Oxidative DNA damage is prevented by extracts of olive oil, hydroxytyrosol, and other olive phenolic compounds in human blood mononuclear cells and HL60 cells.
Our aim in this study was to provide further support to the hypothesis that phenolic compounds may play an important role in the anticarcinogenic properties of olive oil. We measured the effect of olive oil phenols on hydrogen peroxide (H(2)O(2))-induced DNA damage in human peripheral blood mononuclear cells (PBMC) and promyelocytic leukemia cells (HL60) using single-cell gel electrophoresis (comet assay). Hydroxytyrosol [3,4-dyhydroxyphenyl-ethanol (3,4-DHPEA)] and a complex mixture of phenols extracted from both virgin olive oil (OO-PE) and olive mill wastewater (WW-PE) reduced the DNA damage at concentrations as low as 1 micromol/L when coincubated in the medium with H(2)O(2) (40 micromol/L). At 10 micromol/L 3,4-DHPEA, the protection was 93% in HL60 and 89% in PBMC. A similar protective activity was also shown by the dialdehydic form of elenoic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) on both kinds of cells. Other purified compounds such as isomer of oleuropein aglycon (3,4-DHPEA-EA), oleuropein, tyrosol, [p-hydroxyphenyl-ethanol (p-HPEA)] the dialdehydic form of elenoic acid linked to tyrosol, caffeic acid, and verbascoside also protected the cells against H(2)O(2)-induced DNA damage although with a lower efficacy (range of protection, 25-75%). On the other hand, when tested in a model system in which the oxidative stress was induced by phorbole 12-myristate 13-acetate-activated monocytes, p-HPEA was more effective than 3,4-DHPEA in preventing the oxidative DNA damage. Overall, these results suggest that OO-PE and WW-PE may efficiently prevent the initiation step of carcinogenesis in vivo, because the concentrations effective against the oxidative DNA damage could be easily reached with normal intake of olive oil.
Fabiani
Roberto
R
Dipartimento di Specialità Medico-Chirurgiche e Sanità Pubblica, Sezione di Epidemiologia Molecolare ed Igiene Ambientale, Università degli Studi di Perugia, 06126 Perugia, Italy. fabirob@unipg.it
Rosignoli
Patrizia
P
De Bartolomeo
Angelo
A
Fuccelli
Raffaela
R
Servili
Maurizio
M
Montedoro
Gian Francesco
GF
Morozzi
Guido
G
D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D004249:DNA Damage / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018922:HL-60 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D031658:Olea / Q000737:chemistry; D000069463:Olive Oil; D018384:Oxidative Stress / Q000187:drug effects; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*
D000975:Antioxidants; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; C005975:3,4-dihydroxyphenylethanol; D006861:Hydrogen Peroxide; D010626:Phenylethyl Alcohol