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Olive leaf

Plant Part Used


Active Constituents

Secoiridoids (including oleuropein,demethyloleuropein (30) and oleuroside); hydroxytyrosol (30);elenolic acid; phenolic glycosides (including caffeic acid); flavonoids (including hesperidin, rutin, apigenin, quercetin, kaempferol). (1) , (2) [span class=alert]

This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]


Olive trees, widely cultivated throughout Mediterranean countries as a source of olives and olive oil, have been traditionally used not only in foods, but in health conditions including malaria, infections, cardiovascular diseases, and for general well-being. (3) As early as 1855, medical reports have described the benefits of drinking a bitter tea brewed with leaves from the olive tree. Epidemiological data obtained from clinical studies have consistently demonstrated that the Mediterranean diet, rich in olive oil, fruits, vegetables, and grains is correlated with a lower than average risk of coronary heart disease. (4) The natural antioxidants, including oleuropein, from the olive tree may play a role in the prevention of cardiovascular diseases through a decreased formation of atherosclerotic plaques by inhibiting LDL oxidation. (5)

In the 1960s, a major pharmaceutical company studied the effects of elenolic acid as an antiviral agent in laboratory animals. The isolated calcium salt of elenolic acid was tested as a broad-spectrum antiviral agent active against all viruses tested. (6)

Interactions and Depletions


Dosage Info

Dosage Range

250-500mg (standardized extract), 1-3 times a day.

Tea: 3 to 4 cups, 2 teaspoonfuls of herb per cup throughout the day. (7)

Most Common Dosage

500mg (standardized extract), 3 times a day.

Tea: 3 cups, 2 teaspoonfuls of herb per cup throughout the day.


[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]

The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 4-23% oleuropein per dose (most products in the United States are 6-12% oleuropein).


Frequently Reported Uses

  • Antiviral. (HIV-1 inhibitors)
  • Chronic Fatigue Syndrome
  • Fibromyalgia
  • Ulcerative Colitis
  • Breast Cancer
Other Reported Uses
  • Antibacterial
  • Anticancer
  • Antifungal
  • Antimelanogenesis
  • Antiparasitic
  • Hypercholesterolemia
  • Hypertension
  • Anti-Inflammatory.
  • Antioxidant
  • Hypoglycemic
  • Immune Enhancement
  • Irritable Bowel Syndrome (IBS)

Toxicities & Precautions


Olive leaf is reported safe in recommended dosages.(8) It  has been  identified and documented as GRAS ( Generally Recognised As Safe) status by Europe and Middle East.(34)


Olive is categorized as an allergen.(32) Olive pollen may cause an allergic reaction, so olive products should be used with caution in sensitive individuals. (9)

Health Conditions

Based on pharmacology, use with caution in individuals with bleeding disorders.


Olive leaf extract has been reported to be an effective antimicrobial agent against a variety of pathogens, including Salmonella typhi, Vibrio parahaemolyticus, and Staphylococcus aureus (including penicillin-resistant strains); and Klebsiella pneumonia, and Escherichia coli, causal agents of intestinal or respiratory tract infections in humans. (10) The authors concluded that olive leaf could be considered a potentially effective antimicrobial agent for the treatment of intestinal or respiratory tract infections. The component usually associated with olive leaf’s antimicrobial properties is oleuropein. (11) , (12) Oleuropein has also been reported to directly stimulate macrophage activation in laboratory studies. (13)

Olive leaf extract has reported antiviral activity, reportedly caused by the constituent calcium elenolate, a derivative of elenolic acid. (14) , (15) Some viruses inhibited by calcium elenolate in vitro include rhinovirus, myxoviruses, Herpes simplex type I, Herpes simplex type II, Herpes zoster, Encephalomyocarditis, Polio 1, 2, and 3, two strains of leukemia virus, many strains of influenza and para-influenza viruses. (16) , (17) , (18) The mechanism of action of the antiviral activity is reported to include: (19)

  • An ability to interfere with critical amino acid production essential for viruses.
  • An ability to contain viral infection and/or spread by inactivating viruses or by preventing virus shedding, budding, or assembly at the cell membrane.
  • Ability to directly penetrate infected cells and stop viral replication.
  • In the case of retroviruses, it is able to neutralize the production of reverse transcriptase and protease.
  • Stimulation of phagocytosis.

