Modulatory effect of oleuropein on digestive enzymes

Oleuropein, a non-toxic secoiridoid, is the major component of olive polyphenols. Its content in olives and their oil depends, among other things, on the type of olives, the manufacturing process, and storage conditions. Oleuropein, as well as other phenolic compounds such as hydroxytyrosol and tyrosol, have been extensively studied for their beneficial effects in a variety of ailments such as cancer, blood pressure and heart problems, and an array of viral and bacterial diseases. We report an in vitro study to evaluate possible effects of the polyphenol oleuropein on enzymes involved in metabolism of proteins, carbohydrates and lipids. The enzymatic activity of some commercially available digestive enzymes (trypsin, pepsin, lipase, glycerol dehydrogenase, glycerol-3-phosphate dehydrogenase, and glycerokinase) was studied both in the absence and in the presence of oleuropein. Although further investigations are required to confirm these data in vivo, this in vitro study led us to hypothesize a new role for oleuropein as a metabolism modulator.