Olive leaf extract (Olea europaea L.) contains oleuropein and the flavonoids apigenin,  luteolin, chrysoeriol, hesperidin, rutin, quercetin, and kaempferol. Major isolated constituents in olive leaf strongly inhibit the classical pathway of the complement system.

Full Spectrum Olive Leaf Extract, 825 mg, 60 Tabs - Planetary Formulas
Planetary Formulas Full Spectrum Olive Leaf Extract combines a concentrated olive leaf extract standardized to 15% of its key constituent, oleuropein, with a pure olive leaf concentrate.  Combining standardized extract with whole herb concentrate guarantees the presence of all primary and secondary compounds that give olive leaf its immune-supportive effects.

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Benefit of olive leaf extract
There have not been any good human studies with olive leaf extract to know which medical conditions it would benefit. Olive leaf extract is just beginning to be tested in humans so it may take some time until we find out the right dosage for the right condition. A study in rodents shows this herb may have blood pressure lowering effect.

Anti-inflammatory benefit
Most flavonoids in olive leaf extract have antiinflammatory properties

Immune system effect
Most flavonoids in olive leaf extract have anti-microbial activity. There are many supplements, herbs or herbal extracts that play a role in immune system support. A few of these include oregano oil supplement, colostrum supplement and Andrographis.

Diabetes and blood sugar
The hypoglycemic activity of olive leaf extract was studied. One of the compounds responsible for this activity was oleuropeoside, which showed activity at a dose of 16 mg/kg. This compound also demonstrated antidiabetic activity in animals with alloxan-induced diabetes.

HIV treatment
Olive leaf may have anti-HIV activity (see below).

Hypertension - does olive leaf extract lower blood pressure?
Q. I am currently working on a series on a TV series on Hypertension, new information has been published about the benefits of olive leaf extract, EFLA®943. I was wondering if you have any information about olive leaf extract, EFLA®943.
   A. A pilot trial completed in 2008 with 20 identical (monozygotic) twin pairs who had an increased blood pressure was conducted for a period of 20 weeks. Patients were either given placebo capsules or capsules containing doses of 500mg or 1000mg of olive leaf extract EFLA®943. Olive leaf extract EFLA®943 was able to lower blood pressure when used in the higher dosage. Blood pressure changed significantly within pairs, depending on the dose, with mean systolic differences of ≤ 6 mm Hg (500 mg vs. control) and ≤ 13 mm Hg (1000 vs. 500 mg), and diastolic differences of ≤ 5 mm Hg. After eight weeks, mean blood pressure remained unchanged from baseline in controls and the low-dose group, but had significantly decreased for the high-dose group. Cholesterol levels decreased for all treatments with significant dose-dependent, within-pair differences for low-density lipoprotein (LDL) cholesterol. Phytotherapy Research 2008;22:1239–1242.

Vascular dilation
Researchers studied the importance of the smooth vascular muscle endothelium in the vasodilator action of the decoction of olive leaf (Olea europaea). The decoction caused relaxation of isolated rat aorta preparations both in the presence and in the absence of endothelium. The results indicate that the relaxant activity of the lyophilized decoction is independent of the integrity of the vascular endothelium. We also showed that oleuropeoside is a component responsible for vasodilator activity but, from the results, it seems likely that at least one other principle is to be found in the olive leaf which is either a vasodilator itself or else potentiates the relaxant effect of oleuropeoside.

Olive leaf extract side effects, safety, danger
There have not been any side effects reported yet with olive leaf extract supplement, but few human studies are available.

Benefit of Olive Oil
Certain micronutrients contained in olive oil and other foods could be responsible for the Mediterranean diet's well known heart-healthy effects. These compounds, known as phenols, have been shown in laboratory studies to have antioxidant, anti-inflammatory and blood clot preventing powers. The intake of food high in phenols compounds could improve cardiovascular health and protect the heart," Jimenez told Reuters Health. "An example of these foods is virgin or extra virgin olive oil. Researchers compared the effect of consuming phenol-rich olive oil or olive oil with most of its phenol content removed in a group of 21 volunteers with high cholesterol. They measured the ability of the study participants' blood vessels to respond to rapid changes in blood flow after they had consumed a relatively high-fat meal containing either type of olive oil. Blood vessels have been shown to function poorly after a high-fat meal. Blood vessel response and function was improved for the first four hours after the high-phenol olive oil meal, but there was no difference in blood vessel function before and after volunteers ate the low-phenol olive oil meal. The researchers also found increased levels of the blood vessel dilating molecule nitric oxide and reduced levels of oxidative stress after consumption of the high-phenol meal. Consumers should reach for olive oils labeled "virgin" or "extra virgin," which have the highest phenol content.

