A kinetic determination of ultramicroquantities of papaverine

A kinetic method for the determination of ultramicroquantities of papaverine based on its activator action on the reaction between hydrogen peroxide and cobalt(II) in carbonate buffer solution is presented. Kinetic equations of the reaction studied in the presence of and in the absence of papaverine were postulated and their apparent rate constants, activation energies, and thermodynamic parameters were calculated. The reaction rates were followed photometrically. Papaverine was determined in concentrations ranging from 1.0 to 12.0 μg/ml, with relative standard deviation from 1.8 to 8.5%. The effect of related substances from the opium alkaloid group on this determination was estimated. The described method was applied for the determination of papaverine in urine samples as well.     

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     

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.     

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.     

Carrier-bound biologically active substances and their applications

Stable catalysts can be obtained by fixation of enzymes on suitable supports. The principal methods for their preparation and their properties are described. The use of supported enzymes in routine biochemical analysis as “insoluble reagents” for automatic analyzers and for enzyme electrodes appears particularly interesting. For preparative transformations and syntheses, the supported enzymes offer the advantage that many processes that were formerly operated batch-wise can be run continuously to give protein-free products. The use of supported proteinases as specific adsorbents provides a simple method for the isolation of various naturally occurring inhibitors. This principle, which is the basis of affinity chromatography, has now also been adapted to the purification of enzymes and other biologically active substances on suitable supported effectors.     

Conformation of some biologically active aromatic ureas

Experimental IR spectroscopic data for the N-H stretching mode frequencies for several types of tri-substituted ureas containing benzyl and/or phenyl substituents as well as theoretical results from B3LYP/6-31G(d,p) computations on selected compounds provide sufficient evidence to determine the conformational state of these molecules. Two types of N-H bands may be found the spectra: (a) A type band due to a classical trans conformation (trans I) of the CONH structure; (b) B type band arising from an alternative trans form (trans II), in which the N-H band is involved in a hydrogen bond like interaction with the aromatic ring at the neighbouring nitrogen atom (benzyl or phenyl substituents). The N-H band of trans ICONH structure is observed at frequencies higher than 3460 cm-1, the actual position depending on weather the non-substituted N-H group is linked to aryl or alkyl substituents. The N-H band of the trans II rotameric structure is observed at 3430-3420 cm-1.     

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.     

Complexes derived from some biologically active ligands

Complexes derived from ampicillin (L1) and amoxicillin (L2) with (Mg(II), Ca(II), Zn(II), Cu(II), Ni(II), Co(II), Ce(III), Nd(III), UO₂(VI), Th(IV)) were prepared and characterized by elemental analysis, electrical conductivity measurements, magnetic susceptibility, IR, UV/Vis, and thermogravimetry. The formed complexes can be formulated as (ML(H₂O)₃(NO₃) _n ) except for Ce(III) which gave (CeL(H₂O)₃(Cl)₂). The ¹H NMR spectra of the Zn(II) complexes are compared to spectra of the ligands. The shift (δ) gave information about the chelating center of the ligands. The ligands and the synthesized complexes, derived from some alkali earth and transition metal ions, were tested as antibacterial reagents. The formed complexes had enhanced activity.     

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.     

Synthesis of some new biologically active coumarin derivatives

The reaction of 4-hydroxycoumarin in toluene with a variety of aromatic binucleophilic compounds has been studied. 3-(Dimethylaminomethylene)chromane-2,4-dione was used as a key intermediate for the preparation of bis[N-(4-oxocoumarinylmethylene)]-1,4-diamines. Alternative synthetic procedures and antibacterial activity data of some of the new compounds are given. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 361–366, March, 2006.     

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.     

Ultrasonic-promoted three-component synthesis of some biologically active 1,2,5,6-tetrahydropyrimidines

Multicomponent reactions and organic synthesis with ultrasonic activation have been used as key methods for the synthesis of tetrahydropyrimidine derivatives. The three-component condensation of 1,3-diarylprop-2-en-1-one with ammonia and aldehydes/acetone or N-substituted gamma-pyridones under ultrasonic irradiation was developed as a rapid and efficient solution-phase method for the high-yielding preparation of 2-aryl(hetaryl)-4,6-diaryl-1,2,5,6-tetrahydropyrimidines and 2,4-diaryl-1,5,9-triazaspiro[5.5]undec-1-enes. The described synthetic protocol provides rapid access to novel and diversely substituted tetrahydropyrimidines libraries. The simple, primary biological screening showed 98% of inhibitory activity against Mycobacterium tuberculosis for one of tetrahydropyrimidines synthesized.     

Search for biologically active substances among heteroaromatic compounds (review)

Research on the synthesis and investigation of the chemical and spectral characteristics of heterocyclic compounds carried out in the department of chemistry Osmania University (Hyderabad, Andra Pradesh, India) is examined in the review.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–310, March, 1977.     

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.     

The mass spectrometric fragmentation patterns of some biologically active 1,3,4-thiadiazoles

Mass spectra of some twelve derivatives of 1,3,4-thiadiazole are reported. The fragmentation scheme of the 1,3,4-thiadiazole ring is specific and indicative as to the structure. Derivatives of 5-phenyl-1,3,4-thiadiazoles show rearrangement to isothiocyanates.     

