Olive phenol hydroxytyrosol prevents passive smoking-induced oxidative stress

Background-Oxidative stress is involved in the onset of several degenerativ e disorders, and epidemiological studies indicate that a high intake of die tary antioxidants, as in the case of the Mediterranean basin, is protective . Olive mill waste waters (OMWWs) are a byproduct of olive oil production r ich 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 ox idative stress in rats by evaluating the urinary excretion of 8-iso-prostag landin (PG) F-2 alpha (iPF(2 alpha)-III). Methods and Results-An OMWW extract (5 mg/kg, providing 414 mug/kg of hydro xytyrosol) 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 g-iso-PGF(2 alpha) was evaluated as an index of oxidative stress-induced in vivo lipid peroxidatio n, The exposure of rats to passive smoking increased the urinary excretion of 8-iso-PGF(2 alpha) 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 increas e at 48 hours and resulted in lower increments (34+/-18% versus 55+/-10%) o f 8-iso-PGF(2 alpha) excretion at 96 hours. Conclusions-A low dose of hydroxytyrosol, administered through OMWW, reduce s the consequences of sidestream smoke-induced oxidative stress in rats.