostraron valores de 75.65 ± 3.76 y 29.61 ± 0.01 mg ET/gPS respectivamente. Los extractos protegieron hasta en un 49.56 % de la hemólisis por el radical y previnieron la inflamación por arriba del 49 %. Todos los extractos de propóleos mostraron actividad antibacteriana con halos de inhibición de 8 a 11.3 mm y CMI de 1 y 2 mg de extracto/mL. Los resultados obtenidos son la base para el estudio de formulaciones naturales con propóleos del sur de Sonora.

Abstract Propolis is a resin made by Apis mellifera bees from vegetation exudates. Biological properties have been documented. This study evaluated the antioxidant, anti-inflammatory and antibacterial activity of ethanolic extracts from southern Sonora, Mexico propolis. The concentration of total phenols and flavonoids was measured. Antioxidant activity was measured and antihemolytic and anti-inflammatory activity of human erythrocytes was determined. In addition, the activity against Escherichia coli O157:H7, Escherichia coli O157, Staphylococcus aureus and Salmonella typhimurium bacteria was evaluated. The ethanolic extracts presented concentrations of 16.36 ± 1.93 mg EAG/gPS and 42.96 mg EQ/gPS of phenols and flavonoids, respectively. The DPPH and ABTS radicals showed values of 75.65 ± 3.76 and 29.61 ± 0.01 mg ET/gPS respectively, the extracts protected up to 49.56% from hemolysis and prevent cell inflammation up 49%. They also presented antibacterial activity against all the strains evaluated, showing inhibition halos of 8 to 11.3 mm and MIC of 1 and 2 mg of extract/mL. The results are the basis for the study of natural formulations with propolis from southern Sonora.

Resumen El nopal (Opuntia gosseliniana) es considerado un producto alimenticio de interés debido a sus propiedades funcionales, incluyendo su actividad antioxidante. El objetivo de este trabajo fue evaluar las propiedades físico-químicas (color, pH y sólidos solubles totales), actividad antioxidante (DPPH, ABTS y FRAP), contenido de fenoles y flavonoides totales y contenido de betalaínas. Así como la evaluación de la toxicidad sobre Artemia salina de los extractos etanólicos de nopal en dos etapas de coloración: verde y morado. El color fue característico para cada etapa de coloración. No se observaron diferencias significativas en los valores de pH y SST en cada etapa de coloración. El % de humedad fue mayor en nopal verde (81 %) con respecto al nopal morado (76.65 %). Respecto al grado de toxicidad, los extractos de nopal morado presentaron menor toxicidad que los extractos de nopal verde. Los valores más altos para fenoles y flavonoides totales se encontraron en las muestras de color morado, con valores de 2.31 mg EAG/gps y 3.06 mg EQ/gps, respec-tivamente. De igual manera, en la actividad antioxidante se obtuvieron valores más altos en la etapa de color morado en las tres técnicas utilizadas. Por lo que, esta especie de cactácea podría ser una fuente potencial de antioxidantes y pigmentos de interés agroindustrial.

Abstract Nopal (Opuntia gosseliniana) is considered a food product of interest due to its functional properties, including its antioxidant activity. The objective of this work was to evaluate the physical-chemical properties (color, pH and total soluble solids), antioxidant activity (DPPH, ABTS and FRAP), content of total phenols and flavonoids, and betalain content. As well as the evaluation of the toxicity of ethanolic extracts of nopal at two stages of coloration: green and purple. Color was characteristic for each coloration stage. No significant differences were observed in pH and SST values at each coloration stage. The % moisture was higher in green nopal (81 %) compared to purple nopal (76.65 %). Regarding the degree of toxicity, purple nopal extracts showed less toxicity than green nopal extracts. The highest values for total phenols and flavonoids were found in purple samples, with values of 2.31 mg EAG/gps and 3.06 mg EQ/gps, respectively. Similarly, in the antioxidant activity (in the three techniques used) and betalain content, higher values were obtained at the purple color stage. Therefore, this species of cacti could be a potential source of antioxidants and pigments of agro-industrial interest.

