Determinazione e valutazione dell'attività antiossidante di olii extravergine di oliva italiani mediante saggi chimici e cellulari

Italy is the first country in Europe in terms of number of Protected Designation of Origin (PDO) extra-virgin olive oils (EVOOs). Extra-Virgin Olive Oils (EVOOs) contains a variety of phenolic molecules that are highly valuable to the quality of the oil with regard to sensory and health characteristics. Its composition greatly varies with genetic, agronomic and environmental factors. The analysis of olive oil minor components, such as polyphenols, could be used for the discrimination on a geographical basis and could be useful in the prevention of frauds and false declarations. Therefore, the goal of this study was to investigate the difference in total phenolic content and antioxidant activity of 293 samples of monovarietal and multivarietal EVOOs samples, including PDO oils, from different Italian geographic areas. The analysis of total concentration of phenolic compounds in extra virgin olive oils was determined through Folin-Ciocalteu method, while antioxidant activity was evaluated by four different assay based on different reaction mechanisms and substrates. The final aim of the project will be to create a composition data bank with a great number of Italian EVOO samples. Results showed that Total Phenolic Contents values ranged from 50 to 680 mg gallic acid equivalents/Kg of oil and antioxidants activity values ranged from 0.94 to 12.43 µmol Trolox eq./g of oil, from 0.15 to 2.72 µmol Trolox eq./g of oil, 0.27 to 3.82 µmol Trolox eq./g of oil and 1.09 to 21.37 µmol Trolox eq./g of oil for ABTS, DPPH, FRAP and ORAC assays, respectively. Macrophage function as control switches of the immune system, maintaining the balance between pro and anti-inflammatory activities. Classic polarization (M1) and activation of macrophages into pro-inflammatory cells is characterized by generation of reactive oxygen and nitrogen species (ROS/RNS) and pro-inflammatory cytokines, including TNF-a and IL-1ß. Alternative activation profile (M2) is characterized by secretion of anti-inflammatory cytokines. Bioactive food components, such as polyphenols, have gained attention for their anti-inflammatory properties. EVOO, a polyphenol rich food, has many beneficial effects on human health, including anti-inflammatory effects. Moreover, we evaluated the antioxidant activity of bioactive molecules extracted from dried olive leaves and vegetation water through an in vitro cell culture system. In this study, we investigated the hypothesis that EVOO polyphenol extracts has anti-inflammatory effects on macrophage phenotype favoring an anti-inflammatory state. Macrophages deriving from THP-1 cells were cultured at a starting density of 2x104 cells per well for 24h. Cells were then activated for an additional 24h with either LPS (1µg/ml). Specific cytokynes were detected and quantified by ELISA assay. In vitro, EVOO polyphenolic extracts attenuated inflammatory with significantly decreased macrophage response to M1 activation. This was evidenced by a significant decrease of pro-inflammatory cytokines secretion (TNF-a, IL-1ß) after stimulation with LPS 1µg/ml. Data showed a significant decrease of ROS production and MDA level, while cell vitality increased.