Optimisation of an extraction procedure and chemical characterisation of Croatian propolis tinctures.

Three spectrophotometric methods for the quantitative determination of different flavonoid groups and total phenolics in Croatian propolis samples were optimised and validated. The assay based on the formation of aluminium chloride complex (with galangin as a standard) was applied to the quantification of flavones and flavonols, while the 2,4-dinitrophenylhydrazine method (with pinocembrine as a reference) was used for the quantification of flavanones. Total phenolic content was measured by the Folin-Ciocalteau method using reference solution of caffeic acid:galangin:pinocembrine (1:1:1). Through analytical validation, the most suitable extraction conditions (with respect to time, temperature and concentration of extraction solvent) were determined, and final conditions for the extraction were established (80% ethanol, 1 h at the room temperature). The appropriate ratio between the mass of raw propolis and the extraction solvent volume was also established. By the application of the optimised method of extraction, 10 propolis tinctures were prepared and subjected to the analysis of general pharmacopoeial parameters, which are fundamental for the creation of quality specification (relative density, dry residue of extract, content of ethanol, methanol and 2-propanol). Additionally, the content of waxes as the main inactive constituents was determined in order to observe the level of their migration from crude propolis to the prepared tinctures.

Application of self-organizing maps for the classification of chromatographic systems and prediction of values of chromatographic quantities.

The applicability of self-organizing maps (SOM) for the classification of chromatographic systems or components of chromatographic systems based on data taken from literature is shown. The SOM approach is compared to dendrogram and principal components analysis (PCA) approaches. It has been shown that the distance between classified objects could reveal linear correspondence with quantity to be optimized, e.g. resolution, so it can be applied in the chromatographic method development. SOMs can also be applied for prediction of chromatographic quantities. It is shown that SOM-based response surface modeling is comparable to triangular presentation of mobile phase composition response surfaces.

The use of information theory and numerical taxonomy methods for evaluating the quality of thin-layer chromatographic separations of flavonoid constituents of Matricariae flos.

A methanol extract of Matricariae flos was analysed with regard to the flavonoid composition. Rational selection of a restricted set from eight chromatographic systems tested for the separation of these compounds is discussed. Series of mathematical techniques for the evaluation of solvents and solvent combinations in thin-layer chromatography of flavonoid constituents have been explored. The chromatographic systems are classified according to their mutual resemblance by numerical taxonomy techniques. The selection criterion in the groups, obtained by numerical taxonomy classification, is the information content or the discriminating power. The most suitable mobile phases for TLC separation of flavonoid constituents of Matricariae flos are: ethylacetate-methanol-water (75:15:0 v/v), ethylacetate-formic acid-water (80:10:10 v/v) and ethylacetate-formic acid-acetic acid-water (100:11:11:27 v/v).

Optimization of TLC analysis of flavonoids and phenolic acids of Helleborus atrorubens Waldst. et Kit.

Numerical methods for the evaluation of the separation power of thirteen thin-layer chromatographic systems for splitting a methanolic extract of leaves of Helleborus atrorubens Waldst. et Kit. into 15 compounds (flavonoids and phenolic acids) have been investigated. For this purpose, the following mathematical approaches have been applied: calculation of the information content (I), determination of discriminating power (DP) and formation of clusters and dendrogram. The most suitable chromatographic system for the separation of investigated compounds is ethyl acetate-formic acid-water (65:15:20, v/v/v).

Binding of (+)- and (-)-isomers and racemate of etomoxir to human serum albumin and effect of stearic acid and stanozolol.

