Protective effects of echinacoside, one of the phenylethanoid glycosides, on H(2)O(2)-induced cytotoxicity in PC12 cells.

We have investigated the protective effects of echinacoside (ECH), one of the phenylethanoid glycosides, on H(2)O(2)-induced cytotoxicity in the rat pheochromocytoma cell line (PC12 cells). Our data show that application of ECH to H(2)O(2)-injured PC12 cells (HIPCs) increased cell viability and decreased the apoptotic ratio. Flow cytometry (FCM) and laser scanning confocal microscopy (LSCM) analysis suggested that ECH exerted its inhibitory effects on the formation of reactive oxygen species (ROS) and the accumulation of intracellular free Ca(2+) ([Ca(2+)]i). In addition, ECH elevated the mitochondrial membrane potential (MMP) in HIPCs. Furthermore, Western blot analysis revealed that ECH prevented an H(2)O(2)-induced increase of the Bax/Bcl-2 ratio by down-regulating Bax protein expression and upregulating Bcl-2 protein expression. In summary, ECH showed significant neuroprotective effects on HIPCs through the mitochondrial apoptotic pathway, and could be a potential candidate for intervention in neurodegenerative diseases such as Alzheimer's and Parkinson's disease.