Randomized controlled study of the urinary excretion of biophenols following acute and chronic intake of olive leaf supplements

Kendall, Megan; Batterham, Marijka; Callahan, Damien L.; Jardine, Daniel; Prenzler, Paul D.; Robards, Kevin; Ryan, Danielle

doi:10.1016/j.foodchem.2011.07.101

Cited by 23 publications

(29 citation statements)

References 31 publications

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“…Five male and five female subjects were recruited within the University of Auckland via email advertising. This sample size is comparable to previous studies in this field [5,[9][10][11][12][13]. Subjects were aged 42.8 ± 7.4 years (range 31.7-54.0) and with BMI 26.9 ± 1.9 kg/m 2 (range 24.6-29.8).…”

supporting

confidence: 70%

“…Our findings contrast to the only study that previously examined oleuropein metabolism taken as OLE. After chronic ingestion of OLE, phase II metabolites of oleuropein were almost exclusively found in urine (glucuronidated at different positions), with no conjugated metabolites of hydroxytyrosol . Phase II metabolites of oleuropein were detected here, but these could not be quantified due to a lack of a standard.…”

Section: Bioavailability Parameters Of Oleuropein and Conjugated Metamentioning

confidence: 69%

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Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaeaL.) leaf extract

Bock

Thorstensen

Derraik

et al. 2013

Mol. Nutr. Food Res.

192

199

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Phenolic compounds derived from the olive plant (Olea europaea L.), particularly hydroxytyrosol and oleuropein, have many beneficial effects in vitro. Olive leaves are the richest source of olive phenolic compounds, and olive leaf extract (OLE) is now a popular nutraceutical taken either as liquid or capsules. To quantify the bioavailability and metabolism of oleuropein and hydroxytyrosol when taken as OLE, nine volunteers (five males) aged 42.8 ± 7.4 years were randomized to receive either capsulated or liquid OLE as a single lower (51.1 mg oleuropein, 9.7 mg hydroxytyrosol) or higher (76.6 mg oleuropein, 14.5 mg hydroxytyrosol) dose, and then the opposite strength (but same formulation) a week later. Plasma and urine samples were collected at fixed intervals for 24 h post-ingestion. Phenolic content was analyzed by LC-ESI-MS/MS. Conjugated metabolites of hydroxytyrosol were the primary metabolites recovered in plasma and urine after OLE ingestion. Peak oleuropein concentrations in plasma were greater following ingestion of liquid than capsule preparations (0.47 versus 2.74 ng/mL; p = 0.004), but no such effect was observed for peak concentrations of conjugated (sulfated and glucuronidated) hydroxytyrosol (p = 0.94). However, the latter peak was reached earlier with liquid preparation (93 versus 64 min; p = 0.031). There was a gender effect on the bioavailability of phenolic compounds, with males displaying greater plasma area under the curve for conjugated hydroxytyrosol (11,600 versus 2550 ng/mL; p = 0.048). All conjugated hydroxytyrosol metabolites were recovered in the urine within 8 h. There was wide inter-individual variation. OLE effectively delivers oleuropein and hydroxytrosol metabolites to plasma in humans.

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supporting

confidence: 70%

Section: Bioavailability Parameters Of Oleuropein and Conjugated Metamentioning

confidence: 69%

Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaeaL.) leaf extract

Bock

Thorstensen

Derraik

et al. 2013

Mol. Nutr. Food Res.

192

199

View full text Add to dashboard Cite

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“…Related to OL, some authors suggest that it could be absorbed in the small intestine or colon. In this sense, Kendall et al reported that OL diffuses in the stomach and remained stable and intact at the gastric level during digestion being absorbed in the small intestine in healthy young adults [56]. Similarly, several studies have established that OL is stable at the gastric level during digestion, since the bioavailability of its main metabolite HTy is higher [57].…”

Section: Pharmacokinetics Of Secoiridoids From the Olive Treementioning

confidence: 98%

“…Surprisingly, it has been postulated that plasma peak at 1 hour (h) after OL administration for humans or 2 h for a murine model, although OL could be detected after 10 minutes (min) [56,63]. In addition, glucuronides and OL sulfate derivatives could be detected in plasma (at 23 min) or in the urine (at 8 h) after ingestion.…”

