New in vitro approaches to evaluate antioxidant activity of food and their application to real samples

Several epidemiological studies have shown that the production of reactive oxygen species (ROS) contributes to the risk factors for chronic pathological conditions, such as cardiovascular diseases, cancer and diabetes [1]. A diet that includes foods rich in antioxidant compounds, in combination with a correct lifestyle, represents a possible approach to counteract the negative effects of the oxidative stress. On these bases, several studies have been focused on the determination of antioxidant properties of food; the methods used to assess the antioxidant activity differ from each other in terms of chemical bases and reaction conditions. Considering the chemical diversity of the different classes of molecules, a single assay cannot accurately reflect their antioxidant activity. The aim of this study was to set up and apply different in vitro approaches for a fast screening of the antioxidant activity of different foods/food supplements, including wine. The methods included: 1) Folin-Ciocalteu\u2019s assay for the quantification of total polyphenol content [2]; 2) DPPH (1,1-diphenyl-2-picrylhydrazyl) spectrophotometric assay; 3) Trolox Equivalent Antioxidant Capacity (TEAC) spectrophotometric assay for measuring the capacity of the samples to scavenge ABTS radical [3]. Two novel approaches were also used in parallel: 1) High Performance Thin Layer Chromatography (HPTLC) for the semi-quantitative measure of antioxidant activity associated with wine and its specific compounds; 2) detection by an electrochemical biosensor, an analytical device that includes a biological detector coupled to a chemical transducer. Although the method based on biosensor needs further improvement, the first results indicate that this approach could be suitable for a fast measure of antioxidant activity. In conclusion, all approaches used in this research show some limitations, but when integrated they could represent a useful tool to assess antioxidant properties of foodstuff, reflecting at least in part the potential in vivo protecting activity