Elucidating the antibiofilm activity of Frangula emodin against Staphylococcus aureus biofilms

Aims Because the Staphylococcus aureus is one of the most well‐known pathogens associated with medical devices and nosocomial infections, the aim of the study was to examine antibiofilm potential of emodin against it. Methods and Results Antibacterial activity was examined through microdilution assay. Antibiofilm testing included crystal violet staining of biofilm biomass and morphology analysis by Atomic force microscopy (AFM). Furthermore, aerobic respiration was monitored using the Micro‐Oxymax respirometer. For investigation of gene expression qRT‐PCR was performed. Emodin demonstrated strong antibacterial activity and ability to inhibit biofilm formation of all tested strains. The effect on preformed biofilms was spotted in few strains. AFM revealed that emodin affects biofilm structure and roughness. Monitoring of respiration under emodin treatment in planktonic and biofilm form revealed that emodin influenced aerobic respiration. Moreover, qRT‐PCR showed that emodin modulates expression of icaA, icaD, srrA and srrB genes, as well as RNAIII, and that this activity was strain‐specific. Conclusion The results obtained in this study indicate the novel antibiofilm activity of emodin and its multiple pathways of action. Significance and Impact of Study This is the first study that examined pathways through which emodin expressed its antibiofilm activit

Curcumin loaded pegylated nanoemulsions designed for maintained antioxidant effects and improved bioavailability: A pilot study on rats

The current study describes the experimental design guided development of PEGylated nanoemulsions as parenteral delivery systems for curcumin, a powerful antioxidant, as well as the evaluation of their physicochemical characteristics and antioxidant activity during the two years of storage. Experimental design setup helped development of nanoemulsion templates with critical quality attributes in line with parenteral application route. Curcumin-loaded nanoemulsions showed mean droplet size about 105 nm, polydispersity index <0.15, zeta potential of −40 mV, and acceptable osmolality of about 550 mOsm/kg. After two years of storage at room temperature, all formulations remained stable. Moreover, antioxidant activity remained intact, as demonstrated by DPPH (IC50 values 0.078–0.075 mg/mL after two years) and FRAPS assays. In vitro release testing proved that PEGylated phospholipids slowed down the curcumin release from nanoemulsions. The nanoemulsion carrier has been proven safe by the MTT test conducted with MRC-5 cell line, and effective on LS cell line. Results from the pharmacokinetic pilot study implied the PEGylated nanoemulsions improved plasma residence of curcumin 20 min after intravenous administration, compared to the non-PEGylated nanoemulsion (two-fold higher) or curcumin solution (three-fold higher). Overall, conclusion suggests that developed PEGylated nanoemulsions present an acceptable delivery system for parenteral administration of curcumin, being effective in preserving its stability and antioxidant capacity at the level highly comparable to the initial findings

Geochemical distribution of selected elements in flotation tailings and soils/sediments from the dam spill at the abandoned antimony mine Stolice, Serbia

Materials held within mine tailings pose a serious risk to the environment in cases of tailings dam failure. Collapse of the tailing dam at the Stolice antimony mine in West Serbia caused a spilling of tailing slurry into the nearby river watersheds. Medium-term effects of As, Pb, Sb, Zn, and Cd from the tailings material that remained in the flooded zone 3 years after the initial exposure were evaluated. Mobility of these elements was determined by analyzing their distribution between exchangeable, reducible, oxidizable, and residual phases. Results indicate that Fe-Mn oxides represent important sinks for As, Cd, Pb, and Sb. Multivariate statistical analysis revealed that concentrations of the analyzed elements were related to sand-sized fractions, as they tended to adsorb or co-precipitate as coatings on larger particles (particularly feldspar and quartz) upon the change of redox conditions. Assessment of the most relevant physico-chemical factors, metal(loid) concentration, and mobility can be used as tool to characterize the degree of contamination of impacted sites. Percentage of sand-sized particles, content of investigated metal(loid)s, and their amount in the reducible fractions are factors determining the best remediation techniques for the area impacted by tailing spill

Discovery of anxiolytic 2-ferrocenyl-1,3-thiazolidin-4-ones exerting GABA(A) receptor interaction via the benzodiazepine-binding site

Herein, we report on the synthesis, spectral, crystallographic and electrochemical properties of a small library of N-substituted 2-ferrocenyl-1,3-thiazolidin-4-ones, designed as novel GABA(A) benzodiazepine-binding site ligands. The anxiolytic properties of the title compounds were evaluated in several different in vivo models, whereas the involvement of the GABAA receptor complex in the activity of the most potent compound, 2-ferrocenyl-3-(4-methoxyphenylethyl)-1,3-thiazolidin-4-one, was inferred from experiments with known GABA(A)-targeting agents. Ligand docking experiments revealed that the high, dose-dependent, anxiolytic activity of the new compounds might be due to their favorable interactions with the benzodiazepine-binding site of the GABA(A) receptor complex. The incorporation of the ferrocene core and fine tuning of the distance between the thiazolidinone core and an additional aromatic ring were judged to be crucial structural requirements for the observed anxiolytic effect. (C) 2014 Elsevier Masson SAS. All rights reserved