Binding of (+)- and (-)-isomers and the racemate of sodium 2[6-(4-chlorophenoxy)-hexyl]-oxiran-2-carboxylate dihydrat (etomoxir) to the human serum albumin (HSA) was studied by the gel filtration method. The experimental results are presented graphically using the method of Scatchard. Measurements revealed the following data on the binding: (a) for either of the isomers there are two independent and nonequivalent classes of binding sites on the HSA molecule; (b) the binding constants calculated for both isomers were of the same order of magnitude (K1/n approximately 20 x 10(5) L.mol-1 for the concentration range 3.48-4.0 x 10(-5) mol.L-1, and K2/n approximately 2 x 10(5) L.mol-1 for the concentration range 4.28-10 x 10(-5) mol.L-1, for the high and low affinity binding sites, respectively); (c) statistically significant difference (p < or = 0.05) between the low affinity binding constant estimated for the (+)-isomer K2 = 1.9 +/- 0.1 x 10(5) L.mol-1) compared with the constants evaluated for the (-)-isomer and racemic etomoxir (2.6 +/- 0.1 and 2.9 +/- 0.2 x 10(5) L.mol-1, respectively); and (d) both isomers are bound into a high extent to the HSA molecule (i.e., at a ligand concentration of 3.48 x 10(-5) mol.L-1, the percent of binding was approximately 95% for the compound tested. When plotting the percent binding (% Cb) against the total concentration (Ctot), a statistically significant difference (p < or = 0.05) was obtained between the slope of the straight line for the (+)-isomer and those for other two compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary excretion and metabolism of orally administered mefenorex.

Metabolic pathways and the pharmacokinetic profile of mefenorex ((+/-)N-(3-chloropropyl)-1-methyl-2-phenylethylamine), and its main metabolite amphetamine (1-methyl-2-phenylethylamine) have been studied in two healthy volunteers, after a single oral dose of mefenorex (1.2 mg/kg body weight for a male subject and 2.4 mg/kg body weight for a female subject). Urinary concentrations were determined by gas chromatography (GC) and metabolite structure was identified by GC/MS following derivatization of urine extracts. The ratio of this metabolite to unchanged drug in urine samples, collected up to 5 h following administration, was essentially the same after either of the administered doses. The calculated Kel for mefenorex after the higher dose was in the range of 0.191-0.272 h-1, with a biological half life (t1/2) of 3.98-2.55 h, depending on the method of calculation used. The elimination of amphetamine was much slower with a Kel ranging from 0.039-0.073 h-1 and a t1/2 from 9.5-17.8 h. Depending on the dose administered, the rate constant of metabolite formation was 0.129 and 0.685 h-1 for low and high doses, respectively. Urinary excretion of Rondimen amounted to 11.9% within 72 h after administration. Of this amount, 1.5% represented unchanged drug and 10.4% represented metabolites. In addition to amphetamine 3 other metabolites were identified: p-hydroxy mefenorex, p-hydroxy amphetamine and p-hydroxy-m-methoxy mefenorex.

Antibacterial and antifungal activities of nitroxoline Mannich bases.

The in vitro activity of nitroxoline and its Mannich bases against bacteria and fungi was investigated. Nitroxoline and its derivative with diisopropylamine as an amino component, exhibited the highest antimicrobial activity. The optimum hydro/lipophilic properties (log P), both for antibacterial and antifungal activity, are about log P values of 2. The least effective compound was this nitroxoline Mannich base which has diethanolamine as an amino component.

[Biologically active azomethines. Delépine reaction with 1-chloromethylisatin; preparation of some 1-aminomethylisatinazomethines (author's transl)]. / Biologisch aktive Azomethine. Delépine-Reaktion mit 1-Chlormethylisatin (Darstellung einiger 1-Aminomethylisatinazomethine.

The authors describe the synthesis of I-aminomethylisatin (3) from [I-chloromethylisatin] (1) by means of the Delépine reaction. On condensation with aromatic aldehydes, 3 yields the azomethines 5--7. The azomethine 5 is converted into the corresponding thiosemicarbazone 9. Testing for mitodepressive activity showed that the compounds 5--7 are active. On testing in vitro for tuberculostatic effects, the compound 9 proved exceptionally potent.

Antibacterial and antifungal activities of isatin N-Mannich bases.

The antimicrobial and antifungal activities of 29 congeneric isatin N-Mannich bases were investigated by testing against standard test microorganisms and 21 pathogenic Gram-negative microorganisms. Considerable growth inhibition of Gram-negative bacteria and yeasts and slight inhibition of Gram-positive bacteria resulted when they were treated with the various N-Mannich bases of isatin and 5-nitroisatin, respectively.