Antioxidant Properties of New Phenothiazine Derivatives.

Phenothiazine and its derivatives have a number of properties that contribute to their wider practical use in the production of biologically active substances, drugs, dyes, etc. Therefore, the synthesis and study of new compounds is of great relevance. The aim of this work was to investigate the antioxidant activity of a number of new phenothiazine derivatives. The patterns of electroreduction of oxygen and its radicals in the presence of phenothiazine derivatives in aqueous ethanol media were studied by voltammetry. The influence of various factors on antioxidant activity was considered by the methods of experiment planning. The optimal conditions for the manifestation of the antioxidant activity of phenothiazine derivatives have been found, which seems to be relevant since it opens up new possibilities for their further use as complex preparations with antioxidant activity, including in psychiatric practice.

Preparation and Investigation of Silver Nanoparticle⁻Antibody Bioconjugates for Electrochemical Immunoassay of Tick-Borne Encephalitis.

A new simple electrochemical immunosensor approach for the determination of antibodies to tick-borne encephalitis virus (TBEV) in immunological products was developed and tested. The assay is performed by detecting the silver reduction signal in the bioconjugates with antibodies (Ab@AgNP). Here, signal is read by cathodic linear sweep voltammetry (CLSV) through the detection of silver chloride reduction on a gold-carbon composite electrode (GCCE). Covalent immobilization of the antigen on the electrode surface was performed after thiolation and glutarization of the GCCE. Specific attention has been paid to the selection of conditions for stabilizing both the silver nanoparticles and their Ab@AgNP. A simple flocculation test with NaCl was used to select the concentration of antibodies, and the additional stabilizer bovine serum albumin (BSA) was used for Ab@AgNP preparation. The antibodies to TBEV were quantified in the range from 50 IU·mL-1 to 1600 IU·mL-1, with a detection limit of 50 IU·mL-1. The coefficient of determination (r2) is 0.989. The electrochemical immunosensor was successfully applied to check the quality of immunological products containing IgG antibodies to TBEV. The present work paves the path for a novel method for monitoring TBEV in biological fluids.

Lithium Salts of Krebs Cycle Substrates as Potential Normothymic Antioxidant Agents.

OBJECTIVE: Aim of the present work was to study the antioxidant properties of lithium salts of Krebs cycle substrates and their influence on immune cells. Lithium is a well-known and widely used mood stabilizer. These lithium-based substances have a lot of potential properties because of the anionic component of the Krebs cycle substrates, which take part in basic intracellular biochemical process. MATERIALS AND METHODS: Lithium salts of fumarate, pyruvate, malate, succinate, and citrate (as reference drug) were investigated in this study as antioxidants and immunomodulators. The antioxidant properties were studied by the voltammetry method, which evaluates oxygen radical scavenging capacity of lithium substances. Influence of the lithium compounds on the immune cells of human blood was indicated by the reaction of blast transformation of lymphocytes. RESULTS: All tested substances and their mixes possessed antioxidant properties, more expressed in maximal therapeutic concentration. Lithium compounds showed no toxic influence on human blood immune cells and caused no significant changes in both spontaneous and stimulated proliferation. CONCLUSION: The results allow considering lithium salts of Krebs cycle substrates as potential normothymic agents (mood stabilizer) with antioxidant properties and low toxicity.

Electrochemical Oxidability of Antioxidants: Synergism and Antagonism in Mixes.

AIMS: To investigate electrochemical oxidability of antioxidants to reveal synergistic and antagonistic effects in mixes. MATERIALS AND METHODS: Electrochemical oxidability of some widely used antioxidants, including uric acid, glutathione, trolox, ascorbic acid, gallic acid, Mexidol, and potassium fenozan, was investigated by the amperometric approach. RESULTS: All obtained electrochemical oxidability values correlate well with antioxidant activity parameters of the same compounds measured by other methods. The measurements of the electrochemical oxidability for binary mixes of substances were tested to reveal any synergistic actions. The experimental results and calculated values overlap for various combinations of tested mixes. It testifies to the absence of interaction between them (both synergism and antagonism) in the oxidation process. CONCLUSIONS: The constants of oxidation were defined for different antioxidants and mixes by amperometric approach. Most mixes of probed compounds revealed absence of interaction between them in oxidation process. In some cases (mainly with glutathione and ascorbic acid), antagonism takes place, deteriorating effects of their joint application. Apparently, a partial reduction of glutathione by ascorbic acid leads to excess of the measured value over calculated value.

Comparative investigation of antioxidant activity of human serum blood by amperometric, voltammetric and chemiluminescent methods.

INTRODUCTION: A blood test can provide important information about the functional state of the antioxidant system. Malfunction of this system increases the concentration of free radicals and can cause oxidative stress. A difficulty in assessing oxidative stress is the lack of a universal method for determining the antioxidant activity (AOA) of blood components, because of their different nature. MATERIAL AND METHODS: The objects of investigation were sera of 30 male patients with a diagnosis of alcohol dependence syndrome and healthy donors. Comparative investigation of total antioxidant activity (TAA) of human serum blood was carried out by voltammetric (VA), amperometric (AM) and chemiluminescent (HL) methods. RESULTS: All applied methods revealed that serum TAA of the patients with alcoholism is lower than TAA of healthy donors (control group); according to amperometric method the average value of serum TAA was 850 ±210 nA × s, and 660 ±150 nA × s for healthy donors and alcoholics respectively (p < 0.05). Similar trend was revealed by chemiluminescence and voltammetry methods. The results confirm that thiol compounds make a significant contribution to the antioxidant activity of serum. The average thiol concentrations were 0.94 ±0.34 mmol/l and 1.21 ±0.36 mmol/l (p < 0.05) for alcoholics and healthy donors respectively. Decreasing thiol concentration in blood of alcoholics leads to depletion of antioxidant systems of blood. However, the differences between the results of AM, VA and HL methods were significant, because they reflected different aspects of antioxidant activity. CONCLUSIONS: For objective assessment of antioxidant activity of biological objects, we suggest using methods based on different model systems.

Study of total antioxidant activity of human serum blood in the pathology of alcoholism.

The total antioxidant activity (TAA) of human serum blood of patients suffering from alcoholism was tested by cathode voltammetry with a model process of oxygen electroreduction. A known spectrophotometrical method was used for comparison. As results the total antioxidant activity of serum blood of patients with alcoholism was estimated by voltammetry during therapy in hospital. It was shown the TAA of serum blood of patients in pathology before and after treatment is lower than that one of healthy people. However, during the process of 10 days of alcoholism treatment the TAA coefficient increases. The relationship between the coefficient of total antioxidant activity of human serum blood and the stage of treatment was detected.