Magdalena Wójciak-Kosior

Simultaneous voltammetric determination of paracetamol and ascorbic acid using a boron-doped diamond electrode modified with Nafion and lead films

The paper describes the fabrication and application of a novel sensor (a boron-doped diamond electrode modified with Nafion and lead films) for the simultaneous determination of paracetamol and ascorbic acid by differential pulse voltammetry. The main advantage of the lead film and polymer covered boron-doped diamond electrode is that the sensitivity of the stripping responses is increased and the separation of paracetamol and ascorbic acid signals is improved due to the modification of the boron-doped diamond surface by the lead layer. Additionally, the repeatability of paracetamol and ascorbic acid signals is improved by the application of the Nafion film coating. In the presence of oxygen, linear calibration curves were obtained in a wide concentration range from 5×10(-7) to 2×10(-4) mol L(-1) for paracetamol and from 1×10(-6) to 5×10(-4) mol L(-1) for ascorbic acid. The analytical utility of the differential pulse voltammetric method elaborated was tested in the assay of paracetamol and ascorbic acid in commercially available pharmaceutical formulations and the method was validated by high performance liquid chromatography coupled with diode array detector.

Application of solid phase extraction with the use of silica modified with polyaniline film for pretreatment of samples from plant material before HPLC determination of triterpenic acids

The new sorbent based on silica gel coated with a film of polyaniline (Si-PANI) was obtained in a process of in situ polymerization directly on carrier particles and its potential application for pretreatment of plant material samples with the use of solid phase extraction (SPE) was investigated. Parameters such as cartridge conditioning, the volume and concentration of the sample, the type and volume of the elution solvent were optimized and compared with parameters obtained for RP-18 and aminopropyl silica cartridges. The high recovery values above 97% after the SPE procedure with the use of Si-PANI cartridges proves their utility for analysis of triterpenic acids. The sorbent tested was successfully used for clean-up of extracts from Salvia officinalis L., Syzygium aromaticum (L.) Merrill., and Origanum vulgare L. prior to HPLC-DAD determination of oleanolic, ursolic and betulinic acid. The efficiency of sample purification was verified by monitoring of chromatograms in the region between 190 nm and 400 nm during the gradient elution. The fewest components or their lowest concentrations were observed for all the investigated samples after the SPE procedures.

The effect of ursolic and oleanolic acids on human skin fibroblast cells

In this article, we look at how ursolic and oleanolic acids can be used for the purpose of quality control of natural products used in dermatocosmetology as well as of various other therapeutic preparations. Ursolic acid (UA) and oleanolic acid (OA) are pentacyclic triterpenes and they are constituents of many medicinal herbs. In this study, we analyzed the cytotoxic and anti-proliferative activity of OA and UA against normal human skin fibroblasts (HSF). Additionally, the scavenging activity of free radicals of both acids was analyzed. The sensitivity of cells to OA and UA activity was determined using a standard spectrophotometric (MTT) assay. The free radical scavenging activity of OA and UA was measured using the DPPH• test. The F-actin cytoskeletal proteins organization was analyzed using TRITC-phalloidine fluorescent staining. The cytotoxic activity of the analyzed acids was determined using Neutral Red (NR) uptake assay. Of the two isomeric compounds, UA showed a higher cytotoxic activity against HSF cells than did OA. Our investigations showed that OA, in view of its non-toxic nature, may be used as a supplementary factor for dermal preparations.

Physicochemical properties of silica gel coated with a thin layer of polyaniline (PANI) and its application in non-suppressed ion chromatography

Physicochemical properties of a new sorbent and its potential application in non-suppressed ion chromatography (IC) have been investigated. The sorbent was obtained in a process of covering silica gel particles with a film of polyaniline (PANI). The properties of silica modified with polyaniline such as particle size, porosity, average quantity of polyaniline covering carrier and density of sorbent were determined. In our study the following methods were used: microscopic analysis, laser diffraction technique, combustion analysis, mercury porosimetry and helium pycnometry. Column with the newly obtained packing was used for the separation of inorganic anions. Optimized chromatographic system was successfully employed for analysis of iodide and bromide in selected pharmaceutical products (Bochnia salt and Iwonicz salt) applied in chronic respiratory disease. Analysis was carried out using 0.1M solution of HCl in mixture of methanol/water (50:50v/v) as a mobile phase; the flow rate was 0.3 mL min(-1), temperature was 24°C and λ=210 nm. Validation parameters such as correlation coefficient, RSD values, recovery, detection and quantification limits were found to be satisfactory.

