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.

Labeled extra virgin olive oil as food supplement; phenolic compounds in oils from some autochthonous Croatian olives

“…More recent studies and reviews, for example, by Oliveras-Lopez et al (2014), Garcia-Martinez et al (2014a, 2014b, Estruch et al (2013), Sofi et al (2010) and Fung et al (2009) fit the same general picture presented by Keys (1970) and Martinez-Gonzales et al (2002) and López-Miranda et al (2010) or Lipworth et al (1997). The phenolic compounds, naturally present in EVOO-s are deemed to be of central importance for these beneficial cardiovascular, according to Estruch et al (2013), Fung et al (2009), Valls et al (2015), antiatherogenic/antiinflammatory, Scoditti et al (2014), Lu et al (2013), Cabrerizo et al (2013), anticancer, Hashim et al (2008), Lamy et al (2014), Hashim et al (2014), antioxidant and antimicrobial effects Cicerale et al (2012), Karaosmanoglu et al (2010), Paiva-Martins et al (2013), Giordano et al (2014).…”

Hydroxytyrosol in the Prevention of the Metabolic Syndrome and Related Disorders

“…Since, numerous studies were published and confirmed that HT protect against ROS production in human vascular endothelial cells, erythrocytes and renal epithelial tubular cells (5 to 80 µM) [111,112,113], displays scavenger activity for peroxynitrous acid (5 µM to 1 mM) [114,115] and has a protective role on deoxyribonucleic acid damages associated to peroxinitrous acid (0.05 to 1 mM) [114]. Moreover, it can inhibit superoxide anion burst from macrophages but not from neutrophils where it can only scavenge hydrogen peroxide (1 to 50 µM) [116].…”

Hydroxytyrosol and tyrosol sulfate metabolites protect against the oxidized cholesterol pro-oxidant effect in Caco-2 human enterocyte-like cells

“…The literature on phenolic absorption and metabolism after olive oil ingestion is extensive [3][4] ; however, there are still several issues to be clarified. Some complex olive oil polyphenols, among the secoiridoids, are relatively stable under gastric conditions and reach the 15 intestine where they may be directly absorbed or metabolised under absorption 5 ; most of the complex olive oil polyphenols however seems to undergo gastrointestinal biotransformation (see de Bock for an excellent review ) 6 , increasing the relative amount of simple phenols, mainly TYR and HT, entering the small and large intestine 7 . At this location the concentration of simple phenols may be quite high, in the high M range 7 , and they might exert direct protective effects by scavenging reactive species and/or preventing their formation 8 .…”