Bioactive molecules isolated from olive pomace extract protect cells from calcium mediated damages

In this study we show that molecules extracted from olive pomace prevent cell death induced by Ca2+­overloading.Exposure of human neuroblastoma SKNBE, mouse brain endothelioma bEnd5 and human peripheral blood mononuclearcells to these molecules counteracts the Ca2+­induced cell damages by reducing the activation of the Ca2+­dependentprotease calpain. Indeed, this proteolytic enzyme is involved in key cellular processes including apoptosis. In order tocharacterize this cell protective effect, we purified the olive pomace extract and concentrated the phenolic fraction, whichcontained mainly tyrosol, caffeic acid, oleuropein and apigenin. However, none of these polyphenolic compounds,separately tested as purified molecules, showed the protective effect on cell viability following Ca2+­overloading. Hence,to identify the relevant bioactive molecules in the purified olive pomace extract, we performed a further fractionation byRP­HPLC. Only one of the fractions obtained, maintained the ability to protect the cells from damages induced by Ca2+­overloading. This finding indicates that the cell protective effect depends of molecules different from the mainpolyphenols present in the purified olive pomace extract. We hypothesize that the molecular characterization of thesemolecules would eventually define new strategies for therapeutic applications in pathologies characterized by alterationsof the intracellular Ca2+ ­homeostasis. These promising starting points prompted us to plan further investigations aimedto identify the chemical nature of the bioactive molecules contained in this extract and the specific cell target sites.