Oleuropein

Oleuropein at a Glance

Oleuropein is the principal secoiridoid glycoside of olive (Olea europaea) — the marquee polyphenol of olive leaf and the compound that standardised olive-leaf extracts are measured by. It is an ester of the phenol hydroxytyrosol and elenolic acid carrying a glucose unit, and it is the bitter principle of the olive: the reason a fresh olive off the tree is inedibly bitter and must be cured before eating.

It sits at the centre of olive leaf’s reputation as a cardiovascular and metabolic tonic. The best human evidence — for lowering blood pressure and improving insulin sensitivity — comes from standardised olive-leaf extract, in which oleuropein is the headline marker rather than the sole active. Isolated oleuropein and its aglycone carry a broad preclinical profile (antioxidant, anti-inflammatory, cardioprotective, neuroprotective, antimicrobial), but that work is overwhelmingly in cells and animals ^{1,8,12,14Reference 1Qabaha K et al. · 2018Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf ExtractView study →Reference 8Manna C et al. · 2004Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusionView study →Reference 12Bisignano G et al. · 1999On the in-vitro antimicrobial activity of oleuropein and hydroxytyrosolView study →Reference 14Casamenti F et al. · 2015AnimalOleuropein aglycone: a possible drug against degenerative conditionsView study →}.

The honest posture for this molecule is that marker is not isolate, and glycoside is not metabolite. Oleuropein is poorly absorbed intact and is largely hydrolysed to hydroxytyrosol, the smaller phenol that carries much of the measurable antioxidant activity and shows up in blood and urine after a dose ^{16,19Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}. As a constituent of a food eaten for millennia, it carries a reassuring safety profile at dietary and supplemental levels ^{25Reference 25Clewell AE et al. · 2016A comprehensive toxicological safety assessment of an extract of Olea europaea L. leaves (Bonolive)View study →}.

Oleuropein & Hydroxytyrosol

The single most useful fact about oleuropein is that it is a pro-molecule. Chemically it is hydroxytyrosol esterified to elenolic acid with an attached glucose; break those bonds and you liberate hydroxytyrosol, the small catechol phenol that carries a large share of olive polyphenols’ antioxidant power ^{19,20Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →Reference 20Yuan JJ et al. · 2015Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activitiesView study →}. This hydrolysis happens by several routes — the plant’s own β-glucosidase and esterase enzymes, gut microbiota, food processing, and simple acid/heat — so what a body actually sees after swallowing oleuropein is mostly its breakdown products, not the intact glycoside ^{16,19Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}.

The same reaction is the chemistry of curing olives. A fresh olive is bitter because it is loaded with oleuropein; debittering (lye treatment, brining and fermentation) hydrolyses that oleuropein away, and in naturally-fermented green olives it is the fruit’s own endogenous β-glucosidase and esterase that do the work — heating the fruit to inactivate those enzymes blocks debittering, proving the enzymatic route ^{19Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}. Enzymatic hydrolysis of olive-leaf oleuropein can convert nearly all of it (~98%) to hydroxytyrosol in vitro, which is why processed and stored olive products tend to be lower in oleuropein and richer in hydroxytyrosol than the fresh leaf or fruit ^{20Reference 20Yuan JJ et al. · 2015Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activitiesView study →}.

For the page this matters twice over: it means hydroxytyrosol is effectively the active metabolite of ingested oleuropein, and it means an olive-leaf product’s oleuropein number tells you about the starting material, not necessarily about what reaches the tissues.

The Olive-Leaf Extract Question

Olive leaf’s marquee human claims — modest blood-pressure lowering and improved insulin sensitivity — rest on standardised olive-leaf extract, not pure oleuropein. In the twin study, the captopril-comparison trial and the crossover BP/lipids trial, the intervention was a whole phenolic extract standardised to oleuropein (and co-delivering hydroxytyrosol, oleacein, ligstroside, flavonoids and triterpenes), dosed as milligrams of extract ^{2,3,4Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 4Perrinjaquet-Moccetti T et al. · 2008Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twinsView study →}. Oleuropein is the quality marker used to size and label those extracts; it is not the thing that was isolated and tested on its own.

