Examining the Germ-Fighting Powers of Olive Leaf Extract and Thyme Oil

Jenn Hoskins
10th August, 2024

Examining the Germ-Fighting Powers of Olive Leaf Extract and Thyme Oil

Image Source: Natural Science News, 2024

Key Findings

  • The study by Al-Quds University tested olive leaf extracts, oleuropein, and thyme oil for antimicrobial activity against bacteria and fungi
  • Oleuropein showed complete antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, but was less effective against fungi
  • Combining oleuropein with thyme oil demonstrated strong synergistic antimicrobial effects, suggesting enhanced efficacy over individual agents
The search for natural antimicrobial and antioxidant agents has gained momentum due to the adverse effects associated with synthetic preservatives. A recent study by Al-Quds University aimed to evaluate the antimicrobial activity of two medicinal plant extracts and one active compound: olive leaf extracts, oleuropein, and thyme oil[1]. This study holds promise for addressing the increasing resistance of microorganisms to antibiotics and the demand for safer preservation methods. Olive leaf extract (OLE) has been traditionally used for its various health benefits, including antimicrobial properties[2]. Previous studies have demonstrated that OLE can inhibit the growth of major foodborne pathogens such as Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis at a concentration of 62.5 mg/ml[2]. Additionally, phenolic compounds from olive leaves have shown significant antimicrobial activities, highlighting the potential of olive leaves as a cost-effective source of natural antimicrobials[3]. However, the variability in phenolic content among different olive cultivars and their specific antimicrobial efficacy has been noted[4]. In the recent study, the researchers tested olive leaf extracts at concentrations of 0.2%, 0.3%, and 0.4% (w/v), oleuropein at 0.2%, 0.4%, and 0.6% (w/v), thyme oil at 0.1%, and a combination of oleuropein (0.4% w/v) and thyme oil (0.1% v/v) against three bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) and two fungal strains (Candida albicans and Aspergillus niger). The results showed that oleuropein exhibited complete antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, achieving a reduction of 7 logs during a 4-week storage period. However, oleuropein was less effective against fungal strains, with significant activity only at higher concentrations (0.6% w/v) against Aspergillus niger. The study also observed similar antibacterial and antifungal properties for olive leaf extracts, aligning with previous findings[2][3]. Notably, the combination of oleuropein and thyme oil demonstrated strong synergistic antimicrobial activity against the tested microorganisms. This synergy suggests that combining natural compounds can enhance their efficacy, potentially overcoming the limitations of individual agents. The findings from Al-Quds University expand on earlier research by providing a comprehensive evaluation of the antimicrobial properties of olive leaf extracts and oleuropein in combination with thyme oil. While previous studies focused on the antimicrobial potential of phenolic compounds isolated from olive leaves[3], this study highlights the practical application of these compounds in combination with other natural agents like thyme oil. This approach could pave the way for developing more effective and safer natural preservatives. Overall, the study underscores the potential of olive leaf extracts, oleuropein, and thyme oil as potent natural antimicrobial agents. These findings are particularly relevant in the context of rising antibiotic resistance and the need for safer alternatives to synthetic preservatives. By building on previous research and demonstrating the efficacy of these natural compounds, the study offers a promising solution for enhancing food safety and extending the shelf life of products without compromising human health.

MedicineBiochemPlant Science

References

Main Study

1) Evaluation of the antibacterial and antifungal properties of oleuropein, olea Europea leaf extract, and thymus vulgaris oil.

Published 9th August, 2024

https://doi.org/10.1186/s12906-024-04596-x

Related Studies

2) Assessment of the Antimicrobial Activity of Olive Leaf Extract Against Foodborne Bacterial Pathogens.

https://doi.org/10.3389/fmicb.2017.00113

3) Microbiological and Antioxidant Activity of Phenolic Compounds in Olive Leaf Extract.

https://doi.org/10.3390/molecules25245946

4) Antioxidant and Antimicrobial Activity of Hydroethanolic Leaf Extracts from Six Mediterranean Olive Cultivars.

https://doi.org/10.3390/antiox11091656


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