Preparation of potent antioxidant nanosuspensions from olive leaves by Rapid expansion of supercritical solution into aqueous solutions (RESSAS)

Abstract

The aim of this work is to prepare and stabilize potent antioxidant nanoparticles such as α-tocopherol and β-amyrin from Olea europaea leaves using the RESSAS process. These compounds have a low bioavailability and efficacy, as they are barely soluble in aqueous media. For this reason, providing stable nanosuspensions out of them could solve the problem using an increased solubility. The effects of pressure, oven temperature, modifier volume and CO2 flow rate on the antioxidant activity index (AAI) of the RESSAS process outcome were analyzed by applying central composite design (CCD). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was conducted in aqueous solution to the determined AAI. In addition, the specifications of nanosuspension were studied using a dynamic light scattering (DLS) technique. The results emphasize the post-treatment of the particles, after particle formation and show that the RESSAS process leads to the minimization of particle agglomeration and improvement of AAI for the extracted nanosuspension.