Environmentally Sustainable Preparation of Oleuropein and Its Dialdehydic Derivatives in a Simple Pharmaceutical Formulation

In this paper, Krapcho's one-step decarbomethoxylation of oleuropein in DES is reported. Oleuropein used as reagent was extracted with water from olive leaves, widely available and inexpensive waste from the olive oil production chain. The reaction has been carried out in a series of ChCl-based DES of increasing acidity, with or without the addition of an amount of water, under microwave and conventional heating. The antioxidant power of the best reaction mixture, both in terms of biocompatibility of the medium and conversion of the starting material, was measured and compared with a natural phenolic mixture coming from EVOO. The reported results indicate that the formulation deriving by the Krapcho's one-step decarbomethoxylation of oleuropein in ChCl:Citric acid (1 : 1) DES can provide a ready-to-use "phenolic complex" with oxygen scavenging power similar to a mixture of phenols extracted from an EVOO that meets the requirements of EFSA health claim.