Pueraria lobata Extract Protects Hydrogen Peroxide-Induced Human Retinal Pigment Epithelial Cells Death and Membrane Permeability

BACKGROUND: Pueraria lobata is used in traditional Asian medicine to treat cardiovascular diseases, diarrhea, diabetes mellitus, and diabetic complications such as diabetic retinopathy. Oxidative stress in retinal pigment epithelial cells is implicated in the pathogenesis of retinopathy and age-related macular degeneration (AMD). Here, we evaluated whether the P. lobata extract can prevent cell death and decrease membrane permeability in oxidative stress-induced human retinal pigment epithelial cells. METHODS: The effects of P. lobata extract on hydrogen peroxide- (H(2)O(2)-) induced oxidative stress were investigated using 2′,7′–dichlorofluorescin diacetate, western blotting, and immunohistochemistry in human retinal pigment epithelial cells. The effects of puerarin, daidzein, and daidzin isolated from P. lobata extract were also studied by determining cell death, reactive oxygen species (ROS) generation, and p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) phosphorylation. RESULTS: Our results showed that the P. lobata extract inhibited ROS generation, suppressed the disruption of zonula occludens-1 (ZO-1), and reduced membrane permeability in H(2)O(2)-induced human retinal pigment epithelial cells. Additionally, the P. lobata extract prevented the inhibition of p38 MAPK and JNK phosphorylation. CONCLUSION: Our findings suggest that the P. lobata extract has the potential to prevent AMD development by inhibiting the mechanism underlying oxidative stress-mediated ocular disorders.