Olea europaea var. Oleaster a promising nutritional food with in vitro antioxidant, antiglycation, antidiabetic and antiproliferative effects

Advanced glycation end products (AGEs) generated from glycation might cause diseases such as diabetes and breast cancer. Antioxidants have an important role in protecting humans against infections and degenerative diseases due to their ability to neutralize AGEs. Olea europaea var. oleaster (Oeo) is an ancient plant widespread in the Mediterranean basin which is traditionally used as a source of antioxidants. The present research deals with phytochemical screening and the antioxidant properties of both aqueous and methanolic extracts of the Oeo fruit. Additionally, antidiabetic potential (α-amylase and α-glucosidase inhibitory activities) and inhibitory potential on AGEs formation have been investigated using the methanolic extract of the Oeo (ME-Oeo) fruit. The cytotoxic effect against two human breast cancer cell lines (MDA-MB-468 and MCF-7) was also investigated. Both aqueous and methanolic extracts showed a high phenolic and flavonoid content: by using HPLC-DAD-ESI/MS up to fifteen major compounds were positively identified. The methanolic extract showed better antioxidant activity than aqueous extract in all tests. Also, the ME-Oeo fruit showed high inhibitory effects on the production of Amadori products and AGEs from albumin in the presence of fructose and a high significant inhibitory effect against α-amylase (IC50 = 2.367 mg/mL) and α-glucosidase (IC50 = 1.272 mg/mL), respectively. The ME-Oeo fruit showed moderate cytotoxic activity against MDA-MB-468 cell line (IC50 = 35.16 µg/mL), and MCF-7 cell line (IC50 = 46.75 µg/mL). These results suggest the possibility of using ME-Oeo fruit as a source of natural bioactive compounds for the prevention of glycation-associated complications in diabetes and in cytotoxicity treatment.