Zbigniew Rozwadowski

Spectroscopic studies of amino acid ionic liquid-supported Schiff bases.

Amino acid ionic liquid-supported Schiff bases, derivatives of salicylaldehyde and various amino acids (l-threonine, l-valine, l-leucine, l-isoleucine and l-histidine) have been investigated by means of various spectroscopic techniques (NMR, UV-Vis, IR, MS) and deuterium isotope effects on 13C-NMR chemical shifts. The results have shown that in all studied amino acid ionic liquid-supported Schiff bases (except the l-histidine derivative) a proton transfer equilibrium exists and the presence of the COO− group stabilizes the proton transferred NH-form.

Modification of Rapana thomasiana hemocyanin with choline amino acid salts significantly enhances its antiproliferative activity against MCF-7 human breast cancer cells

This is the first study on the interactions of ionic liquids with large metalloproteins, in particular hemocyanins (Hcs). At first, complexes of a Hc from Rapana thomasiana (RtH) with a series of biocompatible choline amino acid salts [Chol][AA] were obtained. Applying UV-vis spectroscopy, Fourier-transformed infrared spectroscopy and differential scanning calorimetry the effect of these organic salts on the structure and thermal stability of RtH was assessed. Then, the cytotoxic effect of RtH–[Chol][AA] on breast cancer cells (MCF-7) and 3T3 fibroblast cells (non cancerous) was evaluated. We found that all [Chol][AA] induced clear time- and concentration-dependent alterations in the RtH conformation. The conformation and the thermal stability of IL-modified RtH depend strongly on the type of the anion of the tested compounds. All [Chol][AA]-modified RtHs exhibited lower thermal stability than the native RtH. At the same time, we established a good correlation between the structure of RtH and its antitumor activity. Namely, RtH–[Chol][AA] complexes exhibited enhanced antiproliferative activity toward the MCF-7 cell line. The observed antiproliferative effect was cell specific and the compounds have no effect or in some cases have stimulatory effect on fibroblasts.

Rapana thomasiana hemocyanin modified with ionic liquids with enhanced anti breast cancer activity.

This is the first study on the surface modification of a hemocyanin from marine snail Rapana thomasiana (RtH) with series of imidazolium-based amino acid ionic liquids [emim][AA]. We monitored the induced by [emim][AA] conformational changes in RtH molecule and evaluated the effect of these ionic liquids (ILs) on the protein thermal stability. The cytotoxicity of all obtained RtH-[emim][AA] complexes was assessed toward breast cancer cells (MCF-7) and murine fibroblasts (3T3). As a whole, even small amounts of the tested ILs altered the secondary structure of RtH. The thermal denaturation of RtH in presence of [emim][AA] displayed multi-component transitions, which were shifted toward lower temperatures in comparison to those estimated for the native RtH. The profiles of the RtH-IL calorimetric curves show a clear dependence on the structure of the added salts. In addition, all RtH-[emim][AA] complexes exhibited an enhanced antiprofilerative activity of toward MCF-7 cells in comparison to that of the native RtH. The best results are observed for RtH-[emim][Leu], RtH-[emim][Trp] or RtH-[emim][Ile], which applied in concentration of 700 μg/mL inhibited the MCF-7 cell viability (for 24h) by 66, 63 and 53%, respectively. In addition, these IL-RtH complexes were less cytotoxic to 3T3 cells, i.e. they exhibited some cell specificity.

Efficient method for Knoevenagel condensation in aqueous solution of amino acid ionic liquids (AAILs)

Abstract This work reports on the use of the amino acid ionic liquids (AAILs) which have been used as catalysts in Knoevenagel condensation of various aldehydes with malononitrile. For research we use tetrabutylammonium ionic liquids based on eight natural amino acids. The reaction was carried out in an aqueous medium. Using water as solvent provided efficient and simple method of isolation of pure product with high yield. Moreover, amino acid ionic liquid dissolved in water could be reused many times without any loss of its catalytic activity. The influence of the anion was studied. Moreover the effect of technological parameters such as: the temperature, the catalyst content, and the reaction time on yield of reaction were investigated.

Benzalkonium Salts of Amino Acids – Physicochemical Properties and Anti-Microbial Activity

Abstract New salts combining a benzalkonium cation and chiral amino acid anions were synthesized and characterized. The identification was performed by NMR spectroscopy. Properties such as temperature of phase transformation, specific rotation, thermal stability and surface activity and antimicrobial activity were determined and compared with that of benzalkonium chloride. Benzalkonium amino acids salts can be used as conditioners in cosmetics. It has been shown they have weak impact on symbiotic microorganisms which occupy a wide range of skin, and this confirms that they do not disturb the biological balance of human skin.

Preparation, properties and potential applications of a photocurable varnish with pleasant limonene smell

Abstract Photocurable materials which are obtained on the basis of urethane acrylate resins are often used in the industry for the production varnishes or protective coatings. The main disadvantage which is connected with the utilization of these varnishes is their unpleasant smell during the process of production and curing. This work presents the photocurable varnish which was obtained on the basis of aliphatic urethane acrylate and R-(+)-limonene. The utilization of this raw materials allows to obtain the smelling coatings. The aim of this work were the studies on the influence of limonene molecules on the mechanical properties of the UV-cured coatings. These studies showed that the coatings with limonene molecules retain their properties, and are characterized by the very good adhesion, cohesion and high gloss. These kinds of varnishes can be applied for preparation of appropriate protective coatings on the surface of wood, metals, and nail plates. These protective coatings have not only pleasure smell but also can have the bactericidal and fungicidal properties. The studies performed with Escherichia coli ATCC29425 and Candida albicans confirmed these properties.

Spectral assignment and proton transfer studies of N‐(R‐salicylidene)‐1‐amino‐1‐deoxy‐ d‐sorbitols

Schiff bases (1–9), derivatives of various o-hydroxyaldehydes and 1-amino-1-deoxy-D-sorbitol, are optically active compounds that can be studied as potential ligands for various metal complexes. The properties of the Schiff base complexes and especially their use as enantioselective catalysts are related to the structure of the ligands; therefore, the knowledge about factors crucial for structure of ligands like hydrogen bond and proton transfer processes can be important for the possible applications of studied compounds. In this report, we present studies concerning intramolecular hydrogen bonding and tautomeric equilibrium as well as full assignment of H and C NMR spectra and N NMR data of N-(R-salicylidene)-1-amino-1-deoxy-D-sorbitols, which can be useful in synthesis of various optically active metal complexes or chiral N-acyloxazolines. Schiff bases, derivatives of natural product like D-sorbitol, can be especially useful in synthesis of new chiral complexes because of the presence of carbon chain with several hydroxyl groups and possible formation of polydentate complexes. Additionally, recent studies concerning Schiff bases, derivatives of glucosamine, and their complexes deal usually with ring form of glucose moiety, only few deal with chain form.