Determination of hydroxytyrosol and tyrosol in human urine after intake of extra virgin olive oil produced with an ultrasounds-based technology.

Extra virgin olive oil (EVOO) is a known source of antioxidants, such as phenolic compounds, useful in the prevention of non-infectious diseases (atherosclerosis, diabetes, cancer, and other diseases). In the present study, EVOO obtained using an innovative ultrasounds-based technology was found richer in total polyphenols, hydroxytyrosol and tyrosol, than EVOO obtained using a conventional mechanical technology. The urinary excretion in humans of hydroxytyrosol and tyrosol, after the administration of ultrasounds and mechanical EVOOs, respectively, was assessed and compared. The analytes were determined in urine samples, collected for 24 h, of six healthy people (3 men and 3 women, age 22-70 years and body mass index <30 kg/m) who ingested 20 g of oil for six consecutive days. A commercial refined olive oil was also used in the study to determine the baseline excretion levels of the two metabolites. High correlation coefficients (≥0.9311) were found between the amounts of the analytes ingested daily with EVOOs and those determined in the 24-h urines. The results clearly indicated that the EVOO obtained with the ultrasound process was characterized by the highest concentration of biophenols which were consequently available in greater quantities after ingestion, indicating that it represents a high-quality product containing high levels of beneficial compounds such as biophenols readily assimilable by the human body.