Extraction of oleuropein from olive leaves and applicability in foods

Oleuropein is a phenolic compound found in all parts of the olive tree (Olea europaea L.), although at higher levels in the leaves. The health benefits associated with the consumption of oleuropein include the prevention of cardiac diseases, improvement in lipid metabolism, and decrease in obesity-related disturbs, among others. In addition, several studies have shown that oleuropein presents antimicrobial, antioxidant, and inflammatory properties. The scientific interest in the methods for the extraction of oleuropein from olive leaves has markedly increased in recent years, aiming to extend its application in foods, cosmetics, and drugs. In this review, the extraction procedures available in the literature are described according to their advantages and disadvantages that directly affect the extraction yield. The applicability of oleuropein in food products is also discussed.