Electrophilic thymol isobutyrate from Inula nervosa Wall. (Xiaoheiyao) ameliorates steatosis in HepG2 cells via Nrf2 activation

• Published in: Journal of functional foods 2022-01, Vol.88, p.104895, Article 104895
• Main Authors: Cheng, Xiang-Rong, Tu, Piao-Han, Dong, Wen-Le, Yu, Bu-Tao, Xia, Shu-Fang, Muskat, Mitchell N., Guan, Bin
• Format: Article
• Language: English
• Subjects: Electrophilic chemical components; Hepatic steatosis; Inula nervosa Wall; Nrf2; Thymol
• ISSN: 1756-4646; 2214-9414
• DOI: 10.1016/j.jff.2021.104895

[Display omitted] •Electrophilic components from Xiaoheiyao are knocked out using magnetic GSH probe.•Electrophilic components have the potential to ameliorate steatosis in HepG2 cells.•10-Isobutyryloxy-8,9-epoxythymol isobutyrate is discovered as a bioactive compound.•10-Isobutyryloxy-8,9-epoxythymol isobutyrate improves steatosis via Nrf2 activation. Xiaoheiyao, the rhizomes of Inula nervosa Wall., is a culinary spice known to contain some electrophilic Nrf2 activators that could potentially intervene in nonalcoholic fatty liver disease (NAFLD). In this study, the electrophilic components from Xiaoheiyao were annotated by comprehensive cheminformatics analyses on UHPLC-MS/MS data after being knocked out with glutathione (GSH)-immobilized magnetic microspheres. Their intervention effects against hepatic steatosis were investigated in free fatty acid (FFA)-treated HepG2 cells. The electrophilic components in Xiaoheiyao were found to be the major bioactive components preventing hepatic steatosis in FFA-treated HepG2 cells. In particular, 10-isobutyryloxy-8,9-epoxythymol isobutyrate (XHY-1) improved hepatic lipid metabolism disorder, Krebs cycle activity, oxidative phosphorylation, and the cellular and mitochondrial redox status. Moreover, XHY-1 activates the Nrf2-ARE signaling pathway through the up-regulation of Nrf2 expression and promotion of Nrf2 nuclear translocation. Molecular docking further showed that XHY-1 could conjugate with Cys151 in the BTB domain of Keap1 through the epoxy group. In conclusion, the electrophilic components of Xiaoheiyao, especially XHY-1, attenuated hepatic steatosis in FFA-treated HepG2 cells through activation of the Nrf2-ARE signaling pathway.