Phosphodiester Hydrogels for Cell Scaffolding and Drug Release Applications

Given the major structural role phosphodiesters play in the organism it is surprising they have not been more widely adopted as a building block in sophisticated biomimetic hydrogels and other biomaterials. The potential benefits are substantial: phosphoester‐based materials show excellent compatibility with blood, cells, and a remarkable resistance to protein adsorption that may trigger a foreign‐body response. In this work, a novel class of phosphodiester‐based ionic hydrogels is presented which are crosslinked via a phosphodiester moiety. The material shows good compatibility with blood, supports the growth and proliferation of tissue and presents opportunities for use as a drug release matrix as shown with fluorescent model compounds. The final gel is produced via base‐induced elimination from a phosphotriester precursor, which is made by the free‐radical polymerization of a phosphotriester crosslinker. This crosslinker is easily synthesized via multigram one‐pot procedures out of common laboratory chemicals. Via the addition of various comonomers the properties of the final gel may be tuned leading to a wide range of novel applications for this exciting class of materials.     

Principal Components – Based Techniques in Voltammetric Determination of Caffeic,Syringic and Vanillic Acids

It was demonstrated that Principal Components Analysis and Principal Components Regression support qualitative and quantitative investigation of three‐component synthetic samples containing micromolar concentration of caffeic acid (CA), syringic acid (SA) and vanillic acid (VA), in various proportions. The first, second and third PCs enable modelling of relationships and distinction of objects of different composition. Optimized and validated multivariate calibration models, implemented on the basis of the samples selected with the help of 3‐level full factorial design, effectively support simultaneous determination of the considered analytes. Obtained RMSEP was no higher than 0.23 μm for CA, 0.17 μm for SA and 0.21 μm for VA, in relation to the concentration of 1.9 to 21.4 μm of each compound. Recovery between 90–108% for considered analytes, determined in synthetic wine solution, was additional verification of calibration model. Application of automatic baseline correction was extensively studied.     

Synthesis,spectroscopic studies,and crystal structure of 2,6-diacetylpyridinediphenylhydrazone perchlorate and its complexing ability toward the lanthanides

2,6-diacetylpyridinediphenylhydrazone perchlorate was prepared and characterized by spectroscopic (IR, ESI–MS, UV–Vis, ¹H NMR) and analytical data and its crystal structure was determined by single X-ray analysis. The lanthanum(III), praseodymium(III), and neodymium(III) perchlorate complexes of 2,6-diacetylpyridinediphenylhydrazone were prepared in a direct reaction of the ligand with appropriate metal perchlorates. The spectroscopic and analytical data indicate 1:2 metal to ligand stoichiometry. In all the complexes the hydrazones act as monodeprotonated terdentate NNN donor chelators. The same lanthanum(III) complex was also obtained in a one-step condensation reaction between 2,6-diacetylpyridine and phenylhydrazine in the presence of lanthanum(III) perchlorate.     

Anti-Cancer Potential of Synthetic Oleanolic Acid Derivatives and Their Conjugates with NSAIDs

Naturally occurring pentacyclic triterpenoid oleanolic acid (OA) serves as a good scaffold for additional modifications to achieve synthetic derivatives. Therefore, a large number of triterpenoids have been synthetically modified in order to increase their bioactivity and their protective or therapeutic effects. Moreover, attempts were performed to conjugate synthetic triterpenoids with non-steroidal anti-inflammatory drugs (NSAIDs) or other functional groups. Among hundreds of synthesized triterpenoids, still the most promising is 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), which reached clinical trials level of investigations. The new group of synthetic triterpenoids are OA oximes. The most active among them is 3-hydroxyiminoolean-12-en-28-oic acid morpholide, which additionally improves the anti-cancer activity of standard NSAIDs. While targeting the Nrf2 and NF-κB signaling pathways is the main mechanism of synthetic OA derivatives′ anti-inflammatory and anti-cancer activity, most of these compounds exhibit multifunctional activity, and affect cross-talk within the cellular signaling network. This short review updates the earlier data and describes the new OA derivatives and their conjugates in the context of modification of signaling pathways involved in inflammation and cell survival and subsequently in cancer development.     

Untersuchung von Bier

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Antimicrobial activity of new bicyclic lactones with three or four methyl groups obtained both synthetically and biosynthetically

Ten new derivatives of isophorone were obtained through a five-step synthesis. Among the products were several unsaturated, bicyclic lactones with three or four methyl groups. These lactones were used as the substrates for biotransformation mediated by selected fungal strains (Fusarium species, Syncephalastrum racemosum, Cunninghamella japonica, Penicillium species, Absidia species, and Pleurotus ostreatus). Four new hydroxylactones were obtained as a result of biotransformation. Because the unsaturated lactone with four methyl groups was a diastereoisomeric mixture, a structural analysis was conducted. The hydroxylactones were also included in this analysis. Both the unsaturated lactones and hydroxylactones were examined for their antimicrobial activity. It was found that some of these compounds exhibited growth inhibition against pathogenic strains of bacteria (Staphylococcus aureus, Pseudomonas fluorescens), yeasts (Candida albicans) and filamentous fungi (Alternaria sp., Penicillium sp.). All obtained compounds were also subjected to scent analysis.     

Ruthenium,rhodium and palladium complexes of pyridines

Summary The syntheses, chemical reactivity, physicochemical properties and applications in solar energy conversion and storage of ruthenium, rhodium and palladium complexes of pyridines are described.     

Cadaverinium dichloride: a case of centro–non‐centrosymmetric ambiguity

In the title salt, also known as pentane‐1,5‐diammonium dichloride, C₅H₁₆N₂²⁺·2Cl⁻, the cation exists in an ideal fully extended conformation and lies on a mirror plane in the space group Pbam. In the crystal structure, layers of cations are hydrogen bonded with Cl⁻ anions, which occupy the space between the layers. This kind of packing leads to a short unit‐cell parameter of 4.463 (1) Å. This structure is another case of centro–non‐centrosymmetric ambiguity; the best results were obtained in a centrosymmetric space group, with the disordered NH₃ groups accounting for the non‐centrosymmetric `component'.