Analytics, Properties and Applications of Biologically Active Stilbene Derivatives.

Stilbene and its derivatives belong to the group of biologically active compounds. Some derivatives occur naturally in various plant species, while others are obtained by synthesis. Resveratrol is one of the best-known stilbene derivatives. Many stilbene derivatives exhibit antimicrobial, antifungal or anticancer properties. A thorough understanding of the properties of this group of biologically active compounds, and the development of their analytics from various matrices, will allow for a wider range of applications. This information is particularly important in the era of increasing incidence of various diseases hitherto unknown, including COVID-19, which is still present in our population. The purpose of this study was to summarize information on the qualitative and quantitative analysis of stilbene derivatives, their biological activity, potential applications as preservatives, antiseptics and disinfectants, and stability analysis in various matrices. Optimal conditions for the analysis of the stilbene derivatives in question were developed using the isotachophoresis technique.

Analytics and Application of Biologically Active Pentacoordinate Electrostatically Stabilized Silanates.

The objective of this study was to synthesize information on the analytics, using two separation techniques, and the application of electrostatically stabilized silanate derivatives. They are biologically active, water-soluble, hydrolytically stable and biodegradable. Some of these compounds are used as plant growth regulators, while others, with higher molecular mass and lower electrophoretic mobility, are used in the form of terminating electrolytes in isotachophoresis, which is regarded as one of the green chemistry techniques. Two compounds were successfully used in the form of terminating electrolyte solutions, i.e. 4,4'-bis{1-(perhydroazepiniomethyl)[spirobi(1-sila-2,5-dioxacyclopentane-3-on)]at}, and 4,4'-bis{1-[(N,N-dimethyl)aminiomethyl]spirobi(1-sila-2,5-dioxacyclopentane-3-on)at} to isolate organic ionic substances with high molecular mass, e.g. derivatives of quinoline, stilbene and electrostatically stabilized silanates (ES-silanates). Establishing the best conditions for the analysis of these derivatives extends the possibilities of conducting research on their biological activity and miscellaneous applications. Furthermore, the terminating electrolytes used in the form of solutions of electrostatically stabilized silanates allow the analysis of both cationic and anionic forms.

Determination of Mercury Content in Surface Waters Using an Environmentally Non-Toxic Terminating Electrolyte.

The paper presents results of the research on the dynamics of changes in the concentration of mercury in surface waters. The importance of mercury as an environmental pollutant results from specific properties of this metal, many sources of contamination, volatility, mobility, stability and high toxicity of its specific chemical forms. Samples of surface water collected from three rivers: the Bug, the Liwiec and the Muchawka were analysed. The Muchawka River flows into the Liwiec River, which in turn is a tributary of the Bug River. The technique of isotachophoresis was employed, using a solution of a biodegradable and environmentally non-toxic derivative of electrostatically stabilised silanates as the terminating electrolyte. The highest average mercury concentration of 0.89 µg/dm3 was determined in water samples collected from the Bug River in January, whereas the lowest concentration of 0.42 µg/dm3 was recorded in water collected from the Muchawka River in September.

The challenge of separating and determining biologically active electrostatically stabilized silanates using the high-performance liquid chromatography technique.

We present the results of research on the optimal conditions for the separation and determination of newly obtained hypercoordinated compounds, which belong to the group of electrostatically stabilized silanates. The research involved five stationary and four mobile phases. The best selectivity was obtained using the graphite phase and the mobile phase consisting of acetonitrile/water (80/20). The maximum selectivity of the determined electrostatically stabilized silanates was 1.13 and 1.06 for (1), (2), (3); 1.10 and 1.15 for (4), (5), (6); and 1.12 and 1.15 for (7), (8), (9). The octadecyl phase (which is recommended as standard) did not yield satisfactory results.

New Applications and Analysis of (E)-Azastilbenes in Environmental Samples.

The paper collates and summarizes information on stilbene derivatives, i.e. (E)-azastilbenes, taking into account the new possibilities of their applications, inter alia, in the natural environment. (E)-azastilbenes are biologically active, which is of great importance to humans and the whole ecosystem. As evidenced by a number of studies, they show fungistatic, fungitoxic and, depending on the concentration, estrogenic properties. Due to their properties, (E)-azastilbenes are still of great interest to researchers, who have high hopes for their pharmacological use or the possibility of using them as antiseptics, disinfectants, or preservatives in various products, including the environmental ones. Because of the difficulties with their determination, the study assumes optimal conditions of (E)-azastilbenes extraction from environmental samples and the technique of isotachophoresis is employed for the first time in this type of analysis. The highest recovery values ranging from 83 to 97% were obtained on the aryl extraction columns. The range of linearity of the developed method on the naphthylpropyl column ranged from 5 to 300 µg/mL.

Analytics of Quinine and its Derivatives.

