Extraction and purification of oleuropein from olive leaves

In this study, effect of some solvents (ethanol, acetonitrile and water) for the extraction of phenolic compounds was investigated. Solvent volume, temperature and duration of the extraction process have a positive correlation with the amounts of phenolic compounds and antioxidant activity. The amounts of phenolic compounds, especially oleuropein in the leaf extract is higher than the fruit extract, and the concentration of oleuropein content in leaves and fruits extract was 4900 and 1800 mg/L, respectively. The oleuropein extracted from olive leaves was purified with liquid-liquid extraction to above 98%, and its concentration in leaves was 9.8 w/w/% in dried leaves.