Protective effects of a flavonoid-rich extract of Hypericum perforatum L. against hydrogen peroxide-induced apoptosis in PC12 cells.

Hypericum perforatum L. has been used traditionally as an antidepressant for the treatment of mild to moderate depression. In a previous study, a flavonoid-rich extract of Hypericum perforatum L. (FEHP) was prepared and its antioxidant activity was determined by a series of models in vitro. In the present study, the protective effects of FEHP against hydrogen peroxide-induced apoptosis in rat pheochromocytoma line PC12 cells were investigated by MTT assay, lactate dehydrogenase (LDH) release assay, flow cytometry analysis and DNA fragmentation assay. Following a 4 h exposure of PC12 cells to H2O2, a significant decrease in the cell viability and increased levels of LDH release were observed. However, pretreatment of PC12 cells with FEHP prior to H2O2 exposure elevated the cell viability, decreased the levels of LDH release and decreased the occurrence of apoptotic cells. Also, the intensity of H2O2-induced DNA laddering was inhibited in a dose-dependent fashion by a DNA fragmentation assay. These results suggested that FEHP possessed protective effects against H2O2-induced apoptosis in PC12 cells and FEHP might be useful in the treatment of oxidative stress-related neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease.