No abstract

The aim of the study was to present chemical characteristics of a potential wood protection system composed of three chemical components. The paper presents preliminary results of chemical and biological analysis of wood treated with a mixture of 30% ethanol extract of propolis, caffeine and organosilanes: methyltrimetoxysilane (MTMOS) and octyltriethoxysilane (OTEOS). The sapwood of Scots pine (Pinus sylvestris L.) was impregnated with the above mentioned solution by vacuum method. The samples of wood treated with preservative were subjected to accelerated aging procedure according to EN 84 and subsequently to mycological tests according to the modified EN 113. Structural analysis of the treated wood was performed using infrared spectroscopy FTIR. The concentration of silicon in wood samples was determined by atomic absorption spectrometry AAS. The percentage content of nitrogen in wood samples was determined by elementary analysis EA. Slight differences in nitrogen and silicon content recorded in wood samples following impregnation and leaching confirm the permanent character of bonding between the propolis-silane-caffeine preparation and wood. The stable character of Si-C and Si-O bonds was shown in IR spectra and discussed in detail in this paper.

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe3+-reducing power, and ferrous ion (Fe2+)-chelating activity assays. The ability of the extracts to protect human red blood cell membranes against free-radical-induced damage and their antifungal activity was also determined. The results showed that the concentration of flavonoids in the propolis extracts was dependent on the solvent used in the extraction process and pinocembrin, chrysin, galangin, and coumaric acid were the most abundant phenols. All extracts exhibited high antioxidant potential and significantly protected human erythrocytes against oxidative damage. On the other hand, the antifungal activity of the propolis extracts depended on the solvent used in extraction and the fungal strains tested. It needs to be stressed that, to the best of our knowledge, there is no study relating the effect of solvent used for extraction of Polish propolis to its phenolic profile, and its antifungal, antioxidant, and cytoprotective activity.

Propolis is a natural material collected by honeybees, containing bioactive compounds that exhibit biological activity. The aim of this study was to assess the chemical composition of Polish propolis extracted with two different concentrations of ethanol, namely 70% and 96%, and to evaluate their antioxidant activity depending on extraction conditions. Samples of Polish propolis were extracted with 70% and 96% ethanol in order to obtain the ethanolic propolis extracts EEP70 and EEP96, respectively. Concentrations of 10 flavonoids and 6 phenolic acids were determined using the UPLC-PDA-TQD system. The antioxidant properties were determined based on the DPPH • free radical scavenging activity, Fe 3+ reducing power assay, and ferrous ions (Fe 2+) chelating activity assays. Moreover, the effects of the propolis extracts on human red blood cell morphology , the selective permeability of their membrane, as well as on free radicals-induced hemolysis were also assessed. Qualitative and quantitative analyses of both propolis extracts indicated that 70% ethanolic extract contained higher amounts of phenolic compounds than 96% ethanolic extract. The levels of antioxidant activity indicated that both Polish propolis extracts exhibited a high and comparable antioxidant power. The concentration of ethanol used for extraction had no effect on the antioxidant potential of propolis. The presented results indicate that the extracts of Polish propolis are rich in phenolic compounds and are very effective as antioxidant agents. Therefore, they may be applied as a constituent of products used in phytotherapy regardless of the concentration of ethanol used in propolis extraction.

The effects of ionizing radiation (electron beam) on poly(epsilon-caprolactone) (PCL) were studied by analyzing changes in viscosity-average and weight-average molecular weight and radius of gyration, and by performing sol-gel analysis and swelling tests. Samples were irradiated under various conditions: solid and molten PCL in the presence or absence of air. The overall efficiency of crosslinking is higher for samples irradiated in the molten state than in the solid state, and is reduced in the presence of oxygen. Based on three kinds of experiments (molecular weight dependence on the dose in the pre-gelation region, sol-gel analysis, and swelling study), radiation-chemical yields of intermolecular crosslinking and scission were determined and are discussed in terms of the mechanism of radiation-induced reactions in PCL. Properties of the gels formed by high-dose irradiation and mechanical properties of irradiated PCL were analyzed. Irradiation causes an increase in the compression modulus of PCL. This process occurs at the pre-gelation stage and continues in the gel-containing system. We have demonstrated, for the first time, that irradiation of solid PCL is accompanied by a pronounced post-effect, which manifests itself by changes in the average molecular weight. EPR data indicate that this effect, at least in part, is caused by the presence of long-lived radicals trapped in the crystalline regions. Irradiation with the sterilizing dose does not cause a statistically significant change in the biocompatibility of PCL after subsequent storage for 79 d, as determined by preliminary osteoblast vitality tests.