Mass spectrometry of biologically active substances

The mass spectra of 2- and 4-iminobarbituric acid derivatives were studied in relation to the mass spectra of their oxygen analogs. It is shown that the pathways of fragmentation of the investigated compounds depend on the type of substituent attached to the C₅ atom, the position of the imino and oxo groups in the ring, and the specific mass-spectral properties. The fragmentation was studied by means of low-voltage mass spectrometry and deuterium labeling.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 813–817, June, 1978.     

Inedible mushrooms: a good source of biologically active substances

In the course of our investigation on biologically active substances from inedible mushrooms in Japan, Germany, and Vietnam, we studied the chemical constituents of 22 species belonging to five families: Scutigeraceae, Polyporaceae, Xylariaceae, Thelephoraceae, and Paxillaceae. Various types of chemical substances were purified and characterized based on the modern spectroscopic methods and also on chemical reactions. These metabolites have shown a broad activity in many biological systems, such as antimicrobial, nematicidal, inhibition of NO production, anti-human immunodeficiency virus, tumor necrosis factor-alpha, and antioxidant activities. These isolated metabolites did not only show interesting activities, but also are employed as chemical markers supported for chemosystematics of these families. This review paper deals with the chemical constituents of 22 species, their biological activities, and also a discussion on chemosystematics.     

Determination of organic odor-forming substances using a multisensor system

A multisensor system based on an array of weakly selective sensors is applied to the determination of organic odor-forming substances. Polyethylene glycol esters (succinate, sebacate, and adipate), polystyrene, β-alanine, Triton X-100, Apiezon L, bis-(2-cyanoethyl) ether, and dicyclohexano-18-crown-6 are studied as modifiers of electrodes of mass-metric piezoelectric resonators. Using curdy whey as an example, we illustrate the visualization of “images” of odor-forming components. The shape of visual images is governed by the sensitivity of sensors and independent of concentration.     

Degradation of biologically active substances by vapor-phase hydrogen peroxide

We have examined the potential of vapor-phase hydrogen peroxide (VPHP) for degradation of 21 structurally different pharmaceutical substances. Our results show that VPHP can be used to degrade pharmaceuticals, but it was not universally applicable to all the drugs tested. Structural analysis revealed a significant correlation of the molecular structure of a compound with its susceptibility to VPHP. Tertiary amino groups seem to be the initiation centers, although the overall susceptibility of a substance depends on other factors also. Several tested substances underwent significant structural changes, suggesting a possible decrease in their biological activity. As far as we are aware, this is one of the first reports of application of VPHP to the decontamination of hazardous chemicals.     

Solid-phase microextraction-gas chromatography-mass spectrometry of biologically active substances in water samples

High-flow pneumatically assisted electrospray ionization mass spectrometry (ESI-MS) has been extensively used for the characterization and determination of peptides and peptide hormones available for biomedical research and therapeutic applications. The aim of this study was to optimize a method of characterization and determination of a mixture of peptide hormones with therapeutic interest by liquid chromatography (LC) coupled to ESI-MS. In this work the linear solvation energy relationship methodology was used in order to optimize the mobile phase to be used in the LC separation of the peptide hormone series and the operational parameters of the source and analyzer of ESI were also optimized to obtain the best signal stability and the highest sensitivity. To validate the proposed method for peptide hormone analysis, quality parameters were determined and satisfactory results were obtained. Likewise, the method detection limit was picomole level for most of the peptides employing selected-ion monitoring of the [M+nH]n+ ions.     

A kinetic determination of ultramicroquantities of some biologically active substances

A new kinetic method for the determination of ultramicroquantities of adrenaline, noradrenaline, thyroxine, and 5-hydroxytryptophan is presented. The method is based on the effect of these organic substances on the oxidation of pyrocatechol violet with hydrogen peroxide, catalyzed by Cu(II) ions.In order to find out the experimental conditions under which this effect is optimum, the kinetics of the above-mentioned indicator reaction in the presence of the compounds to be determined was studied in detail.Adrenaline and noradrenaline were determined at concentrations ranging from 2.0 × 10^?6 to 8.0 × 10^?6M, thyroxine at concentrations varying from 1.0 × 10^?6 to 10.0 × 10^?6M, and 5-hydroxytryptophan over the concentration range 7.7 × 10^?7–32.0 × 10^?7M. In these determinations the standard deviation was lower than 10%.     

