Olive leaf extract is an extraordinary and effective natural health remedy. Among its many therapeutic properties, it has a strong antiviral and immune system-boosting action, as proven by several scientific studies.
Recently, in response to growing consumer demand for supplements to boost natural defences, a number of leading pharmaceutical companies have developed supplements based on olive leaf extract.
Powerful natural antibiotic and antiviral
In 1854, Hanbury published an article in the Pharmaceutical Journal of Provincial Transactions reporting that a “decoction of olive leaves” had been found to be extremely effective in reducing fever due to a serious, and in many cases fatal, illness that had struck the island of Mytilene in 1843.
It was later reported that olive leaf extract was more effective in its antifever properties than quinine. Hanbury pointed out that similar observations had been made in France and Spain many years earlier (between 1811 and 1828).
It seems that, at the beginning of the 19th century, Spanish doctors sometimes prescribed olive leaves as a “febrifuge”, and as a consequence, during the Spanish War of 1808-1813, French officers of Sante often used them to treat cases of “intermittent fever”.
In 1906, the scientists claimed that olive leaf extracts were superior to quinine, at that time the main treatment for malaria. However, quinine was preferred because it was easier to administer.
Olive leaf infusion against the influenza virus
An Iranian study in 2006 was the first to investigate the effects of olive leaf extract on the influenza virus.
“Influenza viruses are the main etiological agents of human respiratory infections that inflict huge health and economic burdens. The results of the present study indicated that olive leaf extract has shown activity against the influenza virus. Furthermore, this antiviral effect could be due to inhibition of viral absorption or penetration.”
Antiviral action of oleuropein
Oleuropein is the main constituent of olive leaf infusion and is the compound that can regulate blood pressure. A study that summarises the benefits of oleuropein states:
“In addition to hypertension, oleuropein has been shown to have cardioprotective, anti-inflammatory, antioxidant, anti-cancer, anti-angiogenic and neuroprotective functions and therefore may have therapeutic potential for a variety of human diseases.”
In addition, it also acts as an antiviral by several mechanisms:  
- interfering with specific amino acid production processes vital to the virus life cycle;
- interfering with viral infection and/or proliferation by inactivating the virus or blocking its spread, replication or assembly on the cell membrane;
- activating the host immune defence through direct stimulation of phagocytosis;
- neutralising the production of reverse transcriptase and protease (i.e. the retroviral ability to alter host cell RNA);
- penetrating infected host cells and achieving an irreversible inhibition of viral replication.
Oleuropein has potent antiviral activities against several types of viruses, including major ones such as herpes mononucleosis, hepatitis virus, rotavirus, bovine rhinovirus, canine parvovirus, feline leukemia virus, viral hemorrhagic septicaemia virus (VHSV) and HIV.
Studies have also shown that oleuropein shows significant antiviral activity against respiratory syncytial virus and para-influenza virus type 3.
Based on Oleuropein’s recognised antiviral activity and numerous reports in AIDS patients using Oleuropein, the extract has been widely used to strengthen the immunity system, reduce viral load, alleviate chronic fatigue, aid in the treatment of Kaposi’s sarcoma, herpes simplex virus infections, and reduce the side effects of anti-retroviral drug therapy.
Azione antivirale dell’acido elenolico
Another active ingredient in olive leaf infusion is elenolic acid. In vitro, it has been shown to be a very powerful antibacterial and antiviral agent with a beneficial effect on the prevention and quick resolution of infectious diseases.
Some of the viruses that have shown susceptibility to elenolic acid in studies in vitro include: herpes (MRS); influenza A and B; Newcastle disease; parainfluenza 1, 2 and 3; coxsackie A21; enceflomyocarditis; polio 1, 2 and 3; vesicular stomatitis; sindbis; reovirus; Moloney’s murine leukemia; Rauscher’s murine leukemia; Moloney’s sarcoma.
