Hydroxytyrosyl acetate contributes to the protective effects against oxidative stress of virgin olive oil

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.

► Direct treatment of HepG2 cells with HTy-Ac reduces ROS generation and increases GPx activity. ► After t-BOOH exposure, pretreatment with HTy-Ac counteracts cell viability damage and decreases generation of ROS from 1μM. ► Furthermore, pretreatment with HTy-Ac counterbalances the decrease of GSH and protects from lipid peroxidation from 0.5 μM. ► Finally, pretreatment with HTy-Ac decreases the activity of antioxidant enzymes, GPx and GR, from 0.5 μM. ► HTy-Ac presents antioxidative stress protective effects similar or slightly higher than that of HTy at physiological concentrations.