Benefit of Extra Virgin Olive Oil
Virgin olive oil has a benefit over other vegetable fats. Virgin olive oil may be particularly effective at lowering heart disease risk because of its high level of antioxidant plant compounds. Virgin olive oil -- rich in antioxidants called polyphenols -- has stronger heart-health effects than the more extensively processed "non-virgin" variety. Polyphenols are likely to account for some of the health benefits that have been attributed to virgin olive oil. Virgin olive oil may be the only vegetable oil that's rich in polyphenols. All vegetable oils other than virgin olive oil are submitted to a (refining) process in which polyphenols are practically lost. Even "ordinary" olive oil has a lower polyphenol content because it's a mixture of virgin olive oil and a more-processed form of the oil. Annals of Internal Medicine, September 5, 2006.
   Eating foods prepared with olive oils that are rich in phenols, help ward off harmful blood clots in people with high cholesterol.

Olive oil and thrombosis
Virgin olive oil with a high content of phenolic compounds changes the postprandial hemostatic profile to a less thrombogenic state. This helps improve blood flow and reduces blood clotting.

Composition
Olive oil has mixed triglyceride esters of oleic acid and palmitic acid and of other fatty acids, along with traces of squalene and sterols. The composition varies by cultivar, region, altitude, time of harvest, and extraction process. Olive oil contains a group of related natural products with potent antioxidant properties that give extra-virgin unprocessed olive oil its bitter and pungent taste and are esters of tyrosol and hydroxytyrosol, including oleocanthal and oleuropein.

Benefit of Olive Leaf Extract Research
The olive leaf extract exhibits antiviral activity against viral haemorrhagic septicaemia rhabdovirus (VHSV).
Antiviral Res. 2005 Jun;66(2-3):129-36.
Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, E-03202-Elche, Alicante, Spain.
A commercial plant extract derived from olive tree leaf (Olea europaea) and its major compound, oleuropein, inhibited the in vitro infectivity of the viral haemorrhagic septicaemia virus (VHSV), a salmonid rhabdovirus. Incubation of virus with olive tree leaf extract or oleuropein before infection reduced the viral infectivity to 10 and 30%, respectively. Furthermore, olive tree leaf extractdrastically decreased VHSV titers and viral protein accumulation (virucidal effect) in a dose dependent manner when added to cell monolayers 36 h post-infection. On the other hand, both the olive tree leaf extract and oleuropein were able to inhibit cell-to-cell membrane fusion induced by VHSV in uninfected cells, suggesting interactions with viral envelope. Therefore, we propose that olive tree leaf extract could be used as a potential source of promising natural antivirals, which have demonstrated to lack impact on health and environment. In addition, oleuropein could be used to design other related antiviral agents.

Anti-HIV activity of olive leaf extract and modulation of host cell gene expression by HIV-1 infection and olive leaf extract treatment.
Lee-Huang S. ew York University School of Medicine, New York
Biochem Biophys Res Commun. 2003 Aug 8;307(4):1029-37.
We investigated the antiviral activity of olive leaf extract preparations standardized by liquid chromatography-coupled mass spectrometry (LC-MS) against HIV-1 infection and replication. We find that olive leaf extract 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. olive leaf extract also inhibits HIV-1 replication as assayed by p24 expression in infected H9 cells. These anti-HIV effects of olive leaf extract are dose dependent, with EC(50)s of around 0.2 microg/ml. In the effective dose range, no cytotoxicity on uninfected target cells was detected. The therapeutic index of olive leaf extract is above 5000. To identify viral and host targets for olive leaf extract, we characterized gene expression profiles associated with HIV-1 infection and olive leaf extract treatment using cDNA microarrays. HIV-1 infection modulates the expression patterns of cellular genes involved in apoptosis, stress, cytokine, protein kinase C, and hedgehog signaling. HIV-1 infection up-regulates the expression of the heat-shock proteins hsp27 and hsp90, the DNA damage inducible transcript 1 gadd45, the p53-binding protein mdm2, and the hedgehog signal protein patched 1, while it down-regulates the expression of the anti-apoptotic BCL2-associated X protein Bax. Treatment with olive leaf extract reverses many of these HIV-1 infection-associated changes. Treatment of HIV-1-infected cells with olive leaf extract 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.

