Abstract

We investigated the oxidative modifications of lipids, proteins and antioxidants enzymes activities, in erythrocytes treated with H₂O₂ in the presence or absence of hydroxytyrosol (HT) at 37°C for 30 min. Conjugated dienes level was measured as biomarker of lipid peroxidation. Protein carbonyl level was measured as biomarker of protein oxidation. The antioxidants enzymes activities were evaluated by superoxide dismutase and catalase activities determinations. Conjugated dienes levels decreased in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H₂O₂. Protein carbonyl levels increased in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H₂O₂. In addition, this study showed a prospective protective action of HT of human erythrocytes from the attack of reactive oxygen species. In fact, a considerable increase of superoxide dismutase activity by 40% was showed after incubation of erythrocytes with HT at dose 5 µg/ml. Although, there were no significant differences in catalase activity in erythrocytes after hydroxytyrosol treatment as compared to erythrocytes treated with 0.2 mM H₂O₂. This study demonstrates that hydroxytyrosol prevents protein oxidation and lipid peroxidation caused by H₂O₂ treatment using erythrocytes cell model.

Key words: Hydroxytyrosol, thiol, erythrocytes, conjugated dienes, malondialdehyde, superoxide dismutase, catalase, peripheral blood mononuclear (PBL), peripheral blood mononuclear.

Abbreviation

SOD, superoxide dismutase; CAT, catalase; PBL, Peripheral blood mononuclear; HT, Hydroxytyrosol; SH, thiol; ROS, reactive oxygen species; DNPH, 2,4-dinitrophenylhydrazine; CD, Conjugated dienes; OD, optical density; DTPA, Tris–cacodylic acid– diethylenetriaminepenta-acetic acid; H₂O₂, hydrogen peroxide.