This distinction is load-bearing because the extract’s activity is not reducible to oleuropein. A telling example is ACE inhibition: in bioassay-guided fractionation of olive, the potent ACE inhibitor is oleacein (IC50 ≈ 26 µM), while the secoiridoid glycosides including oleuropein show little ACE inhibition until they are hydrolysed ^{7Reference 7Hansen K et al. · 1996Isolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lanceaView study →}. So part of the extract’s blood-pressure effect is carried by a different secoiridoid, and part of oleuropein’s own contribution only appears after it breaks down. Read every human olive-leaf result here as an extract result standardised to oleuropein — the closest thing to an “oleuropein trial” in humans, but not the same as dosing the isolate.

What It's Used For

Oleuropein’s evidence base splits cleanly: human data are the extract (blood pressure, glycaemia), while the mechanistic, cardioprotective, neuroprotective and antimicrobial work is isolated oleuropein or its aglycone in cells and animals ^{1,8,14Reference 1Qabaha K et al. · 2018Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf ExtractView study →Reference 8Manna C et al. · 2004Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusionView study →Reference 14Casamenti F et al. · 2015AnimalOleuropein aglycone: a possible drug against degenerative conditionsView study →}.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. The two human-scored rows are the extract standardised to oleuropein, not the isolate; read the per-row basis.

01Antihypertensive (olive-leaf extract)Promising54%Multiple human RCTs of standardised extract; one comparable to captopril ^{2,3,4Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 4Perrinjaquet-Moccetti T et al. · 2008Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twinsView study →}

02Antidiabetic / metabolic (extract)Promising46%Human RCT (insulin sensitivity) + human/rat glucose data + isolate enzyme inhibition ^{9,10,11Reference 9de Bock M et al. · 2013RCTOlive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trialView study →Reference 10Wainstein J et al. · 2012AnimalOlive leaf extract as a hypoglycemic agent in both human diabetic subjects and in ratsView study →Reference 11Hadrich F et al. · 2015The α-glucosidase and α-amylase enzyme inhibitory of hydroxytyrosol and oleuropeinView study →}

03Antioxidant / anti-inflammatoryShaky38%Isolate identified as leaf’s principal anti-inflammatory; radical scavenging via hydroxytyrosol ^{1,24Reference 1Qabaha K et al. · 2018Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf ExtractView study →Reference 24Lins PG et al. · 2018In vitroIn vitro antioxidant activity of olive leaf extract (Olea europaea L.) and its protective effect on oxidative damage in human erythrocytesView study →}

04Cardioprotective / vascularShaky34%Isolate/enriched-extract: NO-dependent vasodilation, ischaemia-reperfusion protection ^{5,6,8Reference 5Romero M et al. · 2016AnimalAntihypertensive effects of oleuropein-enriched olive leaf extract in spontaneously hypertensive ratsView study →Reference 6Ilic S et al. · 2021AnimalEffects of oleuropein on rat’s atria and thoracic aorta: a study of antihypertensive mechanismsView study →Reference 8Manna C et al. · 2004Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusionView study →}

05NeuroprotectiveShaky28%Oleuropein aglycone ↓ amyloid-β, restores autophagy in AD-model mice ^{14,15Reference 14Casamenti F et al. · 2015AnimalOleuropein aglycone: a possible drug against degenerative conditionsView study →Reference 15Rigacci S · 2016Potential therapeutic effects of oleuropein aglycone in Alzheimer’s diseaseView study →}

06Antimicrobial / antiviralShaky24%In-vitro antibacterial; blocks HBsAg secretion, ↓ duck viraemia ^{12,13Reference 12Bisignano G et al. · 1999On the in-vitro antimicrobial activity of oleuropein and hydroxytyrosolView study →Reference 13Zhao G et al. · 2009Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorumView study →}

Mechanisms

The load-bearing subtlety is the ACE row: olive’s popular “natural ACE-inhibitor” billing is carried mostly by oleacein, and oleuropein’s own vascular effect runs through NO and antioxidant routes — one more reason the extract’s effect is not simply oleuropein’s ^{7Reference 7Hansen K et al. · 1996Isolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lanceaView study →}.

