The Science

Scientific Articles About Olive Leaf Extract

Olive Leaf and Full Spectrum Healing:

1. Oleuropein in Olive and its Pharmacological Effects: “The present review focuses on recent works that have analyzed the relationship between the major phenolic compound oleuropein and its pharmacological activities including antioxidant, anti-inflammatory, anti-atherogenic, anti-cancer activities, antimicrobial activity, antiviral activity, hypolipidemic and hypoglycemic effect.”

Olive Leaf and High Blood Pressure:

1. Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension comparison with Captopril: “In conclusion, Olive (Olea europaea) leaf extract, at the dosage regimen of 500 mg twice daily, was similarly effective in lowering systolic and diastolic blood pressures in subjects with stage-1 hypertension as Captopril, given at its effective dose of 12.5-25 mg twice daily.”

2. A clinical trial of a titrated Olea extract in the treatment of essential arterial hypertension:  “We note for all patients a statistically significant decrease of blood pressure.”

3. Blood pressure lowering effect of an olive leaf extract (Olea europaea)… “The findings confirm previous reports on the hypotensive (lowering of blood pressure) effects of olive leaf.”

4. Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins: “Concluding, the study confirmed the antihypertensive and cholesterol-lowering action of EFLA943 (olive leaf extract) in humans.”

5. Olive Leaf Safely Modulates Blood Pressure:

6. Antithrombotic effect of repeated doses of the ethanolic extract of local olive (Olea europaea L.) leaves: “The incidence of thromboembolic diseases is increasing, and they are a major cause of mortality and morbidity worldwide. Mediterranean diet is known for its high content of olive products, especially olive oil, which has known cardiovascular health benefits, including those on blood pressure, cholesterol level, and thrombogenesis. All previous animal and clinical studies investigating the beneficial antithrombotic effects of olives have focused on olive oil and a few on olive leaves (OLEs). In this study, the ethanolic extract of OLE was evaluated for its antithrombotic activity in the rabbit model of thrombosis induced by ligature of the vena cava and intravenous administration of tissue thromboplastin… One important finding in this study concerns thrombus morphology. In the extract treatment groups, the thrombus was filament-like and did not adhere to blood vessel walls, whereas in the control group the thrombus was thick and almost completely occluded the vein. Therefore, these results suggest that OLE (Olive Leaf Extract) ethanolic extract can modify the extrinsic coagulation pathway as evidenced by the prolongation of PT and changes in thrombus morphology.”

7. The effects of polyphenols in olive leaves on platelet function: “The phenolic compounds of olive leaves and olive oils in the Mediterranean diet have been associated with a reduced incidence of heart disease. Accordingly, antioxidant-rich diets may prevent the deleterious effects of oxidative metabolism by scavenging free radicals, thus inhibiting oxidation and delaying atherosclerosis… Olive leaf polyphenols derived from O. europaea L. leaves inhibited in vitro platelet activation in healthy, non-smoking males.”

8. Antihypertensive, antiatherosclerotic and antioxidant activity of triterpenoids isolated from Olea europaea, subspecies africana leaves: “All three isolates, in a dose 60 mg/kg b.w. for 6 weeks treatment, prevented the development of severe hypertension and atherosclerosis and improved the insulin resistance of the experimental animals. GO, OA and CT isolates could provide an effective and cheap treatment of this particular, most common type of salt-sensitive hypertension in the African population.”

Olive Leaf and Diabetes:

1. Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats: ” Olive leaf extract is associated with improved glucose homeostasis in  humans. Animal models indicate that this may be facilitated through the reduction of starch digestion and absorption. Olive leaf extract may represent an effective adjunct therapy that normalizes glucose homeostasis in individuals with diabetes.”

2. Antidiabetic effect of Olea europaea: “A comparison was made between the action of olive leaves extract and glibenclamide (600 microg/kg), a known antidiabetic drug. The antidiabetic effect of the extract was more effective than that observed with glibenclamide.”

3. Olive (Olea europaea L.) leaf extract attenuates early diabetic neuropathic pain through prevention of high glucose-induced apoptosis: in vitro and in vivo studies: “The results suggest that olive leaf extract inhibits high glucose-induced neural damage and suppresses diabetes-induced thermal hyperalgesia. The mechanisms of these effects may be due, at least in part, to reduce neuronal apoptosis and suggest therapeutic potential of oliveleaf extract in attenuation of diabetic neuropathic pain.”

4.  Study Finds Olive Leaf Extract Useful in Diabetes Management.

5. Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial: “Supplementation with olive leaf polyphenols for 12 weeks significantly improved insulin sensitivity and pancreatic β-cell secretory capacity in overweight middle-aged men at risk of developing the metabolic syndrome.”