Blood pressure lowering effect of an olive leaf extract (Olea europaea) in L-NAME induced hypertension in rats.
Arzneimittelforschung. 2002;52(11):797-802.
Department of Pharmacology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
A specially prepared olive leaf extract has been tested for its blood pressure lowering activity in rats rendered hypertensive by daily oral doses of L-NAME (NG-nitro-L-arginine methyl ester, 50 mg/kg) for at least 4 weeks. Oral administration of the extract at different dose levels at the same time as L-NAME for a period of 8 weeks showed a dose dependent prophylactic effect against the rise in blood pressure induced by L-NAME, best effects being induced by a dose of 100 mg/kg of the extract. In rats previously rendered hypertensive by L-NAME for 6 weeks and then treated with that dose of the extract for a further 6 weeks without discontinuation of L-NAME, normalisation of the blood pressure was observed. The findings confirm previous reports on the hypotensive effects of olive leaf extract. The special extract, EFLA 943, was shown to give consistent results with little individual variability. The antihypertensive effect of the olive leaf extract may be related to a variety of factors involving reversal of vascular changes involved in the L-NAME induced hypertension.

Olive leaf extract has been tested in oral herpes.

Virgin Olive Oil Research
A mixture of compounds called phenols, extracted from virgin olive oil, inhibits the process by which colon cells become cancerous. Incubation of one cancer cell line with increasing concentrations of olive oil phenols for 24 hours protected the cells from DNA damage. Phenols extracted from virgin olive oil are capable of inhibiting several stages in colon carcinogenesis in vitro.

Olive Oil
Olive oil is becoming ever more popular in British kitchens, with more money spent on it than on all other types of cooking oils for the first time. Sales of olive oil have risen by almost 40 percent since 2000. Olive oil has overtaken other standard cooking oils. Extra virgin olive oil has verbascoside and other polyphenols.

Greek Olive Oil
With an annual production of 400,000 tonnes, Greece is the world's third largest producer of olive oil. Greece sells the bulk of its exports to Italian retailers, who treat and package the product under their own labels. Out of 100,000 tonnes of olive oil currently exported from Greece, only six percent are sold under Greek brands. But with the promise of a demand surge in the Far East and the United States now beckoning, Greek producers say they will no longer tolerate the dominance of foreign brands that essentially contain a Greek product. Twenty-five Greek olive oil brands are registered under the EU's Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) status, nine of them from the island of Crete.

Olive leaf extract product and pill emails
Q. Is it okay to take olive leaf extract supplement every day?
   A. It would be cautious, until we learn more about the long term benefit and side effect of olive leaf extract, to take a couple of days off a week and a week off each month.

Q. Hello from Greece. I am coming in touch with you on behalf of Alter Channel, a TV nationwide station. As far as I am aware you have a lot of knowledge on therapeutic use of olive extracts. There is a big discussion here in Greek media regarding the use of olive extracts for the prevention of cancer and there is a lot of speculation about this method and its validity. For this reason I kindly request you to give me your phone details so as to arrange a telephone discussion with you.

Q. Can I take olive leaf extract with L-lysine & Neem extract (Azadirachta Indica) Leaf or Seeds).? Or can I take olive leaf extract with Lemon Balm (Leaf extract). I want to know that how long you can take Olive leaf extract? Also can I take with Acyclovir medicine?
   A. Many herbs can be taken together if the dosage is very low of each, but each person is different and it is best to learn how each herb works by itself for a week or two before combining. The interactions of olive leaf extract supplement and medicines has not been studied.

Olive leaf extract has gotten great reviews on at least one other site, but one person says that it kills good bacteria as well as bad bacteria, so it must be taken with a probiotic. The same thing has been said in regards to oregano oil. So my question is this: if olive leaf extract and oregano oil really do kill the good bacteria, is it advisable to take them internally when you don’t seem to have any serious infections, even if you take probiotics to restore the good bacteria?
    There is no reason to take OLE or oregano oil products if there is no medical condition that is being treated. I have not seen studies that indicate these dietary supplements kill good bacteria in the gut in enough of a volume to cause harm. However, since probiotics are safe supplements and have many benefits, one could take them anyway on a regular basis.