Multifunctional green synthetized gold nanoparticles/chitosan/ellagic acid self-assembly: Antioxidant, sun filter and tyrosinase-inhibitor properties

This paper accounts the first example about the development of a self-assembled supramolecular system based on the use of green-synthetized gold nanoparticles (AuNPs) and chitosan (CH), for solubilizing ellagic acid (EA) in water. AuNPs were synthetized by using Punica granatum Juice (PGJ) and, after their synthesis, in order to adsorb ellagic acid on the nanoparticles surface (AuNPs/CH/EA), the chitosan wrapping was performed (AuNPs/CH). For this purpose, chitosan having high viscosity, low and medium molecular weights were used and compared to check the best condition of work. The stability of the proposed system, before and after the addition of ellagic acid, under different conditions of work, i.e. solution pH, temperature and light irradiation were investigated demonstrating the stability of the proposed functional ingredient. The supramolecular system exhibited wide ranging properties such as antioxidant, skin lightening and sunscreen. More specifically, the % of antioxidant activity occurred around 80% and 60% from the DPPH and ABTS assays respectively; the tyrosinase inhibition was around of 50% and the Sun Protection Factor was found to be 20. Thanks to the multi-properties of the proposed functional ingredient it should exhibit several advantageous in cosmetic applications. The ingredient could be a valid alternative to the traditional nanostructured TiO2 and ZnO offering the possibility to have at the same time several properties due to the use of AuNPs (having light absorption and scattering ability, are biocompatible showing low toxicity) and EA. If these positive aspects are associated with the use of an eco-friendly and low-cost protocol for AuNPs synthesis, according to the Green Chemistry principles, a great interesting space is opened towards the study of PGJ-based AuNPs, as multifunctional platform in cosmetic.