scholarly journals COMPARISON OF L-ASPARAGINE INTERACTIONS WITH PYRIDINE DERIVATIVES, PYRIDOXAL- 5'-PHOSPHATE AND PYRIDOXINE, IN AQUEOUS SOLUTIONS: THERMODYNAMIC ASPECTS

2021 ◽  
Vol 64 (5) ◽  
pp. 12-18
Author(s):  
Elena Yu. Tyunina ◽  
Olga N. Krutova ◽  
Alexandr I. Lytkin
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Aspartic Acid ◽  
Acid Amide ◽  
The Body ◽  
Biologically Active ◽  
Stable Complex ◽  
Thermochemical Study ◽  
Oh Groups ◽  
Heat Effects

Interactions of proteins with various biologically active substances (hormones, drugs, enzymes, etc.) underlie many biochemical processes in the body. As part of the long-term task to studying various aspects of the interaction between model protein compounds and heterocyclic compounds that are into the structure of many enzymes and drugs, the thermochemical study of aqueous solutions containing aspartic acid amide (L-asparagine) and peridoxal-5¢-phosphate was carried out. Calorimetric measurements of the enthalpy of L-asparagine dissolution in an aqueous solution with pyridoxal-5¢-phosphate additives were performed on an ampoule-type isoperibolic dissolution calorimeter at 298.15 K. The error of measuring single heat effects was below 0.2%. The relative combined uncertainty in the measurements of the enthalpies of dissolution was not more than 0.7%. Based on the obtained experimental data and the using the HEAT computer program, the binding constants and thermodynamic parameters (lgK, ΔcG, ΔcH, ΔcS) of the complex formation between the reagents under study were calculated. A comparison of the affinity of amino acids to interaction with pyridoxal-5¢-phosphate and pyridoxine was carried out. The features of their behavior in an aqueous solution are revealed. It is shown that the interaction of L-asparagine with pyridoxine leads to the formation of a more stable complex than with peridoxal-5¢-phosphate. This fact may be explained in terms of a bulky phosphate group that hinders apparently the interaction of POP with aspartic acid amide. In addition, the peridoxal-5¢-phosphate molecule contains intramolecular hydrogen bonds between aldehyde CHO and phenolic OH groups, which must be destroyed by the interaction of peridoxal-5' - phosphate with an amino acid, which requires additional energy expenses. Thus, the selectivity of the interaction and the stability of the formed complexes are mainly regulated by the factors of structural and energy complementarity.

Inactivation of biologically active N-methyl-N-nitroso compounds in aqueous solution: effect of various conditions of pH and illumination

1968 ◽  
Vol 46 (8) ◽  
pp. 807-811 ◽  
Author(s):  
D. R. McCalla ◽  
Antoon Reuvers ◽  
Ruth Kitai
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Low Ph ◽  
Biologically Active ◽  
The Other ◽  
Nitroso Compounds ◽  
Breakdown Rates ◽  
Dilute Aqueous Solutions

The rates of decomposition of N-methyl-N′-nitro-N-nitrosoguanidine (NG), N-methyl-N-nitroso-p-toluenesulfonamide (MNTS), N-methyl-N-nitrosourea, and N-methyl-N-nitrosourethane in dilute aqueous solutions at pH levels ranging from 2 to 9 are tabulated. There are considerable differences in the breakdown rates of these compounds. At low pH, MNTS is destroyed several times faster than any of the other compounds, while at pH 7, MNTS is about 100 times as stable as methylnitrosourea. Rates of photochemical destruction of NG and MNTS are also given. Some of the breakdown products have been identified. These data are used to provide tentative explanations for some apparently anomalous biological results.

scholarly journals EFFECT OF MODIFICATION OF THE EXTRACTION TECHNIQUE OF THE SUBSTANCE IN A SOXHLET FOR CONTENT OF FATTY ACIDS

2018 ◽  
Vol 14 (1-2) ◽  
pp. 18-23 ◽  
Author(s):  
L.V. Natrus ◽  
O.I. Kryvosheyeva ◽  
G.R. Lamazyan ◽  
T.S. Bruzgina
Keyword(s):  
Aqueous Solution ◽  
Processing Time ◽  
Raw Materials ◽  
The Body ◽  
Biologically Active ◽  
Gas Liquid Chromatography ◽  
Citrullus Colocynthis ◽  
Plant Materials ◽  
Dry Extract ◽  
Soxhlet Apparatus