6. Dried leaf extract of Olea europaea ameliorates islet-directed (Diabetic) autoimmunity…:  “The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly associated with hypoglycaemic and insulin-sensitising activities and have been widely demonstrated in the metabolic syndrome and type 2 diabetes… The results suggest that DOLE (Dried Olive Leaf Extract) interferes with development of autoimmune diabetes by down-regulating production of proinflammatory and cytotoxic mediators. Therefore, the potential use of a DOLE ((Dried Olive Leaf Extract)-enriched diet for prophylaxis/treatment of human T1D (Type 1 Diabetes), and possibly other autoimmune diseases, is worthy of further investigation.

Olive Leaf and Viruses, Bacteria and Fungal Infections:

1. The olive leaf extract exhibits antiviral activity against viral haemorrhagic septicaemia rhabdovirus (VHSV): “Therefore, we propose that O. europaea could be used as a potential source of promising natural antivirals, which have demonstrated to lack impact on health and environment. In addition, Ole could be used to design other related antiviral agents.”

2.  Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment: “We investigated the antiviral activity of olive leaf extract (OLE) preparations standardized by liquid chromatography-coupled mass spectrometry (LC-MS) against HIV-1 infection and replication. We find that OLE inhibits acute infection and cell-to-cell transmission of HIV-1 as assayed by syncytia formation using uninfected MT2 cells co-cultured with HIV-1-infected H9 T lymphocytes. OLE also inhibits HIV-1 replication as assayed by p24 expression in infected H9 cells… Treatment with OLE reverses many of these HIV-1 infection-associated changes. Treatment of HIV-1-infected cells with OLE also up-regulates the expression of the apoptosis inhibitor proteins IAP1 and 2, as well as the calcium and protein kinase C pathway signaling molecules IL-2, IL-2Ralpha, and ornithine decarboxylase ODC1.”

3. In vitro antimicrobial activity of olive leaves: “We investigated the antimicrobial effect of olive leaves against bacteria and fungi. The microorganisms tested were inoculated in various concentrations of olive leaf water extract. Olive leaf 0.6% (w/v) water extract killed almost all bacteria tested, within 3 hours.”

4. Olive Leaf: Discover the worlds most potent natural herpes cure, along with other extremely effective home remedies for herpes in this “must read” article – See more at:

5.  Olive Leaf: The Miracle Supplement That Fights Herpes.

6.  Olive Leaf Extract for viruses, bacterial, fungal infections and mosquito born parasites such as malaria or dengue: A New/Old Healing Bonanza for Mankind by James R. Privitera, M.D.:

7. Activity assessment of Tunisian olive leaf extracts against the trophozoite stage of Acanthamoeba: “Trophozoite growth was inhibited by all the tested extracts…”

8.  Antimicrobial activity of commercial Olea europaea (olive) leaf extract: “Given this specific activity, olive leaf extract may have a role in regulating the composition of the gastric flora by selectively reducing levels of H. pylori and C. jejuni.”

9.  Phenolic compounds and antimicrobial activity of olive (Olea europaea L. Cv. Cobrançosa) leaves: “At low concentrations olive leaves extracts showed an unusual combined antibacterial and antifungal action, which suggest their great potential as nutraceuticals, particularly as a source of phenolic compounds.”

10. Hydroxytyrosol expresses antifungal activity in vitro: “Hydroxytyrosol (HT) is a potent antioxidant found in olive oil and leaves. Using several in vitro approaches, we tested antifungal activity of HT. HT showed broad spectrum of antifungal activity against medically important yeasts…”

11. Leishmanicidal activity assessment of olive tree extracts: “Leishmaniasis, a protozoan parasitic disease that remains a major worldwide health problem with high endemicity in developing countries, is prevalent around the Mediterranean basin. High cost, systemic toxicity, and diminished efficacy due to development of parasite resistance are the serious drawbacks of current treatment options… Oleuropein and hydroxytyrosol exhibited the best inhibitory effect among the natural products tested in both stationary and middle logarithmic phase promastigotes of L. infantum, L. donovani, and L. major. Similarly, oleuropein and hydroxytyrosol demonstrated the highest selectivity index ratio against L. donovani amastigotes that parasitize J774A.1 macrophages…Three days after treatment termination, the spleen parasitic burden was reduced >80%. Of interest, this effect of oleuropein persisted and was even enhanced 6 weeks after the termination of the treatment, as determined by parasite depletion of >95% in liver and spleen. These findings contribute to the potential development of natural products as effective drugs against parasites of the Leishmania genus, with low cost and diminished cytotoxicity.”

12. Antioxidant and antimicrobial activities of individual and combined phenolics in Olea europaea leaf extract: “These results show that the combination of olive leaf extract phenolics possessed antioxidant and antimicrobial activities. This study indicates that olive leaf extract might be a valuable bioactive source, and would seem to be applicable in both the health and medical food.”