As an antifungal and antiviral agent, olive leaf extract is currently used as a supportive agent in the management of chronic fatigue syndrome and fibromyalgia. Anecdotally, a European product containing 20% oleuropein has been reported effective in CFS and fibromyalgia.

An olive leaf extract was reported in a laboratory study to have vasodilating effects, seemingly independent of vascular endothelial integrity. (20) Traditional uses support olive leaf and olive oil in cardiovascular disease prevention. (21) , (22) Oleuropein, an antioxidant, has been reported to decrease the oxidation of LDL cholesterol. (23) Oxidized LDL is the most damaging form of cholesterol and can initiate damage to arterial tissues, thereby promoting atherosclerosis. Olive leaf has been reported to inhibit platelet aggregation and production of thromboxane A2 (a stimulator of platelet aggregation with vasodilatory effects). (24) Also of interest, is a recent study reporting that olive leaf extract inhibited both angiotensin converting enzymes. (25)

Studies in laboratory animals have reported hypoglycemic and hypolipidemic activity of olive leaf. (26) , (27) The active constituent was reported to be oleuropein, with a proposed mechanism of action of potentiation of glucose-induced insulin release, and an increase in peripheral blood glucose uptake.The oleuropein content also inhibits the alpha-glucosidase which will reduce the absorption of carbohydrates in the gut.(34)

As stated, olive leaf has antioxidant properties associated with oleuropein. There are reports that the antioxidant effect of olive leaf may be useful for hepatic-pancreatic cytoprotection.(34) Also, caffeic acid was reported to have antioxidant activity through the scavenging of superoxide anion. (28) Olive leaf has been reported to have anti-complement in vitro, and is a proposed mechanism for its anti-inflammatory effects. (29)

The hydroxytyrosol and oleuropein compound has been recognized to have anti-melanogenesis activity and some cytotoxic effects on cancer cells.(30)


