Olive leaf

Although olive oil extracted from the fruit of the tree is well known for its flavor and possible health benefits, the leaf and its extracts remain under preliminary research with unknown effects on human health.

[1][2] Chemical compounds in unprocessed olive leaf are oleuropein and hydroxytyrosol, as well as polyphenols and flavonoids, including luteolin, rutin, caffeic acid, catechin and apigenin.

[4] Oleuropein, together with other closely related compounds such as 10-hydroxyoleuropein, ligstroside and 10-hydroxyligstroside, are tyrosol esters of elenolic acid.

[2] The phenolic composition of olive leaf extract varies according to plant variety, harvesting season and method, leaf maturity, storage conditions and extraction method.

[5] Scientific evidence for the supposed health effect of using olive leaf extract to manage blood glucose levels has been deemed insufficient by the European Food Safety Authority to have any cause-and-effect relationship.