Attenuation of hydrogen peroxide-induced oxidative stress in SH-SY5Y cells by three flavonoids from Acer okamotoanum

Abstract

The flavonoids quercitrin, isoquercitrin, and afzelin were isolated from the ethyl acetate fraction of Acer okamotoanum. The effectiveness of these flavonoids in protecting human cells was investigated using SH-SY5Y neuronal cells. Oxidative stress was induced by hydrogen peroxide (H2O2) and cells treated with flavonoids had an increased viability as compared with untreated cells. The flavonoid-treated cells showed significantly less reactive oxygen species production and lactase dehydrogenase release than the untreated cells. Especially, quercitrin and isoquercitrin showed the strongest protective effects against oxidative stress among several tested flavonoids as determined by the results for cell viability, reactive oxygen species (ROS) production, and lactate dehydrogenase release. Furthermore, we measured the expression of inflammation- and apoptosis-related proteins. These flavonoids attenuated inflammation by downregulating the expression of cyclooxygenase-2, inducible nitric oxide synthase, and apoptotic signaling via inhibiting caspase activation. The present results suggest that three flavonoids of A. okamotoanum protect against cellular oxidative stress possibly through regulating inflammation, apoptosis, and ROS-scavenging.