Relevance. The search for new forms of herbal medicine is an important area of modern biotechnology, pharmacology and pharmacy. More and more attention is paid to the development of extracts from plant materials, since the extraction products provide the maximum content of biologically active substances, which increases the rationality of their use, due to the accuracy of dosing, the therapeutic effect is increased, the period of use increases and storage conditions are simplified. The extraction of the fruit mixture of Citrullus сolocynthis in the Soxhlet apparatus was modified by reducing the procedure time 5-10 times and improving the processing of raw materials by using a press at the same time and increasing the temperature, or even by modifying the apparatus. Objective: to study the composition of FA in an aqueous solution of the dry extract of Citrullus сolocynthis when modifying the extraction mixture in the Soxhlet apparatus by increasing the temperature and technological reduction of processing time. Materials and methods. We carried out the determination and comparison of the composition of FA’s by gas-liquid chromatography of all parts of the fruit of Citrullus сolocynthis and in an aqueous solution of its dry extract with various concentrations of the substance. Results. Chromatographic analysis showed that all parts of the fetus Citrullus colocynthis are promising sources of saturated and unsaturated FA. In all parts of the fruit of Citrullus colocynthis, linoleic acid prevails in quantitative content. The modification of the extraction of the mixture in the Soxhlet apparatus by increasing the temperature and technological reduction in the processing time of the raw materials led to the production of a substance with a new composition and FA content. The ratio of unsaturated / saturated FA in the resulting dry extract is 5 times greater than the similar ratio separately in seeds, pulp and shell. At the same time, the distribution of separate unsaturated and polyunsaturated FA’s in the dry extract solution is fairly uniform. The relative amount of linoleic FA in the dry extract was smaller, and the linolenic FA was greater than in the seeds and pulp of the fruit. Conclusions. Modifying the extraction of the mixture in the Soxhlet apparatus by increasing the temperature and technological reduction of the processing time did not lead to complete degreasing of the substrate and allowed to obtain a dry extract of Citrullus solvent with content of microdoses of the FA, their balanced (uniform) in amount, and predominance of 5 times the amount of unsaturated polyunsaturated FA over the amount of saturated. We assume that such a redistribution of FA, and especially their micro doses, can be the basis for creating medicines with more effective effects on the body.

scholarly journals EFFECT OF MODIFICATION OF THE EXTRACTION TECHNIQUE OF THE SUBSTANCE IN A SOXHLET FOR CONTENT OF FATTY ACIDS

2018 ◽  
Vol 14 (1-2) ◽  
pp. 18-23
Author(s):  
L.V. Natrus ◽  
O.I. Kryvosheyeva ◽  
G.R. Lamazyan ◽  
T.S. Bruzgina
Keyword(s):  
Aqueous Solution ◽  
Processing Time ◽  
Raw Materials ◽  
The Body ◽  
Biologically Active ◽  
Gas Liquid Chromatography ◽  
Citrullus Colocynthis ◽  
Plant Materials ◽  
Dry Extract ◽  
Soxhlet Apparatus

Relevance. The search for new forms of herbal medicine is an important area of modern biotechnology, pharmacology and pharmacy. More and more attention is paid to the development of extracts from plant materials, since the extraction products provide the maximum content of biologically active substances, which increases the rationality of their use, due to the accuracy of dosing, the therapeutic effect is increased, the period of use increases and storage conditions are simplified. The extraction of the fruit mixture of Citrullus сolocynthis in the Soxhlet apparatus was modified by reducing the procedure time 5-10 times and improving the processing of raw materials by using a press at the same time and increasing the temperature, or even by modifying the apparatus. Objective: to study the composition of FA in an aqueous solution of the dry extract of Citrullus сolocynthis when modifying the extraction mixture in the Soxhlet apparatus by increasing the temperature and technological reduction of processing time. Materials and methods. We carried out the determination and comparison of the composition of FA’s by gas-liquid chromatography of all parts of the fruit of Citrullus сolocynthis and in an aqueous solution of its dry extract with various concentrations of the substance. Results. Chromatographic analysis showed that all parts of the fetus Citrullus colocynthis are promising sources of saturated and unsaturated FA. In all parts of the fruit of Citrullus colocynthis, linoleic acid prevails in quantitative content. The modification of the extraction of the mixture in the Soxhlet apparatus by increasing the temperature and technological reduction in the processing time of the raw materials led to the production of a substance with a new composition and FA content. The ratio of unsaturated / saturated FA in the resulting dry extract is 5 times greater than the similar ratio separately in seeds, pulp and shell. At the same time, the distribution of separate unsaturated and polyunsaturated FA’s in the dry extract solution is fairly uniform. The relative amount of linoleic FA in the dry extract was smaller, and the linolenic FA was greater than in the seeds and pulp of the fruit. Conclusions. Modifying the extraction of the mixture in the Soxhlet apparatus by increasing the temperature and technological reduction of the processing time did not lead to complete degreasing of the substrate and allowed to obtain a dry extract of Citrullus solvent with content of microdoses of the FA, their balanced (uniform) in amount, and predominance of 5 times the amount of unsaturated polyunsaturated FA over the amount of saturated. We assume that such a redistribution of FA, and especially their micro doses, can be the basis for creating medicines with more effective effects on the body.

