Olive phenolics in general, which are present in high levels in olive leaf supplements, appears to potently protect LDL cholesterol from oxidation; this is attributed to the anti-inflammatory effects of hydroxytyrosol, and appears to be active at a low enough dose to apply to consumption of olive product consumption. Olive leaf may also benficially influence the levels of lipoproteins in a beneficial manner (LDL, HDL, total cholesterol) although the actual changes in lipoprotein content is rather small. Overall, olive phenolics are more anti-artherosclerotic than they are cholesterol reducing.
Oleuropein is a chemical compound found in olive leaf from the olive tree (and leaves of privet) 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. Oleuropein preparations have been claimed to strengthen the immune system power acts as a free radical scavenger, can boost body immunity & enhance functions of human body.