Pharmacokinetics

Oleuropein is a large, polar glycoside, and its defining PK fact is low intact oral bioavailability. In humans given olive-leaf extract, plasma intact oleuropein is very low (sub-ng to low-ng/mL) and the primary recovered species in plasma and urine are conjugated metabolites of hydroxytyrosol — i.e. the body absorbs and circulates the breakdown product far more than the parent glycoside ^{16Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →}. Hydrolysis to hydroxytyrosol happens presystemically (gut enzymes and microbiota) and the resulting hydroxytyrosol is itself matrix-dependent — its absorption and urinary recovery are higher from an oil matrix than from water or capsules ^{18Reference 18Alemán-Jiménez C et al. · 2021Pharmacokinetics and bioavailability of hydroxytyrosol are dependent on the food matrix in humansView study →}. Two practical consequences: (1) the “active” exposure after an oleuropein dose is substantially hydroxytyrosol and its conjugates (homovanillic acid, hydroxytyrosol sulfate, DOPAC), not oleuropein ^{16Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →}; and (2) an olive-leaf product’s oleuropein content describes the raw material, while what reaches tissues depends on hydrolysis and formulation ^{18,19Reference 18Alemán-Jiménez C et al. · 2021Pharmacokinetics and bioavailability of hydroxytyrosol are dependent on the food matrix in humansView study →Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}. Robust isolated-oleuropein human PK (Cmax, half-life, absolute bioavailability of the pure compound) is not well established — the human data are the extract.

Clinical Trials

Human evidence is entirely standardised olive-leaf extract standardised to oleuropein, not the isolate. Randomised controlled trials support modest blood-pressure lowering (one comparable to captopril) ^{2,3,4Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 4Perrinjaquet-Moccetti T et al. · 2008Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twinsView study →} and improved insulin sensitivity ^{9Reference 9de Bock M et al. · 2013RCTOlive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trialView study →}; an acute crossover found olive-leaf secoiridoids improved vascular function and lowered an inflammatory cytokine ^{17Reference 17Lockyer S et al. · 2015RCTSecoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, double-blind, placebo-controlled, cross-over trialView study →}. There are no controlled efficacy trials of isolated oleuropein as a drug.

Last checked: July 2026.

Isolate vs. Plant Studies

Oleuropein is a textbook case of marker-versus-isolate divergence. The human efficacy evidence is a plant extract: olive-leaf extract standardised to oleuropein, tested for blood pressure and glycaemia, co-delivering oleacein, hydroxytyrosol, ligstroside, flavonoids and triterpenes ^{2,3,9Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 9de Bock M et al. · 2013RCTOlive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trialView study →}. Because the extract’s most potent ACE inhibition is oleacein’s ^{7Reference 7Hansen K et al. · 1996Isolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lanceaView study →} and much of its antioxidant activity is hydroxytyrosol’s ^{20Reference 20Yuan JJ et al. · 2015Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activitiesView study →}, the whole-leaf result cannot be assigned to oleuropein alone.

The isolated-molecule evidence, by contrast, is preclinical — the NO-dependent vasodilation on rat vessels ^{6Reference 6Ilic S et al. · 2021AnimalEffects of oleuropein on rat’s atria and thoracic aorta: a study of antihypertensive mechanismsView study →}, the ischaemia-reperfusion cardioprotection ^{8Reference 8Manna C et al. · 2004Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusionView study →}, the aglycone’s amyloid-clearing action in Alzheimer mice ^{14Reference 14Casamenti F et al. · 2015AnimalOleuropein aglycone: a possible drug against degenerative conditionsView study →}, the antibacterial and anti-HBV activity ^{12,13Reference 12Bisignano G et al. · 1999On the in-vitro antimicrobial activity of oleuropein and hydroxytyrosolView study →Reference 13Zhao G et al. · 2009Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorumView study →}, and the identification of oleuropein as olive leaf’s principal anti-inflammatory constituent ^{1Reference 1Qabaha K et al. · 2018Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf ExtractView study →}. The correct framing is therefore: meaningful clinical evidence for the extract + a broad preclinical profile for the isolate/aglycone, connected — but not identical — through the shared chemistry of hydrolysis to hydroxytyrosol ^{16,19Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}.

