Protective effect of Hypericum perforatum Linn (St. John's wort) against hydrogen peroxide-induced apoptosis on human neuroblastoma cells

The medicinal plant Hypericum perforatum Linn, commonly known as St. John's wort, has been used as an antidepressant. To investigate whether St. John's wort possesses a protective effect against hydrogen peroxide (H₂O₂)-induced cytotoxicity in neuronal cells, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 4,6-diamidino-2-phenylindole staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, flow cytometry analysis, DNA fragmentation assay, and caspase-3 enzyme assay were performed on SK-N-MC human neuroblastoma cells. Cells treated with H₂O₂ exhibited several apoptotic features, while those pre-treated with St. John's wort prior to H₂O₂ exposure showed a decreased occurrence of apoptotic features. In addition, pre-treatment with St. John's wort inhibited H₂O₂-induced increase in caspase-3 enzyme activity. These results suggest that St. John's wort may exert a protective effect against H₂O₂-induced apoptosis in human neuroblastoma cells.