Olive oil hydroxytyrosol protects human erythrocytes against oxidative damages

Abstract

Hydroxytyrosol, the major representative phenolic compound of virgin olive oil, is a dietary component. Its possible protective effect on hydrogen peroxide (H 2O 2)-induced oxidative alterations was investigated in human erythrocytes. Cells were pretreated with micromolar hydroxytyrosol concentrations and then exposed to H 2O 2 over different time intervals. Subsequently, erythrocytes were analyzed for oxidative hemolysis and lipid peroxidation. Our data demonstrate that hydroxytyrosol prevents both oxidative alterations, therefore, providing protection against peroxide-induced cytotoxicity in erythrocytes. The effect of oxidative stress on erythrocyte membrane transport systems, as well as the protective role of hydroxytyrosol, also were investigated in conditions of nonhemolytic mild H 2O 2 treatment. Under these experimental conditions, a marked decrease in the energy-dependent methionine and leucine transport is observable; this alteration is quantitatively prevented by hydroxytyrosol pretreatment. On the other hand, the energy-independent glucose transport is not affected by the oxidative treatment. The reported data give new experimental support to the hypothesis of a protective role played by nonvitamin antioxidant components of virgin olive oil on oxidative stress in human systems.