Hydroxytyrosol

Hydroxytyrosol is a phenylethanoid, a type of phenolic phytochemical with antioxidant properties in vitro. In nature, hydroxytyrosol is found in olive leaf and olive oil, in the form of its elenolic acid ester oleuropein and, especially after degradation, in its plain form.
Hydroxytyrosol itself in pure form is a colorless, odorless liquid. But in addition to its pure form, it is more commonly available as a beige colored powder, which is a natural byproduct of the waste water of the olive oil industry. In addition to these natural forms, hydroxytyrosol can also be produced synthetically as either a pure white powder or as a clear liquid, using patented manufacturing techniques. Both the natural and synthetic forms are used in food stuffs and the cosmetics industry. The olives, leaves and olive pulp contain large amounts of hydroxytyrosol (compared to olive oil), most of which can be recovered to produce hydroxytyrosol extracts. However, it was found that black olives, such as common canned variety, containing iron(II) gluconate contained little hydroxytyrosol, as iron salts are catalysts for its oxidation.
The European Food Safety Authority (EFSA) has issued a scientific opinion on health claims in relation to dietary consumption of hydroxytyrosol and related polyphenol compounds from olive fruit and oil and protection of blood lipids from oxidative damage. Oxidative damage is known to adversely affect cardiovascular health (EFSA Journal 2011;9(4):2033).
On the basis of the data presented, the EFSA concluded that a cause-and-effect relationship has been established between the consumption of hydroxytyrosol and related compounds from olives and olive oil and protection of blood lipids from oxidative damage. To this extent there is an approved health claim relating to the consumption of olive oil polyphenols containing at least 5mg of hydroxytyrosol and its derivatives (e.g. oleuropein complex and tyrosol) per 20g of olive oil.
Mediterranean diet.
Mediterranean diets, characterised by regular intake of olive oil, have been shown to have health benefits, including reduced rates of heart attack and stroke. As a result, there is a considerable amount of research trying to understand which aspects of the diet may lead to these benefits. Most of the focus has been on extra virgin olive oil and its components, notably the phenols hydroxytyrosol and oleuropein. The research suggests that hydroxytyrosol may have beneficial effects on healthy individuals in preventing oxidation of LDL cholesterol, leading to atherosclerosis, which can increase the risk of heart attack and stroke.
Chemical reaction.
In nature, hydroxytyrosol is generated by the hydrolysis of oleuropein that occurs during olive ripening. Oleuropein is accumulated in olive leaf and fruit as a defense mechanism against pathogens and herbivores. During olive ripening or when the olive tissue is damaged by pathogens, herbivores, or mechanical damage, the enzyme β-glucosidase helps generate hydroxytyrosol via hydrolysis from oleuropein.