Silver Nanoparticles and Their Antibacterial Applications.

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Development of a scalable procedure by a discontinuous crossflow DF/UF to obtain a concentrate of chenopodin from a dead-end centrifugal UF at bench scale.

The aim of this study was to develop a scalable crossflow diafiltration/ultrafiltration procedure for quinoa 11S globulin purification starting at the bench scale using Ultra15 centrifugal filter devices. The electrophoretic profiles of centrifugal ultrafiltration fractions showed a high heterogeneity in the bands, while crossflow ultrafiltration reduced the phenomena of protein sticking to the membrane, avoiding aggregate formation. In the crossflow protein concentration, flux decline curves were studied according to Hermia's fouling mechanisms and the resistance in a series model. High reversible resistance was related to external mechanisms due to complete blockage of the membrane surface followed by cake formation. The crossflow ultrafiltration was the most efficient technique for obtaining 57 kDa chenopodin isolate with higher processing capacity, purity and protein yield. The diafiltration/ultrafiltration process proved to be adequate and easy to handle to scale up the production of the 11S quinoa globulin.

Antioxidant and Anti-Proliferative Activity of Essential Oil and Main Components from Leaves of Aloysia polystachya Harvested in Central Chile.

The aim of this study was to determine, first, the chemical composition of Aloysia polystachya (Griseb) Moldenke essential oil, from leaves harvested in central Chile; and second, its antioxidant and cytotoxic activity. Eight compounds were identified via gas chromatography-mass spectrometry (GC-MS) analyses, with the most representative being R-carvone (91.03%), R-limonene (4.10%), and dihydrocarvone (1.07%). For Aloysia polystachya essential oil, antioxidant assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, ferric reducing antioxidant power (FRAP), and total reactive antioxidant potential (TRAP)) showed good antioxidant activity compared to commercial antioxidant controls; and anti-proliferative assays against three human cancer cell lines (colon, HT-29; prostate, PC-3; and breast, MCF-7) determined an IC50 of 5.85, 6.74, and 9.53 µg/mL, and selectivity indices of 4.75, 4.12, and 2.92 for HT-29, PC-3, and MCF-7, respectively. We also report on assays with CCD 841 CoN (colon epithelial). Overall, results from this study may represent, in the near future, developments for natural-based cancer treatments.