Properties and uses of Olea europaea
Keywords:Olea europaea, oleuropein, hydroxytyrosol, polyphenols, cardiometabolic prevention, antioxidant action
AbstractThe olive tree (Olea europaea L.) is rich in polyphenols and has been used since ancient times as a source of food. Olives, its fruits, are used for the extraction of olive oil and, to a lesser extent, for direct use as food. In addition, the olive pomace, a byproduct of the olive oil extraction process made up of husks, pulp residue and pits, is an interesting source of phenolic compounds, in particular oleuropein and ligstroside derivatives, flavonoids, phenolic acids and lignans. Olive oil is mainly composed of triacylglycerols (TAG; 98–99%), predominantly with monounsaturated oleic acid (up to 83%) with the remainder being palmitic, linoleic, stearic and palmitoleic acid. There are also several lipophilic or amphiphilic microconstituents in virgin olive oil, including phytosterols, squalene, tocopherols, phenolic compounds and terpenic acid derivatives. Phenolic compounds, in turn, are present as phenolic acids or alcohols, oleuropein derivatives, lignans and flavonoids. There are many applications of the olive tree in clinical practice and several trials have demonstrated its associated beneficial properties. Polyphenols are mainly characterized by an antioxidant action; among these, hydroxytyrosol (HT), which derives from the acid hydrolysis of oleuropein, has the greater antioxidant power. In addition, these compounds can prevent cells from initiating neoplastic transformation. They also seem to be helpful in preventing cardiometabolic derangements, in improvement of the inflammatory response and modulation of bone metabolism.