Olive Leaf and Cancer/Tumors:

1. Olive Leaf’s Active Ingredient, Oleuropein, a non-toxic olive iridoid, is an anti-tumor agent…: “Oleuropein, a non-toxic secoiridoid derived from the olive tree, is a powerful antioxidant and anti-angiogenic agent. Here, we show it to be a potent anti-cancer compound, directly disrupting actin filaments in cells and in a cell-free assay. Oleuropein inhibited the proliferation and migration of advanced-grade tumor cell lines in a dose-responsive manner. In a novel tube-disruption assay, Oleuropein irreversibly rounded cancer cells, preventing their replication, motility, and invasiveness; these effects were reversible in normal cells. When administered orally to mice that developed spontaneous tumors, Oleuropein completely regressed tumors in 9-12 days. When tumors were resected prior to complete regression, they lacked cohesiveness and had a crumbly consistency. No viable cells could be recovered from these tumors. These observations elevate Oleuropein from a non-toxic antioxidant into a potent anti-tumor agent with direct effects against tumor cells. Our data may also explain the cancer-protective effects of the olive-rich Mediterranean diet.”

2. Olive Leaf’s Active Ingredient, Oleuropein, a secoiridoid derived from olive tree, inhibits the proliferation of human colorectal cancer cell through downregulation of HIF-1α: “Our novel findings demonstrate that Olive Leaf limits the growth and induces apoptosis in HT-29 cells via p53 pathway activation adapting the HIF-1α response to hypoxia.”

3. Olive Leaf Extract Benefits Shown to Eliminate Cancer Tumors By Oleropein: Read more:

4.  Multiple antimelanoma potential of dry olive leaf extract: “The anticancer potential of dry olive leaf extract (DOLE) represents the net effect of multilevel interactions between different biologically active compounds from the extract, cancer cells and conventional therapy.”

5. Olive oil oleuropein has anti-breast cancer properties with higher efficiency on ER-negative cells: ” Indeed, oleuropein exhibits specific cytotoxicity against breast cancer cells, with higher effect on the basal-like MDA-MB-231 cells than on the luminal MCF-7 cells. This effect is mediated through the induction of apoptosis via the mitochondrial pathway. Moreover, oleuropein inhibits cell proliferation by delaying the cell cycle at S phase and up-regulated the cyclin-dependent inhibitor p21. Furthermore, oleuropein inhibited the anti-apoptosis and pro-proliferation protein NF-κB and its main oncogenic target cyclin D1. This inhibition could explain the great effect of oleuropein on cell proliferation and cell death of breast cancer cells. Therefore, oleuropein warrants further investigations to prove its utility in preventing/treating breast cancer, especially the less-responsive basal-like type.”

6.  A pilot study on the DNA-protective, cytotoxic, and apoptosis-inducing properties of olive-leaf extracts: “In the present study, the principal bioactive phenols in olive-leaf extracts (OLEs) have been identified and quantified, and their genotoxic/antigenotoxic, cytotoxic and apoptotic effects have been assessed…DNA fragmentation patterns and cell staining with acridine orange and ethidium bromide indicated that the mechanism for the cytotoxic effect of OLE, oleuropein and luteolin was the apoptotic pathway, with DNA laddering and cytoplasmic and nuclear changes. These results could help explain the mechanism of action that underlies the beneficial effect of OLE, proposed as a nutraceutical in the prevention of human cancer.”

7. Hydroxytyrosol rich extract from olive leaves modulates cell cycle progression in MCF-7 human breast cancer cells: “In this work, a hydroxytyrosol rich olive leaves extract was investigated for potential anti-tumoral activities… In vitro cytotoxic effects against MCF-7 breast cancer cells were examined using MTT and neutral red tests. The anti-tumor activities were further investigated by flow cytometry and western blotting. Cytotoxicity assays resulted in a dose dependent growth inhibition of MCF-7 cells. This inhibition was due to the cell cycle arrest in the G0/G1 phase. The understanding of the molecular mechanism by which olive leaves extract arrested cell growth showed a down-expression of the peptidyl-prolyl cis-trans isomerase Pin1 which in turn decreased the level of a G1 key protein; Cyclin D1. Additionally, olive leaves extract treatment up-regulated the AP1 transcription factor member, c-jun. Therefore, olive leaves extract will necessitate further deep investigation for a probable use as a cancer preventive food additive.”

