Olive oil hydroxytyrosol protects human erythrocytes against oxidative damages

Hydroxytyrosol, the major representative phenolic compound of virgin olive oil, is a dietary component. Its possible protective effect on hydrogen per oxide (H2O2)-induced oxidative alterations was investigated in human erythr ocytes. Cells were pretreated with micromolar hydroxytyrosol concentrations and then exposed to H2O2 over different time intervals. Subsequently, eryt hrocytes were analyzed for oxidative hemolysis and lipid peroxidation. Our data demonstrate that hydroxytyrosol prevents both oxidative alterations, t herefore, providing protection against peroxide-induced cytotoxicity in ery throcytes. The effect of oxidative stress on erythrocyte membrane transport systems, as well as the protective role of hydroxytyrosol, also were inves tigated in conditions of nonhemolytic mild H2O2 treatment. Under these expe rimental conditions, a marked decrease in the energy-dependent methionine a nd leucine transport is observable; this alteration is quantitatively preve nted by hydroxytyrosol pretreatment. On the other hand, the energy-independ ent glucose transport is not affected by the oxidative treatment. The repor ted data give new experimental support to the hypothesis of a protective ro le played by nonvitamin antioxidant components of virgin olive oil on oxida tive stress in human systems. (C) Elsevier Science Inc. 1999. All rights re served.