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The use of antioxidants such as curcumin (Cur) or quercetin (Que) in biomedical and biotechnological applications has been studied owing to their capability to prevent oxidative stress and inhibit free radicals. Using polyhydroxybutyrate (PHB) electrospun fibers is presented as a proper option to encapsulate curcumin and quercetin due to its biocompatibility and biodegradability characteristics. Electrospun fibers were obtained dissolving commercial PHB in chloroform: N , N -dimethylformamide (DMF) (4:1) at 7% m/V, and adding two different concentrations of antioxidant (Cur, and Que) 1%m/m, and 7% m/m. These polymeric solutions were electrospun at different conditions and the obtained fibers were characterized by scanning electron microscopy (SEM), thermogravimetric (TGA) analysis, and Fourier transform infrared spectroscopy (FT-IR). The curcumin and quercetin releases into phosphate buffer saline (PBS) at pH 7.4 were obtained in vitro and measured by spectrophotometry. Antioxidant activities were measured by spectrophotometry in a microplate reader using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Fibers obtained with different formulations presented a chemical composition in accordance with PHB according to FTIR spectra, the diameters fluctuate between 0.761 ± 0.123 and 1.803 ± 0.557 μm, with qualities over 0.95 according to their morphology, and the melting temperature resulted near 178 °C according to the bibliography. The crystallinity of fibers decreases while curcumin or quercetin concentration increases for the studied interval, indeed, quercetin showed a higher impact on the relative crystallinity of fibers. Antioxidant activity of active compounds is maintained after encapsulation in PHB electrospun fibers, and quercetin resulted in near four times antioxidant activity compared to curcumin according to DPPH analysis. • PHB is suitable for carrying quercetin and curcumin. • High quality and solvent-free microfibers are produced with PHB and antioxidants. • Antioxidant characteristics are maintained for the new material. [ABSTRACT FROM AUTHOR]

Abstract Polyhydroxyalkanoates (PHA) are natural polyesters produced by microorganisms under carbon source excess and limiting nutrient conditions. However, these biopolymers possess low mechanical and thermal properties, decreasing their potential applications in the medical field. Electrospinning is a technique that forms fibers from different polymers. PHA electrospun fibers improve the mechanical properties and decrease the crystallinity of PHA, including poly-3-hydroxybutyrate and its copolymers, which is attributed to the metastable structure (β-form) formation. Therefore, the mechanical properties of fibers are intrinsically related to their plane orientation. Aligned fibers present better mechanical properties than randomly oriented fibers. However, randomly oriented fibers promote cell-fiber interaction and cell infiltration. Fibers produced with PHA blended with other polymers have shown improved mechanical and biological properties. Gelatin, zein and cellulose acetate are the main natural polymers that have been blended with PHA for electrospun scaffolds. For scaffold production by coaxial electrospinning, gelatin has been used as a shell and PHA as the core. PHA have been combined with different synthetic polymers and plasticizers resulting in an increase in the PHA miscibility. Therefore, the use of electrospinning in the development of PHA-based scaffolds seems to be an attractive method to change the intrinsic polymer features, increasing and enhancing PHA applications in tissue engineering. [ABSTRACT FROM AUTHOR]

Coaxial electrospinning was used to develop gallic acid (GA) loaded poly(ethylene oxide)/zein nanofibers in order to improve its chemopreventive action on human gallbladder cancer cells. Using a Plackett-Burman design, the effects of poly(ethylene oxide) and zein concentration and applied voltage on the diameter and morphology index of nanofibers were investigated. Coaxial nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). GA loading efficiency as high as 77% was obtained under optimal process conditions. The coaxial nanofibers controlled GA release in acid and neutral pH medium. Cytotoxicity and reactive oxygen species (ROS) production on gallbladder cancer cell lines GB-d1 and NOZ in the presence of GA-nanofibers were assessed. GA-nanofibers triggered an increase in the cellular cytotoxicity compared with free GA on GB-d1 and NOZ cells. Statistically significant differences were found in ROS levels of GA-nanofibers compared with free GA on NOZ cells. Differently, ROS production on GB-d1 cell line was similar. Based on these results, the coaxial nanofibers obtained in this study under optimized operational conditions offer an alternative for the development of a GA release system with improved chemopreventive action on gallbladder cancer cells. [ABSTRACT FROM AUTHOR]

