The antioxidant activity ofwater, ethanol and methanol Hieracium pilosella L.extracts is reported. The antioxidative activity was tested by spectrophotometrically measuring their ability to scavenge a stable DPPH^· free radical and a reactive hydroxyl radical trapped by DMPO during the Fenton reaction, using the ESR spectroscopy. Total phenolic content and total flavonoid content were evaluated according to the Folin-Ciocalteu procedure, and a colorimetric method, respectively. A HPLC method was used for identification of some phenolic compounds (chlorogenic acid, apigenin-7-O-glucoside and umbelliferone). The antioxidant activity of the investigated extracts slightly differs depending on the solvent used. The concentration of 0.30 mg/mL of water, ethanol and methanol extract is less effective in scavenging hydroxyl radicals (56.35, 58.73 and 54.35%, respectively) in comparison with the DPPH^· radical scavenging activity (around 95% for all extracts). The high contents of total phenolic compounds (239.59–244.16 mg GAE/g of dry extract) and total flavonoids (79.13–82.18 mg RE/g of dry extract) indicated that these compounds contribute to the antioxidative activity.

Earth smoke herb (Fumaria officinalis L.) was used as a source of extractive mat­ter in this study. The aqueous extract was obtained by pouring boiling water over the plant material (1:20 m/v) and letting it stay for 90 minutes at room temperature. The identification of bioactive compounds in the extract was performed using the UHPLC-DAD-ESI-MS analysis. The content of total phenols and total flavonoids was determined spectrophotometrically by Folin-Ciocalteu and AlCl3 methods, respectively. The antioxidant activity of the extract was also investigated spectropho­tometrically by DPPH and ABTS assays. A discdiffusion method was used in the antimicrobial activity investigation on the following pathogenic microorganisms: Candida albicans, Proteus vulgaris, Pseudomonas aeruginosa, Bacillus subtilis, Staphy­lococcus aureus, Escherichia coli and Klebsiella pneumoniae. Seven components were detected in the obtained extract, while caffeic and rosmarinic acid were identified. The main component in the extract was rosmarinic acid (16.7 g/100 g of dry extract). The content of total phenols was 77.67 mg GAE/g of the dry extract while the content of total flavonoids was 21.21 mg RE/g of the dry extract. The extract concentrations required to neutralize 50% of the initial DPPH radical concentration were 7.38 and 8.18 μg/cm3 after 30 and 20 min of incubation, respectively, as well as 48.6 μg/cm3 with no incubation. The extract concentration required to neutralize 50% of the initial ABTS radical concentration was 96.0 μg/cm3. The obtained extract has shown the highest antimicrobial activity against Candida albicans fungus. The presented results indicate that the aqueous earth smoke extract should be rightly considered as a potential source of natural antioxidants and antimicrobial agents.

This paper aimed to estimate the influence of peppermint (Mentha × piperita L.) leaves grinding on the essential oil (PEO) yield, composition, antibacterial and antifungal activities. Besides positively affecting the yield, grinding provided PEO with 44 compounds, compared to 33 compounds isolated from non-ground leaves. The most abundant compounds in both PEOs were menthol and menthone. PEO isolated from the ground leaves expressed higher antibacterial and antifungal activities , with S. aureus and C. albicans being the most susceptible microorganisms. According to these results, PEO from ground leaves has the potential to be used in food industry and packaging, production of nutraceuticals, natural pharmaceuticals and cosmetics.

Polyrotaxanes are intermediary products in the synthesis of topological gels. They are created by inclusion complex formation of hydrophobic linear macromolecules with cyclodextrins or their derivatives. Then, pairs of cyclodextrin molecules with covalently linkage were practically forming the nodes of the semi-flexible polymer network. Such gels are called topological gels and they can absorb huge quantities of water due to the net flexibility allowing the poly(ethylene oxide) chains to slide through the cyclodextrin cavities, without being pulled out altogether. For polyrotaxane formation poly(ethylene oxide) was used like linear macromolecules. There are hydroxyl groups at poly(ethylene oxide) chains, whereby the linking of the voluminous molecules should be made. To avoid the reaction of cyclodextrin OH groups with stoppers, they should be protected by, e.g., acetylation. In this work, the acetylation of the OH groups of β-cyclodextrin was performed by acetic acid anhydride with iodine as the catalyst. The acetylation reaction was assessed by the FTIR and HPLC method. By the HPLC analysis was found that the acetylation was completed in 20 minutes. Inserting of poly(ethylene oxide) with 4000 g/mol molecule mass into acetyl-β-cyclodextrin with 2:1 poly(ethylene oxide) monomer unit to acetyl-β-cyclodextrin ratio was also monitored by FTIR, and it was found that the process was completed in 12 h at the temperature of 10°C. If the process is performed at temperatures above 10°C, or for periods longer than 12 hours, the process of uncontrolled hydrolysis of acetate groups was initiated.

As the mechanical properties of resin-based dental composite materials are highly relevant in clinical practice, diverse strategies for their potential enhancement have been proposed in the extant literature, aiming to facilitate their reliable use in dental medicine. In this context, the focus is primarily given to the mechanical properties with the greatest influence on clinical success, i.e., the longevity of the filling in the patient’s mouth and its ability to withstand very strong masticatory forces. Guided by these objectives, the goal of the present study was to ascertain whether the reinforcement of dental composite resins with electrospun polyamide (PA) nanofibers would improve the mechanical strength of dental restoration materials. For this purpose, light-cure dental composite resins were interspersed with one and two layers comprising PA nanofibers in order to investigate the influence of such reinforcement on the mechanical properties of the resulting hybrid resins. One set of the obtained samples was investigated as prepared, while another set was immersed in artificial saliva for 14 days and was subsequently subjected to the same set of analyses, namely Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Findings yielded by the FTIR analysis confirmed the structure of the produced dental composite resin material. They also provided evidence that, while the presence of PA nanofibers did not influence the curing process, it strengthened the dental composite resin. Moreover, flexural strength measurements revealed that the inclusion of a 16 μm-thick PA nanolayer enabled the dental composite resin to withstand a load of 3.2 MPa. These findings were supported by the SEM results, which further indicated that immersing the resin in saline solution resulted in a more compact composite material structure. Finally, DSC results indicated that as-prepared as well as saline-treated reinforced samples had a lower glass transition temperature (Tg) compared to pure resin. Specifically, while pure resin had a Tg of 61.6 °C, each additional PA nanolayer decreased the Tg by about 2 °C, while the further reduction was obtained when samples were immersed in saline for 14 days. These results show that electrospinning is a facile method for producing different nanofibers that can be incorporated into resin-based dental composite materials to modify their mechanical properties. Moreover, while their inclusion strengthens the resin-based dental composite materials, it does not affect the course and outcome of the polymerization reaction, which is an important factor for their use in clinical practice.