Olesya Voronova

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.

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.

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.

Voltammetric determination of cholesterol in human blood serum

Cholesterol has a number of important functions in a human body. The disorders of cholesterol biosynthesis increase the risk of the development of cardiovascular diseases and worsens the function of the immune system. This study is devoted to the development of a method for determining the concentration of cholesterol in blood serum using voltammetry. We selected the following working conditions for the determination of cholesterol: a phosphate buffer solution with pH 6.86 was a supporting electrolyte; potential sweep rate was W = 30 mV/s; and recording was carried out in the constant-current mode. An organomodified electrode was used as a working electrode. The peak was observed at +0.98 V. The dependence of the electrooxidation current of cholesterol on its concentration was linear in the range of 0.1–50 μM with a limit of detection of 0.01 μM. The results of the determination of cholesterol in blood serum by voltammetry were compared to those obtained by the fluorimetric method.

Voltammetric Determination of Carmoisine in Soft Drinks

A voltammetric study of the electrochemical behavior of red food azo dye Carmoisine on a glassy carbon electrode (GCE) is performed. The influence of various factors on the cathode signal of the dye is shown: pH and values of accumulation time and potential sweep rate. The operating conditions of Carmoisine identification in model media are selected: pH = 1.65, Eacc = –0.1 V, tacc = 10 s, W = 100 mV/s. A linear dependence of the electrolytic reduction current of the dye on its concentration at –0.15 V is observed within 0.05–0.5 mg/L; detection limit of Carmoisine is 0.02 mg/L. A comparative determination of Carmoisine in soft drinks is performed by voltammetric and spectrophotometric methods.

Antioxidant and immunotropic properties of some lithium salts

Article history: Objective: The antioxidant activity and immuno-tropic effects of lithium glutamate, lithium salicylate, lithium benzoate and lithium lactate have been investigated in this work, as a base for new psychotropic medicines. Methods: The antioxidant properties were studied by the voltammetric method. Phagocytic activity of neutrophilic leucocytes and the reaction of blastic transformation of lymphocytes were used as test for assessments of influence of the lithium compounds on the immune cells of human blood. Results: It was revealed absence of toxic action on human blood cells for all tested substances. Lithium benzoate showed the most significant stimulating influence on lymphocytes. Glutamate and benzoate lithium expressed scavenging activity vs oxygen radicals. Salicylate and benzoate lithium revealed significant phagocytosis stimulation effects. Conclusion: Investigated lithium salts expressed antioxidant activity and immunotropic effects, all investigated substance are of interest in medical application for mental diseases and comorbid pathology treatment.

Characterization of a Novel Dioxomolybdenum Complex by Cyclic Voltammetry

Metalloenzymes that carry a pterin-based molybdenum cofactor in their center catalyze numerous reactions in the human body and play a crucial role in its metabolism. Specifically, these enzymes promote redox reactions and oxygen transport in the body. Their absence may cause many problems leading to disability or even death in early childhood. Therefore, model compounds need to be synthesized and analyzed to investigate the reactivity, redox potential, and geometry of these cofactors. This study focused on electrode processes and determined the redox potentials of the new bis-(4-mercapto-5-(p-tolyl)-3H-1,2-dithiole-3-thione)-dioxomolybdenum complex by cyclic voltammetry. The 4-mercapto-5-(p-tolyl)-3H-1,2-dithiole-3-thione ligand underwent irreversible oxidation and reduction at thiol and thione functional groups. The new dioxomolybdenum complex showed a quasi-reversible two-stage electrode process.