Effects of olive oil polyphenols on erythrocyte oxidative damage.
Many studies have investigated the protective effects of oleuropein and hydroxytyrosol against cell injury, but few have investigated the protective effects of oleuropein aglycones 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA) and 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde (3,4-DHPEA-EDA). The present work studied and compared the capacity of these four compounds, found at high concentrations in olive oil, to protect red blood cells (RBCs) from oxidative injury. The in vitro oxidative stress of RBCs was induced by the water-soluble radical initiator 2,2'-azo-bis(2-amidinopropane) dihydrochloride. RBC changes were evaluated either by optical microscopy or by the amount of hemolysis. All compounds were shown to significantly protect RBCs from oxidative damage in a dose-dependent manner. The order of activity at 20 microM was: 3,4-DHPEA-EDA > hydroxytyrosol > oleuropein > 3,4-DHPEA-EA. Even at 3 microM, 3,4-DHPEA-EDA and hydroxytyrosol still had an important protective activity. However, deleterious morphological RBC changes were much more evident in the presence of hydroxytyrosol than with 3,4-DHPEA-EDA. For the first time it was demonstrated that 3,4-DHPEA-EDA, one of most important olive oil polyphenols, may play a noteworthy protective role against ROS-induced oxidative injury in human cells since lower doses of this compound were needed to protect RBCs in vitro from oxidative mediated hemolysis.
Paiva-Martins
Fátima
F
Centro de Investigação em Química (CIQ), Departamento de Química, Faculdade de Ciências, Universidade do Porto, Porto, Portugal. mpmartin@fc.up.pt
Fernandes
João
J
Rocha
Susana
S
Nascimento
Henrique
H
Vitorino
Rui
R
Amado
Francisco
F
Borges
Fernanda
F
Belo
Luís
L
Santos-Silva
Alice
A