ABSTRACT
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.
ABSTRACT
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.
