Liposomal formulations of Oleae europaea L.: analyzing the antioxidant and antidiabetic activities along with toxicity profile in pancreatic beta TC6 cell line.

Olea europaea L. (Oleaceae), is rich in phenolic content and has powerful antioxidant and antidiabetic activity. However, there are no medicinal products prepared due to this feature. Therefore, this study aims to characterize an O. europaea extract with strong antioxidant and antidiabetic properties and to prepare nanoformulations containing this extract. To determine the activities of the extracts prepared from the leaves of the plant, DPPH• and ABTS•+ scavenging, Fe+3 reducing activity, α-amylase, and α-glucosidase inhibition assays were performed. The oleuropein content of the absolute ethanol extract with the highest activity was analysed by HPLC. The characterized extract was loaded into liposomes and chitosan coated liposomes, and the long-term sustainability of their activity was investigated. The encapsulation efficiency was 65.2% for the liposome and 66.8% for the chitosan-coated liposome formulation. The amounts of the extracts released from the formulations were evaluated to exhibit antioxidant and antidiabetic activity.