Nano- and microfibers obtained by electrospinning have attracted great attention due to its versatility and potential for applications in diverse technological fields. Polyhydroxyalkanoates (PHAs) are biopolymers synthesized by microorganisms such as the bacterium Burkholderia xenovorans LB400. In particular, LB400 cells are capable to synthesize poly(3-hydroxybutyrate) (PHB) from glucose. The aim of this study was to produce and characterize electrospun fibers obtained from bacterial PHBs. Bacterial strain LB400 was grown in M9 minimal medium using xylose and mannitol (10 g L −1 ) as the sole carbon sources and NH 4 Cl (1 g L −1 ) as the sole nitrogen source. Biopolymer-based films obtained were used to produce fibers by electrospinning. Diameter and morphology of the microfibers were analyzed by scanning electron microscopy (SEM) and their thermogravimetric properties were investigated. Bead-free fibers using both PHBs were obtained with diameters of less than 3 μm. The surface morphology of the microfibers based on PHBs obtained from both carbon sources was different, even though their thermogravimetric properties are similar. The results indicate that the carbon source may determine the fiber structure and properties. Further studies should be performed to analyze the physicochemical and mechanical properties of these PHB-based microfibers, which may open up novel applications. [ABSTRACT FROM AUTHOR]

Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis. Ulmo honey volatiles consisted of 50 compounds predominated by 20 flavor components. Two of the volatile compounds, lyrame and anethol have never been reported before as honey compounds. The non-volatile/semi-volatile components of Ulmo honey comprised 27 compounds including 13 benzene derivatives accounting 75% of the total peak area. Ulmo honey exhibited weak antioxidant activity but strong antibacterial activity particularly against gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), the main strain involved in wounds and skin infections. At concentrations > 0.5%, Ulmo honey reduced Caco-2 cell viability, released lactate dehydrogenase (LDH) and increased reactive oxygen species (ROS) production in a dose dependent manner in the presence of foetal bovine serum (FBS). The wide array of volatile and non-volatile/semi-volatile constituents of Ulmo honey rich in benzene derivatives may partly account for its strong antibacterial and antiproliferative properties important for its therapeutic use. Our results indicate that Ulmo honey can potentially inhibit cancer growth at least partly by modulating oxidative stress. [ABSTRACT FROM AUTHOR]

FLOR1 is a flower-specific leucine-rich repeat (LRR) protein that interacts in vitro with the MADS box protein AGAMOUS. However, FLOR1 belongs to the plant-specific (PS) subfamily of LRR proteins which are thought to be extracellular based on immunolocalization experiments with one of them and the presence of a hydrophobic signal peptide in the N-terminus of all of them. As a first step towards exploring the possible in vivo role of the AG–FLOR1 interaction, we show here that FLOR1 mRNA in wild type Arabidopsis thaliana is specific to inflorescence meristems, floral meristems, stamens and carpels with a spatio-temporal mRNA expression pattern during flower development that is similar to that of AGAMOUS. To confirm FLOR1 transcription expression in meristems, stamens and carpels, its mRNA pattern of expression was studied in mutants of floral meristem or floral organ identity genes (LEAFY, APETALA1, CAULIFLOWER, AGL8, APETALA2, and APETALA3). Furthermore, immunolocalization experiments show that the FLOR1 transcript and protein have similar expression patterns. Light and electron micrographs of immunolocalization experiments, as well as GFP cellular localization in transgenic A. thaliana lines expressing FLOR1-GFP chimeric proteins suggest that FLOR1 is localized in the cytoplasm and nucleus inside cells. These results contrast with previous reports that suggest that other members of the same PS LRR subfamily are only localized in the extracellular space. The functional relevance of our findings in terms of the possible in vivo interaction of FLOR1 and AGAMOUS are discussed. [Copyright &y& Elsevier]

Carotenoid (astaxanthin or lycopene) emulsions obtained by high pressure homogenization were investigated for their physical, oxidative and storage stability and biological fate on an in vitro digestion model of bioaccessibility. Emulsion stability evaluated at various processing environments (20–50 °C, 2–10 pH, 0–500 mM NaCl, and 0–35 days storage at 25 °C) depended on carotenoid and homogenization pressures (5, 10, 100 MPa). Trolox increased the oxidative stability of nanoemulsions (100 MPa) and acted synergistically with BHT in increasing the stability of lycopene nanoemulsion. Intestinal digestibility depended on homogenization pressures with the fastest release and lower amount of free fatty acids observed at 100 MPa. Carotenoid nanoemulsions (100 MPa) were partially (66%) digested and highly bioaccessible (>70%). Therefore, nanoemulsions provide an effective and stable system for efficient astaxanthin or lycopene delivery and bioavailability in foods, beverages, nutraceuticals and/or other agriproducts. [ABSTRACT FROM AUTHOR]