Its Role in Plants

Oleuropein is a product of the secoiridoid branch of the terpenoid pathway in Oleaceae: geraniol-derived monoterpene precursors are elaborated through the oleoside/secologanin route to the secoiridoid glycosides, of which oleuropein is the dominant member in Olea europaea. The plant enzyme oleuropein β-glucosidase (OeGLU) is central to this secoiridoid metabolism — silencing it in olive abolishes the plant’s secoiridoid biosynthetic capacity ^{21Reference 21Koudounas K et al. · 2021Silencing of oleuropein β-glucosidase abolishes the biosynthetic capacity of secoiridoids in olivesView study →}.

Functionally, oleuropein is a defence and deterrence compound. It is intensely bitter — the bitter principle of the olive — and that bitterness, together with the reactive aldehydes released when the β-glucosidase acts on it after tissue damage, deters herbivores and inhibits microbes. Its concentration is highest in the youngest, most vulnerable tissues (young leaves and unripe fruit) and falls as the fruit ripens, consistent with a protective role that is dialled back once seeds mature ^{19,22,23Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →Reference 22Omar SH · 2010Oleuropein in olive and its pharmacological effectsView study →Reference 23Omar SH · 2010Cardioprotective and neuroprotective roles of oleuropein in oliveView study →}.

Prevalence in Nature

Oleuropein is the signature secoiridoid of the olive and, more broadly, a marker of the family Oleaceae. It is richest in olive leaf, reported at roughly 60–90 mg/g of dry matter (~6–9%), with commercial and cultivar extremes cited up to ~14% ^{22Reference 22Omar SH · 2010Oleuropein in olive and its pharmacological effectsView study →}; independent measurements on particular leaf samples run lower (e.g. ~25 mg/g), underscoring how much cultivar, season, plant part, drying and extraction move the number ^{24Reference 24Lins PG et al. · 2018In vitroIn vitro antioxidant activity of olive leaf extract (Olea europaea L.) and its protective effect on oxidative damage in human erythrocytesView study →}. In the fruit it can reach up to ~140 mg/g dry matter in young, unripe olives and then declines steeply during ripening as it hydrolyses toward hydroxytyrosol — the chemical basis of both curing and the low oleuropein of ripe/processed olives ^{19,23Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →Reference 23Omar SH · 2010Cardioprotective and neuroprotective roles of oleuropein in oliveView study →}.

Beyond Olea, oleuropein and related secoiridoids occur across other Oleaceae genera — privet (Ligustrum), jasmine (Jasminum), ash (Fraxinus) and lilac (Syringa) — which is why it recurs in the phytochemistry of several unrelated-seeming herbs; the jasmine anti-HBV isolate came from J. officinale var. grandiflorum ^{13,22Reference 13Zhao G et al. · 2009Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorumView study →Reference 22Omar SH · 2010Oleuropein in olive and its pharmacological effectsView study →}.

Major Natural Sources

Source	Plant part	Reported oleuropein content
Olive leaf (Olea europaea)	leaf	~60–90 mg/g dry wt (~6–9%; up to ~14%)
Olive fruit (Olea europaea)	unripe green fruit	up to ~140 mg/g dry wt (falls with ripening)
Olive fruit (Olea europaea)	ripe / cured	low (hydrolysed away by curing)

These are dry-matter figures for the plant tissue and vary widely with cultivar, season and processing ^{19,22,23Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →Reference 22Omar SH · 2010Oleuropein in olive and its pharmacological effectsView study →Reference 23Omar SH · 2010Cardioprotective and neuroprotective roles of oleuropein in oliveView study →}.

Discovery & Synthesis

Oleuropein was first isolated and named in 1908 by the French pharmacists Émile Bourquelot and Constantin Vintilesco, who described it as a new glucosidic principle of the olive (Olea europaea) — the source of both its name (from the genus Olea) and its identity as the olive’s bitter glycoside. (This is a pre-PubMed primary source, consistently reported across the modern reviews but not verifiable here to an original digitised copy.)

