Anti-Inflammatory Activity and Mechanism of Sweet Corn Extract on Il-1 beta-Induced Inflammation in a Human Retinal Pigment Epithelial Cell Line (ARPE-19)

Age-related macular degeneration (AMD) is an eye disease associated with aging. Development of AMD is related to degeneration and dysfunction of the retinal pigment epithelium (RPE) caused by low-grade chronic inflammation in aged RPE cells leading to visual loss and blindness. Sweet corn is a good source of lutein and zeaxanthin, which were reported to exert various biological activities, including anti-inflammatory activity. The present study aims to investigate the anti-inflammatory activity and mechanisms of SCE to inhibit the production of inflammatory biomarkers related to AMD development. Cells were pretreated with SCE for 1 h followed by stimulation with IL-1 beta for another 24 h. The results demonstrated that SCE attenuated IL-1 beta-induced production of IL-6, IL-8, and MCP-1 and the expression of ICAM-1 and iNOS in a dose-dependent manner. In addition, SCE suppressed the phosphorylation of ERK1/2, SAPK/JNK, p38, and NF-kappa B (p65) in IL-1 beta-stimulated ARPE-19 cells. These results proved that SCE protected ARPE-19 cells from IL-1 beta-induced inflammation by inhibiting inflammatory markers partly via suppressing the activation of MAPK and NF-kappa B signaling pathways. Overall, SCE is a potential agent for the prevention of AMD development, which should be further evaluated in animals.