Preparation of oleuropein liposomes based on the freeze-drying of a monophase solution method

Abstract

Introduction: Oleuropein is used as an antimicrobial agent in food spoilage. In fact, it is a phenolic compound found in olives and the leaves of the olive tree. Despite the widespread use of oleuropein as an antimicrobial in food, its use is associated with problems such as degradation due to environmental conditions (degradation) and adverse sensory properties such as bitterness.Objective: The main objective of this investigation was to encapsulate oleuropein in the nanoliposomal formulation to achieve a form of this effective substance that has better efficiency and less undesirable characteristics.Methods: Nanoliposome containing oleuropein was prepared based on the freeze-drying method of a monophase solution.Then, the liposomes were characterized in terms of size, zeta potential, polydispersity index, TEM and encapsulation efficiency and release in hydrophobic environment. Also MICs of free and nanoliposoms against bacillus cereus were investigated by the standard broth dilution method. Results: The size and zeta potential of the prepared liposomes were from 47.6 to 1246.5 nm, and -43.1 to -11.38 mV, respectively. Encapsulation efficiency was 46/34% in the best formulation. Also, TEM results showed that the liposomes were nano-sized and spherical in shape.Investigation of antimicrobial properties showed that nanoliposome containing oleuropein improves the antimicrobial effect of oleuropein on bacillus cereus. Based on the release results in the hydrophobic medium, oleuropein is slowly and continuously released from nanoliposomes.Conclusion: It is possible to prepare nanoliposomes containing oleuropein with suitable properties and increased antimicrobial effects by using the modified lyophilization of mono-phase solution method.