Ryszard Świeboda

Lipophilicity of novel antitumour and analgesic active 8-aryl-2,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazine-3,4-dione derivatives determined by reversed-phase HPLC and computational methods

Eight novel antitumour and analgesic active 8-aryl-2,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazine-3,4-diones (1-8) have been obtained as a bioactive set of substances and their lipophilicity has been studied. The logk values of fifteen reference compounds and eight newly synthesised imidazotriazine-3,4-dione derivatives were determined by reversed-phase high performance liquid chromatography (RP-HPLC) using mixtures of methanol and water as mobile phases with different methanol concentrations. The relationships between logk values of a set of reference compounds (fifteen compounds) and investigated ones (eight compounds) and concentration of methanol was used for determination of the logkwater values by extrapolation. The partition coefficients (logP) values for reference compounds measured experimentally were taken from the literature. The calibration equation was then obtained for the standards of known lipophilicity (logPHPLC) and logkwater. In next step the partition coefficients of new synthesised solutes were calculated from the calibration equation. For the comparison purpose, additionally the partition coefficients (logPcalc.) of the examined imidazotriazine-3,4-diones were calculated by means of the Pallas 3.1.1.2. software. It was found that logkwater values as a lipophilicity measure of derivatives correlate well with partition coefficients measured experimentally (logPHPLC). Correlation between the logPHPLC and the logarithm of partition coefficient calculated by Pallas software (logPcalc.) is not so satisfactory as that for values determined experimentally. Furthermore, it has been found that the lipophilicity variation of investigated imidazotriazine-3,4-diones (1-8) correlates well with their acute toxicity expressed as log(1/LD50). The drug-likeness of all the bioactive 8-aryl-2,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazine-3,4-diones was assessed on the basis of their structural properties by applying Lipniskis rule of five. The solutes have all four parameters important for the favourable pharmacokinetics in the human body that would make them likely orally active drugs in humans.

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.

The Stimulatory Effect of Strontium Ions on Phytoestrogens Content in Glycine max (L.) Merr

The amount of secondary metabolites in plants can be enhanced or reduced by various external factors. In this study, the effect of strontium ions on the production of phytoestrogens in soybeans was investigated. The plants were treated with Hoagland’s solution, modified with Sr2+ with concentrations ranging from 0.5 to 3.0 mM, and were grown for 14 days in hydroponic cultivation. After harvest, soybean plants were separated into roots and shoots, dried, and pulverized. The plant material was extracted with methanol and hydrolyzed. Phytoestrogens were quantified by HPLC. The significant increase in the concentration of the compounds of interest was observed for all tested concentrations of strontium ions when compared to control. Sr2+ at a concentration of 2 mM was the strongest elicitor, and the amount of phytoestrogens in plant increased ca. 2.70, 1.92, 3.77 and 2.88-fold, for daidzein, coumestrol, genistein and formononetin, respectively. Moreover, no cytotoxic effects were observed in HepG2 liver cell models after treatment with extracts from 2 mM Sr2+-stressed soybean plants when compared to extracts from non-stressed plants. Our results indicate that the addition of strontium ions to the culture media may be used to functionalize soybean plants with enhanced phytoestrogen content.

High-Resolution Continuum Source Atomic Absorption Spectrometry with Microwave-Assisted Extraction for the Determination of Metals in Vegetable Sprouts

The goal of this study was to investigate the enrichment of garden cress (Lepidium sativum), mung beans (Vigna radiata), and soybeans (Glycine max) with minerals. Hydroponic nutrient solutions were enriched with Zn2+,Cr3+, Ca2+, Mg2+, and Se2+. Morphological assessment was based on monitoring changes that occurred as a function of the concentrations of elements in the medium. The growth of the plant, as a result of a stimulating or inhibitory effect of the identity and concentration of elements on the germination process, was characterized. Microbiological contamination was identified and catabolic profiles of two bacterial strains were performed. High-resolution continuum source atomic absorption spectrometry (HR-AAS) was used to determine Zn2+, Cr3+, Ca2+, Mg2+, and Se2+ in dried plant material after sample pretreatment using microwave-assisted extraction. The limits of detection were 0.010, 0.029, 0.013, 0.151, and 0.030 milligram per liter for Ca2+, Cr3+, Mg2+, Se2+, and Zn2+, respectively. Recoveries were higher than 98 percent and the relative standard deviation was less than 5 percent. The accuracy of the procedure was estimated by analyzing certified reference materials. The results showed that biofortification of garden cress by zinc holds the highest promise for the creation of designer foods. Garden cress was found to have the highest bioconcentration factor among the investigated plants; at 50 parts per million, plant growth was stimulated without contamination by microorganisms.

Chromatographic and Calculation Methods for Analysis of the Lipophilicity of Newly Synthesized Thiosemicarbazides and their Cyclic Analogues 1,2,4-Triazol-3-thiones

This paper describes the evaluation of the lipophilicity of newly synthesized thiosemicarbazides and their cyclic analogues 1,2,4-triazol-3-thiones obtained using experimental and calculated methods. Previous studies have shown these compounds have antibacterial activity. The chromatographic behavior of analyzed compounds was studied by reversed phase high performance liquid chromatography (RP-HPLC) and reversed phase thin layer chromatography (RP-TLC). The aqueous mobile phases containing methanol were used in order to determine retention parameter (RM) and capacity factors (log k) of analyzed compounds. The lipophilicity parameters were obtained by linear extrapolation and they were compared with the calculated log P obtained using several software packages. The results indicate that both experimental chromatographic methods yielded similar results, and these methods are appropriate for determining the lipophilicity of analyzed compounds. High values of correlation coefficients between the log P values calculated using known algorithms (milogP, ALOGPs, AClogP, AlogP, MLOGP, KOWWIN, XLOGP2, XLOGP3) and the experimental data were obtained. Eight standard solutes with known log POW were analyzed under the same conditions as the tested substances in order to determine the log PHPLC and log PTLCparameters. A good correlation was obtained between log kw (or RMW) and the slope. All tested compounds were in agreement with the rule of five claims by Lipinski. The calculated log P values were experimentally confirmed (log PHPLC and log PTLC).