scholarly journals Synthesis and stability of the dirhenium(III) cluster compounds with isoleucine, serine and proline in aqueous solutions

2020 ◽  
pp. 38-43
Author(s):  
Y.V. Husak ◽  
◽  
A.A. Ovcharenko ◽  
A.A. Golichenko ◽  
A.V. Shtemenko ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Electronic Absorption Spectra ◽  
Complex Compounds ◽  
Biologically Active ◽  
Cluster Compounds ◽  
Imino Group ◽  
Bending Vibrations ◽  
Oh Groups ◽  
Carboxylate Groups ◽  
The Stability

The previously developed methods for the synthesis of cis-tetrachlorodi--carboxylates of dirhenium(III) were modified, due to which the derivatives of Re26+ with proteinogenic amino acids (AA) isoleucine, serine and proline were synthesized for the first time. The composition and structure of these substances with the general formula cis-[Re2(АA)2Cl4(CH3CN)2]Cl2 were confirmed by elemental analysis, electron adsorption and IR spectroscopy. The presence of a characteristic peak, which corresponds to the *-electronic transition of the Re–Re quadruple bond for compounds with the cis-arrangement of two bridging-coordinated carboxylate groups in the ligand environment of the Re26+ cluster, was showed by using the data on the electronic absorption spectra of solutions of the synthesized compounds. The IR spectrum contains an intense, weakly split band in the region of 1466–1458 cm–1, which is attributed to the s(CO) coordinated carboxyl group and indicates its bridging coordination to the binuclear Re26+ fragment. The spectra exhibited the presence of bands of stretching (NH3+) and bending vibrations (NH3+) of protonated amino groups in complex compounds of isoleucine and serine and the presence of bands of stretching (NH2+) and bending vibrations (NH2+) of the protonated imino group of proline. The stability of the prepared complex compounds in aqueous solutions was investigated. It is shown that the hydrolysis of the synthesized substances occurs within 9–14 days with a decrease in the pH of the reaction solution due to a gradual replacement of labile chloride ligands by OH–-groups at the first stages of interaction with water. The resistance to hydrolysis is an important parameter of biologically active substances; the determination of the resistance to hydrolysis will expand understanding of the possible mechanisms of their specific biological activity.

Neutral Lipids of Oats Fruit (Avena Sativa L.)

2020 ◽  
Vol 9 (4) ◽  
pp. 40-43
Author(s):  
N. K. Yuldasheva ◽  
S. D. Gusakova ◽  
D. Kh. Nurullaeva ◽  
N. T. Farmanova ◽  
R. P. Zakirova ◽  
...  
Keyword(s):  
Avena Sativa ◽  
Neutral Lipids ◽  
The Body ◽  
Biologically Active ◽  
Absorption Bands ◽  
Vital Functions ◽  
The Republic ◽  
Living Organisms ◽  
Main Components ◽  
Active Substances

Introduction. Lipids are a widespread group of biologically active substances in nature, making up the bulk of the organic substances of all living organisms. They accumulate in plants in seeds, as well as in fruits and perform a number of vital functions: they are the main components of cell membranes and the energy reserve for the body.Aim. Study of neutral lipids of sown oats (Avena sativa L.).Materials and methods. The objects of the study were fruits (grains) of oats of the sown variety "Tashkent 1," harvested in the Republic of Uzbekistan. Results and discussions. Neutral lipids of oat grains have been found to contain 13 fatty acids with a predominance of the sum of oleic, linolenic and linoleic acids. The total degree of unsaturation was almost 78%. Absorption bands characteristic of these substances were observed in the IR spectrum of MEGC.Conclusion. According to the results of the NL analysis, oat grains consisted of triacylglycerides and free LCDs, which were accompanied by hydrocarbons, phytosterols, triterpenoids and tocopherols.

