title: Protective activity of hydroxytyrosol metabolites on erythrocyte oxidative-induced hemolysis.
abstract: The capacity of important hydroxytyrosol metabolites (homovanillyl alcohol, hydroxytyrosol acetate, homovanillyl alcohol acetate, hydroxytyrosol 3' and 4'-O-glucuronides, and homovanillyl alcohol 4'-O-glucuronide) to protect red blood cells (RBCs) from oxidative injury induced by the radical initiator 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) or by the natural radical initiator H2O2 was evaluated. In the presence of AAPH, all compounds showed to protect RBCs from hemolysis in a dose-dependent manner, exccept for the homovanillyl alcohol glucuronide, with the order of activity being at 20 μM hydroxytyrosol > hydroxytyrosol glucuronides = hydroxytyrosol acetate = homovanillyl alcohol = homovanillyl acetate > homovanillyl alcohol glucuronide. At 10 μM, hydroxytyrosol, hydroxytyrosol acetate, and hydroxytyrosol glucuronides still protected hemoglobine from oxidation and from morphological RBC changes. In the presence of H2O2, hydroxytyrosol showed to significantly protect RBCs from oxidative hemolysis in a dose-dependent manner, but the hydroxytyrosol glucuronides showed only a limited protection that was independent of the concentration used.
authors.affiliation: Centro de Investigação em Química and Departamento de Química, Faculdade de Ciências, Universidade do Porto , Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
authors.forename: Fátima
authors.initials: F
authors.lastname: Paiva-Martins
authors.forename: Aníbal
authors.initials: A
authors.lastname: Silva
authors.forename: Vasco
authors.initials: V
authors.lastname: Almeida
authors.forename: Mafalda
authors.initials: M
authors.lastname: Carvalheira
authors.forename: Cristina
authors.initials: C
authors.lastname: Serra
authors.forename: José Enrique
authors.initials: JE
authors.lastname: Rodrígues-Borges
authors.forename: João
authors.initials: J
authors.lastname: Fernandes
authors.forename: Luis
authors.initials: L
authors.lastname: Belo
authors.forename: Alice
authors.initials: A
authors.lastname: Santos-Silva
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D020011:Protective Agents / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D020011:Protective Agents; C005975:3,4-dihydroxyphenylethanol; D010626:Phenylethyl Alcohol