Extra Virgin Olive Oil Poyphenols: Hydroxytyrosol

Posted by

Exploring the extraordinary benefits of olive oil polyphenols

Updated November 26th 2021

Polyphenols And Hydroxytyrosol
Polyphenols And Hydroxytyrosol


Polyphenol Hydroxytyrosol

Hydroxytyrosol is a powerful polyphenol which occurs naturally in the olive fruit, pulp, leaves and mill waste waters. Chemically, hydroxytyrosol is described as 4-(2-hydroxyethyl)-1,2-benzendiol, with the chemical formula C8H10O3.2 

Hydroxytyrosol is a well-known minor component found in extra virgin olive oil, which is derived from hydrolysis of the polyphenol oleuropein during olive maturation and olive oil storage. The compound plays an important role in the complex and varied flavour of olives and extra virgin olive oil.

It is also a vital component which largely adds to the stability and longevity of extra virgin olive oil. 

Hydroxytyrosol is hydrophilic, and absorbed in a dose-dependent manner in humans, with absorption occurring in the small intestine and colon. Uniquely, hydroxytyrosol is the only polyphenol which is able to cross the blood brain barrier, which allows it to have a significant action to scavenge free radicals in the nervous system.

Health Benefits Of Hydroxytyrosol In Extra Virgin Olive Oil

Hydroxytyrosol has a potent antioxidant activity. It has one of the highest know ORAC (oxygen radical absorbance capacity) results known for a natural antioxidant. ORAC is a method used to determine the antioxidant capacity of a food or chemical substance.

There is also evidence related to the health benefits of hydroxytyrosol in extra virgin olive oil in the following areas:

Anticancer Activity

Hydroxytyrosol in extra virgin olive oil has the capacity to inhibit proliferation and promote apoptosis of several tumour cells.Therefore, it has been suggested that hydroxytyrosol may have anticancer effects. The exact mechanism of these effects is not well defined, and research continues in this space.

Anti-inflammatory Activity 

Research has shown that hydroxytyrosol in extra virgin olive oil can reduce the production of cytokine tumor necrosis factor alpha (TNF alpha) in animal models of inflammation.Animal based research has also shown that hydroxytyrosol in extra virgin olive oil may be able to reduce acute inflammation and associated pain.

Antimicrobial Activity 

In vitro experiments have shown that hydroxytyrosol in extra virgin olive oil has antimicrobial properties against infectious respiratory and gastrointestinal pathogens.It is also known that hydroxytyrosol in extra virgin olive oil has activity against gram positive and gram-negative bacteria. In general, polyphenols have been reported to have wide antimicrobial activity, such as antibacterial, antiviral and antifungal effects.

Antithrombotic Activity 

A human study showed that hydroxytyrosol in extra virgin olive oil was able to lower serum thromboxane B2 levels, leading to an anti-aggregatory platelet effect.Other research supports this finding, showing that hydroxytyrosol significantly reduces platelet aggregation.

Antiatherogenic Capacity And Cardioprotective Effect 

Numerous studies have demonstrated the importance of naturally occurring dietary polyphenols in promoting cardiovascular health. Within the Mediterranean diet much research has focused on active phenolic compounds present in virgin olive oils to aid in explaining reduced mortality and morbidity observed. Among them, two isolated compounds, oleuropein and hydroxytyrosol, have received special attention. These compounds show several anti-inflammatory and anti-atherogenic activities, such as the inhibition of LDL oxidation, platelet aggregation, and other factors involved in the development of atherosclerosis.

It is known that hydroxytyrosol in extra virgin olive oil is a powerful scavenger of free radicals which allows for the reduction in oxidation of low-density-lipoproteins (LDL), potentially reducing the risk of atherosclerosis.

The importance of hydroxytyrosol in protection of low-density lipoproteins and consequently its implication in the reduction of cardiovascular disease risk has been highlighted by the European Food Safety Authority, concluding that 5 mg of hydroxytyrosol and its derivatives should be consumed daily to reach this effect at physiological level.

Effects on Endothelial Dysfunction

Reactive oxygen species (ROS) are critically involved in the endothelial dysfunction that contributes to atherosclerosis development. Oxidative stress-induced endothelial dysfunction probably represents one of the first stages in the development of atherosclerotic lesions. Accordingly, the atherosclerotic vessel wall contains increased levels of ROS, which affect several redox–sensitive pathways in vascular cells, resulting in a markedly altered cellular composition of the tissue. Migration and proliferation of vascular smooth muscle cells in the area is induced, as well as expression of adhesion molecules and chemotactic factors by the endothelium. Consequently, increased arterial adhesiveness at predisposed sites provides an excellent environment for local infiltration of circulating immune cells, resulting in chronic inflammation. Thus, direct reduction of levels of ROS and/or stimulation of anti-oxidant defenses at these levels could avoid atherosclerosis development.

Retino-Protective Activity 

Hydroxytyrosol in extra virgin olive oil may play a role in reducing the risk of age-related macular degeneration, however further research is required in this area to determine the exact mechanism and importance of this preliminary research finding.

Skin Related Effects 

It is believed that oxidative stress plays a major role in UVA-induced protein damage to the skin. Preliminary research shows that hydroxytyrosol in extra virgin olive oil can work to prevent such UVA damage in melanoma cells.

Polyphenols : The Magic Ingredient In Extra Virgin Olive Oil

The consumption of extra virgin olive oil is a key feature of the Mediterranean Diet, which has been largely associated to several health benefits. It is now well established that these beneficial effects are due to the polyphenol content of extra virgin olive oil which are known for their remarkable antioxidant activity.

There are more than 30 phenolic compounds that have been identified in extra virgin olive oil, but not all of them are present in every oil. The large variety of polyphenols found in extra virgin olive oil is different in chemical structures and concentrations depending on several factors including: olive variety, region in which the olive is grown, agricultural techniques, maturity of the olive fruit at harvest, and processing. Indeed, different varieties, cultivated in the same environment and processed at a fixed ripening stage, produce extra virgin olive oil with different total polyphenol profiles.

This continues our series of articles about the polyphenol content of our new harvest extra virgin olive oil and what they can do to improve our health. As we have reported, this year’s harvest has produced a low acidity level of 0.2% together with the highest level of polyphenols yet seen in our extra virgin olive oil of 644 mg/kg