Interest in developing novel wound dressings with antibacterial properties elaborated from natural sources continues to grow. In this study, a Tween-80 (T80)-stabilized carvacrol (CAR) emulsion was incorporated into pectin (PEC) membranes at 0 (control), 0.25, 0.50, and 1.00% (v/v). Membranes were obtained by the dry-casting method, characterized by scanning electron microscopy, infrared spectroscopy, and CAR retention (HPLC), and tested for antibacterial activity. The retention percentage of CAR in the membranes ranged from 9.1-13.9%. Infrared spectra analysis indicated changes in the hydrogen bonds of the membranes that suggest an interaction between the polymer matrix and the CAR:T80 emulsion. Microstructural analysis of the membranes showed the presence of hole-like features on the surface (≈ 4-6 µm diameter) that indicate entrapment of the micelles in the matrix (microcapsules). The PEC-CAR membranes exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus, two pathogens commonly associated with wounds and intra-hospital infections.

ABSTRACT: The aim of the study was to evaluate the effect of microemulsions of rosemary (AER) and tea tree (AET) essential oils on human erythrocyte and pathogen bacteria. Microemulsions of each oil were prepared at 8.0% (v/v), 5.0% (v/v) and 2.5% (v/v), and they were tested on human erythrocyte to determine the hemolysis percentage, hemolysis inhibition percentage and the antibacterial capacity against E. coli O157:H7 and S. aureus. All AER microemulsions showed no significant hemolytic activity. On the contrary, AET microemulsions showed hemolytic effect but those in concentrations of 8.0% (≈70 %) and 5.0% (33%) showed the highest effect. In addition, AER microemulsions showed protective effect against free radicals in comparison with the AET microemulsions (p< 0.05). On the other hand, the AET microemulsion at 8.0% showed antibacterial effect against E. coli O157:H7 and S. aureus, and the AER at 8.0% showed antibacterial effect against E. coli O157:H7. The limitation of this study was that nucleated cells were not used to observe the damage of the essential oils on nuclear material. However, the observed damage of erythrocyte’s membrane is depending on type and amount of used oil. Therefore, it can be concluded that the AER microemulsions showed better protective effect of erythrocytes, while AET microemulsions showed better antibacterial effect against the tested bacteria, although with toxic effect on the erythrocytes.

RESUMEN: El objetivo del presente trabajo fue evaluar el efecto de las microemulsiones de aceite esencial de romero (AER) y árbol de té (AET) sobre el eritrocito humano y microorganismos patógenos. Para ello, se elaboraron microemulsiones de AER y AET al 8.0% (v/v), 5.0% (v/v) y 2.5% (v/v). Las microemulsiones fueron probadas sobre el eritrocito humano para determinar el porcentaje de hemólisis, el porcentaje de inhibición de hemólisis y su actividad antibacterial contra E. coli O157:H7 y S. aureus. Las microemulsiones con AER no presentaron actividad hemolítica significativa, caso contrario con las microemulsiones de AET al 8.0% (≈70%) y 5.0% (33%) que presentaron mayor actividad hemolítica. Las microemulsiones de AER protegieron significativamente al eritrocito contra la presencia de radicales libres, en comparación con aquellas de AET (p< 0.05). Además, las emulsiones de AET al 8.0% mostraron efectos antibacterianos contra E. coli O157:H7 y S. aureus mientras que AER al 8.0% solo mostraron efecto contra E. coli O157:H7. La limitante del estudio fue que no utilizamos células nucleadas para establecer si los aceites esenciales dañan el material nuclear. Sin embargo, observamos que el tipo y la cantidad de aceite utilizado pueden tener implicaciones serias sobre la membrana eritrocitaria. Se concluye que las microemulsiones de AER presentaron mejor efecto protector eritrocitario, mientras que las microemulsiones de AET presentaron mejor actividad antibacterial contra las bacterias estudiadas, pero con mayor efecto tóxico sobre el eritrocito.