Section: Pharmacokinetics Of Secoiridoids From the Olive Treementioning

confidence: 99%

Potential Protective Role Exerted by Secoiridoids from Olea europaea L. in Cancer, Cardiovascular, Neurodegenerative, Aging-Related, and Immunoinflammatory Diseases

et al. 2020

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Iridoids, which have beneficial health properties, include a wide group of cyclopentane [c] pyran monoterpenoids present in plants and insects. The cleavage of the cyclopentane ring leads to secoiridoids. Mainly, secoiridoids have shown a variety of pharmacological effects including anti-diabetic, antioxidant, anti-inflammatory, immunosuppressive, neuroprotective, anti-cancer, and anti-obesity, which increase the interest of studying these types of bioactive compounds in depth. Secoiridoids are thoroughly distributed in several families of plants such as Oleaceae, Valerianaceae, Gentianaceae and Pedialaceae, among others. Specifically, Olea europaea L. (Oleaceae) is rich in oleuropein (OL), dimethyl-OL, and ligstroside secoiridoids, and their hydrolysis derivatives are mostly OL-aglycone, oleocanthal (OLE), oleacein (OLA), elenolate, oleoside-11-methyl ester, elenoic acid, hydroxytyrosol (HTy), and tyrosol (Ty). These compounds have proved their efficacy in the management of diabetes, cardiovascular and neurodegenerative disorders, cancer, and viral and microbial infections. Particularly, the antioxidant, anti-inflammatory, and immunomodulatory properties of secoiridoids from the olive tree (Olea europaea L. (Oleaceae)) have been suggested as a potential application in a large number of inflammatory and reactive oxygen species (ROS)-mediated diseases. Thus, the purpose of this review is to summarize recent advances in the protective role of secoiridoids derived from the olive tree (preclinical studies and clinical trials) in diseases with an important pathogenic contribution of oxidative and peroxidative stress and damage, focusing on their plausible mechanisms of the action involved.

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“…The main constituent is oleuropein, an iridoide monoterpene. 16 Herbal medicines are classified as dietary supplements or foods rather than drugs and do not require approval by regulatory drug agencies to be marketed. 11 Moreover, as a constituent of aqueous OLE, it showed high angiotensin-converting--enzyme (ACE) inhibitor activity.…”

Section: Introductionmentioning

confidence: 99%

Effects of high dose olive leaf extract on haemodynamic and oxidative stress parameters in normotensive and spontaneously hypertensive rats

Dekanski¹,

Mihailović-Stanojević

Milanovic

et al. 2014

JSCS

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The antihypertensive activity of olive leaf extract (OLE), a natural antioxidant is recognized, but its influence on the cardiovascular system when administered in a high dose has not yet been investigated. The aim of the present study was to determine the acute effects of excessive intake of standardized OLE on blood pressure, heart rate and oxidative status in both spontaneously hypertensive rats and normotensive Wistar rats. The systolic arterial pressure and heart rate were measured using a tail-cuff and pneumatic pulse detector before and 60 and 120 min after intragastric OLE administration. The activities of catalase, glutathione peroxidase, superoxide dismutase (SOD) and glutathione reductase in erythrocytes, as well as lipid peroxidation in plasma (pTBARS) were measured spectrophotometrically at the same time points. A high-dose of OLE did not influence blood pressure, heart rate or pTBARS in normotensive rats, while the SOD, catalase and glutathione reductase activities were significantly increased. The same dose significantly decreased blood pressure in hypertensive rats, but increased the pTBARS and SOD activity. Excessive oral intake of OLE induced moderate hypotensive effects only in spontaneously hypertensive rats, suggesting the absence of harmful hemodynamic effects after an oral overdose in both rat strains. However, its pro-oxidative role when given in a high dose in hypertensive organisms should not be neglected.

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Randomized controlled study of the urinary excretion of biophenols following acute and chronic intake of olive leaf supplements

Cited by 23 publications

References 31 publications

Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaeaL.) leaf extract

Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaeaL.) leaf extract

Potential Protective Role Exerted by Secoiridoids from Olea europaea L. in Cancer, Cardiovascular, Neurodegenerative, Aging-Related, and Immunoinflammatory Diseases

Effects of high dose olive leaf extract on haemodynamic and oxidative stress parameters in normotensive and spontaneously hypertensive rats

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