The effects of virgin olive oil phenols, hydroxytyrosyl acetate (HTy-Ac) and hydroxytyrosol (HTy), on cell integrity and steady-state values of cellular redox status were assessed in HepG2 cells, as well as their potential protective effects against oxidative stress induced by tert-butyl hydroperoxide (t-BOOH). Direct treatment for 20 h with 0.5-10 μM HTy or HTy-Ac reduced ROS generation and increased glutathione peroxidase activity at the higher concentrations. Furthermore, after t-BOOH exposure, pretreatment with HTy-Ac and HTy for 2 or 20 h counteracted cell viability damage from 1 μM, counterbalanced reduced glutathione levels from 0.5 μM, protected against lipid peroxidation from 0.5 μM, decreased ROS generation from 1 μM as well as antioxidant enzyme activities from 1 μM. All these changes were statistically significant. HTy-Ac presents antioxidative stress protective effects at physiological concentrations similar to or even slightly higher than that of HTy, thus contributing to the protective role of virgin olive oil. © 2011 Elsevier Ltd. All rights reserved.

This work was supported by projects AGL2007-64042, AGL2007-66373-C03/ALI and CSD2007-00063 from the Consolider-Ingenio Program of the Spanish Ministry of Science and Innovation (CICYT), a grant (RTA2007-000036-00-00) from the Research National Institute of Food, Agriculture and Technology (INIA), a contract (110105090014) with CSIC-IFAPA.

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