8. Qualitative screening of phenolic compounds in olive leaf extracts by hyphenated liquid chromatography and preliminary evaluation of cytotoxic activity against human breast cancer cells: “Importantly, olive leaf extracts exhibited dose-dependent inhibitory effects on the metabolic status (cell viability) of three breast cancer models in vitro. Since the tumoricidal activity of the extracts should be mainly attributed to the identified olive leaf phenolics, these findings warrant further investigation at the structure-function molecular level to definitely establish the anticancer value of these phytochemicals.”

9.  Induction of growth inhibition and differentiation of human leukemia HL-60 cells by a Tunisian gerboui olive leaf extract:  “The results showed significant growth inhibition of HL-60 (leukemia) cells incubated for 48 h with a 100-fold dilution of each OLE which had been obtained by incubating 10 g of dried leaves in 100 ml of 70% ethanol for one week with subsequent ultrafiltration.”

10. Anti-proliferative and apoptotic effects of oleuropein and hydroxytyrosol on human breast cancer MCF-7 cells: “Oleuropein or hydroxytyrosol decreased cell viability, inhibited cell proliferation, and induced cell apoptosis in MCF-7 cells. Result of MTT assay showed that 200 μg/mL of oleuropein or 50 μg/mL of hydroxytyrosol remarkably reduced cell viability of MCF-7 cells. Oleuropein or hydroxytyrosol decrease of the number of MCF-7 cells by inhibiting the rate of cell proliferation and inducing cell apoptosis. Also hydroxytyrosol and oleuropein exhibited statistically significant block of G1 to S phase transition manifested by the increase of cell number in G0/G1 phase.”

Olive Leaf and Pain:

1. Double-blind placebo-controlled trial of hydroxytyrosol of Olea europaea on pain in gonarthrosis: “Hydroxytyrosol is mainly found in olive leaves after hydrolysis of oleuropein and has anti-oxidant, anti-bacterial, and anti-inflammatory properties. The aim of this study was to investigate the effect of hydroxytyrosol for alleviating the pain in patients with gonarthrosis. We conducted a double-blind clinical trial in which hydroxytyrosol or placebo was administered to adult patients with gonarthrosis for 4 weeks. The group administered hydroxytyrosol showed significant improvement in the Japanese Orthopedic Association score (pain measurement index) and the visual analog scale score compared to the placebo group.”

Olive Leaf and Parkinson’s:

1. Inhibition of 6-hydroxydopamine-induced PC12 cell apoptosis by olive (Olea europaea L.) leaf extract is performed by its main component oleuropein: “Parkinson disease (PD) is the most common progressive neurodegenerative disorder characterized by progressive death of midbrain dopaminergic neurons. Most neurodegenerative disease treatments are, at present, palliative. However, some natural herbal products have been shown to rescue neurons from death and apoptosis in some of neurodegenerative diseases. Not only Olea europaea L. olive oil, but also the leaves of this plant have been used for medical purposes. Olive leaf extract (OLE) is being used by people as a drink across the world and as an integral ingredient in their desire to maintain and improve their health…The results suggest that OLE and oleuropein have anti-oxidant protective effects against 6-OHDA-induced PC12 cell damage. The protective effects of OLE and oleuropein are correlative with their anti-oxidative and anti-apoptotic properties and suggest their therapeutic potential in the treatment of PD.

Olive Leaf and Autoimmune Illnesses:

1. Dried leaf extract of Olea europaea ameliorates islet-directed (Diabetic) autoimmunity…: “The health-promoting effects of various constituents of the olive tree (Olea europaea) are mainly associated with hypoglycaemic and insulin-sensitising activities and have been widely demonstrated in the metabolic syndrome and type 2 diabetes… The results suggest that DOLE (Dried Olive Leaf Extract) interferes with development of autoimmune diabetes by down-regulating production of proinflammatory and cytotoxic mediators. Therefore, the potential use of a DOLE ((Dried Olive Leaf Extract)-enriched diet for prophylaxis/treatment of human T1D (Type 1 Diabetes), and possibly other autoimmune diseases, is worthy of further investigation.

2.  Dry olive leaf extract ameliorates experimental autoimmune encephalomyelitis: “The results presented in this paper strongly suggest that DOLE (Dry Olive Leaf Extract) -enriched diet has a beneficial effect in EAE in rats. Further studies in humans are required in order to investigate if DOLE could be a useful supplementary dietetic for the patients suffering from multiple sclerosis and other neuroinflammatory disorders.”

Olive Leaf and Inflammation:

1. Chloroformic and Methanolic Extracts of Olea Europaea L. Leaves Present Anti-Inflammatory and Analgesic Activities: “The chloroformic and methanolic leaves extracts, studied at the doses of 50, 100, and 200 mg/kg (Body Weight: BW), exhibited significant dose-dependent anti-inflammatory and analgesic activities. Based on the results obtained, it can be concluded that Olea europaealeaves extracts have anti-inflammatory and antinociceptive effects.”