Antioxidant activities of Melittis melissophyllum L. (Lamiaceae)

Extracts of Melittis melissophyllum leaves in ether, chloroform, ethyl acetate, n-butanol and water were evaporated to dryness and dissolved in 50% ethanol to make 10% (w/v) solutions. The potential protective action of the extracts was assessed by the corresponding in vitro and in vivo tests. In the in vitro experiments extracts were tested as potential scavengers of free radicals (DPPH, O?·?, NO, and OH radicals), as well as inhibitors of liposomal peroxidation (LPx). The results obtained show that all extracts (exept n-BuOH extract) are good scavengers of radicals and reduce LPx intensity in liposomes, which points to their protective (antioxidant) activity. In vivo experiments were concerned with antioxidant systems (activities of GSHPx, GSHR, Px, CAT, XOD, GSH content and intensity of LPx) in liver homogenate and blood-hemolysate of experimental animals after their treatment with extracts of M. melissophyllum leaves, or in combination with CCl?. On the basis of the results obtained it can be concluded that the examined extracts have protective (antioxidative) effect and this antioxidative behaviour is more pronounced in liver than in blood-hemolysate. The reason is probably the fact that liver contains other enzymatic systems, which can also participate in the antioxidative mechanism. Of all the extracts the H?O one showed the highest protective activity.     

Lichtheimia blakesleeana as a new potencial producer of phytase and xylanase

Brazil is known for its great potential for production of renewable resources such as agro-industrial residues. These residues can be used as alternative sources of new products. Meanwhile, solid-state fermentation, with its advantages of energy conservation and pollution reduction, has been identified as a process of great potential for the production of bioactive compounds, especially enzymes. In the present work, a 2(3) factorial design was used to evaluate the effects of pH, temperature and moisture on the production of phytase and xylanase by Lichtheimia blakesleeana URM 5604 through the fermentation of citrus pulp. Statistical analyses of the results showed that the only the pH influenced the production of these enzymes, with the best phytase production (264.68 U/g) ocurring at pH 6.0, 34 °C, initial moisture 50%, after 48 hours of culture. The best conditions for xylanase production (397.82 U/g) were fermentation for 120 hours at pH 4.0, 26 °C and initial moisture of 70%. The best parameters for the simultaneous production of phytase (226.92 U/g) and xylanase (215.59 U/g) were determined to be initial moisture of 50%, pH 6.0, 26 °C, and 48 hours of fermentation.     

Bistable coupling states measured on single Co nanoclusters deposited on CoO(111)

We describe novel features of the induced magnetic anisotropy in Co nanoclusters coupled with a CoO(111) layer. Individual cluster magnetism was studied using new microbridge superconducting quantum interference devices. Intrinsically, the Co clusters are single domains with an effective anisotropy constant K(F)≈1.5×10(6) erg·cm(-3). A bistable state of the ferromagnetic-antiferromagnetic coupling is revealed, with a maximum bias systematically observed along CoO[10 ?1] and an interfacial coupling energy of 0.9 erg·cm(-2). The small bias observed in cluster assembly results from an averaging over the two opposite stable states.     

Resveratrol in Solid Lipid Nanoparticles

This article investigates the possibility of producing solid lipid nanoparticles (SLN) as protective vehicle of resveratrol, an antioxidant characterized by a fast trans-cis isomerization. SLN aqueous dispersions were produced by hot melt homogenization technique and characterized. It was found that the presence of tetradecyl-γ-cyclodextrin in SLN formulation induced an improvement of nanoparticle characteristics. Moreover, a significant reduction in resveratrol photodegradation was noted when the molecule was entrapped in SLN which became more pronounced in the presence of tetradecyl-γ-cyclodextrin. A notable in vitro porcine skin accumulation and an increased antioxidative efficacy were observed by entrapping resveratrol in nanoparticles.     

BEHAVIOUR OF OIL/WATER MICROEMULSIONS UPON DILUTION WITH WATER

The dilution of series of oil-in-water microemulsions, formulated with Aerosol-OT as surfactant, water, isopropyl myristate as oil and varying amounts of butanol as cosurfactant, was studied. An infinite dilution could be obtained only adding water containing surfactant; the minimum amount of Aerosol-OT required was determined. The behaviour of the microemulsions upon dilution was related to the presence of nixed micelles in the aqueous phase.     

