Desenvolvimento de nanoemulsões como estratégia para proteção de compostos bioativos de Syzygium malaccense (Jambo vermelho) em séruns cosméticos

Abstract

Syzygium malaccense, popularly known as red jambo, is a plant of Asian origin found in Brazil in regions with a warm climate. Studies have shown that the leaves of this plant are a rich source of antioxidant compounds, which have the ability to neutralize free radicals and combat premature skin ageing. In view of this, the aim of this study was to incorporate the crude extract and purified fraction of S. malaccense leaves into a cosmetic serum formulation, developing nanoemulsions as a way of protecting the bioactive compounds. The extract was produced using an exhaustive solid-liquid extraction process, using a polar solvent. The extract was then purified by fractionation with different solvents. Subsequently, the samples were evaluated for their antioxidant activity using the DPPH and ABTS radical scavenging methods, iron reduction power (FRAP) and Folin-Ciocalteau reagent (RFC), and for their phenolic composition using high-performance liquid chromatography. The samples showed high antioxidant capacity, related to the presence of phenolic compounds. The samples were incorporated into the serums. The nanoemulsions were obtained using the high-energy ultrasonication method and then characterized in terms of mean diameter, polydispersity index, zeta potential and encapsulation efficiency. The formulations had particle sizes on a nanometric scale, with suitable polydispersity values and zeta potential values, indicating that the system has good physical and colloidal stability. The formulation was evaluated for encapsulation efficiency, showing promising values. The formulation was evaluated for preliminary stability under different storage conditions (45 ºC and -5 ºC) for 12 days, by means of organoleptic characterization (color, colorimetry, appearance and odour) and physicochemical characterization (pH, conductivity, density, spreadability, viscosity and antioxidant activity by the DPPH method). After the stability study, the formulation was stable, indicating that the development of nanoemulsions is a promising alternative for the protection of bioactive compounds in cosmetic formulations.