Sustained antioxidant activity of quercetin-loaded lipid-core nanocapsules

Lipid-core nanocapsules (LNC) are vesicular nanocarriers prepared by solvent displacement. LNC have been previously prepared using medium-chain triglyceride and sorbitan monostearate as liquid and solid lipophilic components dispersed in the core, surrounded by poly(epsilon-caprolactone) (PCL). Our objective was to investigate the antioxidant activity of LNC containing quercetin (QUE), a radical scavenger, prepared with octyl methoxycinnamate and sorbitan monostearate as lipophilic core components and PCL as the polymer wall. We selected Saccharomyces cerevisae cells as the proposed biological model. QUE-LNC presented z-average diameter of 212 nm, pH of 5.51 and zeta potential of -11 mV. Multiple light scattering analysis (TurbiscanLab) showed a photon path length of 172 microm. Furthermore, a validated turbidimetric study determined that the density of particles in suspension was 1.66 x 10(13). DSC analysis showed that the melting temperature of PCL shifted to lower values when in contact with octyl methoxycinnamate indicating a molecular interaction. After 1 h (7 h), the QUE-LNC formulation and QUE solution incubated with H2O2 showed cell survival of 84.4% (87.7%) and 65.6% (7.3%), respectively. After 35 h of incubation, cell survival was 31.7% and 0.9%, respectively. The QUE-LNC showed sustained antioxidant activity and potential as a nanostructured material to formulate final products.