Hydroxytyrosol and Oleuropein Inhibit Mast Cell Degranulation Induced by Immune and Non-Immune Pathways

Abstract

The aim of the present work was to determine whether hydroxytyrosol and oleuropein, the major polyphenols in olives and olive oil, inhibit mast cell activation induced by immune and non-immune pathways. Purified peritoneal mast cells were preincubated in the presence of test compounds (hydroxytyrosol or oleuropein), before incubation with concanavalin A, compound 48/80 or calcium ionophore A23187. Dose-response and time-dependence studies were carried out. Comparative studies with sodium chromoglycate, a classical mast cell stabilizer, were also made. The supernatants and pellets after incubations were used for determination of β-hexosaminidase content by colorimetric reaction. The percentage of β-hexosaminidase release in each tube was calculated, which was taken as a measure of mast cell activation. Other samples of cell pellets were used for cell viability studies by the trypan blue dye exclusion test, or fixed for light and electron microscopy. Biochemical and morphological findings of the present study showed for the first time that hydroxytyrosol and oleuropein inhibit the degranulation of mast cells induced by immune and non-immune pathways. These results suggest that olive polyphenols, particularly hydroxytyrosol and oleuropein, may provide insights into the development of tools useful in preventing and treating mast cell-mediated disorders.