The Role of Oleuropein, Derived from Olives, in Human Skin Fibroblast Cells: Investigating the Underlying Molecular Mechanisms of Cytotoxicity and Antioxidant and Anti-Inflammatory Activities

Oleuropein is the main compound in olives, producing a relatively bitter taste for unprocessed and raw olives. It has been dramatically applied in herbal and traditional medicine and contains several biological functions, anti-inflammatory effects, antimicrobial characteristics, and anticancer and antioxidant activities. The present study dealt with the cytotoxic effect, reactive oxygen species (ROS) suppressor, and wound-healing activity of oleuropein on normal skin cells. Oleuropein’s cytotoxic and apoptotic effects were evaluated using MTT, flow cytometry, and DAPI staining. Moreover, oleuropein’s possible free radical scavenging properties were studied through several methods, including the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ABTS tests. The scratch assay was performed for wound-healing features, and qRT-PCR evaluated the expression of apoptosis-associated genes. Oleuropein was found to have a cytotoxic effect on skin cells at higher exposure doses. Apoptosis was induced in the flow cytometry histogram of the cells treated with oleuropein. The results also revealed the strong anti-inflammation and antioxidant effect of oleuropein. They suggested that more studies are necessary to assess the possible pharmacological use of oleuropein to prevent or decrease skin-related diseases.