Exploration of the global antioxidant capacity of the stratum corneum by cyclic voltammetry (original) (raw)

Evaluation of antioxidant properties of dermocosmetic creams by direct electrochemical measurements

International Journal of Cosmetic Science, 2005

Cyclic voltammetry and linear sweep voltammetry were preliminarily used in order to evaluate the global antioxidant properties of dermocosmetic creams. Experiments were performed by introducing electrodes directly into the creams without any pretreatment of the samples. Current-potential curves showed significant anodic current depending on the antioxidant-containing cream studied. In comparison, little amperometric response was recorded with an antioxidant-free cream base. Aqueous solutions of the corresponding antioxidants showed analogous anodic waves and similar peak potentials. A correlation between the global anodic peak and the presence of the antioxidant species in the cream was made with eleven skin creams, attesting to the reliability of the method. Among the tested electrode materials, platinum gave the best results in terms of electrochemical kinetics and measurement precision (current peak standard deviation less than 5%). Exposure of a depilatory cream to oxidizing agents (e.g., hydrogen peroxide, air, or light) caused a decrease in peak current as expected. This methodology enabled us to evaluate the evolution of the total antioxidant capacity under oxidative stress and gives encouragement to further development of a voltammetric method to quantify cream antioxidant power.

Noninvasive Potentiometric Method of Determination of Skin Oxidant/Antioxidant Activity

IEEE Sensors Journal, 2012

The article proposes theoretical and experimental justification for using potentiometry as a new noninvasive method of evaluating antio xidant/oxidant state (oxidative stress) of a skin. Since the inductor of o xidative stress is an overall deficit of electrons accessible to cells, electrochemical methods of evaluating this parameter are naturally considered as fully corresponding with the nature of the phenomenon. A mathematical model is proposed that describes the processes determining analytical signals in the 'skin-gel-electrode' system. The signal occurs as a result of interaction between antioxidants/oxidants diffusing from the epidermis of the skin into the gel and the mediator system o xidised or reduced component introduced into the gel. The in formation source with regard to AOA/OA (antio xidant/oxidant activity) is the electrode potential shift. It occurs when the gel co mes into contact with the skin. The series of potential determining substance-time dependences was obtained as a result of numerical simu lation and experiment. Typical relationships between different parameters (chemical reaction rate, gel layer thickness, time) and concentration equal to antio xidant or o xidant activity, (A OA or OA) were found. An agreement between the calculated and experimental data was obtained. Findings analysis enables to forecast features of the experimental relations and provided an opportunity to choose experimental conditions ensuring the most reliable results.

The use of cyclic voltammetry for the evaluation of antioxidant capacity

Bio-assays for oxidative …, 2001

Low-molecular weight antioxidants (LMWAs) play a major role in protecting biological systems against reactive oxygen-derived species and reflect the antioxidant capacity of the system. Cyclic voltammetry (CV), shown to be convenient methodology, has been validated for quantitation of the LMWA capacity of blood plasma, tissue homogenates, and plant extracts. Analysis of the CV tracing yields the values of (i) the biological oxidation potential, E and E 1/2 , which relate to the nature of the specific molecule(s); (ii) the intensity (Ia) of the anodic current; and (iii) the area of the anodic wave (S). Both Ia and S relate to the concentration of the molecule(s). LMWA components of human plasma and animal tissues were identified and further validated by reconstruction of the CV tracing and by high-performance liquid chromatography-electrochemical detection. To reflect the oxidative stress status, the use of an additional parameter, R, has been proposed. R represents the level (%) of oxidized ascorbate (compared with total ascorbate) and is measured by high-performance liquid chromatography-electrochemical detection. All these parameters were monitored in healthy human subjects as well as in chronic (diabetes mellitus) and acute care patients (subjected to total body irradiation before bone marrow transplantation). The electroanalytical methodologies presented here could be widely employed for rapid evaluation of the status of subjects (in health and disease) for monitoring of their response to treatment and/or nutritional supplementation as well as for screening of specific populations.

Optimized Potentiometric Assay for Non-invasive Investigation of Skin Antioxidant Activity

Electroanalysis, 2018

The paper presents a new variant of noninvasive potentiometric method for determination of human skin antioxidant activity (AOA). The use of a porous cellulose acetate membrane as the carrier for reagent solution (potassium hexacyanoferrate (III)) is presented. The increase of reagent shelf life, improvement the reproducibility of the results (during the day Sr 0.08, interday Sr 0.13) in comparison with previously described variant is demonstrated. It was shown that the components of the skin hydrolipid mantle and pH do not affect the potentiometric signal. The values of skin AOA determined by the developed method lie in the range 20-4000 mM-eq. Recovery is R average = 99 %. The skin of healthy people was studied by the developed method. The obtained results indicate the prospects of using a new non-invasive approach in the study of the oxidationreduction balance of human skin.

Study of antioxidant properties by voltammetry

A highly attractive, convenient and especially sensitive voltammetric approach for the study of antioxidant properties and determination of their activity is suggested in this work, where antioxidants are substances, which interrupt radical-chain oxidation processes in organic and inorganic molecules. The comparative analysis of the activity of well-known antioxidants such as ascorbic and citric acids, glucose, their compound solutions, some food products (green tea extract, apple vinegar) and pharmaceuticals (haemodesum, polyglucinum, Ringer solution) has been carried out. The character of the antioxidant influence on the oxygen electrochemical reduction has been investigated. Finally the use of these substances for prophylactic purposes has been recommended.

Disposable Potentiometric Sensory System for Skin Antioxidant Activity Evaluation

Sensors

The skin is a natural barrier between the external and internal environment. Its protective functions and the relationship of its state with the state of health of the organism as a whole are very important. It is known that oxidant stress (OS) is a common indicator of health status. This paper describes a new sensory system for monitoring OS of the skin using antioxidant activity (AOA) as its criteria. The contact hybrid potentiometric method (CHPM) and new electrochemical measuring scheme were used. A new sensory system, including disposable modified screen-printed carbon and silver electrodes covered by membrane impregnated by mediator, was developed. Its informative ability was demonstrated in the evaluation of the impact of fasting, consumption of food and food enriched by vitamins (antioxidants) on skin AOA. This device consisting of a sensory system and potentiometric analyzer can be used in on-site and in situ formats.

Electrochemical monitoring of native catalase activity in skin using skin covered oxygen electrode

Biosensors & bioelectronics, 2017

A skin covered oxygen electrode, SCOE, was constructed with the aim to study the enzyme catalase, which is part of the biological antioxidative system present in skin. The electrode was exposed to different concentrations of H2O2 and the amperometric current response was recorded. The observed current is due to H2O2 penetration through the outermost skin barrier (referred to as the stratum corneum, SC) and subsequent catalytic generation of O2 by catalase present in the underlying viable epidermis and dermis. By tape-stripping the outermost skin layers we demonstrate that SC is a considerable diffusion barrier for H2O2 penetration. Our experiments also indicate that skin contains a substantial amount of catalase, which is sufficient to detoxify H2O2 that reaches the viable epidermis after exposure of skin to high concentrations of peroxide (0.5-1mM H2O2). Further, we demonstrate that the catalase activity is reduced at acidic pH, as compared with the activity at pH 7.4. Finally, exp...