Acta Pharm. 71 (2021) 131-141

 

full paper

Original research paper

 

Protective effects of olive oil phenolics oleuropein and hydroxytyrosol against hydrogen peroxide-induced DNA damage in human peripheral lymphocytes

NATAŠA ZORIĆ, NEVENKA KOPJAR, JADRANKA VUKOVIĆ RODRIGUEZ, SINIŠA TOMIĆ and IVAN KOSALEC

ivan_kosalec@pharma.hr

1 Agency for Medicinal Products and Medical Devices of Croatia (HALMED)

HR-10000 Zagreb, Croatia

2 Institute for Medical Research and Occupational Health

HR-10000 Zagreb, Croatia

3 University of Zagreb Faculty of Pharmacy and Biochemistry

Department of Pharmaceutical Analysis, HR-10000 Zagreb, Croatia

4 University of Zagreb Faculty of Pharmacy and Biochemistry

Department of Microbiology, HR-10000 Zagreb, Croatia

Accepted March 10, 2020

Published online July 3, 2020

 

This study investigates antioxidant capacity and protective effects of phenolic compounds oleuropein (OLP) and hydroxytyrosol (HT), present in olive oil and olive leaves, against H2O2-induced DNA damage in human peripheral lymphocytes. Antioxidant potency was determined using the measurement of radical-scavenging activity (ABTS∙+ assay), ferric reducing power (FRAP assay) and cupric reducing antioxidant capacity (CUPRAC assay). Both substances were found to be potent antioxidant agents due to their free radical-scavenging activities. Antigenotoxic effects of oleuropein and hydroxytyrosol against H2O2-induced damage in human lymphocytes were evaluated in vitro by alkaline comet assay. At tested concentrations (1, 5, 10 µmol L–1), oleuropein and hydroxytyrosol did not induce a significant increase of primary DNA damage in comparison with the negative control. Pretreatment of human lymphocytes with each of the substances for 120 min produced a dose-dependent reduction of primary DNA damage in the tested cell type. Hydroxytyrosol showed a better protective effect against H2O2-induced DNA breaks than oleuropein which could be associated with their free radical-scavenging efficacy.

 

Keywords: oleuropein, hydroxytyrosol, olive, antioxidant activity, DNA damage, human lymphocytes, comet assay