“ In light of the unique combination properties of oleuropein it looks like we should go back to the future, and continue to exploit this key dietary component of the Mediterranean Diet to promote human health.1 ”
Olive leaf extract is a supplement that is derived from the olive leaf, which contains bioactive compounds that provide a health and wellness tonic that has many researched health benefits. The extract contains a wide variety of compounds which work synergistically to deliver a multitude of therapeutic actions.2, 3
Production of Olive Leaf Extract
Research Related to Olive Leaf Extract
The unique combination of biophenols in the olive leaf have many potential health benefits.
The below table summarises some of the major research in this area, which largely pertains to the two major biophenols found in the olive leaf – oleuropein and hydroxytyrosol.
It must be noted that overall, when compared with Extra Virgin Olive Oil, there is limited research related to the health attributes of olive leaf extract. There is also an absence of systematic literature reviews – this is a great opportunity for researchers to explore. The evidence contained in the below table is a summary of what is available at present, with respect to the pharmacotherapeutic benefits of olive leaf extract.
- Natural antioxidant 4, 5
- Some evidence to show high antioxidant activity against lipid peroxidation 5
- In vitro and animal studies show that olive leaf extract has some potential activity against the influenza virus 6
- Research suggests that olive leaf extract may reduce the infectivity and inhibit the replication of viruses that cause colds, influenza and lower respiratory tract infections – further clinical trials in humans are needed to validate these findings 6
- Olive leaf extract has been shown to stimulate phagocytosis – which may enhance the body’s response to a viral infection 6
- Gargling olive leaf tea may alleviate symptoms of a sore throat – potentially due to a reduction of inflammation and viral infectivity 6
- Improved insulin sensitivity has been demonstrated in human research 7
- Various anti-cancer effects reported in the evidence – such as in breast cancer, colorectal cancer, chronic leukemia and prostate cancer 8-11
- Reported ability to stop the angiogenic process in cancer, which triggers tumor growth (oleuropein is a potent antioxidant and anti-angiogenic compound) 1
- In vitro research shows that the phytochemicals in olive leaf extract inhibited cancer and endothelial cell proliferation 12
- Further clinical trials in humans are needed to validate these findings
- Evidence of hypotensive and lipid lowering effects in human research 13, 14,15
- Evidence of improved vascular function in human research 16
- Animal research shows potential critical effects on bone formation and maintenance – could be useful in the treatment of osteoporosis symptoms 17
- Possible antimicrobial effects in the gastrointestinal tract 18
- Evidence shows general antibacterial and antifungal activity 19
- Potential reduction of skin erythema (redness) 20
- Potential improvement in skin blood flow and dehydration 20
- In vitro activity to protect against skin cancer (inhibiting cell reproduction and inducing early apoptosis) 21
- Possible benefits for arthritis – in vivo animal research shows a reduction in swelling 22
- Helps decrease the production of cytokines and enzymes that are markers for inflammatory processes in diseases such as arthritis 1
- Olive biophenols have been shown in vitro to serve as agents to prevent neurodegenerative diseases such as Alzheimer’s Disease (e.g. diseases caused by oxidative stress) 23
Traditional natural medicine references associate olive leaf extract with many other medicinal properties, such as: 24, 25
Note: there are many more references available to support the health benefits of olive leaf extract. Our regular blog posts, and newsletters will contain these details. Subscribe here to receive our regular newsletter, and stay up-to-date on the benefits of olive leaf extract for health.
Safety and Tolerability
Regulatory bodies across the globe have published olive leaf extract monographs that discuss safety and tolerability of the product. Details of these monographs are summarized below.26-28
Suggested duration of use:
For general use: Traditionally, olive leaf extract was used over a period of 2 – 4 weeks.
For use as a diuretic: Occasional use is recommended, as required for symptom relief.
It is always important to note, that if symptoms persist for longer than one week during the use of the product, a qualified healthcare professional should be consulted.
General safety and toxicity information:
In-market use of olive leaf extract, over many years, has demonstrated that the product is well tolerated by most patients.
There is limited toxicology data for olive leaf extract in humans. One study showed that use of an olive leaf extract over a 15 day to 12-week period demonstrated good tolerability. In addition, a study in 188 patients treated with olive leaf extract reported no serious adverse effects. There is also some evidence of the product being well tolerated in animal species.
Possible side effects:
No serious adverse effects have been reported in clinical studies involving olive leaf extract.
Allergic reactions are possible in people who have an allergy to plants of the Oleaceae family.
Some reports of rhinitis or bronchial asthma have been reported (frequency is unknown).
Other possible adverse effects that have been experienced in small numbers of people include:
- Erythema multiforme
- Rash or hives
- Nausea and/or vomiting
- Abdominal pain
- Pharyngeal oedema
- Depressed consciousness
- Vulvovaginal candidiasis
In cases where olive leaf extract is indicated for chronic use there may be an adverse reaction experienced – the Herxheimer (or “die-off”) effect. This is a process whereby the body starts to eliminate toxins which may result in symptoms such as headaches, swelling in the mouth/throat, rashes, fatigue, diarrhoea, joint aches and flu-like symptoms.29
- Hypertensive agents – possible potentiating affect – consult a healthcare practitioner prior to use.
- Hypoglycemic agents – possible additive effect – consult a healthcare practitioner prior to use.
Contraindications and Precautions:
- Hypersensitivity to olive leaf extract and to other plants of the Oleaceae family
- Safety during pregnancy and breastfeeding has not been established
- In cases of a kidney disorder / taking diuretics consult a healthcare professional prior to use
- Barbara B, Toietta G, Maggio R, et al. Effects of olive-derived oleuropein on human health. Int J Mol Sci. 2014;15(10):18508–24.
