Search

Drugs remain for a short time on mucus membranes, such as oral, ocular, or nasal mucus, which are washed with physiological fluids. One of the possibilities to overcome this obstacle is the application of solutions that, due to the physiological environment or stimulus, turn into more viscous gels. These gels often also have mucoadhesive properties and the drug is released from them for a longer period. Carbomer 940 (C940), polycarbophil (PCP), and chitosan (CH) are gel-forming excipients, and the consistency of their solutions changes due to the concentration of protons (pH); therefore, they are referred to as pH-sensitive gelling agents. The aim of this study was to prepare pH-sensitive solutions that form gels in the pH of the oral cavity. We prepared water solutions with various concentrations of gel-forming excipients and evaluated the appearance, pH of the solution, injectability of the solution, and pH of gelation. By determining the pH of gelation, suitable concentrations (w/w) of the used polymers were found, namely, 0.1% C940, 0.225% PCP, and 2.5% CH with medium molecular weight (CHM). The 0.1% C940 and 0.225% PCP solutions were injectable through the syringe with the smallest 0.5 mm needle diameter. The 2.5% CHM solution was not injectable even through the syringe with the largest 0.8 mm needle diameter. Solgels prepared at the determined concentrations were evaluated by a dissolution test in a pH 6.8 phosphate buffer using methylene blue (MB) as a model substance. After 60 min of dissolution, 77.04% ± 5.94%, 48.85% ± 5.74%, and 77.35% ± 4.98% of MB were released from samples with C940, PCP, and CHM, respectively. The dissolution of the C940 and CHM samples took place according to the Korsmeyer–Peppas kinetic model (R2 0.999 ± 0.001, 0.978 ± 0.003) and of the PCP samples took place according to the first-order model (R2 0.994 ± 0.001). The 0.225% PCP pH-sensitive gel showed the most advantageous properties in terms of injectability, pH gelation, and prolonged release of MB.

Elemental composition of Vaccinium myrtillus L. and Vaccinium vitis-idaea L. has not been determined yet in detail. In our study, a scanning electron microscope coupled with an energy dispersive X-ray analyser (SEM-EDX) ensured the determination of 15 elements in the leaves of Vaccinium sp. growing in the control and the mine polluted locality. The soil elemental analyses showed a higher content of 11 elements from all determined in the mine-influenced samples. Elemental analyses of the control leaves showed the highest contents of all determined elements for V. vitis-idaea, except for carbon. The impact of pollution on V. myrtillus leaves caused significant increase in oxygen, natrium, magnesium, sulphur, chlorine, potassium and calcium content. The contents of carbon, nitrogen and silicon decreased substantially. In the case of the V. vitis-idaea leaves, the content of most of elements reduced, and in the case of six elements, even significantly. A significant increase was recorded for carbon, iron and copper. The effect of the environment has influenced the production of phytochemicals, assessed by HPLC-DAD. The production of flavonoids (hyperoside, isoquercetin) increased significantly in V. myrtillus and decreased to a detectable minimum in V. vitis-idaea. In the case of chlorogenic acid, arbutin and hydroquinone, their levels changed minimally in V. myrtillus, but significantly more in the V. vitis-idaea leaves. The importance of elemental analyses lies in detecting the presence of toxic elements or their harmful concentrations in plants that are the source of food or dietary supplements., (© 2024. The Author(s).)

Natural products include a diverse set of compounds of drug discovery that are currently being actively used to target tumor angiogenesis. In the present study, we evaluated the anti-angiogenic activities of secondary metabolite usnic acid isolated from Usena antarctica. We investigated the in vitro effects on proliferation, migration, and tube formation of VEGF- and bFGF-stimulated HUVECs. Ex ovo anti-angiogenic activity was evaluated using the CAM assay. Our findings demonstrated that usnic acid in the concentration of 33.57 µM inhibited VEGF (25 ng/mL) and bFGF (30 ng/mL)-induced HUVECs proliferation, migration, and tube formation. The ex ovo CAM model was used to confirm the results obtained from in vitro studies. VEGF- and bFGF-induced vessel formation was inhibited by usnic acid after 72 h in over 2-fold higher concentrations compared to in vitro. Subsequently, histological sections of affected chorioallantoic membranes were stained with hematoxylin-eosin and alcian blue to determine the number and diameter of vessels as well as the thickness of the individual CAM layers (ectoderm, mesoderm, endoderm). Usnic acid was able to suppress the formation of VEGF- and bFGF-induced vessels with a diameter of less than 100 μm, which was demonstrated by the reduction of mesoderm thickness as well.

This study deals with the effect of zinc oxide nanoparticles (ZnO NPs) on halophyte from the genus Salicornia. The presence of ZnO nanoparticles (100 and 1000 mg/L) in the solid culture medium resulted in the negative effects on plant growth in the concentration-dependent manner. The shoot length of plant cultivated with 1000 mg/L ZnO NPs decreased by more than 50% compared to non-treated plants. The phytotoxicity was associated with the release of free zinc(II) ions, which was determined by atomic absorption spectroscopy and fluorescence microscopy. Another mechanism involved in ZnO NPs phytotoxicity was closely connected with generation of reactive oxygen species (ROS), which was accompanied by changes in activities and amounts of antioxidant enzymes. Histochemical evaluation showed that ROS were present also in the shoot of plant, which was not in direct contact with NPs. The reduction of activity and amount of antioxidant enzymes such as gamma-ESC, GR, SOD, PER, APX and higher concentration of ROS lead to lipid peroxidation, the latter being almost 3 times higher for the plant treated with 1000 mg/L NPs compared to control. The misbalance in zinc homeostasis and creation of ROS with subsequent oxidative stress led to the initiation of processes of programmed cell death, which was demonstrated by the loss of mitochondrial potential and increase of intracellular calcium (II) ions. Despite halophytes exhibit higher stress resistance than glycophytes, they are prone to negative changes if incubated in the environment containing ZnO nanoparticles., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

This study investigated the occurrence of toxicity, expressed as damage to the photosynthetic apparatus, in the aquatic fern Azolla filiculoides and the lichen Xanthoria parietina following treatments with diclofenac at different concentrations (0.1, 1, 10 and 100 mg/L) and different exposure times (24, 48, 72 and 240 h). Measurements of photosynthetic efficiency, chlorophyll content and chlorophyll degradation indicated dose- and time-dependent toxicity, since significant differences with control samples as well as among treatments, emerged mainly for the highest concentration (100 mg/L) and the longest time (240 h). In addition, also the mycobiont of the lichen X. parietina showed similar toxic effects, expressed as ergosterol content. The absence of relevant alterations at the lowest concentration (0.1 mg/L) suggested a very limited susceptibility of these species to environmentally relevant levels of this pharmaceutical.