Unlike many aroma and phenolic molecules that moved to industrial synthesis, oleuropein is obtained by extraction — chiefly from olive leaf, an abundant by-product of olive cultivation and pruning — rather than by commercial total synthesis. Standardised olive-leaf extracts are produced by aqueous/hydroalcoholic extraction and standardised to an oleuropein percentage, and much industrial interest is actually in the downstream step: converting extracted oleuropein to hydroxytyrosol (the higher-value antioxidant) by controlled enzymatic hydrolysis ^{20Reference 20Yuan JJ et al. · 2015Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activitiesView study →}.

Patents: not yet researched.

Toxicity & Safety

Oleuropein carries a low toxicity flag. It is a constituent of a food humans have eaten for millennia — olives and, in small amounts, olive oil — and both it and its metabolite hydroxytyrosol have a long dietary history. A comprehensive toxicological assessment of a standardised olive-leaf extract (Bonolive) found a 90-day rat NOAEL at the highest dose tested, 1000 mg/kg/day, with negative results across the Ames, chromosomal-aberration and micronucleus genotoxicity tests ^{25Reference 25Clewell AE et al. · 2016A comprehensive toxicological safety assessment of an extract of Olea europaea L. leaves (Bonolive)View study →}. The practical cautions are pharmacological rather than toxicological.

Safety at a Glance

✅ Low / no toxicity

• Low-toxicity food constituent. A polyphenol of olives with a long dietary history; standardised olive-leaf extract showed a 90-day rat NOAEL at the top dose (1000 mg/kg/day) and no genotoxicity ^{25Reference 25Clewell AE et al. · 2016A comprehensive toxicological safety assessment of an extract of Olea europaea L. leaves (Bonolive)View study →}.
• Additive blood-pressure lowering. Olive-leaf extract lowers BP; combined with antihypertensive drugs it may compound the effect — relevant to anyone on BP or cardiovascular medication ^{2,3Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →}.
• Marker ≠ isolate. Human safety and efficacy data are for the whole extract standardised to oleuropein, not the pure compound; do not read extract results as pure-oleuropein results.
• Metabolite, not parent. Most absorbed activity is hydroxytyrosol and its conjugates; oleuropein itself is poorly absorbed intact ^{16Reference 16de Bock M et al. · 2013Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extractView study →}.

Pregnancy and lactation are per-herb / per-supplement decisions and are not adjudicated on this molecule page; dedicated human reproductive data for isolated oleuropein are limited, and no isolate-specific verdict is issued here.

Dosage

There is no established dose for isolated oleuropein. The human evidence is for standardised olive-leaf extract, commonly dosed at 500–1000 mg extract/day in trials — delivering roughly 50–140 mg oleuropein/day depending on the standardisation — for blood pressure and metabolic endpoints ^{2,3,4,9Reference 2Susalit E et al. · 2011Clinical trialOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captoprilView study →Reference 3Lockyer S et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 4Perrinjaquet-Moccetti T et al. · 2008Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twinsView study →Reference 9de Bock M et al. · 2013RCTOlive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trialView study →}.

These are extract figures standardised to oleuropein and research doses, not a recommendation for the pure compound. Dietary exposure comes from olives (much reduced by curing) and, in small amounts, olive oil ^{18,19Reference 18Alemán-Jiménez C et al. · 2021Pharmacokinetics and bioavailability of hydroxytyrosol are dependent on the food matrix in humansView study →Reference 19Ramírez E et al. · 2016Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymesView study →}.

