Jaboticaba (Plinia peruviana) extract nanoemulsions: development, stability, and in vitro antioxidant activity

Objective: The aim of this work is to develop and characterize nanoemulsions containing jaboticaba extract (Plinia peruviana) aiming pharmaceutical and cosmetic applications. Methods: Nanoemulsions were prepared by high-pressure homogenization method using different concentrations of components (oil, surfactant, and extract) and homogenization pressures, in order to optimize the preparation conditions. Both unloaded and extract-loaded nanoemulsions were characterized according to their size, polydispersity, zeta potential, pH, morphology, and physical stability. Total phenolic and flavonoid contents in free jaboticaba extract and jaboticaba-loaded nanoemulsions were determined spectrophotometrically, while ellagic acid content was determined by high-performance liquid chromatography (HPLC) analysis. In vitro antioxidant activity was investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. Results: Colloidal dispersions exhibited a mean particle size around 200 nm, with monodisperse size distribution (PdI <0.3), and spherical shape. Stability studies showed that nanoemulsions were stable over 120 d of storage at room temperature. Jaboticaba nanoemulsions showed significant concentrations of phenolics, flavonoids, and ellagic acid, with encapsulation efficiency values higher than 90%. Antioxidant properties of jaboticaba nanoemulsions were demonstrated by its remarkable ability to scavenge DPPH free radicals and to reduce ferric-tripyridyltriazine complex, which can be attributed to their phenolic and flavonoid contents. Conclusions: The results suggest that nanoemulsions containing jaboticaba extract can be considered a promising candidate as a new antioxidant agent.