Effect of nanoencapsulation of blueberry (Vaccinium myrtillus): A green source of flavonoids with antioxidant and photoprotective properties

The effect of nanoencapsulation on the in vitro photoprotection and antioxidant properties of blueberry (Vaccinium myrtillus) extract, before and after their dispersion into an oil-in-water emulsion and its final stability under stress conditions. Besides its skin healing activity, chitosan was chosen as wall material due to its natural origin, and possibility of obtention from shrimp residues. Chitosan/tripolyphosphate (TPP) nanoparticles loaded with blueberry extract were produced and characterized. Three different semi-solid oil-in-water emulsions, using Ecocert certified materials, were developed containing, respectively, (i) 5% (wt/wt) of extract-free nanoparticles, (ii) 5% (wt/wt) of extract-loaded nanoparticles, (iii) 2% (wt/wt) of free extract. Sun protection factor (SPF), antioxidant activity and stability under stress conditions were evaluated. The concentration of rutin was determined by High Performance Liquid Chromatography (HPLC). The loading of blueberry extract into nanoparticles kept their physicochemical properties, as well as SPF and antioxidant activity, over the course of the stability study. Extract-loaded nanoparticles were dispersed in a semi-solid oil-in-water emulsion and were shown to protect the extract from oxidation, suggesting that formulation containing 5% (wt/wt) of extract-free nanoparticles could presented lower difference between initial and final SPF and antioxidant activity values after 90 days of analysis. The developed formulation is proposed as a greener potential formulation to be used as photoprotector, especially if associated with physical sun filters. The role of blueberry flavonoids and the synergistic effect of nanoparticles against skin aging are here discussed.