The objective of this study was to perform a synthesis and analysis of the most important information on quinine and its derivatives, which are still very important in the treatment of malaria. The analysis of stereoisomers of quinine and its derivatives was conducted using two techniques, high-performance liquid chromatography and capillary electrophoresis. Particularly noteworthy is the technique used for the determination of isotachophoresis, referred to as one of the so-called green chemistry techniques. Particular attention was paid to properties and the use of quinine and its derivatives in the treatment of malaria. The analytical part will supplement knowledge about quinidine, quinine, and cinchonidine, and will contribute to the growth of research on the so-much-needed drugs against malaria.

Release of bisphenol A and its derivatives from orthodontic adhesive systems available on the European market as a potential health risk factor.

INTRODUCTION: Treatment with fixed orthodontic appliances requires the application of adhesive systems to enable secure fastening of brackets and retainers to the surface of tooth enamel. The orthodontic bonding systems are similar in terms of chemical composition to dental filling materials, the chemical stability of which is not satisfactory. Particularly alarming is the release of bisphenol A and its derivatives to the external environment, which has been well-documented for materials used in conservative dentistry. OBJECTIVES: The aim of the study was an in vitro assessment of the release of biologically harmful bisphenol A and its derivatives from orthodontic adhesives available on the European market, as a potential health risk factor for orthodontic patients. MATERIAL AND METHODS: The study assessed levels of BPA, BPA polymers and Bis-GMA resin in eluates of six commonly used orthodontic adhesives: Light Bond, Transbond XT, Resilence, Aspire, GrenGloo and ConTec LC, obtained after one hour, 24 hours, 7 days and 31 days of material sample storage in water. The presence and concentration of the studied chemicals in the obtained solutions were identified using the HPLC method. RESULTS: The highest (p≤0.05) concentration of BPA at 32.10µg/ml was observed in the Resilence material eluates. The highest concentration of poly-bisphenol A was found in solutions obtained after incubation of ConTec LC adhesive at 371.90µg/ml, whereas the highest amount of Bis-GMA resin (425.07µg/ml) was present in Aspire material eluates. CONCLUSIONS: 1) In conditions of the current experiment it was demonstrated that most of the assessed orthodontic adhesive resins available on the European market and released into the outside environment - biologically harmful bisphenol A or its derivatives, posing a potential threat to the patients' health. 2) Release of BPA and its derivatives into aqueous solutions is the highest in the early stages of sample incubation.

HPLC analysis of potentially harmful substances released from dental filing materials available on the EU market.

INTRODUCTION: Incomplete cross-linking of composite dental materials leads to their susceptibility to degradation in the environment of non-organic and organic solvents, contributing to the release of chemical compounds which are potentially harmful to living organisms. OBJECTIVE: The aim of the study was an evaluation in in vitro conditions of releasing of potentially toxic substances from six dental composite materials available in EU countries. MATERIALS AND METHODS: The following compounds released from the samples stored in water were analyzed: bisphenol A (BPA), triethylene glycol-dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA) and ethylene glycol dimethacrylate (EDGMA). Analysis of the substances was performed with the use of high performance liquid chromatography, after the following incubation periods: 1 hour, 24 hours, 7 days and 30 days. RESULTS: Among the analyzed substances, after 1 hour of incubation, the highest average concentration was found for TEGDMA - 2045 µg cm(-3) (in Herculite XRV material), after 24 hours - for UDMA 4.402 µg cm(-3) (in Gradia Direct Anterior material) and after 7 and 30 days for TEGDMA: 8.112 and 6.458 µg•cm(-3) respectively (in Charisma material). CONCLUSIONS: The examined composites used for reconstruction of hard tissues of teeth remain chemically unstable after polymerization, and release potentially harmful substances in conditions of the present study. The dynamics of the releasing of potentially harmful substances is correlated with the period of sample storage in water.

Separation of benzyl derivatives of germanium for HPLC.

The paper presents interactions of mono-, di-, tri-, and tetrabenzyl derivatives of germanium with stationary phase surface and results from these processes of determination. As a final result of the work, optimal conditions of chromatographic separation and determination of these compounds by high-performance liquid chromatography (HPLC) method are proposed. During investigations, different types of stationary phase (including octadecyl, octyl, and chemically bonded aryl phases) and mobile phases are considered. As a result of the investigation, the highest selectivity is showed chemically by bonded aryl stationary phase combined with a mobile phase consisting of acetonitrile (capacity factors of di-, tri-, and tetrabenzyl derivatives of germanium k(1) = 0.86, k(2) = 2.53, k(3) = 6.45). However, octadecyl phase, which is considered as reference phase, exhibits the lowest separation factors of determined benzylgermanium compounds (k(1) = 9.12, k(2) = 37.62, k(3) = 70.43).