Poly-3-hydroxybutyrate (PHB) is a biocompatible polymer produced by a wide variety of bacteria from different carbon sources. However, the carbon source effects on PHB properties are largely unknown. This study aimed to characterize PHB produced by Paraburkholderia xenovorans LB400 supplied with glucose (PHB g), mannitol (PHB m), or xylose (PHB x) as sole carbon sources and to evaluate their potential application as the main component of scaffolds obtained by electrospinning. The PHBs produced by strain LB400 had different molecular weights; the largest value corresponded to PHB m. The XRD-spectra revealed that PHB produced by strain LB400 from the three carbon sources are less crystalline than the commercially available polymer (PHB c). Moreover, the electrospinning process decreases even further their degree of crystallinity, which could lead to an improvement in the mechanical properties of the polymers. Relevantly, PHB x -microfibers exhibited mechanical characteristics similar to those of human skin. None of the scaffolds made of PHBs from strain LB400 grown in different carbon sources showed adverse effects on fibroblast cell growth. Thus, modifying the sugar used as the carbon source may be useful to tune the structural properties of PHB and its performance as a component of electrospun scaffolds, which may better fit specific biomedical applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the potential of the alginate/shellac combination as wall material (WM) to develop an oil encapsulation system by external gelation. The Taguchi method, a powerful process optimization tool, was used to determine the optimal process conditions in which to prepare beads with a high oil encapsulation efficiency (EE). The effect of the variables: sunflower oil concentration in the emulsion (E [oil] : 30 and 50 %w/w), emulsion/wall material ratio (E/WM: 80/20 and 20/80 %v/v) and concentration of calcium chloride (CaCl 2 : 5 and 15 g/L) on the EE were evaluated. The bead morphology, the total oil content of beads (OCB), mean particle size, sphericity factor (SF) and swelling degree (Sw) were also investigated. Finally, the optimal alginate/shellac beads were submitted to in vitro digestion. The results showed that the beads formed under optimal conditions reached an EE value of 98.7% and OCB of 38.6%. The oil concentration in the emulsion was the variable that most affected the oil EE. The beads obtained were semi-spherical, smooth-surfaced, non-aggregated, with a particle size of 2.13 mm and SF of 0.08. The Sw of the developed alginate/shellac beads was unaffected at acid pH values; however, beads showed swelling under basic conditions (pH 7). The optimal beads showed more oil released during intestinal digestion than during gastric digestion. These findings have important implications for oil encapsulation and the design of delivery systems of oil soluble compounds, which are useful in the food industry for developing novel products containing health-promoting bioactive compounds. [ABSTRACT FROM AUTHOR]

Encapsulation of linseed oil into high oil content alginate beads has appeared as a potential solution to delay oxidation of this highly unsaturated oil. Additionally, the use of vegetable protein as emulsifier is used in order to enhance the stability of the emulsion and thus the encapsulation efficiency (EE). The aim of this work was to optimize the emulsion formulation in order to maximize EE in dried beads. The effect of alginate (X 1 : 10–45 g/L) and lupin protein concentrations (X 2 : 10–50 g/L) in the aqueous phase and oil/water ratio (X 3 : 15–60 mL/100 mL) on EE, as well as on the oil content, was evaluated by a central composite experimental design (2 3 ). The mathematical model showed a great dependence of the studied variables and EE, demonstrating that high alginate and protein concentrations were desirable. By using the optimal formulation, spherical beads of approximately 1.80 mm were obtained. Actual EE (98.30%) for optimal oven dried beads was found to be close to the predicted value (100.88%). Moreover, the optimal beads contained 66.37% of linseed oil, being the most successfully delivered in in vitro digestive conditions. The stability of encapsulated oil against heat treatments (50–75 °C, 24 h) was higher than free linseed oil, demonstrating the effectiveness of the encapsulating system. Based on the results obtained, the encapsulating system used in this study is suitable for unstable oils for food or nutraceutical purposes. [ABSTRACT FROM AUTHOR]