Determination of organic odor-producing substances in a gas mixture using a multisensor system

A multisensor system based on an array of weakly selective sensors was used to determine organic odor-producing substances in gas mixture. As modifiers of electrodes of mass-metric piezoelectric resonators served polyethylene glycol esters (succinate, phthalate), tris(hydroxymethyl)aminomethane, N-methyl-2-pyrrolidone, polyphenyl ether, sodium nitroprusside, sulfosalicylic and ribonucleic acids, and diphenylcarbazide. For the example of a biotechnological object, true milk solution, visual “patterns” of odor-producing components were constructed. Their type is determined by the sensitivity of the sensors and is independent of the concentration of the substances under study.     

Obtaining biologically active substances from Amaranthus caudatus L. seeds in one technological cycle

Nowadays, amaranth is a valuable multipurpose crop and a source of a number of very important biologically active substances. The aim of this study was to develop a comprehensive scheme for obtaining fatty oil, triterpenoids and lectin from the seeds of Amaranthus caudatus L. in one technological cycle. Two variants of the lectin and triterpene compound purification method from amaranth seeds were tested. It was determined that the extraction of triterpene compounds should be carried out after purification of the lectin from degreased seeds. The rationality of this sequence of technological operations is explained by the lability of the lectin and the insolubility in water of triterpene compounds from amaranth seeds. The study also presents a scheme for obtaining squalene from amaranth oil by chromatography on silica gel and proposes a more effective affinity sorbent for purification of the lectin. The use of such a sorbent also opens up the possibility of preserving other water-soluble substances from amaranth seeds. The physicochemical characteristics and carbohydrate specificity of the lectin are described and new data on the results of the interaction of lectin with human and animal erythrocytes are given. The obtained results are discussed in the light of the complex use of raw materials.     

Determination of halogen species of humic substances using HPLC/ICP-MS coupling

A mass spectrometric method for the determination of chlorine, bromine and iodine species of humic substances (HS) has been developed by coupling a HPLC system with ICP-MS. Using size exclusion chromatography, the method was applied to the characterization of natural water samples (ground water, seepage water from soil, brown water) and a sewage water sample. Quantification of iodine/HS species was carried out by the on-line isotope dilution technique, which was not possible for bromine and chlorine species because of mass spectroscopic interferences by using a quadrupole ICP-MS. Characteristic fingerprints of the halogen/HS species, correlated with the corresponding UV chromatogram, were obtained dependent on the different origin of HS. Biological influences were indicated when following changes of the iodine/HS species composition by aging. The formation of iodine/HS species from inorganic iodide was investigated by labelling experiments with an ¹²⁹I^– spike solution, resulting in the finding that specific HS fractions are preferably iodinated.     

Study of biologically active amines in grapes and wines by HPLC

Summary The biologically active amines agmatine, cadaverine, histamine, phenethylamine, putrescine, spermidine, and tyramine have been determined in different varieties of grape, aszu grape, wine and aszu wine from the Tokaj region of Hungary. Ion pairs formed between the amines and octanesulphonic acid were separated by liquid chromatography on a μBondapak C₁₈ reversed-phase column, and spectrofluorimetric detection was performed after post-column derivatization witho-phthalaldehyde and 2-mercaptoethanol. The method was linear for the amines between 0.1 and 10 mg L⁻¹, and for spermidine between 1 and 30 mg L⁻¹. Comparison of the results revealed that the qualitative and quantitative content of biologically active amines was mostly determined by the vintage of the wine and the technology used for wine-making. The biogenic amine content of Tokaj wines is well below suggested limits for any of the amines, showing that the wine-making technology of the Tokaj region is of high quality. The levels of biologically active amines (identified and quantified by HPLC) in grapes, wines and aszu wines can provide useful information about the weather, growth ofBotrytis cinerea in Tokaj, and aspects of the methods used for wine-making. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Mechanochemical interaction in systems constituted by biologically active substances and layered silicate

IR spectroscopy was used to study the process of a mechanochemical interaction of glucose, sorbite, and cetyl alcohol with natural layered silicates. It was found that mechanocomposites with a chemical bond between the components are formed in the course of activation of the systems. The only exception is the mixture of cetyl alcohol and kaolinite because, being even weaker acids than water, monoatomic alcohols react similarly to water only with alkali and alkaline-earth metals. The data obtained can be used in development of medicinal cosmetic preparations.     

