Soyasaponin Ab protects against oxidative stress in HepG2 cells via Nrf2/HO-1/NQO1 signaling pathways
Xiuying Liu, Keke Chen, Lijie Zhu, He Liu, Tao Ma, Qingying Xu, Tianyu Xie
Index: 10.1016/j.jff.2018.03.037
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Abstract
Soyasaponin Ab (SA) is a typical oleanane triterpene saponin isolated from soybean and represents effects of antioxidation and anti-inflammation. In this study, we found the expressions of some phase II detoxifying enzymes were stimulated by SA via the signaling pathway of nuclear factor erythroid 2-related factor 2 (Nrf2) in HepG2 cells. Luciferase assay results demonstrated that SA promoted the Nrf2 transcription via binding to the antioxidant response element. In addition, a combining of luciferase assay and Western blotting suggested that SA activated ERK1/2 signaling pathways, and made Nrf2 translocated from cytoplasm to nucleus. SA also upregulated some Nrf2-related antioxidant enzymes such as heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase-1 (NQO1), and glutamate cysteine ligase catalytic subunit (GCLC). Inhibition of si-Nrf2 resisted expressions of SA-induced antioxidant genes. Collectively, these results suggest that SA exerted its protection against oxidative stress via the Nrf2/HO-1/NQO1 signaling pathways.