Olive Phenol Hydroxytyrosol Prevents Passive Smoking–Induced Oxidative Stress

Abstract

Background—Oxidative stress is involved in the onset of several degenerative disorders, and epidemiological studies indicate that a high intake of dietary antioxidants, as in the case of the Mediterranean basin, is protective. Olive mill waste waters (OMWWs) are a byproduct of olive oil production rich in phenolic antioxidants, such as hydroxytyrosol. We tested the effects of a low dose of an OMWW extract in a model of sidestream smoke–induced oxidative stress in rats by evaluating the urinary excretion of 8-iso-prostaglandin (PG) F 2α(iPF 2α-III). Methods and Results—An OMWW extract (5 mg/kg, providing 414 μg/kg of hydroxytyrosol) was administered to rats daily for 4 days, during which time the animals were exposed to sidestream smoke for 20 minutes once a day. Daily urines were collected, and the urinary excretion of 8-iso-PGF 2α was evaluated as an index of oxidative stress–induced in vivo lipid peroxidation. The exposure of rats to passive smoking increased the urinary excretion of 8-iso-PGF 2α by 44±4.2% at 48 hours and by 55±10% at 96 hours. Treatment with the OMWW extract was able to completely prevent the increase at 48 hours and resulted in lower increments (34±18% versus 55±10%) of 8-iso-PGF 2α excretion at 96 hours. Conclusions—A low dose of hydroxytyrosol, administered through OMWW, reduces the consequences of sidestream smoke–induced oxidative stress in rats.