Researchers have also shown that the elenolic acid salt, i. e. calcium elenolate, is another powerful antiviral effective in vitro in inhibiting the proliferation of several viruses, including: parainfluenza, herpes simplex, pseudorabies, polio viruses -1, -2, -3, rhinoviruses, myxoviruses, coxsackie viruses, varicella zoster, encephalomyocarditis viruses, and two strains of leukaemia viruses.      
Antiviral action of rutin
Rutin (also known as ‘vitamin P’) has a strong antioxidant action that helps prevent infectious diseases from the simplest (influenza) to the most important viral infections. It has a significant beneficial effect on microcirculation (protects against broken capillaries), makes the blood more fluid and inhibits the harmful effects of obesity, cholesterol and elevated glycemia.
It also acts on lymphatic circulation in the lower limbs, preventing fluid retention, and has an antihistamine effect.
Rutin is considered an antiviral agent for the treatment of infections caused by retroviruses, orthomyxoviruses, herpes viruses, hepatitis B viruses and hepatitis C viruses.
These are some of the several scientific studies which demonstrate the antiviral and immune-stimulating properties of Olive leaf extract. Dr. Adrian Hohenwarter MD. Botanical classification of olive leaf extract.
 Anni Schleicher. Antiviral effects of olive leaf extracts flagged amid heightened immunity tensions. NutritionInsight
 Sun, Wenyan et al. “Oleuropein, unexpected benefits!.” Oncotarget vol. 8,11 (2017): 17409.
 Paul S. Nash, DC, CCN, Lic. Acu. Herbal Health Report: Olive Leaf Extract Regains Interest as a Superb Anti-microbial Agent. Chiroweb
 Omar SH. Oleuropein in olive and its pharmacological effects. Sci Pharm. 2010;78(2):133-154.
 Ganeshpurkar A, Saluja AK. The Pharmacological Potential of Rutin. Saudi Pharm J. 2017;25(2):149-164.
 Pontoniere, Paolo. (2019). Olive Polyphenols and Malaria, a back-to-the-future Antiprotozoal strategy. 10.13140/RG.2.2.19830.65608.
 Elliot G. et al. Preliminary safety studies with calcium elenolate, an antiviral agent. Antimicrob. Agents and Chemother., 1969; 173-6.
 Soret M. Antiviral activity of calcium elenolate on parainfluenza infection of hamsters. Antimicrob. Agents and Chemother., 1969; 160-6.
 Renis H. In vitro antiviral activity of calcium elenolate. Antimicrob. Agents and Chemother., 1969; 167-72.
 Heinze J. et al. Specificity of the antiviral agent calcium elenolate. Antimicrob. Agents and Chemother. 1975: 8(4), 421-5.
 Renis H. Inactivation of DNA polymerases of Murine leukemia viruses by calcium elenolate. Nature New Biol. 1972; Aug. 30; 238(87):277-9.
 Renis H. Inactivation of myxoviruses by calcium elenolate. Antimicrob. Agents and Chemother., 1975, Aug. 8(2):194-9.
 Clewell AE, Béres E, Vértesi A, et al. A Comprehensive Toxicological Safety Assessment of an Extract of Olea Europaea L. Leaves (Bonolive™). Int J Toxicol. 2016;35(2):208-221.
 Guex CG, Reginato FZ, Figueredo KC, et al. Safety assessment of ethanolic extract of Olea europaea L. leaves after acute and subacute administration to Wistar rats. Regul Toxicol Pharmacol. 2018;95:395-399.
 Ali Akbar Nekooeian. The Antiinfluenza Virus Activity of Hydroalcoholic Extract of Olive Leaves. Volume 2, Issue 3 Summer 2006 Pages 163-168
 El, Sedef & Karakaya, Sibel. (2009). Olive tree (Olea europaea) leaves: Potential beneficial effects on human health. Nutrition reviews. 67. 632-8. 10.1111/j.1753-4887.2009.00248.x.
 How to Boost Your Immunity Naturally – P2: Olive leaf extract. BCNH