  1. View Abstract: De Laurentis N, et al. Flavonoids from leaves of Olea europaea L. cultivars. Ann Pharm Fr. 1998;56(6):268-73.
  2. View Abstract: Ficarra P, et al. HPLC analysis of oleuropein and some flavonoids in leaf and bud of Olea europaea L. Farmaco. Jun1991;46(6):803-15.
  3. View Abstract: Ferro-Luzzi A, et al. Changing the Mediterranean diet: effects on blood lipids. Am J Clin Nutr. Nov1984;40(5):1027-37.
  4. View Abstract: Kushi LH, et al. Health implications of Mediterranean diets in light of contemporary knowledge. 2. Meat, wine, fats, and oils. Am J Clin Nutr. Jun1995;61(6 Suppl):1416S-1427S.
  5. View Abstract: Visoli F, et al. Oleuropein protects low density lipoprotein from oxidation. Life Sciences. 1994;55:1965-71.
  6. Soret MG. Antiviral activity of calcium elenolate on parainfluenza infection of hamsters. Antimicrobial Agents and Chemotherapy. 1969;9:160-66.
  7. PDR for Herbal Medicines, 2nd edition. Montvale, NJ: Medical Economics Company; 2000:557.
  8. PDR for Herbal Medicines, 2nd ed. Montvale, NJ: Medical Economics Company; 2000:557.
  9. View Abstract: Martinez A, et al. Identification of a 36-kDa olive-pollen allergen by in vitro and in vivo studies. Allergy. Jun1999;54(6):584-92.
  10. View Abstract: Bisignano G, et al. On the in-vitro antimicrobial activity of oleuropein and hydroxytyrosol. J Pharm Pharmacol. Aug1999;51(8):971-4.
  11. Petkov V, Manolov P. Pharmacological analysis of the iridoid oleuropein. Drug Res. 1972;22(9):1476-86.
  12. Juven B, et al. Studies on the mechanism of the antimicrobial action of oleuropein. J Appl Bact. 1972;35:559.
  13. View Abstract: Visioli F, et al. Oleuropein, the bitter principle of olives, enhances nitric oxide production by mouse macrophages. Life Sci. 1998;62(6):541-6.
  14. Renis HE. In vitro antiviral activity of calcium elenolate. Antimicrob. Agents Chemother. 1970;167-72.
  15. Heinze JE, et al. Specificity of the antiviral agent calcium elenolate. Antimicrob Agents Chemother. Oct1975;8(4):421-5.
  16. Renis HE. Inactivation of myxoviruses by calcium elenolate. Antimicrob Agents Chemother. Aug1975;8(2):194-9.
  17. Hirschman SZ. Inactivation of DNA polymerases of murine leukaemia viruses by calcium elenolate. Nat New Biol. Aug1972;238(87):277-9.
  18. Soret MG. Antiviral activity of calcium elenolate on parainfluenza infection of hamsters. Antimicrob Agents Chemother. 1969;9:160-6.
  19. Renis HE. In vitro antiviral activity of calcium elenolate. Antimicrob Agents Chemother. 1970;167-72.
  20. View Abstract: Zarzuelo A, et al. Vasodilator effect of olive leaf. Planta Med. Oct1991;57(5):417-9.
  21. View Abstract: Visioli F, et al. The effect of minor constituents of olive oil on cardiovascular disease: new findings. Nutr Rev. May1998;56(5 Pt 1):142-7.
  22. View Abstract: Giugliano D. Dietary antioxidants for cardiovascular prevention. Nutr Metab Cardiovasc Dis. Feb2000;10(1):38-44.
  23. View Abstract: Visioli F, et al. Oleuropein protects low density lipoprotein from oxidation. Life Sci. 1994;55(24):1965-71.
  24. View Abstract: Petroni A, et al. Inhibition of platelet aggregatiion and eicosanoid production by phenolic components of olive oil. Thromb Res. Apr1995;78(2)151-60.
  25. Hansen K, et al. Isolation of an angiotensin converting enzyme (ACE) inhibitor from olea europaea and olea lacea. Phytomedicine. 1996;2:319-325.
  26. View Abstract: Bennani-Kabchi N, et al. Effects of Olea europea var. oleaster leaves in hypercholesterolemic insulin-resistant sand rats. Therapie. Nov1999;54(6):717-23.
  27. View Abstract: Gonzalez M, et al. Hypoglycemic activity of olive leaf. Planta Medica. 1992;58:513-515.
  28. Chimi H, et al. Inhibition of iron toxicity in rat hepatocyte culture by natural phenolic compounds. Tox In Vitro. 1995;9:695-702.
  29. View Abstract: Pieroni A, et al. In vitro anti-complementary activity of flavonoids from olive (Olea europaea L.) leaves. Pharmazie. Oct1996;51(10):765-8.
  30. Han J, Talorete TP, Yamada P, Isoda H. Anti-proliferative and apoptotic effects of oleuropein and hydroxytyrosol on human breast cancer MCF-7 cells. Cytotechnology. Jan2009;59(1):45-53.
  31. Mazzio EA, Soliman KF. In vitro screening for the tumoricidal properties of international medicinal herbs. Phytother Res. Mar2009;23(3):385-398.
  32. Vigh-Conrad KA, Conrad DF, Preuss D. A protein allergen microarray detects specific IgE to pollen surface, cytoplasmic, and commercial allergen extracts. PLoS One. 16Apr2010;5(4):e10174.
  33. Lee-Huang S, Huang PL, Zhang D, Lee JW, Bao J, Sun Y, Chang YT, Zhang J, Huang PL. Discovery of small-molecule HIV-1 fusion and integrase inhibitors oleuropein and hydroxytyrosol: Part I. fusion [corrected] inhibition. Biochem Biophys Res Commun. 23Mar2007;354(4):872-878.
  34. Said. O, et al. Maintaining A Physiological Blood Glucose Level with ‘Glucolevel’ A Combination of Four Anti-Diabetes Plants Used in the Traditional Arab Herbal Medicine. eCAM 2008;5(4):421–428

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