Olive Leaf

Common Names

How It Works
Olive leaf extract has not been shown to prevent or treat cancer in humans.
Olive leaves contain a substance called oleuropein, which is thought to help reduce cholesterol levels. Olive leaf extracts (OLE) also reduce glucose levels in the blood. Laboratory studies found that OLE can kill a number of microorganisms including yeasts, bacteria and fungi. It was also shown to have anticancer effects. Human studies are needed.
Purported Uses
- To prevent or treat cancer
  Laboratory results show possible benefit, but human studies have not been conducted.
- To lower cholesterol
  Animal studies have shown a possible effect. Human studies are lacking.
- To fight HIV
  Laboratory results show possible benefit, but human studies have not been conducted.
- To reduce high blood pressure
  Animal and human studies show that olive leaf extract can lower blood pressure.
- To fight infections
  Laboratory results show olive leaf extract to be effective against a variety of microorganisms.
- To promote urination
  There is no evidence to support this claim.
Do Not Take If
- You are taking blood pressure medicine: Olive leaf extract may increase the blood pressure lowering effect.
- You are taking insulin or other blood sugar medicine: Olive leaf extract may cause blood sugar levels to drop too low.
- You are undergoing chemotherapy: Olive leaf extract may interfere with the actions of certain chemotherapy drugs due to its antioxidant effects.
Side Effects
- The pollen from olive trees can cause severe respiratory allergy.
Scientific Name
Olea europaea
Clinical Summary
Derived from the olive plant, both leaves and the extract have been used to treat infections, inflammation, diabetes, and hypertension. A major component of olive leaf, oleuropein, has antioxidant properties ⁽¹⁾. Because of its hypoglycemic effects, the leaf extract can induce insulin release and improve peripheral uptake of glucose ⁽²⁾. Further, the leaf extracts demonstrated antimicrobial properties ⁽³⁾ ⁽²²⁾, anti-HIV ⁽⁴⁾, and anticancer ⁽¹³⁾ ⁽¹⁴⁾ ⁽¹⁵⁾ ⁽¹⁸⁾ ⁽¹⁹⁾ properties. Animal studies showed antiarrhythmic, spasmolytic, diuretic ⁽⁵⁾, antihypertensive ⁽⁶⁾, analgesic ⁽²⁰⁾ ⁽²¹⁾, and cholesterol-lowering ⁽⁷⁾ effects.
Small studies have shown effectiveness of olive leaf extract in reducing blood pressure in patients with hypertension ⁽¹⁶⁾ ⁽¹⁷⁾. The anticancer effects of olive leaf extract in humans are not known.
Purported Uses
- High cholesterol
- HIV and AIDS
- Hypertension
- Infections
- Promote urination
- Viral infections
Mechanism of Action
The cholesterol-lowering effects of olive leaf extracts (OLE) are thought to be due to oleuropein, a compound present in the leaves. Studies on hypercholesterolemic rats have shown that OLE is more effective at lowering cholesterol than pure oleuropein. This implies that a synergistic effect occurs between oleuropein and another substance within the leaf ⁽⁷⁾.
Oleuropein is converted into elenoic acid in the body which may prevent viruses and bacteria from replicating ⁽⁸⁾. The antihypertensive and vasodilating effects of olive leaf occurred independently of the integrity of the vascular endothelium ⁽⁹⁾. Constituents of olive leaf have been shown to strongly inhibit the complement system, although it is unknown what effect this has on the body ⁽¹⁰⁾.
Hypoglycemic activities of olive leaf are attributed to two mechanisms: potentiation of glucose-induced insulin release and increased peripheral uptake of glucose. Hypoglycemic activity is greater in samples collected in the winter months ⁽²⁾. OLE may prevent diabetic neuropathy by reducing glucose-induced apoptosis through the inhibition of neural caspase 3 activation ⁽²⁰⁾.
In vitro studies show that OLE has antimicrobial activities against E. coli, Pseudomonas aeruginosa, S. aureus, K. pneumoniae, Trichophyton mentagrophytes, Microsporum canis, T. rubrum and Candida albicans ⁽³⁾ ⁽²²⁾. Anti-HIV properties of OLE include up-regulation of the expression of apoptosis inhibitor proteins as well as protein kinase signaling molecules ⁽⁴⁾. OLE promotes cell differentiation ⁽¹⁸⁾and induces DNA fragmentation leading to apoptosis in leukemia cell line ⁽¹⁹⁾.
Adverse Reactions
- The pollen from olive tree can cause severe respiratory allergy ⁽¹²⁾.
Herb-Drug Interactions
Antihypertensive drugs: May increase blood pressure lowering effects ⁽⁶⁾.
Insulin and antidiabetic drugs: May increase hypoglycemic effects ⁽²⁾.
