Protective Effects of Phillyrin on H2O2-induced Oxidative Stress and Apoptosis in PC12 Cells

Oxidative stress is a major component of harmful cascades activated in neurodegenerative disorders. We sought to elucidate possible effects of phillyrin, an active constituent isolated from the Chinese medicinal herb Forsythia suspense , on hydrogen peroxide (H 2 O 2 )-induced cell death and determine the underlying molecular mechanisms in neuron-like PC12 cells. By MTT assay and lactate dehydrogenase (LDH) leakage assay, we found that phillyrin treatment effectively protected PC12 cells against H 2 O 2 -induced cell damage. H 2 O 2 exposure induced oxidative stress in PC12 cells, as revealed by enhanced oxidative stress and decreased activities of antioxidative enzymes, which were inhibited by phillyrin pretreatment. ROS activated mitochondria-dependent apoptosis. The anti-apoptotic effects of phillyrin were also confirmed by acridine orange/ethidium bromide (AO/EB) staining. Mitochondrial membrane potential decrease, cytochrome c release, caspases activation, activation of AIF and Endo G were observed in H 2 O 2 -treated cells by rhodamine 123 or western blot. Interestingly, phillyrin effectively suppressed these changes. Moreover, phillyrin could inhibit H 2 O 2 -induced up-regulation of Bax/Bcl-2 ratio. In conclusion, phillyrin effectively inhibited H 2 O 2 -induced oxidative stress and apoptosis in PC12 cells.