Structure of a matrix based on polysaccharide derivatives for the immobilization of biologically active substances

The supermolecular, molecular, and physicochemical characteristics of natural and modified natural polysaccharides (cotton cellulose, amylose of the U-type) used as supports for obtaining enzyme conjugates have been studied. It has been shown that by varying the process conditions it is possible to obtain cellulose matrices with different amounts of CHO groups and correspondingly different capacities for immobilizing an enzyme and modifying its activity.Institute of the Chemistry and Physics of Polymers, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 44 26 61. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 632–638, July–August, 1997.     

Control of the synthesis of some biologically active substances by thin-layer chromatography

Summary The aim of this investigation was the synthesis of -aryl propionic acids which might be expected to have antiinflammatory activity. The total synthesis of -(4-benzoylphenyl)--methyl propionic acid was monitored by thin-layer chromatography. The adsorption of the compounds of interest was found to be dependent upon the polarity of the eluting solvents. The observed retentions were mathematicaly analysed, and the system that showed the best separation of reactants evaluated. A least squares method was used to determine the best geometric curve expressing the relationship between values for R_f and eluent composition.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Determination of the active metabolites of sibutramine in rat serum using column-switching HPLC

A simple and direct analysis using column-switching HPLC method was developed and validated for the quantification of active metabolites of sibutramine, N-mono-desmethyl metabolite (metabolite 1, M1) and N-di-desmethyl metabolite (metabolite 2, M2) in the serum of rats administered sibutramine HCl (5.0 mg/kg, p.o.). Rat serum was directly injected onto the precolumn without sample prepreparation step following dilution with mobile phase A, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (8.3:4.5:87.2 by volume). After the endogenous serum components were eluted to waste, the system was switched and the analytes were eluted to the trap column. Active metabolites M1 and M2 were then back-flushed to the analytical column for separation with mobile phase B, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (35.8:19.2:45 by volume) and detected at 223 nm. The calibration curves of active metabolites M1 and M2 were linear in the range of 0.1-1.0 microg/mL and 0.15-1.8 microg/mL. This method was fully validated and shown to be specific, accurate (10.4-10.7% error), and precise (1.97-8.79% CV). This simple and rapid analytical method using column-switching appears to be useful for the pharmacokinetic study of active metabolites (M1 and M2) of sibutramine.     

Investigation of antioxidant and catalytic properties of some biologically active substances by voltammetry

Antioxidants play a major role in protecting biological systems against many incurable diseases. The biological activity of 12 plant aqueous-alcohol extracts, some standard antioxidants (vitamin C, glucose, resorcinol, and catechol), Na(2)SO(3), humic acids, phthalocyanines, and chlorophyll have been investigated in this work together with evaluation of their influence on the kinetics of the oxygen electroreduction. Finally the use of these substances for prophylactic purposes has been recommended.     

Determination of homologues anion surfactants in technical preparations using a multisensor system and HPLC

New potentiometric solid-contact sensors with polyvinyl chloride membranes based on compounds of alkyl sulfates with cationic complexes copper(II)–organic reagent are proposed for the determination of synthetic anionic surfactants (ASs). Multisensor systems are developed for the quantitative determination of ASs in raw technical preparations (alkylbenzene sulfonates, alkyl sulfates, and sodium cocosulfate).     

Bioassay techniques: Problems concerning the selectivity and sensitivity of determining biologically active substances

A new biochemical approach was developed in order to improve the selectivity and sensitivity of determining biologically active substances. This approach is based on changes in the biological activity of analytes in the course of sample preparation. Other techniques for solving the above problem, namely, an increase in the temperature of the test solution temperature or the use of solvent extraction, bioaccumulation, and unusual analytical procedures are also considered.     

Monitoring of biologically active amines in cereals and cereal based food products by HPLC

Summary Biologically active amines (putreanine sulphate, N-acetyl putrescine, putrescine, cadaverine, histamine, agmatine, N-acetyl spermidine, spermidine, spermine) were separated and quantified in cereal flour and cereal products by a liquid chromatographic method. The method consists of the separation of ion pairs formed between biologically active amines and octanesulphonic acid on a reversed-phase column, postcolumn derivatization with o-phtalaldehyde-2-mercapthoethanol and spectrofluorometric detection. Results of the reliability study were satisfactory. The method was linear for each amine at 1–10 mg L⁻¹. Putrescine and spermidine were the only amines always detected in cereal flour and cereal products, ranging from 2.45 to 47.83 mg kg⁻¹ for putrescine and 3.27 to 37.14 mg kg⁻¹ for spermidine. The most important differences among types of samples were found in polyamine derivatives. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.