Production and Characterization of Biocomposite Films of Bacterial Cellulose from Kombucha and Coated with Chitosan.

The purpose of this research is to produce and characterize bacterial cellulose (BC) films coated with chitosan (BC-CH). BC films were produced in a fermentation medium based on Camellia sinensis tea and dextrose (12 days at 25 °C) and subsequently treated with coating-forming solutions (CFSs) based on chitosan (BC-CH 0.5%, BC-CH 1.0%, and BC-CH 1.5%). As a result, the FTIR spectra of BC and BC-CH 1.5% showed the main characteristic bands of cellulose and chitosan. In the physicochemical characterization of the films, it was found that the incorporation of the chitosan coatings did not affect the thickness; however, it decreased the luminosity (L*) and increased redness (a*), yellowness (b*), and opacity (75.24%). Additionally, the light absorption properties in the UV-Vis range were improved. Furthermore, the application of the CFSs increased: the solubility (64.91%), the antimicrobial activity against S. aureus (6.55 mm) and E. coli (8.25 mm), as well as the antioxidant activity (57.71% and 24.57% free radical scavenging activity), and the content of total phenols (2.45 mg GAE/g). Finally, our results suggest that the BC-CH films developed in the present study show a potential application as active packaging material for food.

Comparison of Chemical Composition, Physicochemical Parameters, and Antioxidant and Antibacterial Activity of the Essential Oil of Cultivated and Wild Mexican Oregano Poliomintha longiflora Gray.

Mexican oregano Poliomintha longiflora Gray located in the municipality of Higueras, Nuevo Leon, Mexico was collected during the autumn (September, OCO), winter (January, OCI) and summer (June, OCV) seasons, under cultivation conditions. It was also collected in wild conditions during the autumn (OSO). Essential oil (EO) was extracted from leaves and the color, refractive index and density were reported. The EO yield, antioxidant activity by ORAC assay, thymol and carvacrol concentration and antibacterial activity were statistically compared (p-value = 0.05). Among the various harvests, the highest EO yield, antioxidant activity, thymol and carvacrol content and antibacterial activity against Salmonella Typhi were observed in leaves harvested in autumn. In order to compare wild oregano with cultivated oregano, analyses were performed in the season with the highest essential oil yield and antioxidant activity, recorded in autumn. The main difference found was the ratio of thymol:carvacrol in wild oregano oil, which was 1:8.6, while in cultivated oregano, it was approximately 1:2, which was maintained in all three seasons. The EO on wild conditions showed the best antibacterial activity in Salmonella Typhi. On the other hand, wild and cultivated oregano showed similar antioxidant activity. One advantage of the use of cultivated oregano is that its supply is guaranteed, in contrast to that of wild oregano.

Application of a Multisystem Coating Based on Polymeric Nanocapsules Containing Essential Oil of Thymus Vulgaris L. to Increase the Shelf Life of Table Grapes (Vitis Vinifera L.).

In developing countries, the incidence of postharvest losses reduces the quantity and quality of food for human consumption and causes an economical damage along the food chain, especially, for primary producers. In this study, a multisystem coating (NC-EOt-C) based on pullulan and polymeric nanocapsules containing EO of Thymus vulgaris L. (EOt) was applied to increase the shelf life of table grapes (Vitis vinifera L.). The major components of EOt, chemically characterized by GC-MS, were o-cymene (32.68%), thymol (31.90%), and γ -terpinene (15.69%). The NC-EOt were prepared by nanoprecipitation and showed a particle mean size of 153.9 nm, a polydispersity index of 0.186, a zeta potential of -4.11 mV, and an encapsulation efficiency of 52.81%. The antioxidant capacity (DPPH and ABTS+ methods) of EOt was maintained, or even improved, after its incorporation into NC. The shelf life study showed that grapes having the NC-EOt-C multisystem maintained their characteristics of color, firmness, TA, and SSC for longer time than those without the multisystem. NC-EOt-C multisystem acted as a barrier which reduced the metabolism of fruits. In addition, the compounds of EOt with antimicrobial activity avoided microorganism growth, while those with antioxidant activity reduced the oxidative stress induced during postharvest of grapes. Additionally, the polymeric structure of NC prevented the rapid evaporation of volatile compounds of EOt, increasing then their residence time on the fruit. Our study demonstrated that NC-EOt-C multisystem can be a viable alternative to preserve horticultural products for longer storage periods.

Anti-inflammatory and antimicrobial activity of bioactive hydroxyapatite/silver nanocomposites.

Biomaterials are often used in orthopedic surgery like cavity fillings. However, related complications often require long-term systemic antibiotics, device removal, and extended rehabilitation. Hydroxyapatite/silver (HA/Ag) composites have been proposed as implantation biomaterials owing to the osteogenic properties of hydroxyapatite and to the antimicrobial efficiency of silver. Nevertheless, higher silver concentrations induce cytotoxic effects. The aim of this study was to synthesize and characterize HA/Ag nanocomposites that will allow us to use lower concentrations of silver nanoparticles with better antimicrobial efficiency and anti-inflammatory properties. The characterization of HA/Ag was performed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, and laser diffraction. Bioactivity was evaluated under a simulated body fluid. The viability of osteoblast like-cells (MG-63) was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) and the antimicrobial activity was evaluated by the standard McFarland method. The detection of nitric oxide was measured by a colorimetric assay and the inflammatory cytokines by flow cytometry. We obtained particulate composites of calcium phosphates identified as hydroxyapatite and silver nanoparticles. The bioactivity of the HA/Ag nanocomposites on SFB was confirmed by apatite formations. The viability of MG-63 cells was not affected. We also found antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans owing to the presence of silver nanoparticles at non-cytotoxic concentrations. HA/Ag reduced the release of nitric oxide and decreased the secretion of IL-1 and TNF-α in cells stimulated with Lipopolysaccharide (LPS). In conclusion, the inflammatory and antimicrobial capacity of the HA/Ag nanocomposites, as well as its bioactivity and low cytotoxicity make it a candidate as an implantation biomaterial for bone tissues engineering and clinical practices in orthopedic, oral and maxillofacial surgery.