Chemotherapy drugs: May interfere with the actions of certain chemotherapy drugs due to its antioxidant effects.
References
1. Montilla MP, Agil A, Navarro MC, Jimenez MI, Garcia-Granados A, Parra A et al. Antioxidant activity of maslinic acid, a triterpene derivative obtained from Olea europaea. Planta Med 2003;69:472-4.
2. Gonzalez M, Zarzuelo A, Gamez MJ, Utrilla MP, Jimenez J, Osuna I. Hypoglycemic activity of olive leaf. Planta Med 1992;58:513-5.
3. Markin D, Duek L, Berdicevsky I. In vitro antimicrobial activity of olive leaves. Mycoses 2003;46:132-6.
4. Lee-Huang S, Zhang L, Huang PL, Chang YT, Huang PL. Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment. Biochem.Biophys.Res Commun. 2003;307:1029-37.
5. PDR for Herbal Medicines. Montvale, NJ: Medical Economics, 1998.
6. Somova LI, Shode FO, Ramnanan P, Nadar A. Antihypertensive, antiatherosclerotic and antioxidant activity of triterpenoids isolated from Olea europaea, subspecies africana leaves. Journal of Ethnopharmacology.Vol.84(2-3)()(pp 299-305), 2003. 2003;299-305.
7. Pasquale RD, Monforte A, Trozzi A, Raccuia S, Tommasini S, Ragusa S. Effects of leaves and shoot of Olea europaea L. and oleuropien on experimental hypercholesterolemia in rat. Plantes Med Phytother 1991;25:134-40.
8. Horn C. Olive leaf to fight infection. Natural Health 2000;30:40.
9. Zarzuelo A, Duarte J, Jimenez J, Gonzalez M, Utrilla MP. Vasodilator effect of olive leaf. Planta Med 1991;57:417-9.
10. Pieroni A, Heimler D, Pieters L, van Poel B, Vlietinck AJ. In vitro anti-complementary activity of flavonoids from olive (Olea europaea L.) leaves. Pharmazie 1996;51:765-8.
11. Brinker F. Herb Contraindications And Drug Interactions. Sandy, OR: Eclectic Medical Publications, 2001.
12. Liccardi G, D’Amato M, D’Amato G. Oleaceae pollinosis: a review. Int Arch.Allergy Immunol. 1996;111:210-7.
13. Kimura Y, Sumiyoshi M. Olive leaf extract and its main component oleuropein prevent chronic ultraviolet B radiation-induced skin damage and carcinogenesis in hairless mice. J Nutr. 2009 Nov;139(11):2079-86.
14. Anter J, Fernández-Bedmar Z, Villatoro-Pulido M, et al. A pilot study on the DNA-protective, cytotoxic, and apoptosis-inducing properties of olive-leaf extracts. Mutat Res. 2011 May 20. [Epub ahead of print].
15. Mijatovic SA, Timotijevic GS, Miljkovic DM, et al. Multiple antimelanoma potential of dry olive leaf extract. Int J Cancer. 2011 Apr 15;128(8):1955-65.
16. Perrinjaquet-Moccetti T, Busjahn A, Schmidlin C, et al. Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins. Phytother Res. 2008 Sep;22(9):1239-42.
17. Susalit E, Agus N, Effendi I, et al. Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril. Phytomedicine. 2011 Feb 15;18(4):251-8.
18. Abaza L, Talorete TP, Yamada P, et al. Induction of growth inhibition and differentiation of human leukemia HL-60 cells by a Tunisian gerboui olive leaf extract. Biosci Biotechnol Biochem. 2007 May;71(5):1306-12.
19. Anter J, Fernández-Bedmar Z, Villatoro-Pulido M, et a. A pilot study on the DNA-protective, cytotoxic, and apoptosis-inducing properties of olive-leaf extracts. Mutat Res. 2011 Aug 16;723(2):165-70.
20. Kaeidi A, Esmaeili-Mahani S, Sheibani V, et al. Olive (Olea europaea L.) leaf extract attenuates early diabetic neuropathic pain through prevention of high glucose-induced apoptosis: in vitro and in vivo studies. J Ethnopharmacol. 2011 Jun 14;136(1):188-96.
21. Esmaeili-Mahani S, Rezaeezadeh-Roukerd M, Esmaeilpour K, et al. Olive (Olea europaea L.) leaf extract elicits antinociceptive activity, potentiates morphine analgesia and suppresses morphine hyperalgesia in rats. J Ethnopharmacol. 2010 Oct 28;132(1):200-5.
22. Pereira AP, Ferreira IC, Marcelino F, et al. Phenolic compounds and antimicrobial activity of olive (Olea europaea L. Cv. Cobrançosa) leaves. Molecules. 2007 May 26;12(5):1153-62.