Study on pesticide residues in apples,apple-based baby food,and their behaviour during processing using fast GC–MS multiresidue analysis

Food-processing experiments using apples were conducted to obtain more knowledge on the behaviour of pesticides during apple-based baby-food production. The residues were determined in raw material (apples), in intermediate products at different steps of the processing procedure (baby food production) and in final products (apple purée) using a rapid GC–MS method in combination with two different sample-preparation approaches. During 2 years of a monitoring programme, 84 analyses of apple samples and 102 of baby food sample apple purée intermediate and final product samples from baby food production were performed. A pesticide-residue search revealed that residues in fresh apples do not exceed the maximum residue limit for the adult population, but there were some positive findings concerning apples as baby food. The maximal pesticide concentration (fluquinconazole) found in apples was 0.099?mg?kg^?1. In the processed apple-based baby food the concentration of pesticide residues were mostly below 0.010?mg?kg^?1.     

Photochemical and antioxidant properties of gamma-oryzanol in beta-cyclodextrin-based nanosponges

Gamma-oryzanol (GO), a mixture of ferulic acid esters, has recently attracted a great interest as natural antioxidant extracted from rice-bran oil, usually employed to stabilize food and pharmaceutical raw materials, moreover as sunscreen in cosmetic formulations. Its usefulness, however, is limited by its fast degradation. A recently proposed approach to increase the stability and effectiveness of antioxidants is based on the inclusion in supramolecular structures (nanoparticles, cyclodextrins, liposomes, etc.). In this work we studied the inclusion of GO in β-cyclodextrin-based nanosponges which in the last few years have been chosen for their ability to encapsulate a great variety of substances to decrease their side-effects and to protect them from degradation. The inclusion complex was prepared in 1:1 w/w ratio and characterized by DSC, XRPD and membrane diffusion runs. The photodegradation of GO upon either UVA or UVB irradiation was found to be slowed down by inclusion in nanosponges. The antioxidant effectiveness of the inclusion complex was also assessed and in vitro experiments on porcine ear skin revealed a certain accumulation of GO also when entrapped in the host structure.     

Thermodynamics of the Complexation of the p-Sulfonatocalix[4]arene with Simple Model Guests in Water: a Microcalorimetric Study

The formation of supramolecular complexes in water involves interactions of various types which are not always easy to identify, especially when complicated species are involved. A complete thermodynamic characterization of the binding process, which includes the enthalpies and entropies of complexation, is obviously one of the key elements in identifying the stabilizing factors and in understanding how the host and guest assemble. In order to thermodynamically characterize typical interactions of various types, we have thus undertaken a microcalorimetric study of the complexation of p-sulfonatocalixarenes with simple guests bearing different functional groups. Association constants, free energies, enthalpies and entropies for the complexation of the p-sulfonatocalix[4]arene with normal alcohols, alkylammonium, carboxylate and guanidinium ions in water, at pH 7.5 and 298.15?K, are reported. The properties for the binding of lysine and arginine, which bear similar functional groups, are also given. The comparison of the thermodynamic behaviour of these different guests allows the driving factors to be identified. This may constitute a starting point for the understanding of the recognition of more complicated guests.     

In Vitro Antimicrobial Activity of Lavender,Mint, and Rosemary Essential Oils and the Effect of Their Vapours on Growth of Penicillium spp. in a Bread Model System

The chemical composition, antioxidant activity, and antimicrobial properties of three commercially available essential oils: rosemary (REO), lavender (LEO), and mint (MEO), were determined in the current study. Our data revealed that the major components of REO, MEO, and LEO were 1,8-cineole (40.4%), menthol (40.1%), and linalool acetate (35.0%), respectively. The highest DPPH radical-scavenging activity was identified in MEO (36.85 ± 0.49%) among the investigated EOs. Regarding antimicrobial activities, we found that LEO had the strongest inhibitory efficiencies against the growth of Pseudomonas aeruginosa and Candida (C.) tropicalis, MEO against Salmonella (S.) enterica, and REO against Staphylococcus (S.) aureus. The strongest antifungal activity was displayed by mint EO, which totally inhibited the growth of Penicillium (P.) expansum and P. crustosum in all concentrations; the growth of P. citrinum was completely suppressed only by the lowest MEO concentration. The lowest minimal inhibitory concentrations (MICs) against S. enterica, S. aureus, and C. krusei were assessed for MEO. In situ analysis on the bread model showed that 125 µL/L of REO exhibited the lowest mycelial growth inhibition (MGI) of P. citrinum, and 500 µL/L of MEO caused the highest MGI of P. crustosum. Our results allow us to make conclusion that the analysed EOs have promising potential for use as innovative agents in the storage of bakery products in order to extend their shelf-life.     

A new semilocal convergence theorem for the Weierstrass method for finding zeros of a polynomial simultaneously

In this paper we study the convergence of the famous Weierstrass method for simultaneous approximation of polynomial zeros over a complete normed field. We present a new semilocal convergence theorem for the Weierstrass method under a new type of initial conditions. Our result is obtained by combining ideas of Weierstrass (1891) and Proinov (2010). A priori and a posteriori error estimates are also provided under the new initial conditions.