Allicin attenuates H2O2-induced cytotoxicity in retinal pigmented epithelial cells by regulating the levels of reactive oxygen species

Retinal pigmented epithelial cell (RPE) oxidative stress is known to have a vital role in the etiology of age-related macular degeneration (AMD). The present study aimed to investigate whether allicin, a natural product with antioxidant activity, was able to protect RPEs (ARPE-19) from hydrogen peroxide (H2O2)-induced damage, and to determine the underlying mechanisms. The 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to determine cellular viability, and reactive oxygen species (ROS) were detected using a ROS Assay kit. The results demonstrated that allicin was able to protect ARPE-19 cells from H2O2-induced damage in a dose-dependent manner. In addition, allicin attenuated oxidative stress by reducing the levels of intracellular ROS and malondialdehyde (MDA), and enhancing the glutathione/glutathione disulfide (GSSG) ratio. With regards to the underlying mechanism, allicin was able to markedly modulate the expression levels of ROS-associated enzymes, including superoxide dismutase, NADPH oxidase 4 and NAD(P)H dehydrogenase quinone 1, and elevate the activity of nuclear factor erythroid 2-related factor 2 in the H2O2-stimulated ARPE-19 cells. These results suggested that allicin may exert protective effects against H2O2-induced cyto-toxicity in RPEs via ROS regulation.