Protective effect of hydroxytyrosol and tyrosol against oxidative stress in kidney cells

Bioavailability studies in animals and humans fed with extravirgin olive oil demonstrated that hydroxytyrosol and tyrosol, the major simple phenolic compounds in extravirgin olive oil, are dose-dependently absorbed and excreted. Once absorbed, they undergo extensive metabolism; hydroxytyrosol and tyrosol concentrate mainly in the kidney, where they may exert an important role in the prevention of oxidative stress induced renal dysfunction. In this study we monitored the ability of hydroxytyrosol and tyrosol to protect renal cells (LLC-PK1) following oxidative damage induced by H2O2. Oxidative stress was evaluated by monitoring the changes of the membrane lipid fraction. Hydroxytyrosol exerted a significant antioxidant action, inhibiting the production of MDA, fatty acids hydroperoxides and 7-ketocholesterol, major oxidation products of unsaturated fatty acids and cholesterol, and thus protecting the cells from H2O2-induced damage. Tyrosol, instead, in this experimental model, did not exert any protective effect.