Guava is a fruit appreciated worldwide for its high content of bioactive compounds. However, it is considered a highly perishable fruit, generally attacked by pathogenic species such as the fungi Colletotrichum gloeosporioides, which causes anthracnosis. To diminish the losses caused by pathogenic fungi, coatings of chitosan (CS) with Ruta graveolens essential oil (RGEO) in different concentrations (0.5, 1.0, 1.5% v/v) were applied in situ and their effects on the physical properties and microbiological quality of the guavas were studied. The CS+RGEO coated fruits exhibited better physicochemical behavior and lower microbiological decay as compared to the uncoated guavas, demonstrating the effectiveness of the coatings, especially those with 1.5% of RGEO content. All the fruits coated had greater acceptance and quality than the controls, being more those with essential oil incorporation. In situ investigation of C. gloesporioides infection of guavas demonstrated that the CS+RGEO coated guavas showed a high percentage of inhibition in the development of anthracnose lesions. In the present investigation, an alternative method has been proposed to extend the stability of the guavas fruit up to 12 days with application in the food industry.
The search for new biocompatible materials that can replace invasive materials in biomedical applications has increased due to the great demand derived from accidents and diseases such as cancer in various tissues. In this sense, four formulations based on polycaprolactone (PCL) and polylactic acid (PLA) incorporated with zinc oxide nanoparticles (ZnO-NPs) and tea tree essential oil (TTEO) were prepared. The sol-gel method was used for zinc oxide nanoparticle synthesis with an average size of 11 ± 2 nm and spherical morphology. On the other hand, Fourier Transformed infrared spectroscopy (FTIR) showed characteristic functional groups for each composite component. The TTEO incorporation in the formulations was related to the increased intensity of the C-O-C band. The thermal properties of the materials show that the degradative properties of the ZnO-NPs decrease the thermal stability. The morphological study by scanning electron microscopy (SEM) showed that the presence of TTEO and ZnO-NPs act synergistically, obtaining smooth surfaces, whereas membranes with the presence of ZnO-NPs or TTEO only show porous morphologies. Histological implantation of the membranes showed biocompatibility and biodegradability after 60 days of implantation. This degradation occurs through the fragmentation of the larger particles with the presence of connective tissue constituted by type III collagen fibers, blood vessels, and inflammatory cells, where the process of resorption of the implanted material continues.
RESUMEN: Se sintetizaron tres nuevos derivados imino-quitosano por condensación entre los grupos amino terminales del quitosano y 4-bromometil-2-hidroxibenzaldehido A 1 , Ácido 4-formil-2-hidroxibenzoico A 2 , y (E)-6-((2-(piridin-2-il)hidrazono)metil)picolinaldehido A 3. Es de destacar en este trabajo que las reacciones fueron llevadas a cabo en medio acuoso empleando condiciones suaves de reacción (70°C). Los nuevos compuestos fueron caracterizados por RMN-1 H, FT-IR, análisis elemental, análisis termo gravimétrico (TGA) y calorimetría diferencial de barrido (DSC). Se realizó un estudio de solubilidad a diferentes valores de pH para los tres compuestos, estableciendo comportamientos diferentes a los obtenidos con el quitosano extraído. Por último, mediante medidas de absorción atómica, se investigó la capacidad de los derivados imino-quitosano en la remoción de iones de metales pesados en agua, tales como Pb(II) y Hg(II), el cual mostró un alto porcentaje de remoción a pH básicos pero uno a pH por debajo de 5. Adicionalmente la naturaleza del sustituyente determinó la solubilidad de los aductos resultantes ampliando así las potenciales aplicaciones de estos derivados de quitosano.
The Cover Feature highlights the Latin American culture with an emblem that is the accordion and how the versatility of the amino group resembles the musical notes that appropriately combined exhibit multiple dynamics in the hydrazones. Each highlighted hydrazone‐based system represents one type of dynamism: conformational (orange), configurational (blue), and constitutional (green). The harmonic box contains the words “amino group” to remark the particularly important role of the N–H group in each of those processes observed in hydrazone‐based molecular and supramolecular systems. The authors thank Alejandro Ijaji for the extraordinary design of the cover, following the concept given by the authors. More information can be found in the Review by M. N. Chaur et al.
Se reporta la síntesis de nuevos complejos metálicos de Co2+ y Fe2+ tipo rejilla que contienen como ligando orgánico una doble hidrazona altamente soluble en solventes orgánicos. Los datos obtenidos de resonancia magnética nuclear (RMN 1H), espectroscopía infrarroja con transformada de Fourier (FT-IR) y análisis elemental indican que los complejos adoptaron una estructura de tipo rejilla. Las propiedades electrónicas de las metalo-rejillas fueron analizadas a través de espectroscopía UV-Vis en cloroformo, metanol y diclorometano. Adicionalmente, se realizaron medidas de voltamperometría cíclica y voltametría de onda cuadrada en DMF. Los complejos exhibieron dos procesos de oxidación atribuidos al ligando orgánico y a varios eventos reductivos que comprometían al ligando y a los centros metálicos, por tanto, la interacción entre la naturaleza del ion metálico y la estructura del ligando fue analizada en detalle. Estos resultados representan un avance en la química de metalo-rejillas no solo por los escasos reportes de propiedades electroquímicas encontrados en la literatura, sino también por el diseño de nuevos ligandos hidrazónicos de alta solubilidad y fácil preparación.
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