Synthesis and properties of a newly obtained sorbent based on silica gel coated with a polyaniline film as the stationary phase for non-suppressed ion chromatography

The new sorbent for non-suppressed ion chromatography based on silica gel coated with a film of polyaniline (PANI) was obtained in a process of in situ polymerization of aniline by oxidation with ammonium peroxydisulfate. Raman analyses performed using a Thermo Scientific DXR confocal Raman Microscope equipped with the Omnic 8 software from Thermo Fisher Scientific have proved a uniform distribution of PANI on the surface of chromatographic beads and in the pores of the particle. The obtained stationary phase was packed into a stainless steel HPLC column. The quality of the prepared column was verified on the basis of hydrodynamic parameters such as column efficiency index (Ip) and separation impedance (E). The potential application of silica gel modified with polyaniline for separation and determination of selected anions using non-suppressed ion chromatography was also investigated. Chromatographic analyses were performed using of the ion chromatograph Dionex DX-500. The best results were obtained for the mobile phase consisting of an aqueous or methanolic solution of hydrochloric acid. The tested column and optimized chromatographic system were successfully used for the analysis of nitrate, bromide and iodide in waters samples.

Thin-layer chromatography of phenolic acids on aminopropylsilica

The possibility of using aminopropylsilica TLC plates for determination of phenolic acids has been investigated. Eighteen phenolic acids were chromatographed on aminopropyl-bonded silica with mobile phases comprising mixtures of diisopropyl ether and acetic acid with toluene, petroleum ether, or heptane. The selectivity of the proposed chromatographic systems was satisfactory. The best separations were obtained with heptane–diisopropyl ether–acetic acid, 4 + 5 + 1 (v/v) or petroleum ether–diisopropyl ether–acetic acid, 6 + 3 + 1 (v/v) as mobile phase.

Application of a new technique in two-dimensional TLC separation of multicomponent mixtures

In this publication a new technique in planar chromatography is presented. The technique connects two-dimensional chromatography with multiple gradient development. It enables separation of multicomponent mixtures such as plant extracts with simultaneous qualitative identification of components. On the same plate less polar aglycones and more polar glycoside derivatives can be identified simultaneously. The new technique was applied to analysis of anthraquinone derivatives in Rhamnus frangulae cortex methanol extract.

Biofortification of soy (Glycine max (L.) Merr.) with strontium ions.

Soy (Glycine max (L.) Merr.) is an annual plant cultivated worldwide mostly for food. Moreover, due to its pharmacological properties it is widely used in pharmacy for alleviating the symptoms of osteoporosis. The aim of the present study was to investigate the biofortification of soy treated with various concentrations of strontium. Soy was found to have a strong capacity to absorb Sr(2+) (bioconcentration factor higher than 1). A positive linear correlation (R(2) > 0.98) between the amount of strontium in the growth medium and its content in the plant was also observed. Moreover, at a concentration of 1.5 mM, strontium appeared to be nontoxic and even stimulated plant growth by approximately 19.4% and 22.6% of fresh weight for shoots and roots, respectively. Our research may be useful to obtain vegetable products or herbal preparations containing both phytoestrogens and strontium to prevent postmenopausal osteoporosis.

Analysis of glycosides and aglycones of flavonoid compounds by double-development thin-layer chromatography

Flavonoid glycosides are much more polar than their aglycones and the two groups of compounds are difficult to separate by planar chromatography owing to the ‘general elution problem’ - glycosides require development with mobile phases of higher eluent strength. The problem of separating both groups can be solved by gradient elution or by incremental gradient multiple development in its simplest form - double development. The latter technique is illustrated for nine glycosides and seven aglycones by development along two-thirds of the plate length with a strong mobile phase and, after evaporation of the solvent, development to the full distance with a weaker mobile phase. The two stages of development are illustrated by densitograms.

Proliferative and antioxidant activity of Symphytum officinale root extract

Abstract The root of Symphytum officinale L. is commonly used in folk medicine to promote the wound healing, reduce the inflammation and in the treatment of broken bones. The objective of our investigation was to analyse the extract from S. officinale in term of its antioxidant activity and the effect on cell viability and proliferation of human skin fibroblast (HSF). Moreover, the quantification of main phenolics and allantoin was conducted using HPLC–DAD method. Five compounds were found: rosmarinic, p-hydroxybenzoic, caffeic, chlorogenic and p-coumaric acid. DPPH, FRAP and TPC assay showed the high antioxidant activity of the extract. MTT test proved the stimulatory effect on cell metabolism and viability of HSF cells. Moreover, no changes in cytoskeleton structure and cells shape were observed. The obtained results indicate that non-toxic extract from S. officinale root has strong antioxidant potential and a beneficial effect on human skin fibroblasts.