Attenuation of blue light-induced photo-oxidative stress through inhibition of NF-κB and MAPK signaling pathways, and activation of Nrf2 signaling pathway by djulis and its bioactive compounds

Abstract

The aim of this study is to investigate the djulis and its bioactive compounds to prevent blue light (BL)-induced photo-oxidative stress in ARPE-19 cells. After 6 h of BL exposure (peak at 452 nm), ARPE-19 cell viability significantly decreased, but treatment with water extract of djulis (WECF) at 0.1–25 µg/mL protected the cells from BL-induced phototoxicity. The cytoprotective effect of WECF were associated with a decrease in BL-induced oxidative stress and caspase-3 activity, and an increase in GSH levels and SOD activity. WECF also inhibited the expression of NF-κB protein and the MAPK signaling pathway, while upregulated heme oxygenase-1 (HO-1) via the Nrf2-mediated pathway. Moreover, betanin, kaempferol, quercetin and rutin, present in WECF, showed a protective effect against BL-induced photo-oxidative stress at 1–10 μM. Overall, WECF and its bioactive compounds have the potential to protect ARPE-19 cells from BL-induced retina damage, which could have therapeutic implications for retinal disease.

Keywords

• Djulis (Chenopodium formosanum)
• Bioactive compounds
• Blue light irradiation
• Retinal pigment epithelium (RPE) cells
• MAPK
• Nrf2