Determination of biologically active substances in roasted coffees using a diode-array HPLC system.

We studied the simultaneous quantitative analysis of biologically active substances, such as nicotinic acid, trigonelline, caffeine, qunolinic acid and tannic acid and pyrogallic acid, in several roasted coffees by an HPLC/diode-array system with a home-made sol-gel and ODS-2 columns. A simple method for simultaneous quantitative analysis of biologically active substances in the coffee brew became feasible by an HPLC/diode-array system with a sol-gel column at a single wavelength of 210 nm. The most efficient condition of the Rs value was above 1.05 when two sol-gel columns were connected. In addition, the elution behavior of nicotinic acid in brew extracted from commercially available coffee beans suggests the thermal decomposition process during roasting, and indicated the maximum value for full city roasted coffee.     

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.     

Thermal studies on some group VIII complexes with biologically active ligands

The mode of decomposition of complexes involving biologically important ligands such as thiouracil and xanthine coordinated to some group VIII metals has been studies by thermogravimetry. The results show that the complex tris-(dithiouracil) trichlororhodium(III) is monomeric and not polymeric as suggested previously. The decomposition behavior of the complex indicates that after the initial loss of a ligand molecule to form a four-coordinate complex, further ligand removal takes place in one sharp step. In the case of the complexes bis-(3-methylxanthine) diammineplatinum(II) and bis-(9-methylxanthine) diamminepalladium(II), ammonia comes off first, followed by rapid loss of the remaining xanthine ligands. Moreover, the activation energy determined for the main decomposition step suggests that the breakdown of the xanthine ligand involves the initial cleavage of the pyrimidine moiety, followed closely by loss of the remaining imidazole portion.

---

Zusammenfassung Die Art der Zersetzung von Komplexen einiger Metalle der VIII. Gruppe mit biologisch wichtigen Liganden, wie Thiouracil and Xanthin, wurde thermogravimetrisch untersucht. Die Ergebnisse zeigen, daß der Komplex Tris-(dithiouracil) trichlororhodium(III) monomer und nicht — wie früher vermutet — polymer ist. Das Zersetzungsverhalten des Komplexes zeigt, daß nach dem zu einem tetrakoordinierten Komplex führenden Verlust eines Ligandmoleküls die Abgabe eines weiteren Liganden in einem scharfen Schritt erfolgt. Im Falle der Komplexe Bis-(3-methylxanthin) diamminplatin(II) und Bis-(9-methylxanthin) diamminpalladium(II) erfolgt zunächst eine Abspaltung von Ammoniak, der ein schneller Verlust der verbleibenden Xanthinliganden folgt. Die für die Hauptzersetzungsreaktion bestimmte Aktivierungsenergie läßt vermuten, daß der Abbau der Xanthinliganden über eine Spaltung des Pyrimidinteils verläuft, der schnell die Abgabe des verbleibenden Imidazolteils folgt.

---

, , VIII . , -() (III) , , . - , . - (3-) (II) -(9 -) - (II) -(II) , . , , , , .

     

An examination of some active organometallic substances for ion-selective electrodes

Examinations of a number of possible electroactive substances for use in both liquid membrane and solid-state ion-selective electrodes were carried out. Liquid membrane electrodes incorporating organometallic salts of lead and thallium were considered as constituents of sulphate, chromate, carbonate and nitrate responsive sensors. No practically useful device was, however, found. Several electrically semiconducting metal-phthalocyanines, metal-tetracyanoethylene (TCNE) polymers and metal-coordination polymers were also synthesized and investigated with solid-state electrode constructional techniques. Metal-phthalocyanine electrodes were found to be responsive to anions rather than to cations and some anion selectivity was observed. Metal-TCNE polymer electrodes showed response to metal ions identical with those contained in the polymer, and some good selectivities, operational activity ranges and response times were found. Electrodes made from coordination polymers incorporating copper showed a limited response to copper ions whilst inclusion of cadmium and iron(III) in the polymer matrix produced an electrode with anion reponse and slight anion selectivity.     

Potencies of ligand-exchange capillary electrophoresis in the determination of biologically active compounds

The analytical potencies of ligand-exchange capillary electrophoresis (LECE) in regard to the determination of bioactive substances are discussed. As it is shown, complexation with copper(II) in the electrophoretic determination with UV detection makes possible the determination of amino acids, amines, and sugars, which do not absorb in the UV region, with the limits of detection 5–10 mg/L, and reduce the detection limits of the absorbing analytes, such as tryptophane, tyrosine, and histamine by 2–3 times. Prospects for using online preconcentration for the reduction of c _min are shown on an example of aliphatic amino acids, i.e., thirtyfold preconcentration is attained. LECE is shown to be applicable to the simultaneous determination of glucose, Na(⁺), and K(⁺) in human blood serum. Also versions of ligand-exchange capillary electrophoresis with direct UV detection and capillary zone electrophoresis with indirect one are compared in terms of efficiency, time of analysis, and limit of detection. The potencies of the LECE method are compared with those of ligand-exchange chromatography.