Fast Method for the Determination of Residual Solvents in Radiopharmaceutical Products

2017 ◽  
Vol 68 (4) ◽  
pp. 666-670 ◽  
Author(s):  
Mirela Mihon ◽  
Catalin Stelian Tuta ◽  
Alina Catrinel Ion ◽  
Dana Niculae ◽  
Vasile Lavric
Keyword(s):  
Gas Chromatography ◽  
Control Method ◽  
Limit Of Detection ◽  
The Body ◽  
Biologically Active ◽  
Injection Technique ◽  
Fast Method ◽  
Residual Solvent ◽  
Residual Solvents

The aim of this work was the development and validation of a fast analytical method to determine the residual solvents content in radiopharmaceuticals such as: 18F-Fluorodeoxyglucose (18F-FDG), 18F-Fluoroestradiol (18F-FES), 18F-Fluorothymidine (18F-FLT),18F-Fluoromisonidazole (18F-FMISO). Radiopharmaceuticals are radioactive preparations for medical purposes used in nuclear medicine as tracers in diagnostic imaging and treatment of certain diseases. Positron Emission Tomography (PET) is a medical imaging technique that consists in introducing into the body of a small amount of a biologically active chemical compound labelled with a short lived positron-emitting radioisotope (18F, 11C, 68Ga). Residual solvents are critical impurities in radiopharmaceuticals that can affect labelling, stability and physicochemical properties of drugs. Therefore, the determination of these solvents is essential for quality control of radiopharmaceuticals. Validation of the control method for residual solvents by gas chromatography is referred by the European Pharmacopoeia using a special injection technique (head space). The parameters of the method, which comply with International Conference on Harmonization guidelines, are: accuracy, precision, linearity, limit of detection, limit of quantification and robustness. The proposed method (direct gas chromatography injection) proved to be linear, precise, accurate and robust. Good linearity was achieved for all the solvents and correlation coefficients (R2) for each residual solvent were found more than 0.99.

Nutrients Mediate Bioavailability and Turnover of Proteins in Mammals

2019 ◽  
Vol 20 (7) ◽  
pp. 661-665
Author(s):  
Cunxi Nie ◽  
Fei Xie ◽  
Ning Ma ◽  
Yueyu Bai ◽  
Wenju Zhang ◽  
...  
Keyword(s):  
The Body ◽  
Biologically Active ◽  
Nitrogen Excretion ◽  
Dietary Proteins ◽  
Restricted Diet ◽  
Nutritional Interventions ◽  
Body Tissues ◽  
Utilization Of Protein ◽  
High Level ◽  
Protein Restricted Diet

As a major component of biologically active compounds in the body, proteins contribute to the synthesis of body tissues for the renewal and growth of the body. The high level of dietary protein and the imbalance of amino acid (AA) composition in mammals result in metabolic disorders, inefficient utilization of protein resources and increased nitrogen excretion. Fortunately, nutritional interventions can be an effective way of attenuating the nitrogen excretion and increasing protein utilization, which include, but are not limited to, formulating the AA balance and protein-restricted diet supplementing with essential AAs, and adding probiotics in the diet. This review highlights recent advances in the turnover of dietary proteins and mammal’s metabolism for health, in order to improve protein bioavailability through nutritional approach.

Effect of thermal history of aqueous solutions of KCl on the metastable zone width

1984 ◽  
Vol 49 (3) ◽  
pp. 559-569 ◽  
Author(s):  
Jaroslav Nývlt
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Thermal History ◽  
Equilibrium Solubility ◽  
Metastable Zone Width ◽  
Zone Width ◽  
Preceding Experiment ◽  
History Of ◽  
Metastable Zone ◽  
The Given

The metastable zone width of an aqueous solution of KCI was measured as a function of the time and temperature of overheating above the equilibrium solubility temperature. It has been found that when the experiments follow close upon one another, the parameters of the preceding experiment affect the results of the experiment to follow.The results are interpreted in terms of hypotheses advanced in the literature to account for the effect of thermal history of solution. The plausibility and applicability of these hypotheses are assessed for the given cause of aqueous solution of a well soluble electrolyte.

scholarly journals I. Thermo-electric behaviour of aqueous solutions with mercurial electrodes

1879 ◽  
Vol 29 (196-199) ◽  
pp. 472-482 ◽  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Internal Diameter ◽  
Thermo Electric ◽  
Thin Glass ◽  
Mercury Surface

In order to investigate this subject, I devised and constructed the following apparatus :—A and B are two thin glass basins, 81 millims. internal diameter (= 5,153 sq. millims. of mercury surface), and 6·0 centims. deep; each containing a layer of mercury about 1·0 centim. deep, covered by a layer, about 3 centims. deep, of the aqueous solution to be examined.

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

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