In vitro protective effects of encapsulated quercetin in neuronal models of oxidative stress injury

Abstract

ABSTRACTThe aim of the present study was to evaluate the protective effects of free and encapsulated quercetin against oxidative stress injury in neuronal SH-SY5Y cells and isolated rat brain synaptosomes. Quercetin (QR) was encapsulated in nanoparticles consisting of sodium alginate and chitosan and the ratio between both biopolymers was 10:1 or 1:10, respectively. The nanoparticles formulated with higher amount of sodium alginate were negatively charged, whereas those with higher chitosan amount were positively charged. The protective effects of free and encapsulated quercetin were studied in two in vitro models: H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells and 6-hydroxydopamine (6-OHDA) induced neurotoxicity in isolated rat brain synaptosomes. Comparing to free quercetin, quercetin encapsulated in the nanoparticles formulated with higher chitosan concentration exerted more pronounced neuroprotective activity in a model of H2O2-induced (1 mmol/L H2O2, 15 min) oxidative stress in neuroblastoma SH-SY5Y cells. A similar trend was observed in a model of 6-OHDA induced neurotoxicity in rat brain synaptosomes. In conclusion, encapsulation of quercetin in nanoparticles based predominantly on chitosan improved its neuroprotective activity in vitro.