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The olive – antimicrobial compounds

The olive – antimicrobial compounds

The olive tree provides us with a multitude of elements (olive fruit, olive seed, olive leaf) which can naturally protect the body from microbial pathogens. In ancient times, olive oil and olive leaf extract have been used in traditional medicine as an antimicrobial ingredient, when consumed and/or when applied to the skin for infection. Here, we explore the science behind this aspect of the olive, to ascertain the strength behind the use of the olive to fight infection.


Olive Oil as an Antimicrobial

There is evidence to support the fact that olive oils with a high polyphenol content (e.g. Extra Virgin Olive Oil) can inhibit the growth of pathogenic bacteria.1 Specifically, the antimicrobial activity of olive oil has been attributed to polyphenols oleuropein, hydroxytyrosol ad tyrosol. Additionally, particular polyphenols contained in olive oil, oleuropein and ligstroside aglycons have been shown to have strong bactericidal activity against Helicobacter pylori.1

There is an abundance of in vitro evidence that demonstrates the antimicrobial activity of olive oil, with findings showing:1

  • Higher activity against gram positive bacteria, than gram negative organisms
  • Bactericidal activity against enteric microorganisms such as Escherichia coli and Clostridium perfringens.
  • Bactericidal affect against cariogenic bacteria Streptococcus mutants.
  • Strong bactericidal activity against food borne pathogens (possible role as a protective ingredient in food products).

Human research relating to pressure ulcers in immobilized patients showed promising results for the topic use of olive oil.2


Olive Leaf as an Antimicrobial

Dating back to 1969, researchers discovered that olive leaf extract was a powerful in vitro inhibitor of viruses, including parainfluenza, herpes, pseudorabies and some types of polio.3 More recent research also showed that olive leaf extract has activity against:

  • the Human Immunodeficiency Virus (HIV) in terms of inhibiting viral replication, through neutralizing reverse transcriptase and protease.3
  • the Human Immunodeficiency Virus (HIV) in terms of inhibiting viral replication, through neutralizing reverse transcriptase and protease.3
  • yeasts, molds, fungi, mycoplasmas and other parasites.4

Olive leaf has also been shown to inhibit the growth of gram negative and positive bacteria, yeasts and parasites.3 Specifically, there is in vitro research to show activity against Helicobacter pylori and Campylobacter jejuni, which shows the potential of the extract to regulate the composition of the gastric flora, through selectively reducing these bacteria levels.5 In addition, research has shown that olive leaf extract has an anti-fungal action in vitro, specifically against the following organisms – Saccharomyces cerevisiae, Schizosaccharomyces pombe, Saccharomyces uvarum, Candida oleophila, Metschnikowia fructicola and Kloeckera apiculata.6

View article references

  1. Brenes M, Medina E, Romero C, et al. Antimicrobial activity of olive oil. Agro Food Industry Hi Tech.2007;18(4):6–8.
  2. Perez-Lupianez I, Uttumchandani S, Morilla-Herrera J, et al. Topical olive oil is not inferior to hyperoxygenated fatty aids to prevent pressure ulcers in high-risk immobilised patients in home care. Results of a multicentre randomised triple-blind controlled non-inferiority trial. PLoS One. 2015;10(4): doi: 10.1371/journal.pone.0122238.
  3. Olive Leaf Monograph. Alternative Medicine Review. 2009(1):62–6.
  4. Nasrollahi Z, Abolhasannezhad M. Evaluation of the antifungal activity of olive leaf aqueous extracts against Candida albicans PTCC-5027. Curr Med Mycol. 2015;1(4):37–9.
  5. 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.
  6. Korukluoglu M, Sahan Y, Yigit A, et al. Antifungal activity of olive leaf (Olea Europaea) extracts from the Trilye Region of Turkey. Annals of Microbiology. 2006;56:359.