Studied of Defatted Flour and Protein Concentrate of Prunus serotine and Applications.

Prunus serotine seed, was processed to produce a defatted flour (71.07 ± 2.10% yield) without hydrocyanic acid. The total protein was 50.94 ± 0.64%. According to sensory evaluation of cookies with P. serotine flour, the highest score in overall impression (6.31) was at 50% flour substitution. Its nutritional composition stood out for its protein and fiber contents 12.50% and 0.93%, respectively. Protein concentrate (PsPC) was elaborated (81.44 ± 7.74% protein) from defatted flour. Emulsifying properties of PsPC were studied in emulsions at different mass fractions; ϕ = 0.002, 0.02, 0.1, 0.2, and 0.4 through physicochemical analysis and compared with whey protein concentrate (WPC). Particle size in emulsions increased, as did oil content, and results were reflected in microscope photographs. PsPC at ϕ 0.02 showed positive results along the study, reflected in the microphotograph and emulsifying stability index (ESI) test (117.50 min). At ϕ 0.4, the lowest ESI (29.34 min), but the maximum emulsifying activity index (EAI) value (0.029 m2/g) was reached. WPC had an EAI value higher than PsPC at ϕ ≥ 0.2, but its ESI were always lower in all mass fraction values. PsPC can compete with emulsifiers as WPC and help stabilize emulsions.

In vitro and in vivo Methods for the Evaluation of Natural Products against Dermatophytes.

Dermatomycoses are infections caused by fungi called dermatophytes; these affect 20-25% of the world population and the incidence continues to grow each year. Recently, an alternative for the treatment of these diseases is the use of natural products, thanks to the fact that they possess great chemical diversity and thus biological activity. However, to understand the therapeutic potential of natural products, their microbiological assessment presents certain limitations. Currently, there is no established reference method to determine the antifungal capacity in vitro and in vivo of natural products (i.e., essential oils). This review focuses on describing the various microbiological methods as well as the many adaptations used to evaluate the antifungal activity of natural products both in vitro and in vivo. In addition, the antifungal evaluation of natural products formulated in creams, gels, nanoemulsions, nanocapsules and solid lipid nanoparticles is included.

Polymeric nanoparticles for oral delivery of drugs and vaccines: a critical evaluation of in vivo studies.

Oral drug delivery is the preferred route of administration of drugs. Because of their versatility, nanoparticles often have been investigated for the delivery of a wide number of drugs by this route. This article first examines the physicochemical, pharmaceutical and technological aspects that make nanoparticles a potential oral delivery system for drugs and active biomolecules. Next, upon consideration of in vivo studies, the pharmacokinetic, pharmacological and therapeutic aspects of orally administered nanoparticles are described. Special emphasis is placed on improvement of oral bioavailability of drugs incorporated into nanoparticles. Two main mechanisms involved in enhancing drug absorption are discussed: the protection of drug by nanoparticles against harsh conditions in the gut and the prolongation of gastrointestinal transit of nanoparticles by using bioadhesive polymers. Furthermore, nanoparticle uptake by intestinal cells and oral vaccination by these colloidal carriers are also covered. In this context, the immune responses elicited as well as the protection against pathogens induced by antigen-loaded nanoparticles administered by the oral route are presented. Finally, the main limitations and perspectives of these colloidal carriers as oral drug delivery systems are discussed.

Comparative scale-up of three methods for producing ibuprofen-loaded nanoparticles.

The lack of information related to the scaling-up of technologies used for preparing polymeric nanoparticles (NP) might hinder the introduction of these colloidal carriers into the pharmaceutical market. In the present study, the scale-up of ibuprofen-loaded NP produced by three manufacturing processes--salting-out, emulsification-diffusion and nanoprecipitation--was assessed at pilot-scale by increasing 20-fold the laboratory-batch volume from 60 ml to 1.5l. Eudragit L100-55 and poly(vinyl alcohol) (PVAL) were used as polymer and emulsifying agent, respectively. The influence of the hydrodynamic conditions on the NP characteristics such as mean size, drug content, residual PVAL and morphology was also investigated. At pilot-scale, stirring rates of 790-2000 rpm lead to NP mean sizes ranging from 557 to 174 nm for salting-out and from 562 to 230 nm for emulsification-diffusion. An increase in the stirring rate enhances the droplet break-up phenomenon which leads to the formation of finer emulsion droplets and thus smaller NP. Moreover, the influence of the stirring rate on the mean size of NP can be predicted using a model based on a simple power law. The continuous method used for nanoprecipitation scale-up allows production of NP in a reproducible way over a relatively short time. Finally, for the three methods, NP characteristics were reproduced well at both scales. However, the scale-up process induced a slight reduction in the size and drug loading of NP.