Eucommia ulmoides Oliv. Bark. protects against hydrogen peroxide-induced neuronal cell death in SH-SY5Y cells

Ethnopharmacological relevance

Eucommia ulmoides Oliv. Bark. (EUE), has commonly been used to fortify the muscles and lungs, lower blood pressure, prevent miscarriage, improve the tone of liver and kidneys, and promote longevity the traditional tonic medicines of Korea, China, and Japan.

Aim of the study

In this study, we investigated that the neuroprotective activities and possible mechanisms of EUE aqueous extract in hydrogen peroxide (H₂O₂)-induced neuronal cell death in human SH-SY5Y neuroblastoma cells.

Material and method

We examined the effects of EUE against H₂O₂-induced cytotoxicity, DNA condensation, the production of reactive oxygen species (ROS), loss of mitochondria membrane potential (MMP), the proteolysis of cleaved poly-ADP-ribose polymerase (PARP), and the expression of Bcl-2, Bcl-xL, cleaved caspase-3, and release of cytochrome c. Moreover, we attempted to determine whether EUE suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK 1/2), and phosphoinositide 3-kinase (PI3K)/Akt.

Results

Pretreatment with EUE increased cell viability and inhibited cytotoxicity and DNA condensation. EUE also attenuated the increase in ROS production and MMP reduction. Western blot data revealed that EUE inhibited H₂O₂-induced up- or down-regulation of cleaved PARP, cleaved caspase-3, Bcl-2, and Bcl-xL. The EUE inhibited release of cytochrome c from mitochondria to the cytosol, and significantly attenuated H₂O₂-induced phosphorylation of JNK, p38 MAPK, ERK 1/2, and PI3K/Akt.

Conclusion

The potent neuroprotective capacity of EUE, shown in these experiments, may potentially be applied in the prevention or treatment of neurodegenerative diseases such as Alzheimer's disease (AD).