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In vitro studies have shown phenolics in olive oil to be strong radical scavengers. The absorption and elimination of two radiolabeled phenolic constituents of olive oil, hydroxytyrosol and tyrosol were studied in vivo using rats. Compounds were administered intravenously (in saline) and orally (in oil-and water-based solutions). For both compounds, the intravenously and orally administered oil-based dosings resulted in significantly greater elimination of the phenolics in urine within 24 h than the oral, aqueous dosing method. There was no significant difference in the amount of phenolic compounds eliminated in urine between the intravenous dosing method and the oral oil-based dosing method for either tyrosol or hydroxytyrosol. Oral bioavailability estimates of hydroxytyrosol when administered in an olive oil solution and when dosed as an aqueous solution were 99% and 75%, respectively. Oral bioavailability estimates of tyrosol, when orally administered in an olive oil solution and when dosed as an aqueous solution were 98% and 71%, respectively. This is the first study that has used a radiolabeled compound to study the in vivo biological fates of hydroxytyrosol and tyrosol.

We have observed among patients of the Southern Community Hospice Programme that up to 25% experience acute delirium when treated with morphine and improve when the opioid is changed to oxycodone or fentanyl. This study aimed to confirm by a prospective trial that oxycodone produces less delirium than morphine in such patients. Oxycodone was administered by a continuous subcutaneous infusion, as this allowed more flexible and reliable dosing, and patients were monitored for any adverse reactions to the drug. Thirteen patients completed the study. Statistically significant improvements in mental state and nausea and vomiting occurred following a change from morphine to oxycodone. Pain scores improved but did not reach a level of statistical significance. The phenotype status of the patients was tested to establish their capacity to metabolize oxycodone. One patient who did not achieve adequate pain control proved to be a poor metabolizer. These results show that oxycodone administered by the subcutaneous route can provide effective analgesia without significant side effects in patients with morphine-induced delirium. This treatment allows patients to remain more comfortable and lucid in their final days. A small proportion of patients who do not metabolize oxycodone effectively may not receive this benefit.

Hydroxytyrosol is quantitatively and qualitatively the principal phenolic antioxidant in olive oil. Recently it was shown that hydroxytyrosol and five metabolites were excreted in urine when hydroxytyrosol was dosed intravenously or orally in an olive oil solution to rats. The conclusive identification of three metabolites of hydroxytyrosol by MS/MS as a monosulfate conjugate, a 3-O-glucuronide conjugate, and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid) has been established in this investigation. The structural configurations of the glucuronide conjugate and 4-hydroxy-3-methoxyphenylacetic acid were confirmed by (1)H NMR. The radical scavenging potencies of homovanillic acid, homovanillic alcohol, hydroxytyrosol, and the metabolites were examined with the radical 2,2-diphenyl-1-picrylhydrazyl. These studies showed them to be potent antioxidants with SC(50) values of 14.8 and 11.4 microM for homovanillic acid and homovanillic alcohol, respectively. The 3-O-glucuronide conjugate was more potent than hydroxytyrosol, with an SC(50) of 2.3 in comparison to 11.0 microM, and the monosulfate conjugate was almost devoid of radical scavenging activity.

Epidemiological studies have shown that the incidence of heart disease and certain cancers is lower in the Mediterranean region. This has been attributed to the high consumption of olive oil in the Mediterranean diet, which contains polyphenolic compounds with antioxidant activity. Although many in vitro studies have been performed to elucidate mechanisms by which these compounds may act, there are virtually no data relating to their fate after ingestion. Therefore, we decided to investigate the intestinal absorption of one of the major olive oil polyphenolics, oleuropein. To do this, a novel in situ intestinal perfusion technique was developed, and the absorption of oleuropein was studied under both iso-osmotic and hypotonic luminal conditions. Oleuropein was absorbed, with an apparent permeability coefficient (P:(app)) of 1.47 +/- 0.13 x 10(-6) cm/s (+/-SE) observed under iso-osmotic conditions. The mechanism of absorption is unclear but may involve transcellular transport (SGLT1) or paracellular movement. Under hypotonic conditions, the permeability of oleuropein was significantly greater (5.92 +/- 0.49 x 10(-6) cm/s, P: < 0.001). This increase is thought to be due to an increase in paracellular movement facilitated by the opening of paracellular junctions in response to hypotonicity. Overall, we determined that the olive oil polyphenolic oleuropein can be absorbed, albeit poorly, from isolated perfused rat intestine. Therefore, it is possible that it or its metabolites may confer a positive health benefit after the consumption of olive oil, most likely via an antioxidant mechanism.

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Typical components of the Mediterranean diet, such as olive oil and red wine, contain high concentrations of complex phenols, which have been suggested to have an important antioxidant role. The aim of the present work was to determine the inhibitory potency of compounds such as oleuropein, hydroxytyrosol, and other structurally related compounds, such as gallic acid, toward reactive oxygen species generation and free radical scavenging ability. The potency of these compounds was also examined with respect to protecting in vitro low-density lipoprotein oxidation. These studies indicate that complex phenols, such as hydroxytyrosol, and gallic acid both inhibit free radical generation and act as free radical scavengers. The use of three different approaches to determine antioxidant potency demonstrates that activity in one test does not necessarily correlate with activity in another. It was also demonstrated that the presence of two phenolic groups is not always associated with antioxidant activity.