TLC Profiles of Selected Cirsium Species with Chemometrics in Construction of Their Fingerprints.

The dried aerial parts of 12 plants of Cirsium species were extracted with the Soxhlet apparatus using dichloromethane and methanol as solvents. Next, the extracts were separated by TLC methods to obtain the fingerprint chromatograms. The analysis was performed on silica gel or RP-18 layers as stationary phases using the following eluents: ethyl acetate/formic acid/acetic acid/water (12/1.5/1.5/4; v/v) for silica gel, and 5% (v/v) aqueous solution of formic acid/methanol (70/30; v/v) for the first development and the same system in the proportion of 50/50 (v/v) for the second development for RP-18. The double development was applied in the case of RP-18 plates. The analysis was performed for all Cirsium methanolic extracts and five selected standards (naringin, apigenin, rutin, caffeic acid and chlorogenic acid). The results were analyzed using chemometrics. The comparison of individual Cirsium species and the identification of unknown species were performed using the similarity indices (Pearsons correlation coefficient, determination coefficient and congruence coefficient), distance indices (Euclidean distance, Manhattan distance and Chebyshevs distance) and Multi-Scale Structural SIMilarity. Based on chemometric analysis, the first extract of the widely grown species is identified as Cirsium arvense and the second one as Cirsium rivulare.

HPLC Identification of Copper (II)-Trans-Resveratrol Complexes in Ethanolic Aqueous Solution.

Reversed-phase high-performance liquid chromatography assay with the diode array detector was applied for detection of trans-resveratrol complexes with copper (II). Two complexes with copper to resveratrol ratio 3:2 and 1:1 were identified in ethanolic-aqueous solutions in neutral and acidic conditions. The matrix-assisted laser desorption ionization-time of flight mass spectrometry was used for evaluation of complexes in eluate liquid fraction. The structures of complexes were modeled by Titan, Spartan and HyperChem software. The findings obtained satisfactorily explain the chromatographic data and could provide useful an additional data about these forms in which is present trans-resveratrol in wine (free and/or forming complex with copper).

Micro Two-Dimensional Thin-Layer Chromatography and Chemometric Analysis of Essential Oils from Selected Mentha Species and Its Application in Herbal Fingerprinting

Micro two-dimensional thin-layer chromatographic systems (micro-2D-TLCs) were optimized using some popular nonaqueous mobile phases on 5 cm × 5 cm silica plates. The optimal 2D TLC systems were chosen based on correlations of RF values vs. mobile phases concentrations performed for 1D separations. Finally plates were developed using the following mobile phases: in the first direction – ethyl acetate/toluene (5/95; v/v) and in the second direction – ethyl acetate/n-heptane (15/85; v/v). Eleven essential oils obtained by hydrodistillation in Deryng apparatus from various mint specimens were separated and then 2D thin-layer chromatograms were densitometrically scanned at the wavelength of 254 nm. Digital images (exported from densitometer software as ASCII files) were processed using ImageJ free software, and then some chemometric parameters were calculated (determination coefficient, congruence coefficient, Euclidean’s distance, Manhattan’s distance, Chebyshev’s distance) and additionally, principal component analysis (PCA) was performed to determine the goodness of matching for individual essential oils. The chemometric analysis allows one to identify individual essential oils and the examined plant materials.

Chemometric analysis based on high-performance liquid chromatographic data in the fingerprint construction of selected Achillea species

ABSTRACT Fourteen Achillea species were collected, extracted using Soxhlet apparatus with dichloromethane and methanol as solvents. The obtained methanolic extracts were analyzed using the reversed-phase high-performance liquid chromatography–diode array detector (RP-HPLC-DAD) with the Kinetex C18 column and the mobile phase consisting of methanol–water–0.1% formic acid mixture (gradient 5–85% (v/v)) at 30°C with the run time of 45 min and the detection wavelength 320 nm. Next, the chromatograms were preliminarily processed with smoothing, noise reduction, background subtraction, and alignment in the SpecAlign program (version 2.4.1) to construct the fingerprints of studied extracts. Selected standards (phenolic acids and flavonoids) were analyzed in the same chromatographic conditions and its presence in extracts was confirmed based on their spectra and the retention time values. The chemical similarity between the samples was evaluated using the Pearson correlation coefficient as similarity parameter, Euclidean distance index, the principal component analysis, and cluster analysis (CA). GRAPHICAL ABSTRACT

Determination of Lipophilicity of New Thiosemicarbazide and 1,2,4-triazole-3-thione Derivatives Using Reversed-Phase HPLC Method and Theoretical Calculations

The lipophilicity of new thiosemicarbazide and 1,2,4-triazole-3-thione derivatives was determined using the RP-HPLC method, with the application of a mobile phase comprising methanol and water or acetonitrile and water. The logkW parameters were obtained by the extrapolation method using linear and quadratic equations. The lipophilicity data obtained experimentally (logkW, ϕ0) were compared with the calculated lipophilicity indices (logPHyperChem, milogP, clogP, ALOGPs, AClogP, AlogP, MLOGP, KOWWIN, XLOGP2, XLOGP3, logPChS). The matrices of these relationships were subjected to PCA analysis.