Olive trees can live more than thousand years thanks to a compound called oleuropein.
Oleuropein is a polyphenolic compound found abundantly in olive oil and leaves of the olive tree. Oleuropein and its metabolite, hydroxytyrosol, have powerful antioxidant activities, which might be responsible for olive oil's anti-inflammatory, antioxidant, and disease-fighting properties.

Studies suggest that oleuropein is a very effective tool to both prevent and treat high blood pressure. Beyond hypertension, oleuropein has been shown to have cardioprotective, anti-inflammatory, antioxidant, anti-cancer, anti-angiogenic and neuroprotective functions. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5392257/)
Fun fact: Average life expectancy in Crete is 82 years which is a lot compared to its peers. One of the biggest components of the Cretan diet is olive oil. It is complemented with a high intake of fruits and vegetables as well as a moderate intake of fish and wine. They of course don’t miss out on high amounts of physical activity every day.
The Mediterranean diet in general is rich in plant-based foods, fish, and olive oil. One may say that the reduced risk of most aging-related diseases in Crete including metabolic syndromes and neurodegenerative disorders are due to their diet.