References

1. Qabaha K, et al. (2018). Oleuropein Is Responsible for the Major Anti-Inflammatory Effects of Olive Leaf Extract. Journal of Medicinal Food. https://pubmed.ncbi.nlm.nih.gov/29099642/
2. Susalit E, et al. (2011). Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with captopril. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/21036583/
3. Lockyer S, et al. (2017). Impact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial. European Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/26951205/
4. Perrinjaquet-Moccetti T, et al. (2008). Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins. Phytotherapy Research. https://pubmed.ncbi.nlm.nih.gov/18729245/
5. Romero M, et al. (2016). Antihypertensive effects of oleuropein-enriched olive leaf extract in spontaneously hypertensive rats. Food & Function. https://pubmed.ncbi.nlm.nih.gov/26593388/
6. Ilic S, et al. (2021). Effects of oleuropein on rat’s atria and thoracic aorta: a study of antihypertensive mechanisms. Canadian Journal of Physiology and Pharmacology. https://pubmed.ncbi.nlm.nih.gov/33449845/
7. Hansen K, et al. (1996). Isolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lancea. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/23194770/
8. Manna C, et al. (2004). Oleuropein prevents oxidative myocardial injury induced by ischemia and reperfusion. Journal of Nutritional Biochemistry. https://pubmed.ncbi.nlm.nih.gov/15302080/
9. de Bock M, et al. (2013). Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PLoS One. https://pubmed.ncbi.nlm.nih.gov/23516412/
10. Wainstein J, et al. (2012). Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats. Journal of Medicinal Food. https://pubmed.ncbi.nlm.nih.gov/22512698/
11. Hadrich F, et al. (2015). The α-glucosidase and α-amylase enzyme inhibitory of hydroxytyrosol and oleuropein. Journal of Oleo Science. https://pubmed.ncbi.nlm.nih.gov/26235001/
12. Bisignano G, et al. (1999). On the in-vitro antimicrobial activity of oleuropein and hydroxytyrosol. Journal of Pharmacy and Pharmacology. https://pubmed.ncbi.nlm.nih.gov/10504039/
13. Zhao G, et al. (2009). Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorum. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/19580857/
14. Casamenti F, et al. (2015). Oleuropein aglycone: a possible drug against degenerative conditions. In vivo evidence of its effectiveness against Alzheimer’s disease. Journal of Alzheimer’s Disease. https://pubmed.ncbi.nlm.nih.gov/25649656/
15. Rigacci S (2016). Potential therapeutic effects of oleuropein aglycone in Alzheimer’s disease. Current Pharmaceutical Biotechnology. https://pubmed.ncbi.nlm.nih.gov/27455905/
16. de Bock M, et al. (2013). Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extract. Molecular Nutrition & Food Research. https://pubmed.ncbi.nlm.nih.gov/23766098/
17. Lockyer S, et al. (2015). Secoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, double-blind, placebo-controlled, cross-over trial. British Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/26051429/
18. Alemán-Jiménez C, et al. (2021). Pharmacokinetics and bioavailability of hydroxytyrosol are dependent on the food matrix in humans. European Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/32524230/
19. Ramírez E, et al. (2016). Oleuropein hydrolysis in natural green olives: importance of the endogenous enzymes. Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/27041317/
20. Yuan JJ, et al. (2015). Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activities. Molecules. https://pubmed.ncbi.nlm.nih.gov/25679050/
21. Koudounas K, et al. (2021). Silencing of oleuropein β-glucosidase abolishes the biosynthetic capacity of secoiridoids in olives. Frontiers in Plant Science. https://pubmed.ncbi.nlm.nih.gov/34539687/
22. Omar SH (2010). Oleuropein in olive and its pharmacological effects. Scientia Pharmaceutica. https://pubmed.ncbi.nlm.nih.gov/21179340/
23. Omar SH (2010). Cardioprotective and neuroprotective roles of oleuropein in olive. Saudi Pharmaceutical Journal. https://pubmed.ncbi.nlm.nih.gov/23964170/
24. Lins PG, et al. (2018). In vitro antioxidant activity of olive leaf extract (Olea europaea L.) and its protective effect on oxidative damage in human erythrocytes. Heliyon. https://pubmed.ncbi.nlm.nih.gov/30255162/
25. Clewell AE, et al. (2016). A comprehensive toxicological safety assessment of an extract of Olea europaea L. leaves (Bonolive). International Journal of Toxicology. https://pubmed.ncbi.nlm.nih.gov/26658007/

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