- Vogel P, Machado I, Garavaglia J, et al. Polyphenol benefits of olive leaf (Olea europaea L.) to human health. Nutr Hosp. 2015;31(3):1427–33.
- Ali Hashmi M, Hanif M, Farooq U, et al. Traditional uses, phytochemistry and pharmacology of Olea europaea (Olive). Ev Based Complement Alternat Med. 2015; doi:10.1155/2015/541591.
- Lee O, Lee B. Antioxidant and antimicrobial activities of individual and combined phenolics in Olea europaea leaf extract. Bioresor Technol. 2010; 101:3751-4.
- Umeno A, Takashima M, Murotomi K, et al. Radical-scavenging Activity and Antioxidative Effects of Olive Leaf Components Oleuropein and Hydroxytyrosol in Comparison with Homovanillic Alcohol. J Ole Sci. 2015; 64:7;793-800
- Roxas M. Jurenka J. Colds and Influenza: A review of diagnosis and conventional, botanical and nutritional considerations. Alt Med Rev. 2007.2(1):25-48.
- de Bock M, Daerraik J, Brennan C, et al. Olive ( O l e a e u r o p a e a L.) Leaf Biophenols Improve Insulin Sensitivity in Middle-Aged Overweight Men: A Randomized, Placebo-Controlled, Crossover Trial. 2013; 8(3):1-8.
- Boss A, Bishop S, Marlow G, et al. Evidence to Support the Anti-Cancer Effect of Olive Leaf Extract and Future Directions. Nutrients. 2016;8:513.
- Milanese S, Bigdeli M, Rasoulian B, et al. The effect of olive leaf extract on antioxidant enzymes activity and tumor growth in breast cancer. Thrita. 2014;3(1): doi: 10.5812/thrita.12914
- Cardeno A, Sanchez-Hidalgo M, Rossillo M, et al. Oleuropein, a Secoiridoid Derived from Olive Tree, Inhibits the Proliferation of Human Colorectal Cancer Cell Through Downregulation of HIF-1α. Nutr Cancer. 2013;65(1):147–56.
- Samet I, Han J, Jlaiel L, et al. Olive (Olea europaea) Leaf Extract Induces Apoptosis and Monocyte/Macrophage Differentiation in Human Chronic Myelogenous Leukemia K562 Cells: Insight into the Underlying Mechanism. Oxid Med Cell Longev. 2014; :927619. doi: 10.1155/2014/927619.
- Goulas V, Exarchou V, Troganis A, et al. Phytochemicals in olive-leaf extracts and their antiproliferative activity against cancer and endothelial cells. Mol Nutr Food Res. 2009;53(5):600–8.
- Lockyer S, Rowland I, Spencer J, et al. Impact of phenolic‑rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trial. Eur J Nutr. 2017; 56(4):1421-1432.
- Perrinjaquet-Moccetti T, 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.
- Susalit E, Agus N, Tjandrawinata R, 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.
- Lockyer S, Corona G, Yaqoob P, et al. Secoiridoids delivered as olive leaf extract induce acute improvements in human vascular function and reduction of an inflammatory cytokine: a randomised, doubleblind, placebo-controlled, cross-over trial. Br J Nutr. 2015 Jul 14;114(1):75-83.
- Hagiwara K, Goto T, Araki M, et al. Olive polyphenol hydroxytyrosol prevents bone loss. Eur J Pharmacol. 2011;662:78–84.
- Sudjana A, D’Orazio C, Ryan V, et al. Antimicrobial activity of commercial Olea europaea (olive) leaf extract. Int J Antimicrob Agents. 2009;33:461–3.
- Pereira A, Ferreira I, Marcelino F, et al. Phenolic Compounds and Antimicrobial Activity of Olive (Olea europaea L. Cv. Cobrançosa) Leaves. Molecules. 2007;12:1153–62.
- Perugini P, Vettor M, Rona C, et al. Efficacy of oleuropein against UVB irradiation: preliminary evaluation. In J Cosmet Sci. 2008. 30: 113–120. doi:10.1111/j.1468-2494.2008.00424.x
- Mijatovic S, Timotijevic G, Miljkovic J. Multiple antimelanoma potential of dry olive leaf extract. Int J Cancer. 2011;128(8):1955–65.
- Gong D, Geng C, Jiang L, et al. Mechanisms of olive leaf extract-ameliorated rat arthritis caused by kaolin and carrageenan. Phytother Res. 2012;26(3):397–402.
- Omar S, Kerr P, Scott C, et al. Olive (Olea europaea L.) biophenols: a nutraceutical against oxidative stress in SH-SY5Y cells. Molecules. 2017;22:1858–78.
- Grieve M. A Modern Herbal. Volume 2. 1971. Harcourt, Bryce and Company: New York.
- Hakim G, Chishti N. The traditional healer’s handbook: a classic guide to the medicine of Avicenna. 1998. Healing Arts Press: Vermont.
- EMA 2012a. European Medicines Agency. Community herbal monograph on Olea europaea L folium. (EMA/HMPC/43057/2009)
- EMA 2012b. European Medicines Agency. Assessment on Olea europaea L folium. (EMA/HMPC/43056/2009)
- Health Canada monograph. Olive Leaf – Olea europaea. 8 December 2015.
- Ritchason J. Olive Leaf Extract – potent antibacterial, antiviral and antifungal agent. 1999. Woodland Publishing: Utah.