Oleuropein 【Sources and habitation】 Oleuropein is a chemical compound found in olive leaf from the olive tree together with other closely related compounds such as 10-hydroxyoleuropein, ligstroside, and 10-hydroxyligstroside. All these compounds are tyrosol esters of elenolic acid that are further hydroxylated and glycosylated. Oleuropein and its metabolite hydroxytyrosol have powerful antioxidant activity both in vivo and in vitro and give extra-virgin olive oil its bitter, pungent taste. 【Molecular formula】C25H32O13 【Mol. mass】540.514 【CAS number】32619-42-4 【Constitutional Formula】 【Indication and use】 Oleuropein has been the subject of extensive in vitro (test tube) and animal studies, which have demonstrated protective and antioxidant activity, especially prevention of the oxidation of LDL cholesterol. Animal studies suggest oleuropein may help maintain healthy blood sugar levels, while animal and laboratory studies also suggest that calcium elenolate, one of olive's active components, may support the body's defense system. In vitro studies of elenolic acid, the hydrolyzed form of oleuropein, have shown it to have potential protective benefits.