Kinetic study of the acidic hydrolysis of oleuropein, the major bioactive metabolite of olive oil

The hydrolytic stability of Oleuropein (OE), the major bioactive molecule of olive oil was investigated under acidic conditions. For this purpose a reversed-phase liquid chromatography (HPLC) method was developed and validated using a C-8 column and a diode array detection system. Statistical evaluation of the proposed HPLC method showed good linearity, precision and accuracy so that it can be used for analytical purposes. The relative standard deviation (RSD) of the method was less than 3.76% and the LOQ was established to be 0.5 mu g/mL. OE was hydrolyzed at three different HCl concentrations (1, 0.1, and 0.01 N) under different temperatures. The results obtained were treated as logarithms of concentration vs. time because it was realized that the hydrolysis followed first order kinetics. The observed degradation rate constants k obs were determined as well as the corresponding half-lifes t(1/2) . Arrhenius plots were also constructed from the hydrolysis data. The results indicate that OE is stable under acidic conditions.