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. The olives, leaves and olive pulp contain large amounts of hydroxytyrosol, most of which can be recovered to produce hydroxytyrosol extracts. However, it was found that black olives, such as common canned variety, containing iron gluconate contained little hydroxytyrosol, as iron salts are catalysts for its oxidation.
Hydroxytyrosol is mentioned by the scientific committee of the European Food Safety Authority as one of several olive oil polyphenols under preliminary research for the potential to affect blood lipid levels, although there is no evidence from high-quality clinical research to indicate that this effect exists.Animal research
As of 2015, the NOAEL for hydroxytyrosol in rats is 250 mg/kg/day, with a LOAEL of 500 mg/kg/day.
