Hydroxytyrosol Disposition in Humans

Abstract

Background: Animal and in vitro studies suggest that phenolic compounds in virgin olive oil are effective antioxidants. In animal and in vitro studies, hydroxytyrosol and its metabolites have been shown to be strong antioxidants. One of the prerequisites to assess their in vivo physiologic significance is to determine their presence in human plasma. Methods: We developed an analytical method for both hydroxytyrosol and 3-O-methyl-hydroxytyrosol in plasma. The administered dose of phenolic compounds was estimated from methanolic extracts of virgin olive oil after subjecting them to different hydrolytic treatments. Plasma and urine samples were collected from 0 to 12 h before and after 25 mL of virgin olive oil intake, a dose close to that used as daily intake in Mediterranean countries. Samples were analyzed by capillary gas chromatography-mass spectrometry before and after being subjected to acidic and enzymatic hydrolytic treatments. Results: Calibration curves were linear (r >0.99). Analytical recoveries were 42-60%. Limits of quantification were <1.5 mg/L. Plasma hydroxytyrosol and 3-O-methyl-hydroxytyrosol increased as a response to virgin olive oil administration, reaching maximum concentrations at 32 and 53 min, respectively (P <0.001 for quadratic trend). The estimated hydroxytyrosol elimination halflife was 2.43 h. Free forms of these phenolic compounds were not detected in plasma samples. Conclusions: The proposed analytical method permits quantification of hydroxytyrosol and 3-O-methyl-hydroxytyrosol in plasma after real-life doses of virgin olive oil. From our results, ϳ98% of hydroxytyrosol appears to be present in plasma and urine in conjugated

Diagnostic Performance of Urinary Resveratrol Metabolites as a Biomarker of Moderate Wine Consumption

“…After the washout periods as well as after gin intervention, very low concentrations of resveratrol glucuronide were detected in urine, possibly from previous intake of food with very low resveratrol content or interference from compounds with a similar structure, such as estrogens. Similar results have been observed after washout periods in studies investigating quercetin (44 ) and other polyphenols (45 ), as well as for hydroxytyrosol, a metabolite of dopamine, in an study of olive oil (46 ). Mean (SD) TRM concentrations did not differ significantly in response to various periods of no wine intake in our studies [43.4 (23.5), 51.5 (36.1), and 40.5 (33.6) nmol/g for sparkling, white, and red wine, respectively] as part of the larger PREDIMED Study.…”

New perspectives on bioactivity of olive oil: evidence from animal models, human interventions and the use of urinary proteomic biomarkers

“…As a result OO phenolic compounds are further absorbed in the small intestine (23) . Measuring the bioavailability of these compounds in plasma and urine reveals that OO phenolics undergo a conjugation process of methylation, glucuronidation and sulfation indicating that there is phase 2 metabolism involved during the absorption of these compounds (24)(25)(26)(27) . The between-subjects variability in human absorption and metabolism of OO phenolics may explain differences in proportion of methyl, glucuronide and sulphate conjugates reported (28)(29)(30) .…”

Virgin olive oil in preventive medicine: From legend to epigenetics

“…2) [67]. It was also noted that daily intake of 50 mL of EVOO (equivalent to two spoons of EVOO for meal, in a main dish and in vegetables, respectively) contains 200 mg/mL of oleocanthal (of which 60-90% is absorbed), for a daily intake of about 9 mg [69,70]. This dose is only around onetenth of what is recommend for an adult for a painful illness, but it is known that small doses of aspirin, another COX inhibitor, have beneficial effects on several serious cardiovascular conditions [71][72][73].…”