Along with oleocanthal and hydroxytyrosol, oleuropein is one of the main polyphenols found in extra virgin olive oil that determines its sensory characteristics and health benefits.
Oleuropein, one of the major phenolic compounds found in extra virgin olive oil, is key to many olive oil health benefits and even its flavor.
The olive tree produces the compound as a defensive mechanism, its bitterness acting as a natural deterrent to pests. That same bitterness translates to a marker of quality in oil.
Oleuropein, identified as the first secoiridoid in olive oil by Panizzi et al. in 1958, is a significant component of olive polyphenols. Its presence in olives and oil varies depending on the olive variety, milling techniques and technology and storage conditions.
Oleuropein serves as a quality marker throughout production. The bitter, pungent taste of extra virgin olive oil primarily arises from its main phenolic compounds, including oleocanthal, hydroxytyrosol and oleuropein.
Extensive research has explored the beneficial effects of oleuropein on ailments including cancer, hypertension, heart issues and various viral and bacterial diseases.
How oleuropein impacts sensory attributes.
Research conducted by Andrewes and colleagues in 2003 isolated and evaluated individual phenolic compounds present in olive oil.
They found that the compound p‑HPEA-EDA, a secoiridoid derivative of oleuropein, elicited a strong burning pungent sensation at the back of the throat, contributing significantly to the oil’s pungent attribute. In contrast, another compound, 3,4‑DHPEA-EDA, produced only a slight burning or numbing sensation, predominantly perceived on the tongue.
Further analysis using the calcium mobilization functional assay revealed that several phenolic compounds activate bitter taste receptors TAS2R1, TAS2R8 and TAS2R14.
Ligstroside aglycon and oleuropein aglycon were identified as the most potent bitter tastants in olive oil. TAS2R8 and TAS2R1 were found to be the primary bitter taste receptors responding to phenolic compounds, with oleuropein activating TAS2R8 exclusively, albeit with lower potency compared to the algycons.
While oleuropein has low potency towards the receptor TAS2R8, research suggests that the intensely bitter sensation experienced when chewing raw olives is primarily due to the spontaneous conversion of oleuropein into aglycon forms.
Oleuropein and oleuropein glucosidase are typically found in separate cellular compartments and only come into contact when olive fruit cells are damaged, such as during chewing or crushing for oil production.
Oleuropein’s role in olive oil health benefits
Oleuropein and its derivative, hydroxytyrosol, possess potent antioxidant properties, contributing to olive oil’s reputation for combating inflammation and associated diseases.
Notably, oleuropein has demonstrated a capacity to significantly reduce blood pressure, both systolic and diastolic, in animal models, aligning with olive leaf’s traditional use in treating hypertension.
Recent studies reveal that oleuropein’s mechanism in reducing blood pressure involves protecting the hypothalamus from oxidative stress through Nrf2-mediated signaling, offering potential as a preventive and therapeutic approach for hypertension.
Beyond blood pressure regulation, oleuropein exhibits various health-promoting functions, including cardioprotection, anti-inflammatory, antioxidant, anti-cancer, anti-angiogenic and neuroprotective effects. More