Antiviral Effects of Olive Leaf

Olive Leaf extract has anti-viral, anti-bacterial and anti-fungal effects. Oleuropein and hydroxytyrosol are considered as main polyphenolic compounds in olive leaf. Oleuropein is converted into elenolic acid in the body which may prevent  bacteria and viruses  from replicating. Olive leaf extract has been shown to be effective against herpes, flu and colds, bacterial infections, vaginal yeast infections, malaria, and hepatitis. In 1969 scientists showed olive leaf constituents are strong in vitro inhibitors of numerous viruses, including parainfluenza, pseudorabies, herpes, and some forms of polio. Almost every virus tested, including several cold and influenza viruses, was inactivated when exposed to a constituent of olive leaf extracts (OLE), calcium elenolate. Olive leaf extract (Oleuropein) has been patented in the United States for antiviral activity against viral diseases, including hepatitis and herpes.

Antiviral and Antibacterial Activity

First researches by the pharmaceutical company Upjohn found extracts from olive leaves to be effective in treating infection caused by a large number of viruses as well as bacteria and parasitic protozoans. Oleuropein is able to stop viruses in their tracks, by neutralizing the enzymes that are important for the virus to replicate itself and spread. The major constituent of olive leaf is the phytochemical oleuropein, which is broken down to elenolic acid, has a potent anti-bacterial activity, and the ability to interfere with critical amino acid production essential for viruses. Investigators have showed olive leaf  constituents, especially elenolic acid and its salt, calcium elenolate, are effective in vitro against many viruses investigated, including parainfluenza, pseudorabies, Herpes simplex, Varicella zoster, coxsackie virus, myxoviruses, rhinoviruses, encephalomyocarditis, 2 strains of  leukemia virus and some forms of polio.

Olive leaf extract interacts with the protein in cold and flu virus particles to halt infection, according to a research reported in “Alternative Medicine Review“. In lab experiments, olive leaf extract has shown virucidal effect like herpes simplex 1 and 2 and herpes zoster. Research conducted in 1969, proved that a compound of oleuropein from the olive leaf could kill all viruses, including the herpes, against which it was investigated. In 1992 French scientists found that all of the herpes viruses were inhibited or killed by extracts from olive leaf.

Lab studies have a shown that olive leaf extracts can influence proteins that prevent cell death that may prove effective against the HIV (Human Immunodeficiency Virus).  Anti-HIV effects of  leaf extract include up-regulation of the expression of apoptosis inhibitor proteins as well as protein kinase signaling molecules. Cell-to-cell transmission of HIV was inhibited in a  dose-dependent manner with EC50s of 0.2 µg/ml, and HIV replication was inhibited in an in vitro experiment. The olive leaf extract indicates antiviral effect against viral haemorrhagic septicaemia rhabdovirus (VHSV). A study in reported 2003 edition of  Biochemical and Biophysical Research communications concluded that oleuropein helped the prevent the adherence of the hemorrhagic septicaemia virus to normal healthy cells, and reduce the infectivity of the virus by up to 30%.  Oleuropein, inhibited the in vitro infectivity of the viral haemorrhagic septicaemia virus. Incubation of virus with oleuropein before infection reduced the viral infectivity to 10 and 30%, respectively.

Olive leaf extracts has been found to kill a number of microorganisms including, yeasts, bacteria and fungi. Olive leaf extract (oleuropein) has been shown to have strong antimicrobial effect against both Gram Negative and Gram-positive bacteria as well as mycoplasma. Research reported by the “American Society for Microbiology“, found that OLE (olive leaf extract) inhibited the growth of every virus, bacteria, fungi and protozoa it was tested against.

An aqueous extract of olive leaf was bactericidal against Klebsiella pneumoniae, Pseudomonas aeruginosa, E. coli, and Staphylococcus aureus. Researches in Israel found the extract efficacious against Streptococcus by damaging the cell membrane of the bacteria, and therefore allowing intercellular substances like potassium, phosphorus and glutamate toleak out, disabling the bacteria. A study reported in the Apr 2003 edition of  “Mycoses” explored the effects of olive leaf extract against strains of various bacteria and fungi in vitro. Within 3 hours, olive leaf extracts killed nearly all bacteria, and within 24 hours, it completely destroyed candida, the yeast-like fungus responsible for vaginal yeast infections. New researches demonstrated the antimicrobial activity of olive leaf extracts against Campylobacter jejuni, H. pylori and MRSA (methicillin-resistant Staphylococcus aureus). According to a study reported in in May 2009  in the International Journal of Antimicrobial Agents OLE (olive leaf extract) may reduce levels of the bacteria H. pylori and Campylobacter jejuni in the digestive tract.

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